BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:On fast charged particles scattering in thin crystalline and amorp hous targets DTSTART;VALUE=DATE-TIME:20191224T141500Z DTEND;VALUE=DATE-TIME:20191224T143500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-121@indico.bitp.kiev.ua DESCRIPTION:Speakers: Viktoriia Koriukina (National Science Center Kharkiv Institute of Physics and Technology\, Kharkiv)\nThe problem of fast charg ed particles scattering in a thin layer of crystalline and amorphous matte r is considered [1]. There is suggested an approach that allows one to con sider the process of scattering in such targets from a single point of vie w. The approach is based on the Born and Eikonal approximations of the qua ntum scattering theory [2]. In the case of scattering in a crystal\, speci al attention is paid to the question of the cross section splitting into c oherent and incoherent components and to the applicability conditions of t he Born and Eikonal approximations for different orientations of the cryst al axes and planes.\n\nReferences\n[1] N.F. Shul'ga\, V.D. Koriukina. The Eikonal Approximation of the Scattering Theory for Fast Charged Particles in a Thin Layer of Crystalline and Amorphous Media. ArXiv preprint arXiv:1 908.00935 (2019)\n[2] A.I. Akhiezer\, N.F. Shul'ga. High Energy Electrodyn amics in Matter. Gordon and Breach Pub. Amsterdam. 1996\n\nhttps://indico. bitp.kiev.ua/event/4/contributions/121/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/121/ END:VEVENT BEGIN:VEVENT SUMMARY:Dark matter signals description in the scattering processes in the generalized Yukawa model DTSTART;VALUE=DATE-TIME:20191224T131500Z DTEND;VALUE=DATE-TIME:20191224T133500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-123@indico.bitp.kiev.ua DESCRIPTION:Speakers: Mykyta Dmytriiev (Oles Honchar Dnipro National Unive rsity)\n$\\qquad$According to present day results of the LHC experiment da ta analysis\, there were no dark matter candidates found. The purpose of t his work is to present a possible theoretical explanation why it could be so.\n$\\qquad$In our consideration\, we propose a simple dark matter model of the heavy fermions described by the field $\\psi$. A visible matter is modeled by the pair of scalar fields – light $\\phi$ and heavy $\\chi$. These fields interact with dark matter through Yukawa’s couplings. Besi des\, there is the doublet of fermions fields $\\psi_1$ and $\\psi_2$ inte racting with $\\phi$ and $\\chi$ with different couplings. The Yukawa mode l is chosen as the simplest one for the interaction carrier\, which allows us to take into consideration the qualitatively important effect of the c oupling constant values. At the same time\, the transformation properties of visible fields are not accounted for as inessential.\n$\\qquad$We start from the Lagrangian:\n\n$$\\begin{align}\n \\mathcal{L} = \\frac{1}{2} \\left[\\left(\\partial_{\\nu}\\phi\\right)^2 - \\mu^2\\phi^2\\right] + \\ frac{1}{2}\\left[\\left(\\partial_{\\nu}\\chi\\right)^2 - \\Lambda^2\\chi^ 2\\right] + \\\\\n +\\sum\\limits_{a=1\;2}\\bar{\\psi}_a\\left(i\\gamma ^{\\nu}\\partial_{\\nu} - g_{\\phi}\\phi - g_{\\chi}\\chi - m\\right)\\psi _a + \\bar{\\Psi}\\left(i\\gamma^{\\nu}\\partial_{\\nu} - M\\right)\\Psi - \\\\\n - \\lambda\\phi^4 + \\rho\\phi^2\\chi^2 - \\xi\\chi^4 - G_{\\ch i}\\bar{\\Psi}\\chi\\Psi. \n\\end{align}$$\n\n$\\qquad$As we see\, fermion s interact with each other via the interchange of scalar particles. It can be considered as the effective four-fermions vertexes. Probability of cer tain scenario of interaction – through $\\phi$ or $\\chi$ field – depe nds on the mixing angle between these two fields. Moreover\, the polarizat ion tensor of $\\chi$ contains also the contribution of the $\\Psi$ fermio n loop. Hence\, the differential cross-section $\\sigma$ of the four-fermi ons interaction depends on the mass of the dark matter particle and the mi xing angle between scalar fields. We set this angle to be equaled $10^{-3} $-$10^{-4}$\, while the mass of $\\Psi$ is much bigger than the mass of $\ \psi_1$ or $\\psi_2$. Because of this\, a cross-section width becomes sign ificant\, so that such a signal can be missed in the data analysis on the LHC as a noise. This is probably because the narrow width approximation is applied in processing of data treating applied by Collaborations. \n$\\qq uad$Taking into account the facts listed above\, the differential cross-se ction of the four-fermion interaction is obtained and its spatial angular dependence is investigated. The renormalisations of the couplings and mass es are fulfilled. We investigate how the $\\sigma$ changes dependently on the $\\Psi$ field mass and the mixing angle of scalar fields. Process $\\b ar{\\psi}_1\\psi_1\\rightarrow\\bar{\\psi}_2\\psi_2$ is considered. \n\nA.  Gulov\, A. Kozhushko\, V. Skalozub. Global search for the Z' boson in scattering processes ‑ Днiпро: ЛIРА\, 2018. ‑ 124 с.\n\nhttps ://indico.bitp.kiev.ua/event/4/contributions/123/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/123/ END:VEVENT BEGIN:VEVENT SUMMARY:Towards understanding of condensed matter via study granular syste ms DTSTART;VALUE=DATE-TIME:20191223T144500Z DTEND;VALUE=DATE-TIME:20191223T150500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-147@indico.bitp.kiev.ua DESCRIPTION:Speakers: Andrii Spivak (Odesa State Environmental University) \nGranular materials under the external perturbations show a diversity of structural transformations which characterized by different symmetries. Th eir rigorous classification in terms of phase transitions seems very attra ctable (nevertheless\, still questionable). Intriguing question is: can we use the information extracted from studying of structural transformations characters in granular materials to describe any details about the local symmetry of the condensed matter\, which displayed during the typical phas e–transformations? Here\, there are several analogies as well as discrep ancies are waiting for us: Local structure\, Phase transitions\, Landau-Gi nzburg kinetics\, Lindeman criteria for crystallization\, Equation of stat e.\n$~~~~~~$We would like to outline some results of our research directed to study of structurization\, which occurs during packing processes in ge ntly agitated granular (micro-mechanical) systems [1-5]. The focus will be done on developing and investigation of hard-spheres (discs) packing mode ls. The results of this research\, in our opinion\, in principle can provi de an understanding of some characters of the local structure and bulk pro perties not only of granular matter\, but also a regular phases of condens ed matter (e.g.\, molecular liquids and solutions\, colloids\, glasses). T he problem of densest packing are formally belong to pure mathematical are a. But inspite of this objectives to study structural and physical propert ies of perturbed granular systems a variety of physical theoretical model s which are partially based on phenomenological information (direct observ ation) have been developed. The packing of hard-particles can be described by geometric approach\, which provides a practical and universal methods of quantitative characterization of the local (as well as global) packing via symmetry categories.\n$~~~~~~$We will consider a packing of a large co nglomeration of hard particles confined by a finite-sized container. Bound aries as well as exclusion-volume effects (under the negligible dissipatio n) would be described by simple packing parameters (like compactivity). Pr operties of the states of such systems (for instance 2D hard discs) will b e studied theoretically and after then compared with the results of direct observations. Obtained results will be analyzed with respect to reminisce nces with some properties of the typical phases of condensed matter.\n\n[1 ]. Gerasimov O.I.\, Idomskyy V.A.\, Schram P.P.-J.M. Compaction of granula r graphite in a vertically vibrating container with restricted geometry. C ondens. Matter Phys. 4 (1)\, 161-164 (2001). DOI: https://doi.org/10.5488/ CMP.4.1.161\n[2]. Gerasimov O.I.\, Schram P.P.-J.M. Differential equation of state of a model system with a singular measure: application to granula r materials in steady states. Physica A 312 (1-2)\, 172-180 (2002). DOI: h ttps://doi.org/10.1016/S0378-4371(02)00851-8\n[3]. Gerasymov O.I.\, Zagoro dny A.G.\, Somov M.M. Toward the Analysis of the Structure of Granular Mat erials. Ukr. J. Phys. 58 (1)\, 32-39 (2013). DOI: https://doi.org/10.1540 7/ujpe58.01.0032\n[4]. Gerasymov O.I.\, Spivak A.Ya. Kinetic model of comp action in granular materials. Ukr. J. Phys. 60 (3)\, 253-257 (2015). DOI: https://doi.org/10.15407/ujpe60.03.0253\n[5]. Schockmel J.\, Vandewalle N. \, Opsomer E.\, Lumay G. Frustrated crystallization of a monolayer of magn etized beads under geometrical confinement. Phys. Rev. E 95 (6)\, 062120 (2017). DOI: https://doi.org/10.1103/PhysRevE.95.062120\n\nhttps://indico. bitp.kiev.ua/event/4/contributions/147/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/147/ END:VEVENT BEGIN:VEVENT SUMMARY:Second look to the Polyakov Loop Nambu-Jona-Lasinio model at finit e baryonic density DTSTART;VALUE=DATE-TIME:20191224T121500Z DTEND;VALUE=DATE-TIME:20191224T123500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-119@indico.bitp.kiev.ua DESCRIPTION:Speakers: Oleksii Ivanytskyi (Bogolyubov Institute for Theoret ical Physics of the National Academy of Sciences of Ukraine\, Kyiv)\nWe re visit the Polyakov Loop coupled Nambu-Jona-Lasinio model that maintains th e Polyakov loop dynamics in the limit of zero temperature\, which is of in terest for astrophysical applications. For this purpose we re-examine the form of the potential for the deconfinement order parameter at finite bary onic densities. Secondly\, and the most important\, we explicitly demonstr ate that a modification of this potential at any temperature is formally e quivalent to assigning a baryonic charge to gluons. In order to avoid this spurious effect we develop a more general formulation of the present mode l that cures this defect and is normalized to match the asymptotic behavio ur of the QCD equation of state given by $\\mathcal{O}(\\alpha_s^2)$ and p artial $\\mathcal{O}(\\alpha_s^3\\ln^2\\alpha_s)$ perturbative results.\n\ nhttps://indico.bitp.kiev.ua/event/4/contributions/119/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/119/ END:VEVENT BEGIN:VEVENT SUMMARY:Quantum antiferromagnet in a magnetic field on frustrated kagome- lattice bilayer DTSTART;VALUE=DATE-TIME:20191223T101500Z DTEND;VALUE=DATE-TIME:20191223T103500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-118@indico.bitp.kiev.ua DESCRIPTION:Speakers: Vasyl Baliha (Institute for Condensed Matter of the National Academy of Sciences of Ukraine\, Lviv)\nWe consider the spin-1/2 antiferromagnetic isotropic Heisenberg model on a kagome-lattice bilayer i n the presence of an external magnetic field. We include an interlayer fru stration term and study the case of ideal frustration when the nearest-nei ghbor intralayer interactions and the frustrating interlayer interactions are of the same strength. In this case\, a completely dispersionless (flat ) magnon band may become the lowest-energy one and we can use the localize d-magnon picture to examine the system in more simple terms. In the vicini ty of the saturation field\, we map the low-energy states of the considere d quantum system onto the spatial configurations of hard parallelograms on an auxiliary kagome lattice and face a much simpler problem of classical statistical mechanics. It allows us to construct an effective model and st udy the low-temperature thermodynamic properties of the original quantum m odel. Also\, an effective model was constructed using perturbation theory. \n\nhttps://indico.bitp.kiev.ua/event/4/contributions/118/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/118/ END:VEVENT BEGIN:VEVENT SUMMARY:Localized waves and resonance effects in layered superconductors DTSTART;VALUE=DATE-TIME:20191223T085500Z DTEND;VALUE=DATE-TIME:20191223T091500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-148@indico.bitp.kiev.ua DESCRIPTION:Speakers: Dmytro Kadygrob (A.Ya. Usikov Institute for Radiophy sics and Electronics National Academy of Sciences of Ukraine\, Kharkov\, Ukraine\\ V.N. Karazin Kharkov National University\, Kharkov\, Ukraine)\nH igh-temperature superconductors with layered structure\, such as $\\rm YBa _2 Cu_3 O_{7-\\delta}$\,$\\rm Bi_2Sr_2CaCu_2O_{8+\\delta}$\, $\\rm La_{2-\ \delta}Sr_\\delta CuO_4$ are anisotropic and strongly nonlinear Josephson plasma media. Such layered superconductors favor propagation of electromag netic waves in the THz frequency range which is promising for various appl ications. In close analogy to nonlinear optics\, these materials exhibit n umerous remarkable features\, including the self-focusing effects\, slowin g down of light\, stimulated transparency etc. Furthermore\, layered super conductors possess anisotropy with simultaneously different signs of the p ermittivity tensor components in a certain frequency range\, providing a p ossibility of negative index of refraction and hyperbolic dispersion law [ 1].\n$~~~~~~$In this work\, a series of recent theoretical studies of the propagation of localized Josephson plasma waves (JPW) in layered supercond uctors is discussed. In particular\, the propagation of JPWs along the bou ndaries of semi-infinite samples and along a plate of finite thickness are studied. We show that when the layers are perpendicular to the plate boun daries\, the anomalous dispersion of the localized waves is predicted for layered superconductors in a certain range of frequencies and wave numbers [2]. In addition\, due to nonlinearity one can control the anomalous disp ersion of the spectrum by the wave amplitude [3].\n$~~~~~~$We also present new results on excitation and propagation of localized Josephson plasma w aves in a plate of layered superconductor in the presence of an external s tatic magnetic field. For this case\, the dispersion equations for localiz ed waves in the plate of layered superconductor are obtained. It turns out that even relatively weak static magnetic field can significantly change the conditions for the waves propagation [4]. Also\, we study THz transmis sion through layers and show that the resonance transmission of JPWs can b e flexibly tuned by the DC magnetic field in a wide range of the parameter s. The studied resonant phenomenon opens wide prospects for possible appli cations\, such as THz waves filtering or tuning the emission and receive f requency from THz sources.\n$~~~~~~$The publication contains the results o f studies conducted by Presidents of Ukraine grant for competitive project s (F82/233-2019)\, which support we gratefully acknowledge.\n\n[1]. A.L. R akhmanov\, V.A. Yampol'skii\, J.A. Fan\, F. Capasso\, and Franco Nori\, Ph ys. Rev. B 81\, 075101 (2010).\n[2]. S.S. Apostolov\, Z.A. Maizelis\, D.V . Shimkiv\, A.A. Shmat'ko\, V.A. Yampol'skii\, Low Temp. Phys. 45\, 885 ( 2019).\n[3]. S.S. Apostolov\, D.V. Kadygrob\, Z.A. Maizelis\, A.A. Nikolae nko\, V.A. Yampol'skii\, Low Temp. Phys. 44(3)\, 238 (2018).\n[4]. T. Ro khmanova\, S.S. Apostolov\, N. Kvitka\, V.A. Yampol'skii\, Low Temp. Phys. 44\, 552 (2018).\n\nhttps://indico.bitp.kiev.ua/event/4/contributions/148 / LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/148/ END:VEVENT BEGIN:VEVENT SUMMARY:Relaxation in classical integrable systems DTSTART;VALUE=DATE-TIME:20191224T113000Z DTEND;VALUE=DATE-TIME:20191224T121500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-162@indico.bitp.kiev.ua DESCRIPTION:Speakers: Oleksandr Gamayun (University of Amsterdam)\nhttps:/ /indico.bitp.kiev.ua/event/4/contributions/162/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/162/ END:VEVENT BEGIN:VEVENT SUMMARY:The verification of Machine Learning methods for binary morphologi cal classification of SDSS-galaxies DTSTART;VALUE=DATE-TIME:20191224T085500Z DTEND;VALUE=DATE-TIME:20191224T091500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-127@indico.bitp.kiev.ua DESCRIPTION:Speakers: Daria Dobrycheva (Main Astronomical Observatory of t he National Academy of Sciences of Ukraine)\nClassification of galaxy type s is one of the cornerstones for extragalactic astrophysics and observatio nal cosmology. The most precise method of galaxy classification used by as tronomers so far is the manual classification. Its major drawback\, howeve r\, is the extensive usage of manpower\, either from highly skilled profes sionals\, or\, in some cases (such as in Galaxy Zoo project) amateur astro nomers. Modern or forthcoming galaxy surveys (SDSS\, LSST\, DES\, KiDS\, e tc.) are able to detect hundreds of millions of galaxies\, impossible to c lassify manually. This exaggerates the interest to use the alternatives in form of various recently developed Machine Learning (including Deep Learn ing) techniques for automated classification of galaxies.\n\nWe present a study on the verification of Machine Learning (ML) methods to be applied f or binary morphological classification of galaxies ($E$ - Early and $L$ - Late types). We used two kinds of supervised learning techniques: the firs t is classical machine learning classifiers\, and the second is deep convo lutional neural network classifier.\n\nWe want to emphasize that\, unlike most other authors\, we paid attention to the visual cleaning of the datas et. Our dataset contains of $\\sim$ 300 000 SDSS-galaxies from DR9 with un known morphological types at $z\n\nhttps://indico.bitp.kiev.ua/event/4/con tributions/127/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/127/ END:VEVENT BEGIN:VEVENT SUMMARY:The Aharonov-Bohm effect and conic singularities for the Dirac equ ation DTSTART;VALUE=DATE-TIME:20191223T160500Z DTEND;VALUE=DATE-TIME:20191223T161000Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-154@indico.bitp.kiev.ua DESCRIPTION:Speakers: Eduard Naichuk (Taras Shevchenko National University of Kyiv )\nThe solution of the problem of fermions scattering in one Ahar onov-Bohm vortex involves constructing a one-parameter family of self-adjo int extensions. The Green function can be constructed from the correspondi ng solutions. The following is a comparison of quantum-mechanical scatteri ng problem with quantum field theory problem on the search for correlation functions of fermion states. Namely\, Green's function can be interpreted as correlation function in the space of fermion states. Also there is con sidered a similar problem about scattering of fermions on a conical singul arity\, which implies a similar analysis of the results.\n\nhttps://indico .bitp.kiev.ua/event/4/contributions/154/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/154/ END:VEVENT BEGIN:VEVENT SUMMARY:Spontaneous and engineered transformations of topological structur es in nonlinear media with gain and loss DTSTART;VALUE=DATE-TIME:20191223T155000Z DTEND;VALUE=DATE-TIME:20191223T155500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-116@indico.bitp.kiev.ua DESCRIPTION:Speakers: Oksana Chelpanova (Taras Shevchenko National Univers ity of Kyiv)\nIn contrast to conservative systems\, in nonlinear media wit h gain and loss the dynamics of localized topological structures exhibit m any unique features that can be controlled externally. We propose a robust mechanism to perform topological transformations changing characteristics of dissipative vortices and their complexes in a controllable way. We sh ow that a properly chosen control carries out the evolution of dissipative structures to regime with spontaneous transformation of the topological e xcitations or drives generation of vortices with control over the topologi cal charge.\n\nhttps://indico.bitp.kiev.ua/event/4/contributions/116/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/116/ END:VEVENT BEGIN:VEVENT SUMMARY:New bounds on axion-like particles from NuSTAR observations DTSTART;VALUE=DATE-TIME:20191223T161000Z DTEND;VALUE=DATE-TIME:20191223T161500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-126@indico.bitp.kiev.ua DESCRIPTION:Speakers: Denys Savchenko (Bogolyubov Institute for Theoretica l Physics of the National Academy of Sciences of Ukraine\, Kyiv)\nAxions a re hypothetical particles beyond the Standard Model. Their existence is po stulated to resolve the strong CP problem in QCD. The existence of the axi on-like particles should modify the visible spectra of the cosmic objects due to their coupling to photons in the presence of a magnetic field\, for example\, inside galaxy clusters. For this reason\, they were proposed as one of the explanations for the inconsistencies between Hitomi and Chandr a observations of the 3.5 keV line in Perseus cluster. Furthermore\, axion -like particles could constitute the cold dark matter itself.\nIn this tal k\, we present the upper bounds on the axion-photon coupling from non-dete ction of imprints of such coupling in the NuSTAR observations of the NGC12 75 galaxy\, embedded in the Perseus galaxy cluster.\n\nhttps://indico.bitp .kiev.ua/event/4/contributions/126/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/126/ END:VEVENT BEGIN:VEVENT SUMMARY:Hunting the dark matter origin with astrophysical and cosmological data DTSTART;VALUE=DATE-TIME:20191224T073000Z DTEND;VALUE=DATE-TIME:20191224T081500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-128@indico.bitp.kiev.ua DESCRIPTION:Speakers: Dmytro Iakubovskyi (Bogolyubov Institute for Theoret ical Physics)\n.\n\nhttps://indico.bitp.kiev.ua/event/4/contributions/128/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/128/ END:VEVENT BEGIN:VEVENT SUMMARY:Static and slowly rotating three-dimensional black hole in nonline ar electrodynamics DTSTART;VALUE=DATE-TIME:20191224T101500Z DTEND;VALUE=DATE-TIME:20191224T103500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-129@indico.bitp.kiev.ua DESCRIPTION:Speakers: Mykhailo Tataryn (Department for Theoretical Physics \, Ivan Franko National University of Lviv)\nThree-dimensional electricall y charged black hole with nonlinear electromagnetic field in anti-de Sitte r spacetime is studied. Both static [1] and slowly rotating cases are cons idered. Solutions of field equations are obtained and thermodynamic behavi or in extended phase space thermodynamics is examined.\n\n[1] M. B. Tatary n\, M. M. Stetsko\, Int. J. Mod. Phys. D 28 (2019) 1950160.\n\nhttps://ind ico.bitp.kiev.ua/event/4/contributions/129/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/129/ END:VEVENT BEGIN:VEVENT SUMMARY:Mathieu equation as a confluent Heun equation and its applications DTSTART;VALUE=DATE-TIME:20191223T160000Z DTEND;VALUE=DATE-TIME:20191223T160500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-158@indico.bitp.kiev.ua DESCRIPTION:Speakers: O.V. Yanchyshen (Kyiv Academic University)\nMathieu equation appears in different fields of physics and usually it's known as Schrodinger equation with cosine as potential but in more general sense it's a certain specification of confluent Heun equation. Heun equation i s a second order ordinary differential equation with rational coefficients \, with four regular singular points. Without loss of generality we can pu t these points in $1\, 0\, t\, \\infty$. In our work we consider Mathieu equation and confluent Heun equations and their connection with classical conformal blocks.\n\nhttps://indico.bitp.kiev.ua/event/4/contributions/15 8/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/158/ END:VEVENT BEGIN:VEVENT SUMMARY:Topological magnetic solitons in curvilinear nanomagnets DTSTART;VALUE=DATE-TIME:20191223T073000Z DTEND;VALUE=DATE-TIME:20191223T081500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-160@indico.bitp.kiev.ua DESCRIPTION:Speakers: V.P. Kravchuk (Bogolyubov Institute for Theoretical Physicsof the National Academy of Sciences of Ukraine\, Kyiv)\nhttps://ind ico.bitp.kiev.ua/event/4/contributions/160/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/160/ END:VEVENT BEGIN:VEVENT SUMMARY:Equation of state from lattice QCD at imaginary chemical potential and external magnetic field DTSTART;VALUE=DATE-TIME:20191224T123500Z DTEND;VALUE=DATE-TIME:20191224T125500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-134@indico.bitp.kiev.ua DESCRIPTION:Speakers: Natalia Kolomoyets (Joint Institute for Nuclear Rese arch\, Dubna\, Russia)\nThis report is devoted to lattice study of QCD equ ation of state (EOS) at finite baryon chemical potential and nonzero magn etic field. The simulations are performed with rooted dynamical staggered $u$\, $d$\, $s$ quarks at physical quark masses. In order to avoid the sig n problem\, the study is carried out at imaginary chemical potential and t he results are analytically continued to real chemical potential. In this report we present our preliminary results for the pressure and energy den sity for various values of temperature\, chemical potential and magnetic f ield.\n\nhttps://indico.bitp.kiev.ua/event/4/contributions/134/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/134/ END:VEVENT BEGIN:VEVENT SUMMARY:The electroweak phase transition and spontaneous creation of magne tic fields DTSTART;VALUE=DATE-TIME:20191224T125500Z DTEND;VALUE=DATE-TIME:20191224T131500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-130@indico.bitp.kiev.ua DESCRIPTION:Speakers: Pavlo Minaiev (Oles Honchar Dnipro National Universi ty)\nThere were many phase transitions during the evolution of our Univers e. The electroweak phase transition and deconfinement were two of them. Th e electroweak phase transition happened near 100 GeV and due to Higgs mech anism the leptons\, quarks and gauge bosons gained mass. The deconfinement phase transition happened near 150 MeV and quarks combined to each other\ , as a result baryons and mesons were created. In QCD and gluodynamics the color chromomagnetic fields $B_3$ and $B_8$ are created spontaneously at temperature $T > T_d$ higher than the deconfinement temperature $T_d$. Usu al magnetic field $H$ had also been spontaneously generated because of qua rks loop. The quarks possess electric and color charges\, as a result magn etic and chromomagnetic fields are mixing in effective potential. These fi elds appear spontaneously for $T > T_d$ and they were present for temperat ure near critical temperature of the electroweak phase transition. For $T$ close to $T_{EW}$ the magnetic fields could change the type of the phase transition.\nWe investigate the electroweak phase transition in the Standa rd Model with accounting the spontaneously generated magnetic and chromoma gnetic fields. As it is known\, for the mass of Higgs boson greater than 7 5 GeV this phase transition is second order. But according to Sakharov's c onditions for the formation of the baryon asymmetry of the Universe it has to be strongly first order. The spontaneously generated (chromo) magnetic fields are temperature dependent. They influence the phase transition. Th e strength of generated fields and the critical temperature of phase trans ition are also estimated.\n\nhttps://indico.bitp.kiev.ua/event/4/contribut ions/130/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/130/ END:VEVENT BEGIN:VEVENT SUMMARY:Effective description of the frustrated Heisenberg three-leg and f our-leg tubes in a strong magnetic field DTSTART;VALUE=DATE-TIME:20191223T095500Z DTEND;VALUE=DATE-TIME:20191223T101500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-117@indico.bitp.kiev.ua DESCRIPTION:Speakers: Olesia Krupnitska (Institute for Condensed Matter Ph ysics of the National Academy of Sciences of Ukraine\, Lviv)\nWe investiga te the low-temperature properties of the spin-1/2 antiferromagnetic Heisen berg model on the frustrated three-leg [1-2] and four-leg [3-5] tubes with almost dispersionless (almost flat) lowest magnon band placed in an exter nal magnetic field. The aim of our study is to develop a systematic theory of low-temperature high-field properties of the models by hand. Using sta ndard operator perturbation theory and strong coupling approach\, we const ruct low-energy effective Hamiltonians for three-leg and four-leg tubes\, which are much simpler than the initial ones. Based on the effective-model description we examine the low-temperature properties of the considered f rustrated quantum Heisenberg antiferromagnets in the high-field regime. To verify the region of the applicability of the obtained effective Hamilton ians we perform extensive exact diagonalization and density matrix renorma lization group calculations and compare them with the results for the init ial models.\n\n[1] M. Maksymenko\, O. Derzhko and J. Richter\, Acta Physic a Polonica A **119**\, 860 (2011)\; Eur. Phys. J. B **84**\, 397 (2011).\n \n[2] J.-B. Fouet\, et al.\, Phys. Rev. B **73**\, 014409 (2006).\n\n[3] R . Jafari\, et al.\, Journal of Physics: Condensed Matter **31**\, 495601 ( 2019).\n\n[4] F.A. Albarracin\, et al.\, Phys. Rev. B **90**\, 17 (2014).\ n\n[5] M. Arlego\, et al.\, Phys. Rev. B **87**\, 014412 (2013).\n\nhttps: //indico.bitp.kiev.ua/event/4/contributions/117/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/117/ END:VEVENT BEGIN:VEVENT SUMMARY:Scalar field dark matter with $\\phi^6$ self-interaction DTSTART;VALUE=DATE-TIME:20191224T095500Z DTEND;VALUE=DATE-TIME:20191224T101500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-137@indico.bitp.kiev.ua DESCRIPTION:Speakers: Mariia Khelashvili (Bogolyubov Institute for Theoret ical Physics of the National Academy of Sciences of Ukraine\, Kyiv)\nThe u ltralight dark matter (ULDM) model proposes as DM particles candidates bos ons with typical mass $10^{-22}$ eV\, such that its de Broglie wavelength is of galactic scale ($\\sim$kpc). The ULDM was among the models\, that we re proposed to resolve CDM tensions on the small scales\, such as core-cus p and missing satellite problem. However last times it faces some difficul ties between observed spiral galaxies rotation curves and the model’s pr edictions\, if one takes into account core/host halo mass relation and the relation between mass and radius of a central core\, that follows from si mulations. In the present work\, we consider complex scalar field minimall y coupled to gravity with $\\phi^6$ self-interaction potential. We will d iscuss this model’s predictions including DM density distribution in the galactic halo and its potential regarding solving the above-mentioned pro blems.\n\nhttps://indico.bitp.kiev.ua/event/4/contributions/137/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/137/ END:VEVENT BEGIN:VEVENT SUMMARY:Embedded solitons in the double sine-Gordon lattice with next-neig hbor interaction DTSTART;VALUE=DATE-TIME:20191223T083500Z DTEND;VALUE=DATE-TIME:20191223T085500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-114@indico.bitp.kiev.ua DESCRIPTION:Speakers: Ivan O. Starodub (Bogolyubov Institute for Theoretic al Physics of the National Academy of Sciences of Ukraine\, Kyiv)\nTopolog ical solitons under certain conditions can freely propagate without radiat ion in the discrete systems of Josephson junctions [1]. These solutions ar e known as embedded solitons [2]. The dynamics of soliton in the array of the small Josephson junctions which contain a ferromagnet (SFS\, SFIS) in their structure and where the intercell inductance is taken into account i s investigating. For such junctions the current-phase relation is complica ted and the second harmonic must be considered. The possibility of embedde d solitons existence in the array\, where the inductive coupling between c ells occurs not only between the nearest neighbors\, but also with the sub sequent ones is demonstrated [3]. These interactions can be either destruc tive or favorable for the embedded solitons creation. The equation of soli ton motion in the array with long-range interaction is analytically obtain ed\, the dispersion law for Josephson plasmons which essentially depends o n the inductive interaction between the adjacent cells of the array is fou nd. The simulation of soliton dynamics in such system performed\, the rang e of system parameters and the set of velocities at which the embedded sol itons existence is possible are obtained. The existence area is inversely proportional to the spectrum width of the linear waves that producing due to the soliton motion across the array. The influence of the array cells i nteraction parameters on the mode of the soliton free propagation is analy zed and the dependence of its velocity on these parameters is found. The c urrent-voltage characteristics of the array with the signs of embedded sol itons existence are constructed. The inaccessible voltage interval is form ed on it\, the upper edge of this interval is proportional to the sliding velocity of the embedded soliton and its size depends on the dissipation i n the system.\n\n[1]. M.Peyrard and M.D. Kruskal\, Physica D 14\, 88 (1984 ).\n[2]. A. Champneys\, B. Malomed\, J. Yang and D. Kaup\, Physica D 152-1 53\, 340 (2001)\n[3]. Yaroslav Zolotaryuk and Ivan O. Starodub\, Physical Review E 100\, 032216 (2019)\n\nhttps://indico.bitp.kiev.ua/event/4/contri butions/114/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/114/ END:VEVENT BEGIN:VEVENT SUMMARY:Symmetry breaking in weak- and strong- coupled ring-shaped superfl ows of Bose--Einstein condensates DTSTART;VALUE=DATE-TIME:20191223T153500Z DTEND;VALUE=DATE-TIME:20191223T154000Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-122@indico.bitp.kiev.ua DESCRIPTION:Speakers: Artem Oliinyk (Department of Physics\, Taras Shevche nko National University of Kyiv)\nOne of the most remarkable manifestation s of quantum properties of superconductors and superfluids is formation of Josephson vortices (JVs)\, alias fluxons\, in long Josephson junctions.\n In this work\, we studied weak- and strong-coupled systems of two parallel superfluid rings with different angular momenta. Atomic Bose-Einstein con densates loaded in a dual-ring trap (two rings separated by a horizontal p otential barrier) suggest a possibility to consider the tunneling dynamics . \nOur research corresponds with investigation of tunneling influence on dynamics of coupled ring-shaped systems of superflows by numerical simulat ions in framework of weakly dissipative mean-field model.\nIn case of weak -coupling\, symmetry breaking suggests Josephson vortex nucleation between the superflows with different angular momenta in low density area. \nIn c ase of strong-coupling (when the barrier is gradually eliminated)\, we obs erved the following situation: the JVs accumulate more and more energy and there is substantially 3D dynamics of vortices. We describe dynamics of c ounter-rotating superflows with and without axial symmetry breaking. It is demonstrated that the population imbalance between the merging flows and the breaking of the underlying rotational symmetry can drive the double-ri ng system to final states with different angular momenta.\n\nhttps://indic o.bitp.kiev.ua/event/4/contributions/122/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/122/ END:VEVENT BEGIN:VEVENT SUMMARY:New mass bound on fermionic dark matter from a combined analysis o f classical dSphs DTSTART;VALUE=DATE-TIME:20191224T081500Z DTEND;VALUE=DATE-TIME:20191224T083500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-125@indico.bitp.kiev.ua DESCRIPTION:Speakers: Denys Savchenko (Bogolyubov Institute for Theoretica l Physics of the National Academy of Sciences of Ukraine\, Kyiv)\nDwarf sp heroidal galaxies (dSphs) are the most compact dark-matter-dominated objec ts observed so far. The Pauli exclusion principle limits the number of fer mionic dark matter particles that can compose a dSph halo. This results in a well-known lower bound on their particle mass. So far\, such bounds wer e obtained from the analysis of individual dSphs. We model dark matter hal o density profiles via the semi-analytical approach and analyse for the fi rst time the data from eight ‘classical’ dSphs assuming the same mass of dark matter fermion in each object. We obtain a new 2σ lower bound of m ≳ 190 eV on the dark matter fermion mass. Besides\, by combining a sub -sample of four dSphs – Draco\, Fornax\, Leo I\, and Sculptor – we con clude that 220 eV fermionic dark matter appears to be preferred over the s tandard cold dark matter at about 2σ level. However\, this result becomes insignificant if all seven objects are included in the analysis.\n\nhttps ://indico.bitp.kiev.ua/event/4/contributions/125/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/125/ END:VEVENT BEGIN:VEVENT SUMMARY:Dark-matter admixed compact stars and their properties under extre me conditions DTSTART;VALUE=DATE-TIME:20191224T093500Z DTEND;VALUE=DATE-TIME:20191224T095500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-124@indico.bitp.kiev.ua DESCRIPTION:Speakers: Violetta Sagun (University of Coimbra\, Portugal/ Bo golyubov Institute for Theoretical Physics National Academy of Sciences of Ukraine\, Kyiv)\nWe study an impact of asymmetric dark matter on properti es of the neutron stars and their ability to reach the two solar masses li mit\, which allows us to present a new upper constraint on the mass of dar k matter particle. Our analysis is based on the observational fact of exis tence of three pulsars reaching this limit and on the theoretically predic ted reduction of the neutron star maximal mass caused by accumulation of d ark matter in its interior. Using modern data on spatial distribution of b aryon and dark matter in the Milky Way we argue that particles of dark mat ter can not be heavier than 5 GeV. We also demonstrate that light dark mat ter particles with masses below 0.2 GeV can create an extended halo around the neutron star leading not to decrease\, but to increase of its visible gravitational mass. Furthermore\, we predict that high precision measurem ents of the neutron stars maximal mass near the Galactic center will put a stringent constraint on the mass of the dark matter particle. This last r esult is particularly important to prepare ongoing\, and future radio and X-ray surveys.\n\nhttps://indico.bitp.kiev.ua/event/4/contributions/124/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/124/ END:VEVENT BEGIN:VEVENT SUMMARY:Effect of resonant impurity scattering of carriers on Drude peak b roadening in uniaxially strained graphene DTSTART;VALUE=DATE-TIME:20191223T103500Z DTEND;VALUE=DATE-TIME:20191223T105500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-120@indico.bitp.kiev.ua DESCRIPTION:Speakers: V. O. Shubnyi (Bogolyubov Institute for Theoretical Physics Institute for Condensed Matter of the National Academy of Sciences of Ukraine\, Kyiv)\nAn explanation is proposed for the recently observed in optical spectra of monolayer graphene giant increase in the Drude-peak width under applied uniaxial strain. We argue that the underlying mechanis m of this increase can be based on resonant scattering of carriers from in evitably present impurities such as adsorbed atoms that can be described b y the Fano-Anderson model. We demonstrate that the often neglected scalar deformation potential plays the essential role in this process. The condit ions necessary for the maximum effect of the giant Drude-peak broadening a re determined. It is stressed that the effect is strongly enhanced when th e Fermi level gets closer to the Dirac point. Our theoretical analysis pro vides guidelines for functionalizing graphene samples in a way that would allow to modulate efficiently the Drude-peak width by the applied strain.\ n\nhttps://indico.bitp.kiev.ua/event/4/contributions/120/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/120/ END:VEVENT BEGIN:VEVENT SUMMARY:Epigenetics: "read" between DNA lines DTSTART;VALUE=DATE-TIME:20191223T120000Z DTEND;VALUE=DATE-TIME:20191223T124500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-161@indico.bitp.kiev.ua DESCRIPTION:Speakers: A.V. Shestopalova (A.Ya. Usikov Institute for Radiop hysics and Electronics National Academy of Sciences of Ukraine\, Kharkiv)\ nhttps://indico.bitp.kiev.ua/event/4/contributions/161/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/161/ END:VEVENT BEGIN:VEVENT SUMMARY:Bose gas with repulsive interactions between particles DTSTART;VALUE=DATE-TIME:20191224T151500Z DTEND;VALUE=DATE-TIME:20191224T153500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-145@indico.bitp.kiev.ua DESCRIPTION:Speakers: Yehor Bondar (Taras Shevchenko National University o f Kyiv)\nBose-Einstein condensation (BEC) and particle number fluctuations are considered in the gas of bosons with repulsive interactions between p articles. Two different mean-field models of the interacting Bose gas are studied. They provide rather different predictions for the BEC transition temperatures and the scaled variances of particle number fluctuations. The behavior of the BE condensate in the different versions of the mean-field approach is also investigated.\n\nhttps://indico.bitp.kiev.ua/event/4/con tributions/145/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/145/ END:VEVENT BEGIN:VEVENT SUMMARY:Backward nucleon production by heavy baryonic resonances in proton -nucleus collisions DTSTART;VALUE=DATE-TIME:20191224T153500Z DTEND;VALUE=DATE-TIME:20191224T155500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-136@indico.bitp.kiev.ua DESCRIPTION:Speakers: Oleksandra Panova (Taras Shevchenko National Univers ity of Kyiv)\nThe production of backward nucleons\, $N(180^\\circ)$\, at $180^\\circ $ in the nuclear target rest frame in proton-nucleus (p~+~$A$) collisions is studied. The backward nucleons appearing outside of the kin ematically allowed range of proton-nucleon (p~+~$N$) reactions are shown t o be due to secondary reactions of heavy baryonic resonances produced insi de the nucleus. Baryonic resonances $R$ created in primary p~+~$N$ reactio ns can change their masses and momenta due to successive collisions $R+N\\ rightarrow R +N $ with other nuclear nucleons. Two distinct mechanisms an d kinematic restrictions are studied: the reaction $R+N\\rightarrow N(180^ \\circ)+N$ and the resonance decay $R\\rightarrow N(180^\\circ) +\\pi$. Si mulations of p~+~$A$ collisions using the Ultra-relativistic Quantum Molec ular Dynamics model support these mechanisms and are consistent with avai lable data on proton backward production.\n\nhttps://indico.bitp.kiev.ua/e vent/4/contributions/136/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/136/ END:VEVENT BEGIN:VEVENT SUMMARY:Chern-Simons portal DTSTART;VALUE=DATE-TIME:20191224T155500Z DTEND;VALUE=DATE-TIME:20191224T161500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-133@indico.bitp.kiev.ua DESCRIPTION:Speakers: Pavlo Kashko (Taras Shevchenko National University o f Kyiv\, Faculty of Physics)\nThe Standard Model (SM) is the best theory o f particle physics for today\, giving precise predictions. However\, it fa ils to explain some fundamental problems such as the strong CP problem\, n eutrino oscillations\, matter-antimatter asymmetry\, and the nature of dar k matter and dark energy.\nTo resolve these problems it seems reasonable t o add new particles to the SM. Since these particles are not detected the y can be either very heavy (with a mass more than energy scale of the avai lable accelerators) or light but very weakly interacting with the SM parti cles. The particles of the last type\, also called feebly interacting mass ive particles (FIMPs)\, can be searched in intensity frontier experiments like SHiP.\nOne can classify FIMPs by their type: scalar\, pseudoscalar\, fermion\, vector or pseudovector particles and interaction with SM. The mo st promising to search are such interactions that connect FIMP to the SM i n a renormalizable way or using low-order operators. If these particles ar e light their parameters and interaction with the SM particles can be dete rmined by physics at a very large scale.\nIn this talk\, we considered the Chern-Simons extension of the SM by the new light pseudovector particle b ecause this extension of the SM was relatively recently proposed and it is not sufficiently studied. \nWe have analytically calculated the process of heavy quark decay into light quark and pseudovector boson that allows u s to calculate the process of heavy meson decay with Chern-Simons particle production. These results will be used to find the sensitivity of the SHi P experiment to detect Chern-Simons particles.\n\nhttps://indico.bitp.kiev .ua/event/4/contributions/133/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/133/ END:VEVENT BEGIN:VEVENT SUMMARY:Modelling of Spectral Energy Distribution from Protoplanetary Disk of IRAS 22150+6109 DTSTART;VALUE=DATE-TIME:20191223T161500Z DTEND;VALUE=DATE-TIME:20191223T162000Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-135@indico.bitp.kiev.ua DESCRIPTION:Speakers: Illia Bilinskyi (Taras Shevchenko National Universit y of Kyiv\, Akademika Hlushkova Ave\, 4\, Kyiv\, Ukraine\, 03022)\nWe pres ent the result of modelling of spectral energy distribution of the infrare d source IRAS 22150+6109. The object emits an excess of radiation in far i nfrared band. It was interpreted to be a young massive pre-main-sequence s tar and the protoplanetary disk on late stage. We use radiative transfer code RADMC-3D for the simulations of spectral energy distribution. The cod e itself implements the Monte-Carlo ray tracing method with spherical grid fragmentation. We performed simulations and obtained best-fit parameters for the model of the protoplanetary disk. The investigation of such objec ts will help to understand protoplanetary disks emission better.\n\nhttps: //indico.bitp.kiev.ua/event/4/contributions/135/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/135/ END:VEVENT BEGIN:VEVENT SUMMARY:The influence of the three-particle interaction on critical phenom ena of the Bose-Hubbard Model DTSTART;VALUE=DATE-TIME:20191223T142500Z DTEND;VALUE=DATE-TIME:20191223T144500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-141@indico.bitp.kiev.ua DESCRIPTION:Speakers: Oleksii Kryvchikov (B.Verkin Institute for Low Tempe rature Physics and Engineering of the National Academy of Sciences of Ukra ine)\nThe critical behavior of a mixture of two types of ultracold bosons on the optical lattice was studied. The system can be described by the Bos e-Hubbard model. It is known that the system can be in a superfluid or in a Mott insulator state\, depending on the hopping parameter and chemical p otential. The interaction between different types of particles drastically changes the phase diagram. In particular\, the transitions between mixed and superfluid states appear. The presence of a three-particle interaction leads to an increase in the Mott insulator region of the phase diagram. I n particular\, bosons with a higher hopping value can be still in the Mott insulator phase. The results are obtained in the framework of the mean-fi eld approximation for a wide range of parameters.\n\nhttps://indico.bitp.k iev.ua/event/4/contributions/141/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/141/ END:VEVENT BEGIN:VEVENT SUMMARY:Nuclear critical point and fluctuations of conserved charges DTSTART;VALUE=DATE-TIME:20191224T135500Z DTEND;VALUE=DATE-TIME:20191224T141500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-139@indico.bitp.kiev.ua DESCRIPTION:Speakers: Roman Poberezhnyuk (Bogolyubov Institute for Theoret ical Physics of the National Academy of Sciences of Ukraine\, Kyiv)\nThe c hemical freeze-out parameters in central nucleus-nucleus collisions are ex tracted consistently from hadron yield data within the quantum van der Waa ls (QvdW) hadron resonance gas model. The beam energy dependences for skew ness and kurtosis of net baryon\, net electric\, and net strangeness char ges are predicted. The QvdW interactions in asymmetric matter\, $Q/B \\neq 0.5$\, between (anti)baryons yield a non-congruent liquid-gas phase trans ition\, together with a nuclear critical point (CP) with critical temperat ure of $T_c=19.5$ MeV. The nuclear CP yields the collision energy dependen ce of the skewness and the kurtosis to both deviate significantly from the ideal hadron resonance gas baseline predictions even far away\, in $(T\,\ \mu_B)$-plane\, from the CP. These predictions can readily be tested by S TAR and NA61/SHINE Collaborations at the RHIC BNL and the SPS CERN\, respe ctively\, and by HADES at GSI. The results presented here offer a broad op portunity for the search for signals of phase transition in dense hadronic matter at the future NICA and FAIR high intensity facilities.\n\nhttps:// indico.bitp.kiev.ua/event/4/contributions/139/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/139/ END:VEVENT BEGIN:VEVENT SUMMARY:First passage time distribution for spiking neuron with fast inhib itory feedback stimulated with renewal stream DTSTART;VALUE=DATE-TIME:20191223T150500Z DTEND;VALUE=DATE-TIME:20191223T152500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-140@indico.bitp.kiev.ua DESCRIPTION:Speakers: Olha Shchur (Bogolyubov Institute for Theoretical Ph ysics of the National Academy of Sciences of Ukraine\, Kyiv)\nWe consider a class of spiking neuron models defined by a set of conditions typical f or basic threshold-type models\, such as leaky integrate-and-fire model an d some artificial neurons. A series of impulses\, representing a point re newal process\, is applied to a neuron. Each output impulse is fed back to the neuron after a fixed time delay\, $\\Delta$. This impulse acts as an impulse received through a fast inhibitory (GABA$_a$) synapse.\n$~~~~~~~~ $In our previous work [1]\, we have obtained a general relation in case of input Poisson stream for calculating exactly the probability density func tion (PDF) $p(t)$ for the distribution of the first passage time of crossi ng the threshold.\n$~~~~~~~~$In the present work\, we have obtained a simi lar results but applicable in case of any renewal input stream. The calcul ation is based on the known PDF $p^0(t)$ for the same neuron without feedb ack and the PDF of interspike intervals for input stream\, $p^{in}(t)$.\n \n[1]. Vidybida\, A.\, Shchur\, O. Relation between firing statistics of s piking neuron with delayed fast inhibitory feedback and without feedback\, *Fluctuation and Noise Letters*\, 17(01):1850005 (2018).\n\nhttps://indic o.bitp.kiev.ua/event/4/contributions/140/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/140/ END:VEVENT BEGIN:VEVENT SUMMARY:Compessibility excess and structurization of binary granular mixtu re DTSTART;VALUE=DATE-TIME:20191223T153000Z DTEND;VALUE=DATE-TIME:20191223T153500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-146@indico.bitp.kiev.ua DESCRIPTION:Speakers: Liudmyla Sidletska (Odesa State Environmental Univer sity)\nWe consider the property of compressibility of the binary granular mixture paying attention to their local structurization. The Kirkwood-Buff theory [1] has been used in order to provide theoretical description of t he free volume and compessibility of model bi-component system [2]. Releva nt characters of compactivity has been expressed in terms of partial prope rties of species. For theoretical modelling of respective reference data w e use either hard sphere model or phenomenological data extracted from the physical measurement [3\,4].\nWe show the existence of the nonmonotonic c haracter of the velocity of compaction (different time-scale kinetics) and polodispersive content of system which pass the compression.\n\n[1]. Kirk wood J.G.\, Buff F.P. The statistical mechanical theory of solutions. I. J. Chem. Phys. 19\, 774 (1951)\; https://doi.org/10.1063/1.1748352\n[2]. G erasymov O.I.\, Somov M.M. Statistical description of excess properties of many-particle binary systems. Ukr. J. Phys. 60\, 324 (2015)\; https://doi .org/10.15407/ujpe60.04.0324\n[3]. Aliotta F.\, et al. Excess compressibil ity in binary liquid mixtures. J. Phys. Chem. 126\, 224508 (2007)\; https: //doi.org/10.1063/1.2745292\n[4]. Pilliteri S.\, Lumay G.\, Opsomer E.\,Va ndewalle N. From jamming to fast compaction dynamics in granular binary m ixtures. Sci. Rep. 9\, 7281 (2019)\; https://doi.org/10.1038/s41598-019-43 519-6\n\nhttps://indico.bitp.kiev.ua/event/4/contributions/146/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/146/ END:VEVENT BEGIN:VEVENT SUMMARY:Competitive interaction of hydrogen peroxide and water molecules w ith DNA recognition sites DTSTART;VALUE=DATE-TIME:20191223T124500Z DTEND;VALUE=DATE-TIME:20191223T130500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-142@indico.bitp.kiev.ua DESCRIPTION:Speakers: Oleksii Zdorevskyi (Bogolyubov Institute for Theoret ical Physics of the National Academy of Sciences of Ukraine\, Kyiv)\nIon b eam therapy is one of the most progressive methods in cancer treatment. St udies of water radiolysis process show that under the action of ionizing i rradiation in the medium of biological cell different atomic and molecular species occur. The most long-living among them are hydrogen peroxide (H$_ 2$O$_2$) molecules. But the role of hydrogen peroxide molecules in the dea ctivation of the DNA of cancer cells in ion beam therapy has not been dete rmined yet. \n$~~~~~~~~$In the present work competitive interaction of hyd rogen peroxide and water molecules with atomic groups of non-specific (pho sphate groups) and specific (nucleic bases) DNA recognition sites is inves tigated. Interaction energies and optimized spatial configurations of the considered molecular complexes are calculated with the help of atom-atom p otential functions method and density functional theory. It is shown that hydrogen peroxide molecule can form a complex with PO$_4$ group (with and without sodium counterion) that is more energetically stable than the same complex with water molecule. Also the atomic groups of Adenine\, Thymine\ , Guanine and Cytosine that are more energetically favorable to be bound b y H$_2$O$_2$ rather than by H$_2$O molecule are determined. Moreover\, spa tial configurations of AT and GC base pairs stabilized much better by hydr ogen peroxide rather than by water molecule are found. These configuration s can occur on the pathways of opening of DNA base pairs during DNA unzipp ing experiments. Consequently\, formation of such complexes can block gene tic information transfer processes in cancer cells and can be a key factor during ion beam therapy treatment.\n\nhttps://indico.bitp.kiev.ua/event/4 /contributions/142/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/142/ END:VEVENT BEGIN:VEVENT SUMMARY:Ferroelectric nanocomposites: influence of nanoparticle sizes dist ribution on pyroelectric and electrocaloric conversion parameters DTSTART;VALUE=DATE-TIME:20191223T154500Z DTEND;VALUE=DATE-TIME:20191223T155000Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-138@indico.bitp.kiev.ua DESCRIPTION:Speakers: Hanna Shevliakova (Department of Microelectronics\, National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”\, Kyiv\, Ukraine)\nPyroelectric (PE) and electrocaloric (EC) properties on the ferroelectric-antiferroelectric phase boundary of ferro electric (FE) thin films\, multilayers and other low-dimensional materials can significantly differ from PE and EC properties of bulk single crystal s\, solid solutions and ceramics. In fact\, even for FE nanoparticles\, fo r which efficient synthesis procedures and methods for controlling polar p roperties have already been developed\, there are still many technological problems [1] and the mysteries of theory [2]. In particular\, under consi deration of EC effect in BaTiO3 nanoparticle within the core–shell model [3]\, the depolarization effects\, which are inevitable in the case of ze ro polarization\, were completely neglected. This fact does not allows to apply the obtained in Ref. [1] results to real systems. Using phenomenolog ical Landau-Ginsburg-Devonshire theory and the approximation of the effect ive medium\, typical dependences of the parameters PE and EC conversion on the external electric field\, temperature\, and radius for spherical mono domain FE nanoparticles with fixed radius were calculated analytically in Ref. [4]. In this work typical dependences of the parameters PE and EC con version for nanocomposites with spherical monodomain FE nanoparticles of d ifferent sizes have been calculated analytically.\n\n[1]. U. Idehenre\, Y. A. Barnakov\, S. A. Basun\, D. R. Evans\, Spectroscopic studies of the ef fects of mechanochemical synthesis on BaTiO3 nanocolloids prepared using h igh-energy ball-milling\, J. Appl. Phys.\, 124\, pp. 165501-1-5\, (2018).\ n[2]. Y. A. Barnakov\, I. U. Idehenre\, S. A. Basun\, T. A. Tyson\, D. R. Evans\, Uncovering the mystery of ferroelectricity in zero dimensional nan oparticles\, Nanoscale Advances\, 1\, pp. 664-670\, (2019).\n[3]. C. Xiqu and C. Fang\, Study of electrocaloric effect in barium titanate nanopartic le with core–shell model\, Physica B: Cond. Matt.\, 415\, pp. 14-17 (201 3).\n[4]. A. N. Morozovska\, E. A. Eliseev\, M. D. Glinchuk\, H. V. Shevli akova\, G. S. Svechnikov\, M. V. Silibin\, A. V. Sysa\, A. D. Yaremkevich\ , N. V. Morozovsky\, and V. V. Shvartsman\,. Analytical description of the size effect on pyroelectric and electrocaloric properties of ferroelectri c nanoparticles\, Phys. Rev. Materials\, Vol. 3\, Iss. 10\, 104414\, (2019 ).\n\nhttps://indico.bitp.kiev.ua/event/4/contributions/138/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/138/ END:VEVENT BEGIN:VEVENT SUMMARY:Searching the warm dark matter signatures from Cosmic Dawn and Rei onization epoch DTSTART;VALUE=DATE-TIME:20191224T083500Z DTEND;VALUE=DATE-TIME:20191224T085500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-144@indico.bitp.kiev.ua DESCRIPTION:Speakers: Anton Rudakovskyi (Bogolyubov Institute for Theoreti cal Physics of the National Academy of Sciences of Ukraine\, Kyiv)\nThe or igin of dark matter (DM) is one of the most intriguing questions in modern physics.\nOne of the most promising DM models is the so-called `warm' dar k matter (WDM) with particle mass in the range of keVs.\nThe signature of warm dark matter could be fewer small size dark matter halos and small mas s galaxies in the early Universe (compared to the standard "cold dark matt er" (CDM) scenario).\nThe Cosmic Dawn and Reionization epoch are an imprin t of structure formation in the Universe\, which depends both on the DM na ture and baryonic processes. Therefore the study of this era may shed lig ht on the properties of the dark matter particles as well as on the of bar yonic processes during the formation of earliest structures in the Univers e.\nWe analyze the different observational datasets about the Cosmic Dawn epoch and find that the thermal relic warm dark matter with particle mass $≳$ 2 keV is in an agreement with these observations.\n\nhttps://indico. bitp.kiev.ua/event/4/contributions/144/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/144/ END:VEVENT BEGIN:VEVENT SUMMARY:X-ray photoemission spectra for the Falicov-Kimball model with cor related hopping DTSTART;VALUE=DATE-TIME:20191223T093500Z DTEND;VALUE=DATE-TIME:20191223T095500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-149@indico.bitp.kiev.ua DESCRIPTION:Speakers: Danylo Dobushovskyi (Institute for Condensed Matter of the National Academy of Sciences of Ukraine\, Lviv)\nWe present the res ults of the investigation of X-ray photoemission spectra (XPS) for the str ongly correlated electron system with both local and nonlocal correlations (correlated hopping). We consider the Falicov–Kimball model\, the simpl est model of strongly correlated electrons\, extended by the inclusion of the interaction with deep core-hole state. Despite its simplicity\, the Fa licov–Kimball model has a metal-insulator transition for large Coulomb r epulsion and is exactly solvable via dynamical mean-field theory in infini te dimensions. XPS response at finite temperatures is connected with the c ore-hole propagator\, which is exactly expressed by the functional determi nants on the Keldysh contour in time domain. \n$~~~~~~$Present study is a continuation of our previous works\, which considered the effect of correl ated hopping on thermal transport and optical spectra. As we found previou sly for a wide range of the correlated hopping parameters\, there are some singularities on the single-particle density of states and on the transpo rt function (“quasiparticle” scattering time). Due to these anomalies and violation of the electron-hole symmetry\, there is a huge enhancement of the thermoelectric properties and optical conductivity exhibits a numbe r of interesting features in the vicinity of these singularities. We show to what extent these anomalous features can be manifested on the X-ray pho toemission spectra at finite temperatures.\n\nhttps://indico.bitp.kiev.ua/ event/4/contributions/149/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/149/ END:VEVENT BEGIN:VEVENT SUMMARY:Low-frequency vibrations of water molecules in the hydration spine of DNA minor groove DTSTART;VALUE=DATE-TIME:20191223T130500Z DTEND;VALUE=DATE-TIME:20191223T132500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-151@indico.bitp.kiev.ua DESCRIPTION:Speakers: Tatyana Bubon (Bogolyubov Institute for Theoretical Physics of the National Academy of Sciences of Ukraine\, Kyiv)\nUnder the natural conditions\, DNA macromolecule takes the form of a double helix w hich structure is stabilized by water molecules and metal ions. The organi zation of the ion-hydration environment of the macromolecule depends on a region of the double helix. In particular\, in the minor groove of the mac romolecule the water molecules are highly structured and the spine of wate r molecules\, bridging the N$_3$ atoms of purine and O$_2$ atoms of pyrimi dine bases\, is formed. The dynamics of water molecules in the DNA water s pine should be characterized by the vibrations in the same spectra range a s the conformational vibrations of DNA. Therefore\, the goal of our study was the determination of distinctive vibration modes of water molecules in the DNA minor groove that may be observed in the low-frequency spectra. O n the basis of the approach for the description of DNA conformational dyna mics [2]\, the vibrational model has been elaborated. In the model the nuc leosides are considered as physical pendulums\, rotating around phosphate groups in the plane perpendicular to the helical axis\, and water molecule s are presented as the masses attached to physical pendulums in different pairs. The parameters of the model [2] and the results of molecular dynami cs simulations [3] were used for the estimation of the frequencies and amp litudes of vibrations. As a result the mode of water translational vibrati ons in the hydrated spine of DNA minor groove has been established. This m ode characterizes the displacements of water molecule as a single whole fr om the equilibrium position in the frequency range within 170 – 270 cm$^ {-1}$. The comparison of the obtained results with the experimental spectr a of DNA in an aqueous environment showed that in this region of the vibra tional spectra the translational vibrations of water molecules in the bulk phase as well as ion-phosphate vibrations of DNA are observed. Thus\, the obtained results ground the presence of the mode of vibrations of water m olecules in the hydration spine of the DNA minor groove among the modes of DNA conformational vibrations. \n\n[1] Drew H.R.\, Dickerson R.E.\, J. Mo l. Biol.\, **151**\, 535−556 (1981)\n[2] Volkov S.N.\, Kosevich A.M.\, J . Biomol. Struct. Dyn. **8**\, 1069 (1990)\n[3] Perepelytsya S.M.\, Journa l of Molecular Modeling\, **24**\, 171 (2018).\n\nhttps://indico.bitp.kiev .ua/event/4/contributions/151/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/151/ END:VEVENT BEGIN:VEVENT SUMMARY:Influence of the cell wall on cyanide destruction by bacteria in t he model of respiratory mechanism DTSTART;VALUE=DATE-TIME:20191223T132500Z DTEND;VALUE=DATE-TIME:20191223T134500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-150@indico.bitp.kiev.ua DESCRIPTION:Speakers: Vladyslav Yakovliev (Bogolyubov Institute for Theore tical Physics of the National Academy of Sciences of Ukraine\, Kyiv)\nThe research is based on the ideology that the destructive centers of cyanides in living microorganisms are respiratory centers\, the destruction of cya nides is investigated. The phenomenological equations are used in the work . These equations are not linear and approximate analytical solutions are found for them. The kinetics of destruction of previously experimentally d etected dependencies on the preliminary treatment of a suspension with mic roorganisms by a pulsed electric field is described. The calculations were carried out taking into account the limited transparency of the bacterial cell wall. It is demonstrated that low permeability of the cell wall cont ributes to the survival of microorganisms in the aggressive environment. T he dependence of the transparency of the cell wall on the influence of a p ulsed electric field was found. In particular\, the exponential dependence of transparency on the field amplitude is demonstrated. The calculation r esults are consistent with the experiment at a fixed value of the paramete rs. The agreement between theory and experiment in the entire range of vol tage values for the amplitude of the electric field is available.\n\nhttps ://indico.bitp.kiev.ua/event/4/contributions/150/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/150/ END:VEVENT BEGIN:VEVENT SUMMARY:The covalent radii derived from the first-principle data DTSTART;VALUE=DATE-TIME:20191223T162000Z DTEND;VALUE=DATE-TIME:20191223T162500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-152@indico.bitp.kiev.ua DESCRIPTION:Speakers: Valerii Chuiko (Faculty of Physics of Taras Shevchen ko National University of Kyiv)\nThe concept of atomic covalent radius for ms the basis for one of the simplest parameterizations for prediction of t he covalent bond length and recovering molecular graphs from the set of in teratomic distances. In the present contribution we adopt the recently pro posed dataset [1] of covalent bond lengths resulting from the first-princi ple calculations to derive the covalent radii for H\, B\, C\, N\, O\, F\, Si\, P\, S\, Cl\, Ge\, As\, Se and Br elements within the additive covalen t bond length model. The obtained first-principle covalent radii are shown to be in good agreements ones based on empirical data [2]. Availability o f the large-size dataset of covalent bond lengths enabled the further anal ysis of errors in approximating the covalent bond length with the sum of t he covalent radii. In particular\, the effects of electronic conjugation a nd the chemical elements electronegativity difference were investigated [3 ].\n\n[1] Nikolaienko\, T. Y.\, Chuiko\, V. S.\, & Bulavin\, L. A. (2019). The dataset of covalent bond lengths resulting from the first-principle c alculations. Computational and Theoretical Chemistry\, 112508.\n[2] Pyykk ö\, P. (2015). Additive covalent radii for single-\, double-\, and triple -bonded molecules and tetrahedrally bonded crystals: a summary. The Journa l of Physical Chemistry A\, 119(11)\, 2326-2337.\n[3] Nikolaienko\, T. Y.\ , Chuiko\, V. S.\, & Bulavin\, L. A. (2019). The covalent radii derived fr om the first-principle data. arXiv preprint arXiv:1906.11724\n\nhttps://in dico.bitp.kiev.ua/event/4/contributions/152/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/152/ END:VEVENT BEGIN:VEVENT SUMMARY:Polarization effects of algebraically special Maxwell field in the Kerr space-time DTSTART;VALUE=DATE-TIME:20191224T103500Z DTEND;VALUE=DATE-TIME:20191224T105500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-132@indico.bitp.kiev.ua DESCRIPTION:Speakers: Yurii Taistra (Pidstryhach Institute for Applied Pro blems of Mechanics and Mathematics National Academy of Sciences of Ukraine \, Lviv)\nFor obtaining polarization effects in the Kerr space-time we hav e used algebraically special approach for Maxwell equations [1].\nAs a con sequence\, in Kinnersley tetrad Maxwell field is described only by one ext remal component $\\varphi_2$\, and the Maxwell equations have closed-form solution [2]:\n\n$\\varphi_2= C \\frac{e^{i\\omega (t-\\tilde{r}) + i m \\ phi }}{\\sin\\theta(r- i a \\cos\\theta)} e^{-a\\omega\\cos\\theta} \\left (\\frac{1-\\cos\\theta}{\\sin\\theta}\\right)^m$\,\n\nwhere $t>0$\, $ r_+ \n\nhttps://indico.bitp.kiev.ua/event/4/contributions/132/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/132/ END:VEVENT BEGIN:VEVENT SUMMARY:Thermal counterflow and electrical activity of superfluid systems in a magnetic field DTSTART;VALUE=DATE-TIME:20191223T081500Z DTEND;VALUE=DATE-TIME:20191223T083500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-115@indico.bitp.kiev.ua DESCRIPTION:Speakers: Aleksandr Konstantinov (B.Verkin Institute for Low T emperature Physics and Engineering of the National Academy of Sciences of Ukraine)\nIt is shown that the thermal counterflow in superfluid helium p laced in a magnetic field leads to the appearance of an electric field in the surrounding space. The effect is due to the counterflow nature of ther mal conductivity in superfluid systems: heat transfer in such systems is a ssociated with the movement of the normal component\, but the average mass flow carried by the normal component is compensated by the mass flow carr ied by the superfluid component. The local mass flow is nonzero. The effec t occurs for stationary and non-stationary (second sound) heat flow. The f eatures of the effect for samples with different geometries are considered . It was established that the magnitude of the arising electric field subs tantially depends on the shape of the sample and the direction of the magn etic field [1].\n\n[1] S.I. Shevchenko\, A.M. Konstantinov\, JETP Lett. 10 9\, 790-794\, (2019).\n\nhttps://indico.bitp.kiev.ua/event/4/contributions /115/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/115/ END:VEVENT BEGIN:VEVENT SUMMARY:Binding of antibiotic drug molecules to the surface of silver nano particles: tight-binding DFT study DTSTART;VALUE=DATE-TIME:20191223T162500Z DTEND;VALUE=DATE-TIME:20191223T163000Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-153@indico.bitp.kiev.ua DESCRIPTION:Speakers: Olha Husak (Faculty of Physics of Taras Shevchenko N ational University of Kyiv)\nEnhancement of therapeutic activity of organi c drug molecules bound to nanoparticle surface has recently been highlight ed as a possible way to overcome resistance of bacteria towards traditiona l antibiotics [1]. Investigation of the physical interactions responsible for such complexation\, however\, becomes challenging when nanoparticle is formed by transition metal atoms due to the need of accurate treatment of the nanoparticle polarizability [2]. Purely ab initio approaches\, on the other hand\, are typically ruled out by the number of atoms in such syste ms and consequent demands for computational resources. In the variety of m olecular modeling approaches available nowadays\, the density-functional b ased tight-binding (DFTB) method is unique in combining the clear hierarch y of physically sound approximations with high computational efficiency [3 ]\, thus\, being ideal for treating the systems of hundreds of atoms in re asonable time.\nIn the present contribution we report the applications of DFTB-based automated conformational searching algorithms [4] to obtain the energetically most stable complexes formed by organic drug molecules Ceft riaxone and Doxorubicin with silver nanoparticles (ca. 1 nm diameter) of d ifferent shapes. \n\n[1] A. Panáček\, M et al.\, Molecules (2016)\, Vol. 21\, P. 26.\n[2] F. Iori\, S. Corni. J. Comput. Chem.(2008)\, 29(10)\, 1 656-1666.\n[3] J. Cuny\, N. Tarrat\, F. Spiegelman\, A. Huguenot\, M. Rap acioli. J. Phys. Condens. Matter (2018)\, Vol. 30\, p. 303001.\n[4] S. Gri mme. ‎J. Chem. Theory Comput (2019)\, 15(5)\, 2847-2862.\n\nhttps://indi co.bitp.kiev.ua/event/4/contributions/153/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/153/ END:VEVENT BEGIN:VEVENT SUMMARY:Thermodynamic properties of an interacting boson system DTSTART;VALUE=DATE-TIME:20191224T143500Z DTEND;VALUE=DATE-TIME:20191224T145500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-157@indico.bitp.kiev.ua DESCRIPTION:Speakers: D. Zhuravel (Bogolyubov Institute for Theoretical Ph ysics of the National Academy of Sciences of Ukraine\, Kyiv)\nWe consider the thermodynamical properties of an interacting boson system at finite te mperatures and zero chemical potential within the framework of the Skyrme- like mean-field model. Self-consistency relations between the mean field a nd thermodynamic functions are derived. For illustration of our approach t he thermodynamic properties of a $\\pi$-meson system are investigated. We numerically solved the self-consistent equation for a particle density and derived all thermodynamical functions as functions of the temperature for different values of an attractive constant of coupling $\\kappa$. It is s hown that for some values of $\\kappa$ this system develops a first-order phase transition via formation of the Bose condensate at non-zero temperat ures. Phase diagrams and the pressure $p/T^4$\, energy density $\\epsilon/ T^4$\, entropy density $s/T^3$\, trace anomaly $(\\epsilon-3p)/T^4$\, spec ific heat $C_V/T^3$\, and the speed of sound $c_s^2$ are calculated in the liquid-gas and condensed phases.\n\nhttps://indico.bitp.kiev.ua/event/4/c ontributions/157/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/157/ END:VEVENT BEGIN:VEVENT SUMMARY:Traces of the nuclear liquid-gas phase transition in the analytic properties of hot QCD DTSTART;VALUE=DATE-TIME:20191224T145500Z DTEND;VALUE=DATE-TIME:20191224T151500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-131@indico.bitp.kiev.ua DESCRIPTION:Speakers: Oleh Savchuk (Taras Shevchenko National University o f Kyiv)\nThe nuclear liquid-gas transition at normal nuclear densities\, n ∼n0=0.16 fm−3\, and small temperatures\, T∼20 MeV\, has a large infl uence on analytic properties of the QCD grand-canonical thermodynamic pote ntial. A classical van der Waals equation is used to determine these unexp ected features due to dense cold matter qualitatively. The existence of th e nuclear matter critical point results in thermodynamic branch points\, w hich are located at complex chemical potential values\, for $T>Tc≃20$ Me V\, and exhibit a moderate model dependence up to rather large temperature s $T≲100$ MeV. The behavior at higher temperatures is studied using the van der Waals hadron resonance gas~(vdW-HRG) model. The baryon-baryon inte ractions have a decisive influence on the QCD thermodynamics close to μB= 0. In particular\, nuclear matter singularities limit the radius of conver gence rμB/T of the Taylor expansion in μB/T\, with rμB/T∼2−3 values at T∼140−170 MeV obtained in the vdW-HRG model.\n\nhttps://indico.bit p.kiev.ua/event/4/contributions/131/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/131/ END:VEVENT BEGIN:VEVENT SUMMARY:Determination of the contact angle from transversality conditions of the Lagrange variation problem of wetting DTSTART;VALUE=DATE-TIME:20191223T155500Z DTEND;VALUE=DATE-TIME:20191223T160000Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-156@indico.bitp.kiev.ua DESCRIPTION:Speakers: Oleh Hrebnov (Taras Shevchenko National University o f Kyiv)\nIn recent years\, there has been an increase in studies focused o n the size-dependent contact angle. In the case of the sessile axial symme tric droplet\, the size dependence often is explained by the contribution of the line tension to the Helmholtz free energy as a consequence\, the mo dified Young's equation. There are two major points of view on the contrib ution mechanism. According to the first point of view\, the liner tension is a function of the contact angle\; according to another one\, the line t ension is a function of the three-phase contact line torsion and geodesic curvature. However\, in the case of the straight contact line\, it is impo ssible to determine the influence of the line tension of the three-phase c ontact line on the contact angle. \nWe propose a model of the line tension of the three-phase contact line influence on the contact angle. We consid er the line tension as a thermodynamic work on the deformation transition region on the three-phase border to determine the influence. Therefore\, t he line tension becomes a function of the dividing surface curvature on th e contact line. Then\, the Helmholtz free energy of a unit of the cylindri c nanodroplet length $\\Delta\\textit{x}$ with the additional condition of incompressibility of the nanodroplet liquid is:\n$$\n\\begin{multline}\n\ \ F\\left[z\\left(y\\right)\\right]=\\int\\limits_{x}^{x+\\Delta x}dx \\in t\\limits_{-r}^{r}dyL\\left(y\,z\,z'\,z''\\right)= \\\\\n \\int\\limits_{x }^{x+\\Delta x}dx \\int\\limits_{-r}^{r}dy\\left\\{\\gamma _{sv }-\\gamma _{sl} +\\gamma _{lv } \\left[\\frac{z''^{2} }{\\left(1+z'^{2} \\right)^{3/ 2} } \\right]\\sqrt{1+z'^{2} } +\\frac{1}{r} \\tau \\left[\\frac{z''^{2} } {\\left(1+z'^{2} \\right)^{3/2} } \\right]+\\lambda yz'\\right\\}\,\n\\end {multline}\n$$\nwhere\, $\\textit{2r}$ $-$ the width of the nanodroplet b ase\, $\\gamma$ $-$ the surface tension between liquid/vapor\, solid/liqui d and solid/vapor\, $\\tau$ $-$ the line tension of three-phase contact li ne\, $\\lambda$ $-$ Lagrange multiplier.\nThe transversality conditions of the Lagrange problem with moving boundary for the functional containing t he second-order derivative are:\n$$\n\\begin{equation}\n{\\left[L-z'\\left (\\frac{\\partial L}{\\partial z'}-\\frac{d}{dy} \\frac{\\partial L}{\\par tial z''} \\right)+\\right. \\left. \\left(\\frac{z'\\arctan \\left(z'\\ri ght)\\left(1+z'^{2} \\right)-z'^{2} }{y\\left(\\arctan \\left(z'\\right)-z '\\right)} -z''\\right)\\frac{\\partial L}{\\partial z''} \\right]_{y=-r\, r}=0 }.\n\\end{equation}\n$$\nThe contact angle can be obtained by minimiz ation of the Helmholtz free energy functional with the application of the transversality conditions:\n$$\n\\begin{equation}\n\\left(1-\\left(\\frac{ \\delta _{c} }{R} \\right)+o \\left(\\frac{\\delta _{c} }{R} \\right)^{2} \\right)\\cos \\left(\\theta \\right)=\\frac{\\gamma _{sv } -\\gamma _{sl} }{\\gamma^{\\infty } {}_{lv} } -\\frac{\\tau}{\\gamma^{\\infty } {}_{lv} R\\sin \\left(\\theta \\right)}\,\n\\end{equation}\n$$\nwhere\, $\\delta{} _{c}$ $-$ the Tolman length\, $\\theta$ $-$ the contact angle\, $\\gamma$$ {}^{\\mathrm{\\infty}}{}_{lv}$ $-$ the surface tension of a flat surface\, $R$ $-$ the radius of the liquid-vapor interface curvature.\nIt has been shown that the contact angle depends on the line tension of the straight t hree-phase contact line.\n\nhttps://indico.bitp.kiev.ua/event/4/contributi ons/156/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/156/ END:VEVENT BEGIN:VEVENT SUMMARY:DNN application for hydrodynamic task solution DTSTART;VALUE=DATE-TIME:20191223T163000Z DTEND;VALUE=DATE-TIME:20191223T163500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-155@indico.bitp.kiev.ua DESCRIPTION:Speakers: Kirill Taradiy (Frankfurt Institute for Advanced Stu dies\, Frankfurt am Main\, Germany)\nThe possibility of GPU usage combined with the substitution of numerical computations with the trained neural n etwork for both relativistic and non-relativistic hydrodynamic equations y ields the 104 - 106 performance boost compared to the standard numerical m ethods. The main idea behind the work starts from the fact that neural net work is the so-called perceptron on the universal type. The deep sense beh ind this definition is that actually a neural network with one hidden laye r can become the mapping of any type for smooth differentiable continuous functions. The trained Neural Network can as well perform the role of the time-dependent solution of the hydro-equations performing the regression a nd classification tasks for various types of hydro – solutions. The resu lts of DNN application to the non-relativistic hydro problem are demonstra ted for 1D and 2D cases. Further 3D generalization options and problems ar e discussed.\n\nhttps://indico.bitp.kiev.ua/event/4/contributions/155/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/155/ END:VEVENT BEGIN:VEVENT SUMMARY:Transverse energy transfer by Alfven waves in toroidal plasmas DTSTART;VALUE=DATE-TIME:20191223T140500Z DTEND;VALUE=DATE-TIME:20191223T142500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-159@indico.bitp.kiev.ua DESCRIPTION:Speakers: M.H. Tyshchenko (Institute for Nuclear Research of t he National Academy of Sciences of Ukraine\, Kyiv)\nDestabilized magnetohy drodynamic (MHD) eigenmodes can transfer the energy and momentum from the region where particles (e.g.\, fast ions) drive the plasma instability to another region\, where the destabilized waves are damped. This phenomenon named “spatial channeling” (SC) was predicted in [1\,2]. A key element of the SC is that the energy and momentum of particles driving the instab ility are transferred by the waves (eigenmodes)\, not by the diffusion or heat conduction. In this work the physics of the transverse energy transfe r by Alfven waves in toroidal plasmas is elucidated. It is found that\, in contrast to the classical Alfven waves in infinite plasmas\, the Alfven w aves in toroidal systems produce plasma compression due to coupling with f ast magnetoacoustic waves\, which provides the energy transfer. The radial group velocities of the traveling waves constituting the Global Alfven Ei genmodes and Toroidicity-induced Alfven Eigenmodes are calculated. It is s hown that equation for Alfven eigenmodes derived in the approximation of v anishing wave field along the equilibrium magnetic field reproduce the lon gitudinal magnetic field of the wave and lead to correct transverse energy flux. The obtained results explain how Alfven eigenmodes can provide the spatial energy channeling. The results of this work are published in [3]. \nThis work was supported by the Project No. PL15/18 of the National Acade my of Sciences of Ukraine and the Project No. 6392 of the Science and Tech nology Center in Ukraine (STCU).\n\n[1] Ya. I. Kolesnichenko\, Yu. V. Yako venko\, and V. V. Lutsenko\, Phys. Rev. Lett. **104**\, 075001 (2010)\n[2] Ya. I. Kolesnichenko\, Yu. V. Yakovenko\, V. V. Lutsenko\, R. B. White\, and A. Weller\, et al.\, Nucl. Fusion **50**\, 084011 (2010)\n[3] Ya. I.Ko lesnichenko\, Yu. V. Yakovenko\, and M. H. Tyshchenko\, Phys. Plasmas **25 **\, 122508 (2018)\n\nhttps://indico.bitp.kiev.ua/event/4/contributions/15 9/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/159/ END:VEVENT BEGIN:VEVENT SUMMARY:Analogue Hawking radiation in a ring of Bose-Einstein condensate DTSTART;VALUE=DATE-TIME:20191223T154000Z DTEND;VALUE=DATE-TIME:20191223T154500Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-143@indico.bitp.kiev.ua DESCRIPTION:Speakers: Igor Yatsuta (Department of Physics\, Taras Shevchen ko National University of Kyiv)\nHawking radiation is one of the most fasc inating phenomena taking place near the black hole horizon. Featuring both gravitational and quantum properties this effect is extremely hard to obs erve on the real objects. Surprisingly\, it is possible to mimic evaporati on of particles on the acoustic analogs\, where Bose-Einstein condensate p lays a role of background giving birth for Hawking pairs. This area is sti ll a matter of multiple discoveries providing us with the very first convi ncing observation of Hawking effect analog this year.\n$~~~~~~~~$We addres s a model of effectively one-dimensional (1D) Bose-Einstein condensate (BE C) confined in a toroidal trap. This system is attractive to explore since the total flow of quantum liquid is quantized which results in a restrict ion on possible values of the velocity of the condensate. Moreover\, it is impossible to avoid the presence of the so-called white hole (inner) hori zon in such toroidal geometry.\n$~~~~~~~~$Unlike recent works on the acous tic horizon in toroidal BECs\, we apply the method previously used for mod eling an infinitely long quasi-one-dimensional condensate to our system. I t allows to create acoustic horizons in the condensate with uniform densit y. Remarkably\, we managed to see the correlation pattern having the prope rties of the analog Hawking effect. Obtained correlations turned out to be strongly dependent on the length of the ring and initial noise for the fi xed parameters of the horizon. Furthermore\, for some particular size of the region Hawking correlations disappear that may be an interesting analo gy of the existence of Planck mass limit for real black holes. Also\, we c onsidered the influence of the white hole horizon on the correlation patte rn and stability of the system for different values of surface gravity.\n\ nhttps://indico.bitp.kiev.ua/event/4/contributions/143/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/143/ END:VEVENT BEGIN:VEVENT SUMMARY:Effects of parallel motion on test-particle transport DTSTART;VALUE=DATE-TIME:20191223T163500Z DTEND;VALUE=DATE-TIME:20191223T164000Z DTSTAMP;VALUE=DATE-TIME:20260419T011636Z UID:indico-contribution-4-163@indico.bitp.kiev.ua DESCRIPTION:Speakers: O.M. Cherniak (Bogolyubov Institute for Theoretical Physics of the Natioanal Academy of Sciences of Ukraine\, Kyiv)\nTransport processes play a significant role in the evolution of non-equilibrium pla smas. Various instabilities which exist in such plasma can generate intens e fields that interact with particles and cause the anomalous transport. T he intensity of the generated fields can be high enough to cause anomalous transport exceeding the collisional one. The possible explanation of a si gnificant difference between anomalous and collisional transport character istics is the particle trapping effect.\n The particle trapping effect is the crucial feature for a two-dimensional transport across the magnetic fi eld\, particularly when random electric field has an infinite correlation time. One of the common methods for a theoretical study of this problem is based on the Taylor relation combined with a certain statistical approxim ation of velocity correlation function along the trajectories. In our prev ious work we proposed and validated closure approximation [1] for an infin ite correlation time and expanded it to account for finite Larmor radius e ffects [2] as well as finite correlation time [3]. However\, it is also im portant to study the effect of the particle motion along the magnetic fiel d on the particle transport. \n Here we use numerical simulation to study three-dimensional particle motion in constant magnetic and random electric fields. A set of parameters\, such as random field correlation time\, fin ite Larmor radius and initial longitudinal velocity are considered. The ef fect of these parameters on particle transport are discussed.\n This work is supported by the Project № 20-04/18-2019 of the National Academy of Sciences of Ukraine.\n\n[1] V.I. Zasenko\, A.G. Zagorodny\, O.M. Chernyak\ , Ukr. J. Phys. 56\, 1007 (2011).\n[2] O.M. Cherniak\, V.I. Zasenko\, Ukr. J. Phys. 62\, 495 (2017).\n[3] O.M. Cherniak\, V.I. Zasenko\, J. Phys. Co nf. Ser. 1197\, 012003 (2019).\n\nhttps://indico.bitp.kiev.ua/event/4/cont ributions/163/ LOCATION:Bogolyubov Institute for Theoretical Physics of the National Acad emy of Sciences of Ukraine 322 URL:https://indico.bitp.kiev.ua/event/4/contributions/163/ END:VEVENT END:VCALENDAR