Abstract: We theoretically investigate the quench dynamics in quantum impurity systems coupled to a spinpolarized reservoir. In particular, we consider a single quantum dot system and a large-spin magnetic molecule coupled to external ferromagnetic lead. We examine the response to a quench in the spin-dependent coupling strength to ferromagnetic lead as well as in the position of the orbital level. The dynamics is analyzed by studying the timedependent expectation values of the magnetization and spin-quadrupole moment. We predict the time-dependence of a ferromagneticcontact-induced dipolar exchange field and its nonmonotonic build-up, as well as the development of local quadrupolar exchange field. The relevant time scales describing the dynamics are identified.

Abstract: Graphene is a promising material for a spin channel in spintronic devices because of the large electron mobility and the long spin diffusion length [1]. Half-metallic Heusler alloys are the best materials for spin injectors and detectors due to the 100% spin-polarization of electrons at the Fermi level [2]. Combination of these materials can lead to the improvement of performance of the spintronic devices [3]. However, the growth of the Heusler alloys on the graphene was not studied before. Herein, we present the influence of the growth temperature on structural and magnetic properties of Co2FeSi Heusler alloys thin films deposited on: CVD graphene transferred on Si/SiO2, epitaxial graphene on SiC and HOPG (highly oriented pyrolytic graphite – whose surface is similar to graphene). The films were grown by molecular beam epitaxy (on graphene) and by magnetron sputtering (on HOPG). In particular, the films deposited on transferred and epitaxial graphene are polycrystalline, while Co2FeSi films deposited on HOPG grow with the (001) texture. Structural and magnetic properties, and in particular the differences in the growth between the graphene and HOPG substrates will be discussed.
 
This work is supported by the National Science Centre – Poland under the contract 2016/23/D/ST3/02121.
 
[1] W. Han et al., Nat. Nanotechnol. 2014, 9, 794.
[2] T. Kimura et al., NPG Asia Mater. 2012, 4, e9.
[3] T. Yamaguchi et al., Appl. Phys. Express 2016, 9, 063006.

Abstract: We demonstrate a design of all-ferrodielectric metasurface which exhibit sufficient enhancement of the Faraday rotation induced by particular grating mode excitation [1,2]. The metasurface is presented as periodic arrangement of cylinders (open dielectric resonators) which located on the substrate and both made of ferrodielectric. The conditions of the grating mode excitation are revealed for different geometrical parameters of the resonators forming the array. It was established that the Faraday rotation [3,4] is increased in several times versus uniform ferrodielectric layer with the same thickness at the corresponding resonant frequency. The effect is confirmed in the microwave measurements.
 
[1] V. I. Belotelov, I. A. Akimov, M. Pohl, V. A. Kotov, S. Kasture, A. S. Vengurlekar, A. V. Gopal, D. R. Yakovlev, A. K. Zvezdin, and M. Bayer, “Enhanced magneto-optical effects in magnetoplasmonic crystals,” Nature Nanotechnology 6, 370-376 (2011).
[2] A. V. Chetvertukhin, A. A. Grunin, A. V. Baryshev, T. V. Dolgova, H. Uchida, M. Inoue, and A. A. Fedyanin, “Magneto-optical Kerr effect enhancement at the Wood’s anomaly in magnetoplasmonic crystals,” J. Magn. Magn. Mater. 324, 21, 3516–3518 (2012).
[3] M. Inoue, M. Levy, and A. V. Baryshev, (Eds.). Magnetophotonics: From Theory to Applications (Springer Science Business Media, 2013).
[4] A. A. Girich, S. Y. Polevoy, S. I. Tarapov, A. M. Merzlikin, A. B. Granovsky, and D. P. Belozorov, “Experimental Study of the Faraday Effect in 1D-Photonic Crystal in Millimeter Waveband,” Solid State Phenomena 190, 365-368 (2012).

Abstract: Demonstration, in micromagnetic simulation, the self-imaging phenomenon (called the Talbot effect) for spin waves propagation in thin ferromagnetic film magnetized out-of-plane. We show that the diffraction grating created by the holes in thin permalloy film allows obtaining Talbot’s carpets formed by the transmitted spin waves at high frequencies, where the exchange interactions dominate, and at low frequencies where the magnetostatic interactions influence the shape of the dispersion relation. The analyzed effect is particularly interesting due to the potential application in magnonic devices, e.g. logic circuits.

Abstract: Phase and amplitude are the fundamental characteristics of spin waves that can be used to carry information. We propose here a method of the modulation of the phase of reflected spin waves from the edge of a thin ferromagnetic film. Utilizing micromagnetic simulations, we demonstrate that the application of narrow resonators on top of the edges can be used to mold the phase of the reflected waves. We show that near the Fano resonances, even small change of the resonator’s geometry significantly influences the phase of the reflected waves. Noteworthy, this resonator can be treated as a magnonic counterpart of metasurface since it enables spin waves modulation, i.e., manipulation of the phase at subwavelength distances.

Abstract: We investigate Broadband excitations of spin-wave packets by ultrashort laser pulses at different magnonic antidot crystals and continuous magnetic film interfaces exhibit surface spin-wave modes that propagate out of the crystal into the continuous film. The propagation distance depends on the direction of the applied magnetic field as well as the surface geometry of the crystal. Additionally, Spatially resolved measurements of the magnetization dynamics on thin CoFeB films reveal that the frequencies of resulting spin-wave modes depend strongly on the distance to the pump center. This can be attributed to a laser generated temperature profile. We determine a shift of 0.5 GHz in the spin-wave frequency due to the spatial thermal profile induced by the femtosecond pump pulse that persists for up to one nanosecond.

Abstract: State of the art x-ray microscopy allows an unprecedented insight into dynamic magnetic systems, featuring a spatial resolution of 20 nm and a temporal resolution of 20 ps. This technique uniquely allows us real space observation of artificial spin systems that have been created using contemporary nanolithography methods. To this end we have developed sophisticated measurement and evaluation techniques that allow the fast acquisition of full spin wave dispersion relations and the quantitative measurement of minute spin angles. We showcase this technique with three examples: magnetic droplets, magnetic skyrmions, and short wavelength spin waves.

Abstract: Quasicrystals are structures that exhibit long-range order, lack translational periodicity, but possess another noteworthy symmetry property, which is self-similarity by scaling [1]. Therefore, magnonic quasicrystals surpass regular magnonic crystals regarding provided by them possibilities of spin waves control: they offer complex, self-similar spin wave spectra, localization of spin waves inside the structure, and on the surfaces of the structure [2]. The results of joint collaborative research with the experimental groups will be shown, demonstrating the possibility of spin wave propagation through magnonic quasicrystal, the opening of additional mini-bandgaps [3], and the reprogrammability of the resonance frequencies, dependent on the magnetization order in magnonic quasicrystals [4]. The measurements of SWs propagating in a 1D Fibonacci sequence of dipolarly coupled permalloy nanowires are done with the help of a combined X-ray microscopic and Brillouin Light Scattering. The experimental results are interpreted using numerical calculations. Additionally, a simple model estimating frequencies of magnonic gaps in the spin wave spectra of the Fibonacci quasiperiodic structure matches the frequency mini-band gaps calculated numerically and measured experimentally. The demonstrated features of one-dimensional magnonic quasicrystals allow utilizing this class of metamaterials for magnonics and make them an ideal basis for future applications. We would like to acknowledge the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie GA Grant No. 644348 (MagIC) and NCN Poland Grant No. UMO2017/24/T/ST3/00173, No. UMO-2012/07/E/ST3/00538, and No. UMO-2016/21/B/ST3/00452, Helmholtz Zentrum Berlin/BESSY II is gratefully acknowledged for allocating beam time at the MAXYMUS end station. J.R. would like to additionally acknowledge the financial support from the Adam Mickiewicz University Foundation.
 

[1] C. Janot, Quasicrystals: A Primer 2nd edition, Oxford University Press, 2012
[2] J. Rychły, J. W. Kłos, M. Mruczkiewicz, M. Krawczyk, Spin waves in one-dimensional bicomponent magnonic quasicrystals, Physical Review B 92, 054414 (2015)
[3] Filip Lisiecki, Justyna Rychły, Piotr Kuświk, Hubert Głowiński, Jarosław W. Kłos, Felix Groß, Nick Trager, Iuliia Bykova, Markus Weigand, Mateusz Zelent, Eberhard J. Goering, Gislea Schutz, Maciej Krawczyk, Feliks Stobiecki, Janusz Dubowik, and Joachim Gräfe, Magnons in a Quasicrystal: Propagation, Extinction, and Localization of Spin Waves in Fibonacci Structures, Phys. Rev. Applied 11, 054061 (2019)
[4] F. Lisiecki, J. Rychły, P. Kuswik, H. Glowiński, J. W. Kłos, F. Groß, I. Bykova, M. Weigand, M. Zelent, G. Schutz, G. Gubbiotti, M. Krawczyk, F. Stobiecki, J. Dubowik, and J. Grafe, Reprogrammability and scalability of Fibonacci magnonic quasicrystal, Physical Review Applied 11, 054003 (2019)

Abstract: Magnetoreactance is a magnetic-field dependence of the imaginary part of the electrical impedance. While giant magnetoimpedance (GMI) of ferromagnetic microwires or sandwiched multilayers is being widely applied for sensing magnetic field with a superior field sensitivity, it is suppressed at the nanoscale in the accessible (microwave) range of the current frequency, which limits the spatial resolution of the sensors. A giant magnetoreactance (GMX), that is assisted by driven oscillations of the ferromagnetic domain walls, is an alternative to GMI when miniaturizing the field sensor. Efficiency of GMX is studied for several nanomagnetic systems by means of micromagnetic simulations.
 
[1] A. Janutka, K. Brzuszek, JMMM 465 (2018) 437.
[2] A. Janutka, K. Brzuszek, J. Phys. D 52 (2019) 035003.
[3] A. Janutka, K. Brzuszek, IEEE Magn. Lett. 10 (2019) 6103105.

Abstract: Nanoindentation is a well-established characterization technique for the extraction of mechanical information of nanomaterials. Nevertheless, much of the potential of the technique is still overlooked by the functional oxides and the electronics community, due to traditional preconceptions about their applicability and use. In this talk, some of the unique capabilities of the technique will be discussed. Followed by specific applications on different materials such as flexoelectric, ferroelectric and ferromagnetic. Finally, the potential of nanoindentation as a powerful tool for information technology, energy, and communications, will be presented.

Abstract: Magnetic properties of a single Co layer depend on its thickness and a type of buffer and capping film [1]. In multilayered systems magnetic configurations are more complex due to interlayer coupling depending on the nonmagnetic spacer thickness [2]. Irradiation of such structures with an ion beam substantially affects anisotropy, the coupling strength or type and even suppresses their ferromagnetic nature [3,4]. Application of a focus ion beam enables local magnetic modifications in the nanometre scale leading to 3D magnonic crystals (MC) creation. Several types of MCs are proposed for various stacks of the sample and applied fluence of the ion beam.
 
Acknowledgements: This work was supported by the National Science Centre in Poland under the projects: 2014/13/B/ST5/01834 and the EU European Regional Development Fund (REINTEGRATION 2017 OPIE 14-20).
 
[1] A. Wawro et al., J. Phys. D 50, 215004 (2017)
[2] Z. Kurant et al., J. Magn. Magn. Mat. 475, 683 (2019)
[3] A. Maziewski et al., Phys. Rev. B 85, 054427(2012)
[4] A. Wawro et al., Phys. Rev. Appl. 9, 014029 (2018)

Abstract: Inversion-Asymmetric heterostructures have been fabricated by molecular beam epitaxy (MBE) technique, in which Co magnetic layer is surrounded by Pt and W material. The W/Co/Pt and Pt/Co/W systems exhibit the high spin-orbit coupling (SOC) and iDMI (interfacial Dzyaloshinskii Moriya interaction). The labyrinth-like magnetic domains observed in as-deposited the W/Co/Pt multilayers evolve into parallel stripe domain structure (forming 1D magnonic crystals) after saturation in the magnetic field applied in the sample plane, followed by an inplane ac demagnetization with decreasing amplitude. The average width of the labyrinth and parallel strip domains decrease with the repetition number of multilayers. Additionally, FMR and VNA-FMR spectra reveal resonance lines originating from uniform ferromagnetic precession (above saturation field) and from stripe labyrinth domain structure below the saturation field. Obtained results give insight into the dynamics properties of the samples which can be considered as MCs.
 
Acknowledgements: This work was supported by the EU European Regional Development Fund (REINTEGRATION 2017 OPIE 14-20).

Abstract: Ir/Co/Pt and Pt/Co/Ir trilayers with a wedged Co layer (Co thickness d=0±3.6nm) were deposited by magnetron sputtering on naturally oxidized Si substrates with a Ta/Au buffer. Their magnetic properties have been investigated using magneto-optical polar Kerr effect and Brillouin light scattering (BLS) technique in the Damon-Eshbach geometry. We have employed Brillouin Light Scattering spectroscopy in backscattering geometry for DMI constant D_S and spectral linewidths studies. D_S was nearly two times larger for the Ir/Co/Pt trilayer than for the Pt/Co/Ir with opposite chirality. The effective uniaxial magnetic anisotropy and D_S depend non-monotonically on d with a maximum at d ≈ 1.2 nm. The asymmetry in linewidth for Stokes and anti-Stokes peaks is observed for both Ir/Co/Pt and Pt/Co/Ir trilayers for d < 1.6 nm, and it is increasing with decrease of Co thickness. Acknowledgements: Supported by Polish National Science Center projects: DEC-2016/23/G/ST3/04196 Beethoven and UMO-2018/28/C/ST5/00308 SONATINA.

Abstract: [Co(d_Co)/Pt(d_Pt)/Ir(d_Ir)]_N and [Co(d_Co)/Ir(d_Ir)/Pt(d_Pt)]_N multilayers were deposited by magnetron sputtering. Different dCo was chosen to approach spin reorientation transition SRT from perpendicular to in-plane magnetization state. Different coupling between layers was obtained changing spacer layers thicknesses dIr and dPt. Investigation of magnetic characterization was done using longitudinal and polar magneto-optical Kerr effect MOKE, vibrating sample magnetometer VSM, Brillouin light scattering BLS spectroscopy, magnetic force microscopy MFM, VNA-FMR and FMR spectroscopy. The following magnetization distribution was deduced from magnetization curves and magnetic domain imaging: large macrodomain (micrometer size) differentiated by inplane “core” magnetization modulated by small nano-domain differentiated by out-of-plane magnetization. Hysteresis of BLS signal (measured also without magnetic field) was found. The in-plane “core” magnetization in domains seems to be responsible for BLS signal. Work supported by Polish National Science Center projects: DEC-2016/23/G/ST3/04196 Beethoven and UMO- 2018/28/C/ST5/00308 SONATINA.

Abstract: Exploiting the results of micromagnetic simulations, I will demonstrate the effect of Dzyaloshinskii-Moriya interaction (DMI) on static and dynamic magnetic properties of ultrathin single films and multilayer systems. Beside a DMI magnitude, other parameters were also adjusted, like the perpendicular magnetic anisotropy (characterized by the quality factor Q) and external magnetic field. Playing with the parameters, several types of magnetic textures were observed: domains with narrow wall of either Bloch or Neel type, spin spirals, skyrmions, conical spin spirals, or in-plane magnetization configuration. Multilayer systems were also modeled with different types of nonmagnetic spacers, and different coupling between magnetic films, what led to even more interesting variety of possible magnetization states. The structures were also characterized by their magnetic susceptibility and resonant oscillations of magnetization. Acknowledgements: Work supported by Polish National Science Center project DEC-2016/23/G/ST3/04196 Beethoven.

Abstract: This contribution presents the results of ab initio calculations of selected magnetic parameters of the L1₀ FeNi phase, which are the magnetocrystalline anisotropy energies (MAEs), the full potential calculations of the anisotropy constant K₃, spin and orbital magnetic moments, and the magnetostrictive coefficient λ₀₀₁ [1]. Furthermore, the calculated 3D k-resolved map of the MAE combined with the Fermi surface analysis gives a complete picture of the MAE contributions in the Brillouin zone. To increase the certainty of the result, the MAEs were calculated by using three different ab initio codes. All three codes employ the full potential and generalized gradient approximation (GGA) and give the MAEs below 0.5 MJ m⁻³. It is expected that due to the limitations of the GGA this values are underestimated. The more reliable model including orbital polarization corrections doubles this value [2], whereas the experimental values of the anisotropy constant K₁ from the literature oscillate around 1.0 MJ m⁻³ [3]. The L1₀ FeNi has further potential to improve its MAE by modifications, like for example tetragonal strain or alloying.
 
[1] M. Werwiński and W. Marciniak 2017 J. Phys. D: Appl. Phys. 50 495008
[2] Y. Miura, S. Ozaki, Y. Kuwahara, M. Tsujikawa, K. Abe, M. Shirai, 2013 J. Phys.: Condens. Matter 25 106005
[3] L.H. Lewis, F.E. Pinkerton, N. Bordeaux, A. Mubarok, E. Poirier, J.I. Goldstein, R. Skomski, K. Barmak 2014 IEEE MAGNETICS LETTERS 5 5500104.

Abstract: One of the main limitation of the storage density of a contemporary MRAM cell is the size of the transistor capable of driving sufficiently high current density needed to switch magnetic tunnel junction (MTJ). This limitation can be overcome by using so-called multi-bit MRAM cell. We present a method of manufacturing such multi-bit cells [1] with use of serially connected standard MTJs. The device may also be used as a memristor in neuromorphic computing [2-3]. Such design is very simple to manufacture, but due to spread of parameters of MTJ some limitations are observed. Mainly an ability to distinguish adjacent resistance states is reduced as well as define voltages for writing reduces as more non-equal elements are connected. To address this issue a way to determine maximum capacity of such multi-bit cell is needed. Therefore we also propose a behavioural simulation of such multi-bit cells. We also present complete analysis of limitations of the design. Scientific work funded from budgetary funds for science in 2017-2018, as a research project under the “Diamond Grant” program (Polish Ministry of Science and Higher Education Diamond Grant No. 0048/DIA/2017/46).
 
This work is supported by the Polish National Center for Research and Development grant No. LIDER/467/L- 6/14/NCBR/2015. T.S. acknowledges the SPINORBITRONICS grant No. 2016/23/B/ST3/01430.
 
[1] Rzeszut, P. et al. J. Appl. Phys. 125 (2019): 223907
[2] Torrejon, J. et. al. Nature 547 (2017): 428-431 [3] Raymenants, E. et. al. J. Appl. Phys. 124 (2018): 152116

Abstract: Spin waves are a promising candidates as a carriers for the next-generation low-energy signal processing devices. Here, we present the operation and we analyze the performance of the device which amplifies and modulates the spin wave by the ac electric field through the spin-transfer torque. Although the spin-transfer torque is regarded as a non-selective effect, i.e., it affects all the spin-wave modes together with noise, in our work we investigate the mechanism of this torque which is related to the specific spin wave symmetry and group velocity. As a consequence, it affects only coherent spin-wave modes but not noise. The system consists of two high-κ dielectric thin-film capacitors separated by ferromagnetic bilayer. The magnetization dynamics is affected non-resonantly with an ac voltage applied to such heterostructure by the spin accumulation. The spin accumulation is generated by the charge-mediated magnetoelectric effect (i.e., spin-dependent surface screening) and interacts with magnetization through the so-called field-like and anti-damping spin transfer torques. The spin transfer torques lead to the periodic spin wave amplification and attenuation with the frequency of the applied ac voltage. We show the criteria for the effective amplification and dependences of the obtained gain on the applied voltage amplitude and spin wave frequency. The generation of non-equilibrium spin density through dynamic spin-dependent surface screening in the proposed magnetoelectric heterostructure allows to reduce the thickness of fixed magnetization layer used in conventional spin valve to a few nanometers, thus the proposed effect can significantly contribute to miniaturization of the spintronic devices. The study has received financial support from the National Science Centre of Poland under grant 2018/28/C/ST3/00052. [1] P. Graczyk, M. Krawczyk, Spin-polarized currents driven by spin-dependent surface screening, arXiv:1902.06481

Abstract: Both anisotropy and damping is a function of spin-orbit coupling (SOC). It is commonly observed that the damping increases with increasing perpendicular magnetic anisotropy (PMA). It is believed that this is due to their relation to SOC. We have studied Au/Co/Au samples after ion bombardment, which is a known method to modify PMA. We have found that although PMA changes significantly nonmonotonically with ion fluence, the damping changes monotonically. In summary, we believe that the connection between damping and PMA is not a simple relation to SOC. This work was supported by DAAD within the program PPP Polen 2018 under Grant No. 57392264

Abstract: The development of new methods to modify magnetic properties is important in many areas. In particular, this applies to magnonics, where artificial modulation of magnetic parameters can be used to control and manipulate spin waves. Here, we present two methods for achieving such modulation. The first uses ion bombardment of ferrimagnetic layered systems; and the second, plasma oxidation of ferromagnetic layers. Both methods allow to obtain layers with periodically varied properties without topographical changes. This opens new ways to generate magnonic crystals.
 
This work was supported by the National Science Centre in Poland Sonata-Bis (DEC- 2015/18/E/ST3/00557) project. B. A. acknowledges support from project No. POWR.03.02.00-00-I032/16 under the European Social Fund – Operational Programme Knowledge Education Development, Axis III Higher Education for Economy and Development, Action 3.2 PhD Programme.

Abstract: The recent research has pointed to nanostructuring as a highly efficient approach to reducing thermal conductivity. One example of nanostructured materials are porous/holey phononic crystals (PnCs), which thermal conductivity can be engineered by means of the surface-to-volume ratio and surface roughness. Tuneable thermal properties make these structures good candidates for integrated heat management devices, for instance for waste heat recovery or heat rectification. In particular, the thermal rectification means that the magnitude of heat flux changes when the temperature gradient is reversed in direction. As a step towards heat rectification using silicon porous membranes in this work, we studied both thermal conductivity and its temperature dependence on a geometric parameter, i.e. the surface-to-volume ratio.

Abstract: The investigations about the phenomena involving interactions between thermal magnons and phonons have grate interest in modern emerging field of spintronics. In our studies, we determine the dispersion relation of thermal magnons and phonons in the CoFeB/Au multilayer deposited on a silicon substrate with Ti and Au buffer layers using Brillouin light scattering spectroscopy. We choose two geometries oblique geometry, (where the angle between magnetic field and wave vector is 45°) and Backward volume geometry (where the magnetic field and wave vector are perpendicular to each other). We found three different types of spin waves (Backward volume mode (BV-SW), perpendicular standing mode (PS-SW) and Damon-Eshbach mode (DE-MSW) and two phonon modes (Rayleigh (R-SAW) and Sezawa (S-SAW).

Abstract: We have investigated surface acoustic waves’ and spin waves’ dispersion relations in [Ni80Fe20/Au/Co/Au]10 multilayers. The method we used in our investigations was high resolution Brillouin spectroscopy. The thickness of 0.8 nm has been chosen for cobalt (Co) layer as it exhibits in-plane effective anisotropy. It allowed us to gather spectra of spin waves for two canonical geometries. In both cases spin wave’s wave vector lies in the plane of our sample, the difference occurs with the orientation of wave vector vs. static magnetization: in one geometry those vectors are perpendicular (Damon-Eschbach spin wave), while in the other they are parallel to each other (Backward Volume spin wave). The main goal of our experiment was to investigate the crossing regions of phononic ang magnonic dispersion relations.

Abstract: The unique Strain Modulated Ferromagnetic Resonance (SMFMR) technique will be presented, which allows determination of the magnetoelastic properties of thin magnetic films or ribbons, viz. magnetoelastic constants of the material. The SMFMR technique is successfully applied for investigation of thin layers of Co₂FexMn_1−xSi (CF_xM_1−xS), Co₂Fe_0.4Mn_0.6Si (CFMS) and Co₂FeGa_0.5Ge_0.5 (CFGG) Heusler alloys. The alloys mentioned above are characterized by high spin polarization and are good candidates for technical applications, among others in spintronics and magnonics; the magnetoelastic properties, magnetic anisotropy and dissipative properties play an important role in these materials. Several effects are investigated: the effect of the magnetic layer composition changing (CF_xM_1−xS), the finite thickness of the magnetic layer and the use of various buffer and surface layers (CFMS and CFGG). This work is partially supported by the National Science Centre of Poland – project number 2018/31/B/ST7/04006.

Abstract: An intriguing feature observed in modern refinements’ results of quasicrystals in the log-log plot of calculated vs. observed intensities is a characteristic bias in the low-peaks regime [e.g. 1,2]. The underestimation of the calculated diffraction intensities is of an unknown origin so far. The two possible reasons are most likely: (i) improper phasonic correction conventionally used in the form of the exponential Debye-Waller factor [3], and/or (ii) multiple scattering effect [4]. In our previous studies based on the model calculations we showed that the new correction for phasons developed within the statistical approach is potentially useful to solve the problem of a bias [3]. The correction for phasons (understood as flips/rearrangement of tiles in the quasiperiodic tiling) is made at the stage of the structure factor calculation, and it assumes the fragmentation of the probability distributions of atomic positions (called also the average unit cell, AUC, which is a real-space equivalent of the atomic surface/occupation domain in the hyperspace description, more on the AUC method in [5]). The Fourier transform of the “fragmented” (influenced by phason flips) AUC gives a diffraction pattern affected by a phasonic disorder. The only parameter to fit is a flip ratio (a probability of a single tile rearrangement in the structure). We assume only two types of flips (in regions of two thin and one thick, or two thick and one thin rhombuses, which build a hexagon), the phason-phonon coupling and the secondary phason flip effects are neglected. Recently we developed also a phenomenological way of diffraction data treatment in terms of the multiple scattering effect [6]. It is based on the Rossmanith theory [7 and later works] and considers a redistribution of intensities among all diffraction peaks with a given probability (the probability parameter is to be fitted). The two corrections are included in our refinement procedure developed within the statistical method. In the presentation we will show the application of new corrections to the diffraction data (with different refinement strategies) for decagonal AlCuRh quasicrystal, originally studied by Kuczera et al. [1]. The final results are: the value of R-factor is  6in the original refinement) with phasonic ADP of 1.35A2, phason flip probability of 1.34probability of 4.2×10-7. The results were published in [6].
 
[1] P. Kuczera, J. Wolny, W. Steurer, Acta Cryst. B 68, 578 (2012).
[2] H. Takakura, C.P Gomez, A. Yamamoto, M. de Boissieu, A.P. Tsai, Nature Mater. 6, 58 (2007).
[3] J. Wolny, I. Bugański, P. Kuczera, R. Strzałka, J. Appl. Cryst. 49, 2106 (2016).
[4] H. Takakura, R. Mizuno, Mater. Struct. 22, 281 (2015).
[5] R. Strzałka, I. Bugański, J. Wolny, Crystals 6, 104 (2016).
[6] I. Bugański, R. Strzałka, J. Wolny, Acta Cryst. A 75, 352 (2019).
[7] E. Rossmanith, J. Appl. Cryst. 32, 355 (1999).

Abstract: Phasons are the structural defects that are specific for quasicrystal. They are local rearrangements of the constituent elements in the quasiperiodic structure. We investigated the perturbed Fibonacci sequences of stripes with lower concentrations of phasonic defects. The goal of this study is to find the impact of the phasonic-like disorder on the spectrum and the localization of spin wave eigenmodes in magnonic quasicrystals.
 
The authors acknowledge the financial support of the National Science Centre Poland for Grant No. 2016/21/B/ST3/00452 and UMO-2017/24/T/ST3/00173.

Abstract: Droplet solitons are magnetization fluctuations that preserve their shape as they precess with uniform frequency. We introduce an effective energy ξ that quantifies the work done (against damping and spin torque) to create a fluctuation of arbitrary shape θ(ρ). We show that, for specific values of σ, some soliton solutions are saddles of ξ. This allows us to calculate thermal activation barriers ∆ξ between uniform precession at the ferromagnetic resonance and stable solitons. We present results of ∆ξ as a function of σ for a variety of nanocontact radii ρ^*.

Abstract: Magnetic skyrmions are topologically protected nano-meter sized chiral spin textures. Due to their various unique features, such as stability given by their topology, they are considered as potential candidates for information carriers in next generation data storage devices, like racetrack memory. Therefore, it is crucial to be able to manipulate their current-induced motion. We extend the idea to control motion of skyrmion in 2D plane with the in plane electric current pulses. This goal we have achieved through the use of magnetic antidot arrays. We have demonstrated experimentally that magnetic skyrmions can stabilize in a magnetic antidot array based on Ta/Co/Pt multilayers. Moreover with micromagnetic simulations we show that in such an antidot array the skyrmions can be guided in different directions. Depending on both, the size of the antidots and the current density, different types of skyrmion motion on the film plane were found, also the one shown in figure. Thus, magnetic antidot arrays can be used as a controller for skyrmion motion by using properly designed sequences of electrical current pulses, which makes them a promising candidate for current driven skyrmion motion control.

Abstract: We propose a model of spin-wave diode which is based on the effect of unidirectional coupling of spin waves in wide frequency range in bilayered ferromagnetic system. This effect bases on Dzyaloshinskii-Moriya interaction and dipolar coupling. Our spin-wave diode consists of ferromagnetic stripe lying above the ferromagnetic layer. Unidirectional coupling permits spin waves to transfer to the stripe when propagating in coupling direction, while in non-coupling direction the spin-wave transfer is very weak. Structure with additional layer coupled with the stripe can be proposed as a spin-wave circulator.

Abstract: We study spin wave dynamics in thin films with perpendicular magnetic anisotropy patterned with a square lattice of antidots. We show reach spin-wave spectra at remanence which indicates the non-collinear magnetization states around the antidots. The obtained results of spin-wave dynamics in these thin films with complex, but periodic magnetization textures, allow as to point out features promising for new phenomena in magnonics and their potential usefulness for applications.

Abstract: One of the main goals of performing FMR experiments is to find how the magnetic energy of a sample under investigation depends on magnetic field direction with respect to a sample crystallographic axes. This information is usually obtained by examining the experimental dependence of the resonance field value on its direction in space. The traditional analysis of experimental data is carried out using the well-known Kittel or Smit-Beljers equations describing the precessional motion of the sample magnetization. We propose [1] a new FMR data analysis method by referring to the geometric meaning of the Smit-Beljers equation: the resonance frequency of the magnetic moment precessional motion is equal to the Gaussian curvature of the spatial distribution of the magnetic free energy. This approach allows finding all the values of relevant physical quantities with high accuracy (the saturation magnetization M, g-factor, demagnetizing tensor N_αβ and magnetocrystalline anisotropy constants K_α) and consequently the spatial distribution of the free energy from a single set of FMR experimental data. We tested successfully [1] this approach using the cross-validation procedure [2] for bulk magnetite, (Ga,Mn)As thin film, YIG ultrathin film, Co ultrathin film and Fe thin film. Note, that it was necessary while doing the cross-validation, to use a proper form of the free energy dependence on all above mentioned magnetic parameters characterizing the sample of each ferromagnet under investigation. Therefore, the criterion of the correctness of the free energy formulas given in [2] was also applied in this work. Let us emphasize that none of the known methods of analysis of FMR experiments does give such universal opportunities.
Acknowledgments
Supported by NCN grant No. DEC-2013/08/M/ST3/00967.
References
[1] P. Tomczak and H. Puszkarski, arXiv:1901.01207.
[2] P. Tomczak and H. Puszkarski, Phys. Rev. B 98, 144415 (2018).

Abstract: In thin-film bicomponent magnonic crystals (MCs) an in-plane magnetization causes the demagnetizing field to occur around interfaces between constituent materials. The field has a great impact on the spin-wave spectrum, e.g. in cobalt-permalloy MCs at the low external magnetic field the lowest-frequency spin waves are excited in Co much more likely than in Py regardless the matrix or rods are made from Co. As a consequence the nonuniform softening of spin waves takes place. We show it could be very useful mechanism to design complete magnonic gaps with different sensitivity for the tiny change of the external field.
 
[1] S. Mamica, M. Krawczyk, and D. Grundler, Non-uniform spin wave softening in 2D magnonic crystals as a tool for opening omnidirectional magnonic band gaps, Phys. Rev. Applied 11, 054011 (2019). arXiv: 1810.04005
[2] S. Mamica and M. Krawczyk, Reversible tuning of omnidirectional band gaps in two-dimensional magnonic crystals by the low magnetic field, (2019), arXiv:1906.07469

Abstract: Any defect of periodicity is a potential localization of one or several bound modes. They differ from the bulk modes in that their wave functions decay exponentially with the distance from the defect in contrast with bulk mode showing a Bloch oscillatory behavior typical of propagative waves. In this note we study possibilities of existence of end bound (edge) modes in 1d systems of macrospins of selected shapes and test validity of some simplified models in the description of the lowest frequency range dynamics in such systems. The simplest possible model by Stoner and Wohlfarth assumes the whole magnetic moment of the macrospin concentrated in one point. The dipolar interactions are, thus, very strong. The configurations of finite magnetic chains obtained with this model are very interesting in that they show a number of tilted structures as a function of a magnetic field perpendicular to the chain. More developed model involves long 1D thin threads or wires. We have found a simple analytic expression for the dipolar interactions in such threads. The latter model reproduces fairly well the lowest excitations in the finite chains of macrospins with, however, selected geometries. We will discuss the validity of the models and the best physical realization of bound states in the finite chains.

Abstract: Algebraic Bethe Ansatz (ABA), known as the way of expressing a unique exact result of a quantum onedimensional N-body problem – the eigenproblem of the Heisenberg Hamiltonian for the chain of N spins 1/2 , can be also seen as a tool for various operations with systems of qubits, prepared in highly correlated multiparticle states with precisely prescribed properties. As a rule, one uses ABA in its off-diagonal version, in order to create single-magnon states with rapidities resulting from Bethe Ansatz equations – a system of r highly nonlinear algebraic equations which yields exact eigenstates of an integrable model. Here, we advocate for the diagonal version of ABA, namely for an immediate solution of (roughly) N spectral problems for constants of motion, generated from the transfer matrix – the trace of the monodromy matrix. The resulting system of constants of motion provides a realisation of a positive operator-valued measure (POVM), that is, a complete set of commuting operators along the prescripyion of Dirac. The program can be computationally realised only for a small number N of qubits, but it might be pretty practical for typical procedures carried by Alice and Bob.

Addresses:
(1) Institute of Physics, University of Zielona Góra, Poland
(2) Joint Laboratory of Optics of Palacky University and Institute of Physics of Czech Academy of Sciences, 771 46 Olomouc, Czech Republic

Abstract: Motivated by the proposal for quantification of Bell nonlocality [2], we present our results of the analysis of this concept, namely, the volume of violation. This new measure of nonlocality has been proposed to prove that the anomaly between maximally entangled states and states that maximally violate Bell inequality is caused by the method of quantifying nonlocality itself, and such anomaly disappears when the volume of violation is applied. We prove that this is not the case for all bipartite quantum systems with dimension d×d [1].
 
[1] Artur Barasiński, Mateusz Nowotarski Phys.Rev. A 98, 022132 (2018)
[2] E. A. Fonseca, Fernando Parisio Phys.Rev. A 92, 030101 (2015)

Addresses:
(1) Quantum Optics and Engineering Division, Institute of Physics, University of Zielona Góra, Zielona Góra, Poland
(2) Institute of Physics, Częstochowa University of Technology, Częstochowa, Poland

Abstract: Despite the relatively large electron-phonon coupling constant for vanadium, the quantities such as the order parameter, the specific heat, and the thermodynamic critical field determine the values of the dimensionless ratios not deviating much from the predictions of the BCS theory. This result is associated with the reduction of the strong-coupling and the retardation effects by the high value of the Coulomb pseudopotential. It has been shown that the results of the Eliashberg formalism can be relatively precisely reproduced with the help of the semi-analytical formulas, if the value of μ is determined on the basis of the T_c-Allen-Dynes expression. The attention should be paid to the fact that in the numerical and in the semi-analytical approach the comparable values of the thermodynamic parameters for the same μ have been obtained only in the vicinity of the point.

Abstract: The system ability to produce maximally or almost maximally entangled states is important for the development of quantum information theory and its applications. Such states are necessary for quantum communication, quantum cryptography or quantum calculations. As a source of maximally entangled states will be considered the system consisting of two coupled nonlinear oscillators excited by a series of ultra-short coherent pulses. For such a system the influence of various excitation methods on the efficiency of generation maximally entangled states will be discussed.

Abstract: A quantum witness attempts to classify observations or experimental outcomes as arising from one of two possible classes of physical theories: those described by macrorealism, and those that are not (e.g., quantum theory). While many notions of what makes something macroscopic exist, here we take a practical approach of increasing the number of qubits contributing to the witness, and maximizing the `disconnectivity’ (in the form of the entanglement) between said qubits. In this regard we experimentally implement a quantum witness on a set of small cat states (two-qubit entangled states) and large cat states (GHZ states with qubit number n = 4 and 6) using the IBM quantum experience.Our results show that the small cat states and four-qubit GHZ state are non-macrorealistic. In contrast, a six-qubit GHZ state does not violate the witness beyond a so called measurement invasiveness test, and thus might be understood in macrorealistic terms. As a comparison, we also consider un-entangled superposition states with n = 2, 3, 4, and 6 qubits, in which the disconnectivity is low.

Abstract: Quantum information scrambling describes the delocalization of local information to entanglement throughout all possible degrees of freedom. A well-known scrambling witness is the so-called out-of-time-ordered correllator (OTOC). The important insight of OTOC is that it is closely related to the incompatibility of two separate operators at two different times. In this work, we show that quantum scrambling can be witnessed in the context of temporal quantum steering. The essential point relies on the connection between Choi-Jamiolkowski isomorphism and the pseudo-density matrix formalism used in temporal quantum correlations. Based on this relation, we propose a scrambling quantifier, −T₃, according to an extended temporal steering scenario. We prove that −T₃ is monogamous, and when the channel is non-interacting (non-scrambled), −T₃=0.

Abstract: The phase control of coherence, entanglement and quantum steering will be discussed for an optomechanical system composed of a single mode cavity containing a partially transmitting dielectric membrane and driven by short laser pulses. The membrane divides the cavity into two mutually coupled optomechanical cavities resulting in an effective three-mode closed loop system, two field modes of the two cavities and a mechanical mode representing the oscillating membrane. The closed loop in the coupling creates interfering channels which depend on the relative phase of the coupling strengths of the field modes to the mechanical mode. For example, populations and correlations of the output modes show several interesting phase dependent effects such as reversible population transfer from one field mode to the other, creation of collective modes, and induced coherence without induced emission. The inseparability criterion for the output modes will be also investigated and we will show that entanglement may occur only between the field modes and the mechanical mode. We find that depending on the phase, the field modes can act on the mechanical mode collectively or individually resulting, respectively, in tripartite or bipartite entanglement. In addition, we will examine the phase sensitivity of quantum steering of the mechanical mode by the field modes. Deterministic phase transfer of the steering from bipartite to collective is predicted and optimum steering corresponding to perfect EPR state can be achieved.

Abstract: Quantum steering is the ability to remotely prepare different quantum states by using entangled pairs as a resource. In this talk, I will introduce a natural temporal analog of the EPR steering when considering measurements on a single object at different times. I will also give nontrivial operational meaning to violations of the temporal steering inequality by showing that it is connected to the security bound in the Bennett-Brassard 1984 protocol. Moreover, I will show that the temporal steering can be measured, via semidefinite programing, with a temporal steerable weight, in direct analogy to the proposed EPR steerable weight. Finally, I will demonstrate that the temporal steering can be experimentally verified on IBM Q.

Abstract: Multi-qubits systems can exhibit various correlations, classical and quantum, which are subject of intensive studies. Quantum correlations in multi-qubit systems are subject of intensive studies. Probably the most popular measure of quantum correlations is entanglement, but there are other measures that have been introduced and studied, such as quantum discord, geometric quantum discord, measurement induced disturbance and others. The simplest bipartite system in which the correlations can be studied is a system of two qubits, or two two-level atoms. In case of two-level atoms interacting with the reservoir of electromagnetic field modes in the vacuum, the evolution of the system can be described by the well known Lehmberg-Agarwal master equations. The collective evolution of the two-atom system depends on two collective parameters: collective damping 12 and dipole-dipole interaction 12, which both depend on the interatomic distance. Such a system is a good testing ground for studying evolution of quantum correlations. In my talk, I want to give some results dealing with collective effects in a system of three- atoms. Such a system is more difficult to describe because, for mixed states, we deal with 8×8 matrix which leads to 63 equations, and, what is even worse, there are no formulas to calculate concurrence, even if we know all the matrix elements. However, if we forget about damping, The Hamiltonian of the system can be diagonalized leading to pure eigenstates of the system including the dipole-dipole interaction. It is possible to calculate concurrence and negativity for such states, which gives some information on collective effects in the system. When the collective damping is included, evolution of the system is governed by the ma- ster equation which can be solved numerically for the matrix elements of the density matrix (analytical solution is possible but it is too complicated to be useful). It allows to calculate evolution of the negativity for different initial states. We have found, in particular, the so called monogamy relations for negativity, for chosen initial states of the system. It was shown that for some initial states the monogamy relations are violated.

Abstract: Waves in the spatio-spectral and -temporal coherence of evolving ultra-intense twin beams are predicted [1]: Twin beams with low intensities attain maximal coherence in the beam center until certain threshold intensity is reached. Then the area of maximal coherence moves with increasing intensity from the beam center towards its edges leaving the beam center with low coherence (the first coherence wave). For even larger intensities, a new coherence maximum is gradually built in the beam center with the increasing intensity [2] and, later, it again moves towards the beam edges forming the second coherence wave. Rotationally-symmetric twin beams are analyzed within a three-dimensional model that couples spectral and spatial degrees of freedom. Relation between the twin-beam coherence and its local density of modes during the nonlinear evolution is discussed.
 
[1] J. Perina Jr.: Waves in spatio-spectral and -temporal coherence of evolving ultra-intense twin beams, Sci. Rep. 9, 4256 (2019).
[2] J. Perina Jr.: Spatial, spectral and temporal coherence of ultra-intense twin beams, Phys. Rev. A 93, 013852 (2016).

Abstract: Interferometer is a complex device frequently used in experimental proof-of-principle setups for research using optical methods. In this talk several constructions will be presented and basic parameters discussed in the context of our recent research.

Abstract: The talk will focus on experimental implementation of a machine-learned quantum gate. The goal was to learn the gate to perform optimal phase-covariant cloning by means of reinforcement learning. This experiment demonstrates present-day feasibility and practical applicability of the hybrid machine learning approach.

Abstract: Weak values are traditionally obtained using a weak interaction between the measured system and a pointer state. It has, however, been pointed out that weak coupling can be replaced by a carefully tailored strong interaction. This talk is about a direct comparison of two strong interaction-based approaches (strong interaction accompanied by either a suitably prepared pointer state or quantum erasure) and the traditional weak interaction-based method on the platform of linear optics.

Abstract: Is it possible to implement practical quantum machine learning? Here we answer this question by implementing first all-optical setup that implements a kernel-based supervised quantum machine learning for three standard two-dimensional classification problems. In contrast to distance-based quantum machine learning, we need only to perform projective measurements on specially designed quantum states that efficiently encode the training data set. Our experiment is a two-photon implementation of a recent proposal of Schuld and Killoran [Phys. Rev. Lett. 122 040504 (2019)], where instead of continuous variables we implement variable spread kernels by varying the number of photons used in feature mapping circuit.

Abstract: A general model of unitary parameter estimation in presence of Markovian noise is considered, where the parameter to be estimated is associated with the Hamiltonian part of the dynamics. In absence of noise, unitary parameter can be estimated with precision scaling as 1/T, where T is the total probing time. A simple algebraic condition involving solely the operators appearing in the quantum Master equation, decides whether 1/T or 1/√T scaling of precision is achievable using the most general adaptive quantum estimation strategies including quantum error-correction protocols.

Abstract: Contextuality is a more general notion than nonlocality, since it also applies to measurements done in a single laboratory on a local system. In majority of scenarios one considers measurements done on a single particle and there are many proofs showing that these measurements do not admit a classical description in terms of noncontextual hidden-variable theories. However, the situation might be different if one performs collective measurements on many particles. In particular, what happens if one considers many indistinguishable particles? I am going to show that indistinguishability affects our ability to observe contextuality. Moreover, I will show that this approach allows one to resolve the problem of Bell inequality violations with classical light.
 
[1] “Contextuality of identical particles”, P. Kurzyński, Phys. Rev. A 95, 012133 (2017)
[2] “From contextuality of a single photon to realism of an electromagnetic wave”, M. Markiewicz, D. Kaszlikowski, P. Kurzyński, A. Wójcik, npj Quantum Information 5, 5 (2019).

Abstract: The states of a system of identical particles are required to be symmetric for bosons and antisymmetric for fermions. Are these inherent correlations just a mathematical artifact or can they be treated as a resource? In the talk I will support the latter point of view by showing how operationally accessible entanglement can be extracted form the indistinguishability of particles. I will focus on a recently proposed method [1] based on tailored single-photon subtractions from multiboson states.
 
  [1] M. Karczewski et al., “Sculpting out quantum correlations with bosonic subtraction.” Phys. Rev. A 100, 033828 (2019).

Abstract: A many-body system made of an even number of fermionic constituents can collectively behave in a bosonic way. The simplest example of such systems is the one made of two fermions. In fact, this is example was heavily studied so far, and it is unanimously accepted that entanglement plays a crucial role behind the bosonic quality of its collective behaviour. However, if we consider four fermions, they can behave like two bipartite bosons or further assemble into a single four-partite bosonic molecule. In general, 2N fermions can take many possible arrangements which might be treated as composite bosons. In this talk, I will aim to answer the question: what determines which fermionic arrangement is going to be realized in a given situation and can such arrangement be considered truly bosonic? I will discuss an entanglement-based method to assess bosonic quality of fermionic arrangements and apply it to study how the ground state of the extended one-dimensional Hubbard model changes as the strength of intra-particle interactions increases.
 
Ässembly of 2N entangled fermions into multipartite composite bosons” Zakarya Lasmar, P. Alexander Bouvrie, Adam S. Sajna, Malte C. Tichy, and Paweł Kurzyński Phys. Rev. A 100, 032105 (2019)

Abstract: The talk touches on the definition of Hilbert-Schmidt distance and its translation to measurable observables. Further it discusses the experimental implementation on the platform of linear optics. The reasons and benefits of measuring the Hilbert-Schmidt distance.

Abstract: We use our experimental setup, which is capable to generate three-qubit GHZ states with high repetition rate. With this setup we decided to test Hardy’s paradox and to measure nonlocal volume of the generated GHZ states.

Abstract: Recently, the group led by Gerhard Rempe has demonstrated experimentally two-photon blockade in a driven nonlinear system (composed of a harmonic cavity with a driven atom). Inspired by this experiment, we show that two-photon blockade can be generated in a driven harmonic cavity without an atom or any other kind of nonlinearity, but instead coupled to a nonlinear reservoir. We also investigate the possibility of generating other nonstandard types of photon-blockade and photon-induced tunneling.

Abstract: The talk presents the concept of a programmable controlled-phase gate and its linear-optical scheme. Usefulness of this gate is discussed in the context of quantum machine learning and quantum communications. Finally, the talk briefly outlines the currently ongoing experimental implementation of this gate on the platform of linear optics.

Abstract: Metasurfaces based devices are widely in fashion and metasurface become one of the promising platforms for photonics devices. It has been explored for various photonics applications such as light guiding, color filter design [1, 3]. Current research based on metasurfaces is mostly dependent upon either independent amplitude control or independent phase control mechanism. To explore the further capability of metasurfaces, it is important to have independent and simultaneous control on amplitude, phase, polarisation, and, the optical impedance of the wave [2]. In this talk, I am going to explain about independent amplitude and independent phase control of metasurfaces based on Pancharatnam-Berry (PB) phase mechanism. The technique is used to design the complete 4f system based on metasurface for parallel computing especially, spatial filtering purposes. It has high potential to design the neural network front-end to performed fast and parallel convolution operation which is difficult and time-consuming in the electronic domain platform.
 
[1] Patrice Genevet, Federico Capasso, Francesco Aieta, Mohammadreza Khorasaninejad, and Robert Devlin. Recent advances in planar optics: from plasmonic to dielectric metasurfaces. Optica, 4(1):139–152, 2017.
[2] Adam C Overvig, Sajan Shrestha, Stephanie C Malek, Ming Lu, Aarton Stein, Changxi Zheng, and Nanfang Yu. Dielectric metasurfaces for complete and independent control of optical amplitude and phase. arXiv preprint arXiv:1903.00578, 2019.
[3] Vishal Vashistha, Gayatri Vaidya, Ravi S Hegde, Andriy E Serebryannikov, Nicolas Bonod, and Maciej Krawczyk. All-dielectric metasurfaces based on cross-shaped resonators for color pixels with extended gamut. ACS photonics, 4(5):1076–1082, 2017.

Addresses:
(1) Ulyanovsk State University, Ulyanovsk, Russia
(2) Lab-STICC (UMR 6285), CNRS, ENIB, 29238 Brest Cedex 3, France
(3) Donetsk Institute for Physics and Engineering of the National Academy of Sciences of Ukraine
(4) V. N. Karazin Kharkiv National University, 61022 Kharkiv, Ukraine

Abstract: We study the transmittivity spectra of one-dimensional finite three-periodic photonic crystals of the structure [(ab)^N(cd)^M]^K composed of four different layers a, b, c, d being dielectric oxides Al₂O₃, SiO₂, TiO₂, and ZrO₂. We analyze modification of the transmittivity spectra of near-infrared electromagnetic waves of the TE and TM polarizations in the vicinity of the photonic band gaps with variations of the sub-cell numbers N and M and super-cell number K, the incidence angle, and the order of the layers in the structure. We propose classification of three-periodic photonic crystals by the magnitude and sign of the optical contrast between the layers in pairs (ab) and (cd) forming the sub-cells and discuss common spectral properties as well as their differences in these structures [1].
 
[1] I. S. Panyaev, L. R. Yafarova, D. G. Sannikov, N. N. Dadoenkova, Y. S. Dadoenkova, and I. L. Lyubchanskii. J. Appl. Phys. 126 , 103102 (2019).

Abstract: I will review the theory of “conventional” quantum sensors as quantum channels of information between the quantity (classical field) to be sensed and the measurement outcomes. The Shannon mutual information and the Fisher information may be used as metrics for the quality of a quantum sensor [1]. Next, I will briefly describe non-ideal quantum sensors, which perform non-unitary transformations on the input quantum state. The theory of non-ideal quantum sensors is relevant to experiments because the input quantum state may have errors, there may be scattering (decoherence and dispersion) in the quantum channel, and the output state detectors may not be ideal [2,3]. Next, I will introduce simple 1-qubit and 2-qubit models of a quantum sensor that have an analogy with topological energy band theory [4]. In preparation, I review some topological concepts such as Berry curvature and the Quantum Geometric Tensor. I will suggest that a new class of quantum sensors called “topological quantum sensors” may be realizable. Finally, I will give a detailed example of a topological quantum sensor of magnetic fields based on the dynamical quantum Hall effect [5].
 
1. T. B. Bahder and P. A. Lopata, “Fidelity of quantum interferometers”, Rev. A 74, 051801(R) (2006).
2. D. S. Simon, A. V. Sergienko, and T. B. Bahder, “Dispersion and fidelity in quantum interferometry”, Phys. Rev. A 78, 053829 (2008).
3. T. B. Bahder, “Phase estimation with nonunitary interferometers: Information as a metric’’, Phys. Rev. A 83, 053601 (2011).
4. A. Bansil, H. Lin, and T. Das, “Colloquium: Topological Band Theory”, Rev. Mod. Phys. 88, 021004 (2016).
5. V. Gritsev and A. Polkovnikov, PNAS (Proceedings of the National Academy of Sciences U. S.) 109, 6457 (2012).

Abstract: The headquarters of the Army Research Office (ARO) is located in Raleigh-Durham, North Carolina, USA. The ARO funds excellent basic research in the sciences. In fact, ARO has funded numerous Nobel laureates over the years. The majority of ARO funding goes to U.S. researchers. However, two years ago, the ARO has started an International Program. I am the Program Manager for the International Program in Physics. My geographical area is the whole world, excluding the continental U.S. (which is covered by other ARO program managers in the U.S.). My goal is to find exceptional basic physics research that is done outside of the continental U.S. My Program is called “Quantum Scale Materials”, and it deals with a broad area of quantum physics, including topological physics, quantum sensors, and a variety of other quantum-related physics. My office is in the Roppongi district of Tokyo, Japan. In this talk, I will give an overview of the ARO organization, the International Program, and the Physics Division. I will describe the goals of the ARO International Program in Physics in Asia-Pacific. Finally, I will describe the process of submitting a research proposal to ARO.

Abstract: A space-time algebra incorporating a sharpening of the principle of relativity allows all four Maxwell equations to be written in a particularly simple and elegant way as dF=0, where dF is the four-vector differential of the electromagnetic field. Defining the new two component rest mass as M second order equations such as d(d(F+M))=0 lead to four new equations coupling intrinsic spin and 4-current (Williamson, IOP conf. 2019). The result leads to an explicit, dynamical interaction between mass and field, through current and intrinsic spin, confining each with respect to the other. The resulting new quantised solutions over and above the photon ones correspond to fermionic vortices in momentum space. These are necessarily charged and have an intrinsic 720 degree symmetry. They are physical mass-field spinors. There are four and only four such solutions, distinguished from each other by the charge and spin signs. The charge may be calculated, and gives a value close to the elementary charge. The four new solutions are identified with the spin up and down electron and positron. The theory throws light in the way electrons behave from being point-like in ultra high energy collisions, to becoming quantum-mechanically extended in the solid state with size scales of tens of nanometers (Williamson et. al. Phys Rev, 1990). The new theory therefore allows hitherto unprecedented insights into the design, development and properties of new quantum materials and devices.

Biography: John Williamson worked at CERN for seven years, in the advanced theoretical and experimental physics group in Philips for five years, and in the College of Science and Engineering in Glasgow University for 27 years. He is currently leading an international research group, the quicycle (quantum bicycle) society. He has published widely in the fields of elementary particle physics, quantum transport in nanoelectronics, and in quantum field theory. He has (co-)authored over a hundred papers. He has an h-index of 45 and over twelve thousand citations.

Abstract: Investigation of many-body spin systems in cQED (Cavity quantum electrodynamics) enable applications of quantum simulators with superconducting quantum circuits. In our work, we perform experimental studies of time-resolved spin dynamic of superconducting qubit arrays embedded into a superconducting resonator. We use the superconducting qubit arrays for the demonstration of an occurrence of quasi-periodic many-body Rabi oscillations and complex spin dynamics in the dispersion and the resonance regimes with tunable interaction strengths between the qubits and the cavity. In particular, we experimentally explore a possibility to realize a time crystalline order in an array of superconducting qubits embedded in a superconducting resonator by applying periodic sequence of microwave pulses with excitation of nonequilibrium states in the system. Focusing on time crystals consisting of a small number of artificial atoms, we attempted to show the microscopic processes responsible for the appearance of the time crystalline order parameter.

Streszczenie: Umiejętność kontrolowania lokalnych zmian właściwości magnetycznych w heterostrukturach magnetycznych cieszy się zainteresowaniem badaczy zarówno ze względu na badania podstawowe materiałów, jak również na potencjalnie szerokie zastosowanie układów o modulowanych właściwościach magnetycznych. Lokalną zmianę anizotropii magnetycznej można uzyskać poprzez zastosowanie strukturyzowanego bufora, który wymusza przestrzenną modulację magnetycznych właściwości w osadzonej na jego powierzchni ciągłej warstwie Co [1]. Innym przykładem manipulacji parametrami magnetycznymi heterostruktury jest jej lokalne naświetlanie wiązką jonów bądź lasera. Zmiana parametrów naświetlania, tj. zmiana typu jonów czy natężenia wiązki, jak również zmiana struktury próbki (jak np. grubość warstwy wierzchniej), wpływa na kierunek namagnesowania warstwy Co o określonej grubości [2,3]. Co więcej, naświetlanie układu Pt/Co/Pt jonami Ga+ w formie równoległych pasków można wykorzystać do stworzenia jednowymiarowej, periodycznej magnetycznie struktury, o zmiennym kierunku namagnesowania. Nasze wyniki pokazują także, że w układzie Co/Mo/Co naświetlanie jonami Ga+ zmienia typ oddziaływania między magnetycznymi warstwami. Przełączenie jest zależne od referencyjnego (nienaświetlonego) stanu i dobranych parametrów padającej wiązki jonów. W szczególności, możliwym jest uzyskanie zmiany sprzężenia międzywarstwowego z anty-równoległego na równoległe. Periodyczna zmiana takich sprzężeń może być rozpatrywana jako dwuwarstwowy (dwukanałowy) kryształ magnoniczny. Innym sposobem wprowadzenia periodycznych zmian właściwości magnetycznych jest wytworzenie jednowymiarowych kryształów przez manipulację ich strukturą domenową. Oscylujący kierunek namagnesowania tworzy się np. w układach wielowarstwowych typu W/Co/Pt. Początkowo labiryntowa struktura domenowa może być przeformowana do równoległych paskowych struktur przez zastosowanie odpowiedniej procedury rozmagnesowania. Badany układ wielowarstwowy powinien wykazywać silne oddziaływanie iDMI, które jest przedmiotem dalszych badań. W periodycznych układach wytworzonych omawianymi sposobami propagacja fal spinowych powinna być kontrolowalna i charakteryzować się odmienną strukturą pasmową względem jednorodnego magnetycznie ośrodka. Praca jest realizowana w ramach programu POWROTY 2017 Fundacji na rzecz Nauki Polskiej współfinansowanego przez Unię Europejską z Europejskiego Funduszu Rozwoju Regionalnego.
 
[1] A. Wawro, E. Sieczkowska, A. Petroutchik, L.T. Baczewski, Z. Kurant, and A. Maziewski, Local variation of ultrathin Co film magnetization orientation induced by a structured buffer: Magnetic dots, Phys. Rev. B 83, 092405 (2011).
[2] A. Maziewski, P. Mazalski, Z. Kurant, M. O. Liedke, J. McCord, J. Fassbender, J. Ferré, A. Mougin, A. Wawro, L. T. Baczewski, A. Rogalev, F. Wilhelm, and T. Gemming, Tailoring of magnetism in Pt/Co/Pt ultrathin films by ion irradiation, Phys. Rev. B 85, 054427 (2012).
[3] M. M. Jakubowski, M. O. Liedke, M. Butterling, E. Dynowska, I. Sveklo, E. Milińska, Z. Kurant, R. Böttger, J. von Borany, A. Maziewski, A. Wagner and A. Wawro “On defects role in enhanced perpendicular magnetic anisotropy in Pt/Co/Pt, induced by ion irradiation,” J. Phys. Condens. Matter, (2019).

Streszczenie: Ultracienkie układy Pt/Co/Pt naświetlano pojedynczymi impulsami lasera femtosekundowego. W miejscu naświetlania próbka uległa rozmagnesowaniu. Wykorzystując mikroskopię sił magnetycznych (MFM) zaobserwowano powstanie domen magnetycznych o sub-mikronowych rozmiarach. Proces rozmagnesowania poprzez naświetlania impulsami światła był całkowicie odwracalny. Scharakteryzowano warunki, w których możliwe jest wystąpienie takiego rozmagnesowania – gęstość energii impulsu musi być większa od pewnej progowej wartości, która zależy od anizotropii magnetycznej. Proces tworzenia domen magnetycznych i jego termiczna natura znajdują potwierdzenie w wynikach symulacji mikromagnetycznych, wykorzystujących równanie Landaua-Lifshitza-Blocha. Przedstawione zostaną również wyniki modelowania mikromagnetycznego rozkładów magnetyzacji z wykorzystaniem oddziaływania Działoszyńskiego-Moriyi.

Abstract: Low-energy eigenmode excitations of magnetically ordered systems are spin waves that can be quantified by quasiparticles termed magnons. Magnons can be thermally and non-thermally excited, confined, spectrally shaped, and guided by material design [1]. Magnonic currents are routinely generated at low energy cost and do not suffer from Ohmic losses, which make them an attractive medium for communication, and processing of information. Here we present topologically non-trivial (spatially structured) magnons that carry a definite and electrically tunable projection of the orbital angular momentum constituting onto the propagation direction. Such beams we term helical or ”twisted magnon beams” [2]. Starting from fundamental equations for spin dynamics we discuss how twsited beams emerge in magnonic waveguides and how to topologically quantify and steer them. A key finding is that the topological charge associated with the twist of a particular beam is tunable externally and protected against damping in a ferromagnetic system. Coupling to an external electric field via the Aharanov-Casher effect allows for electrical tuning of the topological charge. This renders possible twist-based robust, low-energy consuming multiplex magnonic computing, analogously to using photonic orbital angular momentum in optical communications [3], but here at shorter wavelength and lower energy consumption, and ready integration in magnonic circuits utilizing the versatile toolbox for material and spin waves engineering. Both ferro- and antiferromagnetic magnons will be discussed.

  [1] Chumak, A. V. et al., Nature Physics 11, 453 (2015).
  [2] Jia, C.L. et al., Nat. Comm. 10, 1 (2019).
  [3] Willner, A. E. et al., Adv. Opt. Photon. 7, 66 (2015).

Abstract: To enable organic solar cells with a competent charge transport efficiency, reducing the thickness of active layer without sacrificing light absorption efficiency turns out to be of high feasibility. Herein, organic solar cells on wrinkled metal surface are designed. This structure could improve light capture, mitigate defect recombination and benefits charge transport and collection. Besides, we found that transport layer modification and doping could benefit charge extraction of the organic solar cells. A flexible organic solar cell was also fabricated with our optimized materials. For perovskite solar cells, we found that 20% Cs and 10% Cl were beneficial for structural, morphological, opto-electronic and photovoltaic properties. Besides, perovskite with additives of DRCN5T, MACl and MAH₂PO₂ presents improved morphological and charge dynamic properties. A 25.4%-efficient monolithic perovskite/Si tandem solar cell was also obtained.

Abstract: A central goal of nanotechnology is the precise synthesis of nanostructures with optimized functionalities. The functionalities of nanostructures are controlled by external stimuli such as pulses of light, current or heat. This brings up the question: what is the connection between nonequilibrium conditions and structural stability at the nanoscale? To answer this question, we employ femtosecond electron diffraction [1] to study ultrafast energy flow and structural changes in heterostructures of size-selected Au923 nanoclusters, or Au nanoislands, on semiconducting thin-films. Au923 nanoclusters are found to exhibit ultrafast surface premelting at atypically low lattice temperatures and pronounced electron-lattice nonequilibrium conditions [2]. Furthermore, the phonons of a crystalline substrate (graphene) scatter on the adsorbed Au923 nanoclusters and induce nanocluster-rotations at picosecond timescales [3]. Finally, surface decoration with plasmonic, quasi-2D Au nanoislands sensitizes the semiconducting WSe2 to sub-band-gap photons and accelerates its electron-phonon equilibration times. All the above phenomena are considered important for the stability of nano-catalysts and the efficiency of plasmonic solar cells. This research stemmed from an international collaboration between the research group Structural Electronic Surface Dynamics headed by Ralph Ernstorfer (FHI Berlin) and the groups of Richard Palmer (Swansea University in UK), Laurenz Rettig (FHI Berlin), Vlasios Mavrantzas (ETH Zurich and University of Patras) and Stephanie Reich (Free University of Berlin).

[1] Lutz Waldecker et al., Journal of Applied Physics 117, 044903 (2015).
[2] Thomas Vasileiadis et al., ACS Nano 12 (8), 7710-7720 (2018).
[3] Thomas Vasileiadis et al., Nanoscale Horizons (2019).

Addresses:
(1) Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan
(2) Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
(3) Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
(4) School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
(5) Physics Department, University of Michigan, Ann Arbor, Michigan 48109-1040, USA

Abstract: The characterization, explanation, and quantification of quantumness, in particular the discrimination from classicality in terms of classical strategies, lie at the heart of quantum physics. Recently, it is shown that dynamical processes can exhibit classical or nonclassical traits, depending on the nature of the system-environment correlations and the related (im)possibility to simulate these dynamics with Hamiltonian ensembles – the classical strategy. Here we propose to extend this classification towards quantifying the nonclassicality. In the spirit of Wigner function, we generalize Hamiltonian ensembles to encompass quasi-probability distributions comprising negative values. Based on Lie algebra representations, Fourier transforms on groups, and root space decompositions, we demonstrate that quasi-probability distributions are faithful representations of pure dephasing dynamics; moreover, we show how to retrieve these quasi-probability distributions. This allows us to quantify process-nonclassicality time-independently, in terms of the deviations of the corresponding quasi-probability distributions from legitimate (non-negative) probability distributions.

Abstract: NCPS Solaris is a modern, low emittance synchrotron radiation source based on the storage ring (1.5 GeV) built in Double-Bend Achromat technology. The facility since 2017 is open for users, and currently offering two beamlines – ultra angle-resolved photoemission spectroscopy (UARPES) and PEEM/XAS. Next two beamlines (XMCD and XPS) are in construction or installation phase. The plans for the development of the NCPS include the construction of further beamlines. Currently, in cooperation with JINR Dubna, the design works for a modern beamline – SOLCRYS, dedicated for diffraction studies and small-angle X-ray scattering have been initiated. SOLCRYS beamline will utilize a superconducting multipole 4-Tesla wiggler as the efficient X-ray source (up to 25 keV). The synchrotron radiation beam from the source will be divided into two independent branches. During the seminar the details of the project and recent results of numerical simulations of X-ray optics for both branches, carried out using the ray-tracing method will be presented.

Abstract: Majority rule is a ubiquitous principle of collective decision making in social animals from bee to human. Despite its apparent simplicity, there are many paradoxical phenomena in democratic majority rule, such as the persistence of powerful dominating minority and majority-assisting function of contrarian opponents. In this talk, I introduce “opinion dynamics”, which has been developed in search of a mathematical model describing the realistic features of majority rule. We detail its structure, mathematical properties and predictions.
Ref: arXiv:1901.09622 . Slides for the talk are here. 

Abstract: The quantum graph is a concept describing a system of quantum particles on graphs made up of lines and vertices. It is a mathematical and solvable model of nano wire-based and quantum dot-based single-electron devices. We point out the existence of several intriguing nontrivial features of quantum graphs such as threshold resonance and controlled spectral filtering of quantum flux, and discuss their application in modeling and designing of quantum devices.
Ref: arXiv:1203.6555 . Slides for the talk are here. 

Abstract: The superconducting proximity effect induced in materials in close contact with a superconductor is well established. We reveal that similarly the topologically protected surface states recently found on the surfaces of special crystals can leak into appropriate adjoining materials. We bring these two effects into proximity and study how superconductivity and topologically protected surface states interact with each other, a situation of interest in the search for Majorana bound states. We look at the scanning tunneling microscopy of a large topological insulator with superconducting islands deposited on the surface, and analyze theoretical models which capture the hybridization between the topological surface states and the superconducting states. The density of states of both the topological insulator and the superconductor turn out to exhibit interesting proximity effects and open up new possibilities for observing Majoranas.

Abstract: The Falicov-Kimball model [1] is a simplified version of the Hubbard model [2], where only electrons with, e.g., spin down are itinerant and the other are localized. During the seminar, we will discuss results for the extended Falicov-Kimball model at half-filling on the Bethe lattice in the limit of large dimensions derived within the DMFT formalism [3-7], which is a rigorous approach in this limit. The on-site and the intersite density-density interactions between particles occupying neighboring sites are included in the hamiltonian [5-7]. We determined the exact phase diagrams of the model both in the ground state [6] and at finite temperatures [7]. Using analytical formulas we showed that in the ground state the system is an insulator for any non-zero values of the interaction couplings and we detected the discontinuous transition between two different charge-ordered phases [6]. The finite temperature diagrams are a generalization of the diagram previously obtained in Ref. [4] for the standard Falicov-Kimball model, but they are much richer than it. In particular, it turns out that these diagrams contain more types of ordered phases, both conductive and insulating, and phase transitions between them are either continuous or discontinuous [7]. What is more, it turns out that in a certain range of interaction parameters the order-disorder phase transition may be discontinuous.

[1] L.M. Falicov, J.C. Kimball, Phys. Rev. Lett. 22, 997 (1969); R. Ramirez, L.M. Falicov, J.C. Kimball, Phys. Rev. B 2, 3383 (1970).
[2] J. Hubbard, Proc. R. Soc. London, Ser. A 276, 238 (1963).
[3] J.K. Freericks, V. Zlatic, Rev. Mod. Phys. 75, 1333 (2003); A. Georges, G. Kotliar, W. Krauth, M.J. Rozenberg, Rev. Mod. Phys. 68, 13 (1996).
[4] R. Lemański, K. Ziegler, Phys. Rev. B 89, 075104 (2014); S.R. Hassan, H.R. Krishnamurthy, Phys. Rev. B 76, 205109 (2007).
[5] P.G.J. van Dongen, D. Vollhardt, Phys. Rev. Lett. 65, 1663 (1990); P.G.J. van Dongen, Phys. Rev. B 45, 2267 (1992).
[6] R. Lemański, K.J. Kapcia, S. Robaszkiewicz, Phys. Rev B 96, 205102 (2017).
[7] K.J. Kapcia, R. Lemański, S. Robaszkiewicz, preprint, arXiv: 1903.08092 (2019).

Abstract: I will present the results of observations (including those with PST2/RBT) of a gamma-ray burst (GRB) 171205A and the associated supernova (SN) 2017iuk, which led to the discovery of a hot gas cocoon. This was possible because observations started very early and the jet emission was weak. This gives support to the theoretical models of GRB/SN explosions, which predicted the existence of such a cocoon. This discovery opens the possibility to study internal processes during explosions of very massive stars, and hence will shed light on the understanding of the production of heavy elements.

Abstract: In this talk, I review our recent experiments on utilization of pure spin currents created by the spin-Hall effect and the nonlocal spin injection for excitation and manipulation of coherent propagating spin waves in magnonic nano-structures based on metallic and insulating magnetic films. I show that spin currents enable novel functionalities of magnonic devices not achievable by using traditional approaches. In particular, spin currents allow highly efficient excitation of continuous spin waves and short spin-wave packets with the duration down to a few nanoseconds exhibiting nonlinear self-stabilization during propagation. These demonstrations open a route for implementation of high-speed magnonic devices characterized by high information flow capacity.

[1] V. E. Demidov et al., Nat. Commun. 7, 10446 (2016).
[2] V. E. Demidov et al., Phys. Rep. 673, 1 (2017).
[3] B. Divinskiy et al., Adv. Mater. 30, 1802837 (2018).
[4] M. Evelt et al., Phys. Rev. Appl. 10, 041002 (2018).

Abstract: Spin-orbit interaction leads to the mixing of orbital and spin degrees of freedom and is responsible for a variety of spin and transport phenomena such as anisotropic magnetoresistance, anomalous and spin Hall effects, non-equilibrium spin polarization and spin-orbit torques. Recently under special attention are two non-equilibrium effects responsible for the efficient spin-to-charge conversion: the spin Hall effect and current-induced spin polarization. Both of them opens a unique possibility of pure electrical control of the spin degree of freedom and have been already used as an effective tool for the generation and detection of spin currents and the so-called spin-orbit torques. The physics that stands behind such effects is very rich and depends on the nature of spin-orbit coupling in the host material. Importantly, the spin-orbital effects are strongly enhanced in low-dimensional structures where the lack of inversion symmetry leads to large Rashba effect. Thus, the natural platforms for spin-orbitronics are the interfaces of semiconductor heterostructures, surfaces of topological insulators, two-dimensional van der Waals heterostructures, and perovskite-oxides heterointerfaces.

During this seminar, I will discuss and summarize results that I obtained within the research on spin-to-charge conversion in semiconductor heterostructures and graphene-like hybrid structures. I will focus on the behaviour of spin Nernst and spin Hall effect beyond the zero-temperature limit in a two-dimensional electron gas that might appear in semiconductor heterostructures. Next, I will summarize the properties of anomalous, spin and valley Hall effects in graphene-based hybrid structures. Then, I will present results obtained for electrically and thermally induced non-equilibrium spin polarization in such systems. During the presentation, I will mention about such aspects as the interplay between effective exchange field and spin-orbit interaction, and the role of a Berry phase in the system responses. In the last part of the seminar, I will also briefly discuss the fingerprints of spin-orbit driven phenomena in the magnetoresistance effects.

Streszczenie: W układach o niskiej wymiarowości mogą być indukowane stany związane o zerowej energii, zwane stanami Majorany [1]. Obecne eksperymenty, m.in. w układzie ferromagnetycznych atomów na powierzchni nadprzewodnika [2] lub nanostruktur hybrydowych półprzewodnik—nadprzewodnik [3], potwierdzają istnienie tych stanów. Ze względu na swoje topologiczne własności, wierzy się, że stany Majorany mogą być wykorzystane do budowy kwantowych komputerów. Podczas wystąpienia przedstawię wyniki eksperymentalne pokazujące realizację stanów związanych Majorany. Omówię podstawowe własności quasi-cząstek Majorany na przykładzie układzie kropki kwantowej połączonej z nanodrutem [4]. Ze względów praktycznych, istotne jest aby w sposób kontrolowany wytwarzać stany Majorany oraz w prosty sposób nimi manipulować – zaprezentuje w jaki sposób stany te mogą być ”wytwarzane” w układzie półprzewodnikowego nieopierścieniana z kropką kwantową [5] oraz układzie ultra-zimnych gazów fermionowe w pułapce optycznej [6].

[1] A. Y. Kitaev, Phys.—Usp. 44, 131(2001).
[2] S. Jeon, Y, Xie, J. Li, Z. Wang, B. A. Bernevig and A. Yazdani, Science 358, 772 (2017).
[3] V. Mourik, K. Zuo, S. M. Frolov, S. R. Plissard, E.P.A.M. Bakkers L.P. and Kouwenhoven, Science 336, 1003 (2012).
[4] A. Ptok, A. Kobiałka and T. Domański, Phys. Rev. B 96, 195430 (2017).
[5] A. Ptok, A. Cichy and T. Domański, J. Phys.: Condens. Matter 30, 355602 (2018).
[6] A. Kobiałka and A. Ptok, J. Phys.: Condens. Matter 31, 185302 (2019).

Abstract: The aim of the presented research was to investigate the GHz-THz phonon propagation in quasi two-dimensional materials of importance for future emerging applications by means of developed and dedicated experimental techniques. I have investigated several strategies to tailor the phonon dispersion and the phonon MFP. In particular, these were: spatial 1D confinement, periodic patterning, implementation of local resonances, static stress and dense grain boundaries. The key scientific questions which I have considered are summarized by the following objectives: (a) To determine the influence of spatial confinement and static stress on the hypersonic phonon propagation and intrinsic elastic properties for the crystalline ultra-thin membranes. (b) To investigate the breakdown of bulk elastic properties under 1D spatial confinement and with dense grain boundaries. (c) To investigate the role of sub-micrometer periodic repetition of motifs as holes and pillars in/on Si membranes in hypersonic phonon dispersion. (d) To investigate the reduction of the thermal conductivity and its temperature dependence in holey PnCs at high temperatures (300-1000 K). (e) To quantify air-mediated heat dissipation (losses) in holey PnCs. (f) To determine the role of the structure imperfection as the surface roughness, fabrication precision and intentional disorder on the coherent (wave-like) effects in membrane based PnCs.

Streszczenie: W badaniach sfrustrowanych układów izingowskich przyjmuje się, że jednym z istotnych efektów jest wysoka degeneracja stanu podstawowego. Podobnie w przypadku (skończonych) układów kwantowych O. Kahn podkreślał znaczenie degeneracji wprowadzając termin „degenerate frustration”. Synteza i badanie sfrustrowanych geometrycznie molekuł magnetycznych wskazało, że możliwe jest występowanie układów, w których frustracji geometrycznej nie towarzyszy degeneracja stanu podstawowego. Co więcej, nie jest to li tylko efekt skończoności układu (dyskretności widma hamiltonianu), gdyż w wielu przypadkach to zachowanie jest uniwersalne: nie zależy od rozmiaru układu (liczby spinów) i wartości momentów magnetycznych (liczb spinowych). W omawianych badaniach analizowane są trzy klasy molekuł tego typu. W każdym przypadku jako podstawowy rozpatrywany jest izotropowy model Heisenberga, a jednocześnie analizowane są jego analogi: model klasyczny i model Isinga. Każdy z tych modeli ma swoje specyficzne właściwości, jednak wspomniany powyżej efekt występuje we wszystkich trzech przypadkach.

Abstract: Magnetic skyrmions [1, 2] are topologically protected nanometer sized chiral spin textures with an out of plane magnetic domain at the center. Due to their various unique features such as stability given by their topology, they are considered as potential candidates for information carriers in next generation data storage devices, like racetrack memory. For such applications, it is crucial to be able to manipulate their current-induced motion in various directions. In this work, we present stable nanoscopic skyrmions confined by an array of antidots. Utilizing the induced periodic potential of the antidot lattice, we propose a method for unprecedented control of the skyrmion dynamics. But for that purpose it is also important to understand and control the damping in ferromagnetic thin films. One of the possible ways to manipulate magnetic damping is injection of spin current generated due to spin Hall effect [3] which is an emerging phenomenon where the properties of electrical charge current can be transferred to the electron’s intrinsic angular momentum (spin current), and vice versa. To measure the modulation of damping, we use a time-resolved magneto-optical Kerr effect microscope (TR-MOKE), which has the best spatial and temporal resolution to measure the damping of the ferromagnetic film. The observations will have a strong impact on the development of spintronics devices, such as spin transfer torque nano-oscillators or domain wall racetrack memories.
Acknowledgement: We acknowledge ETH Zurich Post Doctoral fellowship and Marie Curie actions for People COFUND program and Dr. S. Wintz, Dr. N. S. Bingham, Dr. A. K. Suszka and Mr. T. P. Dao for technical support and valuable discussions.
References:
[1] D. A. Gilbert et. al., Nat. Commun. 6, 8462 (2015).
[2] O. Boulle et. al., Nat. Nanotech. 11, 449 (2016).
[3] L. Liu et. Al., Science, 336, 555 (2012).

Abstract: Interactions of impurities with their environment govern many interesting quantum many-body phenomena in condensed matter systems, for example the Kondo effect. In particular, ultracold atoms provide an excellent platform for studying impurity physics due the precise control and independent tunability of experimental parameters. While impurities in single-orbital ultracold quantum gases have been studied, multi-orbital systems have not yet been explored. Fortunately, alkaline-earth(-like) atoms (AEAs), such as ytterbium and strontium, feature a metastable electronic state, which is long-lived and can be utilized as an orbital degree of freedom. This so-called clock state makes AEAs promising candidates for the implementation of two-orbital physics. In our experiment, we use fermionic ytterbium-173 to realize and probe impurities in two-orbital many-body systems.
First, I report on our recent efforts to implement Kondo physics in state-dependent optical lattices. We demonstrate orbital dependent mobility in these lattices and show that interorbital spin exchange, comparable to the coupling in the Kondo model, is present in this system.
Second, I discuss our most recent results on the observation of multi-orbital polarons in a two-dimensional Fermi gas. We precisely characterize these long-lived quasiparticles which are formed by mobile impurities interacting with a Fermi sea.

Abstract: Translational dynamics in soft-matter systems is related to spatial translations of atoms or molecules. Those translations can be accurately measured using Nuclear Magnetic Resonance spectroscopy given that the motion of nuclear spins is associated with a change of the magnetic field followed by a shift in the Larmor precession frequencies. We utilise the fact that the variations of the magnetic field can be either a feature of the system (local magnetic field inhomogeneities) or can be generated on purpose, using artificially created magnetic field gradient (spin labelling). In this talk, several unique applications of Nuclear Magnetic Resonance spectroscopy to translational dynamics problems in macromolecular and self-assembling systems will be presented. In particular, the following topics will be discussed: (a) self-diffusion studied for star-polymers in melt (¹H PGSE NMR), (b) real-time self-diffusion experiments based on the magnetization grating (¹H OUFIS single-shot diffusion NMR), (b) two-site proton hopping via hydrogen bonds upon aggregation of surfactants in aqueous solutions (¹H CPMG T₂ dispersion NMR), (c) an impact of interactions between BSA and Gemini surfactants on self-diffusion coefficients (¹H PGSE NMR), (d) an impact of aggregation of peptides on self-diffusion coefficients (¹H PGSE NMR), (e) concentration-dependent aggregation of Gemini surfactants observed via self-diffusion coefficients (¹H Bayesian-DOSY NMR), (f) peptides snorkeling in micellar environments and its impact on the internal translational dynamics of surfactants in micelles (³¹P CPMG T₂ dispersion NMR, ¹H/²H/³¹P PGSE NMR).

Streszczenie: Betalainy to betaksantyny i betacyjaniny stanowiące ważną grupę barwników naturalnych, występujących w roślinach z rzędu Caryophyllales, a także w niektórych grzybach wyższych. Naszym celem badawczym był opis właściwości fotofizycznych tych barwników na podstawie wyników czasowo-rozdzielczej spektroskopii absorpcji przejściowej w zakresie UV-vis-NIR. Wyznaczone czasy życia betalain w stanie S1 w roztworach wodnych i alkoholowych są krótkie (w przybliżeniu 10 ps u betacyjanin i 50 ps u betaksantyn w wodzie). Układ molekularny w stanie wzbudzonym S1 osiąga punkt przecięcia stożkowego na skutek zmiany geometrii wyrażonej poprzez obrót wokół centralnych wiązań C=C i C=N. Proces konwersji wewnętrznej S1→S0 zachodzi z wysoką wydajnością kwantową ( > 96%), co świadczy o wydajnej konwersji światła na ciepło i potwierdza fotoprotekcyjną rolę betalain w roślinach.
Drugi zakres badań dotyczył 3H-naftopiranów – związków wykazujących fotochromizm. Po raz pierwszy zastosowaliśmy czasowo-rozdzielczą spektroskopię w średniej podczerwieni do jednoznacznej identyfikacji form barwnych transoid-cis powstających w procesie fotochromowym.

Streszczenie: Koszty energii stale rosną i dlatego też prowadzi się wiele prac badawczych związanych z jej pozyskiwaniem ze źródeł odnawialnych oraz jej odzyskiwaniem (ang. energy harvesing). Termoelektryczne konwertery energii, zwane też termogeneratorami (TEG) są rozwiązaniem, które umożliwia wytworzenie energii elektrycznej z traconej energii cieplnej. Termogeneratory pracują w oparciu o powszechnie znane efekty: Seebecka, Thomsona i Peltiera i posiadają szereg zalet m.in. brak ruchomych części, brak wibracji, niezawodność i możliwość miniaturyzacji. Sprawność klasycznych TEG zależy przede wszystkim od przewodności termicznej i rezystywności elektrycznej materiałów, z których są one zrobione i jest ona niższa niż w przypadku innych typów konwersji energii [1]. Dlatego też prace badawcze koncentrują się przede wszystkim na poprawie figure of merit materiałów termoelektrycznych. Zbyt mała sprawność klasycznych TEG sprawiła, że obecnie trwają pracę nad rozwojem nowej generacji układów TEG opartych o konwertery magnetokaloryczne. Koncepcje zaprezentowane przez [2] są bardzo interesujące z punktu widzenia współczesnej elektroniki. Wprowadzenie spinowych koców termoelektrycznych [3] bezpośrednio do obudów układów elektronicznych może rozwiązać problem rosnącego wytwarzania ciepła w elementach elektronicznych. Zalety, takie jak bardzo małe rozmiary konwerterów magnetokalorycznych, możliwość ich miniaturyzacji, potencjalnie wyższy wskaźnik figure of merit w porównaniu do klasycznych TEG, czynią konwertery magnetokaloryczne bardzo interesującymi w kontekście wytwarzania energii elektrycznej z energii cieplnej. W niniejszej prezentacji omówione zostały współczesne rozwiązania związane z konwersją energii cieplnej na energię elektryczną. Zaprezentowano rozwój klasycznych TEG oraz prace badawcze związane z dalszym wzrostem ich efektywności. W dalszej części prezentacji omówione zostały termogeneratory działające w obszarze spin caloritronics oraz wykazano ich potencjalną przewagę nad klasycznymi rozwiązaniami.
[1] A. Shakouri, Annu. Rev. Mater. Res., 41, (2011), 399–431.
[2] A. A. Kovalev and Y. Tserkovnyak, Solid State Commun., 150, (2010), 500–504.
[3] A. Kirihara, et. al., Nat. Mater.,11, (2012), 686–689.

Abstract: Magnetization damping of polycrystalline thin films of the Co₂₅Fe₇₅ alloy was found to be very low reaching 1×10⁻³ and the intrinsic damping of this alloy is even lower achieving 5×10⁻⁴. Our study focuses on the influence of an adjacent layer on total damping. We found that only using Cu buffer we obtain low magnetization damping and we confirmed low value of intrinsic damping.

Abstract: Here we present multiferroic (ferromagnetic/ferroelectric) thin films of highly strained Bi(Fe0.5Mn0.5)O3 as the only known high-temperature magnetodielectric material with low Gilbert damping. We present the general functional properties of the material, as well as few previously unreported structural and functional properties. Finally, we will show the great potential of this perovskite for spintronic applications.

Abstract: Iron or nickel and their oxide nanoparticles have received considerable attention due to their applications in magnetic, electronic, pigmental, catalyst and biomedical purposes. NiO/Ni and Fe₃O₄/FeO composite particles were prepared by a pulsed laser irradiation of oxide nanoparticles dispersed in liquid. The sizes of particles and their composition were controlled by tuning the laser parameters, such as laser fluence and/or irradiation time. Correlation between structure of obtained composites and their magnetic properties will be presented.

Abstract: The thermal stability of ferromagnetic nanostructures is mostly determined by the height of the energy barrier between two micromagnetic configurations: a metastable state and the ground state. Few analytical models for the magnetization profile at the lowest barrier have been obtained. In this talk, I will present micromagnetic simulations perform to validate one of those cases: a model for magnetization reversal of ferromagnetic nanorings [1].
[1] Phys. Rev. B 73, 054413 (2006)

Abstract: Using spatial light interference of ultrafast laser pulses we impulsively generate a spatial modulation of the magnetization profile in an otherwise uniformly magnetized film, inducing the onset of magnonic bandstructure and its unique spatial distribution of magnetic excitations. The magnonic behaviour is visualized by the resonant interaction of these spin wave modes with elastics waves, which are simultaneously generated with, and phase-locked to, the magnonic profile. Calculation of the spin wave modal distribution in a laterally modulated magnetization landscape, using both the Plane Wave Method and micromagnetic simulations, provide a unified picture of the non-trivial precessional dynamics observed in our experiment.

Abstract: We performed simulations of coupled charge-spin-magnetization dynamics in magnetoelectric heterostructure which consists of two high-permittivity dielectrics separated by two conducting ferromagnetic layers. The layers are magnetized either parallel or antiparallel to each other. We show that it is possible to affect magnetization dynamics with an ac voltage applied to such heterostructure. The effect is driven by the field-like and anti-damping spin transfer torques.

Abstract: We present results of the theoretical investigation of the spin wave beam reflection off the ferromagnetic film’s edge and/or the gradually decreasing magnonic refractive index. In particular, we demonstrate the Goos-Hanchen and the mirage effects for spin waves. Furthermore, the scattering of the incident spin wave beam at the edge spin waves, which causes the excitation of secondary beams with the increased/decreased frequency, will be discussed, as well.

Abstract: The Hartman effect is the wave phenomenon observed for the wave package tunneling through the barrier where the evanescent solutions exist. This effect is manifested by the saturation of group delay of tunneling wave package with increasing width of the barrier. We showed the possibility of existence of the Hartman effect for the exchange spin waves. We took into account the general Barnaś-Mills boundary conditions in order to calculate the transmission of spin wave through the anisotropy barrier.

Addresses:
(1) Ulyanovsk State University, Ulyanovsk, Russia
(2) Donetsk Institute for Physics and Engineering of the National Academy of Sciences of Ukraine
(3) Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
(4) Faculty of Physics, V. N. Karazin Kharkiv National University, Kharkiv

Abstract: The lateral shift of reflected light beam, known as Goos-Haenchen effect, is theoretically studied for Brillouin light scattering by acoustic phonons and spin waves for Daemon-Eshbach geometry [1].
[1] Yuliya Dadoenkova, Nataliya Dadoenkova, Maciej Krawczyk and Igor Lyubchanskii, Goos-Hänchen effect for Brillouin light scattering by acoustic phonons, Optics Letters 43 (16), 3965 – 3968 (2018).

Abstract: Magnetic skyrmions are topologically protected nano-meter sized chiral spin textures with an out of plane magnetic domain at the center. Due to their various unique features such as stability given by their topology, they are considered as potential candidates for information carriers in next generation data storage devices, like racetrack memory. Therefore, it is crucial to be able to manipulate their current-induced motion in various directions. Magnetic antidot arrays can be used as a controller for skyrmion motion by using properly designed sequences of electrical current pulses, which marks a big leap toward skyrmion based devices, like logic gates, magnonics filters or demultiplexers.

Abstract: Magnetic skyrmion is a kind of topological soliton, a non-trivial inhomogeneous magnetization texture on the nanoscale. In this talk I focus on the skyrmion stability and spin excitations in ultrathin magnetic films and cylindrical magnetic dots. The skyrmions can be stabilized due to an interplay of the isotropic and Dzyaloshinskii-Moriya exchange interactions, out-of-plane magnetic anisotropy and magnetostatic interaction.

Abstract: The X-ray microscopy allows the application of powerful spectroscopic techniques in length scales far smaller than possible with optical microcopy. Near Edge X-ray Absorption Fine Structure (NEXAFS) gives the possibilities to the element and chemically sensitive imaging, while X-ray Circular Magnetic Dichroism (XMCD) allows direct, highly sensitive detection of sample magnetization. These contrast mechanisms at spatial resolutions of below 15 nm, and even better-using emergent techniques like ptychography, combined with the possibility of using the time structure of synchrotron light for pump- and- probe imaging with time resolutions of <50 ps make x-ray microscopy a powerful tool.
[1] W. Chao et al.: Nature 435 (2005) 1210.
[2] D. A. Shapiro et al.: Nature Photonics 8 (2014) 765.
[3] S. Woo et al.: Nature Materials 15 (2016) 501.
[4] K. Litzius et al.: Nature Physics 13 (2017) 170.
[5] S. Wintz et al.: Nature Nanotechnology 11 (2016) 948.

Abstract: Surface Acoustic Waves (SAWs) and Backward Volume Magnetostatic Spin Waves (BVMSWs) in bilayer substituted YIG (Yttrium Iron Garnet) samples. The bottom layer is characterised by in-plane magnetisation direction, while the top layer’s magnetisation direction is out-of-plane. The spectra were obtained by Brillouin Light Scattering (BLS) method for different magnetic configurations. The dispersion relations for aforementioned waves has been designated by analyzing the spectral data.
This work was supported by National Science Centre of Poland Grant No. UMO-2016/21/B/ST3/00452 and the EU’s Horizon 2020 Research and Innovation Program under Marie Sklodowska-Curie Grant Agreement No. 644348 (MagIC).

Abstract: The performance gain-oriented nanostructurization has opened a new pathway for tuning mechanical features of solid matter vital for application and maintained performance. Simultaneously, the mechanical evaluation has been pushed down to dimensions way below 1 µm. In this work, by means of micro-Brillouin light scattering we determine the mechanical properties, that is, Young modulus and residual stress, of polycrystalline few nanometers thick MoS2 membranes in a simple, contact-less, nondestructive manner. The results show huge elastic softening compared to bulk MoS₂, which is correlated with the sample morphology and the residual stress.

Abstract: Inelastic light scattering is a powerful method to study the dispersion relations of magnons and phonons. We determine the dispersion relation of thermal magnons and phonons which exist in the multilayered sample using Brillouin light scattering (BLS) spectroscopy in CoFeB/Au multilayer deposited on the silicon substrate with Ti and Au layers.In the backward scattering geometry, the dispersion relations of magnons and phonons are determined for different values of the magnetic field. The finite element method (FEM) is used for interpretation of the experimental results.
This work was supported by National Science Centre of Poland Grant No. UMO-2016/21/B/ST3/00452 and the EU’s Horizon 2020 Research and Innovation Program under Marie Sklodowska-Curie Grant Agreement No. 644348 (MagIC).

Abstract: Experimental and theoretical study of the phononic band gap in the hypersonic range for thermally activated Surface Acoustic Waves will be presented. Two dimensional phononic crystals have been studied by the Surface Brillouin Light Scattering. The experimental data will be compared with results of theoretical modeling by the Finite Element Method.

Abstract: Magnonic quasicrystals exceed the possibilities of spin waves (SW) manipulation offered by regular magnonic crystals, because of their more complex SW spectra with fractal characteristics. Here, we show the reprogrammability property of 1D Fibonacci magnonic quasicrystals, which allows controlling the SWs transmission. We demonstrate this property in the structures of different elements sizes and thus show the scalability of this system down to the nanometer scale.

Abstract: One of the greatest advantages of spin waves is high frequency associated with low energy loss, therefore spin waves are promising as prospective information carriers. However, the usability of the devices based on spin waves is dependent on the range of operating frequency. The customizable frequency range may be achieved by changes in structural parameters, hence we consider spin wave pinning as a relatively easy way to adjust the frequency. Numerical calculations were made for CoFeB stripes arranged in the horizontal plane. We checked how the change in the width, thickness, and distance between the stripes affects the FMR frequency.

Abstract: We have studied theoretically spin wave dynamics in planar magnonic quasicrystals and compared obtained results with the corresponding magnonic crystals. We have found that magnonic quasicrystals are characterized by complex spin wave spectra of a fractal nature and that spin waves of higher frequencies are localized in the bulk region of an intact system. Moreover, the lifetime of spin wave modes in magnonic crystals and magnonic quasicrystals will be presented.

Abstract: Fabrication and modeling of patterned thin films with perpendicular magnetic anisotropy rise great interest due to their wide applications in magnetic storage, sensors and magnonic crystals. A good representative of such systems are well-ordered arrays of magnetic antidots and dots based on Co/Pd multilayers, where magnetic reversal mechanisms strongly depend on the array geometry [1, 2]. We attempt to understand and reproduce the observed magnetic properties and domain structure appearing in the arrays by micromagnetic simulations performed using Mumax3 software [3]. In particular, changes in coercivity field, magnetic anisotropy constant and magnetic domain arrangement were studied and correlated with symmetry and size of nanostructures. The calculations show how edge effects, defects and inhomogeneity affect magnetization reversal and domain wall pinning mechanism, which helps to design similar patterned systems with the specific magnetic properties. Acknowledgments The numerical simulations were supported in part by the PL-Grid Infrastructure.
[1] M. Krupinski, D. Mitin, A. Zarzycki, A. Szkudlarek, M. Giersig, M. Albrecht and M. Marszałek, Magnetic transition from dot to antidot regime in large area Co/Pd nanopatterned arrays with perpendicular magnetization, Nanotechnology 2017, 28, 085302.
[2] C. Banerjee, Pawel Gruszecki, J. W. Kłos, O. Hellwig, M. Krawczyk, and A. Barman, Magnonic band structure in a Co/Pd stripe domain system investigated by Brillouin light scattering and micromagnetic simulations, Phys. Rev. B 96, 024421
[3]Vansteenkiste, A.; Leliaert, J.; Dvornik, M.; Helsen, M.; Garcia-Sanchez, F.; Van Waeyenberge, B., The Design and Verification of Mumax3. AIP Adv. 2014, 4, 107133.

Abstract: We investigate remagnetization in the two-dimensional array of permalloy nanobars with periodic and Fibonacci order. Hysteresis loops measured with magneto-optic Kerr effect microscopy shows particular behaviour of the structure in the magnetization reversal process. Monte Carlo simulations of macrospins in effective field and micromagnetic simulations as well as theoretical investigations of demagnetizing fields and dipolar interactions complemented experimental results explaining occurent phenomenons.

Abstract: We study switching mechanisms between ferromagnetic and antiferromagnetic (F – AF) configurations in systems of elliptically shaped flat nanoparticles (macrospins) under a variable applied magnetic field. Using a software based on the dynamical matrix method we compute frequencies and the corresponding spin profiles for the spin waves. Of special interest are those in the gigahertz frequency region. Limits of stability of configurations are marked by soft spin waves. We present various possibilities of enhancing recovery of the most stable AF configuration in a homogeneous external field.

Addresses:
(1) Institute of Nuclear Physics, Polish Academy of Sciences, Kraków
(2) Institute of Nuclear Physics, Cracow University of Technology, Kraków, Poland
(3) Department of Physics and Earth Sciences, CNISM Unit, University of Ferrara, Ferrara

Abstract: A transition between group-subgroup unrelated configurations is always discontinuous and often marked by a large hysteresis that impedes the switching of the configurations by varying a control parameter. This is e.g. characteristic of martensitic phase transitions. It will be shown that in some specific spin systems the hysteresis width may be reduced to zero in analogy to the second order phase transitions. Possible applications of such systems in the most efficiently switchable devices will be discussed.

Abstract: Photonics crystal slab (PC) consists of one, two, or three dimensions periodic array structures which are widely used for many applications in photonics such as guiding the light (waveguide), high-quality factor cavity resonator, photonic crystal fibers, and so on. In general, PCs are designed by removing the certain portion of the periodic array structures so-called defect region and this defect region is used to guide the light. We study a new hybrid PC slab which consists of dielectric rods coated with a thin layer of metal cap structures, and the defect region is created by just removing the thin layer of the metal cap. In this talk, I will present the various modes which exists in the defect region, and I will present the properties of different modes while propagating the light in different shapes of the waveguide.

Abstract: A monolayer graphene is a perfect material allowing for high frequency transport of electrons. Due to missing energy band gap its application in switching devices is not possible. The only way to open the band gap is symmetry breaking of a monolayer graphene.Topological insulators are famous of lack of scattering of electrons on structural defects. Topologically protected states can be observed in samples of thickness of 2 – 7 nm where contribution of bulk electrons bulk is limited. Fabrication of such thin layers requires advanced techniques like MBE. To reduce contribution of bulk electrons to surface conductivity one have to break symmetry of the topological insulator along zdirection. During this talk I will present results showing the effect of symmetry breaking in both materials due to surface plasmon generation.

Abstract: Angular- and wavelength-dependent magnetic second harmonic generation (mSHG) on periodic arrays of nickel nanodimers allowed us to identify a periodic structure acting as a meta-surface (diffraction forbidden) at the fundamental frequency and diffraction grating (diffraction allowed) at the double SHG frequency and observe the purely nonlinear Wood’s anomaly. Similar measurements on magneto-plasmonic multilayers in Kretschmann configuration are used to quantify the nonlinear phase-matching condition and magnetic control of surface plasmon polaritons generated at the SHG frequency.

Abstract: We discuss a specific Bethe Ansatz solution [1,2] of the eigenproblem of the Heisenberg Hamiltonian for a magnetic isotropic ring with N=7 nodes, at the centre k=0 of the Brillouin zone, within the three-magnon sector r=3, which implements an arithmetic qubit with the energy E=-5, and whose the basis states are rigged string configurations. We demonstrate that this qubit exhibits Galois symmetry, represented by the dihedral group D6 permuting six admissible state parameters of r=3 Bethe pseudoparticles.
[1] T. Lulek, M. Łabuz, J. Milewski, and R. Stagraczyński, Physica B550, 294 (2018)
[2] J. Milewski, B. Lulek, T. Lulek, and R. Stagraczyński, Physica B434, 14 (2014).

Addresses:
(1) Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
(2) Faculty of Physics, Adam Mickiewicz University, 61-614 Poznań, Poland
(3) School of Physics and Astronomy, University of Southampton, Southampton, United Kingdom
(4) Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Universita di Messina, Messina, Italy
(5) Physics Department, The University of Michigan, Ann Arbor, Michigan, USA

Abstract: We show how analogs of a large number of well-known nonlinear-optics phenomena can be realized with one or more two-level atoms coupled to one or more resonator modes in the ultrastrong-coupling regime. Through higher-order processes, where virtual photons are created and annihilated, an effective deterministic coupling between two states of such a system can be created. In this way, analogs of three-wave mixing, four-wave mixing, higher-harmonic and -subharmonic generation (i.e., up- and down-conversion), multiphoton absorption, parametric amplification, Raman and hyper-Raman scattering, the Kerr effect, and other nonlinear processes can be realized. In contrast to most conventional implementations of nonlinear optics, these analogs can reach unit efficiency, only use a minimal number of photons (they do not require any strong external drive), and do not require more than two atomic levels [1,2,3].
[1] A. F. Kockum, A. Miranowicz, V. Macri, S. Savasta, F. Nori, Phys. Rev. A 95, 063849 (2017), e-print arXiv:1701.05038 .
[2] R. Stassi, V. Macri, A. F. Kockum, O. Di Stefano, A. Miranowicz, S. Savasta, and F. Nori, Phys. Rev. A 96, 023818 (2017), e-print arXiv:1702.00660 
[3] A. F. Kockum, A. Miranowicz, S. De Liberato, S. Savasta, and F. Nori, in press in Nature Reviews Physics, e-print arXiv:1807.11636 .

Abstract: The formulae for linear electric polarization induced by harmonic electric field in liquids composed of rigid noninteracting dipolar and asymmetric-top molecules in spherical solvents are derived. The model of noninertial, anomalous rotational Brownian motion is applied. The fractional rotational diffusion equations are solved and time evolution of the electric polarizability is investigated for the case when a dc-electric field is turned off and for the stationary state case when only an ac-field is present. Numerical analysis of the dispersion and absorption parts of electric polarizability is performed as well as the influence of molecular parameters on so-called Cole-Cole plots is investigated.

Abstract: [PDF]  Modern medicine widely uses exogenous collagen as good material for tissue regeneration, also as natural substrate for cell attachment and proliferation, used to create dressings and to support the treatment of burn wounds or diabetic wounds, or finally as a source of amino acids in the diet complementary to the body’s needs [1,2]. Collagen is a safe material that has a high biocompatibility and biodegradability and good cell adhesion [3]. Due to the possibility of transferring Creutzfeld-Jacob disease(Bovine Spongiform Encephalopathy) from animals to the human body, the interest in collagen from fish increased. The collagen we examined comes from the skin of silver carp fish (Hypophtalmichthys molitrix), and was obtained by method of hydration in an aqueous lactic acid solution [4]. The topography of the test sample was made with The Dimension® Icon™ Scanning Probe Microscope (SPM), showing its fibrillar structure, with dimensions equivalent to those shown in the literature [5]. Raman spectroscopy was used to study fish collagen using a Renishaw Ramascope 1000 spectrometer. The source of the excitations was a helium-neon laser with a wavelength of 633 nm. Analysis of Raman spectra allowed to determine the content of amino acids in collagen, including glycine, proline and hydroxyproline. It also showed the native nature of the material at 20⁰C. The durability of the secondary structure of this material heated to about 90⁰C and cooled was also proved. Raman spectroscopy has been presented as an effective method for testing biopolymers [6].
[1] Sanz M and all, Clinical Evaluation of a New collage matrix (mucograpf prototype) to enhance the wight of keratinized tissue In patients with fixed prosthetic restorations: a randomized prospective clinical trial. J. Clin Periodontol. 2009; 36 (10), 868-876.
[2] Ghanaati S et al, Evaluation of the tissue reaction to a new bilayered collagen matrix in vivo and its translation to the clinic. Biomed Mater. 2011(1); 015010.
[3] Sionkowska A. Current reaserch on the blends of natural and synthetic polymers as new biomaterial: review. Progress in Polimer science, 2011; 36: 1254-1276.
[4] Przybylski J.E., Patent US 7285638, B2 (2007).
[5] Buehler M.J., Nature designs tough collagen: Explaining the nanostructure of collagen fibrils, Proceedings of the National Academy of Sciences Aug 2006, 103 (33) 12285-12290.
[6] Paprzycka M, Scheibe B, Jurga S, Fish collage – molecular structure after thermal treatment, Fibres & Textile In Eastern Europe, 132, 2018.

Addresses:
¹Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Science of the Czech Republic, Olomouc, Czech Republic
² Quantum Optics and Engineering Division, Institute of Physics, University of Zielona Góra, Zielona Góra, Poland

Abstract: Long-time photoelectron ionization spectra of a system with an auto-ionizing level interacting with a neighbor two-level atom are discussed. These spectra are typically composed of several peaks. Conditions for the occurrence of Fano and Fano-like zeros are revealed. Photoelectron ionization spectra conditioned by the measurement on the two-level atom show oscillations at the Rabi frequency of the neighbor two-level atom. The presence of spectral dynamical zeros in the conditioned spectra is predicted. Also entanglement between an ionized electron and that bound on the two-level system is analyzed using negativity. Two-dimensional spectral density of negativity is defined to identify spectrally local entanglement between two electrons. It reveals that entanglement is ‘concentrated’ around spectral peaks.

Abstract: In my talk I would like to remind some historical facts from the biography of Professor Stanisław Kielich related to the beginning and progress of nonlinear optics in Poznań.

Abstract: Investigations of mesoscopic twin beams containing typically several photon pairs using an iCCD camera with single-photon resolution will be discussed. Operation of the camera as a photon-number-resolving detector endowed with spatial resolution will be analyzed. Different types of reconstructions of the joint signal-idler photon-number distributions of twin beams will be discussed including the method of maximal likelihood and that assuming a multimode Gaussian form of in general noisy twin beams. Also the use of spatial correlations inside twin beams for reducing the noise in the experimental data and subsequent less-noisier reconstruction of the joint photon-number distribution will be mentioned. Reconstruction of the joint signal-idler quasi-distributions of integrated intensities will be discussed. Different types of nonclassicality (entanglement) criteria written in terms of integrated-intensity moments as well as using directly the elements of photon-number distributions will be introduced. The method of absolute detector calibration principally based on pairing of photons in twin beams will be presented. Postselection by photon-number-resolving detection as a tool for generating (higher-order) sub-Poissonian states of light will be discussed based on the experimental results.

Abstract: Single photon generation can be obtained either in optical systems with strong single-photon nonlinearities (conventional photon blockade) or in the systems with extremely weak optical nonlinearities (unconventional photon blockade). Such photon blockades are associated with sub-Poissonian statistics and strong antibunching. We will discuss possibility of observing single, multiphoton and non-standard blockades with squeezed states. An example of dissipative squeezing interactions will be given.

Abstract: Many applications in quantum technologies, such as quantum cryptography or optical quantum information processing, require light sources with a precise number of photons. Photon (phonon) blockade is the quantum phenomenon that occurs in a driven nonlinear system, in which a single photon (phonon) in the system prohibits the generation or entry of other photons (phonons) to the system. These effects are described by the sub-Poissonian excitation-number statistics. Here we describe cases such that a combined photon-phonon mode exhibits sub-Poissonian statistics, while each mode, if analyzed separately, exhibits super-Poissonian statistics.

Abstract: We present a method that allows one to completely reveal nonclassicality of Gaussian states of light, initially generated in optical spontaneous parametric processes, by means of an appropriately induced stimulated emission. Namely, we exploit the fact that stimulating fields in stimulated emission processes for Gaussian states play the role of displacing coherent fields, which, therefore, by no means affect nonclassicality of initially generated Gaussian states. Then, by utilizing a certain nonclassicality criterion, which is expressed in terms of integrated intensity moments of optical fields up to the second order, we show that one can truly certify the presence of quantum correlations of such Gaussian states by varying the complex amplitude of stimulating coherent fields.

Abstract: The quantum properties of polarisation-correlated photon pairs like, e.g., quantum entanglement, purity etc. make them a powerful resource in quantum communication, including quantum key distribution protocols. These properties and their quantifiers, which can be defined in terms of distances in Hilbert space, are usually measured indirectly by first performing complete quantum state tomography and then calculating their value from the reconstructed density matrices. In many cases this procedure requires performing more measurements than necessary to characterise the investigated quantum property and it tells little about the nature of the characterised property. I will explain how to directly measure the distance between points in Hilbert space using single photons, the maximal level of Bell inequality violation, a universal entanglement witness and the negativity of an arbitrary two-photon polarisation state by only two-photon interference of photons assorted from a few (at most four) copies of the investigated state. I will discuss the experimental challenges and limitations of this approach as well as the possible solutions within the framework of linear optics.
[1] Bartkiewicz, K., Horst, B., Miranowicz, A., “Entanglement estimation from Bell inequality violation,” Phys. Rev. A 88, 052105 (2013).
[2] Bartkiewicz, K., Lemr, K., Černoch, A., Miranowicz, A, “Bell nonlocality and fully entangled fraction measured in an entanglement-swapping device without quantum state tomography,” Phys. Rev. A 95, 030102R (2017).
[3] Bartkiewicz, K., Horodecki, P., Lemr, K., Miranowicz, A., Życzkowski, K., “Method for universal detection of two-photon polarization entanglement,” Phys. Rev. A 91, 032315 (2015).
[4] Bartkiewicz, K., Beran, J., Lemr, K., Norek, M., Miranowicz, A., “Quantifying entanglement of a two-qubit system via measurable and invariant moments of its partially transposed density matrix,” Phys. Rev. A 91, 022323 (2015).
[5] Bartkiewicz, K., Chimczak, G., Lemr, K., “Direct method for measuring and witnessing quantum entanglement of arbitrary two-qubit states through Hong-Ou-Mandel interference, ” Phys. Rev. A 95, 022331 (2017).
[6] Bartkiewicz, K., Chimczak., “Two methods for measuring Bell nonlocality via local unitary invariants of two-qubit systems in Hong-Ou-Mandel interferometers,” Phys. Rev. A 97, 012107 (2018).
[7] Bartkiewicz, K., Lemr, K., Černoch, A., Soubusta, J., “Measuring nonclassical correlations of two-photon states,” Phys. Rev. A 87, 062102 (2013).
[8] Trávníček, V., Bartkiewicz, K., Černoch, A., Lemr. K., “Experimental measurement of a nonlinear entanglement witness by hyperentangling two-qubit states,” Phys. Rev. A 98, 032307 (2018).

Abstract: Beam-splitter is a very common component of setups for quantum information experiments. The quality of measurement results strongly depends on its parameters especially on splitting ratio. In this talk some tricks how to fine tune the splitting ratio will be shown.

Addresses:
(1) Institute of Physics, University of Zielona Góra, Poland
(2) Joint Laboratory of Optics of Palacky University and Institute of Physics of Czech Academy of Sciences, 771 46 Olomouc, Czech Republic

Abstract: [PDF]  We are used to the fact that all bipartite pure entangled quantum states violate a Bell inequality. This means that measurement results on this quantum system manifest nonlocal correlations. So far the relationship between entanglement and nonlocality is still a subject of an intense study. Recently a new measure of nonlocality was proposed [1]. It is defined as the probability, that the pure state will display nonlocal correlation when subjected to random measurements. When scanning over all possible projection measurements, we can define a nonlocal volume, which corresponds to the subspace in which the projection measurements prove nonlocality of the input state. We decided to test these relations for three-qubit states, generalized Greenberger-Horne-Zeilinger (gGHZ) states [2]. It was recently shown that the nonlocal volume has very convenient properties. For example, for pure states this measure is monotonic with entanglement described by the gGHZ angle. The more the state is entangled, the larger is the probability to violate Bell inequalities selecting random measurements. For this purpose we first had to build an efficient experimental setup, that is capable to generate the gGHZ states. states and to carry out the optimal measurements very fast. Secondly, we have experimentally verified numerical simulations of optimal measurements proposed to detect the greatest violation of several Bell-type inequalities for three-partite states [3, 4]. Finally, we have started detailed experimental mapping of the projection measurement space to get the nonlocal volume of the tested states. We hope that this both theoretical end experimental research can help to get better insight into the abstract quantities characterizing quantum states and also to the mutual relationship between them [5, 6].
[1] V. Lipińska, F. J. Curchod, A. Mattar, and A. Acin, New J. Phys. 20, 063043 (2018).
[2] D. M. Greenberger, M. A. Horne, A. Shimony, and A. Zeilinger, Am. J. Phys. 58, 1131 (1990).
[3] G. Svetlichny, Phys. Rev. D 35, 3066 (1987).
[4] J.-D. Bancal, J. Barrett, N. Gisin, and S. Pironio, Phys. Rev. A 88, 014102 (2013).
[5] I. Arkhipov, A. Barasiński, and J. Svozilik, Sc. Rep. 8, 16955 (2018).
[6] A. Barasiński, Sc. Rep. 8, 12305 (2018).

Abstract: We present engineering a fully controllable effective coupling between two quantized cavity modes via an ensemble of four-level atoms in the diamond configuration. This controllable effective coupling makes it possible to transfer coherent superpositions of cavity-mode number states from one mode to the other on demand. We also show that despite the fact that the system is complex, it is possible to describe its evolution using a simple effective Hamiltonian.

Addresses:
(1) Quantum Optics and Engineering Division, Institute of Physics, University of Zielona Góra, Z. Szafrana 4a, 65-516 Zielona Góra, Poland
(2)RCPTM, Joint Laboratory of Optics of Palacky University and Institute of Physics of Academy of Sciences of the Czech Republic, 17. Listopadu 12, 772 07 Olomouc, Czech Republic

Abstract: Quantum entanglement plays an important role in quantum theory as one of the most unintuitive physical phenomenons. Because of many possible applications, characterization of quantum states is an important task. While the calculation of entanglement measures for pure two-qudit states is not challenging, it becomes significantly much more complicated in case of mixed two-qudit states. The basic approach to this problem is restriction the specific subgroup of states which obey specific symmetrical conditions. Here we discus a recently introduced highly symmetric qudit states family with incomplete permutation symmetry [1, 2] This family consists of both pure and mixed states and can be described by five real parameters. For those states we perform extensive analysis of various conditions of separability and entanglement classification. Furthermore our results can be used for any arbitrary quantum state by application of twirling operator.
[1] A. Barasiński and M. Nowotarski, Phys. Rev. A 94, 062319 (2016)
[2] A. Barasiński and M. Nowotarski, Phys. Rev. A 95, 042333 (2017)

Addresses:
(1) Quantum Optics and Engineering Division, Institute of Physics, University of Zielona Góra, Zielona Góra, Poland
(2) Institute of Physics, Częstochowa University of Technology, Częstochowa, Poland

Abstract: We have analyzed the dynamics of the positively charged ion of a diatomic molecule, in which the atomic cores are under the influence of an external force of harmonic-type which is explicitly dependent on the amplitude and frequency. The ground state of the ion has been determined using the variational method. The influence of charge core asymmetry on such state energy and the filling of ion nodes has been calculated. We have also verified how the charge asymmetry of the cores affects the value of the Lyapunov exponent.

Addresses:
(1) Quantum Optics and Engineering Division, Faculty of Physics and Astronomy, University of Zielona Góra, Zielona Góra, Poland
(2) Joint Laboratory of Optics of Palacký University and Institute of Physics of CAS, Faculty of Science, Palacký University, Olomouc, Czech Republic
(3) Institute of Physics, Częstochowa University of Technology, Częstochowa, Poland

Abstract: Analysis of quantum dynamics of the systems which classical counterparts exhibit chaotic behavior seems to be one of the most intriguing topics related to the quantum dynamics’ research. In particular, finding the methods allowing detection of the appearance of the quantum chaos is especially intriguing. We consider here the application of the normally ordered variances of the quadratures operators as a witness of quantum-chaotic evolution. We discuss them in a context of the anharmonic Kerr-like oscillator excited by a series of ultra-short coherent pulses.

Abstract: In the quantum world, correlations can take the form of entanglement which is known to be monogamous. Following Phys. Rev. Lett. 121, 090403 (2018), we will argue that another type of correlation, indistinguishability, is also restricted by some form of monogamy. Namely, if particles A and B simulate bosons, then A and C cannot perfectly imitate fermions. The main point of this talk consists in demonstrating to what extent it is possible.

Abstract: It was recently suggested that two entangled fermions can behave like a single boson and that the bosonic quality is proportional to the degree of entanglement between the two particles. The relation between bosonic quality and entanglement is quite natural if one takes into account the fact that entanglement appears in bound states of interacting systems. However, entanglement can still be present in spatially separated subsystems that do not interact anymore. These systems are often a subject of studies on quantum nonlocality and foundations of quantum physics. In the first half of this talk, I will discuss whether an entangled spatially separated fermionic pair can exhibit bosonic properties. I will consider certain conditions under which the answer to this question can be positive. In addition, I will present a nonlocal bunching scenario in which two of such pairs form an analogue of a two-partite bosonic Fock state. In the second half of this talk, I will present our new findings regarding the behaviour of a system of N identical pairs of fermions within the Hubbard model. I will show that with certain types of interaction, the ground state of this system will be reduced to an N-partite bosonic Fock state.

Abstract: There is an intriguing idea that quantum theory would be recovered if standard probabilities were replaced by negative probabilities and some events were deemed unobservable. However, such approach would be able to recover only one half of quantum theory – state description and measurement. The other half of the theory describes how states change in time. In this presentation I will discuss which evolutions of negative probability distributions are allowed. It is known that the evolution of standard probability distributions is determined by stochastic matrices, which generate either simple reversible permutations, or fundamentally irreversible dynamics. On the other hand, the evolution of negative probability distributions can be described by pseudo-stochastic matrices, i.e., matrices whose entries are given by negative probabilities. These matrices give rise to a much richer dynamics in which there are nontrivial reversible transformations.

Abstract: One of the most surprising predictions of general relativity is possibility of time travel into one’s past. These so called closed timelike curves lead to the grandfather paradox. However Deutsch and also Bennett and Schumacher proposed quantum models which avoid this paradox. In this talk we show what are implications of these models to the Second Law of Thermodynamics.

Abstract: We demonstrate that non–linear entanglement witnesses can be made particularly useful for en- tanglement detection in hyper–entangled or multilevel states. We test this idea experimentally on the platform of linear optics using a hyper–entangled state of two photons. Instead of several simultaneous copies of two-photon entangled states, one can directly measure the witness on single copy of a hyper–entangled state. Our results indicate that hyper–entanglement can be used for quick entanglement detection and it provides a practical testbed for experiments with non–linear entanglement witnesses.

Addresses:
(1) RCPTM, Joint Laboratory of Optics of Palacký University and Institute of Physics of Academy of Sciences of the Czech Republic, Olomouc, Czech Republic
(2) Faculty of Physics, Adam Mickiewicz University, Poznań, Poland
(3) Institute of Physics of Academy of Sciences of the Czech Republic, Joint Laboratory of Optics of PU and IP AS CR, Olomouc, Czech Republic
(*) Presently on leave at Faculty of Physics, Adam Mickiewicz University, Poznań, Poland

Abstract: The concept of quantum money has been originally suggested by S. Wiesner in the 1970s. Its main advantage is that every attempt to copy quantum banknotes leaves the quantum states changed providing a mark on money counterfeits. According to the no-cloning theorem the quantum states cannot be in general perfectly cloned (copied). However, an imperfect cloning is still possible. We present a version of an eavesdropping attack on the protocol proposed by Bozzio et al. (2018). The aim of our research is to demonstrate that cloning implemented even rarely enough that it is indistinguishable from noise is fully sufficient to acquire useful information to counterfeit quantum banknotes. We exploit the fact that completely random encoding of quantum banknotes is computationally impractical and that the bank needs to select a non-random but secret encoding algorithm. Data analysis or machine learning allow the attacker to discover bank’s secret and thus predict future banknotes merely on the basis of partial information gained by cloning of previous banknotes.

Abstract: The talk discusses the possibility to use collective entanglement witnesses, namely the collectibility, in quantum relay diagnostics. Theoretical concept as well as an experimental implementation shall be presented. The talk promotes benefits of this idea by comparing its experimental requirements with previously used methods.

Abstract: We discuss a system of three qubits and concentrate on the quantum steering effect appearing in such a system. In particular, we discuss the relations of the steering with the other form of quantum correlations, the quantum entanglement [1,2]. Additionally, we present how the interesting us effects can appear in the three-mode triangle Bose–Hubbard system [3].
[1] J. K. Kalaga, W. Leoński, Quant. Inf. Process. (2017) 16:175
[2] J. K. Kalaga, W. Leoński, J. Perina Jr., Phys. Rev. A (2018) 97:042110
[3] J. K. Kalaga, W. Leoński, R. Szczęśniak Quant. Inf. Process. (2017) 16:265

Abstract: Quantum correlations in multi-qubit systems are subject of intensive studies because of their crucial role in quantum information processing. Probably the most popular measure of correlations is entanglement, but there are other measures that have been introduced and studied, such as quantum discord, geometric quantum discord, measurement induced disturbance and others. The simplest bipartite system in which the correlations can be studied is a system of two qubits, or two two-level atoms. In case of two-level atoms interacting with the reservoir of electromagnetic field modes in the vacuum, the evolution of the system can be described by the well known Lehmberg-Agarwal master equations. The collective evolution of the two-atom system depends on two collective parameters: collective damping 12 and dipole-dipole interaction γ₁₂, which both depend on the interatomic distance. Such a system is a good testing ground for studying evolution of quantum correlations. We study a more complex system of three-atoms embedded in a common vacuum. Such a system is more difficult to describe because, for mixed states, we deal with 8×8 matrix which leads to 63 equations, and, what is even worse, there are no formulas to calculate concurrence, even if we know all the matrix elements. Fortunately, it is possible to calculate negativity, which is another measure of entanglement. Concurrence and negativity give the same values for pure states, but are different for mixed states. So, we use negativity as a measure of entanglement in a three-atom system. Master equation for the density matrix is solved, and we find evolution of the negativity in a three-atom system. The evolution depends on the collective parameters γ_ij and Ω_ij. We test, in particular, the so called monogamy relations for negativity, for chosen initial states of the system. It is shown that for some states monogamy relations are violated.

Abstract: During the seminar, I will give a short introduction to quantum metrology, which, generally speaking, aims at enhancing the sensitivity of measurement beyond the classical limit of precision. One of the most exciting aspects of quantum metrology is the possibility to harness entangled states of many-body quantum systems. On the example of a two-mode Bose-Einstein condensate, I will show how to generate such states and use them subsequently in the process of estimating an unknown parameter. I will explain why entangled states can enhance the sensitivity of measurement and why the use of them is currently restricted to proof-of-principle experiments. To overcome this limitation, I will show an alternative way (without entanglement) of enhancing the sensitivity by exploiting features of an exotic state of matter known as supersolid. Finally, I will show how one of the central theoretical tools in quantum metrology, quantum Fisher information, can be used to study quantum chaos.

Streszczenie: Współczesna krystalografia stanowi podstawowe narzędzie badania struktury kryształów molekularnych. Statyczny obraz struktury średniej kryształu, definiowanej przez uporządkowanie dalekiego zasięgu, ma bez wątpienia znaczenie fundamentalne, jest on jednak obrazem niepełnym. Spojrzenie na kryształy molekularne z alternatywnej perspektywy, tj. lokalnego otoczenia molekuły, pozwala uzupełnić naszą wiedzę na temat struktury i dynamiki sieci krystalicznej oraz rządzących nią oddziaływań. W tym kontekście, metody spektroskopii ciała stałego stanowią nieodzowne narzędzie badawcze, gdzie spektroskopia jądrowego rezonansu magnetycznego, NMR, może być uznana za metodę wiodąca prym. Rozwój spektroskopii NMR doprowadził do zaproponowania koncepcji krystalografii NMR, uznanej powszechnie jako pełnowartościową metodę badań strukturalnych. W referacie przedstawiona zostanie analiza możliwości wykorzystania wspieranych-obliczeniowo metod komplementarnych do NMR w badaniach kryształów molekularnych wykazujących różny stopień nieporządku. Bazując głównie na metodach spektroskopii neutronowej, przedstawione zostaną przykłady badań układów o znaczeniu zarówno poznawczym (kryształy molekularne z wiązaniem wodorowym) jak i aplikacyjnym (substancje farmaceutyczne oraz perowskitowy materiał fotowoltaiczny).

Abstract: The introduction of artificial magnetic structures into magnetic materials can induce novel electromagnetic and spin-wave behavior. Nano- and submicrometer-scale artificial magnetic lattices (AMLs) can control optical (electromagnetic) waves in magnetophotonic crystals [1], volumetric magnetic holograms [2], and labyrinthian magnetic domain structures [3], and can affect spin waves in magnonic crystals [4]. In this talk, the fundamental properties of such AMLs, mainly in magnetic garnet films and alloy thin films, are discussed, followed by demonstrations of their applications in optical and spin-wave micro-devices driven by magnetic phase interference: volumetric magneto-optic (MO) hologram memories [2] and three-dimensional MO holographic displays [5] with magnetophotonic crystals; high-speed MO Q-switch micro-chip lasers with iron-garnet films with labyrinthian magnetic domain structures [3]; and highly sensitive magnetic sensors and spin-wave logic circuits with magnonic crystals [6]. Prospective future spin-wave devices with AMLs will be discussed in the context of the new paradigm of magnonics (electron non-transport electronics), where spin waves play an important role as the information carrier.

[1] T. Goto et al., “Magnetophotonic crystal comprising electro-optical layer for controlling helicity of light,” J. Appl. Phys., vol. 111, 07A913, 2012.
[2] Y. Nakamura et al., “Error-free reconstruction of magnetic hologram via improvement of recording conditions in collinear optical system,” Optics Exp., vol. 25, pp. 15349-15357, 2017.
[3] R. Morimoto et al., “Magnetic domains driving a Q-switched laser,” Sci. Rep., vol. 6, 38679, 2016.
[4] N. Kanazawa et al., “Metal thickness dependence on spin wave propagation in magnonic crystal using yttrium iron garnet,” J. Appl. Phys., vol. 117, 17E510, 2015.
[5] K. Nakamura et al., “Improvement of diffraction efficiency of three-dimensional magneto-optic spatial light modulator with magnetophotonic crystal,” Appl. Phys. Lett., vol. 108, 022404, 2016.

Biography: Mitsuteru Inoue received the B.S. degree in information engineering and the M.S. and DrEng. degrees in electrical and electronic engineering in 1981, 1983, and 1989 from Toyohashi University of Technology (TUT), Japan. He was an associate professor at TUT from 1993 to 1996, and with the Research Institute of Electrical Communication, Tohoku University, from 1997 to 1999. From 2001 to 2013 he served as professor in the Department of Electrical and Electronic Engineering, TUT. Since 2014 he is jointly serving as professor of the Graduate School of TUT and as an executive trustee and vice president of TUT. He was a visiting professor at Stanford University in 2003 and at Moscow State University in 2004.
His research interests include spin-coupled wave propagation phenomena in amorphous alloy and magnetic garnet thin films, including phase modulation of magneto-surface-acoustic-waves, control and phase modulation of optical waves, and control of high-frequency magnetostatic and spin waves, together with their applications in magneto-optical (MO) spatial light modulators, three-dimensional MO displays, non-destructive MO imaging, magnetic hologram recording, and spin-wave logic circuits.
Prof. Inoue has served as the director of Magnetics Society of Japan from 2013 to 2015 and as the general chair of the Magnetics and Optics Research International Symposium (MORIS, 2015 and 2018). He is currently the chair of the 147th Committee on Amorphous and Nano-Crystalline Materials of the University-Industry Cooperative Research Committees, Japan Society for the Promotion of Science (JSPS). [copied from ieeemagnetics.org] 

Streszczenie: Opisywane osiągnięcie naukowe dotyczy badań nad transportem i lokalizacją nośników ładunku i spinu w układach, których podstawową jednostką strukturalną jest płaszczyzna grafenowa. Badano dwie klasy materiałów: tlenki grafenu (o różnej zawartości tlenu w strukturze) oraz aktywowane włókna węglowe (o różnej porowatości). W prezentowanych badaniach użyte zostały trzy techniki badawcze: elektronowy rezonans paramagnetyczny, spektroskopia impedancyjna oraz stałoprądowy pomiar oporu elektrycznego, wsparte obrazowaniem mikroskopii elektronowej i analizą struktury chemicznej za pomocą spektroskopii fotoelektronów. Pomiary przeprowadzano w szerokim zakresie temperatur i w ściśle kontrolowanej atmosferze. Umożliwiło to zaobserwowanie zmian zachodzących w zachowaniu nośników ładunku w układach grafenowych w zależności od parametrów strukturalnych i fizykochemicznych oraz pod wpływem adsorpcji różnego rodzaju molekuł i zewnętrznego pola elektrycznego. Przedstawione wyniki pozwalają na wskazanie możliwości kontroli zachowania nośników ładunku w badanych materiałach, pod kątem zwiększenia ich przydatności w różnych zastosowaniach.

Abstract: Nonclassicality of light plays a crucial role in the field of quantum optics. The discovery of the nonclassical properties of light has led to the establishment of new branches of quantum physics, e.g., quantum information theory. One of the most known form of the nonclassicality of light is the entanglement, where different modes of quantum fields exhibit quantum correlations which have no analogue in the classical optics. Though a lot of progress has been made in the theory of the nonclassicality of the Gaussian states, still, the problem, how one can directly certify the nonclassicality of the Gaussian states in the experiment with the least available sources, has not been solved yet. During the seminar, I will present a new experimental method for complete identification of nonclassicality of Gaussian states of light in the whole phase space. The proposed method relies on nonclassicality witnesses written in terms of measured integrated intensity moments up to the second order, provided that appropriate local coherent displacements are applied to the state under consideration.

Streszczenie: Impulsowa spektroskopia laserowa pracująca w zakresie femtosekund, pikosekund i nanosekund staje się ważnym i coraz bardziej popularnym narzędziem badań podstawowych, umożliwiającym obserwacje najszybszych procesów zachodzących w przyrodzie. Za pomocą takiej spektroskopii możemy także poznać mechanizmy i dynamikę procesów transportu ładunków w fotoogniwach. Czy jednak badania z użyciem femtosekundowych impulsów laserowych mogą dzięki temu zostać użyte do bardziej praktycznych celów i pomóc w uzyskiwaniu lepszej sprawności ogniw słonecznych? Od kilku lat rozwijamy w naszej grupie badawczej czasowo-rozdzielcze absorpcyjne i emisyjne techniki laserowe stosowane do pomiarów fotoogniw barwnikowych (dye-sensitized solar cells) oraz fotoogniw perowskitowych. Specjalizujemy się w badaniu gotowych ogniw, które konstruujemy i dla których wykonujemy podstawowe pomiary fotowoltaiczne. Takie funkcjonale próbki są przedmiotem spektroskopowych badań laserowych, których głównym celem jest zaobserwowanie korelacji między zmierzonymi parametrami ogniw słonecznych a wynikami badań w krótkich czasach.

Abstract: Quantum information processing is an interdisciplinary field of research where physics meets information science and engineering. Its potential applications range from securing communications to solving computational tasks that have been infeasible on computers that relied on classical physics. These applications exploit the quantum features of a given quantum state through specifically designed hardware, e.g., quantum entanglement, fidelity, and temporal steering. Full quantum tomography is frequently conducted to characterise some of these features, which becomes prohibitively time consuming, especially in large systems. In this talk, I discuss alternatives to characterising quantum systems based on sequential and interferometric methods as well as experimental challenges related to their implementation.

Abstract: The talk will present the current state of the multiphoton quantum laboratory in Olomouc. I shall summarize recent experiments with three and four photons as quantum information carriers. Specifically, I will discuss our experiments on collective entanglement witnesses, quantum router and controlled quantum teleportation.

Abstract: This talk will give a general overview of the techniques involved in using two-dimensional electronic spectroscopy (2D-ES) and illustrate how 2D-ES can be used to study energy and charge transfer processes in materials of interest for next generation photovoltaics. The first part of this talk will focus on understanding the photophysics of carbon nanotube thin films and devices. Using our two-dimensional white-light (2D-WL) spectrometer we are able to explore exciton diffusion and hopping dynamics in order to better inform carbon nanotube device design. In the second part of this talk I will discuss our newer, faster version of 2D-WL spectroscopy using a pulse shaper and present an initial report on perovskite photophysics.

Abstract: The research field called Magnonics emerged with the paradigm of harnessing spin-waves (SWs) as the elemental carrier of information. With up to terahertz (THz) oscillation frequencies with nanometric wavelengths and over macroscopic propagation distances without electron charges being displaced, harnessing magnons paves the way toward applications with minimum joule heating effect, therefore with unprecedentedly low power consumption (energy- friendly environmental devices), reconfigurable functionality, faster operation and further miniaturization. The wavelike properties of SWs as phase and amplitude provides additional degrees of freedom in data processing and sensing, which lead for instance, to novel prototype building blocks of SW-based logic [1] and smart device for very efficient SW propagation channels [2]. The kernel of such applications generally consists of the so-called magnonic waveguides (MGs) and magnonic crystals (MCs), which are meta-materials characterized by their unprecedented on-demand reprogrammable functionality. Whether MGs or MCs, three aspects are generally assessed at the moment of studying SWs properties for fundamental physics and magnonic applications: (i) High efficiency in transmitting SWs power along magnetic tracks with minimum energy consumption, sub-micrometer wave length encoding (< 1 µm), large group velocity limits ( > 1000 m/s), large decay length ( > 6 µm) and small frequency linewidth ( < 100 MHz); (ii) large and tunable nonreciprocities in the dispersion relation, amplitude, power absorption, frequency linewidth and decay length of SWs, at sub-micrometer wavelengths, above GHz frequency range, and minimized energy expenditure. This feature is particularly advantageous in analog and digital operation based in SW logic devices, since non-reciprocity provides the condition for the unidirectional propagation of SW packages (avoiding the formation of standing SWs), which is strategic for enhancing the input/output information transfer encoded in the phase, frequency and amplitude of SWs; and (iii) efficient interface for input/output signals conversion between magnons and other types of information carries at high resolution of SW phase and frequency, and over a broad range of frequency coverage. Accordingly, it can be suggested that the ideal magnonic layout is that one which allows the versatility of enclosing the aforementioned three aspects in one single device; hence the potential of SWs as information carriers can be fully exploited. According to literature, these three aspects have been mainly studied in planar two-dimensional (2D) thin films, nevertheless, there is not yet a clear example wherein all of them can be achieved in only one single magnonic layout at once. We think that a promising route would consist in curving the 2D template into a curvilinear 3D-dimesional geometry, which simultaneously bring novelty to Magnonics because the intrinsic curvature-induced magneto-chiral effects in SWs.[3-5] This talk will be addressed in this direction.
[1] Wang et al., Sci. Adv. 4, e1701517 (2018)
[2] Wagner et al., Nat. Nanotech. (2016)
[3] Otálora et al., Phys. Rev. Lett. 117, 227203 (2016)
[4] Otálora et al., Phys. Rev. B. 95, 184415 (2017)
[5] Otálora et al., Phys. Rev. B. 98, 014403 (2018)

Abstract: We report on a new class of dimension witnesses, based on quantum random access codes, which are a function of the recorded statistics and that have different bounds for all possible decompositions of a high-dimensional physical system. Thus, it certifies the dimension of the system and has the new distinct feature of identifying whether the high-dimensional system is decomposable in terms of lower dimensional subsystems. To demonstrate the practicability of this technique, we used it to experimentally certify the generation of an irreducible 1024-dimensional photonic quantum state. Therefore, certifying that the state is not multipartite or encoded using noncoupled different degrees of freedom of a single photon. Our protocol should find applications in a broad class of modern quantum information experiments addressing the generation of high-dimensional quantum systems, where quantum tomography may become intractable [1].

[1] Edgar A. Aguilar, Máté Farkas, Daniel Martínez, Matías Alvarado, Jaime Carine, Guilherme B. Xavier, Johanna F. Barra, Gustavo Canas, Marcin Pawłowski, and Gustavo Lima, Phys. Rev. Lett. 120, 230503 (2018).

Streszczenie: Synergia (z gr. “συν” oznaczające “razem”, oraz “ϵργια” – dzieło, działanie) w kontekście badań naukowych oznacza podejście całościowe – kompleksowe. Od początku kariery naukowej zdecydowałam się na interdyscyplinarny charakter swoich badań i podążałam w tym kierunku konsekwentnie, pomimo wielu przeciwności. Obecnie badania interdyscyplinarne stanowią swego rodzaju standard, ale w latach 90-tych takie podejście łączenia ze sobą różnych dziedzin było nawet nie do pomyślenia. Jednakże ja upatrywałam w nim nie tylko szanse na poszerzanie perspektyw badawczych, ale i kryjący się za tym ogromny potencjał. Z upływem czasu tematyka moich interdyscyplinarnych prac naukowych stopniowo ewoluowała w kierunku poszerzonej interdyscyplinarności (multidyscyplinarności), łącząc fizykę, chemię, informatykę, farmację, biofizykę, a w ostatnich latach również matematykę, meteorologię, klimatologię, astronomię oraz ochronę środowiska.

Abstract: Droplets covered by micro- and nanoparticles have recently received considerable research interest, as they are promising for various practical applications, such as in food technology, the oil industry, biofuel processing, and improving pharmaceutical products. Moreover, such droplets possess characteristics that make them useful as experimental model systems for studying, for example, particle effects on interfacial tension, particle crystal growth and ordering or particle-layer buckling on curved interfaces, particle assembly and rearrangement on droplets’ surfaces, and particle detachment from droplets. Particle-covered droplets can additionally be employed for fabricating porous structures, granular or colloidal capsules of different mechanical properties, morphologies, or shapes, and adaptive structures. In this context, broadening one’s knowledge of particle-covered droplet stability, deformation, and surface-particle manipulation is essential to further developing the above-mentioned research areas. The deformation of droplets can be induced and investigated using various experimental tools, including atomic force microscopes, microfluidic devices, or mechanical shearing. For manipulating the surface or bulk particles, many physical or chemical approaches exist, such as pH-controlled particle assembly, acoustic wave–induced bulk and surface particle convection, magnetic field–directed particle assembly, and electric field–assisted particle arrangements. In this seminar I will demonstrate how we utilized various electric field phenomena to study the behaviour of particle-covered droplets subjected to electric fields, including steady-state deformation and transient deformation of such droplets, as well as the mechanics and rheological properties of particle shells formed on droplets. I will also show that electric fields can be used for manipulating particles in the bulk and at the surface of the droplet by exerting forces that were acting on them either directly, e.g. through particle motion via dipolar forces, or indirectly, e.g. by particle convection through electric field–induced liquid flows.

Abstract: Adherence of pathogens such as bacteria and viruses on various surfaces routinely leads to subsequent transmission to new hosts, significantly promoting the proliferation of potentially harmful organisms. This sequence is particularly worrisome in the case of antibiotic-resistant pathogens, which are becoming a global threat to human health. According to the Centers for Disease Control and Prevention, 1 out of every 20 hospital patients is affected by nosocomial infections, subsequently resulting in 100,000 deaths annually in the United States alone. Out of these, about 23,000 deaths are attributed to drug-resistant pathogens such as methicillin-resistant Staphylococcus aureus (S. aureus) or vancomycin-resistant Enterococcus faecium (E. faecium). Strains referred to as “nightmare bacteria” with highly elevated resistance to last-resort antibiotics have been reported all around the world in 2017. While silver, copper, zinc oxide or titanium dioxide have been used as surfaces or introduced as nanoparticles into a broad range of substrates to serve as antimicrobial agents and eradicate a wide range of pathogens, they all suffer from eventual reservoir depletion, and they tend to be pathogen- or condition-specific. Moreover, if not covalently bound or tightly embedded, these nanoparticles can leach into the environment and introduce additional health concerns. In this study, we discuss a photodynamic polymer composed of an olefinic thermoplastic elastomer modified with zinc tetra(4-N-methylpyridyl)porphine (ZnTMPyP⁴⁺), a photoactive antimicrobial, and demonstrate that this combination is remarkably effective at inactivating 5 bacterial strains, including S. aureus and Escheria coli (E. coli) often associated with food poisoning, and 2 different viruses, including Human adenovirus-5, upon exposure to non-coherent light at an intensity of 65-80 mW/cm² for 60 min. By achieving antibacterial and antiviral efficacies of at least 99.89% and 99.95%, respectively, this methodology based on the light-induced creation of singlet oxygen constitutes a non-specific and highly successful route by which to eliminate harmful pathogens by simple exposure to visible light and oxygen.

Abstract: Using computers means work for muscular systems, e.g. the intra-ocular muscle of the focussing system in the eyes, the extra-ocular muscles for moving the eyes, the muscles of the neck and the back. These physiological systems have properties that have developed during evolution in natural environments. For comfortable computer work, these individual physiological functions should be considered when arranging and designing the computer workstation for the individual user. Optometry provides appropriate eye glasses for clear vision.
[1] Jaschinski W (2017) Individual Objective and Subjective Fixation Disparity in Near Vision. PLoS ONE 12(1).
[2] Schroth, V.; Joos, R.; Jaschinski, W.: Effects of prism eyeglasses on objective and subjective fixation disparity. PLoS ONE 10: e0138871 (29 pp.) (2015)
[3] Weidling P, Jaschinski W: The vertical monitor position for presbyopic computer users with progressive lenses: how to reach clear vision and comfortable head posture. Ergonomics 58: 1819-1829 (2015)
[4] Jaschinski W, König M, Mekontso TM, Ohlendorf A, Welscher M: Comparison of progressive addition lenses for general purpose and for computer vision: an office field study. Clin Exp Optom 98: 234-243 (2015)
[5] König M, Haensel C, Jaschinski W: How to place the computer monitor: measurements of vertical zones of clear vision with presbyopic corrections. Clin Exp Optom 98: 244-253 (2015)

Abstract: The forms of so-called “quantum matter” – where quantum effects are crucially manifested at the macroscopic scale – range from phases of “traditional” strongly correlated many body systems to exotic topological systems. Research on two parallel wide classes of systems are providing access and understanding to various aspects of many body physics – (i) so called quantum simulators of matter (“idealized materials”), and of course (ii) various real materials, controlled in novel ways. In particular, quantum simulators in controlled environments based on platforms of ultracold particles trapped in optical lattices, ion traps, nano-photonic systems can be engineered to access often extreme parameter regimes rarely accessible before in real materials, using control via light or magnetic fields. Similarly, advances in ultra-fast spectroscopy are facilitating the manipulation of real materials at a microscopic level using light instead of the more traditional control of pressure, temperature etc. These new ways of controlling and manipulating matter pose theoretical challenges. In this seminar, I will summarize some results of research that I have been part of in this exciting field that will constitute my Habilitation dissertation – all of which concern the description of properties and control of long range ordered phases in d=1 or 2 dimensional systems. In particular, I will talk about: (i) engineering extreme correlated hopping for ultra-cold atoms and associated physical properties (ii) non-trivial gauge field effects in an exemplary one-dimensional system (iii) effects of gauge fields in a spinor boson gas (iv) proximity effects in an engineered bilayer system and (v) control of orbital order in a paradigmatic manganite.

Streszczenie: Sygnały chaotyczne to sygnały opisane przez deterministyczne układy równań różniczkowych, których rozwiązaniem jest nieregularny przebieg zmiennych w czasie. Jedną z miar ukrytej, częściowej regularności jest Wymiar Korelacyjny (d, Correlation Dimension). Dostępne w literaturze algorytmy wyznaczania tego parametru dają jednak błędne wyniki w przypadku sygnałów wysoko wymiarowych, czyli o złożoności przekraczającej d=5. Prezentacja przedstawia wyniki wielu symulacji numerycznych i analiz wyjaśniających przyczyny błędów estymacji dla sygnałów wysoko wymiarowych oraz poprawne sposoby wyznaczania tego parametru. Analiza skupiona była zarówno na poprawieniu dokładności wyznaczania d, oszacowaniu dokładności tej estymacji, jak i na przyspieszeniu obliczeń, które w przypadku sygnałów wysoko wymiarowych są bardzo czasochłonne. Końcowym efektem pracy jest w dużej mierze nowy algorytm, który wyznacza d z dużą dokładnością w znacznie krótszym czasie i który zaimplementowany jest w zestawie funkcji Matlab udostępnionych do swobodnego wykorzystania. Metoda może mieć zastosowanie w wielu dziedzinach nauki, w których mamy do czynienia z układami chaotycznymi: w fizyce, chemii, biologii, ekonomii, meteorologii itp.

Abstract: Different definitions of higher-order sub-Poissonian-like fields based on the moments of integrated intensity, photon number, integrated-intensity fluctuation, photon-number fluctuation and using the elements of photocount (photon-number) distributions will be introduced. Their mutual relations will be elucidated. Using the set of potentially sub-Poissonian fields obtained by post-selection from a twin beam based on photon-number-resolving detection their power to experimentally indicate non-classicality will be discussed. The generation of sub-Poissonian-like optical fields up to the fifth-order in intensity moments and up to the eleventh-order in the elements of photocount distribution will be mentioned.

Abstract: After 55 years since its formulation, the Hubbard model keeps many problems open till present days. We discuss main reasons for the difficulty to access particular regimes of this simple model even with modern computational possibilities. It will be shown that the Hubbard model is universal in the sense that it can describe large classes of materials and strongly-correlated many-body phases of interest, in particular, high-temperature superconductors and excitonic insulators. For these two cases, several recent experimental achievements and current level of theoretical description will be pointed out. With all problems in mind, a natural question arises: “Can universal quantum simulators or quantum computers help to gain further physical insights in the Hubbard model?” According to recent progress in these fields, we tend to answer “yes”, but there are still many challenges on the way.

Abstract: The rate of progress has been remarkable. Only a year and a half ago, we put the IBM Q experience prototype 5-qubit machine in the cloud, and made it available for the world to use, explore, and learn from. A year later, we added a second device with 16 qubits. Today, more than 60,000 users from more than 1,500 universities, 300 high schools, and 300 private institutions have registered for accounts on the IBM Q experience, and collectively run 1.7 million experiments. The members of the research community have also published more than 35 research papers using our platform as a testbed for ideas. This is only the beginning.

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Streszczenie: Podczas prezentacji zostaną przedstawione wyniki obserwacji oraz modelowania układów wielokrotnych gwiazd zawierających parę zaćmieniową. W ramach wprowadzenia zostanie omówiony proces powstawania gwiazd w obłokach molekularnych. Przedstawione będą różne typy obiektów oraz interesujące wyniki obserwacyjne z ostatnich lat. Dynamika i stabilność takich układów oraz możliwość obecności planet jest kolejnym ważnym problemem. Tematyka powstawania gwiazd jest ściśle związana z badaniami układów wielokrotnych. Obserwacje dostarczają informacji które pozwalają zweryfikować współczesne teorie formowania się gwiazd. Przedstawione będą instrumenty badawcze dzięki którym zgromadzono dane spektroskopowe i fotometryczne niezbędne do modelowania pięciu wybranych układów wielokrotnych. Omówione zostaną podstawowe zastosowane metody – pomiarów prędkości radialnych (efekt Dopplera) oraz modelowania par zaćmieniowych. Dla pięciu badanych układów udało się odkryć nowe składniki spektroskopowe, wyjaśnić hierarchie układów oraz otrzymać parametry orbitalne, takie jak okresy, rozmiary, mimośrody oraz nachylenia. Ponadto wyznaczono masy, promienie, temperatury, kształt oraz skład chemiczny składników par zaćmieniowych. Na podstawie tych wyników można określić status ewolucyjny badanego obiektu oraz wyznaczyć jego odległość.

Streszczenie: Nauki biologiczne można podzielić na biochemię, genetykę, biologię molekularną i epigenetykę. Generalnie biologia molekularna analizuje znane produkty znanych genów, biochemia zajmuje się badaniami znanych produktów nieznanych genów a zadaniem genetyki jest analiza znanych genów nieznanych produktów. Poznańie sekwencji nukleotydowej ludzkiego genomu w 2003 roku było jednym z największych osiągnięć genetyki. Genom człowieka składa się z ponad 3 miliardów par zasad i zawiera ok. 21000 genów kodujących białka, co stanowi zaledwie 2% genomu. Liczba genów człowieka jest tylko o około 50 większa od liczby genów szympansa, natomiast bakteria Escherichia coli ma 4300 genów, drożdże piwne – 6300 genów, rzodkiewnik pospolity – 25000, a ryż – 50000. Dwoje niespokrewnionych ludzi wykazuje identyczność 99,9% sekwencji nukleotydowej DNA. W całej populacji ludzkiej różnice dotyczą tylko 0,3% sekwencji genomu. Pozostałe 98% genomu, choć nie koduje białek (są tam m.in. mobilne elementy genetyczne, pseudogeny czy introny) jest tak samo ważna dla funkcjonowania komórki. Część pseudogenów pozostaje transkrypcyjnie nieaktywna, ale z większości powstają RNA, które nie są przepisywane na białko, ale mogą regulować ekspresję genów. Każda komórka naszego organizmu zawiera ten sam genom (DNA), ale mimo tego komórki bardzo się od siebie różnią. W komórce istnieją mechanizmy powodujące zmiany epigenetyczne (epi: poza, ponad), które wpływają na ekspresję genów ale nie zmieniają sekwencji DNA. Jednym z mechanizmów epigenetycznych jest metylacja DNA, a drugi modyfikacja (metylacja, acetylacja) histonów. Modyfikacje epigenetyczne, są często efektem reakcji organizmu na zmieniające się warunki otoczenia oraz decydują o jego możliwościach adaptacyjnych. Poszukiwania epigenetyczne polegają na identyfikacji elementów chemicznych, które modyfikują genom, zarządzają komórkami, i zmieniają długoterminową ekspresję genów. Okazało się, że nie tylko substancje chemiczne ale również uwarunkowania społeczne mogą wpływać na jej zakres. Modyfikacje epigenetyczne mogą się pojawić w wieku dorosłym, młodzieńczym, a nawet in utero. W konsekwencji, określone wydarzenie z dzieciństwa może zmienić sposób, w jaki geny reagują w innej sytuacji w wieku dorosłym. Przechodząc na grunt medycyny, zauważono, że w procesie nowotworzenia następuje obniżenie globalnego poziomu metylacji DNA oraz podwyższenie metylacji promotorów genów supresorowych a także modyfikacje histonów, co prowadzi do zmian w ekspresji genów. Bazując na tych obserwacjach, podejmowane są próby terapeutycznego wykorzystania mechanizmów epigenetycznych ograniczając negatywny wpływ demetylacji DNA czy acetylacji histonów.

Abstract: Multiparticle entangled states, essential ingredients for modern quantum technologies, are routinely generated in experiments of atomic Bose-Einstein condensates (BECs). However, entanglement in ultracold interacting Fermi gases has not been exploited yet. Here, using a theory of composite bosons we show that many-particle entanglement between two fermionic ensembles localized in spatially separated modes can be generated by splitting an ultracold interacting Fermi gas in the (molecular) BEC regime. This entanglement relies on the fundamental fermion exchange symmetry of molecular constituents and might be used for implementing quantum information tasks such as Bell test of quantum nonlocality. We also predict that large ensembles, of the order of 10⁵ fully entangled fermionic atoms, could be generated in current experiments of ultracold interacting Fermi gases.

Streszczenie: Polieny, włączając karotenoidy oraz antybiotyk amfoterycyna B, odgrywają różne, niezwykle ważne role biologiczne. W układach naturalnych ich funkcjonowanie opiera się głównie na modyfikacji fizycznych właściwości błon oraz protekcyjnym działaniu antyoksydacyjnym. Organizacja tych cząsteczek w błonach lipidowych związana jest ściśle z mechanizmami molekularnymi odpowiedzialnymi za funkcje jakie odgrywają one w organizmach żywych. Komplementarne zastosowanie spektroskopii Ramana i spektroskopii fluorescencyjnej w badaniach polienów pozwala na unikalną analizę oraz obrazowanie struktur biologicznych w mikroskali. Podejście opierające się na równoczesnym użyciu dwu technik mikroskopowych wykorzystane zostało, między innymi, do badań organizacji molekularnej, lokalizacji oraz orientacji karotenoidów, a także antybiotyku polienowego. Podczas wystąpienia zaprezentowane zostaną wyniki badań oraz analizy przeprowadzone dla polienów (luteiny, zeaksantyny, amfoterycyny B) wbudowywanych do modelowych błon lipidowych w postaci bardzo dużych, jednowarstwowych struktur liposomowych (GUV ang. Giant Unilamellar Vesicles) formowanych z lecytyny. Dane uzyskane z pomiarów fluorescencyjnych umożliwiły określenie lokalizacji cząsteczek, a także dały podstawę do stwierdzenia jaką formę organizacji molekularnej przyjmują analizowane związki. Szczegółowa analiza z wykorzystaniem oryginalnej metody pozwoliła precyzyjnie wyznaczyć orientację polienów względem osi normalnej do błony lipidowej. Spektroskopia ramanowska, poza lokalizacją polienów w strukturach lipidowych, umożliwiła uzyskanie informacji o formach stereoizomerycznych karotenoidów występujących w badanych układach, a także o ich rozmieszczeniu w obrębie analizowanego systemu. Przedstawione badania pozwalają, między innymi zrozumieć rolę jaką odgrywają luteina i zeaksantyna w plamce żółtej oka ludzkiego oraz jakie jest ich znaczenie w procesie nieodwracalnej utraty wzroku w wyniku starczego zwyrodnienia siatkówki (AMD, ang. Age-related Macular Degeneration). Dzięki uzyskanym wynikom zweryfikowano hipotezy dotyczące funkcji ochronnych pełnionych przez karotenoidy na poziomie molekularnym. Przeprowadzone badania antybiotyku polienowego amfoterycyny B pozwoliły zidentyfikować molekularne determinanty toksyczności tego leku dla pacjentów.

Abstract: The spectral-temporal degree of freedom of light has recently been recognized as a promising platform for encoding and transmission of quantum information. This requires the ability to modify the spectral and temporal profiles of single-photon light pulses. During the seminar I will talk about the methods of spectral modification of quantum light using electro-optic phase modulation. This method allows to change the time-spectral profile of the light pulse in a deterministic and, in principle, unitary way, i.e. without the use of filtering or amplification. In particular, I will present experimental results on efficient modification of the spectral bandwidth of single-photon pulses of light and discuss their significance in the context of the development of quantum networks.

Streszczenie: Organiczne urządzenia optoelektroniczne – diody elektroluminescencyjne, ogniwa fotowoltaiczne oraz fotodiody – wykazują szereg niezwykłych właściwości, takich jak elastyczność, lekka waga czy też możliwość wytwarzania elementów o dużej powierzchni tanimi metodami drukarskimi, które są nieosiągalne dla elektroniki nieorganicznej. Mimo to, drukowana elektronika organiczna nie znalazła jeszcze szerokiego zastosowania, gdyż parametry pracy tak wytworzonych urządzeń nie spełniają wymagań użytkowników. Seminarium będzie poświęcone metodzie optymalizacji struktury organicznych i hybrydowych fotodetektorów, w celu uzyskania urządzeń wykazujących dobre cechy użytkowe. Metoda ta jest oparta na analizie zjawisk fizycznych wpływających na parametry pracy fotodiod takich jak: generacja ekscytonów i ich dysocjacja na swobodne nośniki ładunku, rekombinacja, pułapkowanie i ruchliwość nośników ładunku, oraz przepływ prądów ograniczonych ładunkiem przestrzennym. Taka analiza będzie przeprowadzona na przykładzie dwóch klas urządzeń: fotodetektorów hybrydowych, w których warstwę aktywną stanowiły układy organiczno-nieorganiczne oparte na mieszaninie polimeru z nieorganicznymi nanocząstkami, oraz fotodetektorów polimerowych wykorzystujących odpowiednio zaprojektowane kopolimery donorowo-akceptorowe, które dzięki wąskiej przerwie energetycznej są zdolne do absorpcji światła z zakresu bliskiej podczerwieni. Proces optymalizacji obejmował także dobór warstw blokujących niepożądany przepływ ładunku, których zastosowanie umożliwia uzyskanie zbalansowanego transportu elektronów i dziur oraz obniżenie prądów ciemnych co zwiększa czułość fotodiod. Na seminarium zostaną zaprezentowane także wstępne wyniki druku warstw aktywnych i opracowanych kompozycji atramentów i omówione będą perspektywy rozwoju drukowanej elektroniki organicznej.

Abstract: The presentation will be devoted to investigation of structure, physical-mechanical and tribological properties of multielement NbN, Nb-Si-N, Nb-Al-N, (Ti-Zr-Hf-V-Nb)N and (Ti-Zr-Hf-V-Nb-Ta)N coatings, as well as multilayered TiN/MoN, TiN/ZrN and MoN/CrN coatings with various bilayer thickness, deposited using PVD methods (vacuum-arc evaporation of cathode or reactive magnetron sputtering). Influence of deposition conditions on microstructure and properties of the coatings will be discussed. In addition, influence of high-temperature annealing and high-dose ion implantation of Au- and N+ ions will also be covered within the presentation.

Streszczenie: Tematyka wystąpienia obejmuje kompleksowe badania struktury nadsubtelnej (w wybranych przypadkach również z dodatkowym rozszczepieniem zeemanowskim) poziomów elektronowych atomu i jonu terbu oraz atomu holmu, prowadzone metodą fluorescencji wzbudzonej wiązką laserową, z użyciem jednomodowych laserów przestrajalnych. Kluczowe w badaniach jest wykorzystanie m.in. przestrajalnego lasera barwnikowego generującego w trudno dostępnym zielonym zakresie spektralnym, pompowanego optycznie laserem diodowym. Istotny postęp w analizie struktury elektronowej dla wspomnianych pierwiastków, uzyskany w oparciu o wspomniane badania eksperymentalne, może stanowić podstawę poszukiwania zastosowań w kwantowej inżynierii i metrologii. Dla atomu holmu zaproponowano schematy poziomów do pomiaru zmian czasowych stałej struktury subtelnej. Rozważane są w dalszej perspektywie również inne zastosowania dotyczące atomu terbu.

Abstract: Ultrafast structural dynamics is an emerging field aiming to deliver a detailed understanding of the elementary steps in reacting chemical species, which involve changes in their nuclear, electronic and spin states. Such processes are vital ingredients in chemistry and biology, but also in technological applications, including efficient charge transport in light harvesting molecules and ultrafast switchable molecular magnets. In order to unravel this complex dynamic behavior we have implemented a suite of ultrafast X-ray spectroscopic and scattering tools to zoom into both the electronic and nuclear structures, with the goal to ultimately deliver a molecular movie of ongoing chemical processes. In view of the many potential applications in chemical and biological dynamics it is desirable to increase the sensitivity level of such experiments as well as to decrease the time resolution into the femtosecond time domain. In this talk I will present our benchmark results using a versatile setup that permits simultaneous measurements of ultrafast X-ray absorption and emission spectroscopies combined with X-ray scattering, which has been recently implemented at different synchrotrons and X-ray Free Electron Lasers. It has been applied to study different photochemical reactions, ranging from nascent radicals in solution, molecular spin transitions, and ligand exchange reactions, to photocatalytic systems, with the goal to deliver a deeper understanding of the elementary steps in chemical reactivity.

Abstract: Asteroids, space rocks orbiting the Sun, are very diverse in composition. While the largest of them (500-1000 km) are spheroidal bodies, and the middle-sized ones (0.1-500km) are gravity-dominated, irregular rubble-piles, the smallest asteroids (D < 0.1km) are either monolitic bodies or boulders held together by the forces of cohesion. Observations suggest that many of the smallest asteroids can be surprisingly weak bodies evolving under the influence of the solar radiation. Since some of them come close to the Earth, they can be easily observed or even visited by space probes. This way they can serve as a laboratory for testing physical phenomena controlling the evolution of the asteroids not only in our Solar System, but also those orbiting around other stars. The talk will be targeted for non-astronomers with the emphasis on the physical phenomena in the low-gravity environment. I will interpret images obtained from space probes, present shape models used for testing theories and arrive at conclusions about the internal structure and evolution of the smallest asteroids.

Abstract: As a liquid, water plays a critical role in biological systems. Its permanent dipole moment can interact favorably with charged species. Water is an excellent hydrogen bonding solvent. It has a balanced number of hydrogen bond donors and acceptors and it has the smallest moment of inertia among small molecule polar liquids. As such it demonstrates the fastest solvent relaxation dynamics. In the liquid phase H₂O molecules form a disordered fluctuating network of intermolecular hydrogen bonds. The motions of biomacromolecules depend on the structure and dynamics of water. These motions take place over a many time-scales: from ns (diffusion of H₂O in the first solvation shell of protein), through ps (amino-acid side motions) to sub-ps (librational and phonon-like motion of H₂O). The motions in a large range of frequencies can be studied by the OKE, the anisotropic Raman scattering and the dielectric techniques including THz-TDS. Using these methods one can observe changes in the spectra of biomacromolecules in water solution in the range 10 GHz-30 THz. In the lecture the fundamentals of THz radiation, as well as optical and THz Kerr effect will be reminded. THz–OKE measurements of three water samples of deionized, distilled and buffered (PBS) water will be reported and analyzed. These media were chosen in order to study the effect of ions presence on water behavior in the ultrafast time scale. The water most interesting from the point of view of living cells studies is the one significantly ionized. Therefore, discrimination between ultrafast effects resulting from internal H₂O properties from those resulting from H₂O – ions interactions are very important. These two effects may be connected to difference in the fluctuations of the network of intermolecular hydrogen bonds of water molecules in the presence or absence of ions and cations in solution. These fluctuations are expected to significantly alter water birefringence amplitude and its dynamics.

Streszczenie: Na seminarium zostaną przedstawione badania cienkich warstw stopów Heuslera Co₂Fe_xMn_1−xSi (CFMS) i Co₂FeGa_0.5Ge_0.5 (CFGG). Wymienione wyżej stopy charakteryzują się wysoką polaryzacją spinową i są dobrymi kandydatami do zastosowań, między innymi w spintronice. W tych materiałach ważną rolę odgrywają ich właściwości magnetosprężyste, anizotropia magnetyczna oraz właściwości dysypatywne. Przede wszystkim rozważany jest wpływ skończonej grubości warstwy magnetycznej a także zastosowania różnych warstw buforowych oraz powierzchniowych. Będą także przedstawione badania szeregu dodatkowych parametrów charakteryzujących warstwy magnetyczne, takich jak wartości całki wymiany, uporządkowanie chemiczne oraz parametry tłumienia magnetycznego. Szczególnie zostanie przedstawiona unikatowa technika Strain Modulated Ferromagnetic Resonance (SMFMR), która umożliwia badania właściwości magnetosprężystych cienkich warstw magnetycznych.

Abstract: Tematyka seminarium obejmuje aspekty biomechaniki, optyki i dynamiki gałki ocznej mające związek z powstawaniem obrazu w układzie optycznym oka. Wykład przybliży cel naukowy badań parametrów mechanicznych tkanek oka i ich skorelowania z procesami fizjologicznymi i rozwojem patologii (w tym jaskry) w oku. Oko człowieka jest strukturą, w której występuje ścisła korelacja pomiędzy właściwościami mechanicznymi i refrakcyjnymi oka. Oznacza to, że z powodów czysto optycznych parametry strukturalne – geometryczne i materiałowe – muszą spełniać określone warunki. Określenie tych warunków umożliwia przewidywanie procesów fizjologicznych oraz diagnostycznych, w tym skutków patologii oka. Część chorób oka ma etiologię mechaniczną, do takich należy jaskra. Wiedza z zakresu mechaniki obejmuje zarówno zjawiska fizjologiczne zachodzące wewnątrz gałki ocznej, jak również efekty działań diagnostycznych. Jednym z takich działań jest procedura pomiaru ciśnienia wewnątrzgałkowego (tonometria). Wszystkie realistyczne modele gałki ocznej w tonometrii i chirurgii refrakcyjnej muszą dzisiaj uwzględniać zarówno zmienną grubość powłok oka, jak również nieliniowość ich właściwości materiałowych. Prezentowane w literaturze modele biomechaniczne oka, wykorzystywane w diagnostyce, stworzono głównie pod kątem zastosowania albo w tonometrii albo w korekcji refrakcji, natomiast nie uwzględniają one związku pomiędzy tymi dwoma zastosowaniami. Ponadto istnieją też inne czynniki/procesy fizjologiczne (np. puls oczny, akomodacja, zaćma, jaskra itp.), które należy uwzględnić w modelowaniu i diagnostyce oka. Brakuje dzisiaj kompaktowego modelu, zdolnego pełnić wszystkie powyższe funkcje. Na seminarium zaprezentowane będą wyniki badań zmierzające do określenia takiego modelu gałki ocznej.

Abstract: Generation and manipulation of tiny aqueous compartments by external flow finds numerous applications in analytical sciences where each compartment (droplet) may be used as a separate chemical- or bio-reactor. In this talk I will focus on material-science perspective on droplet microfluidics in which individual compartments are treated as building blocks of larger structures. It is known that concentrated emulsions behave like soft-solids and exhibit both strong plasticity and viscoelasticity. Microfluidics opens new perspectives on studying these tissue-like materials at mesoscale: the possibility of tracking individual droplets gives a unique insight into the process of their self-assembly into ordered, reconfigurable structures. In particular, we observe a variety of small, compact clusters with well-defined point-group symetries. In presence of external flow the structures get stretched into semi-solid granular threads with long-range translational order. Finally, we study relaxation dynamics of large spheroidal aggregates composed of hundreds or thousands of droplets (10^2 </N/<10^4 ) and compare the obtained results with similar experiments on cell aggregates reported previously in the literature. We try to draw possible mechanistic analogies between droplet-based structures and actual biological micro-tissues.

Abstract: Nanojunctions containing individual impurities strongly tunnel coupled to leads have proven to be an excellent test-bed for studying quantum many body effects in electronic transport, among which the Kondo effect is one of the most prominent ones. The role of such impurities can be played, for instance, by quantum dots, magnetic atoms or molecules. A proper understanding of the effect of charge and spin correlations on electronic transport is especially sought for devices based on large-spin (S>1/2) impurities exhibiting spin anisotropy. This stems from the fact that such systems are a suitable platform for applications in emerging technologies for storage and processing information. In this talk, I will address different effects that can arise in strongly correlated spin-polarized transport through junctions with spin-anisotropic impurities. Specifically, I will discuss the influence of spin anisotropy on transport characteristics, as well as demonstrate how to control spin anisotropy of an impurity with the aid of spintronic exchange fields.

Abstract: Over the last decade, the design of molecular structures allowing the control of a given property (electron transfer, magnetism, catalysis) using an external stimulus, such as electron-exchange, constitutes an important goal, both from the fundamental and applied standpoint. The facile and reversible M(II)/M(III) redox process exhibited by several Fe(II) and Ru(II) σ-arylacetylides fragments of formula “L₄XM(C ≡ C-Ar)-” can conveniently be used to reach molecular assemblies with large and redox-switchable third-order nonlinear optical (NLO) properties such as 1 or 2 [1,2]. Finally, attempts to extend this concept to fluorescence or two-photon absorption, or to access related electroswitchable materials will be reported.

[1] M. P. Cifuentes, M. G. Humphrey, J. P. Morall., M. Samoc, F. Paul, T. Roisnel, C. Lapinte Organometallics. 2005, 24, 4280-4288 (and refs. cited).
[2] (a) Gauthier, N.; Argouarch, G.; Paul, F.; Toupet, L.; Ladjarafi, A.; Costuas, K.; Halet, J.-F.; Samoc, M.; Cifuentes, M. P.; Corkery, T. C.; Humphrey, M. G. Chem. Eur. J. 2011, 17, 5561. (b) N. Gauthier , C. Olivier , S. Rigaut , D. Touchard , T. Roisnel , M. G. Humphrey , F. Paul Organometallics 2007, 26, 1063.
[3] N. Gauthier, G. Argouarch, F. Paul, M. G. Humphrey, L. Toupet, Ababou-Girard, S., H. Sabbah, P. Hapiot, B. Fabre, Adv. Mater. 2008, 20, 1952.

Abstract: [PDF]  Wybrane do badań właściwości fotofizycznych związki z grupy 1,3,4-tiadiazoli wykazują głównie działanie neuroprotekcyjne, przeciwgrzybiczne oraz antynowotworowe. Badania spektroskopowe związków wykonane metodami spektroskopii molekularnej pozwoliły zaobserwować, w przypadku części struktur w środowisku wodnym, bardzo interesujące zjawisko podwójnej fluorescencji. Efekt ten może być indukowany zmianą pH roztworów wodnych, temperatury oraz efektami agregacyjnymi. W przypadku analogicznych pomiarów widm związków wykonanych w różnych rozpuszczalnikach organicznych, obserwowano tylko pojedyncze pasmo fluorescencji. Badania różnych analogów tej grupy związków wykazały, że można indukować wyżej wymieniony efekt również w rozpuszczalnikach oraz modelowych układach biologicznych poprzez zmianę stężenia związku lub modyfikację jego podstawnika. W wodnych roztworach metanolu o określonej kwasowości obserwowano najczęściej dwa osobne, częściowo pokrywające się, pasma fluorescencji. W oparciu o dane krystalograficzne i badania fluorescencyjne monokryształów związków stwierdzono, że mogą one przyjmować dwie konformacje w zależności od orientacji przestrzennej grupy -OH znajdującej się w pozycji orto względem pierścienia tiadiazolowego. W zależności od przyjmowanej konformacji w widmach emisji obserwujemy efekt podwójnej fluorescencji lub dwa częściowo pokrywające się pasma emisji. Szereg badań wykonanych metodami spektroskopowymi takimi jak technika RLS, pomiary czasów życia fluorescencji oraz pomiary widm emisji i wzbudzenia fluorescencji wskazują, że w wyjaśnieniu natury zaobserwowanych efektów fluorescencyjnych pomocna jest zarówno wiedza na temat konformacji molekuł jak i występowania efektów agregacyjnych w roztworze. Układ w którym cząsteczki przyjmują konformację z grupą -OH z pierścienia rezorcylowego ustawioną bliżej atomu azotu z pierścienia 1,3,4-tiadiazolowego prawdopodobnie zwiększa możliwość wewnątrzmolekularnego przeniesienia ładunku i powstawania słabego stanu elektronowego związanego z tym przeniesieniem, prowadzącego w konsekwencji do powstawania efektu podwójnej fluorescencji tych cząsteczek, co potwierdzają obliczenia kwantowomechaniczne metodami [TD]DFT. Obie obserwowane konformacje odpowiednio stabilizowane przypuszczalnie może różnić też zdolność oddziaływań biologicznych. Warto podkreślić, że badania biologiczne tej grupy związków wykazały również grzybobójcze efekty synergistyczne z amfoterycyną B w stosunku do kilku szczepów grzybów patogennych w hodowlach in vitro.

Streszczenie: Konwersja energii słonecznej na energię w formie paliwa wydaje się być jednym z najbardziej obiecujących sposobów na zaspokojenie potrzeb energetycznych świata w przyszłości. Szczególnie duże nadzieje pokładane są w rozkładzie wody (water splitting) prowadzącym do gospodarki opartej na wodorze jako podstawowym paliwie. Opracowanie taniej, wydajnej i szybkiej metody produkcji wodoru, jest podstawowym warunkiem, który musi być spełniony by wodór mógł zastąpić bieżące nośniki energii. Obecne metody wykorzystywane do kierowanego światłem rozkładu wody podzielone mogą zostać na trzy grupy: metody termochemiczne, fotobiologiczne oraz fotokatalityczne. W ramach seminarium omówiona zostanie koncepcja fotokatalitycznej dekompozycji wody w układach barwnik/ tlenek grafenu/kompleks kobaltu – ich charakterystyka, właściwości oraz metodologia badań. Powierzchnia tlenku grafenu dzięki jego unikalnym właściwościom może zostać sfunkcjonalizowana za pomocą cząsteczek oraz nanomateriałów. Główna korzyść zastosowania takich hybryd wiąże się zachodzącym w nich transportem elektronu od wzbudzonej cząsteczki barwnika do katalizatora kobaltowego poprzez arkusz tlenku grafenu (GO), w wyniku czego następuje redukcja protonów i utworzenie wodoru cząsteczkowego.

Abstract: The maintenance of replication fork stability is essential for faithful genome duplication and suppression of carcinogenesis. In an effort to further our understanding of the mechanism of replication fork repair we performed an analysis of proteins recruited to DNA replication forks using the iPOND technique. This analysis identified EXD2, a nuclease that we have shown recently to promote DNA-end resection and homology-directed repair1, as a novel factor present at replication forks. EXD2 is required for efficient ATR activation and fork restart in response to replicative stress. Moreover, purified recombinant EXD2 can efficiently process synthetic DNA structures mimicking those that are generated at stalled/collapsed replication forks. In keeping with this, EXD2-deficient cells are sensitive to a plethora of agents that interfere with replication fork progression. Failure to timely complete DNA synthesis leads to the persistence of under-replicated DNA, which can manifest as anaphase bridges, 53BP1 OPT domains and/or cause formation of micronuclei. Consistent with EXD2’s role in promoting efficient genome duplication, we observe that EXD2-deficient or EXD2-nuclease dead cells display a significant increase in the frequency of all these markers. Thus, our data identify EXD2 as a novel component of the replication fork protection pathway. We propose that EXD2 processes stalled/collapsed replication forks and by doing so, promotes efficient fork restart assuring accurate completion of DNA replication. [1] R. Broderick et al., EXD2 promotes homologous recombination by facilitating DNA end resection, Nat Cell Biol 18, 271-280 (2016).

Abstract: Nowadays many inputs of phenomenological models are taken from lattice simulations of Quantum Chromodynamics. These numerical methods, based on Monte Carlo techniques, always stress their superiority against other approaches by arguing that all steps of computations are from first principles and truly non-perturbative. However many of the most precise results use in one way or another perturbation theory. In this talk I will try to explain the intertwinned relation between non-perturbative simulations and perturbation theory and discuss some of the modern techniques of getting perturbative results on a lattice.

Streszczenie: W ramach seminarium zostaną omówione wybrane metody obronne roślin takie jak szybki ruch związany ze składaniem liści, wytwarzaniem substancji trujących, lub zapachu, który przywabia owady drapieżne. Szczególna uwaga zostanie poświęcona roślinom owadożernym, których ruch pułapkujący bywa zaskakująco szybki (w czasie ok. 3 ms u Ultricularia inflata), co wymaga stosowania szybkich kamer (15000 klatek na sekundę). Omówione zostaną również aspekty związane z powabnością kwiatów zarówno w zakresie akustyki (liść o kształcie czaszy stanowi akustyczną echo-latarnię dla nietoperzy zapylających kwiaty Marcgravia evenia), jak i optyki (ubarwienie strukturalne płatków kwiatowych). Główną rolę ubarwienia kwiatów pełnią barwniki, spośród których dla betalain wykazaliśmy funkcję fotoprotekcyjną.

Streszczenie: Luminescencja jonów lantanowców (Ln³⁺) jest tematem intensywnych badań, ze względu na rosnące zapotrzebowanie domieszkowanych nimi materiałów w wielu dziedzinach. W odpowiednio zaprojektowanych materiałach luminescencja jonów Ln³⁺ jest wydajna i intensywna, a przede wszystkim możliwe jest uzyskanie procesu konwersji energii w górę – up-konwersji (UC, ang. up-conversion). Zjawisko to odpowiada nieliniowemu procesowi absorpcji dwóch lub większej ilości fotonów w wyniku której następuje emisja promieniowania o energii wyższej niż zaabsorbowanego. Od kilku lat obserwuje się wzrost zainteresowania nanocząstkami wykazującymi UC, głównie ze względów na szerokie zastosowania w medycynie i biologii. Jednymi ze związków charakteryzującymi się właściwościami umożliwiającymi uzyskanie UC są nieorganiczne fosforany, wanadany i fluorki. Odpowiednia metoda syntezy, środowisko reakcji oraz dobór reagentów umożliwiają uzyskanie produktów o niewielkim rozmiarze krystalitów (< 50 nm). Otrzymano szereg nanomateriałów opartych o związki typu REPO4, REVO₄, SrF₂, LuF₃, NaLuF₄ oraz MRE₂F₇ (gdzie M = Ca, Sr, Ba; RE = Y, La, Gd, Lu), domieszkowanych jonami Yb³⁺ i Ho³⁺, Er³⁺, Tm³⁺, Tb³⁺ lub Eu³⁺. Otrzymane produkty scharakteryzowano pod względem ich struktury i morfologii oraz składu pierwiastkowego. Najważniejszym elementem przeprowadzonych badań było określenie właściwości spektroskopowych otrzymanych materiałów. W celu otrzymania pełnej charakterystyki luminescencyjnej otrzymanych produktów wykonano pomiary widm wzbudzenia (także w zakresie podczerwieni) oraz emisji, a także zaników emisji oraz zależności intensywności luminescencji od mocy (lub energii) promieniowania wzbudzającego. Pozwoliło to na Poznańie procesów zachodzących w otrzymanych materiałach, zaproponowanie mechanizmów tych procesów, a także na optymalizację badanych układów pod względem intensywności luminescencji.

Abstract: Understanding the robustness of topological phases of matter in the presence of strong interactions, and synthesising novel strongly-correlated topological materials, lie among the most important and difficult challenges of modern theoretical and experimental physics. The synthetic Creutz-Hubbard ladder is a paradigmatic model that provides a neat playground to address these challenges, including the generation of flat bands as well as of non-doubled Dirac dispersion relations. In [1], we present a theoretical analysis of the competition between correlated topological phases and orbital quantum magnetism in the regime of strong interactions at half-filling. We predict topological quantum phase transitions for weak and intermediate interactions with different underlying conformal field theories (CFTs), i.e. Dirac versus Majorana CFTs. In [2], we study the response of an interacting system of Dirac-Weyl fermions confined in a one-dimensional (1D) ring: we show that tuning of interactions leads to a unique many-body system that displays either a suppression or an enhancement of the Drude weight—the zero-frequency peak in the ac conductivity—with respect to the non-interacting value. Both studies are furthermore confirmed and extended by extensive numerical simulations based on matrix product states (MPS) and binary Tree Tensor Networks (bTTN). Moreover we propose how to experimentally realize this model in a synthetic ladder, made of two internal states of ultracold fermionic atoms in a one-dimensional optical lattice.

[1] J. Jünemann, et al., PRX 7, 031057 (2017)
[2] M. Bischoff, et al., arXiv:1706.02679

Streszczenie: Podczas seminarium ogólnie omówię tematykę moich badań, która dotyczy teoretycznej analizy własności transportowych skorelowanych układów nanoskopowych. Następnie, bardziej szczegółowo, przedstawię kilka najważniejszych zagadnień, którymi zajmowałem się po uzyskaniu stopnia naukowego doktora habilitowanego. W szczególności przedstawię rezultaty dotyczące badania różnych egzotycznych stanów Kondo w złożonych układach kropek kwantowych, omówię także badania dotyczące stanów związanych Andreeva w hybrydowych układach nanoskopowych, a także badania związane z kwazicząstkami Majorany.

Streszczenie: Koncepcja fenomenologicznych uniwersaliów wprowadzona przez Castorinę, Delsanto i Guiot (CDG) [1], umożliwia generowanie funkcji i modeli opisujących ewolucję w czasie układów biologicznych, takich jak organy, organizmy, ekosystemy, czy nowotwory. W zależności od stopnia złożoności (nieliniowości) można badane układy sklasyfikować jako U0, U1 i U2, którym odpowiadają funkcje biologicznego wzrostu: eksponent (U0), Gompertza (U1), Westa-Browna-Enquista, Richardsa i von Bertalanffy’ego (U2). Referat prezentuje prostą modyfikację klasycznego schematu CDG [2,3], która pozwala na uzyskanie kwantowych rozwiązań równań Schrödingera i Feinberga-Horodeckiego dla oscylatora harmonicznego oraz oscylatorów anharmonicznych, reprezentujących klasy Q0, Q1 i Q2 fenomenologicznych uniwersaliów. Uogólnione podejście CDG umożliwia również wygenerowanie lokalnych i nielokalnych stanów koherentnych oscylatorów, które minimalizują zasadę nieoznaczoności Heisenberga: położenie-pęd i czas-energia. Analiza otrzymanych wyników dowodzi [2,3], że przejście od rozwiązań kwantowych Qn do klasycznych Un dla n=1,2 zachodzi dla stanu dysocjacji oscylatora. Wtedy funkcje kwantowe przechodzą w klasyczne, otrzymane w podejściu CDG, co uzasadnia nadaną im nazwę – rozwiązania quasi-kwantowe. Należą do nich wszystkie najważniejsze czasowo-zależne modele opisujące ewolucję układów biologicznych oraz przestrzenno-zależne funkcje opisujące skumulowaną dystrybucję obiektów, różniących się rozmiarem (np. średnicą aksonów w włóknie nerwowym).
[1] P. Castorina, P. P. Delsanto, C. Guiot, Physical Review Letters 96 (2006) 188701.
[2] M. Molski, Physics Letters A 381 (2017) 2629–2635.
[3] M. Molski, Physics Letters A 382 (2018) 79–84.

Streszczenie: W ramach seminarium zostaną omówione wybrane metody modelowania pracy akumulatorów oraz superkondensatorów w stanach dynamicznych, a także metody estymacji parametrów modelu. Poruszona zostanie krótko problematyka energochłonności pojazdów oraz metody doboru akumulatorów do zasięgu i dynamiki jazdy. W referacie zaprezentowane zostaną również przykładowe wyniki badań energochłonności pojazdu, analizy pracy akumulatorów oraz metody wydłużenia żywotności akumulatorów z wykorzystaniem rozwiązań hybrydowych.

Abstract: The impressive development of experimental techniques in ultracold quantum degenerate gases of alkaline-earth-like atoms in the last years has allowed investigation of strongly correlated systems. Long-lived metastable electronic states in combination with decoupled nuclear spin give the opportunity to study the Hamiltonians beyond the possibilities of current alkali-based experiments. Ytterbium is particularly convenient due to its large number of bosonic and fermionic (e.g. Yb-173) isotopes with a wide range of interaction strengths. In [1] we study finite-temperature properties of ultracold four-component mixtures of alkaline-earth-metal-like atoms in optical lattices that can be effectively described by the two-band spin-1/2 Hubbard model including Hund’s exchange coupling term. Our main goal is to investigate the effect of exchange interactions on finite-temperature magnetic phases for a wide range of lattice fillings. We use the dynamical mean-field theory approach and its real-space generalization to obtain finite-temperature phase diagrams including transitions to magnetically ordered phases. It allows to determine optimal experimental regimes for approaching long-range ferromagnetic ordering in ultracold gases. We also calculate the entropy in the vicinity of magnetically ordered phases, which provides quantitative predictions for ongoing and future experiments aiming at approaching and studying long-range ordered states in optical lattices. In [2] we study the thermodynamic properties of four-component fermionic mixtures described by the Hubbard model using the dynamical mean-field-theory approach. Special attention is given to the system with SU(4)-symmetric interactions at half filling, where we analyze equilibrium many-body phases and their coexistence regions at nonzero temperature for the case of simple cubic lattice geometry. We also determine the evolution of observables in low-temperature phases while lowering the symmetry of the Hamiltonian towards the two-band Hubbard model. This is achieved by varying interflavor interactions or by introducing the spin-flip term (Hund’s coupling). By calculating the entropy for different symmetries of the model, we determine the optimal regimes for approaching the studied phases in experiments with ultracold alkali and alkaline-earth-like atoms in optical lattices.

[1] A. Cichy, A. Sotnikov, Phys. Rev. A 93, 053624 (2016)
[2] A. Golubeva, A. Sotnikov, A. Cichy, J. Kuneš, W. Hofstetter, Phys. Rev. B 95, 125108 (2017)

Abstract: [PDF]  Significant progress in polymerization techniques allows to synthesize macromolecules with complex, yet precisely controlled structure. Three distinct examples are branched bottlebrushes, star polymers and ring-like polymers. During the talk I will demonstrate that variation of macromolecular architecture affects structural, mechanical, interfacial and frictional properties of polymers as compared to conventional linear chains.

Abstract: Negative probability was introduced by Feynman to address a mystery of quantum theory [1]. Since then there have been many studies based on such approach. But from the point of view of the operationalism, there are conceptual problems of interpreting such probability with respect to a given physical situation. In other words, the meaning of the negative values is not clear. Recently, an operational quasiprobabilities (OQs) are introduced for qudits as well as optical fields states [2,3]. Here, we will discuss how the OQs deal with those problems.
[1] R. Feynman, in Negative Probabilities in Quantum Mechanics, edited by B. Hiley and F. Peat (Routledge, London, 1987).
[2] J. Ryu, J. Lim, S. Hong, and J. Lee, Operational quasiprobabilities for qudit, Phys. Rev. A 88, 052123 (2013).
[2] J. Jae, J. Ryu, and J. Lee, Operational quasiprobabilities for continuous variables, Phys. Rev. A 96, 042121 (2017).

Abstract: Having seen the possibility of controlling multi-body quantum systems indirectly, as well as that of identifying the entire Hamiltonian, now let us consider a more fundamental/abstract problem. When our direct access, or the number of (direct) control probes, to the system is limited, what is the extent to which it can be identified/controlled? This is a natural question, especially after realising that there are (infinitely) many systems that cannot be distinguished via restricted access. In our attempt to understand the intrinsic origin of the indistinguishability, we have revealed the characteristic structures of Hilbert space that is induced by the limited access. The structure tells us what draws the line between controllable and uncontrollable subsystems, which necessarily leads to indistinguishability as well.

Abstract: The machine learning functionality has been significantly augmented in Mathematica 11. There are a number of functions that allow us to start machine learning quickly without expertise in this field. At the same time, it provides us with a rich set of components to build up more complex tools, such as deep neural networks. I will show how Mathematica can be used to carry out machine learning computations for various types of data sets.

Abstract: Towards the full manipulation of multi-body quantum systems, there are still a number of obstacles we have to overcome. We would need some tricks when taming a complex quantum system, contemplating what we can do and what we cannot. In this talk, I will delineate a theoretical guiding principle for quantum controllability, and will present a specific idea for controlling a spin system with a highly limited access. Three important issues, i.e., the controllability, the computability of pulse sequence, and the time-scale of quantum computing operations, are addressed and answered positively.

Abstract: The study deals with modelling electronic and transport properties of unstrained and uniaxially deformed graphene with structural imperfections: zero-dimensional (point) and one-dimensional (extended) defects. Point defects are modelled as resonant (neutral) adsorbed atoms or molecules, vacancies, charged impurities, and local distortions. Extended (line) defects are attributed to atomic steps and terraces in epitaxially-grown graphene, and grain boundaries, quasi-periodic nanoripples or wrinkles in polycrystalline (chemically vapor-deposited) graphene. Results are obtained numerically using the quantum-mechanical Kubo-Greenwood formalism along with tight-binding approach. Calculated behaviours of electronic density of states and conductivity indicate that deviations from perfection can be useful: they make possible tailoring graphene’s electrotransport properties for achievement of new functionalities.

Abstract: [PDF]  DNA damage is a well-recognised causal factor of gene dysfunction in cancers and age-related diseases. Because DNA of all living cells is constantly exposed to a variety of reactive endogenous metabolites and environmental toxicants, DNA damage can never be fully avoided and its complexity comprises dozens of structurally different DNA modifications (“DNA lesions”). Knowledge of the lesion-specific responses of cells is required to characterise hazards of exposure to specific genotoxic agents and, from the translational perspective, to identify molecular susceptibility markers and potential targets for personalised therapeutic interventions.
My team exploits synthetic nucleotide derivatives to understand harmful consequences of individual DNA lesions and the lesion-specific repair mechanisms. To model damage induced by food carcinogens, drugs, environmental toxicants and endogenous cellular mechanisms at specific nucleotide positions, we incorporate synthetic analogs of the respective DNA modifications as building blocks into functional reporter genes [1-2]. Delivered to human host cells, such gene constructs can be efficiently used to monitor functional consequences of defined DNA lesions (tolerance versus toxicity), to characterise determinants of damage recognition by individual repair pathways, and to identify redundancy and potential switch points between the pathways [3-7]. I will discuss some recent applications of vectors containing the elements of synthetic nucleic acids to address questions in the fields of DNA repair and epigenetics.
 
[1] Lühnsdorf B, et al. (2012) Analytical Biochemistry 425: 47-53
[2] Kitsera N, et al. (2011) Nucleic Acids Research 39: 5926-5934
[3] Kitsera N, et al. (2014) PloS One 9: e94405
[4] Allgayer J, et al. (2013) Nucleic Acids Research 41: 8559-8571
[5] Lühnsdorf B, Epe B, Khobta A (2014) The Journal of Biological Chemistry 289: 22008-22018
[6] Allgayer J, et al. (2016) Nucleic Acids Research 44: 7267-7280
[7] Kitsera N, et al. (2017) Nucleic Acids Research doi: 10.1093/nar/gkx718 [Epub ahead of print].

Abstract: [PDF]  Every single day an individual cell must deal with ~10,000 lesions in order to prevent accumulation of harmful mutations, which might lead to cancer. Understanding the mechanism of DNA repair is therefore of central importance to our understanding of cancer and for the development of new therapeutics against it. Repair pathways are highly conserved, in both prokaryotes and eukaryotes, and studying the simpler pathways in bacteria provides key insight into the mechanism used by human cells to repair damaged DNA. We apply an interdisciplinary approach to understand the mechanistic details of DNA repair pathways (Nucleotide Excision Repair, Mismatch Repair, Base Excision Repair) in living Escherichia coli (and human cells in near future). We use a combination of cutting-edge single-molecule methods to elucidate how repair enzymes participate in removal of damaged nucleotides. Firstly, live super-resolution microscopy combined with single-particle tracking is used to study the behaviour of individual proteins as they scan the genome and repair damaged DNA. To complement this, we use cell biology, genetics and TIRF microscopy to verify and extend the conclusions established using a super-resolution microscopy. Together, this will provide a comprehensive understanding of the bacterial repair pathway, and constitute a starting point to understanding the way mutations in human repair proteins contribute to the development of cancer.

Streszczenie: Na seminarium omówione zostaną wyniki badań opublikowane w ostatnim numerze Nature 550, 219 (2017)  w artykule pt. The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation.

Abstract: In the year 2015, Svozilík and co-authors published a paper [Phys. Rev. Lett. 115, 220501 (2015)] discussing migration of coherence of the studied system between its subsystems. The authors showed that the coherence is also linked to the correlations between the subsystems. The authors mentioned a few interesting examples, where it is possible to study conservation of the maximal accessible coherence in the system. We want to demonstrate the effect of migration of coherence of the system on two experimental schemes implemented using polarization states of photons. The first scheme is based on linear optical controlled-phase quantum gate and the second scheme is utilizing effects of nonlinear optics.

Abstract: The talk discusses our experimental implementation of a linear-optical quantum router. This device allows single-photon polarization-encoded qubits to be routed coherently into two output modes. Routing is programmed by two identical control qubits and over this procedure, the quantum information stored in the state of the routed photon is not disturbed. The success probability of our scheme can be increased up to 25% making it the most efficient linear-optical quantum router known to this date.

Abstract: We develop a simple model describing inherent photon-number noise in Rarity-Tapster-Loudon-type interferometers. This noise is caused by generating photon pairs in the process of spontaneous parametric down-conversion and adding a third photon by attenuating the fundamental laser mode to the single-photon level. We experimentally verify our model and present resulting signal-to-noise ratios as well as obtained three-photon generation rates as functions of various setup parameters.

Abstract: [PDF]  Clay and colloidal particles of nano- and micrometer size adsorb strongly at liquid interfaces where they display a wide range of studies and applications [1],[2], for instance to stabilize emulsions, in material development and to encapsulate, store and release a range of materials such as medicine, cells, food or oil. Structuring of particles on droplets is a particularly hot topic these days with increasing interest and efforts devoted to the synthesis of functional colloidal capsules. Such capsules, with tailored physical, chemical or morphological characteristics, can be used as building blocks to prepare complex structures with advanced and novel material properties [3]. The talk will demonstrate and explain how weakly conductive (leaky-dielectric) droplets behave when suspended in another weakly conducive fluid and subjected to an external electric field. Especially how electrohydrodynamic and eletrorheological effects in such droplets can be used to structure and dynamically control colloidal particle assemblies at droplet surfaces. This includes electric-field-assisted convective assembly of jammed colloidal “ribbons”, electrorheological colloidal chains confined to a two-dimensional surface and spinning colloidal domains. In addition, the talk will demonstrate the size control of “pupil” like openings in colloidal shells [4], present a simple and robust method to assemble colloidal shells of controlled heterogeneity [5] and discuss some of the many applications for particle covered droplets.
[1] B. P. Binks, Curr. Opin. Colloid In. 7, 21 (2002).
[2] C. Zeng, H. Bissig, and A. D. Dinsmore, Solid State Commun. 139, 547 (2006).
[3] B Bollhorst, T., K. Rezwan, and M. Maas, Chemical Society Reviews, 46, 2091 (2017).
[4] P. Dommersnes, Z. Rozynek, A. Mikkelsen, R. Castberg, K. Kjerstad, K. Hersvik, and J. O. Fossum, Nat. Commun. 4, 2066 (2013).
[5] Z. Rozynek, A. Mikkelsen, P. Dommersnes, and J. O. Fossum, Nat.Commun. 5, 3945 (2014).

Abstract: [PDF]  The fabrication of 1D granular and colloidal materials is of considerable interest as they offer opportunities for a variety of electronic applications, including granular conductors, flexible electronics for wearable devices, electromagnetic energy transport, etc. These particle structures can be assembled either from particle groups or from individual particles. In this talk I will show structures composed of individual microparticles. There are several methods for fabricating particle structures, including lithography, cluster-assisted assembly and colloidal polymerization, pore-assisted assembly, and field-directed assembly in electro- or magneto-rheological fluids. The latter is generally considered to be a simple and effective approach to form particle structures. Thou fast and efficient, the external field-driven approach suffers from three major limitations to its applications, for example in electronic-device manufacturing. First, the assembly often takes place in a bulk liquid; it is difficult to remove the bulk liquid and maintain the assembled structure intact. Second, in principal only linear 1D structures can be formed along the field lines and positioning of the formed structure is greatly limited. Third, maintaining the formed structures normally requires a continuous energy supply; once the external field is turned off, the structures disintegrate. Within this talk, I will present novel routes to overcoming these limitations, making it possible to easily fabricate self-sustained 1D structures outside of a dispersion. For more details, see the following article: Formation of printable granular and colloidal chains through capillary effects and dielectrophoresis, Nature Communications 2017, 8, 15255 

Abstract: [PDF]  The presentation will be devoted to novel functional nanomaterials precisely tailored for specific applications. The materials are based on porous silica matrices both in the form of powder and vertically aligned thin films. Powdered SBA-15 silica activated by copper ions can play a role of strongly antimicrobial specimen with restricted migration into environment. Thin film form of silica matrices with vertically aligned channels makes the materials highly applicative in electronics or IT technologies. We consider three types of such silica-templated materials for application as antimicrobial specimen or electronics elements. Porous silica films containing permanent magnetic specimen inside pores can be used for fabrication of super-dense magnetic memory. When silica is activated by individual molecular magnets in pores bottom the material can play a role of layout of molecular neurons. Porous silica thin layer containing strongly dipolar units have strong non-linear optical (NLO) response, that can be tuned by means of functional groups concentration variation.

Abstract: [PDF]  Chromosomes were first observed and the process of their segregation in mitosis described by Walther Flemming, working in Kiel, Germany, in 1878, but it was another 25 years before their role in inheritance was proposed. The coordinated processes of chromosome replication, unlinking and subsequent chromosome segregation underlie the life process. Defects in these processes lead to genetic diseases and a multitude of pathologies in humans, while interfering with these processes is the basis of the action of many antibiotics and anti-cancer agents.
My laboratory studies the molecular mechanisms of the action of the molecular machines that act in these processes in the bacterium E. coli by using a combination of in vivo and in vitro biochemistry, quantitative single-molecule imaging and genetics. The presentation will focus on the importance of eliminating ensemble averaging wherever possible and in the challenges of reconciling in vitro and in vivo experimental data and in building them into a mechanistic framework.

Abstract: One of the original motivations for quantum information theory was the use of quantum effects to protect the privacy of classical communications. Yet the new theory, which has grown to elegantly encompass all of classical informatics, has undermined the very notion of classical private information, by showing that it sits on a slippery slope between quantum information and public information. Classical privacy survives only as a useful approximation, since in principle any memory so well shielded that it can hold classical data without the environment finding out can also hold superpositions of the classical values, thereby serving as a quantum memory. To recover a sharp notion of classical privacy it suffices to consider scenarios in which some information escapes to a place beyond the reach of one’s adversaries.

Biography: Prof. Bennett is one of the most acclaimed physicists and one of the founding fathers of modern quantum information theory. Among his many discoveries are: reversible computation, explanation of Maxwell’s demon paradox, quantum cryptography, and quantum teleportation. He also created the foundations of entanglement theory and quantum communication. Prof. Bennett is a laureate of many awards including this year’s Dirac Medal. See Wikipedia  for more details.

Abstract: Nanomateriały cieszą się coraz większą popularnością w różnych dziedzinach życia, również w medycynie. Na przykład nanocząstki magnetyczne stosuje się w obrazowaniu MRI czy w hipertermii. Szczególnie obiecujące jest ich wykorzystanie jako nośniki leków w terapiach celowanych. Dzięki właściwościom magnetycznym nanocząstek, stosując odpowiednie sekwencje pól magnetycznych, można kontrolować ich ruch. Funkcjonalizowane nanocząstki mogłyby dostarczać lek bezpośrednio do miejsca choroby (stan zapalny, guz) omijając tkanki zdrowe. Wspomniane wcześniej właściwości magnetyczne nanocząstek można badać metodą elektronowego rezonansu spinowego (ESR). Otrzymuje się w ten sposób wiele cennych informacji zarówno o rdzeniu magnetycznym nanocząstki jak i jej powierzchni. Właściwości nanocząstek zależą od wielu czynników takich jak pokrycie, dołączony materiał, środowisko czy warunki zewnętrzne, w których się znajdują. Wszystkie te zależności można badać metodą ESR. Stosując tę metodę można również kontrolować jakość nanocząstek oraz śledzić ich starzenie i agregację. Szczególne znaczenie pod kątem zastosowania nanocząstek w terapiach celowanych ma zastosowanie ESR do monitorowania dyfuzji nanocząstek wymuszonej obecnością pola magnetycznego.

Abstract: Computational materials discovery is a new field of science, and an ongoing scientific revolution. New methods have for the first time enable systematic discovery of superior materials on the computer – instead of the traditional laboratory-based trial-and-error approach. This approach allows scientists to predict and investigate new materials, new phenomena in various dimensionalities, starting from the bulk and moving towards the 2D materials, 1D materials and molecules, clusters. Here the recent research on the computational search for new functional materials will be discussed. Among the 2D materials, particular attention is drawn to such films of atomic thickness as graphene, its derivatives. In addition, many of non-carbon materials, which has no layered counterparts in bulk, are found to be layered graphitic-like in nanoscale. Such evidences related to silicon carbide, zinc oxide and aluminum nitride. In the field of bulk materials (single crystals, composites, etc.), the main direction of theoretical material science is search for crystal structure with optimal desired properties, such as hardness, band gap, dielectric constant, etc. Using the evolutionary algorithm implemented in the software package USPEX, it became possible to predict stable compounds, their crystal structure using only data on their chemical composition. In addition, we studied the surface reconstruction of rutile-like RuO2, especially the most stable (110) surface, which is highly important for catalysis, sensing and charge storage applications.

Abstract: The results of experimental study of fundamental features of magnetically controlled metamaterials at microwave band are under discussion. Among them are: (1) the transformation of right-handed medium into left-handed medium and electrodynamic analogs of Tamm states; (2) the left-handed properties (controlled negative refraction) of semiconductor–ferrite composites; (3) formation of backward wave in the chiral magnetoactive medium; and (4) photonic crystals and magnetophotonic crystals. The possible technological implementations of metamaterials are described. Besides the special experimental equipment, designed for study both magnetic microwave metamaterials and electron spin/magnetic resonance in nanocomposites both at room and very low temperatures (0.3-300 K) are presented. Also the results of Electron Spin Resonance experimental research of spin dynamics in magnetic nanodots and nanostrips ensembles at T = 4.2-300K are discussed.

Abstract: With recent experiments on several particles confined in a one-dimensional optical traps quantum engineering has entered a completely new, so far unexplored, area of strongly correlated quantum systems. Apart from a few exceptions, it has commonly been assumed that particles of different kinds have the same mass and the main impact on properties of the system comes from an imbalance of the number of particles. In contrast, in my talk I will focus on the system of a few ultra-cold fermions of different masses. I will show that the mass difference between different fermionic components leads to the specific spatial fragmentation in one of the components. Although the mechanism predicted is universal with respect to the number of particles, the fragmentation occurs, depending on the shape of the confinement, for either the lighter or the heavier component. In consequence, the system may undergo a kind of critical transition that is induced by an adiabatic change of the external potential.

Abstract: I will summarize what we have learned about dusty galaxies at large distances from Earth. The characterization of their properties is crucial to understand the evolution of the Universe, because dust absorbed and re-emitted in the infrared 50% of stellar emission ever produced in the Universe. First, I will show my effort in obtaining the largest so far ( 2000 objects) sample of galaxies selected by their infrared emission. I will discuss their redshifts, stelar masses and star formation rates. These properties provide important tests of cosmological models. Then I will show how we can learn in what way the large masses of dust in the distant Universe were produced: either by asymptotic giant branch stars, by supernovae, or by dust grain growth in the interstellar medium. The knowledge of how early galaxies could produce their dust is important from the point of view of further evolution, because dust is enabling formation of molecular gas, the fuel for star formation.

Streszczenie: Ocena zrozumiałości mowy jest nie tylko narzędziem diagnostycznym wykorzystywanym w protetyce słuchu, ale może dostarczyć wielu istotnych informacji na temat funkcjonowania układu słuchowego człowieka, a także może być wykorzystana w badaniach innych procesów w centralnym układzie słuchowym. Co więcej, metody oceny zrozumiałości mowy posłużyć mogą także do analizy funkcjonowania układów fizycznych począwszy od aparatów słuchowych poprzez pomieszczenia, na różnego typu algorytmach przetwarzania sygnałów skończywszy.

Przedstawione do oceny publikacje wskazują na uniwersalność badań wykorzystujących zrozumiałość mowy w ocenie funkcjonowania zarówno układu słuchowego, jak i centralnego układu nerwowego. Co więcej prace te potwierdzają istotność, a wręcz konieczność wykorzystywania testów zrozumiałości mowy do oceny innych układów, w których ta zrozumiałość gra istotną rolę, jak np. algorytmy separujące sygnały, czy pętle indukcyjne wykorzystywane do poprawy zrozumiałości mowy u użytkowników aparatów słuchowych. Testy te posłużyć mogą także do weryfikacji obiektywnych parametrów służących jako predyktory zrozumiałości mowy (np. Speech Transmission Index, STI) lub jej poprawy (np. poprawa stosunku sygnału do szumu, SNR). Warto podkreślić, że wyniki prac otrzymano stosując najnowsze i najdokładniejsze metody pomiaru zrozumiałości mowy wnosząc tym samym nowe dane zarówno pod względem jakościowym, jak i pod względem obszarów badawczych.

Abstract: Focused electron beam induced deposition (FEBID) is a direct-write approach for the fabrication of 2D and 3D nanostructures in various materials research areas. These comprise superconductors, magnetic materials, multilayer structures, and various sensor applications. FEBID is based on the decomposition of organo-metallic precursor gas molecules which are injected into the chamber of a scanning electron microscope. The deposition of the material takes place at those points where the electron beam dwells for a longer time in accordance with a pre-defined pattern. A post-growth processing of FEBID structures allows one to modify their compositional, structural and magnetic properties. In this talk, a general introduction to the basics of FEBID will be given, with an outline of available FEBID materials. A particular focus will be on Co-based FEBID nanostructures and tuning their magnetic properties on the lateral mesoscale by an area-selective post-growth processing. Further, exemplary 3D FEBID nanostructures will be presented and the perspectives of their use in fluxonic, photonic, and magnonic metamaterials will be outlined.

Abstract: [PDF]  Low temperature (high-resolution) hole-burning (HB) spectroscopy and modeling studies of various optical spectra of photosynthetic complexes provide new insight into excited state electronic structure and dynamics. The following complexes will be briefly discussed: 1) The CsmA– bacteriochlorophyll α complex from C. tepidum. In this case, in contrast to literature data, an alternative structure is proposed for the baseplate; 2) The FMO antenna complex from C. tepidum and its mutants. Using an experimentally determined shape for the spectral density for the lowest- energy state (J_ph(ω)), simulated optical spectra are obtained from structure-based calculations for the FMO trimer. For higher energy pigments, the effect of a broader J_ph(ω) shape with a different S factor and/or variable Γ_inh are also tested for comparison. I will demonstrate that in order to properly describe various low-temperature optical spectra, a downward uncorrelated excitation energy transfer (EET) between trimer subunits must to be taken into account. That is, after light induced coherences vanish within each monomer, uncorrelated EET between the lowest exciton levels of each monomer takes place due to static structural inhomogeneities in the trimer. The information gained provides new insight into disorder, excitonic structure, EET dynamics and mutation induced changes induced via site directed mutagenesis; and 3) The B800-850 LH2 antenna complex from Alc.vinosum, which exhibits an unusual spectral splitting of the B800 absorption band. Here, we propose that various protein conformations lead to either strong or weak hydrogen bonds between the protein and B800 pigments.

Biography: Ryszard Jankowiak is a Distinguished Professor of Chemistry and Ancillary Distinguished Professor of Physics at Kansas State University, Manhattan, KS, USA. He is also affiliated with the Photosynthetic Antenna Research Center, Washington University, Saint Louis, MO. He has published over 230 papers in various areas of physical chemistry, toxicology, chemical carcinogenesis, physics, and biophysics. Currently he studies photosynthetic reaction centers and various antenna pigment complexes (including mutants) of green plants/algae and photosynthetic bacteria using solid-state low-temperature (laser-based) spectroscopies and theoretical modeling. Research Gate score: 43.2; over 5,340 citations. H INDEX 39. Contact phone numbers: +(785) 532- 6785 or +(785) 410-4163.

Abstract: Today’s magnetic device technology is based on complex magnetic alloys or multilayers that are patterned at the nanoscale and operate at gigahertz frequencies. To better understand the behavior of such devices one needs an experimental approach that is capable of detecting magnetization with nanometer and picosecond sensitivity. In addition, since devices contain different magnetic elements, a technique is needed that provides element-specific information about not only ferromagnetic but antiferromagnetic materials as well. Synchrotron based X-ray microscopy provides exactly these capabilities because a synchrotron produces tunable and fully polarized X-rays with energies between several tens of electron volts up to tens of kiloelectron volts. The interaction of tunable X-rays with matter is element-specific, allowing us to separately address different elements in a device. The polarization dependence or dichroism of the X-ray interaction provides a path to measure a ferromagnetic moment and its orientation or determine the orientation of the spin axis in an antiferromagnet. The wavelength of X-rays is on the order of nanometers, which enables microscopy with nanometer spatial resolution. And finally, a synchrotron is a pulsed X-ray source, with a pulse length of tens of picoseconds, which enables us to study magnetization dynamics with a time resolution given by the X-ray pulse length in a pump-probe fashion. The goal of this talk is to present an introduction to the field and explain the capabilities of synchrotron based X-ray microscopy, which is becoming a tool available at every synchrotron, to a diverse audience. The general introduction will be followed by a set of examples, depending on the audience, that may include properties of magnetic materials in rocks and meteorites, magnetic inclusions in magnetic oxides, interfacial magnetism in magnetic multilayers, and dynamics of nanostructured devices due to field and current pulses and microwave excitations.

Abstract: Spontaneous self-assembly of block copolymer (BCP) molecules in a block-selective solvent typically results in the formation of micelles possessing a classical spherical morphology. Inclusion of a crystallizable block in the copolymer promotes crystallization-driven self-assembly (CDSA), yielding anisotropic cylindrical micelles that can, after additional processing, possess a remarkably narrow length polydispersity. Anisotropic nanoparticles prepared from BCPs are of growing importance as building blocks for the creation of a wide range of synthetic hierarchical materials. However, the assembly of such structural units is generally limited to the use of amphiphilic interactions. In addition to CDSA to generate single cylindrical micelles, reversible coordination-driven hierarchical self-assembly can be used to produce micron-scale fibers and macroscopic films based on the association of low-polydispersity cylindrical BCP micelles. In this case, coordination of palladium metal centers to phosphine ligands immobilized within the soluble coronas of BCP micelles is observed to induce intermicellar crosslinking, affording stable linear fibers comprised of micelle subunits in a staggered arrangement. The mean length of the fibers can be readily varied by altering the micelle concentration, reaction stoichiometry or aspect ratio of the micelle building blocks. Furthermore, the fibers aggregate upon drying to form robust, self-supporting macroscopic micelle-based thin films with useful mechanical properties that are analogous to crosslinked polymer networks, but on a significantly longer length scale. A comparable hierarchical self-assembly strategy yields toroidal micelles that combine to form micron-scale superstructures. Addition of a crystallizable BCP to a solution of a toroid-forming BCP results in the formation of toroidal multimicelles, as well as single-layer hexagonal arrays of connected toroids. By controlling the ability of the BCPs to form hydrogen bonds through the introduction of hydroxyl groups on the crystallizable BCP and the accompanying level of solvophobic interactions, the BCPs can spontaneously self-assemble to form 3D periodic mesoporous superstructures. Studies such as these demonstrate that self-assembly of BCPs into discrete, non-spherical nanostructures can be scaled from the “ground-up” to yield materials with intriguing morphologies and potentially unique properties.

Streszczenie: Pojęcie odwrotności Moore’a-Penrose’a macierzy odgrywa ważną rolę w rozmaitych dziedzinach nauki. Bodajże najlepiej znany przykład jego zastosowania dotyczy metody najmniejszych kwadratów wykorzystywanej w większości obszarów badań naukowych odwołujących się do metod matematycznych. Jednak przykłady zastosowań odwrotności Moore’a-Penrose’a obejmują także inne zagadnienia, z których wiele wywodzi się z fizyki. W trakcie seminarium przedstawione zostaną rezultaty odnoszące się do odwrotności Moore’a-Penrose’a rozmaitych funkcji macierzy ze szczególnym naciskiem położonym na alternatywne sposoby reprezentowania tego pojęcia. Wśród poruszonych zagadnień znajdą się m.in.: odwrotności Moore’a-Penrose’a macierzy zmodyfikowanej macierzą rzędu 1, odwrotność core (i jej związki z odwrotnościami Moore’a-Penrose’a, Botta-Duffina i grupową), a także unitarnie niezmiennicze miary rozseparowania przestrzeni wektorowych. W obrębie zainteresowania będą przy tym klasy macierzy hermitowskich, idempotentnych i EP.

Abstract: We test non-locality of a single-particle under feasible measurements, such as on-off and homodyne detections along with displacement and squeezing operations. On-off detection exhibits the existence of intensity of light by its click event, and homodyne detection shows the information on the phase of light by measuring intensity difference. We find that a single-particle entangled state can violate the CHSH inequality up to 2.782 when all four measurements are squeezed-and-displaced on-off detections.

Abstract: [PDF]  The term of computational chemistry may be defined as the mathematical description and numerical computation of molecular structures. The term computational chemistry is generally used when a mathematical method is sufficiently well developed that it can be automated for implementation on a computer. Computational chemistry has become a useful way to investigate materials that are too difficult to find or too expensive to purchase. It also helps chemists make predictions before running the actual experiments so that they can be better prepared for making observations. It’s also useful ways to explain of spectroscopic results of molecular structures. The mathematical description of the molecular structures based on the Quantum mechanics rules. Because of the Quantum mechanics (QM) is the correct mathematical description of the behaviour of electrons and thus of molecular structures. In theory, QM can predict any property of an individual atom or molecule exactly. In practice, the QM equations have only been solved exactly for one electron systems. A myriad collection of methods has been developed for approximating the solution for multiple electron systems. These approximations can be very useful, but this requires an amount of sophistication on the part of the researcher to know when each approximation is valid and how accurate the results are likely to be. In my presentation, I intend to give you some information about a few examples of our work entitled “Combined experimental–theoretical characterization of chelidamate nickel complex with 4-methylpyrimidine”. A new chelidamate complex of nickel (II) ion was synthesized and characterized by single-crystal X-ray diffraction, UV–Vis and FT-IR spectroscopy. Theoretical calculations have been carried out by using Hartree–Fock (HF)/6-31G (d) and Density Functional Theory (DFT)/6-31+G (d). HOMO–LUMO energies, absorption wavelengths and excitation energy were computed by time dependent DFT (TD-DFT) method with polarizable continuum model. The observed FT-IR vibrational frequencies are analysed and compared with theoretically predicted vibrational frequencies.

Streszczenie: Przedstawiono wyniki badania wysokorozdzielczą spektroskopią Brillouina dyspersji fal powierzchniowych w różnego typu kryształach fononicznych. Powierzchniowe własności sprężyste badanych próbek symulowano, w każdym przypadku, metodą elementów skończonych (FEM). Dla jednowymiarowych kryształów fononicznych pokazano wpływ periodyczności sieci na amplitudę fal powierzchniowych. W przypadku kryształów dwuwymiarowych zaobserwowano istnienie przerwy energetycznej a w strukturach wyspowych wykazano także istnienie modów „oddychających”. Ciekawe własności aplikacyjne obserwowano w przypadku zmodyfikowanej dwuwymiarowo struktury 1D.

Streszczenie: 11 lutego 2016 roku międzynarodowy zespół naukowców poinformował o pierwszym w historii zarejestrowaniu fal grawitacyjnych. Fale te zostały zarejestrowane w Stanach Zjednoczonych równocześnie przez dwa detektory LIGO (Laser Interferometer Gravitational-wave Observatory), oddalone od siebie o ponad 3 tys. kilometrów.

Podczas seminarium, w elementarny sposób omówimy różnice między teorią grawitacji Newtona a elektrodynamiką. Następnie przedstawimy w jaki sposób Einstein zmodyfikował teorię Newtona i omówimy podstawowe eksperymenty potwierdzające jego teorię grawitacji. Wyjaśnimy, dlaczego w teorii tej, podobnie jak w elektrodynamice, występują rozwiązania falowe. Na koniec omówimy wspomniany na początku eksperyment, w którym zaobserwowano fale grawitacyjne.

Streszczenie: Chromodynamika kwantowa (QCD) jest obowiązującą teorią oddziaływania silnego. W reżimie niskoenergetycznym stała sprzężenia QCD jest duża i nie jest możliwe zastosowanie rachunku zaburzeń. Jedynym podejściem dającym ilościowe przewidywania z pierwszych zasad jest sformułowanie QCD na Euklidesowej sieci czasoprzestrzennej oraz obliczenie odpowiednich całek po trajektoriach numerycznie, używając algorytmów Monte Carlo. Seminarium to poświęcone będzie wynikom uzyskanym przy użyciu jednej z najważniejszych dyskretyzacji działania fermionowego, tzw. twisted mass. Przedstawimy wnioski dotyczące nieperturbacyjnej renormalizacji, a także spektralnych, chiralnych i topologicznych własności QCD.

Abstract: Rapid and major advances in the field of ultracold gases in optical lattices as well as ultra-fast pump-probe spectroscopy in solids are allowing unprecedented control of strongly correlated quantum many body systems with light. In this talk we shall present two examples of such control. In the optical lattice setting, we describe a new system that can be implemented in current state-of-the-art experiments with two species of fermions and tuned to extreme parameter regimes. This system exhibits a combination of interesting features: hidden string order, hole superconducting correlations and non-trivial excitations. In the condensed matter settings, we outline a recent experiment demonstrating the switching of orbitally ordered domains in the prototypical manganite LSMO (La0.5Sr1.5MnO4) with non-resonant THz light and provide a simplified model description of the observed effect.

Abstract: [PDF]  In recent years the growing attention is paid to a broad interdisciplinary ‘bio-interface science’, on the border between physics and biology, focused at the design of novel, innovative coatings enabling to use polymer materials with the controlled physicochemical properties for biomedical applications. The biocompatibility of the material and possibility of its biomedical applications is determined by its interactions with biological material, dependent on physicochemical properties of the surface, such as chemical composition, wettability, topography or elasticity. In the lecture, the idea of controlling the physicochemical properties of the substrate in the way enabling controlled interactions between the polymer coatings and the biological material will be presented. The results of performed experiments regarding the impact of substrate elasticity on the behavior of cancerous cells at different stage of cancer progression as well as the design and complex characterization of thermoresponsive, intelligent polymer coatings with controlled physicochemical properties will be reported. Conducted studies cover numerous steps, including the design and fabrication of polymer coatings with controlled properties, their complex characterization, as well as biocompatibility tests for both, proteins and cells. The obtained results enable deeper understanding of the complex interactions on the bio-interface between the surface and biological material.

Streszczenie: W ostatnich latach jednym z głównych kierunków rozwoju nauk z pogranicza fizyki polimerów, biologii i medycyny jest poszukiwanie innowacyjnych rozwiązań pozwalających na wykorzystanie pokryć polimerowych o kontrolowanych właściwościach fizykochemicznych do zastosowań biomedycznych. O możliwościach aplikacyjnych podłoża decyduje jego zdolność do oddziaływania z materiałem biologicznym, determinowana przez właściwości powierzchni, takie jak skład chemiczny, zwilżalność, topografia czy elastyczność. W referacie zostanie przedstawione zagadnienie możliwości kontroli właściwości fizykochemicznych podłoża w celu uzyskania kontrolowanych oddziaływań pokryć polimerowych z białkami i komórkami. Opisane zostaną wyniki badań dotyczących wpływu elastyczności podłoża na zachowanie komórek nowotworowych o różnym stopniu zaawansowania oraz tworzenia i kompleksowej charakterystyki termoprzełączalnych inteligentnych pokryć polimerowych. Badania te obejmowały szereg etapów, poczynając od zaprojektowania i wytworzenie podłoży o zadanych właściwościach, poprzez kompleksową charakterystykę ich właściwości fizykochemicznych aż do testów biokompatybilności, prowadzonych zarówno dla białek, jak i dla komórek. Otrzymane wyniki pozwalają na głębsze Poznańie skomplikowanych oddziaływań zachodzących pomiędzy podłożem a materiałem biologicznym.

Abstract: Electric conductivity [1] and ferromagnetic Curie temperature of bulk Mn-doped Bi₂Se₃ and Bi₂Te₃ 3D topological insulators are systematically studied by means of atomistic Monte Carlo simulations. Exchange interactions between the Mn magnetic moments have been calculated using ab initio methods. Tight-binding linear muffin-tin orbital method has been employed, together with the coherent potential approximation to describe the high degree of disorder in the system. Spin-orbit interaction is included in the ground state calculation. In the studied materials Mn atoms might either replace a Bi atom (substitutional position) or fill an empty position in van Der Waals gap between the atomic layers (substitutional position). It has been shown that exchange interaction between Mn magnetic moments might lead to a ferromagnetic phase transition. The Curie temperature is shown to be significantly dependent on the concentration of Mn atoms in substitutional and interstitial positions. [1] K. Carva, J. Kudrnovský, F. Máca, V. Drchal, I. Turek, P. Baláž, V. Tkáč, V. Holý, V. Sechovský, J. Honolka, Phys. Rev. B 93, 214409 (2016).

Abstract: Quantum channels can be used to transfer both classical and quantum information. The capacity of a quantum channel is defined by the upper bound of it transmission rate. The capacity improvement of a quantum channel remains an open question. In this presentation, I will discuss a systematic method to investigate quantum channel capacity in spectral domain under stringent constrained resources, particularly photons, which is then apportioned under more realistic circumstances. Here, a classical signal analysis methodology is used to match the power spectral density of the signal to the spectrum of a squeezed channel supported by a subthreshold optical parametric oscillator. Furthermore, using water-filling algorithm, I will define and declare the first time, the upper bound of the channel capacity of a quantum channel under realistic practical assumptions. Following on from that, I will establish the best signal-to-noise ratio and bit-error-rate that can be achieved for a bipolar non-return to zero digital signals imposed on the squeezed output of a sub-threshold optical parametric oscillator, for given fixed number of photons in the channel. For a range of parameters, I will establish the circumstances under which the squeezed channel can perform better than a classical channel (as supported by a coherent state). Using these techniques, I will optimize the capacity of a quantum channel for a given photon flux in the channel. This also provides the machinery needed to design experiments that would demonstrate quantum enhancement. Further discussion, if one considers mismatched parameter regime, in fact very importantly show how by increasing squeezing level decreases quantum enhancement. I will also discuss how to use these ranges of optimum parameters to design a quantum channel.

Abstract: I will consider the problem of deciding if a finite set of quantum one-qudit gates is universal, i.e if the generated group is either the special unitary or the special orthogonal group. To every gate I will assign its image under the adjoint representation. The necessary condition for the universality is that the only matrices that commute with all the adjoint representation matrices are proportional to the identity. If in addition there is an element in the considered group whose Hilbert-Schmidt distance from the centre is smaller than 1/√2, then the set of gates is universal. Using these I will present a simple algorithm that allows deciding the universality of any set of d-dimensional gates in a finite number of steps. Moreover, I will formulate the general classification theorem. This is a joint work with Katarzyna Karnas.

Streszczenie: Prezentowana praca jest poświęcona analizie modelu błądzenia kwantowego wzbogaconego o możliwość definiowania różnych rodzai krawędzi. Poszczególne rodzaje krawędzi definiowane są poprzez zróżnicowanie zmiany fazy następującej podczas przejścia daną ścieżką. Prezentujemy metody pozwalające lokalnie badać własności sieci oparte na rodzajach występujących krawędzi oraz sterować zachowaniem błądzenia w zależności od tych własności. W szczególności rozważamy problem przeszukiwania w przypadku gdy rodzaj krawędzi określa czy dany kierunek może prowadzić do szukanego wierzchołka.

Streszczenie: Przewidziane blisko 100 lat, temu zjawisko rozpraszania Brillouina pozwoliło na połączenie dwóch wówczas niezależnych gałęzi fizyki: termodynamikę i optykę. Od tego czasu, systematyczny rozwój technik pomiarowych zamienił ciekawą koncepcję fizyczną w pełni rozwiniętą metodę spektroskopową wykorzystywaną w badaniach spontanicznych wzbudzeń akustycznych w materii skondensowanej.

Podczas wystąpienia przedstawiona zostanie droga jaką przebyła metoda spektroskopii Brillouina, zaczynając od wyjaśnienia fizycznych podstaw zjawiska, które doprowadziły do jego teoretycznego przewidzenia. Zaprezentowany zostanie rozwój w konstrukcji wysoko-rozdzielczych spektrometrów optycznych, począwszy od pierwszych układów użytych do doświadczalnego potwierdzenia zjawiska rozpraszania Brillouina, aż po współczesne instrumenty wykorzystywane w fizykochemicznych badaniach materii skondensowanej. Omówiona zostanie również najnowsza konstrukcja spektrometru brillouinowskiego, dzięki której możliwy stał się szybki, bezkontaktowy i bezinwazyjny pomiar właściwości mechanicznych materii miękkiej, znajdujący zastosowanie w zagadnieniach biomedycznych.

Abstract: Imagine a future in which food is used to activate specific immune reactions in a human body based on an external noninvasive magnetic stimulus. Dream of a material that stores and releases energy reversibly by temperature changes between day and night. These visions may be realized by using magnetic nanoparticles that are functionalized to be biocompatible, environmentally stable and recyclable, self-healing, and low-cost.

In this presentation I will discuss the basic concepts of magnetic nanomaterials and their magnetic properties with a focus on how to tune specific parameters in a controlled fashion to achieve the dreams of the future. I will highlight state-of-the-art experimental technologies that allow us to understand microscopic properties and interactions in relation to electronic structure changes caused by changes in size, shape, and composition of nanomaterials. Then I will discuss how this understanding is used when nanomagnets are functionalized for targeted drug delivery or composed to form macroscopic materials for new energetic applications like magnetic refrigeration. I will demonstrate that the seemingly complex behavior of hybrid metal/metal, metal/oxide, or oxide/oxide interface materials can be understood from the three fundamental interactions in magnetism: magnetic exchange interaction due to orbital overlap, spin-orbit interaction due to inner- and intra-atomic relativistic corrections (e.g., crystal field effects) and the long-range magnetic dipolar interaction. Several examples will be presented, including the formation of above-room-temperature ferromagnetic interface layers between low-temperature antiferromagnetic layers and the evolution of lattices of magnetic textures (skyrmions) in confined dimensions. The talk will end with an episode in the life of an imaginary golf-playing couple in the year 2040 who use their “Smart Magnet” (SMAG) phone to energize and heal their bodies on the green.

Biography: Michael Farle received his Diploma in experimental physics, Doctorate, and Habilitation degrees from Freie Universität Berlin in 1984, 1989, and 1998, respectively. During this time he spent three and a half years as a senior researcher at Stanford University, California, and Université de Strasbourg, France. In 1999, he moved to Technische Universität Braunschweig, Germany, where he became a full professor. Since 2002, he has been working as a professor at the Universität Duisburg-Essen, Germany, where he has served as Vice-Rector for Research and Junior Scientific Staff. In 2016 he became, in addition, an adjunct professor at Immanuel Kant Baltic Federal University, Kaliningrad, Russia. Prof. Farle has published over 220 technical articles in peer-reviewed journals, including book chapters and review articles, and has given more than 60 invited presentations. He coordinated two European Research Networks and served as the vice-spokesman of Collaborative Research Center: Magnetic Heterostructures (SFB 491). Since 2014 he is chairman of the Magnetism Section of the German Physical Society. For many years he has been active on the program committees of several international conferences on magnetism. He is a member of the IEEE Magnetics Society, the German Physical Society, and is a co-editor of Materials Research Letters and Journal of Magnetism and Magnetic Materials. source: [IEEE Magnetics Society about the 2017 Distinguished Lecturer] 

Streszczenie: Od roku 1950 kiedy to Jan H. Oort sformułował swoją hipotezę o sferycznym rezerwuarze komet otaczającym Układ Słoneczny trwają badania nad bliskimi przejściami gwiazdowymi. Oort sugerował, że takie zbliżenia są jedynym źródłem komet długookresowych (LPC’s) – dziś wiemy, że działają również inne mechanizmy. Jednak częstość występowania bliskich przejść gwiazdowych jest wciąż tematem dyskusji. Wynika to między innymi z faktu, że do niedawna badania gwiazd zbliżających się do Słońca w głównej mierze opierały się na danych zgromadzonych przez sondę Hipparcos w pierwszej połowie lat 90. ubiegłego wieku, na podstawie których powstał katalog zawierający wszystkie parametry astrometryczne dla około 120 000. We wrześniu ubiegłego roku został opublikowany pierwszy katalog oparty o dane zgromadzone przez sondę Gaia z pierwszych 14 miesięcy jej działania. Katalog ten zawiera niezbędne informacje dla ponad dwóch milionów gwiazd. Jednym z pierwszych wyników uzyskanych dzięki temu katalogowi jest udokładnienie parametrów przejścia gwiazdy Gliese 710, która po tej korekcie przejdzie nie 60 tys. AU od Słońca jak to wynikało z wcześniejszych badań a tylko około 13 tys. AU. Tak bliskie przejście gwiazdy spowoduje duże perturbacje w Obłoku Oort’a czego skutkiem może być nawet dziesięć nowych komet rocznie pochodzących z tej odległej części Układu Słonecznego.

Abstract: For numerous applications of quantum theory it is desirable to be able to apply arbitrary unitary operations on a given quantum system. However, in particular situations only a subset of unitary operations is easily accessible. This provokes the question of what additional unitary gates should be added to a given gate set in order to attain physical universality, i.e., to be able to perform arbitrary unitary transformation on the relevant Hilbert space. In this work, we study this problem for three paradigmatic cases of naturally occurring restricted gate sets: (A) particle-number preserving bosonic linear optics, (B) particle-number preserving fermionic linear optics, and (C) general (not necessarily particle-number preserving) fermionic linear optics. Tools from group theory and control theory allow to classify, in each of these scenarios, what sets of gates are generated, if an additional gate is added to the set of allowed transformations. This solves the universality problem completely for arbitrary number of particles and for arbitrary dimensions of the single-particle Hilbert space.
After the presentation of these results, I will show they can be useful in the context of quantum metrology [1] and for the model of quantum computation based on fermionic linear optics [2,3].
This talk is based on a joint project with Zoltan Zimboras (Freie Universitat Berlin).
[1] M. Oszmaniec, R. Augusiak, C. Gogolin, J. Kołodyński, A. Acín, and M. Lewenstein, Phys. Rev. X 6, 041044 (2016)
[2] Sergey Bravyi, Phys. Rev. A 73, 042313 (2006)
[3] Fernando de Melo, Piotr Ćwikliński, Barbara M. Terhal, New J. Phys. 15 013015 (2013)

Abstract: The development and fabrication of mechanical devices powered by artificial molecular machines is one of the contemporary goals of nanoscience. Before this goal can be realized, however, we must learn how to control the coupling/uncoupling to the environment of individual switchable molecules, and also how to integrate these bistable molecules into organized, hierarchical assemblies that can perform significant work on their immediate environment at nano-, micro- and macroscopic levels. In this lecture we review some ideas for which the Nobel Prize in Chemistry was awarded in 2016.

Abstract: A Kosterlitz-Thouless phase transition in the ground state of an antiferromagnetic spin-1/2 Heisenberg chain with nearest and next-nearest neighbor interactions is re-investigated from a new perspective: A mapping of the components of the scalar product onto loops is found. One can classify these loops according to whether any two of them can be transformed into each other in a continuous way (i.e., whether they have the same winding number). A finite size scaling of the fidelity susceptibility and geometrical phase calculated in the ground state of the considered system within each class of above mentioned loops leads to the critical value of coupling constant and critical exponents with high accuracy.

Abstract: Recently there has been enormous interest in studying the Majorana fermions (identical with their own antiparticles) that can emerge as the effective quasiparticles in topological superconductors. They are appealing for the basic science and their non-Abelian character makes them promising for a brand new Majorana spintronics. So far the most convincing evidence for such exotic Majorana quasiparticles has been provided by tunneling measurements using, the Rashba chains brought in a contact with the s-wave superconducting samples (such as Pb). Independent experiments by groups in Delft, Princeton, Basel and Berlin have clearly indicated enhancement of the zero-bias STM conductance. Further efforts for detecting the Majorana fermions rely on novel methods, e.g. selective equal-spin Andreev reflection (SESAR), Josephson spectroscopy, fractional quantum interference etc. I shall describe main theoretical concepts beyond the Majorana-type quasiparticles, which can be regarded as mutations of the Shiba states of spinfull impurities in bulk superconductors. Next, I will illustrate non-local nature of such quasiparticles, discuss their fractionality (in comparison to ordinary electrons) and prove that they are not completely immune to disorder (despite a wide-spread belief). I will also comment on novel projects, related to localization of Majorana quasiparticles on interfaces or quantum defects.

Abstract: All systems fluctuate and according to quantum physics fluctuations persist even if all sources of error have been eliminated. The fluctuations limit the sensitivity achieved by detectors for spectral resolution and hence they limit the accuracy to which measurements can be performed. Quantum physics imposes a limit on the fluctuations called the quantum limit of fluctuations. Fluctuations of all systems including light are subject to this limit, and it was long believed that this limit could not be suppressed. In the 1980s theoretical studies followed by experimental measurements showed that the quantum limit can be beaten using quantum technologies that employ quantum effects such as quantum interference, squeezing, and entanglement. In this talk I will review the efforts done by researchers in the field of quantum optics to search for methods to reduce or even completely suppress the undesirable effects resulting from the presence of quantum fluctuations. The talk is based on the content of a book, Z. Ficek and R. Tanaś, Quantum-Limit Spectroscopy, published by Springer in November 2016.

Abstract: Worldwide efforts are underway to create revolutionary and energy-efficient data storage technology such as magnetic random-access memory (MRAM). An understanding of spin dynamics in inhomogeneously magnetized systems is indispensable for further development of nanoscale magnetic memory. This lecture provides a clear picture of inhomogeneously magnetized systems, such as magnetic nanowires with domain walls and disks with magnetic vortices, and presents not only technological developments and key achievements but also the unsolved puzzles and challenges that stimulate researchers in the field. First, the basic concept of an inhomogeneously magnetized system is described by introducing a magnetic vortex structure in a magnetic disk. A magnetic domain wall in a magnetic nanowire is also provided as a typical example. The magnetic field-driven dynamics of these inhomogeneously magnetized systems are described to illustrate their uniqueness. Second, electric-current-induced dynamics of magnetic vortices and domain walls are described. One can flip the core magnetization in a magnetic vortex using electrical current excitation, and move a domain wall by current injection into a wire. The next part focuses on the applications of current-induced magnetization dynamics in devices. The basic operations of two kinds of magnetic memories—magnetic vortex core memory and magnetic domain wall memory—are demonstrated. The lecture describes not only the current understanding about inhomogeneously magnetized systems, but also unexpected features that have emerged. It concludes with prospects for future developments.

Biography: Teruo Ono received the B.S., M.S., and D.Sc. degrees from Kyoto University in 1991, 1993, and 1996, respectively. After a one year stay as a postdoctoral associate at Kyoto University, he moved to Keio University where he became an assistant professor. In 2000, he moved to Osaka University where he became a lecturer and an associate professor. Since 2004, he has been working at Kyoto University, where he is now a professor. He has published over 280 technical articles in peer-reviewed journals, including book chapters and review articles, and has given more than 90 invited presentations at international conferences. He served as conference co-chair of the 8th International Symposium on Metallic Multilayers (MML) in 2013, and on the program committees of various international conferences on magnetism and spintronics. He is a member of the IEEE Magnetics Society and is an editor of the Japanese Journal of Applied Physics. source: [www.ieeemagnetics.org] 

Abstract: W prognozach głównych trendów rozwoju technologicznego i cywilizacyjnego w XXI wieku przewiduje się, że azotek galu (GaN), który jest stosunkowo nowym półprzewodnikiem, może odegrać rolę porównywalną z tą, jaką odegrał krzem w drugiej połowie XX wieku i bez którego trudno by było wyobrazić sobie obecnie funkcjonowanie świata. Nagroda Nobla z fizyki w 2014 r. dla I. Akasaki, H. Amano i S. Nakamury za skonstruowanie z GaN wydajnej diody emitującej światło niebieskie (blue LED) potwierdza trafność tych trendów. Wynalazek Noblistów pozwolił na dramatyczne zwiększenie efektywności zamiany energii elektrycznej na światło, co według szacunków amerykańskiego Departamentu Energii już w 2030 doprowadzi do zmniejszenia zużycia energii na oświetlenie w USA prawie o połowę. Na świecie badania azotku galu rozwijają się niezwykle dynamicznie i wiadomo już, że rewolucja w oświetleniu spowodowana wynalazkiem Noblistów jest dopiero początkiem przyszłych zastosowań tego półprzewodnika. Dlaczego jednak sukces tego półprzewodnika przyszedł tak późno? Które z jego własności o tym zadecydowały? Czy jest podobny do innych półprzewodników A^IIIB^V, czy też jest w nim jakaś tajemnica, która przez ponad 40 lat była barierą w praktycznym jego wykorzystaniu? Jakie to były bariery i jak zostały przełamane? W Polsce badania w tych dziedzinach rozwijają się bardzo intensywnie. Badania naukowe w zakresie fizyki i technologii tego stosunkowo nowego półprzewodnika są już obecnie prowadzone w 11 instytucjach naukowych. Powstały dwie firmy Ammono S. A. i TopGaN Sp. z o.o. prowadzące produkcję doświadczalną monokrystalicznych podłoży GaN oraz laserów niebieskich. Polska należy do elitarnej grupy krajów posiadających kompletną technologię produkcji niebieskich laserów (Japonia, Niemcy, USA, Polska). W prezentacji omówione zostaną niektóre wyniki polskich badań w dziedzinie w dziedzinie GaN oraz szanse na ich praktyczne wykorzystanie.

Abstract: Recently, there has been growing interest in the fabrication, characterization, and modeling of patterned magnetic thin films due to their potential applications in the field of magnetic storage, sensors, radio frequency components, information processing, and magnonic crystals. This specific interest is primarily due to the possibility of controlling the magnetic properties by introducing in ferromagnetic material artificial defects such as antidots, dots or nonmagnetic inclusions arranged in ordered or disordered arrays. In particular, the hysteresis properties of such systems can be easily tailored by shape, size, and distance between the nanostructures as well as by arrays order and their symmetry. The talk will focus on the magnetic properties and switching behavior of well-ordered magnetic antidot and dot arrays consisting of Co/Pd thin films. The patterning effect as well as the influence of period and size on domain shape and domain wall behaviour will be discussed. Magnetic transition from antidot to dot regime will be also analysed.

Abstract: Control of material properties is one of the driving forces in ultrafast optical sciences. The notion that light can influence intrinsic material parameters is founded on a wide range of experiments demonstrating optomagnetic control, light induced superconductivity, and the photo induced insulator to metal transition in a wide range of materials. A recent addition to the tool chest of control methodologies is the excitation of acoustic waves, and their affect on intrinsic materials properties; particularly the material magnetization via magnetostrictive effects. In this talk I will describe our recent efforts [1,2] to optically generate in-plane magnetoelastic waves in the test material nickel. Using a combination of the transient grating (TG) and Faraday techniques, we probe the magnetic dynamics of the intrinsically acoustic excitations. The dispersion characteristics of our excitations can be uniquely identified as arising from in-plane Rayleigh and longitudinal acoustic excitations while at particular values of applied external magnetic field, the acoustic excitation coherently couples to a k-vector tunable ferromagnetic resonance in the film. I will balance the talk between discussion of the experimental apparatus and its benefits as well as discussing the array of elastically actuated FMR, dipole-exchange spin waves, and nonlinearities that arise. I will also discuss open questions and potential collaborative work.

[1] J. Janusonis et al., APL 106, 181601 (2015).
[2] J. Janusonis et al., arXiv:1601.04350 (2016).

Abstract: Properties of random mixed states of dimension N distributed uniformly with respect to the Hilbert-Schmidt measure are investigated. We show that for large N, due to the concentration of measure, the trace distance between two random states tends to a fixed number ~D=1/4+1/π, which yields the Helstrom bound on their distinguishability. To arrive at this result we apply free random calculus and derive the symmetrized Marchenko-Pastur distribution, which is shown to describe numerical data for the model of coupled quantum kicked tops. Asymptotic value for the root fidelity between two random states, √F=3/4, can serve as a universal reference value for further theoretical and experimental studies. Analogous results for quantum relative entropy and Chernoff quantity provide other bounds on the distinguishablity of both states in a multiple measurement setup due to the quantum Sanov theorem. We study also mean entropy of coherence of random pure and mixed states and entanglement of a generic mixed state of a bi-partite system. For quantum channels, we show that their level density is also described by the Marchenko-Pastur distribution. This allows us to deduce some properties of the diamond norm of large dimensional quantum channels.

Abstract: Physics of transition metals and physics of f-electron elements belong to permanently fascinating subject. The experimental and theoretical research groups are interested in the mechanisms of fundamental interactions between atoms, leading to the formation of a specific crystal structures, the conditions for the formation of magnetic moments in metals and basic interactions between magnetic moments in the conditions of metallic bonds. The importance of the symmetry as well as the nature of the magnetic interactions between even distant partners are discussed and illustrated by selected systems. The correlation between the alloy’s composition and their degree of order are taken into consideration. The aim of the research presented here was to uncover the specific mechanisms leading to frequently noncolinear and incommensurate magnetic ordering of the alloys based on metals with the typical weakly localized magnetic moments, i.e. the elements of so-called 3d block coupled through band electrons as for example in light Actinides – 5f. During the search of the mechanisms responsible for long-range magnetic ordering of intermetallic systems based on simple p– and d–electron metals, in which, after all there is no dominance of effects such as magnetocrystalline anisotropy, the main attention was devoted to the aspects of symmetry of periodic commensurate crystal structures as well as commensurate and incommensurate magnetic ones. For the sake of clarity, a brief overview of known mechanisms of direct, indirect and super- exchange interactions of the Fe atoms, which have in the neighborhood p, d or f–electrons is given together with the general review of elementary sources of anisotropy due to the components of the measured compounds. All of the presented papers concern the results of experiments performed with the use of non-polarized neutron beams in the scenario of elastic and coherent scattering. Analysis of data collected for high symmetry directions allow determination of the details of magnetic interactions of exchange constants derived within the Weiss’ molecular field theory approximation of the crystal field or in the tensor resulting from a search of the exchange constants by Monte Carlo methods. Recent papers in this vein are trying to adopt the simplest models, namely the crystal field model in the conditions of the low recognition of the input anisotropy parameters of the commensurate UFe₄Al₈ and the distribution of magnetization in an incommensurate ScFe₄Al₈.

Abstract: Nonlinear crystals are typically used when interaction of different colors of light is requested. In classical optics these nonlinear phenomena are used for second-harmonic generation, sum-frequency generation, optical parametric amplification or many other effects. In quantum optics, dealing with optical interaction on the level of individual photons, the most prominent process is spontaneous parametric down-conversion (SPDC). Influence of magnetic field on these nonlinear processes was not thoroughly tested yet. This topic deserves intensive study both from theoretical and experimental point of view, because the magnetic field can decrease the symmetry of the nonlinear crystal and so it may allow to use new types of phase-matching conditions. We started to test the SPDC process in BBO crystals. BBO is a trigonal (3m) negative uniaxial material. Nonlinear magneto-optic tensor of this material is not known and we can hardly predict it. According to our first theoretical derivation the efficiency of the nonlinear processes has to oscillate when rotating the magnetic-field orientation.

Abstract: We have constructed a four-photon source for quantum information processing experiments. In comparison to others implementation our source generates two different photon pairs – entangled, separable or completely mixed in polarisation.

Abstract: The talk will discuss the measurement of collectibility entanglement witness on several two-qubit states. I will present our experimental setup, the measurement procedure and then compare obtained data with theoretical prediction.

Abstract: Self-organization in thermodynamics and quantum as well as classical mechanics is the result of spontaneous symmetry (ergodicity) breaking, i.e., a random choice in the past. Under specially tuned conditions, when the system reaches a critical dynamics, self-organization becomes hierarchical. The very self-organized criticality is possible only in open systems. We tested the hypothesis that the conformational transition networks of the natively disordered proteins have a self-organized critical structure. Using a formalism of the generalized fluctuation theorem, we shown that the biological molecular machines with such dynamics transduce not only energy but also organization, defined by the suitable physical variable. Like work and heat are changes in energy, information and entropy production/reduction are changes in this variable.

Abstract: Dendrymery są polimerami zbudowanymi z łańcuchów liniowych (spejserów) połączonych sukcesywnie, generacja po generacji, w regularną, hierarchiczną strukturę drzewiastą. W zależności od panujących w roztworze warunków makrocząsteczki te są neutralne bądź uzyskują ładunek elektryczny. Ze względu na specyficzną, rozgałęzioną architekturę szkieletu molekularnego dendrymerów, oddziaływania objętości wykluczonej i elektrostatyczne mają duży wpływ na ich własności konformacyjne. Na seminarium zostaną przedstawione wyniki badań nad pojedynczymi, neutralnymi i naładowanymi dendrymerami z giętkimi spejserami, które przeprowadzono za pomocą gruboziarnistych symulacji komputerowych metodą Monte Carlo. Symulacje te pozwoliły na analizę rozmiaru i struktury wewnętrznej dendrymerów w szerokim zakresie liczby generacji i długości spejserów. Dla dendrymerów obdarzonych ładunkiem wykonane obliczenia umożliwiły obserwację i jakościowy opis efektu ich „puchnięcia” w warunkach neutralnego i niskiego pH.

Abstract: Ultrasonic hyperthermia is a method of cancer treatment in which tumors are exposed to an elevated cytotoxic temperature using ultrasound (US). In conventional ultrasonic hyperthermia, the ultrasound-induced heating in the tumor is achieved through the absorption of wave energy. However, to obtain appropriate temperature in reasonable time, high US intensities, which can have a negative impact on healthy tissues, are required. The effectiveness of US for medical purposes can be significantly improved by using the so-called sonosensitizers, which can enhance the thermal effect of US on the tissue by increasing US absorption. One possible candidate for such sonosensitizers are magnetic nanoparticles with mean sizes of 10-300 nm, which can be efficiently heated because of additional attenuation and scattering of US. Additionally, magnetic nanoparticles are able to produce heat in the alternating magnetic field (magnetic hyperthermia). The synergetic application of ultrasonic and magnetic hyperthermia can lead to a promising treatment modality. [A. Józefczak et al., App. Phys. Lett. 108, 263701 (2016)].

Abstract: Numerical solutions of coupled Maxwell and Landau-Lifshitz-Gilbert equations for a magnetized yttrium iron garnet (YIG) sphere acting as a one-stage filter will be discussed. The filter will be analysed using finite-difference time-domain technique. Contrary to the state of the art, it will be shown that the maximum electromagnetic power transmission through the YIG filter occurs at the frequency of the magnetic plasmon resonance with the effective permeability of the gyromagnetic medium , and not at a ferromagnetic resonance frequency. Such a new understanding of the YIG filter operation, makes it one of the most commonly used single-negative plasmonic metamaterials. The frequency of maximum transmission is also found to weakly depend on the size of the YIG sphere. An analytic electromagnetic analysis of resonances in a YIG sphere is performed for circularly polarized electromagnetic fields.

Abstract: During the lecture I will briefly present the results of my and my group’s studies being conducted within the last six years. Most of them comes from the fundamental experimental studies performed using the optical spectroscopic techniques on photosynthetic proteins isolated from bacteria, algae, and plants. These studies contributed, among others to understanding the role of the protein dynamics in intraprotein electron transport. I will also present our attempts to use the photosynthetic proteins in solar cells.

Abstract: Quantum particles exhibit peculiar correlations that cannot be described by classical theories. These correlations are responsible for various physical phenomena and they lie at the heart of modern information theory. Additional complex features of quantum correlations are manifested when the underlying particles are fundamentally indistinguishable and when their dynamics occurs in interacting and open systems. In this talk I will present my recent results on how to describe, detect and model the evolution of quantum correlations in various scenarios. I will also discuss my future research directions related to this topic.

Abstract: The uncertainty principle, which states that certain sets of quantum-mechanical measurements have a minimal joint uncertainty, has many applications in quantum cryptography. But in such applications, it is important to consider the effect of a (sometimes adversarially controlled) memory that can be correlated with the system being measured. The information retained by such a memory can in fact diminish the uncertainty of measurements. Recently, different uncertainty relations in the presence of memory were formulated in terms of the von Neumann conditional entropy. However, the entropy is not the only measure that can be used to quantify conditional uncertainty. Here, we develop a general operational framework that formalizes the concept of conditional uncertainty in a measure-independent form. Our formalism is built around a mathematical relation that we call conditional majorization. We define and characterize conditional majorization and demonstrate the use of this framework by deriving measure-independent conditional uncertainty relation in a tripartite scenario. In particular, we provide a state-independent lower bound on the minimal joint uncertainty that two remote parties (Bob and Eve) have about the outcome of a given pair of measurements performed by a third remote party (Alice), conditioned on arbitrary measurements that Bob and Eve make on their own systems.

Abstract: With recent advances made in the design and development of multifunctional polymeric materials, elastomers derived from triblock copolymers are in a good position to meet contemporary materials challenges and explore new technological opportunities. In this spirit, we consider the versatility of thermoplastic elastomer (TPE) systems, which provide an attractive alternative to chemically cross-linked materials because of their ability to microphase-separate and form nanostructures connected by a physically cross-linked network capable of withstanding substantial deformation. We first consider the stimuli responsiveness of triblock copolymers in the presence of midblock-selective additives. Upon incorporation of a midblock-selective oligomer, the molecular network formed by such copolymers can be tunably swollen to yield highly elastic soft systems, which exhibit composition-tunable mechanical properties (including time-composition rheological equivalence), as well as remarkable electromechanical properties. The morphological features and mechanical properties of swollen TPE gel systems generated from commercial and model styrenic TPEs will be surveyed. These materials, subjected to electrical stimulation as electroelastomers (i.e., dielectric elastomers) between compliant electrodes, are shown to achieve actuation strains greater than 300% and electro­mechanical coupling efficiencies in excess of 90%. The electrostatic mechanism by which electroactuation proceeds, as well as comparisons with other materials, will be discussed. Unlike conventional dielectric elastomers composed of chemically cross-linked elastomers, these copolymer systems are easily processable and broadly tunable in terms of composition, concentration and molecular weight, and they exhibit little cyclic hysteresis. In the case of acrylic TPEs, electroactuation occurs without the need for mechanical prestrain (often required to thin specimens so that lower voltages can be used to achieve high fields). These same triblock copolymers can be designed in conjunction with liquid metals to yield ultrastretchable/flexible electronic wires and antennae capable of remaining conductive beyond 1000% strain, as well as with phase-change additives to impart high-fixity/recovery shape memory. Incorporation of a charged midblock permits addition of polar additives that can further extend the scientific and technological diversity of TPEs. Development of stimuli-responsive, hyperelastic and shape-recovering polymeric materials, such as those to be presented here, is critical for emerging applications such as (micro)robotics, microfluidics and various biomedical devices.

Abstract: We will discuss the transport properties of quantum dots coupled to superconducting and normal electrodes, focusing on the transport regime where the current flows due to Andreev reflection. In the case of weak coupling between the leads and the dot, we show that Andreev current exhibits a nontrivial dependence on the bias and gate voltages, which is also reflected in magnetoresistive properties of the device. Moreover, we predict a zero-bias anomaly of the Andreev differential conductance in the parallel configuration of leads’ magnetizations, which is associated with a nonequilibrium spin accumulation in the dot triggered by Andreev processes. On the other hand, in the case of strong coupling between the leads and the dot, we study the influence of electron pairing on the Kondo state and show that the emerging Kondo resonance can be significantly enhanced by increasing the coupling to superconducting lead.

Abstract: Dynamic magnetic phenomena, such as magnetization switching by spin transfer torque and the current-induced motion of domain walls, are strongly affected by spin relaxation. The Landau-Lifshitz-Gilbert equation which describes magnetization dynamics and is used as the basis for micromagnetic simulations, accounts for spin relaxation by the inclusion of the phenomenological damping term. The microscopic origin of the Gilbert damping is the spin-orbit interaction which also plays the key role in other effects of high relevance to spintronic applications. The talk will present quantum mechanical calculations of the Gilbert damping constant in magnetic layered systems (ferromagnetic films, ferromagnet/nonmagnet bi-, tri-, and multilayers built of transition metals) within the torque-correlation model. It will be reported how the damping constant depends on the type of nonmagnetic layers and the geometric dimensions of the considered structures. The origin of such dependences, including nonlocal damping in magnetic trilayers, will be analyzed using the spatial decomposition of the damping constant. In particular, the conditions for the enhancement of the Gilbert damping will be discussed.

Abstract: In all but the most trivial open quantum process, some amount information about a system’s state will be `remembered’ by its environment, influencing the system’s future evolution. However, in practice, the assumption of environmental `forgetfulness’ or Markovianity is almost always made. This is partly for practical reasons – until now there has been no unified framework to describe the most general non-Markovian quantum dynamics – but also remarkably, because the Markovian assumption appears to be valid in many cases. I will present a new scheme for operationally characterising non-Markovian quantum processes, which both gives a theoretical understanding of such processes and provides a recipe for reconstructing them experimentally. Moreover, this scheme yields a natural measure on the space of of all processes, which I will use to ask the question: how Markovian is nature on average?

Abstract: We point out a contrasting role the entanglement plays in communication and estimation scenarios. In the case of communication it brings benefits both at the detection and input stages, the facts known as output and input super-additvity respectively. On the other hand, in estimation it is only the entanglement of the input probes that enables performance enhancement and we do not observe output super-additivity. We identify a regime where a connection between concepts crucial to the two fields is demonstrated. This allows us to shed new light on the problem of super-additivity in communication.

Abstract: [PDF]  There is an abundance of anecdotal evidence that nanophases adsorbed within nanoporous materials can exhibit high pressures as a result of the confinement [1,2]. For example, phase changes and chemical reactions that only occur at high pressures in the bulk phase occur in the confined phase at bulk phase pressures that are orders of magnitude lower. The pressure in the pore is a second order tensor, and for simple pore geometries has both a normal pressure component (normal to the walls) and one or more tangential components (parallel to the walls). For simple fluids in pores that are up to a few nanometers in width, molecular simulations show that both the normal and tangential pressures can be locally very high (thousands or tens of thousands of bars) in the pore, even though the bulk phase in equilibrium with the pore is at a pressure of one bar or less. The cause of these high in-pore pressures will be discussed, and where possible comparison with experimental results will be made [3]. When the molecules in the confined nanophase react with each other chemically it may be possible to achieve even higher tangential pressures, in the megabar range. Evidence for this is provided by recent experiments on sulfur (an insulator at ambient conditions) in narrow single-walled carbon nanotubes, carried out by Kaneko and coworkers [4]. They find that the sulfur atoms within the pore covalently bond to form a one-dimensional phase that is metallic. In the bulk phase sulfur forms a metallic phase only at pressures above 95 GPa. In our recent molecular dynamics simulations of this system we find that the sulfur atoms are covalently bonded in the pore and that they experience tangential pressures in excess of 100 GPa as a result of the strong confinement [5].

[1] Yun Long, Jeremy C. Palmer, Benoit Coasne, Małgorzata Śliwińska-Bartkowiak and Keith E. Gubbins, “Pressure enhancement in carbon nanopores: A major confinement effect”, Physical Chemistry Chemical Physics, 13, 17163-17170 (2011).
[2] Yun Long, Jeremy C. Palmer, Benoit Coasne, Małgorzata Śliwińska-Bartkowiak, George Jackson, Erich A. Müller and Keith E. Gubbins, “On the Molecular Origin of High Pressure Effects in Nanoconfinement: Effects of Surface Chemistry and Roughness”, Journal of Chemical Physics, 139, 144701 (2013).
[3] M. Śliwińska-Bartkowiak,H. Drozdowski, M. Kempinski, M. Jazdzewska, Y. Long, J.C. Palmer and K.E. Gubbins, „Structural Analysis of the Behavior of Water Adsorbed in Activated Carbon Fibers”, Physical Chemistry Chemical Physics, DOI: 10.1039/C2CP22111J (2012).
[4] Y. Fujimori, A. Morelos-Gómez, Z. Zhu, et al., “Conducting Linear Chains of Sulphur Inside Carbon Nanotubes”, Nature Comm., 4, DOI 10.1038/ncomms3162 (2013).
[5] K.E. Gubbins, C.A Addington and J.M. Mansell, to be published.

Abstract: For desired applications, a deep knowledge of the materials optical properties should be thoroughly investigated to improve their efficiency and device development. The Raman spectroscopy has been proved to be a powerful nondestructive technique that enables the investigation of the structural, electronic and optical properties of semiconductors nanostructures. In this talk an overview of the fundamental theoretical aspects of Raman scattering in will be given. The potentialities of the technique on the characterization of different semiconductor structures, will discussed based on cases study. The effect of the strain and compositional effects on the optical phonons of semiconductors based alloys, doping effects on the polar optical phonons, resonant effects, and confined effects in nanostructures are highlighted.

Abstract: [PDF]  Magnetization manipulation is an indispensable tool for both basic and applied research. I will discuss some of the knobs to tune dynamics at ultrafast time scales. The dynamics of the response depends on the energy transfer from the laser excited electrons to the spins within the first femtoseconds. This determines the speed of the ultrafast magnetization: if the electrons are driven to a strong excitation density, a second slower process is found. This slowdown is a signature of the intrinsic ferromagnetic electron correlations in a ferromagnet. One possibility of control is to shape the properties of the electronic system. A special material of interest for magnetic storage development is FePt. This material allows an interesting modification of its density of states: Pt alloying increases the magnetic anisotropy and reduces the number of states at the Fermi level making it “more noble”. Consequently, the electron temperature shoots to higher values above the Curie temperature, a precondition for all-optical writing [1,2]. On the other side due to the non-equilibrium electron distribution, also ultrafast currents are generated and contribute to the laser driven spin dynamics. Similarly, to shaping the density of states in the first example, adjacent layers of a noble metals like Pt, Au or transition metals like W, Ta, Ru can shape the THz spin currents and convert ultrafast laser-driven spin currents via the ultrafast spin-Hall effect into a charge current burst. This opens a way towards novel THz spintronic devices: optimizing thicknesses and layers, we can realize efficient metallic THz spintronic emitters of ultra-broadband terahertz radiation competing with state-of-art photo-conductive switches THz emitters used for airport security [3,4].

[1] J. Mendil, P. C. Nieves, O. Chubykalo-Fesenko, J. Walowski, M. Münzenberg, T. Santos, S. Pisana, Sci. Rep. 4, 3980 (2014).
[2] U. Atxitia, O. Chubykalo-Fesenko, J. Walowski, A. Mann, and M. Münzenberg, Phys. Rev. B 81, 174401 (2010).
[3] T. Kampfrath, M. Battiato, P. Maldonado, G. Eilers, J. Nötzold, S. Mährlein, V. Zbarskyy, F. Freimuth, Y. Mokrousov, S. Blügel, M. Wolf, I. Radu, P. M. Oppeneer, M. Münzenberg, Nature Nanotech. 8, 256 (2013).
[4] T. Seifert, et al. arXiv:1510.03729

Abstract: In the presentation I will show the results of investigation on spin waves in periodic ferromagnetic structures (magnonic crystals). The patterning at nanoscale permits to alter the propagation of spin waves and modify their properties. The focus of study is put on the following topics related to spin waves properties: i) standing spin wave formation in magnonic crystals ii) metamaterial properties for electromagnetic waves propagating through magnonic crystal, iii) nonreciprocal dispersion of spin waves and iv) collective dynamical skyrmion excitations in the arrays of magnetic dots.

Abstract: Seminarium będzie kontynuacją zeszłorocznego seminarium profesora Ryszarda Tanasia, na którym zaprezentowane zostały wyniki dotyczące tzw. klasycznego splątania. Chciałbym przedstawić ujednolicony i uproszczony model kilku różnych eksperymentów (Phys. Rev. Lett. 88 (2002) 097902, Sci.Rep. 5 (2015) 9175, arxiv: 1406.3338, arxiv: 1511.02265, arxiv: 1511.08144), których wyniki autorzy interpretują w kategoriach nieklasycznych korelacji klasycznych obiektów. Prosty model pozwala na krytyczne odniesienie się do takich interpretacji i pozwala lepiej zrozumieć sens mierzonych parametrów.

Abstract: One of the pillars of the standard cosmological model is the observed distribution of galaxies on the largest scales, from our cosmic neighbourhood to the farthest possible distances. I will shortly describe how our knowledge of this distribution is being gathered thanks to galaxy surveys, with a short historical summary as well as the current status and future prospects. I will also mention examples of cosmological information that can be derived from such data and finally I will present my own and my collaborators’ work on such surveys, with an emphasis on data sets covering the full extragalactic sky.

Abstract: [PDF]  W referacie omówię wyniki badań prowadzonych w Katedrze Elektroniki AGH nad magnetycznymi złączami tunelowymi z anizotropią magnetyczną w płaszczyźnie i prostopadłą, zwracając szczególną uwagę na prąd krytyczny potrzebny do przełączenia magnetyzacji i stabilność termiczną złącza. Na przykładzie magnetorezystancyjnych nanoelementów (AMR, GMR i TMR), działających w oparciu o efekt diody spinowej przedyskutuję wzbudzenia jednorodnych modów FMR i fal spinowych.

Abstract: [PDF]  Wykorzystując samoorganizujący się wzrost wysp Au o rozmiarach kilkudziesięciu nanometrów na powierzchni warstwy Mo [1] oraz silną zależność anizotropii magnetycznej ultracienkiej warstwy Co od rodzaju bufora, na którym jest ona osadzana, wytworzono w systemie MBE (molecular beam epitaxy) układ epitaksjalnych kropek magnetycznych [2, 3]. Kropki stanowi ta część warstwy Co, która jest osadzona na powierzchni wysp Au. Są one otoczone matrycą – warstwą Co osadzoną bezpośrednio na powierzchni Mo, pomiędzy wyspami Au. W zależności od grubości warstwy Co kropki i matryca charakteryzują się różnymi wzajemnymi kierunkami namagnesowania. Szczególna uwaga poświęcona jest konfiguracji, w której kropki są namagnesowane prostopadle do płaszczyzny warstwy, a namagnesowanie matrycy leży w jej płaszczyźnie. Stan remanencyjny układu oraz procesy przemagnesowania kropek badane są przy pomocy techniki magnetooptycznej (PMOKE) oraz mikroskopii sił magnetycznych (MFM). Magnetyczny jednodomenowy charakter w dużym zakresie rozmiarów kropek wynika z wysokiej jakości ich struktury krystalicznej. Skorelowano wielkość pola przełączania magnetycznego kropek z ich rozmiarami. Przeprowadzono symulacje mikromagnetyczne ilustrujące procesy przemagnesowania kropek oraz profile namagnesowania [4]. Symulacje te wykonano dla rozmiarów i kształtów kropek obserwowanych w eksperymencie. Poddano również analizie wpływ wewnętrznej struktury kropek typu core/edge. Zaproponowano diagram fazowy stanów magnetycznych i mechanizmów przemagnesowania kropek w funkcji parametrów opisujących ich strukturę.

[1] A. Wawro et al., Nanotechnology 21 (2010) 335606.
[2] A. Wawro et al., Europhys. Lett. 89 (2010) 37003.
[3] A. Wawro et al., Phys. Rev. B 83 (2011) 092405.
[4] E. Milińska and A. Wawro, J. Appl. Phys. 116 (2014) 193905.

Abstract: The contribution of two types of cascading process to the nonlinear optical diffraction of electromagnetic waves from a standing acoustic wave in a GaAs crystal is theoretically studied. The first type of cascading process results from second-harmonic generation followed by linear acousto-optical diffraction, while the second type involves linear acousto-optical diffraction from the standing acoustic wave and subsequent sum-frequency generation. In contrast to the third, direct, nonlinear acousto-optical diffraction process we previously investigated, the photoelastic interaction between electromagnetic and acoustic waves is here linear. We establish the rules governing the cascading processes and show that in most cases the output signal simultaneously results from two or even three of the possible nonlinear diffraction mechanisms. However, we demonstrate that a careful choice of the incidence angles of the incoming electromagnetic waves, of the polarization combinations of the incoming and diffracted waves, and of the type of acoustic wave (longitudinal or transverse) makes it always possible to distinguish between the direct and either of the two cascading processes.

Abstract: RNA has a complicated tertiary architecture and its internal dynamics is often related to function. To investigate the flexibility of RNA molecules we apply molecular dynamics simulations using different approximations; from all-atom representation in explicit solvent to simplified coarse-grained models. I will present examples of applications of molecular dynamics simulations to ribosomal RNA and experiments to determine thermodynamics of various ribosomal RNA fragments.

Abstract: A new concept of structuring fixed charges in the nanoscale for optimum ion exchange performance is introduced. Crystalline porous charge exchange materials such as zeolites are inflexible and are restricted to cation exchange. Polymer resins have irregular porous structures. Fixed charges hidden by hydrophobic forces are exposed only after swelling in aqueous immersion. Threading polyelectrolyte chains into metal organic frameworks (MOF) form a superior ion exchange material that possesses advantages of both ceramic and polymeric domains. We report two new composites of polyelectrolytes synthesized within a MOF structure [1, 2].
Cation exchange function is provided by sodium poly(4-styrene sulfonate) threaded in MIL-101 denoted as NaPSS MIL-101.[1] It is synthesized directly with polymerization in situ of the MOF, as shown in Figure 1. The NaPSS MIL-101 polyelectrolyte threaded in MOF has high surface area of 1850 m2/g and a large specific volume 0.85 mL/g. Figure 2(a) compares the ion adsorption kinetics to commercial ion-exchange resin IR-120. Excellent selectivity based on charge is demonstrated when NaPSS MIL-101 is immersed into a solution of two organic dyes, as shown in Figure 2(b). The anionic Acid Blue 9 is excluded though it has significant van der Waals affinity to high surface porous materials.Another example of polyelectrolyte synthesized in MOF is demonstrated by anionic polyvinyl benzyl trimethylammonium hydroxide (PVBTAH) threaded in ZIF-8 (PVBTAH ZIF-8), with structure shown in Fig. 3 [2].
The high porosity, high surface area, uniform and ordered structure of metal organic frameworks provide fast reversible ion transport in a rigid nanoporous structure. On the other hand polyelectrolyte chains have their charges well separated and organized by the MOF framework, with reversible and local flexibility for ion-exchange function, as illustrated in Figure 3. This is analogous to the Lattice-Boltzmann model of discretizing and localizing dynamics of polymeric chains over a grid.

[1] Liang Gao, Chi-Ying Vanessa Li, and Kwong-Yu Chan, “Polystyrene Sulfonate threaded in MIL-101Cr(III): a Cationic Polyelectrolyte Synthesized Directly into a Metal-Organic Framework”, Chem. Mater. DOI: 10.1021/cm504623r. Publication Date (Web): April 30, 2015.
[2] L. Gao, C.Y. V. Li, K.Y. Chan, and Z.N. Chen, “Metal-Organic Framework Threaded with Aminated Polymer Formed in Situ for Fast and Reversible Ion Exchange”, J. Am. Chem. Soc. 136 (2014) 7209-7212.

Abstract: Ferroelectric materials offer a wide range of useful properties such as spontaneous polarization, pyroelectric, piezoelectric, and electro-optic effects that can be applied in non-volatile memories, actuators, transducers, and thermal sensors. From technological point of view several important issues concerning applications of ferroelectrics (like size effects, one dimensional structures, lead-free materials, multiferroic bismuth ferrite) are important and will be presented in this talk. Perovskites and perovkite-like compounds are conventionally obtained by solid-state reactions or wet-chemistry. The methods are related to high production costs and have serious disadvantages. A much less expensive alternative to the chemistry-based techniques is a direct synthesis from respective oxides at room temperature via mechanically triggered chemical reaction. The room temperature synthesis lowers the fabrication costs, eliminates the undesirable losses of volatile elements and enables the control of chemical and stoichiometry composition. The method has been recently used to obtain nanocrystalline electroceramic materials of perovskite structure like BiFeO₃, PZT, Ba(Ti,Ca)O₃, Ba(Fe_1/2Nb_1/2)O₃, Bi₃TiNbO₃. The influence of the mechanochemical synthesis or mechanical activation on the final properties of the nanopowders and/or ceramics (obtained from those powders) will been discussed.

Abstract: Using the model of parametric interaction based on the spatio-spectral Schmidt modes and generalized parametric approximation, we analyze coherence and mode structure of ultra-intense twin beams generated in the regime with pump depletion. We show that the increase of spatial and spectral coherence with the increasing pump power observed for moderate powers is replaced by the decrease for the pump powers at which pump depletion occurs. This behavior of coherence is opposed to that exhibited by the number of spatio-spectral modes effectively constituting the twin beam. The conditions for maximal coherence are analyzed considering pump-beam parameters (spectral width, transverse radius). The existence of additional coherence maxima occurring at even higher pump powers is predicted and explained by the oscillatory evolution of the modes’ populations. Comparison with the experimental results is discussed.

Abstract: [PDF]  Located at 8kpc only, the Galactic Center allows studying a galactic nucleus in unparalleled detail. With the advent of high-resolution, near-infrared instrumentation in the last decade it became possible to follow individual stellar orbits around the radio source Sgr A* with orbital periods as short as 12 years. The orbits provide compelling evidence for the massive black hole paradigm. The next generation near-infrared instrument GRAVITY aims at interferometrically combining the light of the four telescopes of ESO’s VLT. The higher resolution will allow monitoring stellar orbits with orbital periods of 1 year only, and the relativistic prograde periastron precession gets accessible. The astrometric accuracy of GRAVITY is of order of the event horizon size of Sgr A*. This means that we might have access to measuring the spin of Sgr A*. In the past few years the small gas cloud G2 has been approaching Sgr A*. We were able to follow the tidal evolution of G2 for a decade, beautifully showing how the object got stretched ever more and how it passed the point of closest approach in 2014. The cloud is a unique probe of Sgr A*’s atmosphere, and we have observational hints that gas passing so close to Sgr A* experiences a drag force.

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Abstract: Stars form continuously in the dense and cold molecular clouds in our Galaxy. At the earliest stages of their formation, the proto-stars are surrounded by large amounts of dust and gas which make them invisible in the optical light. The most useful are in fact far infrared wavelengths containing the maximum of the dust emission and the key molecular transitions. The latter are a powerful tool to investigate the physical conditions of the gas and thus the physical phenomena at play during the star formation. In my talk, I will present the state-of-the-art spectroscopy of star forming regions from the Herschel Space Telescope. I will show how the observations of interstellar molecules such as water and carbon monoxide help astronomers to understand the physics of essentially hidden stages of star formation.

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Abstract: In order to control a quantum system, we need the full information on its Hamiltonian. Yet, how can we know all the entries of a Hamiltonian matrix, especially when the system is large and our access is limited? The problem of Hamiltonian identification under limited access has recently been studied quite actively. Here, after reviewing our results, we ask a more ambitious question along the same lines; what if we don’t know anything about the system and we still attempt to estimate its Hamiltonian through a small gateway? We shall discuss how we can probe such an ‘untouchable’ system E through a small gateway system S, paying a close attention to the equivalence class induced by the limitedness of access. The insight obtained hereby would open up a possibility of controlling a large quantum system with only a few parameters.

Abstract: The paradox of Maxwell’s demon is probably the most famous example, in which physics (particularly thermodynamics) and the concept of information are linked. The tricky point of this paradox is in the necessity of the quantitative consideration of information acquisition by measurement. The related argument strengthened our notion that information processing is physical, and formed a firm basis of the science of quantum information. We will review the history of the efforts to resolve the paradox, the final exorcism by Landauer and Bennett, as well as some interesting consequences of the 2nd law [1].

[1] Koji Maruyama, Franco Nori, and Vlatko Vedral, Rev. Mod. Phys. 81, 1 (2009) .

Abstract: Mathematica is a software that was originally developed for researchers in mathematics and physics. Since its first release 26 years ago, it has evolved so greatly that it can now be applied to virtually everything, such as data visualisation, image processing, financial engineering, machine learning, etc., to name a few. We will cover as many functions it has as possible to impress you, and will answer any questions.

Abstract: Magnetic nanostructures, that are patterned on the length scale of the dipole and exchange interaction, have gained significant scientific interest in the past years [1-6]. These nanostructures have great potential for technological applications in data processing and storage, and spintronics [1-6]. However, the measurement of their microscopic magnetisation behaviour is challenging. For this task we use a combination of fast MOKE based first-order reversal curve (FORC) measurements, that we recently developed [7], and x-ray microscopy with XMCD contrast at our own endstation MAXYMUS@BESSY. FORC allows the magnetic separation of individual magnetisation reversal processes without the need for high lateral resolution. X-ray microscopy on the other hand yields a detailed nanoscopic image of the magnetisation and allows the observation of magnetisation dynamics on a picosecond timescale. To showcase the capabilities of these two powerful methods an antidot lattice (ADL) based magnonic crystal is discussed, among others. FORC and static x-ray imaging provide a detailed insight into the very complex and orientation dependent magnetisation reversal processes of ADL samples. The full magnetisation reversal is achieved by a combination of several reversible and irreversible steps that could not have been distinguished by conventional magnetometry. Subsequently, the time resolution capabilities of x-ray microscopy are leveraged to directly observe the individual spin wave modes in the magnonic crystal in the range from 250 MHz up to 8 GHz. Finally, the understanding of the static and dynamic magnetisation behaviour of these magnonic crystals allows tuning the magnon propagation length within the ADL in a range from 0.5 to 15 µm, thus, realising a simple spin wave filter.

[1] Lenk, B. et al.: Phys. Rep. 507 (2011), 107
[2] Haiming, Y. et al.: Nat. Commun. 4 (2013), 2702
[3] Heyderman, L. J. et al.: Phys. Rev. B 73 (2006), 214429
[4] Schwarze, T.; Grundler, D.: Appl. Phys. Lett. 102 (2013), 22
[5] Manzin, A.; Bottauscio, O.: J. Phys. D – Appl. Phys. 45 (2012), 095001
[6] Haering, F. et al.: Nanotechnology 24 (2013), 055305
[7] Gräfe, J. et al.: Rev. Sci. Instr. 85 (2014), 023901

Abstract: The seminar will be focused on the magneto-hydrodynamic stirring of electrolyte in the combined electric and magnetic fields. We will present the estimations of the order of magnitude of the gradient magnetic force, gradient paramagnetic force, Lorentz force and damping force acting on ions embedded in aqueous electrolytes. The focus will be given to influence of magnetic field on the effectively para- and diamagnetic products of electrochemical reactions and the effects of phase separation under inhomogeneous magnetic field and Earth gravitation will be discussed. We will discuss also the influence of stray magnetic field of the ferromagnetic electrodes on a deposit structure and electrokinetic effects under inhomogeneous magnetic field.

Abstract: [PDF]  Due to the increasing demand in high-density recording media, magnetic thin films with high magnetic anisotropy are widely studied in order to overcome the superparamagnetic effect. To fulfill the requirements of thermal stability, hard magnetic alloys, i.e. FePt alloys in the L10 phase are promising candidates as storage layer. However, owing to the large magnetic anisotropy, the magnetic field required to reverse the magnetization of the media may become higher than the field provided by a conventional recording head. To solve this, so-called writeability issue, the concepts of exchange-coupled composite (ECC) media as well as bit patterned media based on L10 FePt [1] were suggested, which will be discussed in this presentation. Furthermore, ultrafast magnetization switching is at the heart of both modern information storage technology and fundamental science. In this regard, it was recently observed that ultra-fast magnetization reversal processes can be induced by circularly polarized laser pulses in amorphous ferrimagnetic GdFeCo alloy thin films [2]. This novel observation resulted in a broad range of exciting and challenging fundamental questions, and may enable new applications based on ultra-fast spintronics. An overview of our activities on all-optical switching in amorphous ferrimagnetic Tb-Fe alloy films [3-5] will be presented.

[1] C. Brombacher, M. Grobis, J. Lee, J. Fidler, T. Eriksson, T. Werner, O. Hellwig, and M. Albrecht, Nanotechnology 23, 025301 (2012).
[2] C. D. Stanciu, F. Hansteen, A. V. Kimel, A. Kirilyuk, A. Tsukamoto, A. Itoh, and Th. Rasing, Phys. Rev. Lett. 99, 047601 (2007).
[3] A. Hassdenteufel, B. Hebler, C. Schubert, A. Liebig, M. Teich, M. Helm, M. Aeschlimann, M. Albrecht, and R. Bratschitsch, Advanced Materials 25, 3122 (2013).
[4] C. Schubert, A. Hassdenteufel, P. Matthes, J. Schmidt, M. Helm, R. Bratschitsch, and M. Albrecht, Appl. Phys. Lett. 104, 082406 (2014).
[5] A. Hassdenteufel, J. Schmidt, C. Schubert, B. Hebler, M. Helm, M. Albrecht, and R. Bratschitsch, Phys. Rev. B 91, 104431 (2015).

Abstract: The talk is dedicated to the hybrid propagation, scattering, reflection, and absorption regimes that can be obtained in the advanced but still simple photonic structures and their microwave prototypes. Various manifestations of the diffraction inspired asymmetric transmission, a general phenomenon arising when using linear, isotropic, passive materials together with spatial inversion symmetry breaking, will be considered in the different structures, which include photonic crystal gratings, gratings made of ultralow-index materials, gratings based on hole-array metamaterials, and thin metallic gratings with a single subwavelength hole. The basic scenarios of directional selectivity achievable with the aid of these structures and their possible applications will be discussed. Then, the attention will be paid to ultrathin chiral metamaterials based on the coupled arrays of subwavelength resonators, which enable efficient polarization conversion and relevant channel and direction selectivity. The next topics will include reflection-enhanced absorption in photonic crystals made of polar dielectrics, multiple slow waves in graded-index photonic crystals, invisibility obtainable using high-index shells, and surface plasmons in deep annular-hole arrays. Finally, the transmission-mode spatial (angular) filtering in regular photonic crystals will be discussed alongside the reflection-mode spatial filtering, blazing, and splitting in thin reflector-backed gratings.

Abstract: Quantum information cannot be copied perfectly, in contrast with information from the “classical world”. In other words, one is not able to copy perfectly an arbitrary quantum state. In terms of monogamy, if one wants to prepare some number of copies of the initially unknown quantum state, fidelities of cloning cannot be all equal to 1, there is a trade-off. This basic feature is known as ’no-cloning theorem’ and was recognized by Wootters, Zurek and Dieks. But still there is possibility for imperfect cloning. Using group-theory formalism, we show that the allowed region for fidelities can be expressed in terms of overlaps of pure states with irreducible representations of the partially transposed permutation operators. Additionally, it is sufficient to take pure states with real coefficients only, which makes calculations simpler. To obtain the allowed region, we make a convex hull of possible ranges of fidelities related to a given irreducible representations.

Abstract: Of course not, but if one believes that information cannot be destroyed in a theory of quantum gravity, then we run into apparent contradictions with quantum theory when we consider evaporating black holes. Namely that the no-cloning theorem or the principle of entanglement monogamy is violated. Here, we show that neither violation need hold, since, in arguing that black holes lead to cloning or non-monogamy, one needs to assume a tensor product structure between two points in space-time that could instead be viewed as causally connected. In the latter case, one is violating the semi-classical causal structure of space, which is a strictly weaker implication than cloning or non-monogamy. This is because both cloning and non-monogamy also lead to a breakdown of the semi-classical causal structure. We show that the lack of monogamy that can emerge in evaporating space times is one that is allowed in quantum mechanics, and is very naturally related to a lack of monogamy of correlations of outputs of measurements performed at subsequent instances of time of a single system. This is due to an interesting duality between temporal correlations and entanglement. A particular example of this is the Horowitz-Maldacena proposal, and we argue that it need not lead to cloning or violations of entanglement monogamy.

Abstract: Environment care has now become a global societal challenge, on which physics and chemistry can turn to be leading actors and innovation leaders, especially in the domains of energetic transition, green nanoscience or ecomaterials. As an example, a great attention has been recently paid to the control of volatile organic compounds (VOCs) in home and working environments. Breakthroughs in the captation of VOCs have been achieved thanks to the mastering of novel porous nanomaterials, able to selectively filter or coadsorp molecular species. However, several scientific locks remain, related to the intricate balance of amphiphilic interactions and hydrogen-bond structures responsible for the behaviour of gaseous or liquid mixtures in nanopores. The physical parameters governing the nanostructures and the molecular dynamics of complex binary liquids confined in porous solids remain essentially unknown. We present here a general view of a model molecular binary system made of a ternary alcohol and an aprotic liquid, confined inside nanoporous silicas or carbons. Through a global experimental approach, we detail how the subtle balance of hydrophilic or -phobic interactions with interfaces in a nanoporous solid can lead to surprising nanostructures in the binary, and strongly affect both the hydrogen bonds network and the molecular dynamics of the system. We tentatively propose general routes for controlling coadsorption and/or nanofiltration of these complex binaries by tailoring specific nanoporous interfaces.

Abstract: One of the fundamental outcomes of the modern nuclear theory of is the prediction of the “stability islands” in the domain of the hypothetical super heavy elements. The enhanced stability has been expected for the deformed nuclei near Z=108 and N=162, yet much stronger effect has been predicted for heavier spherical nuclei close to the shells Z=114 and N=184. The talk is devoted to the experimental verification of these predictions – the synthesis and study of both the decay and chemical properties of the new elements.
    The synthesis of the heaviest nuclei with high neutron excess has been carried out in the fusion reactions of U and the isotopes of man-made elements: from Np up to Cf with the Ca-48 projectiles in 2000-2015. The decay properties of the 52 synthesized nuclei – the isotopes of elements 104-118 – obtained in 48Ca-induced reactions presents direct experimental evidence of the existence of the super heavy nuclei that considerably expand the Periodical Table of the chemical elements.
    Simultaneously in the chemical studies of elements 112-114 by methods of absorption gas chromatography the influence of the “relativistic effect” on the chemical properties of the super heavy elements was obtained for the first time. The possibilities of further theoretical and experimental investigations in close collaboration with many European and American laboratories connected with construction in Flerov Laboratory “Super Heavy Element Factory” are also discussed.
    In the talk are used the results obtained in FLNR (JINR, Dubna) in collaboration with LLNL, (Livermore, USA), ORNL (Oak-Ridge, USA), and Vanderbilt University (Nashville, USA), Texas A M University (College Station, USA) as well as GSI (Darmstadt, Germany), PSI (Villigen, Switzerland) and RIKEN (Tokyo, Japan).

Dodatkowe informacje: Profesor Oganessian należy do liderów w skali światowej w dziedzinie wytwarzania i badania własności fizycznych i chemicznych super ciężkich pierwiastków. Super ciężkie jądra atomowe tych pierwiastków stanowią obiekt zaawansowanych badań teoretycznych i eksperymentalnych prowadzonych w najlepszych centrach badawczych – głównie w Dubnej, USA i Niemczech. Profesor jest świetnym wykładowcą potrafiącym z pasją przedstawiać najnowsze wyniki badań.

Abstract: Block copolymers containing ionic pendant groups, or block ionomers, have become increasingly popular due to their potential application as fuel cell and water desalination membranes, as well as components in photovoltaic devices and polymeric actuators. Block ionomers hold promise in these applications because of their inherent ability to form separate ionic and nonpolar microdomains at nanoscale dimensions. Segregation of ionic and nonpolar segments enables simultaneous water, or ion, transport and mechanical robustness. This is especially true when ionic segments are located in the midblock of a multiblock copolymer. The ionic and nonpolar blocks are, however, highly incompatible, which can lead to long-term metastable morphologies. While thermal annealing is typically used to refine block copolymer self-assembly to equilibrium structures, most block ionomers have inaccessible glass transition temperatures, thereby making thermal annealing ineffective. The establishment of morphological control in block ionomers represents the main challenge preventing widespread use. Here, we explore a variety of nanostructures formed during solution casting and then investigate a facile means by which to equilibrate the morphological behavior of a midblock-sulfonated pentablock ionomer. A combination of transmission electron microscopy and tomography (TEM/T) and small-angle X-ray scattering (SAXS) are used to probe nanostructural features present in films produced from different casting strategies. Results indicate that solvent-templating of nano-features following solution casting is prominent, but that subsequent solvent vapor annealing can be effective in equilibrating the morphology. To the best of our knowledge, these results provide the first evidence of morphological control/refinement in a block ionomer of commercially relevant molecular weight.

Abstract: The single-molecules techniques are revolutionizing our understanding of biological processes and molecular mechanisms used by individual protein machines. I will introduce smFRET method and show how it was used to “observe” multiple conformational changes within recombination complex, acting in late stages of bacterial chromosome segregation, directly showing how recombination is activated and regulated. On the other hand, the real challenge in biology is to observe how individual proteins perform their function within living cell. I will present super-resolution microscopy and the ways I explore it to understand how individual UvrA and UvrB initiate pathway of DNA repair. I will show how these novel biophysical methods are changing our understanding of DNA repair process.

Abstract: Recently photoinduced dynamics in organic solid materials have attracted more attention in terms of not only the fundamental physics but also the application to low-cost photo-electronic devices. However, photoinduced processes in organic materials are more complicated than those in inorganic solid materials due to their flexible and soft structures [1]. Time-resolved infrared vibrational spectroscopy is one of the ideal tools for studying these dynamics because a vibrational peak is sensitive to both local charge and structure in an organic solid material. We applied this method to the photoinduced phase transition in organic crystals and found that the different dynamics of charge and structure accompanied by the phase transition [2-4]. We also studied the initial photoexcited processes in metal complexes including a spin crossover complex and found the state which has not observed by the other methods [5]. Moreover, we confirmed that the results obtained by time-resolved vibrational spectroscopy is in good agreement with those by more structure sensitive time-resolved method, that is, time-resolved electron diffraction [6]. [1] K. Onda, et al. Acc. Chem. Res. 47, 3494 (2014).
[2] Y. Matsubara, et al. J. Phys. Soc. Jpn. 80, 124711 (2011).
[3] N. Fukazawa, et al. J. Phys. Chem. C 116, 5892 (2012).
[4] N. Fukazawa, et al. J. Phys. Chem. C 117, 13187 (2013).
[5] T. Mukuta, et al. Inorg. Chem. 53, 2481 (2014).
[6] M. Gao, et al. Nature, 496, 343 (2013).

Abstract: Quantum process tomography (QPT), the full experimental determination of a quantum process, is usually used for benchmarking known systems. Here, I show how, by applying a large, controllable external bias, QPT of a two-level probe system can be used to determine a great deal about an unknown environment – including properties of its state and spectrum. The protocol I will discuss relies on few assumptions and could thus be applied to many systems of experimental interest, such as Bose-Einstein condensates, superconducting circuits and atoms in optical cavities. Within this talk, I will also discuss how one can do tomography for processes with initial correlations and hence those which are non-Markovian.

Abstract: The mission of the ESA Herschel satellite was completed in April 2013 after quite 4 years of activity. However, the incredible results of this far-infrared space observatory continue to revolutionize our view of the Universe. In particular, our knowledge of our Galaxy, of the stars and of our solar system has made significant progress thanks to the work carried out with this telescope, especially by the european teams. The formation mechanisms and the evolution of stars, of a few solar masses or greater, have revealed themselves a little more precisely: thanks to Herschel images and spectroscopic observations we now have a more global view of the genesis of stars and of their chemistry. The first complete observations of the water molecule allowed us to estimate the very significant amounts of water that exist in any planetary system in formation, but also to address the crucial question of the origin of water (and therefore life) on our own Earth.

Abstract: Recently a number of papers appeared in which the notion of “classical entanglement” and its role in optical processes has been discussed. There are some experimental results already published showing that “classical entanglement” is sufficient to violate Bell’s inequalities. This can have important implications for commonly accepted interpretation of some physical phenomena. The talk is aimed to present some of these, still controversial, results.

Abstract: The exact Bethe eigenfunctions for the heptagonal ring within the isotropic XXX model exhibit a doubly degenerated energy level in the three-deviation sector at the centre of the Brillouin zone. I will demonstrate an explicit construction of these eigenfunctions by use of algebraic Bethe Ansatz, and point out a relation of degeneracy to parity conservation, applied to the configuration of strings for these eigenfunctions. Namely, the internal structure of the eigenfunctions (the 2-string and the 1-string, with opposite quasimomenta) admits generation of two mutually orthogonal eigenfunctions due to the fact that the strings which differ by their length are distinguishable objects.

Abstract: The creation of ensembles of entangled particles triggered the studies of fundamental aspects of quantum mechanics. The ability to generate non-classical correlations between atoms opened the possibility for their practical applications in non-trivial ways, for example in quantum computation or ultra-precise metrology. However, before the implementation stage, we must first make sure that the entanglement is present in the system, which is often a difficult task. In this seminar I will present the experiments that were conducted to verify existence of non-classical correlations in ultracold atomic systems. Then I provide a simple and experimentally accessible criterion for particle entanglement in many-body systems. This is based on a violation of the Cauchy-Schwarz inequality for the second order correlation function. It applies to any system of identical bosons with either fixed or fluctuating number of particles, provided that there is no coherence between different number states.

Abstract: I will present very simple analytical formulas for calculation of multipartite and bipartite entanglement of one-magnon states in quantum spin systems. Regarding the multipartite entanglement I will present formulas for global entanglement and N-concurrence and show that they are mutually related. In the bipartite case, I will give formulas for I-concurrence and negativity, and show that they are also scalable. For one-magnon Schur-Weyl states I will show that the bipartite entanglement structure is completely coded in the corresponding Young tableau.

Abstract: Some problems (such as factorization of large numbers into a product of primes) which seem to be difficult for a classical computer turned out to be very simple for a quantum computer. Is it a general pattern or are there some problems which are too difficult even for quantum computers?

Abstract: Low frequency gyrotropic dynamics (100 MHz range) in arrays of the interacting magnetic vortex state dots are considered. The interdot dynamical magnetostatic interactions are accounted in the form of explicit multipole decompositions on the inverse dot center-to-center distance. Particular case of the dot clusters consisting of 3 or 4 laterally placed cylindrical ferromagnetic dots on a nonmagnetic substrate in the form of equilateral triangles or squares is calculated. The eigenfrequencies of collective magnetic vortex oscillations are calculated analytically and compared with recent experiments conducted on the clusters of permalloy dots.

Abstract: [PDF]  The spin-wave dispersion is inherently complex and anisotropic, depending on both several magnetic parameters of the magnonic medium and the angle between the spin-wave vector and effective magnetic field. We have used time-resolved scanning Kerr microscopy and micromagnetic simulations to study the propagation of spin waves across Permalloy and yttrium-iron-garnet (YIG) waveguides, arranged to form junction structures and biased asymmetrically. We demonstrate that the non-uniformity of the internal magnetic field and magnetization inherent to patterned magnetic structures can create a medium of graded refractive index for propagating magnetostatic waves and can be used to steer their propagation in magnonic architectures. The character of the non-uniformity can be tuned and potentially programmed using the applied magnetic field. Thus, our findings suggest a possibility of a novel reconfigurable computing and / or signal processing technology based on the principles of the graded-index magnonics. [PDF] 

Abstract: Magnetyczne układy warstwowe i wytwarzane z nich nanostruktury są przedmiotem badań wielu laboratoriów. Zainteresowanie tymi układami wynika z licznych, już zrealizowanych oraz perspektywicznych, zastosowań. Dotyczą one głównie technologii informatycznych oraz różnego typu elementów spintronicznych. Szczególnie interesujące są takie układy warstwowe, w których lokalna modyfikacja właściwości magnetycznych w płaszczyźnie warstw prowadzi do uzyskania specyficznej struktury magnetycznej, której realizacja w układach jednorodnych nie jest możliwa. Omówionych zostanie kilka przykładów modyfikacji anizotropii lub oddziaływania w układach warstwowych wykazujących anizotropię prostopadłą (Au/Co/Au, Pt/Co/Pt). Zmiany anizotropii w płaszczyźnie struktur uzyskiwano poprzez wytwarzanie warstw z kontrolowanym gradientem grubości (warstwy klinowe) lub w wyniku bombardowania jonowego. Bombardowanie warstw Au/Co jonami He lub Ar przez maski utworzone z regularnej dwuwymiarowej sieci nanokulek polistyrenowych, pozwoliło wytworzyć jednorodną sieć sztucznych domen umieszczonych w matrycy o kontrolowanych właściwościach magnetycznych [1]. Takie struktury są interesujące ze względu na możliwość wykorzystania do zapisu informacji. Uzyskanie monotonicznych zmian anizotropii lub oddziaływania międzywarstwowego pozwala na realizację procesu przemagnesowania poprzez, kontrolowaną jednorodnym polem magnetycznym, propagację pojedynczej prostej ściany domenowej [2-3]. Taki kontrolowany ruch ściany domenowej znajduje szereg potencjalnych zastosowań np., jako sensory magnetooporowe [3] lub układy typu lab-on-a-chip wykorzystujące pole rozproszone nad ściana domenową do transportu funkcjonalizowanych cząstek magnetycznych. [1] P. Kuświk inni, Nanotechnology 22, 095302 (2011); Nanotechnology 23, 475303 (2012).
[2] M. Urbaniak i inni, Phys. Rev. Lett. 105, 067202 (2010).
[3] M. Matczak i inni, J. Appl. Phys. 114, 093911 (2013); Nanoscale Research Letters 9, 395, (2014); Appl. Phys. Lett. 100, 162402 (2012).

Abstract: We deal with the models of nonlinear quantum oscillators, described by the Kerr-like nonlinearities. The oscillators can interact with each other and with external environment in various ways. Such models are usually associated with optical nonlinear couplers and discussed in the context of the properties of light they generate [1]. The Kerr-like models discussed here can be treated, under some conditions, as nonlinear quantum scissors, because of their ability to limit substantially the number of states which are essential in the system’s dynamics [2,3]. Moreover, this mechanism leads to creation of 2-qubit, 2-qutrit or qutrit-qubit systems for the discussed models. We will present the necessary conditions for creation maximally or almost maximally entangled states within such systems. Additionally, we will present different types of disentanglement in amplitude and phase damping reservoirs. For the models considered here we can observe asymptotic entanglement decay, death or entanglement revival. The conditions for such behavior will be presented. [1] J. Perina Jr., J. Perina, Progr. in Opt. 41, 361, (2000).
[2] W. Leoński and A. Kowalewska-Kudłaszyk, Progress in Optics, 56 131 (2011).
[3] A. Kowalewska-Kudłaszyk and W. Leoński, JOSA B, 31, 1290 (2014).

Abstract: It has been shown experimentally, that when two magnetic layers are separated by a thin nonmagnetic one there is an exchange (RKKY) coupling between the magnetic layers, which oscillates between ferromagnetic and antiferromagnetic types when thickness of the spacing layer is changed [1]. Exchange coupled magnetic layers have a vast range of applications in spintronics with number of advantages over single magnetic layers. In magnetic spin valves they are utilized not just like current polarizers with negligible stray field but also as composite free layers offering novel possibilities of manipulation with magnetic moments by means of spin transfer torque. Thus, in the talk, current-induced switching of composite free layers with antiferromagnetic interlayer coupling shall be reviewed [2]. On the other hand, spin waves in layered magnetic structures have been extensively studied, both experimentally and theoretically, in the 80-ties and 90-ties of the past century [3]. Very recently a possibility of spin current induced spin wave excitation in magnetic insulators have been demonstrated [4]. Therefore, in the second part of the talk, influence of spin pumping and spin current on the spin wave spectra of two exchange coupled ferromagnetic insulators shall be discussed. This work has been carried out within the Project NANOSPIN PSPB-045/2010 supported by a grant from Switzerland through the Swiss Contribution to the enlarged European Union. [1] S. S. P. Parkin, N. More, and K. P. Roche, Phys. Rev. Lett. 64, 2304 (1990).
[2] P. Baláz, J. Barnaś, Phys. Rev. B 88, 014406 (2013).
[3] M. Vohl, J. Barnaś, and P. Grünberg, Phys. Rev. B 39, 12003 (1989); J. Barnaś and P. Grünberg, J. Magn. Magn. Mater. 82, 186 (1989).
[4] Y. Kajiwara et al., Nature 464, 262 (2010).

Abstract: Hybrid organic-inorganic perovskites have been rediscovered recently as great absorbers in solar cells. In these materials the combination of organic and inorganic components leads to a material that is both low-cost, solution processable and an excellent, crystalline semiconductor. Particularly the solar cell efficiency, now close to 20%, has triggered a huge research activity on otherwise rather conventional devices. In this short talk I will try to answer what is the origin of the unique properties of halide perovskites?

Dodatkowe informacje: Dr Olga Malinkiewicz zajmuje się badaniami nad fotoogniwami perowskitowymi, będącymi od dwóch lat najbardziej obiecującym materiałem do konstrukcji nowej generacji baterii słonecznych. Podczas swojego pobytu na Uniwersytecie w Walencji dr Malinkiewicz odniosła spektakularny sukces, opracowując nową metodę wytwarzania fotoogniw perowskitowych na elastycznym podłożu i w niskich temperaturach. Odkrycie to, szeroko komentowane w polskich mediach,  zostało opublikowane w zeszłym roku w czasopiśmie Nature Photonics,  a sama autorka uzyskała za nie wiele prestiżowych wyróżnień dla młodych naukowców. Po powrocie do Polski dr Olga Malinkiewicz założyła firmę Saule Technologies, której celem jest komercjalizacja elastycznych fotoogniw perowskitowych. Przyjazd dr Olgi Malinkiewicz do Poznańia jest związany z planami współpracy z grupą zajmującą się badaniami fotowoltaicznymi na Wydziale Fizyki UAM. Dr Malinkiewicz poszukuje także młodych, zdolnych osób do prowadzenia badań nad wytwarzaniem fotoogniw perwoskitowych, dlatego w szczególny sposób zapraszamy na seminarium studentów oraz doktorantów z fizyki i chemii.

Abstract: In the intention of its creator, Maxwell’s demon was thought to be an intelligent being, able to perform work at the expense of the entropy reduction of a closed operating system. The perplexing notion of the demon’s intelligence was formalized in terms of memory and information processing by Szilard and subsequent followers, who pointed out that, in order for the total system to obey the second law of thermodynamics, the entropy reduction should be compensated for by, at least, the same entropy increase, related to the demon’s information gain on the operating system’s state. A non-informational formulation of the problem was proposed by Smoluchowski and popularized by Feynman as the ratchet and pawl machine, which can operate only in agreement with the second law. A. F. Huxley and consequent followers adopted this way of thinking to suggest numerous thermal ratchet mechanisms for the protein molecular machines’ action, but no entropy reduction takes place for these models. More general models of protein dynamics have been put forward with a number of intramolecular states organized in a network of stochastic transitions. Here, the computer model of such a network is investigated, displaying, like networks of the systems biology, a transition from the fractal organization on a small length-scale to the small-world organization on the large length-scale. This model, when allowing work performance in a variety of ways, obeys the generalized fluctuation theorem with entropy reduction and is able to explain a surprising observation to Yanagida and co-workers that the myosin II head can take several steps along the actin filament per ATP molecule hydrolysed. From a broader perspective, the supposition that (i) a similar mechanism of action is characteristic for most intrinsically disordered proteins and (ii) this is the reason for most protein machines to operate as dimers or higher organized structures could be of especial importance.

Abstract: This work presents the results of kinetic measurements of the Au(III) chloride complex ions reduction with hydrazine and of the gold nanoparticles formation in aqueous solution and in microemulsion system of H₂O/CTAB/alcohol/hexane. The dynamics of the gold nanoparticles formation in aqueous solution was studied using UV-Vis spectrophotometry, DLS and TEM methods. Nucleation and autocatalytic growth rate constants were determined by using the modified Finke Watzky model. The TEM measurements and hydrodynamic radius time evolution have revealed that the nanoparticles are unstable and grow until they reach a submicron size. The growth is triggered by the autocatalytic reduction of Au(I) ions on the surface of the growing particle and aggregation followed by chemical reaction limited by the Ostwald repining. Stabilization of gold nanoparticles can be provided by conducting their synthesis in reverse micelles. During the synthesis micelles act as nanoreactors and soft templates for the growing particles. The influence of the molar ratios: w = n_H2O:n_CTAB and p = n_alc:n_CTAB of the Au(III) ion initial concentration and the presence of different alcohols (butanol, pentanol, hexanol or heptanol) as cosurfactants on the formation kinetics and the nanoparticle morphology were studied. The particles with the smallest polydispersity are formed at a low Au(III) ion concentration and at for low w parameter or in the presence of alcohols with longer hydrocarbon chain. The particle growth is limited by the diffusion of the monomers between the micelles, which can be caused by a low Au(III) ion occupancy per a single micelle and/or a slow intermicellar exchange rate.

Abstract: Przedstawiony zostanie wpływ promieniowania jonizującego na tkankę biologiczną i jego wykorzystanie w podstawowej radioterapii nowotworów. Omówione będą sposoby generowania strumienia protonów oraz zalety i wady zastosowania wiązki protonów w leczeniu nowotworów. Pokazane zostaną przykłady ośrodków medycznych w Szwajcarii, Niemczech i Polsce stosujących w praktyce klinicznej terapię protonową. Zaprezentowane zostaną własne wstępne wyniki badań wpływu wiązki protonowej na nanoleki stosowane w terapii nowotworów.

Abstract: Whenever the value of an unknown parameter θ is extracted from a series of experiments, the result is inevitably burdened by the uncertainty ∆θ. If the system, which is the subject of measurement consists of unentangled particles, this uncertainty is bounded by the shot-noise limit. To overcome this limitation, it is necessary to use a properly entangled state, which is usually prepared in a dedicated procedure. We show that quantum correlations arising from the indistinguishability of bosons are a sufficient resource for the sub-shot-noise interferometry. To this end, we consider an interferometer, which operates on two independently prepared Bose-Einstein condensates with fluctuating numbers of particles. We calculate the sensitivity obtained from the measurement of the number of atoms and compare it with the ultimate achievable bound. Our main conclusion is that even in presence of major atom number fluctuations, an interferometer operating on two independent condensates can give very high precision. These observations indicate a new possibility for an interferometer operating below the shot-noise limit.

Abstract: In my presentation I will mention transport properties of two quantum dots, coupled to two leads in, so called, T-shaped configuration. This mean, that one of the dots is embedded between the leads, while the second is not directly coupled to the leads, but coupled to the first dot. We restrict ourselves to the linear response regime. Nevertheless, the physics of such a system is still very reach and includes the two-stage Kondo effect (the conductance is enhanced below the Kondo temperature, but becomes suppressed at even lower temperatures) and Fano-like interference effects, resulting in a sharp dip in the conductance vs. gate voltage dependence. Moreover, both effects are strongly influenced by the presence of magnetism: either in the form of magnetic field, or encapsulated in ferromagnetic leads. In particular, the second stage of the Kondo effect can be suppressed (that is, the usual Kondo effect restored), and a perfect spin polarization of the conductance can be obtained due to the spin-dependent Fano anti-resonance condition. I will explain these effects, with stress put on the case of ferromagnetic leads (results were obtained with I. Weymann, ZFMezo, UAM). To resolve properly all the many-body correlations, we employed the Numerical Renormalization Group method.

Abstract: This talk will be devoted to physics research and facilities at Nanyang Technological University (NTU) in Singapore and stipends it offers to undergraduate students (internships) and PhD students. I hope this will be of interest to faculty members who would like to collaborate with Singapore’s scientists as well as students who would like to pursue their postgraduate career at NTU.

Abstract: With growing evidence of quantum effects in more and more complex systems it becomes legitimate to ask if alive matter can be influenced or take advantage of quantum features. Such questions are studied in a newly emerging field of quantum biology. Two examples will be discussed in more detail where quantum coherence may play a role to speed up biologically relevant process (photosynthesis) or even enable it (magneto-reception). Finally, I will describe our planned experiments on insects and how they are related to quantum biology.

Abstract: During the past two decades thin film photovoltaic cells based on solution processable organic semiconductors attracted much attention as possible cheap energy harvesting systems. They are envisaged as feasible alternative to conventional inorganic technologies. One great advantage of the organic photovoltaic is that their morphological and photophysical properties can be easily modified by tailoring the molecular structure. Therefore, a great effort is made for the synthesis and characterization of new organic materials, small molecules and polymers. Another big advantage of the organic semiconductors is their mechanical flexibility. Optimisation of the polymer molecules from the fundamental core of this push-pull polymer have since gone on to produce single junction organic photovoltaic device with power conversion efficiency of 9%. The rapid increase in the light harvesting efficiency was also followed by the approaches in using solar energy for application in chemical reduction. Here, a particularly interesting approach is to use solar energy for the chemical and electrochemical reduction of CO₂ to hydrocarbons as well as for the artificial photosynthesis.

Abstract: Phthalocyanines and porphyrins find nowadays a variety of applications from pigments to organic electronics and, more recently, spintronics. This diversity of application potential stems from the large flexibility of their molecular structure. We focus on the room temperature magneto-optical activity of phthalocyanines and porphyrins deposited on ferromagnetic substrates (Co, Ni, and LSMO) as model heterostructures for organic spintronics. The magnetic properties of the heterostructures are assessed by magneto-optical Kerr effect (MOKE) magnetometry. Variable angle spectroscopic ellipsometry (VASE) in combination with MOKE spectroscopy investigations are performed to extract the (magneto-) optical properties of the heterostructures. From the degree of anisotropy of the optical constants the molecular orientation can be determined. This allows to systematically investigate the influence of the substrate magnetization direction onto the molecular arrangement.

Abstract: I am presenting the results of investigation of spin wave properties in periodic ferromagnetic structures (one-dimensional magnonic crystals). The main attention of research was put on development of numerical methods and analysis of spin waves properties that are important for designing a functional device. Three subjects of spin waves properties were studied and they can be classified as: i) influence of damping on standing spin wave formation ii) metamaterial properties for electromagnetic waves propagating through magnonic crystal and iii) nonreciprocal dispersion of spin waves. In particular I have shown the analysis of the influence of the damping factor on the spectrum of ferromagnetic resonance, the influence of metallic overlayer on the damping, influence of structural parameters of magnonic crystals on the magnetic permeability function of metamaterial based on the crystal. I have also presented a detailed analysis of symmetry breaking of the dispersion relation of spin waves propagating in the ferromagnetic films in contact with metal. The numerical calculation were confronted with measured data, when available, and agreement between them was shown.

Abstract: Studies on the phonon engineering have been gaining importance in recent 20 yr. Previous research has shown that phonon dispersion relation can be significantly modified by means of phononic crystals (PnCs) [1-3], spatial confinement [4-5], or external stress field [6-7]. Phononic crystals are in general materials with one- (1D), two-, or three-dimensional periodicity in their elastic properties. PnCs exhibit the modification of the phonon dispersion and possible complete frequency band gaps due to Bragg reflections or/and local resonances, which can be controlled by geometry and material properties. Another approach to modify the phonon dispersion relies on spatial confinement. Here, the dynamic behaviour at reduced characteristic dimensions has been found to be completely different than for bulk materials. I will report on experimental (Brillouin light scattering) and theoretical (finite element method) evidence of both phononic properties (zone folding, band gap and local resonance) and phonon confinement in one-dimensional Si surface PnCs and two-dimensional Si membrane based PnCs. Additionally, I will discuss the influence of the phononic patterning and phonon confinement on thermal properties (Raman thermometry) and potential applications of PnCs in thermoelectric devices. [1] N. Gomopoulos, D. Maschke, C. Y. Koh, E. L. Thomas, W. Tremel, H.-J. Butt, and G. Fytas, Nano Lett. 10, 980 (2010).
[2] B. Graczykowski, S. Mielcarek, A. Trzaskowska, J. Sarkar, P. Hakonen, and B. Mroz, Phys. Rev. B 86, 085426 (2012).
[3] B. Graczykowski, M. Śledzińska, N. Kehagias, F. Alzina, J. S. Reparaz, C. M. Sotomayor Torres, APL 104, 123108 (2014).
[4] V. A. Fonoberov and A. A. Balandin, Nano Lett. 5, 1920 (2005).
[5] J. Cuffe, E. Chvez, A. Shchepetov, P.-O. Chapuis, E. H. El Boudouti, F. Alzina, T. Kehoe, J. Gomis-Bresco, D. Dudek, Y. Pennec, B. Djafari-Rouhani, M. Prunnila, J. Ahopelto, and C. M. Sotomayor Torres, Nano Lett. 12, 3569 (2012).
[6] A. Alofi and G. P. Srivastava, Phys. Rev. B 87, 115421 (2013).
[7] B. Graczykowski, J. Gomis-Bresco, F. Alzina, J. S. Reparaz, A. Shchepetov, M. Prunnila, J. Ahopelto, C.M. Sotomayor Torres, New J. Phys. 16, 073024 (2014).

Abstract: Damaging effects of synchrotron radiation were observed for the wide range of biological samples, ranging from protein crystals to biological cells and tissues [1,2]. Most often these damages were manifested as radiolysis of the tested molecules. However, so far were not observed any conformational changes (such as domain swapping) in the protein structures induced by the synchrotron radiation. The aim of this study was to observe the early stages of dimerization of human cystatin C (HCC) via the domain swapping mechanism. The time-resolved small angle scattering experiments were performed using synchrotron radiation on P12 BioSAXS beam line with very short acquisition time (50 ms) at PETRA III synchrotron (DESY Hamburg). Solution scattering data were subjected to detailed analysis by using SVD methods and MCR-ALS as well as the shape determination. Besides the monomeric forms of human cystatin C, also fractions of dimers and higher oligomeric forms of HCC formed even after 50-ms exposure were identified. In addition we showed directly for first time that the formation of human cystatin C oligomers and fibryls was directly preceded by the formation of domain swapped dimer. [1] Borek, D.; Dauter, Z.; Otwinowski, Z. (2013) J. Synchr. Rad. 20, 37-48.
[2] Chen, Heyu; He, Xin; Sheng, Caibin; Ma, Yingxin; Nie, Hui; Xia, Weiliang; Ying, Weihai (2011) Int. J. Physiol. Patophysiol. Pharmacol. 3, 243-248.

Abstract: Toxic hydrophobic drugs can be delivered to cancer tissue using benign nano-sized carriers made of block copolymers, dendrimers, or dendrimer-in-liposome particles. Polymeric carriers prepared via micellization in non-aqueous near-critical solvents, referred to as Near-Critical Micellization, have been demonstrated to lead to a much higher drug loading, by as much as a factor of three and to inhibit its premature release. This will be illustrated with examples for PEG-b-PLLA-b-PCL nanoparticles loaded with a model cancer drug paclitaxel. Such triblock nanoparticles are found to be not only solvent-free and paclitaxel-rich, which reduces the body exposure to the excipients, but also nearly burst-release-free, which enhances their therapeutic efficacy. Dendrimer-in-liposome carriers, in turn, provide a unique opportunity to address two other, seemingly contradictory drug-delivery requirements, namely a large size and hence good stability while in circulation but small size and hence rapid diffusion while penetrating the tumor tissue.

Abstract: We discuss a model with ultra-cold atoms confined in optical superlattices. In particular, we study the ground-state properties of our system. Applying model involving spin-1 bosons trapped in a double-well potential, we quantify the bipartite entanglement between particles. Depending on the external magnetic field and biquadratic interactions different phases of magnetic order are realized and hence, various phases of the system’s entanglement. We show that changing the values of the parameters determining superlattices, we can switch the system among various maximally entangled states. What is important, our model seems to be a good candidate for practical realization of the device which can be a switchable tool for generation on demand of such a states. [1] A. Barasiński, W. Leoński, T. Sowiński, to appear in JOSA B (2014).

Abstract: The influence of substrate ferroelastic phase transition on the magnetization of ferromagnetic thin film was investigated. Two different ferroic materials have been used: ferroelastic/ferroelectric Gd₂(MoO₄)₂ and pure ferroelastic LiCsSO₄ as a substrates. A nickel and permalloy thin films, with the different thickness from 10 to 100 nm were used. Our measurements showed strong magnetization change at Curie point, which reflect the temperature changes of spontaneous deformation of the samples. A strain-driven spin reorientation transitions were described theoretically using a magnetic domain theory. It was shown that magnetization reorientations occurs due to magnetoelastic contribution to free energy and thus affect total magnetization value of a sample. Results of our simulations were found to be in good agreement with the experiments. The preliminary results of Brillouin scattering on spin waves propagating in our samples will be shown.

Abstract: Protein-protein interactions drive many of the biological functions of the cell. Any two proteins have the potential to interact; however, whether the interactions are of biological significance is dependent on a number of complicated factors. Thus, modelling the three-dimensional structure of protein-protein complexes is still considered to be a complex endeavour. In addition to correct protein-protein complex 3D structure returned by the algorithm, equally important is dynamics of binding, i.e., how proteins find their binding partners in the multidimensional space of conformational transitions and how their binding partners, upon complex formation, sample binding funnels, i.e. what is the structure of conformational states space and in which manner proteins change their conformations when traversing this network. We recently released two freely available tools: SwarmDock Server (a web service for the flexible modelling of protein-protein complexes) [1] and RaTrav (a tool for calculating mean first-passage times) [2]. In this talk we share our experience related to conformational state network generation, its structure and dynamics. We successfully applied occupancy probabilities to distinguish between false positive and true positive protein-protein binding funnels [3]and mean first-passage times to find the favourable path and limiting transitions in the true positive protein-protein binding funnel [2]. [1] M. Torchala, I.H. Moal, R.A.G. Chaleil, J. Fernandez-Recio, P.A. Bates, ‘SwarmDock: a server for flexible protein-protein docking’, Bioinformatics 29, 807-809 (2013).
[2] M. Torchala, P. Chelminiak, M. Kurzynski, P.A. Bates, ‘RaTrav: a tool for calculating mean first-passage times on biochemical networks’, BMC Syst. Biol. 7, 130 (2013).
[3] M. Torchala, I.H. Moal, R.A.G. Chaleil, R. Agius, P.A. Bates, ‘A Markov-chain model description of binding funnels to enhance the ranking of docked solutions’, Proteins: Structure, Function, and Bioinformatics 81, 2143-2149 (2013).

Abstract: I study operation of realistic elementary quantum repeater links constructed using multiple single photon sources, quantum memories, linear optics, and heralding detectors. Two schemes are considered. The first one is the well established one-photon scheme which produces a photon in a delocalized superposition state between two quantum repeater nodes, each of them fed with one single photon at the input. The second one is a linear optics analog of the robust scheme based on interfering two Stokes photons emitted by atomic ensembles, which does not require phase stability between the repeater nodes. Imperfect photon sources are assumed, generating outputs with both vacuum and multiphoton contributions. I find conditions for the source photon statistics that guarantee generation of entanglement in the relevant qubit subspaces and compare it with classicality criteria. I also quantify the amount of entanglement that can be produced with imperfect single photon sources, optimized over setup parameters, using as a measure entanglement of formation. Finally, I discuss verification of the generated entanglement by testing Bell’s inequalities.

Abstract: At the macro-scale the extent to which a liquid wets a solid substrate is usually described in terms of the contact angle, θ_c, and the surface tensions involved. Depending on the liquid and substrate, the system is described as amphiphilic (‘wetting’, θ_c < 90^o) or amphiphobic (‘non-wetting’, θ_c > 90^o). Such a description has a number of limitations; in particular, it breaks down for sufficiently small nano-scale systems, and is limited to describing liquid, as opposed to gaseous or solid, adsorbed films. At a more fundamental level, wetting is determined by the competition between the adsorbate-substrate intermolecular forces and the adsorbate-adsorbate forces. Through a corresponding states analysis of the statistical mechanical description of such wetting systems it is possible to define a microscopic wetting parameter, a_w, that is a measure of wetting that applies at all scales and for any kind of adsorbed film (gas, liquid or solid) [1,2]. We illustrate the usefulness of this wetting parameter by considering the properties of a nano-phase confined within a porous material. In this case the dimensionless pore width, pore shape and wetting characteristics of the confined phase are of particular importance. Examples drawn from both experiment and molecular simulation studies will be presented for phase separations, selective adsorption in the case of mixtures, and pressure enhancement, with emphasis on simple pore geometries. These examples illustrate the central role played by wetting, and also the breakdown of some concepts and macroscopic laws, such as Gibbs’ surface thermodynamics for nano-phases confined within small pores. [1] R. Radhakrishnan, K.E. Gubbins and M. Śliwińska-Bartkowiak, “Global Phase Diagrams for Freezing in Porous Media”, Journal of Chemical Physics, 116, 1147-1155 (2002).
[2] Keith E. Gubbins, Yun Long and Małgorzata Śliwińska-Bartkowiak, “Thermodynamics of Confined Nano-Phases”, Journal of Chemical Thermodynamics, 74, 169-183 (2014).

Abstract: It is well known, that exact Bethe Ansatz solutions for the Heisenberg eigenproblem of a linear magnetic chain base upon the hypothesis of strings. This hypothesis is presumed to work in the thermodynamic limit N→∞, but it works pretty well also in the finite case. I present some details of analysis performed for short magnetic chains. In particular, I exploit Galois symmetry associated with the secular eigenproblem in determining rigged string configurations.

Abstract: I present a general scheme for encoding and decoding an unknown qubit state into various topological codes for quantum error correction. I illustrate this method by means of Kitaev planar code, where qubits are arranged in a two-dimensional array on a surface of nontrivial topology. I also show that in the noisy scenario (when state preparation and measurements are faulty) an analytical bound for the fidelity of a quantum communication can be easily provided following the scheme and is of order of noise acting on a single physical qubit, in a large code size limit.

Abstract: Protecting quantum information from errors due to decoherence and other quantum noise is crucial for fault-tolerant quantum computation. In order to do quantum information processing reliably in the presence of noise, the theory of error-correcting codes has been developed. These codes work by encoding quantum states in a special way that make them resilient against the effects of noise, and then decoding when it is wished to recover the original state. I start my presentation with comprehensive introduction to quantum error correction theory. Then, I carry on with short description of topological quantum error-correcting codes, an important class of quantum codes.

Abstract: With conventional CMOS technology data is carried by flows of electrons that generate heat which is responsible for the device’s power consumption. An alternative to this principle is the employment of other particles or quasi-particles as information carriers which are subject to dissipation to a lesser degree than electrons. I will show that eigen excitations of magnetic media – magnons can be used for this role. In my talk, after an introduction on spin waves and their quanta magnons, I will concentrate on the artificial magnetic materials with periodically-modulated magnetic properties – magnonic crystals. Several different designs of macro- and micro-scaled magnonic crystals will be discussed [1-3]. In the second part of the talk, the magnon-based data processing elements will be shown: time reverser of microwave pulses [4] and magnon transistor. These proof of concept devices are made out of an insulator in order to exclude any motion of free electrons and are based on magnonic crystals. The time reverser is based on a dynamic magnonic crystal: a crystal with properties that can be varied using external controls on a very fast time scale. We have shown that a wave packet, while being reflected by the dynamic crystal, reverses its time profile [4]. The magnon transistor is the device operational principle of which is based on the control of magnons by magnons. It was realized through an enhancement of nonlinear magnon interactions in a magnonic crystal. We have shown that the transistor allows for the design of all-magnon logic gates as well as for enhancement of magnonic signals. The final part of the talk will be devoted to the miniaturization issues of the insulator-based magnonics. Very recently we have studied spin-wave excitation and propagation in an insulator yttrium-iron-garnet spin-wave waveguide of micrometer sizes [5]. These results represent a valid step towards the nano-scaled particle-less technology in which information is carried and processed by magnons rather than by electrons. [1] A.V. Chumak, et al., Phys. Rev. Lett. 108, 257207 (2012).
[2] A.V. Chumak, et al., Appl. Phys. Lett. 95, 262508 (2009).
[3] B. Obry, et al., Appl. Phys. Lett. 102, 202403 (2013).
[4] A.V. Chumak, et al., Nat. Commun. 1:141 doi: 10.1038/ncomms1142 (2010).
[5] P. Pirro, et al., Appl. Phys. Lett. 104, 012402 (2014).

Abstract: A procedure to obtain the expectation value of an arbitrary observable is referred to as “state.” Usually, such “state” has one-to-one correspondence to the quantum state of the physical system. In some cases, however, we know not only the prepared quantum state but also the post-selected state, which we actually see. If we estimate the measurement result performed by the third party intermediately, such mathematical “state” contains two physical states: initial and final states. Sometimes, we can precisely estimate the value of the conjugate observables regardless with his/her choice [1]. The “state” of course depends on the measurement, but the expression becomes simple for the weak measurement and strong measurement. For the weak measurement, it becomes the weak value [2], which exhibits interesting properties in paradoxical situations [3,4]. [1] K. Shimizu, et. al.: Phys. Rev. A 84, 022308 (2011).
[2] Y. Aharonov, et. al.: Phys. Rev. Lett. 60, 1351 (1988).
[3] Y. Aharonov, et. al.: Phys. Lett. A 301, 130 (2002).
[4] J. S. Lundeen and A. M. Steinberg, Phys. Rev. Lett. 102, 020404 (2009);
    K. Yokota et. al., New J. Phys. 11, 033011 (2009).

Abstract: Heusler alloys are a class of materials with diverse physical properties and many potential applications. Depending on their specific composition they can exhibit half-metallic ferromagnetism (full spin polarization at the Fermi level), magnetic shape memory (martensitic transformation in a ferromagnetic state), among others. The Heusler alloys Ni-Mn-Sn belong to a family of magnetic shape memory alloys. This magnetostructural transformation leads to magnetocaloric effect, modification of exchange coupling, large magnetoresistance, etc. The comprehensive experimental investigation of magnetic, transport and structural properties of Ni-Mn-Sn thin films was undertaken as well as ab initio calculations. It was shown that the local atomic configuration affects on magnetic properties. The estimated values of the martensitic transformation temperature and Curie (Néel) temperature were collected in the form of phase diagram.

Abstract: Z chwilą, gdy rozwinęły się badania nad przyczyną chorób wywołanych przez amyloidy, rozbudowane zostały również badania podstawowe dotyczące procesu agregacji białek. Wykazano szybko, że proces agregacji występuje stosunkowo często i generalnie może to być proces odwracalny (w niektórych przypadkach in vivo) lub nieodwracalny (także w szczególnych przypadkach zmian fizjologicznych). Powstające agregaty mają często formę uporządkowanych, regularnych struktur. Wykazano także, że proces agregacji ściśle wiąże się z denaturacją cząsteczek białkowych.

Abstract: Heusler alloys are a class of materials with diverse physical properties and many potential applications. Depending on their specific composition they can exhibit half-metallic ferromagnetism (full spin polarization at the Fermi level), magnetic shape memory (martensitic transformation in a ferromagnetic state), among others. The Heusler alloys Ni-Mn-Sn belong to a family of magnetic shape memory alloys. This magnetostructural transformation leads to magnetocaloric effect, modification of exchange coupling, large magnetoresistance, etc. The comprehensive experimental investigation of magnetic, transport and structural properties of Ni-Mn-Sn thin films was undertaken as well as ab initio calculations. It was shown that the local atomic configuration affects on magnetic properties. The estimated values of the martensitic transformation temperature and Curie (Néel) temperature were collected in the form of phase diagram.

Abstract: I will discuss two issues related to the performance of artificial and biological engines. Three cases will be presented: ferroelectric liquid crystal monolayer performing continuous rotation in a monolayer of 3nm size powered by the flux of water; ATP as a biological pump powered by the flux of protons and finally kinesin motion along microtubules. In these three cases we will discuss the power of such engines and their resistance to thermal noise and local energy barriers induced by crowding by linear polymers.

Abstract: We study the properties of neutral and charged dendrimers with flexible spacer-chains of various lengths and explicit counterions using Monte Carlo simulations based on the bond fluctuation model. For neutral dendrimers with the excluded volume interactions our simulations confirm the theoretical prediction for the scaling behavior of the dendrimer size. For charged dendrimers the full Coulomb potential is taken into account with the reduced temperature τ as the main control parameter. Our simulations show an interplay of counterion condensation, trapping of counterions inside the dendrimer’s volume and counterion evaporation into the solution which give rise to a non-monotonous electrostatic swelling of the molecule with τ. To explain the swelling effect we apply a Flory-type argument where both trapped but non-condensed counterions and uncompensated charges due to counterion evaporation are included. This model properly reflects the swelling behavior with respect to temperature, pH and spacer-length variation, though quantitatively underestimates it.

Abstract: Experimental techniques nowadays allow for detailed transport measurements of individual atoms [1] or molecules [2,3] that exhibit magnetic anisotropy. The superparamagnetism of these systems, i.e. the preferential alignment of their spins along an easy axis, is a useful effect for nanoscale applications as it prevents undesired spin reversal. It has been suggested [4], and also experimentally proven for magnetic atoms [5], that spin-polarized currents can be employed to control the magnetic state of such systems assuming a given, intrinsic anisotropy. Furthermore, it has been also demonstrated that magnetic anisotropy can play a major role in formation of the Kondo effect in nanoscopic systems [1,3]. However, the spintronic transport also changes the magnetic anisotropy that it tries to probe and therefore these two cannot be treated separately. In fact, we have recently shown that any spin-isotropic high-spin quantum dot coupled to ferromagnets can acquire superparamagnetic properties in a spintronic way, i.e. from the outside via an effective quadrupolar exchange field [6]. The talk will review various theoretical aspects of transport through nanoscopic systems displaying magnetic anisotropy, with the main emphasis on how the flow of spin-polarized current through such a molecule/adatom can induce the magnetic anisotropy. [1] A.F. Otte et al., Nature Phys. 4, 847 (2008).
[2] H.B. Heersche et al., Phys. Rev. Lett. 96, 206801 (2006); A. Zyazin et al., Nano Lett. 10, 3307 (2010); E. Burzuri et al., Phys. Rev. Lett. 109, 147203 (2012).
[3] J.J. Parks et al., Science 328, 1370 (2010).
[4] M. Misiorny and J. Barnaś, Phys. Rev. B 75, 134425 (2007); Phys. Rev. Lett. 111, 046603 (2013).
[5] S. Loth et al., Nature Phys. 6, 340 (2010).
[6] M. Misiorny, M. Hell and M. Wegewijs, Nature Phys. 9, 801 (2013).

Abstract: Magnetic nanoparticles have many applications, from printing to medical treatments, electronic memories and radio frequency devices, but their magnetic structure is still not well known. After a short review of one century of observations of magnetic domains in magnetic particles and magnetic nanoparticles especially on 2D particles, comments will be given on last twenty years of numerical simulations. A short review of the magnetic dynamics of such particles and nanoparticles will also be given. Then analytic considerations on magnetic structures of 2D and 3D nanoparticles will be reported as well as basic models for the magnetic structure of small enough nanoparticles. Finally recent numerical results on the magnetic structure of 2D and 3D nanoparticles and their dynamics will be given.

Abstract: The lecture contains the review of the experimental data about the biogenic magnetic nanoparticles (BMNs) in different organisms. The BMNs became the object of intensive research since 1975 when the BMNs were detected in magnetotactic bacteria (MTB) for the first time. The literature data about the proteins of the so-called magnetosome island of MTB will be represented concerning the process of biomineralization of BMNs. The physiological origin of BMNs, their possible functions in multi-cellular organisms and interrelation with the number of human diseases will be considered on the basis of the bioinformatics methods and magnetochemical effects.

Abstract: We demonstrate a phase-independent quantum amplifier of a polarization qubit which can outperform the heralded qubit amplifier [S. Kocsis et al., Nature Physics 9, 23 (2013)]. It employs the multi-functional cloner in 1 to 2 copying regime, capable of providing approximate copies of qubits given by various probability distributions, and is optimized for distributions with axial symmetry. The direct application of the proposed solution is possible in quantum technologies, doubling the range where quantum information is coherently broadcast. It also outperforms natural nonlinear amplifiers that use stimulated emission in bulk nonlinear materials. We consider the amplifier to be an important tool for amplifying quantum information sent via quantum channels with phase-independent damping.

Abstract: During the talk I will present modern techniques that allow to actively controlling the optical properties of a single optical element e.g. the lens focal length. First I will show widely used macroscopic devices, used for instance in astronomy, then emerging microscopic devices developed recently. Finally, I will present our efforts in the development of a flexible focal length device, whose operation is based on a new thermo-optical technique.

Abstract: A new and efficient algorithm for the mean-field approximation is presented, in which we do not need to solve explicitly the self-consistent condition. This algorithm is a modification of the Metropolis algorithm which is often used in Monte Carlo simulations.

Abstract: This study offers a new perspective on the spatial impacts generated by cities or urban agglomerations. These impacts can range from chaotic to fully ordered. We demonstrate that cities produce a wealth of gravitational attractors whose size and shape depend on the resistance of space emerging inter alia from transport friction costs. This finding offers original insights into the complex evolution of spatial systems and appears to be consistent with the principles of central place theory known from spatial sciences and geography. Our approach is dynamic in nature and forms a generalization of hierarchical principles in geographic space.

Abstract: W ramach wykładu zaprezentowana zostanie najnowsza wersja 2.1.1 środowiska Algorithms and Libraries for Physics Simulations (ALPS) [1] wraz z jego zastosowaniami. ALPS jest projektem typu open source rozwijanym od roku 2004 przez międzynarodową grupę fizyków teoretyków specjalizujących się w badaniu układów silnie skorelowanych [2]. Wszystkie elementy pakietu wykorzystują wspólny format danych zapisanych w języku XML. Na tym poziomie przeprowadzenie symulacji nie wymaga znajomości programowania w języku C++, w jakim zostały napisane biblioteki obliczeniowe i główne aplikacje. Gotowe programy obejmują implementacje najważniejszych algorytmów dla modeli kwantowych na sieci, jak np.: klasyczne i kwantowe Monte Carlo (spinMC, QMC) w wersji lokalnej i klasterowej, kwantowe symulacje typu Wanga-Landaua (QWL), dokładna i pełne diagonalizacja (ED), macierz gęstości grupy renormalizacji (DMRG) czy dynamiczne pole średnie (DMFT). Zawarte w projekcie biblioteki stanowią ramy do rozwoju własnego oprogramowania z wykorzystaniem obliczeń równoległych typu openMPI na różnych platformach sprzętowych i systemowych. W nowej wersji 2 oprogramowania ALPS uwzględniono wykorzystanie standardu HDF5 do zapisu i zarządzania danymi, użycie specjalistycznych narządzi do analizy wyników napisanych w języku Python oraz integrację pracy całego systemu w środowisku do wizualizacji procesów obliczeniowych VisTrails. Wykład uzupełniony będzie o liczne przykładowe obliczenia. [1] http://alps.comp-phys.org;
[2] B.Bauer et al. (ALPS collaboration), “The ALPS project release 2.0: open source software for strongly correlated systems”, J.Stat.Mech. P05001 (2011).

Abstract: Przedstawione zostaną wybrane efekty zachowania się fal spinowych w strukturyzowanych warstwach granatu itrowo-żelazowego. Omówione będzie oddziaływania fal spinowych z: (i) pojedynczym otworem – zjawisko dyfrakcji fal spinowych; (ii) linią otworów – efekt całkowitego wewnętrznego odbicia tych fal; (iii) dwuwymiarową sieci otworów. Badania wykonano z wykorzystaniem: (i) klasycznego spektrometru nieelastycznego rozpraszania światła Brillouina (BLS) z rozdzielczością czasową i przestrzenną w konfiguracji odbiciowej i transmisyjnej, (ii) mikroskopu BLS pracującego w konfiguracji odbiciowej z rozdzielczością przestrzenną do ok. 300 nm; (iii) spektrometru FMR. Wyniki eksperymentalne interpretowano korzystając między innymi z modelowania mikromagnetycznego. Dodatkowo przedstawione będą, planowane do dalszych badań, nowe struktury magnoniczne w oparciu o naświetlane jonami magnetyczne nanostruktury.

Abstract: We study an application of an information-theoretic distance between two measurements to investigate non-classical correlations. We postulate the triangle principle, which states that any information-theoretic distance is well defined on any pair of measurements, even if these measurements cannot be jointly performed. As a consequence, the triangle inequality for this distance is obeyed for any three measurements. This simple principle is valid in any classical realistic theory, however it may not hold in quantum theory. It leads to derivation of certain inequalities whose violations are indicators of non-classicality. Some of these inequalities formally look the same as those found in the literature on local realism and non-contextuality but we also derive completely new inequalities. We also show that our geometrical approach naturally implies monogamy of non-classical correlations.

Abstract: My talk will consist of two parts. First, we propose a test to measure the bosonic and fermionic quality of particles with respect to physical operations of single-particle addition and subtraction. We apply our test to investigate bosonic properties of composite particles made of an even number of fermions and suggest its experimental implementation. Next, we show that under certain assumptions one can derive a variant of Specker’s non-contextual inequality for a system of three indistinguishable bosonic particles. The inequality states that the sum of probabilities of three pairwise exclusive events is bounded by one. This inequality cannot be violated using standard quantum mechanical projectors and cannot be violated by independent distinguishable particles. On the other hand, due to bosonic properties this bound is violated up to 3/2. We also argue that the violation of this inequality can be considered as a test of bosonic nature.

Abstract: In the preceding talk, prof. Adam Patkowski explained the methods and tools which have been used to calculate the pair correlation function g(r) and the structure factor S(q) of colloidal systems with Yukawa-type interactions. Using these tools we managed to calculate the freezing lines of such systems both using experimentally measurable parameters and generalized parameters. In the latter case a master curve was obtained. In this part I am going to discuss the information accessible from the pair correlation function g(r) which describes the local structure of colloidal systems. In particular, I will show such parameters as the number of nearest neighbors, mean nearest neighbor distance, position of the maximum of g(r), and peak position of S(q). Conclusions drawn from the values obtained at freezing lines will be extended to colloidal systems in fluid state, leading to surprising results concerning the local structure of strongly interacting colloids.

Abstract: Oddziaływania w zawiesinach naładowanych koloidów opisane są przez efektywną energię oddziaływań dwójkowych typu Yukawy: u(r)/k_BT ∼ AZ²exp(−κr)/r, gdzie A jest stałą układu, κ⁻¹ – długością ekranowania Debye’a, Z – efektywnym ładunkiem cząstki. Uporządkowanie bliskiego zasięgu w układach koloidalnych może być mierzone przy pomocy: dwójkowej funkcji rozkładu radialnego g(r), średniej odległości najbliższych sąsiadów r_n i ich liczby N_n. Ostatnie dwie wielkości mogą być obliczone z funkcji g(r). Uporządkowanie dalekiego zasięgu w układach koloidalnych mierzone jest przez zależny od wektora rozpraszania q statyczny czynnik struktury S(q), który może być zmierzony w eksperymencie rozpraszania światła lub nisko-kątowego rozpraszania promieni rentgena (SAXS). Punkt krystalizacji układu koloidalnego dany jest przez kryterium Hansena-Verleta (HV): S(q_m)=3. Dynamika układu koloidalnego charakteryzowana jest przez krótko-czasowy współczynnik dyfuzji kolektywnej D_C(q), określony jako: D_C(q)=D₀H(q)/S(q), gdzie D₀ jest wartością dla nieskończonego rozcieńczenia układu, a H(q) jest zależną od q funkcją hydrodynamiczną. Wykazaliśmy, przy pomocy statycznego (SAXS) i dynamicznego (XPCS) rozpraszania rentgenowskiego promieniowania synchrotronowego, że modele teoretyczne dla S(q) – równanie całkowe Rogersa-Younga (RY), oraz dla D_C(q)-model δγ, dobrze opisują dane doświadczalne uzyskane dla naładowanych koloidów w całym zakresie ciekłym [1]. Stosując model δγ przeanalizowaliśmy zachowanie funkcji hydrodynamicznej H(q) [2], a przy pomocy równania całkowego RY oraz kryterium HV uzyskaliśmy również krzywą krystalizacji [3] dla naładowanych koloidów typu Yukawy w szerokim zakresie ładunku, rozmiarów i stężenia koloidów i stężenia dodanej soli. Ostatnio badaliśmy także punktu krystalizacji. [1] J. Gapinski, A. Patkowski, A. J. Banchio, J. Buitenhuis, P. Holmquist, M. P. Lettinga, G. Meier and G. Nägele, J. Chem. Phys. 130 (2009) 084503.
[2] J. Gapinski, A. Patkowski and G. Nägele, J. Chem. Phys. 132 (2010) 054510.
[3] J. Gapinski, G. Nägele, and A. Patkowski, J. Chem. Phys. 136 (2012) 024507.

Abstract: The properties of small magnetic dots are the object of increased interest because of their rich physics and potential applications in a variety of fields, such as data storage and information processing, single magnetic nanoparticle sensing and trapping, microwave-frequency oscillators, or frequency multiplication. The physical phenomena observed in small magnetic dots are related to their minute dimensions, ranging from tens of nanometers to a few micrometers, and the competition between the long-range dipolar interaction and the short-range exchange interaction. In small magnetic dots their concurrence leads, among other effects, to a rich spectrum of stable and metastable magnetic configurations, including vortex states. The chirality and polarity of the vortex are potential information carriers and can be switched with external magnetic field, electric current, or microwave radiation. An important role in magnetization switching, as well as in the stability of magnetic configurations, is played by spin-wave excitations. Moreover, the role of thermally excited spin waves in magnetization switching proves very important even in particles smaller than the exchange length. In this work we use a microscopic theory taking into account the dipolar and nearest-neighbour exchange interactions for exploring spin-wave excitations in two-dimensional magnetic dots in the vortex state. Normal modes of different profiles are observed: azimuthal and radial modes, as well as fundamental (quasiuniform) and highly localized modes. We examine the dependence of the frequencies and profiles of these modes on the dipolar-to-exchange interaction ratio and the size of the dot. Special attention is paid to some particular modes, including the lowest mode in the spectrum and the evolution of its profile, and the fundamental mode, the frequency of which proves almost independent of the dipolar-to-exchange interaction ratio. Finally, we study the hybridization of the modes, show the multi-mode hybridization and explain the selection rules. [1] S. Mamica et al., J. Phys. D, accepted (2013).
[2] S. Mamica, J. Appl. Phys., accepted (2014).

Abstract: The properties of polymer films formed by adsorbed or tethered chains are important for practical reasons (lubrication, colloidal stabilization, chromatography etc.) and interesting from the theoretical point of view. The adsorption of homo- and copolymers on homogenous and patterned surfaces was a subject of our studies. We employed computer simulations of idealized models as a main tool. The coarse-grained models of macromolecules were designed for this purpose. The properties of the system studied were determined using some versions of the Monte Carlo method. The influence of the temperature, the strength of the adsorption, the sequence of mers, patterns on the surface and the macromolecular architecture on the properties of chains were studied. The results were discussed and compared to other simulations results, theoretical predictions and real experiments.

Abstract: A major scientific interest of magnetic nanodots and nanorings lies in the concurrence of the exchange and dipolar interactions. In a variety of systems, long-range interactions have led to a number of interesting findings. However, the concurrence of short-range and long-range interactions proves particularly interesting. Also the magnetic vortex state stems from the competition between the long-range dipolar interaction and the short-range exchange interaction. On the other hand, studies of the possible stable and metastable magnetic configurations in magnetic nanorings are of major importance regarding to the potential applications which extend from data processing and high-density magnetic random access memory (MRAM) elements to microwave frequency oscillators and single magnetic nanoparticle sensors. In this work we study two-dimensional nanodots and nanorings composed of elementary magnetic moments arranged in sites of a square lattice. Using a microscopic approach that takes into account the dipolar and nearest-neighbour exchange interactions, we calculate the spin-wave frequencies and profiles to draw conclusions regarding the stability of the assumed magnetic configuration. We show that, in contrast to square rings, in circular rings the exchange-driven reorientation is sensitive to both the external and internal sizes of the ring. We associate this behaviour with the delocalized character of the lowest spin-wave excitation, and show that, consequently, the in-plane vortex state can be stabilized even in the case of strong exchange interactions. [1] S. Mamica et al., J. Nanopart. Res. 13, 6075 (2011).
[2] S. Mamica et al., J. Appl. Phys. 112, 043901 (2012).
[3] S. Mamica, J. Appl. Phys. 113, 093901 (2013).

Abstract: Struktura białek od dziesięcioleci stanowi przedmiot dociekań naukowców z różnych dziedzin. Dzięki znajomości przestrzennej budowy cząsteczek biologicznych łatwiej jest przewidzieć i zrozumieć ich funkcję. We współczesnej farmacji rozwiązanie struktury tak zwanego białka docelowego (targetu) jest podstawą zaprojektowania skutecznego i specyficznie działającego leku. Rozwinięto zatem wysokorozdzielcze techniki eksperymentalne pozwalające z dokładnością do pojedynczego atomu określić przestrzenne rozmieszczenie wszystkich jego elementów. Na tej podstawie powstała hipoteza o uporządkowanej i stosunkowo sztywnej budowie białek. Okazało się jednak, że pośród białek, którym przypisano kluczową rolę w procesach biologicznych wiele posiada budowę „wewnętrznie nieuporządkowaną”. Struktura białka zdenaturowanego (rozplecionego w określonych warunkach), podobnie jak struktura giętkich nieuporządkowanych wewnętrznie białek, nie może być ustalona ani za pomocą rentgenografii strukturalnej ani spektroskopii NMR. Zależność promienia bezwładności od masy oraz czynnik kształtu otrzymywane z badań niskokątowego rozpraszania neutronów i promieniowania rentgenowskiego dla roztworów tych białek wskazują na strukturę kłębka statystycznego. Nie wyjaśniają jednak w jaki sposób kłębek statystyczny może w specyficzny sposób oddziaływać z innymi białkami, tworząc aktywne biologicznie kompleksy. Nie jest też do końca jasne, w jaki sposób swobodny, losowo ułożony łańcuch przechodzi do formy uporządkowanej. Łańcuchy białkowe są polimerami o dość złożonej budowie. Każdy mer jest jednym z 20 aminokwasów i może mieć inne własności fizyczne – inny ładunek, objętość lub długość łańcucha bocznego – niż jego sąsiad. Kolejność merów decyduje o lokalnych własnościach łańcucha głównego i wyklucza pewne grupy konformacji. Symulacje Monte Carlo swobodnie błądzącego łańcucha białkowego reprezentowanego przez pełno-atomowy model w sieci FCC mają ułatwić odpowiedz na pytania: (1) czy zdenaturowane i wewnętrznie nieuporządkowanie białka rzeczywiście mają strukturę kłębka? (2) jak rozmiar łańcuchów bocznych może wpłynąć na strukturę całej cząsteczki? oraz (3) jakie oddziaływania determinują ewentualną strukturę lokalną?

Abstract: In my lecture I will talk about some hot topics of AMO and QI by presenting examples of several lines of research, concentrating on theoretical and experimental challenges. The particular subjects will include: a) quantum simulators, i.e. systems capable of simulation of non-trivial and hard to treat quantum many body problems; b) novel kind of numerical and theoretical approaches to many body systems (tensor network states), employing the role of entanglement in many body problems; c) hybrid systems, combining nano-physics with quantum optics.

Abstract: Magnetic nanoparticles (NPs) have been intensively studied because of their unusual physical properties as well as promising applications in a wide variety of fields that range from medicine to nanoelectronics. In this study we consider the use of biomimetic NPs of the very numerous magnetoferritin superfamily as the basis for the realization of 3D magnonic crystals in which the interparticle space is filled with a ferromagnetic material. The use of protein cages as reaction chambers for the production of NPs has a number of advantages. One of them is a high level of homogeneity of the NPs in terms of size and shape, determined by the internal surface of the protein cage. Another major advantage of biomimetic NPs from the point of view of this study is the possibility of producing highly ordered 3D structures by self-assembly [1]. We use the plane wave method to demonstrate that the introduction of a ferromagnetic matrix can lead to the opening of a complete band gap, referred to as a magnonic band gap, in the spin-wave spectrum. We use a model based on a homogeneous medium with effective parameters to interpret the characteristics of the obtained spin-wave spectra in the long wave limit. We also study in detail the width of the band gap and its central frequency versus the matrix material and the lattice constant. The occurrence of a maximum width in the lattice-constant dependence is shown to be closely related to the specific behaviour of the dynamic magnetization profiles of the lowest excitations in the spin-wave spectrum. On the basis of our results we determine the conditions conducive to the occurrence of a complete magnonic band gap. We also show that the crystallographic structure and the lattice constant of the crystals produced by the protein crystallization technique are almost optimized for the occurrence of a magnonic band gap [2,3]. [1] O. Kasyutich et al., J. Appl. Phys. 105, 07B528 (2009).
[2] S. Mamica et al., Phys. Rev. B 86, 144402 (2012).
[3] S. Mamica, J. Appl. Phys. 114, 043912 (2013).

Abstract: During the seminar experimental and theoretical study of the phononic band gap in the hypersonic range for thermally activated surface acoustic waves will be presented. Two dimensional phononic crystals have been studied by the Surface Brillouin Light Scattering. The experiment was performed on the (001) surface of the silicon loaded with two-dimensional square and hexagonal lattice of pillars of different height (100 or 150 nm). It will be presented a new type of surface modes which are related to phononic effects and mechanical eigenmodes of pillars. The experimental data will be compared with results of theoretical modeling by the Finite Element Method.

Abstract: In December 2011 was initiated in Kraków the construction of the first Polish synchrotron – The National Synchrotron Radiation Centre SOLARIS. The energy parameters of SOLARIS (1.5 GeV) allow planning of beam lines utilising the synchrotron radiation from infrared to hard X-rays range. Two beamlines – UARPES (Ultra Angle Resolved Photoemission Spectroscopy) and PEEM/XAS (Photoemission Electron Microscopy/X-ray Absorption Spectroscopy) are currently under construction. Four other new beamlines (IR spectroscopy, XAS/EXAFS spectroscopy, Soft X-ray spectroscopies and multipurpose station – macromolecular crystallography/small angle X-ray scattering/powder diffractometry) are now at different stages of conception and design. First research using synchrotron radiation in SOLARIS can start at the beginning of 2015. The lecture summarized the progress of the construction of the first Polish synchrotron and research opportunities offered.

Abstract: The ground-state properties of bosons loaded into the p-band of a one dimensional optical lattice is studied. It is shown that the phase diagram of the system is substantially affected by the anharmonicity of the lattice potential. In particular, for a certain range of tunneling strength, the full many-body ground state of the system becomes degenerate. In this region, an additional symmetry of the system, namely the parity of the occupation number of the chosen orbital, is spontaneously broken. The state with nonvanishing staggered angular momentum, which breaks the time-reversal symmetry, becomes the true ground state of the system.

Abstract: This work demonstrates that outside of thermodynamic equilibrium, the rate at which energy is dissipated to maintain an ordered state is related to the likelihood of this state being observed. This result is based on a study of a model system in which different (“polymorphic”) non-equilibrium structures are realized for the same values of system’s parameters [1]. Because the polymorphs differ only in the rates of energy dissipation, ϵ – and not in their kinetic or potential energies – it is possible to directly relate probabilities of polymorphs’ occurrence to ϵ. Combination of experiments and simulations indicates that the probability of polymorph/”state” occurrence decreases exponentially with its increasing dissipation rate [2]. In other words, far from thermodynamic equilibrium, nature favors less dissipative states, although the more thermodynamically wasteful structures are also permitted with small probabilities. [1] B. A. Grzybowski, H. A. Stone, and G. M. Whitesides, Dynamic self-assembly of magnetized, millimetre-sized objects rotating at a liquid-air interface. Nature 405, 1033-1036 (2000). [2] K. V. Tretiakov, I. Szleifer, and B. A. Grzybowski, The rate of energy dissipation determines probabilities of non-equilibrium assemblies, Angew. Chem. Int. Ed. 52, 10304-10308 (2013).

Abstract: After the second World War the British sold Enigma to the governments of some of their former colonies claiming that it was unbreakable. To counter untrusted vendors of the devices used in communication tasks quantum information theory offers Device Independent protocols, which can guarantee the security even if the devices are rigged. However, these protocols require parameters which are extremely difficult to obtain in real experiments (so far no group has been able to demonstrate Device Independent QKD). Semi-Device Independent protocols offer good compromise between the level of trust in the vendor of the device and the hardness of physical implementation. In this talk I will introduce the Semi-Device Independent scenario, give the examples of QKD and randomness expansion protocols and report on experimental realizations.

Abstract: Due to decoherence and other well-known issues, physical realization of a scalable quantum computer is not expected to happen in near future. However, it may be possible to design a reversible classical computer that would be free from energy loss due to logical operations. Due to other kind of existing losses it may not be very attractive as a commercial product, but it is interesting to investigate whether we are ready to build a reversible classical computer. We show that we can really build smart reversible circuits for almost all the essential component of a computer. Thus in principle we can build a reversible classical computer. To elaborate on the above claim we first provide a short introduction to the various quantitative measures of the quality of reversible and quantum circuits. To provide a clear distinction between classical reversible circuits and quantum circuits, some foundational aspects of quantum mechanics (specially related to measurement postulate, duality and monogamy) are discussed. The physics behind the strategies adopted for the optimization of various costs of quantum and reversible circuits are explained. Subsequently, two algorithms for optimization of quantum cost are described and optimized quantum costs of different reversible and quantum circuits are shown. As examples, some useful optimized quantum and reversible circuits designed by our group in recent past are shown. Specifically, reversible designs of Montgomery multiplier, sequential elements and ALU of a crypto-processor with minimal gate count, garbage bits, optimal quantum cost and delay are shown. Further to show that optimization strategies discussed in context of classical reversible circuits are also applicable to quantum circuits, we provide a set of optimized quantum circuits useful for construction of entanglement concentration protocols (ECPs) for cat state, GHZ-like state and all families of 4-qubit entangled states.

Abstract: Materials with anomalous (negative) Poisson’s ratio are called auxetics. In contrast to common materials, auxetics shrink when stretched and expand transversally when axially compressed. (Perfect auxetics preserve their shape when changing dimensions. So, in some sense, they show a behaviour opposite to incompressible liquids.) In spite that auxetic systems in the form of man-made structures [1] or self-organising (thermodynamically stable) phases [2] are known for more than 25 years, they are still intensively studied for many potential applications [3,4]. In this lecture the research in the field of auxetics will be briefly reviewed with emphasis on some recent results obtained for auxetic foams [5]. [1] R. S.Lakes, “Negative Poisson’s ratio materials”, Science 235, 1038-1040 (1987).
[2] K. W. Wojciechowski, “Constant thermodynamic tension Monte Carlo studies of elastic properties of a two-dimensional systems of hard cyclic hexamers”, Molecular Physics 61, 1247-125 (1987).
[3] Y. Prawoto, “Seeing auxetic materials from the mechanics point of view: A structural review on the negative Poisson’s ratio”, Computational Materials Science 58, 140-153 (2012).
[4] K. W. Wojciechowski, J. N. Grima, K. L. Alderson, J. Rybicki, “Preface – Auxetic Materials and Related Systems”, Physica Status Solidi B 250, 1959-1962 (2013); see also the references therein.
[5] A. A. Pozniak, J. Smardzewski, and K. W. Wojciechowski, “Computer simulations of auxetic foams in two dimensions”, Smart Materials and Structures 22, article 084009 (2013)

Abstract: This talk summarizes our recent results in the field of quantum routing. First, we define a fully functional quantum router with emphasis on the features such router has to provide. Then we review some of the previously published schemes showing the lack for genuine linear-optical quantum router for individual photons. Subsequently we present our two proposals for linear-optical quantum routers [1,2] and discuss their advantages and disadvantages. Finally we address the experimental implementation that is currently under construction in our laboratory. [1] K. Lemr, A. Černoch, Linear-optical programmable quantum router, Opt. Comm. 300, 282-285 (2013).
[2] K. Lemr, K. Bartkiewicz, A. Černoch, and J. Soubusta, Resource-efficient linear-optical quantum router, Phys. Rev. A 87, 062333 (2013).

Abstract: We propose a linear-optical scheme for heralded qubit amplification. The device is able to change the ratio between probabilities of detecting vacuum or a photonic qubit in the signal transmitted via some lossy channel by using a pair of entangled ancillae. The probability of successful amplification does not asymptotically drop to zero for infinite gain and it can be optimized if (i) some a priory knowledge of input state is known or (ii) some noise in the output signal is tolerated.

Abstract: We summarize ten years of experiments dealing with quantum cloning and implementations of linear-optical quantum devices. We tried several concepts and several platforms for optimal cloning of photon qubits. We developed several linear-optical quantum information processing devices and we used them for cloning.

Abstract: States with sub-Poissonian photon-number statistics obtained by post-selection from twin beams are characterized. States with Fano factors around 0.7 and mean photon numbers around 12 are experimentally reached. Their quasi-distributions of integrated intensity attaining negative values are determined. An intensified CCD camera with quantum detection efficiency exceeding 20 % is utilized both for post-selection and characterization. Experimental results are compared with theory that provides optimum conditions for the experiment.

Abstract: As is widely known, the standard “one oscillator per one mode” quantization of free fields leads to the correct physical prediction <AB>=cos(a-b) for entanglement of linear polarizations, and violates the Bell inequality. This seems to suggest that the tensor product structure associated with the “oscillator per mode” quantization is indeed THE tensor structure associated with quantum fields. However, I will show that <AB>=cos(a-b) is typical also of fields quantized in a different way, where there is no relation at all between the number of modes and the number of oscillators.

Abstract: We present an inequality relating visibility and which-way information for a particle equipped with an internal degree of freedom travelling through a Mach-Zehnder interferometer. The inequality paints an unexpectedly intricate picture of wave-particle duality in the general case. Strikingly, in some instances which-way information becomes erased by introducing classical uncertainty in the internal degree of freedom. Furthermore, even imperfect interference visibility measured for a suitable set of inputs can be sufficient to infer absence of which-way information.

Abstract: We describe how to generate an Einstein-Podolsky-Rosen (EPR) paradox between a mesoscopic mechanical oscillator and an optical pulse. We find two types of paradox, defined by whether it is the oscillator or the pulse that shows the effect Schrodinger called “steering”. Only the oscillator paradox addresses the question of mesoscopic local reality for a massive system. In that case, EPR’s “elements of reality” are defined for the oscillator, and it is these elements of reality that are falsified (if quantum mechanics is complete). For this sort of paradox, we show that a thermal barrier exists, meaning that a threshold level of pulse-oscillator interaction is required for a given thermal occupation n₀ of the oscillator. We find there is no equivalent thermal barrier for the entanglement of the pulse with the oscillator, nor for the EPR paradox that addresses the local reality of the optical system. Our work highlights the asymmetrical effect of thermal noise on quantum nonlocality.

Abstract: The coherence and entangled properties of coupled Gaussian modes of optical systems are discussed. The systems considered are (1) an atomic ensemble located inside a ring cavity, and (2) an optical lattice trapped inside a cavity with a movable mirror. We examine separately the cases of two-mode and three-mode interactions, which are distinguished by a suitable tuning of the mode frequencies. We find that the occurrence of entanglement in the system is highly sensitive to the presence of the first-order coherence between the modes. In particular, the creation of the first-order coherence between modes is achieved at the expense of entanglement between them.

Abstract: Magnonic crystals are the magnetic equivalent of photonic crystals, with spin waves as the counterpart of electromagnetic waves, playing the role of information carriers. We will present short overview of research performed on magnonic crystals offering tailored band structures for spin waves. The promising directions of magnonic crystals research and its applications will be briefly discussed.

Abstract: The contribution is focused on spectroscopic investigations of electronic levels, in particular metastable ones, in free atoms and ions.
A system consisting of a metastable atomic state and the ground state is very favorable for optical atomic frequency standards, since the levels are connected via a forbidden transition with possible application as a “clock” transition. The same system of levels may serve as a basis for construction of a quantum bit.
Within the work some recent achievements in high precision spectroscopy of metastable levels in chromium atoms, obtained with ABMR-LIRF (laser – microwave double resonance on an atomic beam) method [1, 2], are presented. A brief review of experimental investigations of thorium ion structure aimed at construction of an extremely precise optical nuclear frequency standard [3], performed in cooperation in PTB, is also given.
[1] A. Jarosz, D. Stefańska, M. Elantkowska, J. Ruczkowski, A. Buczek, B. Furmann, P. Głowacki, A. Krzykowski, Ł. Piątkowski, E. Stachowska, J. Dembczyński, High precision investigations of the hyperfine structure of metastable levels in chromium atom, J. Phys. B: At. Mol. Opt. Phys. 40: 2785-2797 (2007).
[2] A. Krzykowski, P. Głowacki, A. Jarosz Precise measurements of the hyperfine structure of the levels belonging to the terms 3d⁵4s ⁵G and ⁵P in Cr(I), Acta Phys. Pol. A, 122, 78-81 (2012).
[3] O. A. Herrera-Sancho, M. V. Okhapkin, K. Zimmermann, Chr. Tamm, E. Peik, A. V. Taichenachev, V. I. Yudin, P. Głowacki, Two-photon laser excitation of trapped ²³²Th⁺ ions via the 402-nm resonance line Phys. Rev. A 85, 033402 (2012).

Abstract: Quantum dots are promising candidates for future quantum computing devices. They are also considered as ideal model systems to study fundamental correlations and interactions between single charges and spins. We will here present the basic transport properties of quantum dots coupled to external leads, with a special focus on the strong coupling regime where the electronic correlations can give rise to the Kondo effect. The case of the spin S=1/2 Kondo effect will be analyzed for quantum dots with both nonmagnetic and ferromagnetic leads. Moreover, we will also discuss the SU(4) Kondo effect, which can occur in double quantum dots when the system possesses both spin and orbital degeneracy.

Abstract: Quantum metamaterials are optical media comprised of artificial quantum scatterers (e.g., qubits), in such a way that (1) these unit blocks maintain quantum coherence for times exceeding the characteristic travel time of an electromagnetic wave through the system, and (2) their quantum state can be directly controlled. For example, a periodic arrangement of qubits in a register of an adiabatic quantum computer can be considered as a quantum metamaterial. The simplest case of a quantum metamaterial is a one-dimensional set of superconducting qubits in a transmission line. It was shown in experiment that a single qubit in such a line demonstrates all the expected of a pointlike quantum scatterer, with a much stronger coupling to the field than can be achieved with natural atoms in 3D space. Other implementations of quantum metamaterials (like quantum dots placed inside photonic crystals, which would operate in the optical range) are also being considered. In my talk I will discuss some of the unusual properties of a quantum metamaterial, which stem from its being an extended quantum object, and their possible applications.

Abstract: We study an entangled state of spatially separated electrons, in particular its spins, in a solid state electronic system. The ground state of conventional superconductors is a singlet state of electron Cooper pairs that can provide a natural source of entangled electrons. One of the proposals to obtain the nonlocal entanglement of electrons is to use the Cooper pairs split in the Double Quantum Dot (DQD) system using the Coulomb interaction between electrons [1]. We have analyzed an efficiency of the separation of Cooper pairs in systems, where the DQD is connected to the two superconducting leads, or to the superconducting and normal leads [2,3]. Addressing the idea of quantum communication with entangled electrons in a solid state, where ferromagnetic detectors allow for spin correlation detection, we provide, using quantum information theory, a lower bond on the spin polarization of detectors [4]. In ferromagnetic detectors the spin information is transformed into charge information, however, any real magnetic materials feature imperfect spin polarization due to presence of both spin component in density of states at the Fermi surface. We find that lower bond for the spin polarization is p > 58% for detection of entanglement using an optimal entanglement witness [4]. It provides the minimal spin polarization of ferromagnetic materials that can be useful in quantum communication. [1] L. Hofstetter, S. Csonka, J. Nygard, and C. Schönenberger, Nature 461, 960 (2009).
[2] J. Eldridge, M. G. Pala, M. Governale, and J. König, Phys. Rev. B 82, 184507 (2010).
[3] R. Zitko, J. Lim, R. Lopez, J. Martinek, P. Simon, Phys. Rev. Lett. 108, 166605 (2012).
[4] W. Kłobus, A. Grudka, A. Baumgartner, D. Tomaszewski, C. Schönenberger, and J. Martinek, (in preparation).

Abstract: I will show how to calculate the time-of-flight patterns of strongly interacting bosons confined in two-dimensional square lattice in the presence of an artificial magnetic field. I will discuss the cases with the artificial magnetic field being uniform, staggered or forming a checkerboard configuration. Effects of additional temporal modulation of the optical potential that results from application of Raman lasers driving particle transitions between lattice sites are also included. The presented time-of-flight patterns may serve as a verification of chosen gauge in experiments, but also provide important hints on unconventional, non-zero momentum condensates, or possibility of observing graphene-like physics resulting from occurrence of Dirac cones in artificial magnetic fields in systems of ultra-cold bosons in optical lattices. Also, I elucidate on differences between effects of magnetic field in solids and the artificial magnetic field in optical lattices, which can be controlled on much higher level leading to effects not possible in condensed matter physics.

Abstract: Experimental progress on trapping and manipulating ultra-cold atoms confined in optical lattices has opened new perspectives for controlling many-body states of different quantum systems. In the simplest case such systems are described in the context of the Bose-Hubbard (BH) model. In my talk I will consider the class of extended BH models with additional three-body on-site interactions. After short introduction I will divide the talk into two parts: (i) Standard BH with additional three-body term: I will show that the shape of insulating lobes may crucially depend on the three-body interactions and in the case of attractive three-body term may lead to vanishing of the second insulating lobe [1,2]. (ii) Attractive BH model with soft-core three-body repulsion: I will show that the critical behavior of the system undergoing a phase transition from pair-superfluid to superfluid at integer filling depends on the value of the three-body repulsion. In particular, a critical exponent and the central charge governing the quantum phase transitions are shown to have repulsion dependent features. In consequence, the model extends the list of known systems violating the universality hypothesis [3]. [1] T. Sowinski, Phys. Rev. A 85, 065601 (2012).
[2] T. Sowinski, ArXiv:1307.6852 (2013).
[3] T. Sowinski, R. W. Chhajlany, O. Dutta, L. Tagliacozzo, M. Lewenstein, ArXiv:1304.4835 (2013).

Abstract: A system of two charged particles in a harmonic trap with additional magnetic field is considered. The problem is reduced to a single-particle one in relative coordinates. The ground- and lowest excited-state energies and wave functions are found. The ground state exhibits non-zero expectation value of the velocity (kinetic momentum) and the probability current density does not vanish as well. When the ground state becomes degenerate the expectation value of velocity becomes discontinuous. The effects associated with turning on of the magnetic field are studied by solving the appropriate time-dependent Schroedinger equation. No substantial differences between abrupt (discontinuous in time) and continuous switching on have been observed. Evolution of a wave packet which is initially Gaussian is also investigated. The wave packet loses its Gaussian nature and, after sufficiently large time, a system of diffractive maxima and minima is built.

Abstract: Measures of quantum entanglement are reviewed and compared. We focus quantities characterizing entanglement which could be experimentally accessible. A quantity called ‘collectibility’ is proposed which can be determined in a coincidence experiment involving two copies of the state analyzed. Our approach, initially designed for the case of pure states, works also in the general case of mixed quantum states of a multi-partite system.

Abstract: Recently the protocols of randomness amplification have been introduced secure against quantum and no-signaling adversaries. Here we present the first fully constructive proof of existence of the protocol that is secure against general no-signaling adversary and amplifies arbitrary small randomness (in standard terms of Santha-Vazirani source) in a fully device independent way. The protocol tolerates some amount of noise depending among others on the initial randomness that is to be amplified.

Abstract: One of the current trends in quantum physics is the quest for controllable quantum many-body systems which can be used as quantum simulators. In particular, there is a growing interest in simulating spin and quantum magnetism. In recent years, the focus is moving from SU(2) spins towards SU(N)-symmetric models. The SU(3) systems, having their origin in nuclear physics, were a fruitful playground for quantum chaos investigations, in particular due to they reach possible behavior in the classical limit. Now it seems to be possible to realize such models experimentally with trapped ions providing a large degree of control from the experimental point of view.

Abstract: In Quantum Optics the widely used definition of nonclassicality is based on the Glauber-Sudarshan P function [1]. If the P function has the properties of a classical probability density, the state is a classical mixture of coherent states. In any other case, the quantum state clearly shows quantum interference effects. In general, the P function is strongly singular and, hence, not applicable in experiments. A universal regularization resolves this problem [2], as it was demonstrated in experiments. In view of its structure [3], entanglement can also be visualized by quasiprobabilities. This requires an optimization based on the solution of the separability eigenvalue problem [4]. Its extension to the multipartite case yields multipartite entanglement witness for complex quantum states [5]. To characterize general quantum correlations, the concept of the P function was extended to a functional [6]. Its regularized version visualizes quantum correlations, even when the state is not entangled and has zero quantum discord [7]. [1] E. C. G. Sudarshan, Phys. Rev. Lett. 10, 277 (1963); R. J. Glauber, Phys. Rev. 131, 2766 (1963).
[2] T. Kiesel and W. Vogel, Phys. Rev A 82, 032107 (2010).
[3] R. F. Werner, Phys. Rev. A 40, 4277 (1989).
[4] J. Sperling and W. Vogel, Phys. Rev. A 79, 042337 (2009).
[5] J. Sperling and W. Vogel, Phys. Rev. Lett. 111, 110503 (2013).
[6] W. Vogel, Phys. Rev. Lett. 100, 013605 (2008).
[7] E. Agudelo, J. Sperling, and W. Vogel, Phys. Rev. A 87, 033811 (2013).

Abstract: We consider relations between communication complexity problems and detecting correlations (violating local realism) with no local hidden variable model. We show first universal equivalence between characteristics of protocols used in that type of problems and non-signaling correlations. We construct non linear bipartite Bell type inequalities and strong nonlocality test with binary observables by providing general method of Bell inequalities construction and showing that existence of gap between quantum and classical complexity leads to violation of these inequalities. We obtain, first to our knowledge, explicit Bell inequality with binary observables and exponential violation.

Abstract: We discuss recent concepts of non-Markovianity of quantum evolution. The discussion is illustrated by simple examples (pure decoherence, amplitude damping and random unitary dynamics).

Abstract: We present multi-partite Hardy-type test against local realism. For n qubit systems, we prove the uniqueness and purity of the Hardy state (that is the one that satisfies Hardy conditions), and its genuine n-partite entanglement. We show an that Hardy correlations allow one to find solutions to some quantum communication problems. As an example we present a secure quantum scheme for the original Byzantine Generals problem. Our protocol is based on Hardy’s paradox, which uses a set of conditions impossible for classical systems, but satisfied by a unique quantum two-particle state, and on entanglement swapping methods.

Abstract: Incessant run of successes of quantum mechanics suggests that quantum formalism plays decisive role in the description of physical phenomena. It leads inevitably to the problem: How does Nature create a “foot-bridge” from fragile quanta to the objective world of everyday experience? The subject of the talk will provide an answer to this fundamental issue. We will show how a crucial for quantum mechanics notion of non-disturbance due to Bohr and a natural definition of objectivity lead to a canonical spectrum broadcasting structure of a quantum system-environment state, reflecting objective information records about the system stored in the environment.

Abstract: This commemoration intertwines between various physical ideas (as presented in the title), shared within the scientific works of Professors: Stanisław Kielich, Louis Michel, Jan Mozrzymas, Joshua Zak, Marian Surma, and others. It goes from experimental studies on Cotton-Mouton effect (heavy electromagnesses in the basements of Collegium Chemicum), through symmetry considerations in phase transitions (nematics, smectics, etc., mainly breaking of symmetry, but, somehow exceptionally, also ascent), to the magnetic translation group as a mathematical tool for the Bohm-Aharonov effect (everybody knows Landau levels of a free two-dim electron gas, and the magnetic translation group serves as an equivalent for the case of itinerant electrons, with its irreducible representations labeling the levels, and the basis functions describing degenerate cyclotronic orbits). Nowadays, these ideas can be converted to “reality” within nanotechnology, e. g. magnetic quantum dots.

Abstract: This work contains investigation results of the structural and nonlinear optical properties of organometallic thin films and nanostructures. The films and nanostructures were successfully grown by Physical Vapor Deposition technique in high vacuum on transparent (quartz, glass) and semiconductor (n-type silica) substrates kept at room temperature during the deposition process. Selected films were annealed after fabrication in ambient atmosphere for 24 hours at the temperature in the range from 50^oC to 250^oC. Spectral properties were examined using transmission, photoluminescence, Second and Third Harmonic Generation’s techniques. The experimental spectra were allowed to determine optical constant of the films. Structural properties were investigated by AFM measurements. The organometallic films and nanostructures exhibit high structural quality regardless of the annealing process, but the stability of the film can be improved by using an appropriate temperature during the annealing process. We find that the optical properties were strictly connected with the morphology and the annealing process can significantly change the structural properties of the films and lead to the formation of various nanostructures.

Abstract: One of the possibilities to obtain efficient and stable nonlinear optical (NLO) material is to dope an amorphous polymer with organic donor-acceptor molecules forming a composite. The appropriate material for the first NLO effect as persistent second harmonic generation (SHG) requires large number of polarizable molecules embedded in polymeric matrix preventing polar orientation. The polar orientation may be induced by external electric field at the temperatures where the matrix is sufficiently mobile to allow fast alignment of the dopants. The experimental explanation of the origin of their NLO response is very difficult because optical susceptibilities are measured in condensed matter where the molecular properties are affected by the host matrix. Molecular simulations can help to explain the nature of the guest-host interaction and separate the different contribution of the material to the optical output signal. A goal of many theoretical works is to find appropriate model describing optical properties of molecules incorporated into polymeric environment. In the presented work linear and nonlinear optical susceptibilities of guest-host polymer systems were calculated applying the hierarchic procedure . The wild variety of chromophores characterized by different size, shape and charge distribution incorporated into different polymer matrix were studied. First of all the structures of the investigated systems have been modeled by molecular dynamic simulations applying molecular mechanics CVFF force field method. The obtained structures are amorphous. Investigations of radial distribution function prove that location of chromophores in polymeric matrix is an intrinsic property of polymer. The motion of polymer chain allows a rotation of dopants under influence of an external electric field. The electronic properties of the NLO chromophores were computed at the HF and DFT level using different exchange – correlation potentials. These properties were investigated for the isolated NLO molecules as well as for the ones in polymer environment. In the second case the first-order susceptibilities corresponding to SHG were calculated using discrete local field approach. The implemented method is very efficient to the molecules with high charge transfer effect and give the data approximately consistent with the experimental results. It was also proved that the optical response, especially NLO output signal of chromophores embedded into polymeric matrix, depends on their local environment.

Abstract: The research of a refraction law played a major role in the development of the optics since the first attempts of Ptolemy until the more accomplished results of Ibn Sahl, Snel or Descartes. However, it is necessary to wait for the beginning of the XIXth century, much later than the theory of colours of Newton and thanks to the researches on the achromatic glasses, so that emerges the concept of refractive index and so that it begins to be understood well. We propose a historical reminder and an outline of the obstacles and epistemological advances which allowed to establish it.

Abstract: The fibre bundle approach [1] has been applied to the unified description of all the eight fundamental magnetic structures and their symmetry groups [2]. On this basis the explicit formulas describing both the variety of magnetic structures and their symmetry groups have been derived. In the particular case of the spin glass state (SGS) the global magnetic coupling constant has been interpreted as a section of the corresponding fibre bundle. The fibre of this bundle makes the space of the Gaussian distributions. Thus one can say that the randomness of the distribution of both the magnetization and the individual magnetic moments in the SGS is of the Gaussian-like character. An observation was made that another kind of the fibre bundle sections make the magnetization vectors M multiplied by a certain Gaussian factor defined in R³, the last factor making the problem continuous and more physical [3, 4]. In one of the previous papers the authors have proved that an internal spontaneous magnetic field H_int is necessary for the SGS to be stable and just to exist [5]. For the angle between M and H_int equal to ϕ one can say that at ϕ=const any rotation (precession) of M around the direction of H_int makes the operation of symmetry of the SGS. Thus the magnetic symmetry group of SGS turns out to be SO(2). The role of both the H_int and the external magnetic field H_ext as well as of the average kinetic energy E_kin of the separate magnetic atoms in the explanation of the experimental temperature dependencies of susceptibility is shown. Thus the fibre bundle approach equates the method of the symmetry analysis of magnetic structures with the method of the higher dimensional embeddings of the modulated structures. The symmetry groups appearing in the method of the symmetry analysis become the structural groups of the bundles. From the other side a higher dimensional space needed to the description of a modulated structure makes here the total space of the bundle. Thus these three methods, namely the symmetry analysis, the higher dimensional embeddings and the fibre bundles are equivalent. The analogous situation is with the description of the magnetic structures with the use of the spin groups, where an additional type of symmetry is introduced. Note that the Gaussian factor introduced above plays a double role: it makes the vector M to be a field and simultaneously makes the description of the magnetic structures more physical [6, 7]. It seems that the fibre bundle approach could serve also for the description of the symmetry groups of all the other aperiodic structures, like e.g. the modulated nonmagnetic structures, quasicrystals (nonmagnetic and magnetic) etc. It is worthwhile to mention here that these different magnetic structures under consideration have been found by the authors to be related with the values of the certain topological invariants [8].
 
[1] Sulanke, R. Wintgen, P., Differentialgeometrie und Faserbundel, Berlin (1972)
[2] J. Warczewski, P. Gusin, D. Wojcieszyk, Mol. Cryst. Liq. Cryst. 554 (2012), 209-220
[3] J. Warczewski, P. Gusin et al. Central European Journal of Physics 5(3) 2007 377-384
[4] P. Gusin and J. Warczewski, Mol. Cryst. Liq. Cryst. Vol. 521: pp. 288-292, 2010
[5] J. Warczewski, P. Gusin et al., J. Phys.: Condens. Matter, 21 (2009) pp. 035402- 035407
[6] J. Warczewski, J. Krok-Kowalski, P. Gusin et al., J. of Non-Linear Optics, Quantum Optics, Vol. 30, (2003) pp. 301-320
[7] J. Warczewski, J. Krok-Kowalski, P. Gusin et al., Journal of Physics and Chemistry of Solids 66 (2005) 2044-2048
[8] P. Gusin and J. Warczewski, J. of Magn. and Magn. Mat., 2004, 28(1/2-3), 178-187

Abstract: The ellipsometric parameters for light reflection from a dielectric film with Kerr optical nonlinearity on a bigyrotropic magneto-electric film are theoretically investigated. The combined contributions of the cubic optical nonlinearity and the magneto-electric coupling allows to control the ellipsometric parameters and thus for example the Kerr rotation with the incoming light intensity, in particular at incidence angles close to the pseudo-Brewster angle.

Abstract: We show that the direct measurement of the beam radius in Z-scan experiments using a CCD camera at the output of a 4f-imaging system allows a higher sensitivity and a better accuracy than other methods. One of the advantages is to be insensitive to pointing instability of the pulsed laser because no hard aperture is employed as in the usual Z-scan. In addition, the numerical calculations involved here and the measurement of the beam radius are simplified since we do not measure the transmittance through an aperture and it is not subject to mathematical artefacts related to a normalization process, especially when the diffracted light is very low. Keywords: Nonlinear optics, Z-scan, diffraction, image processing, Fourier optics

Abstract: Bi₂ZnOB₂O₆ nonlinear optical single crystals were grown by means of the Kyropoulos method from stoichiometric melt. The SHG and THG response of the Bi₂ZnOB₂O₆ crystal was studied by the Maker fringes techniques. Moreover SHG microscopy studies were carried out providing two-dimensional SHG images as a function of the incident laser polarization. The crystals have been shown to have high SHG and THG efficiency, comparable with those of well-known crystals such as BBO, KDP, KTP, which makes them very attractive materials for NLO applications. The high nonlinear optical efficiency combined with the possibility to grow high quality crystals make Bi₂ZnOB₂O₆ an excellent candidate for photonic applications.

Abstract: We present a general method for the quantification of the performance of quantum chemical methods over an arbitrary collection of atomic/molecular properties. Our approach relies on the Minkowski metric, graph theoretic concepts and pattern recognition techniques. The method should be of interest as a rigorous approach to the introduction of order and classification in spaces of theoretical descriptions. We show how it can be used to quantify the relative merit of ab initio and DFT methods.

Abstract: The primary goal of a theory of liquid mixtures is to determine, using statistical mechanics, how the structure and free energy varies with the composition, and with the chemical composition of its components. Such a theory provides the key to the determination of dielectric and spectral properties, phase transitions, critical points, solubilities, immiscible regions, metastable and unstable regions, etc. Theories proposed in the first half of the 20th century were, for the most part, lattice theories, and many of these are described in the books by Guggenheim [1] and Prigogine [2]. These early theories pre-dated molecular simulations and the availability of electronic computers, so that they were “tested” by direct comparison with experimental data. Since such comparisons, in the case of the lattice theories, involved adjustment of various parameters to experimental data, these tests were of dubious value. Once molecular simulation data became available in the early 1960’s these theories were shown to be in serious error, and can now be considered to be extinct. Modern theory of polar liquids (the last 60 years) has followed a dual path. The first has been perturbation theory, in which the free energy and other properties of the solution of interest are related to those of a simpler solution having simple intermolecular forces, for example hard spheres or Lennard-Jones mixtures. Perturbation theory has been particularly successful for thermodynamic properties. The theory of Wertheim [3], relates the free energy of a polar or associating fluid to that of a hard body (non-associating) fluid through a clever resummation of a cluster series for the free energy. It and its later extensions are finding widespread practical application [4]. The second route to a theory of polar liquids has been integral equation theory, which yields the structure in the form of distribution functions [5]. Although less successful than the perturbation theories for thermodynamic properties, integral equation theories have been successful for other properties, in particular dielectric and spectral properties. References
[1] E.A. Guggenheim, “Mixtures”, Clarendon Press, Oxford, 1952.
[2] I. Prigogine, “The Molecular Theory of Solutions”, North-Holland Pub. Co., Amsterdam, 1957.
[3] Wertheim, M.S. J. stat. Phys. 35, 19 (1984); ibid. 35, 35 (1984); ibid. 42, 459 (1986); ibid. 42, 477 (1986).
[4] For reviews of the theory and its extensions, and practical applications, see: Müller, E.A. and Gubbins, K.E. Ind. Engng. Chem. Research, 40, 2193 (2001); Tan, S.P., Adidharma, H. and Radosz, M., Ind. Eng. Chem. Research, 47, 8063 (2008).
[5] C.G. Gray and K.E. Gubbins, Theory of Molecular Fluids. I. Fundamentals, Chap. 5, Oxford University Press (1984); C.G. Gray, K.E. Gubbins and C.G. Joslin, Theory of Molecular Fluids. II. Applications, Chap. 9-11, Oxford University Press (2011).

Abstract: Physics of dielectrics started in Poznań when professor Arkadiusz Piekara took chair in Experimental Physics at the Poznań University in 1952. At the beginning a lot of effort was taken to prepare the measuring basis, that is to construct the measuring condensers, Schering bridges, resonance circuits, heterodyne beat apparatus (∆C/C ≈ 10⁻⁶), to purifying liquid dielectrics and to synthesize ferroelectrics. Later, professor Piekara got Stanisław Kielich interested in theoretical approach to the physics of dielectrics and his Master of Science dissertation in 1955 can be considered as the beginning of the work of young Poznań staff in theory of dielectrics.

Abstract: We have investigated optically induced ultrafast magnetization dynamics of a series of Fe55Pt45/Ni80Fe20 exchange spring bi-layers with varying Ni80Fe20 thickness by time-resolved magneto-optical Kerr effect measurements. Rich spin wave spectra are observed and the spin-wave frequency shows a strong dependence on the Ni80Fe20 layer thickness. Micromagnetic simulations reproduced the experimental data qualitatively after considering pinning of spins at the Fe55Pt45/ Ni80Fe20 interface and an effective magnetic field gradient across the thickness of the Ni80Fe20 layer. The spin twist structure introduced in the Ni80Fe20 layer gives rise to new modes in the composite system as opposed to the bare Ni80Fe20 films.

Abstract: We analyze the protocol of randomness amplification using Bell inequality violation in terms of the convex combination of no-signaling boxes required to simulate quantum violation of the inequality. We present intuitive proof for the range of partial randomness from which perfect randomness can be extracted using quantum correlations violating the chain inequalities. We derive exact values in the asymptotic limit of a large number of measurement settings.

Abstract: We analyze the eigenstate thermalization hypothesis (ETH) for the single impurity Anderson model, focusing on the Kondo regime. For this we construct the complete eigenbasis of the Hamiltonian using the numerical renormalization group method in the language of the matrix product states. We calculate the spectral function of the quantum impurity (a quantum dot) for the ground state and several excited states of the system using the microcanonical and diagonal ensembles. These spectral functions are compared to the time-averaged spectral function obtained by time-evolving the initial state according to the full Hamiltonian and to the spectral function calculated using the thermal density matrix. We find good agreement between the spectral functions calculated this way, which indicates that the process of thermalization happens at the level of individual eigenstates, indeed. We also discuss the behavior of the spectral functions calculated for states with the bath initially in its ground state. In certain cases then, this mandates the alternative interpretation in terms of a quantum quench. The distinctive features as compared to ETH are highlighted.

Abstract: Physical-chemical reasoning is used to demonstrate that the sizes of both prokaryotic and eukaryotic cells are such that they minimize the times needed for the macromolecules to migrate throughout the cells and interact/react with one another. This conclusion does not depend on a particular form of the crowded-medium diffusion model, as thus points toward a potential optimization principle of cellular organisms. In eukaryotes, size optimality renders the diffusive transport as efficient as active transport – in this way, the cells can conserve energetic resources that would otherwise be expended in active transport.

Abstract: Biomedreg is a collaboration project to join several bio-sciences groups. This centre provides research activities ranging from organic synthesis to medicinal research.

Abstract: The talk will provide an overview of the RCPTM – a regional centre of scientific collaboration across various natural sciences (physics, chemistry, nanomaterials). The capabilities in contract and collaboration research will be presented.

Abstract: Artificial ferromagnetic nanostructures with periodic lateral contrasts in magnetization are known as “magnonic crystals” (MCs), conceived as the magnetic analogue of photonic crystals. Recently, there is growing interest in the fundamental understanding of the spin wave propagation in MCs because of their huge potential in a wide range of applications such as microwave resonators, filters and spin wave logic devices. With advances in controlled nanofabrication techniques, it is now possible to synthesize high-quality periodic bi-component magnetic nanostructures with precisely controlled dimensions. The band spectrum of MCs consists of allowed states magnonic bands and forbidden states (magnonic gaps) that can be tuned by magnetic fields or geometrical parameters. We have shown that MCs represent a perfect system for studying excitations on disordered periodical lattices because of the possibility of controlled variation in the degree of disorder by varying the applied magnetic field [1]. We have also demonstrated functionality of magnetic logic based on a reconfigurable MC in the form of a meander-type ferromagnetic nanowire [2]. A ferromagnetic resonance method employing a microscopic coplanar waveguide was used to detect the logic state of the structure coded in its magnetic ground state. This talk will be divided into 3 parts: the first part will focus on strategies we have developed for synthesizing high-quality 1-D and 2-D MCs using deep ultra-violet lithography technique at 248 nm exposure wavelength. Using resolution enhancement techniques, we have fabricated arrays of ferromagnetic nanostructures with lateral dimensions and inter-element spacing below the conventional resolution limit of optical lithography tools. The second part will focus on results of our recent systematic investigation of both the static and dynamic properties of MCs using a combination of magneto-optical Kerr effect measurements, magnetic force microscopy, broadband ferromagnetic resonance spectroscopy, magneto transport measurements and micromagnetic simulations. In the third part, the concept of binary magnetic nanostructures will be introduced and their potential application in magnetic logic devices demonstrated. [1] J. Ding, M. Kostylev, and A. O. Adeyeye, Physical Review Letters 107,047205 (2011).
[2] J. Ding, M. Kostylev, and A. O. Adeyeye, Applied Physics Letters 100, 062401 (2012).

Abstract: The threshold between classical and nonclassical two-qubit states is drawn at the place when these states can no longer be described by classical correlations, i.e., quantum discord or entanglement appear. However, to check if the correlations are classical (in terms of quantum discord and entanglement) it is sufficient to witness the lack of quantum discord because its zero value implies the lack of entanglement. We explain how the indicator of quantum discord introduced by Girolami and Adesso [Phys. Rev. Lett. 108, 150403 (2012)] can be practically measured in linear-optical systems using standard beam splitters and photon detectors. We also show how to the setup can be modified to efficiently investigate the degree of Bell-CHSH inequality violation.

Streszczenie: Periodyczne heterostruktury półprzewodnikowe są układami z podwójną periodycznością. Periodyczność sieci krystalicznej powoduje powstanie przerwy energetycznej (o szerokości od ułamka eV do pojedynczych eV), która w litym materiale wyraźnie rozdziela prawie całkowicie obsadzone pasmo walencyjne do prawie pustego pasma przewodnictwa. Wprowadzenie periodycznej strukturalizacji, np. poprzez wytworzenie heterostruktury półprzewodnikowej, o okresie rzędu kilku lub kilkudziesięciu nm prowadzi do wytworzenia miniprzerw energetycznych w obrębie wierzchołka pasma walencyjnego i dna pasma przewodnictwa o szerokościach istotnie mniejszych od szerokości przerwy energetycznej litego półprzewodnika. Stany elektronowe i dziurowe o energiach bliskich dna pasma przewodnictwa i wierzchołkowi pasma walencyjnego mogą być opisane w przybliżeniu kp za pomocą równania Schrodingera ze zmienną przestrzennie masą efektywną nośnika, odpowiednio, elektronów i dziur.
Rozdzielanie pasma przewodnictwa i pasma walencyjnego na minipasma może zwiększyć efektywność produkcji par elektron-dziura przy absorpcji światła słonecznego. Efekt ten wynika z ograniczenia procesów termalizacji oraz z pojawienia się nowych przejść pomiędzy minipasmami. Zostaną przedstawione wyniki obliczeń teoretycznych efektywności ogniw słonecznych działających w oparciu o dwuwymiarowe periodyczne heterostruktury półprzewodnikowe na bazie AsGa/AlGaAs dla różnych geometrii rozważanych układów.

Streszczenie: Prezentowana jest niezmiennicza procedura kwantyzacji na przestrzeni fazowej oraz jej niezmiennicza reprezentacja operatorowa w przestrzeni Hilberta nad płaską przestrzenią konfiguracyjną. W konsekwencji pokazana jest konstrukcja poprawnych operatorów położenia i pędu dla kanonicznych zmiennych krzywoliniowych oraz ich odpowiedni porządek w hamiltonianie.

Abstract: Determination of photon-number statistics [1,2] of twin beams based on the measurement of photocount statistics by an iCCD camera is discussed. The approach based on the superposition of signal and noise [3] applied to paired fields is analyzed in detail and compared with that based on the method of maximum likelihood. Advantages of the use of an iCCD camera as well as limitations are mentioned [4]. A method for the determination of absolute quantum detection efficiency based on the measurement of photocount statistics of twin beams is suggested [5]. The measured histograms of joint signal-idler photocount statistics allow to eliminate an additional noise superimposed on an ideal calibration field composed of only photon pairs. This makes the method superior above others presently used [6]. Values of the inquired quantum detection efficiencies in the signal- and idler-field paths are derived from the first- and second-order experimental photocount moments combined with the method of least-square declinations from the experimental histogram. Post-selection from twin beams is used to generate conditional sub-Poissonian light with Fano factors up to 0.62 using the iCCD camera. Possibilities as well as limitations of this approach are analyzed. References:
[1] O. Haderka, J. Peřina Jr., M. Hamar, and J. Peřina, Phys. Rev. A 71, 033815 (2005).
[2] J. Peřina Jr., O. Haderka, V. Michalek, and M. Hamar, Phys. Rev. A 87, 022108 (2013).
[3] J. Peřina and J. Křepelka, J. Opt. B: Quant. Semiclass. Opt. 7, 246 (2005).
[4] J. Peřina Jr., O. Haderka, M. Hamar, and V. Michalek, Phys. Rev. A 85, 023816 (2012).
[5] J. Peřina Jr., O. Haderka, M. Hamar, and V. Michalek, Opt. Lett. 37, 2475 (2012).
[6] G. Brida, I. P. Degiovanni, M. Genovese, M. L. Rastello, and I. R. Berchera, Opt. Express 18, 20572 (2010).

Abstract: This talk will feature some classical results in the physical theory of information processing. First we’ll take a look at a model of computation based on irreversible laws of macroscopic physics. We’ll investigate its relationship with entropy and obtain the famous Landauer’s principle. We’ll further see how this principle limits the power of our computers and how it deals with the Maxwell demon. Later we’ll consider why and how to build a model of computation based on reversible laws of microscopic physics.

Abstract: Numerical methods, which analyse the output of micro-magnetic simulations can be employed to extract desirable information. The presentation will discuss what information is usually required from theoretical and experimental aspects and how one can go about obtaining them. Apart from visualizing the evolution of magnetization with time in these mediums, methods to plot spin-wave power in frequency and wavevector domain shall also be discussed.

Abstract: The properties of quantum dimer model are investigated on 42-site Sierpiński lattice. This is a self-similar lattice with, to some extend, the corner-sharing triangles. It is interesting that the entropy of dimer coverings of Sierpiński lattice is the same as that for the kagomé lattice (1/3 ln 2). We demonstrate that the quantum dimer model has short-range dimer-dimer correlations and gapped dimer-liquid phase with topological degeneracy. A full spectrum of a dimer liquid is obtained.

Abstract: Usually, magnetic behavior in the nanoscale is described by the Landau-Schlitz-Gilbert equation. This enables us, for instance, to model and understand time-related issues, like: precession, or magnetization switching. In my talk I will shortly describe this equation and its importance. Then, I will speak about temperature, its influence, and how it can be included into the model. I will describe the problem from two perspectives. There exists namely an atomistic approach, where every single spin is modeled. For larger systems we use continuum theory-micromagnetism. This will lead me to the recently proposed Landau-Schlitz-Bloch equation. The talk will be supported with results of numerical simulations.

Abstract: Quantum entanglement is a fascinating phenomenon, especially if it is observed at the macroscopic scale. Importantly, macroscopic quantum correlations can be revealed only by accurate measurement outcomes and strategies. Here, we formulate feasible entanglement witnesses for bright squeezed vacuum in the form of the macroscopically populated polarization triplet Bell states. Their testing involves efficient photodetection and the measurement of the Stokes operators variances. We also calculate the measures of entanglement for these states such as the Schmidt number and the logarithmic negativity. Our results show that the bright squeezed vacuum degree of polarization entanglement scales as the mean photon number squared. We analyze the applicability of an operational analog of the Schmidt number. Reference: Phys. Rev. A 86, 022323 (2012)

Abstract: It is shown that maximally efficient protocols for secure direct quantum communications can be constructed using any arbitrary orthogonal basis. This establishes that no set of quantum states (e.g. GHZ states, W states, Brown states or Cluster states) has an advantage over the others, barring the relative difficulty in physical implementation. This provides a wide choice of states for experimental realization of direct secure quantum communication protocols. We have also shown that this protocol can be generalized to a completely orthogonal state based protocol of Goldenberg-Vaidman (GV) type. The security of these protocols essentially arises from duality and monogamy of entanglement. This stands in contrast to protocols that employ non-orthogonal states, like Bennett-Brassard 1984 (BB84), where the security essentially comes from non-commutativity in the observable algebra. This observation is exploited to classify the quantum communication protocols into two broad (but not exclusive) classes: A) protocols based on conjugate coding, which require the non-commutative structure of the physical theory; and B) superposition-based protocols, where security arises from non-realism and linearity.

Abstract: The ancient Greeks and Romans used several methods of hiding secret messages written in plaintext, but seldom had recourse to cryptography in the proper sense. Two examples of its application – Caesar’s substitution cipher and a Spartan transposition ciphering device – are discussed based on accounts by Aulus Gellius and other authors.

Streszczenie: Energetyka jądrowa (EJ) budzi wiele kontrowersji, a powszechna wiedza na jej temat zdominowana jest przez mity i nieporozumienia. Seminarium będzie próbą odpowiedzi na pytania: EJ na świecie po Fukushimie: regres czy renesans? Dlaczego Niemcy rezygnują z EJ? Czy EJ jest potrzebna Polsce? Program Polskiej EJ: jakim cudem jest realizowany, skoro nie jest zatwierdzony?

Streszczenie: Hipoteza Riemanna (RH) mówi o położeniu na płaszczyźnie zespolonej nietrywialnych zer funkcji dzeta dzeta(s) Riemanna. Jest ona jednym z najbardziej znanych nierozwiązanych problemów w matematyce. Po sformułowaniu hipotezy Riemanna kilka minut poświęcę anatomii dzety Riemanna. Zasadnicza część wykładu będzie poświęcona omówieniu związków RH z fizyką: Twierdzenie Woronina i fraktalność dzety(s). Elektromechaniczny układ van der Pola. Przypuszczenie Polya’i-Hilberta, korelacje zer dzety: praca Montgomerego, macierze losowe, hamiltonian Okubo, Berry: H=xp. Związki z chaosem kwantowym. Modele Isinga i RH. Bilardy i RH. Ruchy losowe i RH.

Abstract: Fundamental understanding of spin dynamics and reversal in a system with a reduced dimensionality is essential in the future advancements of nanomagnetism and spintronics. Thus, it becomes important to explore the spin excitations in sub-micron magnetic particles such as dots. For mesoscopic and nanoscale sizes of dots, non-uniform magnetization distributions with zero remanence (“vortex” states) are often observed at equilibrium [1]. The magnetic vortex with the in-plane curling magnetization and the out-of-plane magnetization at the core is the simplest topologically non-trivial ground state in ferromagnetic dots. The vortex states are stable within a wide range of dot sizes from a few tens of nm up to a few tens of microns. Vortex related phenomena offer insight into spin dynamics on a fundamental level, and also govern magnetization reversal. In this talk, I will present a review of calculations and measurements of the spin excitations in the vortex ground state of soft magnetic dots. The spectrum of spin excitations consists of a low-frequency gyrotropic (sub-GHz range) mode describing precessional motion of the vortex core and high-frequency modes describing spin excitations of the vortex planar part. Nontrivial spin dynamic properties, such as magnetic vortex core (VC) polarization reversal driven by small-amplitude, oscillating (pulse) magnetic fields or spin polarized currents, were observed [2]. Special interest in the vortex dynamics is inspired by the possibility of easy and controllable dynamical switching of the VC magnetization direction (polarization). The dynamical origin of the VC polarization reversal will be considered. We derived a phase diagram of the VC reversal and its switching time with respect to both the driving field strength and frequency. The interaction of high frequency azimuthal spin waves with the moving VC [3] and their influence on the VC motion will be discussed. There is a giant frequency splitting of the spin waves having non-zero overlapping with the vortex mode as well as a finite vortex mass of dynamical origin. We calculated also the main dynamic parameters of the spin polarized current induced magnetic vortex oscillations in nanopillars, such as the range of current density, where the vortex steady oscillation state exists, the oscillation frequency and VC orbit radius [4]. References:
[1] K.Y. Guslienko, J. Nanosci. Nanotechn. 8, 2745 (2008).
[2] B. Van Waeyenberge et al., Nature 444, 461 (2006); K. Yamada et al., Nature Materials 6, 269 (2007).
[3] K.Y. Guslienko et al., Phys. Rev. Lett. 101, 247203 (2008); Phys. Rev. B 81, 014414 (2010).
[4] K.Y. Guslienko et al., J. Phys.: Conf. Ser. 292, 012006 (2011).

Abstract: It has been predicted theoretically and observed experimentally that a direct current traversing a magnetic multilayer exerts a spin torque on the magnetic system which can compensate the natural damping and lead to self-sustaining magnetic oscillations in the GHz range. Due to the easy frequency tunability of the spin torque nano-oscillators (STNOs) this effect has great potential for the construction of nanosized microwave gen- erators. The main problem which has to be solved for future applications is the low output power of a single STNO. Some experiments have already been performed which show that it is possible to synchronize two STNOs. The output power for N synchronized STNOs could in principle scale with N². However, in order to construct larger arrays of STNOs a good knowledge about the interaction mechanism between them is indispensable, which can be obtained by means of micromagnetic simulations. This talk will give a general overview of the magnetization dynamics of an extended thin magnetic film excited by a direct current through a point contact. The oscillation below the point contact can excite propagating spin waves which provide an important mechanism for the interaction between STNOs. We will present micromagnetic simulation results concerning the synchronization of two STNOs which show that there can exist several different synchronized states, whose dynamics are determined by the characteristics of the involved spin waves.

Abstract: Spin wave dispersion relations in ferromagnetic thin films are often calculated within a continuum model based on the Landau-Lifshitz equation thereby neglecting the underlying lattice structure in real materials. In this talk we present and analyze some differences between the spin wave modes obtained in a lattice model and the well known results of the continuum model. For this purpose we calculate the spin wave dispersion with a discrete model consisting of classical spins which are stacked on a cubic lattice and interact via exchange and dipolar forces. In the case of magnetostatic modes, the discrete model yields new qualitative features in comparison with the results of Damon and Eshbach. We observe several surface modes and the degeneracy of the spin waves which propagate perpendicularly to the applied magnetic field is lifted. We also show that the dipolar-exchange modes are strongly influenced by the boundary conditions in ultra-thin films and undergo a frequency upshift. Finally, we compare the 2d-limit of the continuum model with the case of a single layer in the discrete model.

Abstract: Knowledge of the structure, molecular correlations and mechanisms of structural processes taking place in liquids are of fundamental importance for understanding of their physical and chemical properties. X-Ray diffraction studies of liquids open a possibility of finding relations between their structures and properties. Liquids have been divided into certain classes (homologue series) according to certain properties. The lecture is concerned with presentation of application of X-Ray diffraction method to investigation of intra- and intermolecular interactions and close-range structure in selected complex liquids. X-ray structural study brings information on the types of molecular associations contributing to determination of the liquid nature and mechanisms of processes taking place in it. The close-range ordering is related to the mode of packing of molecules in the liquid. According to molecules in liquid have at their disposal 35% of free space. Structure of liquid can be described by the radial distribution function (RDF). This function permits determination of such parameters as the sphere radii, coordination numbers and degree of ordering. The close-ordering range determined in the liquids studied by the WAXS method is about 2 nm.

Abstract: Koniec XX wieku przyniósł wielkie zmiany w paradygmatach fizyki molekularnej i biologii. Doszło do powstania nowych dziedzin nauki – nanotechnologii i biologii systemowej. Są to zupełnie rozdzielne dziedziny badań. W konsekwencji trudno jest obecnie jednoznacznie określić interdyscyplinarny kierunek badań, jakim była biofizyka.

Abstract: Fotoogniwa barwnikowe (DSSC: Dye-Sensitized Solar Cells), należą do nowej, obiecującej generacji ogniw słonecznych, w których podstawą funkcjonowania jest oddziaływanie barwników organicznych z warstwami nanocząstek tlenków metali (najczęściej tlenku tytanu). Fotogniwa barwnikowe zostały po raz pierwszy zaproponowane stosunkowo niedawno, w pionierskiej pracy w Nature w 1991 r. Ich obecna sprawność może przekraczać 12%, a znacznie mniejsze koszty produkcji oraz lepsza wydajność w warunkach umiarkowanego i słabego oświetlenia (wewnątrz pomieszczeń i w strefie klimatycznej, w której leży nasz kraj) powodują, że stały się one potencjalną alternatywą dla dotychczasowej generacji fotoogniw krzemowych. O wysokim i realnym znaczeniu fotoogniw barwnikowych świadczy lawinowo wzrastająca liczba publikacji i patentów na ich temat oraz wiele prestiżowych nagród naukowych przyznanych w ostatnich latach ich głównemu twórcy, Michealowi Grätzelowi. Separacja ładunku w fotoogniwach barwnikowych decyduje o ogólnej sprawności ogniwa i odbywa się w kilku procesach (wstrzykiwanie elektronu z barwnika do nanocząstki, regeneracja barwnika, transport ładunku przez nanocząstki), których skala czasowa rozciąga się od dziesiątek femtosekund do setek milisekund. Poznańie cząstkowych wydajności poszczególnych procesów jest możliwe za pomocą technik czasowo-rozdzielczej absorpcyjnej i emisyjnej spektroskopii laserowej w świetle widzialnym i podczerwieni. Podczas seminarium omówione zostaną najnowsze modele opisujące wspomniane procesy i zaprezentowane będą wyniki badań fotoogniw barwnikowych metodami spektroskopii laserowej, w których w ostatnich kilku miesiącach autor brał udział. Znaczna część badań została przeprowadzona na Wydziale Fizyki UAM.

Abstract: The talk presents several devices capable of detection of ultra-weak light signals. The main technological aspects and limitations of these devices are discussed with emphasis on possible usage in quantum optical experiments.

Abstract: Controlled phase gate is one of the fundamental building blocks of quantum information devices. This talk presents our experimental implementation of such device and related research.

Abstract: Radiation generated in spontaneous parametric down-conversion exhibits a number of interesting features. One of them is the phenomenon of non-local dispersion cancellation, in which strong temporal correlations between photon pairs are preserved despite propagation through dispersive media with group velocity dispersion coefficients of equal strength and opposite signs. An intriguing question is whether such features can be reproduced with classical radiation. In the case of non-local dispersion cancellation, an analogous effect can be shown to occur also for Gaussian mixtures of coherent states, but at the cost of introducing a uniform background of coincidence counts with a comparable magnitude. We present here a simple variance-based criterion identifying a feature of non-local dispersion cancellation that critically depends on the presence of entanglement in the propagating light. Analogous analysis can be applied also to directional correlations in free-space propagation.

Abstract: We describe a proof-of-principle experiment which shows that quantum cloning can be used for hacking quantum key distribution protocols. We analyze the conditions under which the cloning attack is successful and obtain the corresponding error rates.

Abstract: An alternative approach to implement quantum entangling gates to the well-known linear-optical one is using nonlinear materials for deterministic nonlinear photon interactions. However only small conditional phase shift induced by a few photons in the Kerr nonlinearity was successfully measured. We show how to improve the phase-shift obtained for two single-photon states in the cross-Kerr interaction.

Abstract: Various types of decay for entanglement obtained within nonlinear quantum scissors systems are discussed. Conditions for observing entanglement death or its revival are presented.

Abstract: Several models involving nonlinear quantum Kerr-like oscillators are presented. Such models referred to as nonlinear quantum scissors can lead to finite-dimensional states generation, including maximally entangled ones.

Abstract: Drawing on an analogy with the powerful technique of composite pulses in quantum optics and polarization optics we present a broadband optical diode (optical isolator) made of a sequence of ordinary 45° Faraday rotators sandwiched with quarter-wave plates rotated at the specific angles with respect to their fast polarization axes.

Abstract: Thermoelectric effects in a double quantum dot system coupled to external magnetic/nonmagneticleads are investigated theoretically. The basic thermoelectric transport characteristics, like thermopower, electronic contribution to heat conductance, and the corresponding figure of merit, have been calculated in terms of the linear response theory and Green function formalism in the Hartree-Fock approximation for Coulomb interactions. An enhancement of the thermal efficiency (figure of merit ZT) due to Coulomb blockade has been found. The magnitude of ZT is further considerably enhanced by quantum interference effects. The influence of spin-dependent transport on the thermoelectric effects (especially on Seebeck and spin Seebeck effects) is also analyzed.

Abstract: Recently proposed estimators for entanglement entropy in quantum spin systems in resonating valence bond (RVB) basis are reviewed. Some of them may be effectively calculated by using Monte Carlo techniques. Additionally properties of entanglement spectrum of small systems are presented in position and momentum space and their relation to topologically ordered states is discussed. An attempt to calculate such a spectrum of small spin systems in RVB basis is reported. A possibility of finding the topological order in quantum spin systems using RVB basis is discussed.

Abstract: A primer on how geometric invariant theory and momentum map geometry could be used to effectively find all stochastic local operations and classical communication (SLOCC) classes of pure states.

Abstract: Quantum bipartite states with the direct accessible, ideal cryptographic key are known as private states. In this talk we will present a novel property, namely the invariance of distillable key under rotations around private axis in Devetak-Winter protocol, for general private states. Its application to the problem of searching optimal measurement basis for a given private state will be demonstrated. We will also provide results concerning error estimation of the proposed procedure.

Abstract: It is known that dipolar interactions in the presence of a resonant magnetic field can transfer atoms to higher excited states with non zero angular momentum (Einstein-de Haase effect). We investigate how this effect is modified by the lattice potential. In particular we explain in details the role of anharmonicity and anisotropy of a single lattice site.

Abstract: The talk shows that non-maximally entangled states can be better for atomic state teleportation performed via cavity decay. The destructive influence of cavity decay on the fidelity can be minimized by using in the teleportation the non-maximally entangled states instead of the maximally entangled state.

Abstract: Review of statistical randomness tests and their software implementations used to verify quality of random number generators.

Abstract: The talk presents the perfect state transfer (PST) protocols performed in 1D qubit or qudit chains. Dynamics of transfer is determined by the XY-like Hamiltonian which will be described by special unitary group operators SU(d).

Abstract: We derive an hcp compressible Ising Hamiltonian with a spin-phonon interaction and compute the influence of spin correlations on the empirically observed Brillouin shift. The spin correlations are found by an Oguchi-like method which is newly tailored variation of the Bethe-Peierls-Weiss (BPW) approximation. In the direct space, we consider a cluster consisting of a central spin and its 12 nearest neighbours. Each of the 12 nn pairs, consisting of the central spin and, in turn, all the neighbours , is treated exactly (Oguchi method) while the influence of the remaining spins is replaced by an effective field. In the present approach, the latter is not calculated self-consistently, but substituted by that found in the conventional MFA. In the reciprocal lattice, after the Fourier transformation, we finally arrive at the spin correlation which is temperature and wave-vector dependant. The result remains valid both in the ordered and disordered phases. In the ordered phase, the molecular-field approximation is extended to the static soliton theory.

Abstract: Spatial and spectral properties of the pulsed second harmonic generation in a periodically-poled KTP waveguide are analyzed. Experimental results are interpreted using a model based on finite elements method.

Abstract: Photosynthetic reaction centers are pigment-protein complexes containing a chain of electron transfer carriers. A linear electron transfer between these carriers occurs on a wide time-scale spanning from picoseconds to microseconds depending on particular step of the transfer. In the talk, results of experimental studies of one particular step of this electron transfer will be shown. Multiphasic kinetics of this reaction is interpreted in terms of a model in which protein dynamically modulates the rate of the electron transfer with characteristic lifetimes of  ∼ 1 and  ∼ 10 ns.

Abstract: The talk presents the technique of the so-called solid phase synthesis of organic molecules. Its application on synthesis of compounds with potential biological activity is discussed with emphasis on current research at the Department of Organic Chemistry of Palacký University in Olomouc.

Abstract: The space of anyonic harmonic function on a plane admits a deformed Hodge structure. The deformation of the Hodge structure is connected with the fractional statistics. The parameters of the structure are quantum numbers of the system.

Abstract: This talk presents an elegant concept of the effective mass theory applied to the neutral bosons confined in two-dimensional square lattice under synthetic magnetic field. Analytically calculated band structure allows to predict the existence of the massless particles with neutrino like dispersion relation located in the particular points of the momentum space. It will be shown that the Dirac cones contain massless particles whose positions and velocities can be tuned by the external magnetic field giving rise to the exotic properties. The presence of the Hofstadter spectrum in the strongly interacting system of bosons reveals some unexpected behavior of the local effective mass dependence.

Abstract: We analyse the Hubbard model with correlated hopping, at the double occupancy conservation symmetry point, using Hubbard-I approach which describes fractionalised electrons quasiparticles. We obtain description of Mott transitions and the surrounding extremely correlated quantum liquids. The calculations may be relevant for future experiments on optical lattices.

Abstract: We study the extended Bose-Hubbard model describing an ultracold gas of dipolar molecules in an optical lattice, taking into account all on-site and nearest-neighbor interactions, including occupation-dependent tunneling and pair tunneling terms. We show that these terms can destroy insulating phases and lead to novel quantum phases.

Abstract: Review of several experimental implementations of qubit cloners implemented in the Joint Laboratory of Optics in Olomouc is presented. Quality of various implementations is discussed based on obtained clones fidelity.

Abstract: This review talk presents several linear-optical quantum devices suitable for discrete variables quantum information processing. The devices make use of single and bi-photon interference in both bulk and fibre optical setups.

Abstract: Correlated atom pairs are scattered from colliding Bose-Einstein condensates by a process akin to parametric down conversion. I will describe an experiment and its numerical simulation that have shown number-difference squeezing and a violation of the Cauchy-Schwartz inequality. The long term goal is to test Bell inequalities with spatially separated massive particles.

Abstract: Implementation of an arithmetic qubit on the basis of exact Bethe Ansatz eigenstates of a Heisenberg magnetic ring is proposed. It bases on the Galois number field of an appropriate finite extension of rationals.

Abstract: This talk reviews recent experimental activities in the quantum information processing with linear-optics. The most important results over the past three years are presented.

Abstract: Quantum private states are the states that represent perfectly secure bits of secret key. It is known that among quantum private states that are ones that are not maximally entangled. In those cases secret key extraction goes beyond entanglement distillation scheme. The construction of simple observable called quantum privacy witness which allows to correctly detect and qualitatively estimate privacy will be presented. In some cases the observable is experimentally very friendly still providing useful lower bound for secret key entanglement measure K beyond entanglement distillation regime.

Abstract: Evolution of the two-atom system driven by the resonant laser field is considered. It is shown that the two-photon entangled states can be generated in such a system. The role of the dipole-dipole interaction in generating of quantum correlations is discussed. The condition for obtaining steady-state entanglement is given and the time evolution of the quantum correlations is presented.

Abstract: In this lecture, the main concepts of single molecule fluorescence microscopy (SMS) are first explained. Then, I will show and discuss results from my group studying selected molecules interacting with silica based materials where we can directly visualise the photobehavior of a single molecule interacting with this kind of materials. We identify the relevant populations, and assign their emission characteristics.

Abstract: [PDF] 

Abstract: [PDF]  Photo-Induced phase transitions [1-2] pose challenging issues to science and science-driven technologies, the goal of which is to control with light the cooperative switching of the macroscopic physical state of a material. A better understanding of the mechanisms is necessary. Photo-crystallography may be a key issue on that purpose through the different kinds of information that can be obtained from X-Ray diffraction [3] patterns: unit-cell geometries, average atomic positions, symmetry-breaking and order parameter, mechanisms of the transition (nucleation of domains versus homogeneous transformation), coherent processes, etc … A few examples of photo-induced transformations in charge-transfer molecular materials [4] or spin-crossover compounds [5-6], under both continuous or pulsed (down to femtosecond 1 fs = 10⁻¹⁵ s) irradiation will be presented. References:
[1] Cailleau H. et al., Chap. 7 in “Photoinduced Phase Transitions”, ISBN: 981-238-763-3 (2004).
[2] Cailleau H. et al., Acta Phys. Polonica A 121 297 (2012).
[3] Collet E. et al., Journal of the Jap. Phys. Soc. 75 011002 (2006).
[4] Guerin L. et al, Phys. Rev. Lett. 105 246101 (2010).
[5] Lorenc M. et al, Phys Rev. Lett. 103 028301 (2009).
[6] Buron-Le Cointe M. et al, Phys. Rev. B 85 064114 (2012).