Opening Remarks by the Director of the Bogolyubov Institute for Theoretical Physics, S.M. Perepelytsya
Physical systems in a noncommutative space with preserved time-reversal and rotational symmetries
Khrystyna Gnatenko
Professor Ivan Vakarchuk Department for Theoretical Physics, Ivan Franko National University of Lviv, 12, Drahomanov St., Lviv, 79005, Ukraine.
We consider a space with noncommutativity of coordinates and momenta with preserved time-reversal and rotational symmetries [1]....
Studying the Entanglement of Multiqubit States with Quantum Technologies
N. A. Susulovska, Kh. P. Gnatenko
Professor Ivan Vakarchuk Department for Theoretical Physics,
Ivan Franko National University of Lviv, Lviv 79005, Ukraine
The utilization of entangled multiqubit resource states is a cornerstone of practical quantum computing allowing for the development of innovative quantum...
Remote collection and analysis of light is highly important for a plethora of applications including spectroscopy, endoscopy, biosensing, quantum communications, etc. Commercial optical fibers are the best platform for this purpose due to their ability to operate in strongly limited and closed spaces (particularly, in-vivo). The payback of this advantage is the low coupling of the incident...
Hyperbolic metasurfaces are known for their dispersion and polarization properties, such as negative refraction, hyperlensing, enhanced spontaneous emission, etc [1]. The surface waves localized at hyperbolic metasurfaces are called hyperbolic plasmon-polaritons and exhibit a lot of potential applications for planar technologies [2].
In this work, we analyze the dependencies of the...
Chirality refers to the property of an object that cannot be superimposed on its mirror image. Despite having the same chemical structure, most chiral molecules, also known as enantiomers, exhibit significant differences in biological activity, being either the poison or the drug, depending on their handedness [1]. Detection and separation of chiral molecules are crucial across various fields,...
The miniaturization and flattening of modern optical devices demand tunable control over highly localized electromagnetic fields. While there is progress in the control of group and phase velocities of localized light, its polarization properties and directivity pattern are still difficult to manage.
Optical spin angular momentum (SAM) defines polarization properties of light [1]. In...
Structure and nuclear reactions in hypernuclear systems are highly relevant at present. The increased amount of new experimental data over the past decades supports such interest in these objects. The interaction of the Λ particles with nucleons is responsible for forming light and weakly bound hypernuclei. Among them is the $^7_{\Lambda}$Li hypernucleus. One of the interesting features of...
The study of reaction dynamics in nuclear and hypernuclear systems is one of the most interesting and relatively new areas of modern nuclear physics and astrophysics. Numerous experimental and theoretical investigations in this area provide a deeper understanding of the properties of dense nuclear matter, as well as the structure of unusual objects in interstellar space, such as neutron stars....
Although the Standard Model (SM) has proven remarkably effective in accounting for a wide range of experimental data from particle colliders, it remains an incomplete framework. It does not account for several key phenomena, such as the oscillations of active neutrinos, the observed matter–antimatter imbalance in the Universe, and the nature of dark matter. Consequently, the SM requires...
In many theoretical models describing the evolution of the early Universe, topological defects appear, in particular in the form of magnetic cosmic strings \cite{Vil}. String models are used not only in the physics of the early Universe, but also in the physics of gadrons and continuous media. In particular, structures analogous to cosmic strings arise in the theory of superconductivity. Here,...
Understanding the phase structure of strongly interacting matter is a central goal of ongoing and future heavy-ion experiments, such as RHIC's Beam Energy Scan (BES) and FAIR's Compressed Baryonic Matter (CBM) program. These efforts aim to explore the Quantum Chromodynamics (QCD) phase diagram at high baryon densities, where a critical point and a first-order phase transition are conjectured...
The thermodynamic properties of an interacting pion system composed of particles and antiparticles are studied at finite high temperatures and densities, which may arise in relativistic collisions of individual particles and entire atomic nuclei. Systems containing both particles and antiparticles are considered under the condition of isospin (charge) density conservation. The results are...
Fundamental questions on the nature of matter and energy have found answers thanks to the use of particle accelerators. However, the accelerating field in superconducting radio-frequency cavities due to electrical breakdown is limited to about 100 MV/m. This limits the amount of acceleration over any given length, requiring very long accelerators to reach high energies. To overcome this...
In heavy-ion collisions, as two nuclei go through each other and form hot and dense matter they also transfer some of the angular momentum to the fireball, resulting in the non-zero vorticity. The connection between the initial-state, equation of state and vorticity exists and is of special interest. In this case coarse-graining of non-central Au+Au heavy-ion collisions at $E_{lab}=1.23$...
Despite the undeniable success of the Standard Model of particle physics (SM), there remain several phenomena, such as neutrino oscillations, the baryon asymmetry of the Universe, and dark matter, that the SM fails to explain. These phenomena clearly indicate the need for an extension of the SM, most likely involving new particles beyond its current framework. However, there is also a...
The study investigates non-dissipative longitudinal current states in bilayer systems with pairing of spatially separated electrons and holes in the presence of a potential barrier that divides the system into two macroscopic regions. The longitudinal current flowing across this barrier is identified as the longitudinal Josephson effect, while the current between the electron and hole layers...
We study viscoelastic response in Weyl semimetals with broken time-reversal symmetry. The principal finding is that topology and anisotropy of the Fermi surface are manifested in the viscoelasticity tensor of the electron fluid. In the dynamic (interband) part of this tensor, the anisotropy leads to a qualitatively different, compared with isotropic models, scaling with frequency and the Fermi...
In connection with the development of quantum technologies, special attention has been paid to the study of quantum properties of hybrid systems based on magnonics [1]. One of the areas of use of magnons (spin excitations) may be related to transfer of information The development of quantum information technologies has shown that charged particles are not very convenient for transmitting...
Manipulation of nanoscale ferromagnetic stripes' magnetic structure can play a pivotal role in the development of high-density, ultrafast magnetic memory and offers a significant potential to enhance the performance of spintronic devices [1,2].
This work is devoted to the theoretical and numerical study of the domain wall motion in straight ferromagnetic nanostripes with variable cross...
On the way to modeling composite structures consisting of discrete conglomerations containing special impurities in order to create materials with predictable properties, the study of the relationships between microscopic (structural) parameters and macroscopic properties plays a key role. For example, the compressibility of granular media (as well as molecular solutions) is one of the key...
We calculated phonon dispersion for graphene with taken into consideration different numbers of nearest neighbors in the Born-von Karman model [1]. Values of force constants were taken from [2-3]. It was shown that quadratic dependence of ZA mode, predicted at [4], depends on set of interatomic force constants and not on number of nearest neighbors, as thought earlier [3]. Our results are in...
The results of THz radiation scattering experiments on granular composites are interpreted through a combined scenario of ballistic photon propagation and scattering. At low impurity concentrations, the refractive index varies linearly with concentration, indicating predominantly ballistic transport. As the impurity content increases, multiple scattering becomes more significant. However, near...
We will give an introduction to the use of topology as a way to understand certain condensed matter systems. To this end we choose some topics of current interest to the research community. One basic example is given by formulating the quantum Hall conductivity as a manifestation of the Gauss-Bonnet theorem. A slightly more sophisticated example that we will discuss, is the axion...
The Blume–Capel model, an extension of the Ising model with single-ion anisotropy, features a rich phase diagram with the first- and second-order phase transition lines intersecting at the tricritical point. While the exact solution is known in the
thermodynamic limit for a complete graph, finite-size effects remain less understood. This talk presents an overview of recent results obtained by...
Isomonodromic tau functions have explicit expressions as sums of c=1 conformal blocks (or Nekrasov functions), known as the Kyiv formulas, discovered by Gamayun, Iorgov, and Lisovyy. The zeros of these tau functions are described by classical, or c=∞ conformal blocks, also identified with the Painlevé action on the trajectory. We analyze an expansion of the tau function around its zero and...
We recover the predictions of CFT regarding the connection formulae for the family of Heun equations. Two methods of derivation of the connection coefficients are employed: the theorem of Schäfke and Schmidt that allows for a rigorous proof in some cases, as well as the analysis of the asymptotic behavior of the Floquet solutions. Both methods yield closed formulas in terms of continued...
We obtain relativistic Gaussian perturbation equations for osculating elements in Schwarzschild space-time background, for an arbitrary force not restricted to the equatorial plane. As an application, we solve the perturbation equations in linear approximation for force induced by the Kerr space-time as an expansion of the Schwarzschild space-time. For this case in post-Newtonian limit, we...
Recently, there were developed notion of irregular conformal blocks in two dimensional conformal field theory. It is believed that the conformal blocks are related to the isomondromic tau functions of Painvleve equations. I will review how it works on the concrete example of Painleve I equation. The main idea is that the isomondromic tau function of Painleve I equation is presented in the form...
Supersymmetric quantum field theories (SQFTs), particularly those with
N=2 supersymmetry in four dimensions, often exhibit intricate behaviors. Yet, their rich structures can be more tractable than those of their non-supersymmetric counterparts. Notably, their BPS sectors are governed by algebraic frameworks reminiscent of those in simpler holomorphic-topological models.
In this talk, I...
The statistical models of dimers belong to the class of so-called free fermionic exactly solvable models. This means, that every correlation function of local operators in this model can be computed by determinant of some matrix, and, moreover, can be expressed using only two-point functions, i.e. the Wick's contraction formula is satisfied. Many other models of statistical physics can be...
We study the impact of primordial magnetic fields on the global 21 cm signal during the Dark Ages. By modeling magnetic heating effects, we show that the signal is sensitive to PMFs amplitude and spectral index, offering a potential probe of early-universe magnetogenesis with upcoming 21 cm observations.
Electromagnetic fields of pulsars can generate coherent axion signals at their rotational frequencies, which may be detected by laboratory experiments—pulsarscopes. As a promising case study, we model axion emission from the well-studied Crab pulsar, predicting a signal at $f \approx 29.6$ Hz that would be present regardless of whether axions contribute to the dark matter abundance. We...
Among popular candidates for dark matter (DM) particles are weakly interacting massive particles (WIMPs) with masses of the order of 100 GeV, sterile right-handed neutrinos with masses of several keV, and axion-like particles with masses of $\mu$eV. We consider a model of ultralight dark matter (ULDM) because of its interesting phenomenology. ULDM is composed of bosonic particles with masses...
We present the first steps of a new approach aimed at improving photoionization analysis in dwarf galaxies by replacing unresolved features in chemodynamical simulations (Recchi and Hensler 2013) with physically consistent structures from hydrodynamical modeling. In previous works (Melekh et al. 2015, 2024), artificial thin dense shells (TDS) were introduced to emulate shock fronts that could...
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Photoionization modelling allows us to monitor the radiation transfer taking into account all important processes in nebular plasmas.
The spatial distributions of densities , chemical abundances and temperatures are needed for such modelling were obtained from chemodynamical simulations of dwarf galaxies. In present work we check the reliability of older version of CLOUDY C08.00 [1] in...
The recent surge in machine learning (ML) capabilities, most widely known through the ascent of large language models, mirrors the transformative impact of microprocessors in the 1970s, indicating a potential paradigm shift in the computational toolset used in scientific research workflows, including physics. This talk aims to ignite interest in investigating the multifaceted relationship...
The development of new molecules and the optimization of chemical synthesis depend on the ability to accurately estimate molecular energies and properties from structural information. In recent years, machine learning (ML) methods have emerged as powerful tools for addressing this task [1]. However, a persistent challenge is the illusion of improved accuracy that arises due to error...
We investigated classical machine learning algorithms for categorizing galaxy morphology using the Galaxy Zoo DECaLS dataset. It contains more than 300,000 photos of galaxies, from which we selected 50,000 images with the highest coincidence of human classification choice. Our methodology combined dimensionality reduction with subsequent classification. We evaluated five reduction techniques...
The integrated HydroKinetic Model (iHKM) is a key tool for simulating the complex dynamics of relativistic heavy-ion collisions. However, full-scale iHKM simulations are computationally demanding. This work presents a novel approach combining machine learning with iHKM to both infer optimal model parameters (such as viscosity and relaxation time) from experimental data and to approximate full...
The intriguing phenomenon of superconductivity has been extensively studied for over a century. Yet, a key challenge remains unresolved in practice: understanding and predicting the critical temperature $T_c$ of a superconductor. This issue is especially challenging for high-temperature superconductors (HTSC), which comprise diverse material classes and probably involve different electron...
A third to a half of solar radiation is reflected from a silicon surface of a bare solar cell. That is why a problem of creation additional anti-reflective coatings gathers lots of attention even today. In our submission, we demonstrate that a single patterned polycrystalline silicon layer can suppress average reflectance to $\approx 2\%$ at normal incidence and below 5 % up to $60{}^\circ$...
