BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Long-range hops in a two-species reaction-diffusion system: renorm alization group and numerical simulations DTSTART;VALUE=DATE-TIME:20211221T095000Z DTEND;VALUE=DATE-TIME:20211221T101000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-226@indico.bitp.kiev.ua DESCRIPTION:Speakers: Dmytro Shapoval (Institute of Condensed Matter Physi cs\, National Academy of Sciences of Ukraine\, 1 Svientsitskii Street\, UA -- 79011 Lviv\, Ukraine \\\\ ${\\mathbb L}^4$ Collaboration \\& Doctoral College for the Statistical Physics of Complex Systems\, Leipzig-Lorraine- Lviv-Coventry)\nWe consider the reaction-diffusion system of two-species w ith an anomalous superdiffusion undergoing the annihilation and coagulatio n reactions $A + A \\to (0\, A)$ as well as the trapping reaction $A + B \ \to A$. The superdiffusion is modeled via long-ranged Lévy flights repres ented by random walks with step-lengths obeying a Lévy distribution $P(r) = r^{- d - \\sigma}$ (a heavy-tailed probability distribution) with contr ol parameter $0\n\nhttps://indico.bitp.kiev.ua/event/8/contributions/226/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/226/ END:VEVENT BEGIN:VEVENT SUMMARY:Pseudopotential method for description of positron annihilation in spherically symmetric potential DTSTART;VALUE=DATE-TIME:20211221T101000Z DTEND;VALUE=DATE-TIME:20211221T103000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-236@indico.bitp.kiev.ua DESCRIPTION:Speakers: Marina Vorona (Institute of Applied Physics NAS of U kraine\, Sumy\, Ukraine)\nThe radiation resistance is the key issue for th e creation of new structural elements for new-generation nuclear reactors and the operation extension of existing nuclear power plants. The study of the mechanisms of formation and dynamics of radiation defects is of consi derable scientific interest. The initial stage of the evolution of radiati on defects is the production of point-type defects. One of the most effect ive methods for studying point defects is spectroscopy of positron lifetim e\, which depends on the electron distribution. Despite the rather simple idea\, its practical implementation is associated with both certain techni cal difficulties\, and the development of a general process theory. The me thod of positron annihilation spectroscopy (PAS) includes measurement of p ositron lifetime\, determination of probabilities of 3γ and 2γ positron annihilation\, influence on the main characteristics of annihilation of va rious external factors [1-3]. The PAS method is used to study the electron structure of the material and the concentrations of point and extended de fects. Local formations (defects) are characterized by reduction of electr on density compared to defect-free regions\, so the lifetime of the positr on is longer in this defect. Each defect is corresponded its own lifetime and the intensity of the corresponding component in the total experimental spectrum\, which determined by the concentration of such defects [1-3]. T he positron annihilation rate is determined by the overlap of the electron and positron densities in the region of the positron localization. It als o depends on the cross section of the electron-positron pair annihilation process.\nA series of methods have been developed to study the electronic structure of matter. They all have their advantages and disadvantages and differ in the required initial data. For this problem\, we considered the pseudopotential method \, which allows us to build the potential of the po sitron-vacancy interaction. The method idea suppose the replacement of the atom potential by a weak potential with the same amplitude of conduction electrons scattering. The method is based on the factorization of the posi tron wave function into an energy-independent basic function and the smoot h envelope (pseudo-wave) function. Thus\, the annihilation process of the positron in a spherically symmetric potential can be described.\n\n[1]. We st\, R. N. Positron Studies of Lattice Defectsin Metals. Positrons in Soli ds\, 1979\, p. 89-144.\n[2]. Puska M.J.\, Nieminen R.M .. Theory of positr onsin solids and on solid surfaces // Reviews of Modern Physics. 1994\, v. 66\, p. 841-897.\n[3]. Grafutin I.\, Prokopyev E.P. Application of positr on annihilation spectroscopy to study the structure of matter\, Physics-Us pekhi (2002)\,45(1):59.\n\nhttps://indico.bitp.kiev.ua/event/8/contributio ns/236/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/236/ END:VEVENT BEGIN:VEVENT SUMMARY:Merging of spinning binary black holes in globular clusters DTSTART;VALUE=DATE-TIME:20211222T084500Z DTEND;VALUE=DATE-TIME:20211222T090500Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-219@indico.bitp.kiev.ua DESCRIPTION:Speakers: Margarita Sobolenko (Main Astronomical Observatory N AS of Ukraine)\nCurrently over 50 gravitational events from compact binari es were reported by LIGO-Virgo consortium. We see Gravitational Waves (GW) as a new and very powerful informational channel. The current GW observat ions contain the Binary Black Hole (BH) systems key orbital parameters\, s uch as mass\, semi-major axis\, eccentricity and even the possible spins o f the BH's. The next 3G generation of ground-based observatories (Einstein Telescope\, Cosmic Explorer) will have the opportunity to work with GWs d uring multiple cycles. It can significantly improve the estimations of ind ividual components parameters of BH's. Based on our current high resolutio n direct N-body modelling of the Milky Way typical Star Cluster systems dy namical evolution we try to numerically estimate the influence of individu al spins values\, orientations and orbital eccentricities on GW waveforms and observed time-frequency maps during multiple cycles for BH binary merg ers. In our\, up to date\, N-body dynamical simulations we use the high or der relativistic post-Newtonian corrections for the BH binary particles (3 .5 post-Newtonian (PN) terms including spin-spin and spin-orbit terms). In the current work we present the GW waveforms catalogue which covers the l arge parameter space in mass ratios 0.05 - 0.82 and extreme possible indiv idual spin cases.\n\nhttps://indico.bitp.kiev.ua/event/8/contributions/219 / LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/219/ END:VEVENT BEGIN:VEVENT SUMMARY:First results of iHKM at RHIC BES energies: measuring shear viscos ity of QGP DTSTART;VALUE=DATE-TIME:20211222T133000Z DTEND;VALUE=DATE-TIME:20211222T135000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-221@indico.bitp.kiev.ua DESCRIPTION:Speakers: Musfer Adzhymambetov (Bogolyubov Institute for Theor etical Physics)\nIntegrated hydro-kinetic model was modified and first tim e applied to baryon-rich matter created in heavy-ion collisions at relativ ely low energies of RHIC BES program. The model employs a transport approa ch at the early and late non-equilibrium stages of evolution of the system and viscous hydrodynamics with smooth continuous thermalization in the mi ddle stage of near-equilibrium expansion of quark-gluon plasma. First res ults for $p_T$ spectra\, elliptic flow\, and femtoscopy are presented. Sim ulations indicate that the most successful description of the existing dat a corresponds to the lowest possible share viscosity to entropy density ra tio $\\eta/s=1/4\\pi$ and fast thermalization with $\\tau_{th}\\sim 0.5$fm /$c$.\n\nhttps://indico.bitp.kiev.ua/event/8/contributions/221/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/221/ END:VEVENT BEGIN:VEVENT SUMMARY:The estimation of pion and kaon maximal emission times in $5.02A$ TeV collisions at the LHC DTSTART;VALUE=DATE-TIME:20211222T131000Z DTEND;VALUE=DATE-TIME:20211222T133000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-238@indico.bitp.kiev.ua DESCRIPTION:Speakers: Volodymyr Shapoval (Bogolyubov Institute for Theoret ical Physics)\nIn [1] a simple method allowing one to estimate the times o f maximal emission for pions and kaons\,created in the LHC Pb+Pb collision s at $\\sqrt{s_{NN}}=2.76$~TeV\, based on the combined fitting of their $p _T$ spectra and the dependences of longitudinal femtoscopy radii on the pa ir transverse mass\, $R_{\\mathrm{long}}(m_T)$\, was proposed and tested w ithin the hydrokinetic model (HKM)\, able to simulate the process of the m atter evolution in course of a relativistic heavy-ion collision. The entir e evolution process is described as passing in several stages within the m odel (the initial state formation\, the hydrodynamical expansion of contin uous medium\, the matter particlization\, and the final "afterburner" hadr on cascade stage). The proposed method was successfully applied to the ana lysis of the experimental data by the ALICE Collaboration~[2].\nIn the cur rent work the same method is applied to the femtoscopy analysis of Pb+Pb c ollisions at a higher LHC energy\, $\\sqrt{s_{NN}}=5.02$~TeV\, within an i mproved model version - the integrated hydrokinetic model (iHKM)\, which\, in particular\, additionally includes the simulation of the pre-thermal s tage of the system's evolution and viscous (instead of previously used ide al) hydrodynamics for the description of (quasi)equilibrated expansion of nearly thermalized quark-gluon matter. \nThe obtained fitting results for pion and kaon maximal emission times in the three centrality classes are c onsistent with the corresponding approximate time values\, estimated based on the model emission function graphs~[3]. Thus\, the method can be propo sed for use in the experimental analysis of A+A collisions at the current LHC energy. The extracted maximal emission time values decrease\, when one goes from central to non-central events. The kaons are emitted later than pions\, mainly due to the $K^*(892)$ resonance decay contribution to the total kaon yield. The $m_T$ scaling between pions and kaons gets broken be cause of the strong transverse collective flow at the hydrodynamical stage and the intensive hadron-hadron scatterings at the post-hydrodynamical st age of the collision.\n\n[1] Yu.M. Sinyukov\, V.M. Shapoval\, V.Yu. Naboka \, Nucl. Phys. A $\\textbf{946}$\, 227 (2016).\n[2] J. Adam $\\textit{et a l.}$ (ALICE Collaboration)\, Phys. Rev. C $\\textbf{96}$\, 064613 (2017).\ n[3] V.M. Shapoval\, Yu.M. Sinyukov\, Nucl. Phys. A $\\textbf{1016}$\, 122 322 (2021).\n\nhttps://indico.bitp.kiev.ua/event/8/contributions/238/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/238/ END:VEVENT BEGIN:VEVENT SUMMARY:Critical point and Bose-Einstein condensation in pion matter DTSTART;VALUE=DATE-TIME:20211222T125000Z DTEND;VALUE=DATE-TIME:20211222T131000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-231@indico.bitp.kiev.ua DESCRIPTION:Speakers: Vladimir Kuznietsov (Taras Shevchenko National Unive rsity of Kyiv)\nThe Bose-Einstein condensation and the liquid-gas first-or der phase transition are studied in the interacting pion matter. Two pheno menological models are used: the mean-field model and the hybrid model. Fr ee model parameters are fixed by fitting the lattice QCD data on the pion Bose condensate density at zero temperature. In spite of some minor differ ences\, the two models demonstrate an identical qualitative and very close quantitative behavior for the thermodynamic functions and electric charge fluctuations. A peculiar property of the considered models is an intersec tion of the Bose-Einstein condensation line and the line of the first-orde r phase transition at the critical endpoint.\n\nhttps://indico.bitp.kiev.u a/event/8/contributions/231/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/231/ END:VEVENT BEGIN:VEVENT SUMMARY:Constraining baryon annihilation in the hadronic phase of heavy-io n collisions via event-by-event fluctuations DTSTART;VALUE=DATE-TIME:20211222T123000Z DTEND;VALUE=DATE-TIME:20211222T125000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-230@indico.bitp.kiev.ua DESCRIPTION:Speakers: Oleh Savchuk (Bogolyubov Institute for Theoretical P hysics of the National Academy of Sciences of Ukraine)\nWe point out that the variance of net-baryon distribution normalized by the Skellam distribu tion baseline\, $\\kappa_2[B-\\bar{B}]/B+\\bar{B}$\, is sensitive to the p ossible modification of (anti)baryon yields due to $B\\bar{B}$ annihilatio n in the hadronic phase. The corresponding measurements can thus place str ingent limits on the magnitude of the $B\\bar{B}$ annihilation and its inv erse reaction. We perform Monte Carlo simulations of the hadronic phase in Pb-Pb collisions at the LHC via the recently developed subensemble sample r + UrQMD afterburner and show that the effect survives in net-proton fluc tuations\, which are directly accessible experimentally. The available exp erimental data of the ALICE Collaboration on net-proton fluctuations disfa vors a notable suppression of (anti)baryon yields in $B\\bar{B}$ annihilat ions predicted by the present version of UrQMD if only global baryon conse rvation is incorporated. On the other hand\, the annihilations improve the data description when local baryon conservation is imposed. The two effec ts can be disentangled by measuring $\\kappa_2[B+\\bar{B}]/B+\\bar{B}$\, w hich at the LHC is notably suppressed by annihilations but virtually unaff ected by baryon number conservation.\n\nhttps://indico.bitp.kiev.ua/event/ 8/contributions/230/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/230/ END:VEVENT BEGIN:VEVENT SUMMARY:Phase diagram of interacting pion matter and isospin charge fluctu ations DTSTART;VALUE=DATE-TIME:20211222T121000Z DTEND;VALUE=DATE-TIME:20211222T123000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-223@indico.bitp.kiev.ua DESCRIPTION:Speakers: Roman Poberezhnyuk (Bogolyubov Institute for Theoret ical Physics of the National Academy of Sciences of Ukraine)\nEquation of state and electric (isospin) charge fluctuations are studied for matter co mposed of interacting pions. The pion matter is described by self interact ing scalar fields via a $\\phi^4-\\phi^6$ type Lagrangian. The mean-field approximation is used and interaction parameters are fixed by fitting lat tice QCD results on the isospin density as a function of the isospin chemi cal potential at zero temperature. Two scenarios for fixing the model para meters - with and without the first order phase transition are considered\ , both yielding a satisfactory description of the lattice data. Thermodyna mic functions and isospin charge fluctuations are studied and systematical ly compared for these two scenarios\, yielding qualitative differences in the behavior of isospin charge susceptibilities. These differences can be probed by lattice simulations at temperatures $T \n\nhttps://indico.bitp.k iev.ua/event/8/contributions/223/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/223/ END:VEVENT BEGIN:VEVENT SUMMARY:Influence of cluster polarization on spectrum and elastic processe s in $^6$LI DTSTART;VALUE=DATE-TIME:20211222T115000Z DTEND;VALUE=DATE-TIME:20211222T121000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-234@indico.bitp.kiev.ua DESCRIPTION:Speakers: Nursultan Kalzhigitov (Al-Farabi Kazakh National Uni versity)\nThe aim of the present report is to study nature of resonance st ate in $^6$Li within an extended three-cluster model. It is well-known tha t the nucleus $^6$Li has two sets of resonance states. The first set is fo rmed by low-energy resonance states which lie close to the α+d decay thre shold and are of positive parity. There are two very narrow and three broa d resonance states in the first set. The second set of resonance states co nsists of high-energy resonance states of negative parity. They are very b road and reside above the $^3$H+$^3$He decay threshold. Different microsco pic and semi-microscopic models have been used to study resonance states i n $^6$Li. As a rule\, they have been applied to investigate either low-ene rgy or only high-energy resonance states. In the present report we study b oth sets of resonance states within one microscopic model. This model was formulated in Ref. [1] and is a three-cluster version of the resonating gr oup method. To study resonance states of $^6$Li within a large energy rang e the model was advanced to take into account two three-cluster configurat ions α+p+n and t+d+p. This allows us to involve in calculations all domin ant binary channels\, namely\, α+d\, $^5$He+p\, $^5$Li+n and $^3$H+$^3$He . Besides\, these three-cluster configurations also allow us to describe m ore correctly (adequately) the internal structure of d\, $^5$He\, $^5$Li\, $^3$He which are represented as a two-cluster configuration p+n\, $^4$He+ n\, $^4$He+p\, d+p\, respectively. \nCalculations of discrete and continuo us spectrum states of $^6$Li are performed with a nucleon-nucleon potentia l which was suggested by Tang and coworkers and is known as the Minnesota potential [2]. Parameters of the model and the nucleon-nucleon potential w ere selected to reproduce the ground state energy of $^6$Li. The present m odel with these parameters fairly good reproduces the energies and widths of the observed resonance states. The dominant decay channels are found fo r all resonance states. The hierarchy of channels depending on their impac t on the energy of the ground and resonance states is established. It is s hown that the cluster polarization\, associated with the ability of cluste rs d\, $^5$He\, $^5$Li\, $^3$He to change their size and shape\, plays an important role in formation of the ground state and low- and high-energy r esonances in $^6$Li.\n\n[1] V. S. Vasilevsky\, F. Arickx\, J. Broeckhove\, and T. P. Kovalenko\, «A microscopic three-cluster model with nuclear po larization applied to the resonances of $^7$Be and the reaction $^6$Li(p\, $^3$He)$^4$He»\, Nucl. Phys. A\, vol. 824\, pp. 37-57\, 2009.\n\n[2] D. R . Thompson\, M. LeMere\, and Y. C. Tang\, «Systematic investigation of sc attering problems with the resonating-group method»\, Nucl. Phys.\, vol. A286\, pp. 53-66\, 1977.\n\nhttps://indico.bitp.kiev.ua/event/8/contributi ons/234/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/234/ END:VEVENT BEGIN:VEVENT SUMMARY:Relativistic density functional approach to a unified description of quark-hadron matter DTSTART;VALUE=DATE-TIME:20211222T113000Z DTEND;VALUE=DATE-TIME:20211222T115000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-222@indico.bitp.kiev.ua DESCRIPTION:Speakers: Oleksii Ivanytskyi (Bogolyubov Institute for Theoret ical Physics)\nThe principal element of a unified description of strongly interacting matter within effective theories is the hadronization of quark s at low temperatures and baryonic densities\, while the partonic degrees of freedom are being suppressed in this regime. I present a novel approach to attack this problem\, which is formulated based on a relativistic dens ity-functional motivated by the string-flip model. Dynamical restoration of chiral symmetry within this approach is ensured by construction of the density functional. The low density/temperature suppression of quark degre es of freedom is provided by increase of the corresponding self-energy alr eady at the mean-field level. I also discuss the connection of the present approach to a Nambu-Jona-Lasinio-type model with density dependent (pseud o-)scalar coupling. Supplemented with the vector repulsion and diquark pai ring channels it is applied to model cold quark matter. The corresponding couplings are limited by confronting the results of modeling compact star s with quark cores to the observational data. This allows to construct the mean-field phase diagram of strongly interacting matter. Effects of hadr onization of strongly interacting matter are considered as a result of qua rk correlations beyond the mean field. The correlations caused by (pseudo- )scalar interaction channels are considered within the Gaussian approxima tion. This explicitly introduces mesonic states into the model. Their cont ribution to the thermodynamic potential is analyzed within the Beth–Uhle nbeck framework. Due to the different response of the mass spectrum of bou nd and continuum states to changes of the medium properties the Mott disso ciation of mesonic bound states occurs and is interpreted as physical mech anism of the deconfinement transition.\n\nhttps://indico.bitp.kiev.ua/even t/8/contributions/222/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/222/ END:VEVENT BEGIN:VEVENT SUMMARY:Calculation of the values of the zonal component of the electric f ield and the velocity of transfer of the ionospheric plasma due to the ele ctromagnetic drift during strong magnetic storms on October 12\, 2021 and November 4\, 2021 DTSTART;VALUE=DATE-TIME:20211222T100500Z DTEND;VALUE=DATE-TIME:20211222T102500Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-237@indico.bitp.kiev.ua DESCRIPTION:Speakers: Vyacheslav Kolodyazhnyi (Institute of ionosphere\, N AS and MES of Ukraine\, Kharkiv\, Ukraine)\nIt is well known that\, under quiet geomagnetic conditions\, the contribution of magnetospheric sources to electric fields and currents at middle and low latitudes is small. Unde r undisturbed conditions\, the magnitude of the zonal component of the ele ctric field is several units of $mV/m$. Plasma transport in the ionosphere caused by these fields plays an insignificant role in contrast to plasma transport due to ambipolar diffusion and neutral (thermospheric) winds. Ho wever\, during magnetic storms\, the penetration of electric fields to the heights of the ionosphere of middle latitudes takes place and\, as a cons equence\, an increase in the plasma velocity is observed due to the electr omagnetic drift $v_{EB}$. In turn\, an increase in $v_{EB}$ leads to varia tions in the neutral wind velocity and\, as a consequence\, to a change in the parameters of the global thermospheric circulation. Such a change in the dynamic mode of the ionospheric plasma significantly affects the altit ude distribution of the ionospheric parameters.\nThe aim of this work is t o estimate the magnitude of the zonal component of the electric field in t he ionosphere over Central Europe during strong magnetic storms on October 12 and November 4\, 2021\, as well as to calculate the velocity of plasma transfer in crossed electric and magnetic fields.\nThe behavior of the io nospheric parameters was analyzed and the values of the zonal component of the electric field $E_y$ and the velocity of plasma transport due to the electromagnetic drift $v_{EB}$ were estimated during two strong magnetic s torms on October 12\, 2021 ($Kp_{max} = 6\, D_{st} = –64 ~nT$) and Novem ber 4\, 2021 ($Kp_{max} = 7\, D_{st} = –115 ~nT$).\nDuring the magnetic storm on October 12\, 2021\, the maximum value of $|E_y|$ was equal to $27 ~mV/m$\, and the drift velocity $v_{EB} ≈ –240~ m/s$. The magnetic st orm was accompanied by a strong negative ionospheric storm. According to t he ionosonde st. Pruhonice\, Czech Republic (50º N\, 14.6º E) during the main phase of the storm\, a significant decrease in $NmF2$ density by abo ut 60% was recorded\, and the height of $hmF2$ increased by about 40 km co mpared to the reference day.\nThe maximum value $|E_y|$ during the magneti c storm on November 4\, 2021\, it was $29~mV/m$\, and the plasma transfer velocity $v_{EB}$ reached almost –$260 ~m/s$. The magnetic storm on Nove mber 4\, 2021 was also accompanied by a negative ionospheric storm\, durin g which there was a decrease in the electron density at the maximum of the F2 layer of the ionosphere and a significant rise in the height $hmF2$ – by about 90 km.\nThe results of a comparative analysis of the experime ntal data of the st. Pruhonice ionosonde with calculations using the inter national global model of the ionosphere IRI-2016 and the regional model of the ionosphere CERIM IION\, developed at the Institute of Ionosphere\, ar e presented. It is shown that the IRI-2016 model\, even with the “F-peak storm model” option\, incorrectly reproduces the diurnal variations in both the electron density at the maximum of the F2 layer of the ionosphere and for the height of this maximum $hmF2$ under disturbed conditions. The regional model CERIM IION\, designed for calculating the parameters of th e ionosphere in quiet conditions\, in comparison with the IRI-2016 model\, gives a more reliable forecast of variations in the main parameters of th e F2 layer.\nIn general\, taking into account the effects of electric fiel ds during magnetic storms makes it possible to refine\, analyze and physic ally interpret variations in the parameters of dynamic processes in the io nospheric plasma.\n\nhttps://indico.bitp.kiev.ua/event/8/contributions/237 / LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/237/ END:VEVENT BEGIN:VEVENT SUMMARY:Impact of asymmetric bosonic dark matter on neutron star propertie s DTSTART;VALUE=DATE-TIME:20211222T094500Z DTEND;VALUE=DATE-TIME:20211222T100500Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-218@indico.bitp.kiev.ua DESCRIPTION:Speakers: Edoardo Giangrandi (Centre for Physics of the Univer sity of Coimbra\, Coimbra\, Portugal)\nWe study an accumulation of asymmet ric bosonic dark matter inside neutron stars and its further impact on sta r's evolution. We present the conditions at which dark matter particles te nd to condensate in a core of the star or create an extended halo. We show that dark matter condensed in a core leads to a decrease of the total gra vitational mass and tidal deformability compared to a pure baryonic star. In addition\, at some conditions self-gravitating dark matter can collapse gravitationally and form a black hole that can destroy the star. We study the range of particle mass\, coupling constant and fraction of dark matte r inside the neutron star that lead to the formation of a black hole insid e a compact star. By imposing an existing astrophysical and gravitational wave constraints we set a new limit on the mass and fraction of dark matte r particles.\n\nhttps://indico.bitp.kiev.ua/event/8/contributions/218/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/218/ END:VEVENT BEGIN:VEVENT SUMMARY:The new AGN search in SDSS «MаNGA» survey DTSTART;VALUE=DATE-TIME:20211222T092500Z DTEND;VALUE=DATE-TIME:20211222T094500Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-220@indico.bitp.kiev.ua DESCRIPTION:Speakers: Kateryna Vovk (Main Astronomical Observatory\, Natio nal Academy of Sciences of Ukraine\, MAO/NASU\, 27 Akademika Zabolotnoho St. 03143 Kyiv\, Ukraine)\nAiming for searching outflows in AGN host' plan e a sample of ~600 galaxies was created from SDSS Marvin 16th Data release . Profiles of [OIII]5007AA spectrum line were investigated by fitting two\ , three or four Gaussians. With significance of more then 3-sigma complica ted gaseous movements in some AGN hosts were revealed. The frequency of di fferent outflow structures were estimated.\n\nhttps://indico.bitp.kiev.ua/ event/8/contributions/220/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/220/ END:VEVENT BEGIN:VEVENT SUMMARY:Milky Way Globular Clusters: close encounter rates with each othe r and with the Central Supermassive Black Hole DTSTART;VALUE=DATE-TIME:20211222T090500Z DTEND;VALUE=DATE-TIME:20211222T092500Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-217@indico.bitp.kiev.ua DESCRIPTION:Speakers: Marina Ishchenko (Main Astronomical Observatory NAS of Ukraine)\nThe recent precise astrometric measurements by Gaia Data Rele ase 2 (DR2) provide a possibility to measure the mean proper motions for t he large sample of (~150) GCs of the Milky Way (MW)\, which makes it plaus ible to study the orbital evolution of the globular clusters (GCs) system as the whole. To explore the possible close encounters (i.e.\, possible c ollisions) between the GCs and Central Black Hole (CBH)\, we performed the orbital calculations in total of 152 GCs using our self-developed high-or der φ-GRAPE code. We integrated (up to 10 Gyr in look-back time) the orbi ts of objects with reliable positions and proper motions in five different external gravitational potential models. They were selected from Illustri s TNG-100 cosmological simulation and have a variable in time mass\, and s izes. Using complex criteria on impact factors\, half-mass radii and relat ive velocity for the collision’s detection\, we found approximately 45 p airs of possible GCs “collisions” for all the five external potential models. We estimated 6 close encounter events with CBH on separations less than 100 pc from the center. The GCs sample consists of NGC 6121\, NGC 65 44\, NGC 6642 passed close in all systems with five potential models\; Ter zan 9 and NGC 6981 - in systems with four potential models (not fully cros sing)\; Pal 2 - in systems with two potential models.\n\nhttps://indico.bi tp.kiev.ua/event/8/contributions/217/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/217/ END:VEVENT BEGIN:VEVENT SUMMARY:Multimessenger astroparticle physics DTSTART;VALUE=DATE-TIME:20211222T080000Z DTEND;VALUE=DATE-TIME:20211222T084500Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-240@indico.bitp.kiev.ua DESCRIPTION:Speakers: Andrii Neronov (Astronomy Department\, University of Geneva & Université de Paris\, CNRS\, Astropaticule et Cosmologie)\nhttp s://indico.bitp.kiev.ua/event/8/contributions/240/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/240/ END:VEVENT BEGIN:VEVENT SUMMARY:Large time and long distance asymptotics of the thermal correlator s of the impenetrable anyonic lattice gas DTSTART;VALUE=DATE-TIME:20211221T132000Z DTEND;VALUE=DATE-TIME:20211221T134000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-228@indico.bitp.kiev.ua DESCRIPTION:Speakers: Yurii Zhuravlov (Bogolyubov Institute for Theoretica l Physics of the National Academy of Sciences of Ukraine)\nWe study therma l correlation functions of the one-dimensional impenetrable lattice anyons . These correlation functions can be presented as a difference of two Fred holm determinants. To describe large time and long distance behavior of th ese objects we use effective form factor approach. The asymptotic behavior is different in the space-like and time-like regions. In particular\, in the time-like region we observe the additional power factor on top of the exponential decay. We argue that this result is universal as it is related to the discontinuous behavior of the phase shift function of the effectiv e fermions. At particular values of the anyonic parameter we recover asymp totics of spin-spin correlation functions in XXO quantum chain.\n\nhttps:/ /indico.bitp.kiev.ua/event/8/contributions/228/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/228/ END:VEVENT BEGIN:VEVENT SUMMARY:Calculation model of X-ray phase contrast image of tested structur e DTSTART;VALUE=DATE-TIME:20211221T130000Z DTEND;VALUE=DATE-TIME:20211221T132000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-233@indico.bitp.kiev.ua DESCRIPTION:Speakers: Artur Ovcharenko (Institute of Applied Physics NAS o f Ukraine\, Sumy\, Ukraine)\nThe X-ray phase contrast imaging (PCI) method allows to visualize the internal structure of objects with small density gradients with high spatial resolution. The PCI technique is based on the use of the phenomenon of X-ray refraction\, which leads to a change in the phase front of the wave that passed through the sample. As a result of su ch deformation of the phase front X-rays deviate from their primary direct ion at small angles\, the magnitude of which depends on the spatial distri bution of the density of matter in the object under study [1]. The phase s hift of X-rays can't be measured directly\, so it is converted into a inte nsity difference by specified ways that it can be detected. PCI technique can also be combined with tomographic methods to obtain a 3D-distribution of the refractive index in the sample.\nIn the presented research the calc ulation methods are considered for the diffraction result on the test stru cture. Each of sections of this structure changes the phase of the inciden t radiation in a specified manner. Due to the fact that Fraunhofer diffrac tion is observed at a considerable distance between source and screen\, it is one of the limit cases of the scalar Kirchhoff diffraction theory. A o ne-dimensional case of diffraction was considered at first\, where a linea r phase change occurred within each of the lattice periods. As shown by th e calculations for the phase lattice\, the obtained intensity distribution differs qualitatively from the previously considered case of the amplitud e lattice. Thus\, one can see the displacement of the position of the cent ral maximum distribution for case of a phase grating relatively the initia l position. Due to this\, the possibility is achieved for incident radiati on concentrating in the chosen position. Graphs of intensity distribution for different indicator of linear phase change\, as well as for different sizes of inhomogeneous section in the periodic structure of the phase latt ice are calculated [2]. The peculiarities of the intensity distribution of diffracted radiation for such test objects are shown.\n\n[1]. Paganin D. Coherent x-ray optics. Oxford University Press\, 2013. 424 p.\n[2]. Kolobr odov V.G. Applied diffraction optics: Handbook / V.G. Kolobrodov G.S\,Tymc huk – К.: NTUU „KPI”\, 2014. – 312 p.\n\nhttps://indico.bitp.kiev .ua/event/8/contributions/233/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/233/ END:VEVENT BEGIN:VEVENT SUMMARY:The governing quantitative characteristics of radiation-induced se gregation in Fe-Cr-Ni alloy DTSTART;VALUE=DATE-TIME:20211221T124000Z DTEND;VALUE=DATE-TIME:20211221T130000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-232@indico.bitp.kiev.ua DESCRIPTION:Speakers: Roman Skorokhod (Institute of Applied Physics of Nat ional Academy of Sciences of Ukraine\, Sumy\, Ukraine)\nA profound consequ ence of irradiation (neutron\, proton\, electron and heavy ion) of metal a lloys is the spatial redistribution of alloy components. As a result\, the re are enrichment or depletion of the main\, solute and impurity component s of the alloy near the defect sinks. This phenomenon is called radiation- induced segregation (RIS) and leads to degradation of mechanical and physi cochemical properties of materials.\n\nThe spatial and temporal evolution of the concentrations of alloy components $C_{k} $ $\\left(k=\\mathrm{Fe}\ ,\\\, \\mathrm{Cr}\,\\\, \\mathrm{Ni}\\right)$ and point defects (PD) (vac ancies $C_{\\mathit{v}} $ and interstitials $C_{i} $) in the ternary conce ntrated Fe-Cr-Ni alloys under irradiation is described by the system of fi ve coupled nonlinear partial differential equations [1-3]:\n$\\begin{equat ion} \n\\left\\{\\begin{array}{l} {\\frac{\\partial C_{k} }{\\partial t} = -\\mathbf{\\nabla}\\mathbf{J}_{k} \,} \\\\ {\\frac{\\partial C_{\\mathit{v }} }{\\partial t} =-\\mathbf{\\nabla}\\mathbf{J}_{v} +K_{0} -R_{iv} C_{\\m athit{v}} C_{i} -k_{v}^{2} D_{v} \\left(C_{v} -C_{v}^{eq} \\right)\,} \\\\ {\\frac{\\partial C_{i} }{\\partial t} =-\\mathbf{\\nabla }\\mathbf{J}_{i } +K_{0} -R_{iv} C_{\\mathit{v}} C_{i} -k_{i}^{2} D_{i} \\left(C_{i} -C_{i }^{eq} \\right).} \\end{array}\\right. \n\\end{equation}$\n \nwhere the f luxes of atoms species $k$ is $\\mathbf{J}_k$\, vacancies $\\mathbf{J}_{\\ mathit{v}} $ and interstitial $\\mathbf{J}_{i} $ defined as:\n\n$\\begin{e quation} \n\\mathbf{J}_{k} =-\\left(\\sum _{d=v\,i}d_{k\,d} C_{d} \\right )\\mathbf{\\nabla}C_{k} +C_{k} \\left(d_{k\,v} \\mathbf{\\nabla }C_{v} -d_ {k\,i} \\mathbf{\\nabla }C_{i} \\right)\, \n\\end{equation}$ \n$\\begin{eq uation} \n\\mathbf{J}_{v} =-\\sum _{k=\\mathrm{Fe}\,\\\, \\mathrm{Cr}\,\\\ , \\mathrm{Ni}}d_{k\,v} C_{k} \\mathbf{\\nabla }C_{v} +\\alpha C_{v} \\le ft(\\sum _{k=\\mathrm{Fe}\,\\\, \\mathrm{Cr}\,\\\, \\mathrm{Ni}}d_{k\,v} \ \mathbf{\\nabla}C_{k} \\right)\, \n\\end{equation}$ \n$\\begin{equation} \n\\mathbf{J}_{i} =-\\sum _{k=\\mathrm{Fe}\,\\\, \\mathrm{Cr}\,\\\, \\math rm{Ni}}d_{k\,i} C_{k} \\mathbf{\\nabla}C_{i} -\\alpha C_{i} \\left(\\sum _{k=\\mathrm{Fe}\,\\\, \\mathrm{Cr}\,\\\, \\mathrm{Ni}}d_{k\,i} \\mathbf{\ \nabla }C_{k} \\right)\, \n\\end{equation}$ \n$K_{0} $ is the production rate of radiation PD\, $R_{iv} $ is the recombination rate of PD\, $k_{v}^ {2} $ and $k_{i}^{2} $ are the sink strengths for vacancies and interstiti als respectively\, $C_{v}^{eq} $ and $C_{i}^{eq} $ are the equilibrium vac ancy and interstitial concentrations\, $D_{v} $ and $D_{i} $ are the diffu sion coefficients of vacancies and interstitial\, $d_{k\,v} $ and $d_{k\,i } $ are the diffusivity coefficients of vacancies and interstitial. The sy stem with the corresponding initial and boundary conditions is solved nume rically (a detailed solution algorithm is given in [2]). \nThe aim of the present paper is to calculate the governing quantitative characteristics o f RIS for Fe-20%Cr-8%Ni alloy under the irradiation. That are: concentrati on profiles of atoms species $k$ $C_{k} \\left(x\\right)$ and PD $C_{v\\le ft(i\\right)} \\left(x\\right)\\\, $\, surface concentration of atoms spec ies $k$ $C_{k}^{Surf} $\, the value of surface enrichment (depletion) of a toms species $k$ $\\Delta C_{k} $\, the full width of the concentration pr ofile of atoms species $k$ at half maximum enrichment (depletion) $\\mathr m{FWHM}_{k} $\, segregation area of atoms species $k$ $S_{k} $ and discrim inant of RIS of atoms species $k$ in a steady state $\\mathit{{\\mathfrak D}}_{k} $. For example\, production rate dependence of surface depletion\, $\\mathrm{FWHM} $ and segregation area for Cr and Ni are shown in Fig. 1. \n\n\nFig. 1. Production rate dependence of surface Cr depletion $\\Delta C_{\\mathrm{Cr}} $ and Ni enrichment $\\Delta C_{\\mathrm{Ni}} $ (solid li ne)\, $\\mathrm{FWHM}_{\\mathrm{Cr}} $ and $\\mathrm{FWHM}_{\\mathrm{Ni}} $ (dashed line) and segregation area of Cr $S_{\\mathrm{Cr}} $ and Ni $S_{ \\mathrm{Ni}} $ (dash-dotted line). Calculations were performed at tempera ture$T=400$~$\\mathrm{{}^\\circ}$C\, dose $D=10$~dpa (displacement per ato m).\n\nThe Authors acknowledge the support by the target research program of National Academy of Sciences of Ukraine “Nuclear and radiation techno logies for the energy sector and social needs” for 2019-2023.\n\n[1]. Wa s G.S. Fundamentals of Radiation Materials Science: Metals and Alloys (2nd ed.). New York: Springer-Verlag\, 2017. 1002 p.\n[2]. Skorokhod R.V.\, Ko ropov A.V. Modeling of Radiation-Induced Segregation in Fe–Cr–Ni Alloy s. Physics of the Solid State. 2019. Vol. 61\, P. 2269–2276.\n[3]. Korop ov O.V.\, Skorokhod R.V.\, in Proceedings of Ninth International Scientifi c-Practical Conference “Mathematics in Modern Technical University”\, Kyiv\, December\, 28–29\, 2020. Vinnytsia: Publisher FOP Kushnir Yu. V.\ , 2021. P. 80-89. (in Ukrainian)\n\nhttps://indico.bitp.kiev.ua/event/8/co ntributions/232/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/232/ END:VEVENT BEGIN:VEVENT SUMMARY:Entanglement measures of a frustrated spin-$1/2$ Heisenberg octahe dral chain within the localized-magnon approach DTSTART;VALUE=DATE-TIME:20211221T122000Z DTEND;VALUE=DATE-TIME:20211221T124000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-225@indico.bitp.kiev.ua DESCRIPTION:Speakers: Olesia Krupnitska (Institute for Condensed Matter Ph ysics\, NAS of Ukraine)\nWe consider the spin-1/2 antiferromagnetic Heisen berg model on the frustrated octahedral chain in a presence of the extern al magnetic field. In a previous study [1]\, it was shown that the localiz ed-magnon theory [2] can be modified for simpler calculation of concurrenc e [3]\, which may serve as a measure of the bipartite entanglement between nearest-neighbor and next-nearest-neighbor spins on squares of the octahe dral chain. The results presented in [1] confirmed a new paradigm of the l ocalized-magnons concept concerned with a simple calculation of entangleme nt measure. This study is devoted to further application of a modified loc alized-magnon theory for finding other entanglement measures. To be specif ic\, we will consider such measures of entanglement as entanglement of for mation and negativity [4-5]. It could be\, thus\, concluded that the local ized-magnon theory can be straightforwardly adapted in order to calculate the respective entanglement measures for a wide class of flat-band quantum Heisenberg antiferromagnets. \n\n[1] J. Strecka\, O. Krupnitska and J. Ri chter\, EPL\, ${\\bf 132}$ 30004 (2020).\n[2] J. Schulenburg et al.\, Phys . Rev. Lett. ${\\bf 88}$\, 167207 (2002).\n[3] L. Amico et al.\, Rev. Mod. Phys. ${\\bf 80}$\, 517 (2008).\n[4] A. Peres\, Phys. Rev. Lett. ${\\bf 7 7}$\, 1413 (1996).\n[5] G. Vidal and R.F. Werner\, Phys. Rev. A $\\bf65$\, 032314 (2002).\n\nhttps://indico.bitp.kiev.ua/event/8/contributions/225/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/225/ END:VEVENT BEGIN:VEVENT SUMMARY:The charge and the dipole moment of quantized vortex structures in superfluid systems DTSTART;VALUE=DATE-TIME:20211221T120000Z DTEND;VALUE=DATE-TIME:20211221T122000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-224@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)\nThe problem of the electric fields created outside a superfluid liquid when quantum vortices and vortex rings appear inside the system is solved. It is shown that in the presence of a magnetic field a quantum vo rtex line acquires a linear charge density. The value of the charge densit y depends on the angle between the circulation vector and the magnetic fie ld. It was found that a charge is associated with a rectilinear vortex fil ament\, and a dipole moment is associated with a vortex ring. It was found that the key role while observing of electric fields outside the system i s played by the shape of the surface that bounds the superfluid system. It was established that the polarization associated with the velocity field of the vortex ring does not cause the appearance of an electric field outs ide an infinite cylindrical capillary with a circular cross section in the case when the capillary axis coincides with the ring axis. If the system does not have such a high symmetry and the axis of the ring does not coinc ide with the axis of the capillary\, the electric field outside the system is nonzero. The considered vortex structures can be generated by flows an d can be associated with the transition of the system to a quantum turbule nt state. For a laminar counterflow state of a superfluid system in a cyli ndrical circular capillary the electric potential outside the system is id entically equal to zero [1\,2]. Therefore\, the predicted magneto-electric properties of quantum vortex structures can serve as a basis for creating a sensitive quantum turbulent state detector for superfluid systems.\n\n[ 1] S. I. Shevchenko and A. M. Konstantinov\, JETP Letters\, 109\, 790 (201 9).\n[2] S. I. Shevchenko and A. M. Konstantinov\, Low Temp. Phys. 46\, 48 (2020).\n\nhttps://indico.bitp.kiev.ua/event/8/contributions/224/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/224/ END:VEVENT BEGIN:VEVENT SUMMARY:Approaching the atomic radii from in a data-oriented way: how can we benefit from a set of 'useless' structural properties? DTSTART;VALUE=DATE-TIME:20211221T085000Z DTEND;VALUE=DATE-TIME:20211221T091000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-229@indico.bitp.kiev.ua DESCRIPTION:Speakers: Tymofii Nikolaienko (Taras Shevchenko National Unive rsity of Kyiv)\nWe report utilization of a collection of interatomic dista nces\, obtained from 28 710 molecules after optimizing their geometries wi th quantum-chemical methods\, to introduce a new set of atomic radii for H \, B\, C\, N\, O\, F\, Si\, P\, S\, Cl\, Ge\, As\, Se\, Br elements. This problem is tackled from a perspective which differs significantly from man y conventional approaches\, like van der Waals radii or the covalent ones\ , which typically focus on introducing the atomic radii as the descriptors tailored for modeling specific sort of atomic contacts or bonded states f ound in diatomic fragments respectively. In contrast to that\, we study th e possibility of finding the atomic radii as parameters of a linear machin e-learned binary classifier\, trained to distinguish between bonded and no n-bonded pairs of atoms [1]. We demonstrate\, that although the distances between non-bonded atomic pairs play an essential role in training this cl assifier\, the obtained radii still exhibit considerable similarities to t he conventional covalent ones [2]. We thereby provide an example for how a proper data-oriented treatment can turn seemingly useless data into the u seful one. Additional details on the procedure [3] used to create a datase t of interatomic distances in fully automated\, yet chemically sound manne r\, are discussed. \n\n\n**References**\n\n[1] T.Y. Nikolaienko and L.A. B ulavin\, *Comput. Theor. Chem.* (2021)\, 1204: 113389.\n[2] T.Y. Nikolaien ko\, V.S. Chuiko and L.A. Bulavin\, *Mol. Phys.* (2020)\, **118**: e174293 7.\n[3] T.Y. Nikolaienko\, V.S. Chuiko and L.A. Bulavin\, *Comput. Theor. Chem.* (2019)\, **1163**: 112508.\n\nhttps://indico.bitp.kiev.ua/event/8/c ontributions/229/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/229/ END:VEVENT BEGIN:VEVENT SUMMARY:Physical mechanism of signal processing in biological neural netwo rks DTSTART;VALUE=DATE-TIME:20211221T080500Z DTEND;VALUE=DATE-TIME:20211221T085000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-239@indico.bitp.kiev.ua DESCRIPTION:Speakers: Alexander Vidybida (Bogolyubov Institute for Theoret ical Physics of the NAS of Ukraine)\nhttps://indico.bitp.kiev.ua/event/8/c ontributions/239/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/239/ END:VEVENT BEGIN:VEVENT SUMMARY:Wave diagnostics of inhomogeneous inclusions in low-dimensional qu asi-periodic structures DTSTART;VALUE=DATE-TIME:20211221T093000Z DTEND;VALUE=DATE-TIME:20211221T095000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-235@indico.bitp.kiev.ua DESCRIPTION:Speakers: Liudmyla Sidletska (Odessa State Environmental Unive rsity)\nIn the classical work Rayleigh showed that a plane wave propagatin g in a one-dimensional periodic unbounded structure\, for some wavelengths \, undergoes total reflection at the boundaries of a fragment\, called in the modern terminology accepted in the theory of such structures\, called photonic crystals\, a forbidden band. In this case (by the Bloch – Floqu et theorem) the wave amplitude inside the periodic system decays exponenti ally [1].\nIn this paper\, we consider a quasi-one-dimensional\, semi-boun ded layered periodic structure\, in which the first (in order) layer has c haracteristics (refractive index\, dielectric constant) that differ from o ther elements. We postulate that such a construction can serve as a model\ , for example\, of a granular chain starting from an isotopic defect (or f rom an impurity particle).\nIn this work\, a criterion is established for the condensation of the spectrum near one of the boundaries of the forbidd en zone corresponding to the non-propagating wave mode. In a real prototyp e\, a granular chain\, such a mode (for example\, in an electromagnetic wa ve) is\, as it were\, "arrested" in a certain vicinity of the impurity.\nA s a result\, it was demonstrated how\, when the symmetry of the initial st ate of the system is violated\, say\, due to the formation of defects (or deterministic incorporation of impurities)\, it is possible to form expone ntially growing and decaying modes with the formation of a separate one lo calized in the vicinity of the defect. The established regularities can be used as the basis for wave diagnostics of impurity inclusions\, as well a s defects in quasi-one-dimensional quasi-periodic physical systems\, for e xample\, inhomogeneous low-dimensional crystal structures operating on the principle of a wave diode [2].\n\n[1] P.G. Kevrekidis. Non-linear waves i n lattices: Past\, present\, future. IMA J. Appl. Math. 2011. V. 76 (3). P. 389-423\; https://doi.org/10.1093/imamat/hxr015 \n[2] S. Kasap\, H. Rud a\, Y. Boucher. Cambridge Illustrated Handbook of Optoelectronics and Phot onics. - Cambridge\, 2009 . P. 352\n\nhttps://indico.bitp.kiev.ua/event/8/ contributions/235/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/235/ END:VEVENT BEGIN:VEVENT SUMMARY:Propagation processes of correlations in the system of hard sphere s DTSTART;VALUE=DATE-TIME:20211221T091000Z DTEND;VALUE=DATE-TIME:20211221T093000Z DTSTAMP;VALUE=DATE-TIME:20260723T004159Z UID:indico-contribution-8-227@indico.bitp.kiev.ua DESCRIPTION:Speakers: Igor Gapyak (Taras Shevchenko National University of Kyiv)\nIn this talk we consider an approach to the description of the evo lution of a state by means of both reduced distribution functions and redu ced correlation functions\, which is based on the dynamics of correlations in a system of hard spheres. It should be emphasized that the generating operators of solution expansions of the corresponding hierarchies of evolu tion equations are induced\nby the generating operators of an expansion of the Liouville hierarchy solution \nfor a sequence of correlation function s.\n$~~~~~~~$In the talk an approach to the description of the state evolu tion of a system of hard spheres by means of the state of a typical partic le determined by the generalized Enskog equation is also discussed or\, in other words\, the foundations of the correlations evolution description b y kinetic equations are considered.\n\nhttps://indico.bitp.kiev.ua/event/8 /contributions/227/ LOCATION:Online meeting URL:https://indico.bitp.kiev.ua/event/8/contributions/227/ END:VEVENT END:VCALENDAR