We investigate the hydrodynamic and quantum evolution of dark matter (DM) modeled as a Bose–Einstein condensate (BEC) with axion-like self-interaction within dwarf galaxies. The periodic nature of the interaction induces a multiphase halo structure with alternating stability zones, where low-density spatial tails undergo spinodal decomposition and fragment into clump- and foam-like structures...
The exchange of matter and energy between an open system and its surroundings triggers thermally activated spontaneous processes that drive entropy toward a maximum. Consequently, thermal equilibration is fundamentally entropy-driven, establishing a final equilibrium state whose population increases with temperature. In certain cases, this behavior manifests as an entropy-driven thermal...
An important problem in the statistical description of big data random sequences is identifying macroscopic characteristics that summarize the essential properties of the system while ignoring microscopic details. These characteristics are analogous to thermodynamic variables that describe the macroscopic state of a physical system composed of many interacting degrees of freedom. Markov chains...
A system consisting of a large number of relativistic charged particles is considered. An expression for the friction coefficient in momentum space has been derived based on particle dynamics under the action of the total force of binary interaction between charged particles. The derived formulas determine the particle friction coefficients in momentum space, both during the kinetic stage of...
Transport of a passive scalar in a given field is a common problem in plasma systems, the atmosphere, ocean flows, etc. It can be formulated as a problem to recover the temporal evolution of a particle ensemble in a given field based on known statistical characteristics of this field. An important peculiarity in such a system concerns the interplay of two time scales, namely the correlation...
The report presents results of the Heisenberg Cut study in the theory of quantum measurement. The solution to the problem was obtained thanks to perception of the impossibility of direct quanta measurement. An indirect test requires a deepening of the random variable definition via the Kolmogorov triad by the Frechet representation of a random element.
Measurement in general is a...
Measuring a quantum, as a purposeful activity of the Observer, consists in obtaining and supplementing information about the quantum or simply checking the property of the quantum for compliance with the expectation.
Here, a mathematically meaningful representation of the Observer is proposed, which is a set of devices capable of achieving the specified goal, and the algorithm for the...
We present a unified framework connecting Calabi--Yau geometry, singularity theory, and early-universe cosmology within heterotic and Type IIB string compactifications. Starting from the Tian--Yau threefold defined by its complete-intersection configuration matrix $P^3$ [3 0 1] ${P}^3$ [0 3 1], we demonstrate how a free $\mathbb{Z}_3$ quotient reduces the Euler characteristic to...
Ya. D. Krivenko-Emetov$^{1,2,3,*}$ and B. I. Sydorenko$^{2,\dagger}$
$^{1}$National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", Kyiv, Ukraine;$^{2}$Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kyiv, Ukraine;$^{3}$Taras Shevchenko National University of Kyiv, Kyiv, Ukraine$^{*}$y.kryvenko-emetov@kpi.ua; $^{\dagger}$former member of...
We construct a simple equation of state of strongly interacting matter at zero chemical potentials that provides a unified description of lattice QCD thermodynamics in terms of hadronic and partonic degrees of freedom. The hadronic phase is described by the quantum van der Waals hadron resonance gas, extended by excluded-volume repulsion between mesons, while the quark-gluon plasma is modeled...
Theoretical analysis of astrophysical S-factors of nuclear reactions
$^{7}$Be(n,$\alpha )^{4}$He and $^{7}$Be(n,p)$^{7}$Li
V.I. Zhaba, V.S. Vasilevsky, Yu.A. Lashko
Bogolyubov Institute for Theoretical Physics, National Academy of Sciences
of Ukraine
In this report, we study a range of reactions induced by the interactions $^{7}$Li+p, $^{7}$Be+n and $^{6}$Li+d. Special attention is...
We study an interacting relativistic system of charged bosons at finite temperature and fixed isospin density within a thermodynamically consistent mean-field approach. Two forms of repulsive self-interaction, $φ^4$ and $φ^6$, are considered. The interactions lead to a density-dependent effective mass $M$ of the bosonic quasiparticles and an associated excess-pressure contribution. The...
It was shown earlier that size effect of soft phonon dispersion is principally important in nanosized ferroics [1]. Also, the size and strain effects can determine the anomalous polarization reversal in strained thin films of van der Waals ferrielectrics [2]. It has been shown recently that the influence of the flexoelectric coupling (shortly “flexocoupling”) on the fluctuations of electric...
One of the problems of analyzing experimental electrophysical dependences is determining the parameters of the theoretical model that best reproduces the form of measured dielectric response of ferroelectric-dielectric nanocomposites. For complex nonlinear models, such a problem may have several close solutions, be sensitive to the initial approximation, and require significant computational...
Metallized DNA is of considerable interest due to its potential application in molecular electronics. Therefore, the fundamental properties of this system are of paramount interest, in particular those related to electronic structure and dynamics of metallized base pairs. In this work, two different structural motifs of Ag-DNA known from the experiment [1,2] were investigated: one that...
The complexes of monovalent ions (Li$^+$, Na$^+$, K$^+$) with DNA phosphate groups are considered in the present work. The complexes are studied from the simplest to the more complicated ones. In addition, chloride ions (Cl$^-$) and water molecules are introduced to make the complexes more realistic. Optimized geometries, interaction energies, and vibrational spectra are calculated using...
The DNA macromolecule has nanometer dimensions, a double helix structure consisting of chemically bonded atoms, and a large negative charge. Being in an aqueous environment or inside cells, the DNA macromolecule interacts mainly through electrostatic forces, hydrogen bonds, hydration and biochemical bonding, including medium ions, so the environment strongly influences DNA conformation,...
DNA is a strong polyanionic polyelectrolyte with the properties, which are largely governed by interactions with charged ions (counterions) in aqueous solution. Alkali metal cations differ substantially in ionic radius, charge density, and hydration enthalpy, which in turn determine how strongly they bind to the phosphate backbone, reorganize the surrounding hydration shell, and affect...
The non-stationary longitudinal Josephson effect in bilayer systems with pairing of spatially separated electrons and holes is investigated [1]. The tunneling current between two weakly coupled electron-hole condensates (right and left) is analyzed in the presence of an external voltage applied along the layers. Two limiting regimes are considered: the high-density regime, where pairing occurs...
Quantum chemical study of methanol interaction with a pyrene-based acid
Kremen O. S.1, Bychko I. B.2, Nikolaienko T.Y.3, Lobanov V. V.1, Strizhak P. E.2
1Chuiko Institute of Surface Chemistry of the NAS of Ukraine,
Oleh Mudrak Str., 17, Kyiv-03164, Ukraine, kremenoksana@ukr.net
2L. V. Pisarzhevskii Institute of Physical Chemistry of the NAS of Ukraine,
Prospect Nauki, 31,...
Organic solar cells based on non-fullerene acceptors (NFAs) are a promising direction in the development of organic photovoltaics due to the possibility of targeted molecular design and control of their electronic and optical properties. Particular attention is paid to A–D–A-type acceptors, including ITIC and its fluorinated derivatives, for which the introduction of fluorine atoms provides an...
A hypercomplex method for solving the piecewise-continuous Dirichlet problem for the Lamé system in domains with corner points has been developed, which is based on the representation of solutions using the components of a monogenic function in a commutative biharmonic algebra. Using a biharmonic integral of the Cauchy type, the Dirichlet problem has been reduced to a system of integral...
The Boltzmann equation [1] that describes the evolution of rarefied gases is one of the main equations of the kinetic theory of gases. For a model of rough spheres, the equation has the form:
\begin{equation}
D(f)= Q(f,f),
\end{equation}
where the left-hand side of the equation is the differential operator:
$$ D(f)\equiv\frac{\partial f}{\partial t}+\left(V,\frac{\partial f}{\partial...
By a copolynomial we mean here a linear functional on the space of polynomials $\mathbb{R}[x]$. The space of copolynomials is denoted by $\mathbb{R}[x]'$. If $T\in\mathbb{R}[x]'$ and $p\in\mathbb{R}[x]$, then the result of application of $T$ to $p$ is written as $(T,p)$. The derivative $T'$ of a copolynomial $T\in\mathbb{R}[x]'$ is defined in the same way as in the classical theory of...
We study a mathematical model describing viscous fingering induced by the chemical reaction $A+B \to C$, introduced in [T. Gerard and A. De Wit, Phys. Rev. E, 2009]. The model couples the concentrations of the reactants, $u(t,x,y)$ and $v(t,x,y)$, and their product, $w(t,x,y)$, with the pressure $p(t,x,y)$ and the two-dimensional velocity field $U=(U_1,U_2)$, and is given by
$ \nabla\cdot...
$\quad$Using the set of independent Symmetric Tamm-Dancoff (STD) type $q$-deformed quantum oscillators [1] with the standard linear-in-$N$ Hamiltonian, we construct respective gas of $q$-bosons. Such a deformed $q$-Bose gas model admits [2] exact analytic expressions for the $r$-particle momentum correlation function, and corresponding intercepts, of any $r$th order. This is the third example...
The speed of quantum state evolution is a fundamental characteristic of quantum dynamics. As shown in [1], for pure quantum states, it is directly governed by energy fluctuations. In the present work, we examine the speed of quantum evolution in a spin system described by the Ising model and subjected to a longitudinal magnetic field. We perform analytical derivations and quantum computing...
