arXiv subjects

V. G. Baryakhtar

Publications and source records attributed to V. G. Baryakhtar.

3 recordsLinked to original sources

arXiv2013

Exchange relaxation as the mechanism of ultrafast spin reorientation in two-sublattice ferrimagnets

In the exchange approximation, an exact solution is obtained for the sublattice magnetizations evolution in a two-sublattice ferrimagnet. Nonlinear regimes of spin dynamics are found that include both the longitudinal and precessional evolution of the sublattice magnetizations, with the account taken of the exchange relaxation. In particular, those regimes describe the spin switching observed in the GdFeCo alloy under the influence of a femtosecond laser pulse.

cond-mat.str-el↗

arXiv2011

Quantum-thermal fluctuations of effective macroparameters and their correlations

The application of the conventional theory of macroparameter fluctuations has been shown to go beyond the framework of the thermodynamic description in a number of cases. The principles of the theory of quantum-thermal fluctuations of effective macroparameters and their correlations have been formulated. The theory satisfies the applicability conditions of equilibrium thermodynamics and is based on effective macroparameters, which take the integral stochastic action of the environment into account at any temperatures. The correlator of conjugate macroparameters, namely, the effective entropy and the effective temperature, has been calculated. The correlator was found to be proportional to the effective action which characterizes the stochastic environment. The pair correlators for the conjugate effective parameters entropy-temperature and coordinate-momentum have been demonstrated to depend linearly on the effective action, with their minimum values being determined by Planck's constant.

cond-mat.stat-mech↗

arXiv1999

Kinetic and Transport Equations for Localized Excitations in Sine-Gordon Model

We analyze the kinetic behavior of localized excitations - solitons, breathers and phonons - in Sine-Gordon model. Collision integrals for all type of localized excitation collision processes are constructed, and the kinetic equations are derived. We analyze the kinetic behavior of localized excitations - solitons, breathers and phonons - in Sine-Gordon model. Collision integrals for all type of localized excitation collision processes are constructed, and the kinetic equations are derived. We prove that the entropy production in the system of localized excitations takes place only in the case of inhomogeneous distribution of these excitations in real and phase spaces. We derive transport equations for soliton and breather densities, temperatures and mean velocities i.e. show that collisions of localized excitations lead to creation of diffusion, thermoconductivity and intrinsic friction processes. The diffusion coefficients for solitons and breathers, describing the diffusion processes in real and phase spaces, are calculated. It is shown that diffusion processes in real space are much faster than the diffusion processes in phase space.

solv-int↗