arXiv subjects

S. Semenov

Publications and source records attributed to S. Semenov.

3 recordsLinked to original sources

arXiv2023

Landau Free Energy of small clusters beyond mean field approach

The Landau Free Energy determines the landscape of order parameter fluctuations that occur in a physical system at thermal equilibrium and, in particular, characterizes the critical phenomena. We propose a semi-analytical approach based on the Fluctuating Local Field method, which allows to estimate Landau Free Energy for small clusters with discrete (Ising model) and continuous (Heisenberg model) order parameter.

cond-mat.stat-mech↗

arXiv2020

Microwave Tomographic Imaging of Cerebrovascular Accidents by Using High-Performance Computing

The motivation of this work is the detection of cerebrovascular accidents by microwave tomographic imaging. This requires the solution of an inverse problem relying on a minimization algorithm (for example, gradient-based), where successive iterations consist in repeated solutions of a direct problem. The reconstruction algorithm is extremely computationally intensive and makes use of efficient parallel algorithms and high-performance computing. The feasibility of this type of imaging is conditioned on one hand by an accurate reconstruction of the material properties of the propagation medium and on the other hand by a considerable reduction in simulation time. Fulfilling these two requirements will enable a very rapid and accurate diagnosis. From the mathematical and numerical point of view, this means solving Maxwell's equations in time-harmonic regime by appropriate domain decomposition methods, which are naturally adapted to parallel architectures.

cs.CE↗

arXiv2005

Mass spectra of radially and orbitally excited states of mesons

Meson mass spectra, evaluated in the framework of the relativistic model of quasi-independent quarks, are presented. Mass values are obtained with the help of numerical calculations based on the Dirac equation and by phenomenological mass formulae. The Dirac equation involves the potential, which is sum of the vector quasi-Coulombic potential and the scalar linear rising confinement potential. The phenomenological mass formulae are applied to excited meson states consisting of u-, d-quarks and antiquarks with isotopical spin I=1. A comparison of the evaluated mass spectra with existing data is performed. Problems of identification of some meson states in vector and scalar channels are discussed.

hep-ph↗