arXiv subjects

Yuri A. Markov

Publications and source records attributed to Yuri A. Markov.

5 recordsLinked to original sources

arXiv2016

Mapping between the classical and pseudoclassical models of a relativistic spinning particle in external bosonic and fermionic fields. II

The exact solution of a system of bilinear identities derived in the first part of our work [Nucl.Phys.A 938 (2015) 59] for the case of real Grassmann-odd tensor aggregate of the type $(S,V_μ,\!\,^{\ast}T_{μν},A_μ, P)$ is obtained. The consistency of the solution with a corresponding system of bilinear identities including both the tensor variables and their derivatives $(\dot{S},\dot{V}_μ,\!\,^{\ast}\dot{T}_{μν},\dot{A}_μ,\dot{P})$ is considered. The alternative approach in solving of the algebraic system based on introducing complex tensor quantities is discussed. This solution is used in constructing the mapping of the interaction terms of spinning particle with a background (Majorana) fermion field $Ψ^{i}_{{\rm M}\hspace{0.02cm}α}(x)$. A way of the extension of the obtained results for the case of the Dirac spinors $(ψ_{{\rm D}\hspace{0.03cm}α},θ_{{\rm D}\hspace{0.03cm}α})$ and a background Dirac field $Ψ^{i}_{{\rm D}\hspace{0.03cm}α}(x)$, is suggested. It is shown that for the construction of one-to-one correspondence between the most general spinors and the tensor variables, we need a four-fold increase of the number of the tensor ones. A connection with the higher-order derivative Lagrangians for a point particle and in particular, with the Lagrangian suggested by A.M. Polyakov, is proposed.

hep-th↗

arXiv2016

Mapping between the classical and pseudoclassical models of a relativistic spinning particle in external bosonic and fermionic fields. I

The problem on mapping between two Lagrangian descriptions (using a commuting $c$-number spinor $ψ_α$ or anticommuting pseudovector $ξ_μ$ and pseudoscalar $ξ_5$ variables) of the spin degrees of freedom of a color spinning massive particle interacting with background non-Abelian gauge field, is considered. A general analysis of the mapping between a pair of {\it Majorana} spinors $(ψ_α,θ_α)$ ($θ_α$ is some auxiliary anticommuting spinor) and a real anticommuting tensor aggregate $(S,V_μ,\!\,^{\ast}T_{μν},A_μ,P)$, is presented. A complete system of bilinear relations between the tensor quantities, is obtained. The analysis we have given is used for the above problem of the equivalence of two different ways of describing the spin degrees of freedom of the relativistic particle. The mapping of the kinetic term $(i\hbar/2)(\barθθ) (\dot{\barψ}ψ-\barψ\dotψ)$, the term $(1/e)(\barθθ)\dot{x}_μ(\barψγ^μψ)$ that provides a couple of the spinning variable $ψ$ and the particle velocity $\dot{x}_μ$, and the interaction term $\hbar(\barθθ)Q^{a}F_{μν}^a (\barψσ^{μν}ψ)$ with an external non-Abelian gauge field, are considered in detail. In the former case a corresponding system of bilinear identities including both the tensor variables and their derivatives $(\dot{S},\dot{V}_μ,\!\,^{\ast}\dot{T}_{μν},\dot{A}_μ, \dot{P})$, is defined. A detailed analysis of the local bosonic symmetry of the Lagrangian with the commuting spinor $ψ_α$, is carried out. A connection of this symmetry with the local SUSY transformation of the Lagrangian containing anticommuting pseudovector and pseudoscalar variables, is considered.

hep-th↗

arXiv2011

Equations of motion for a classical color particle in background non-Abelian fermionic and bosonic fields: Inclusion of pseudoclassical spin

A generalization of the Lagrangian introduced earlier in [2011 {\it J. Phys. G} ${\bf 37}$ 105001] for a classical color spinning particle interacting with background non-Abelian gauge and fermion fields for purpose of considering a change in time of the spin particle degree of freedom, is suggested. In the case under consideration the spin degree of freedom is described by a commuting $c$-number Dirac spinor $ψ_α$. A mapping of this spinor into new variables: anticommuting pseudovector $ξ_μ$ and pseudoscalar $ξ_5$ commonly used in a description of the spin degree of freedom of a massive spin-1/2 particle, is constructed. An analysis of one-to-one correspondence of this mapping is given. It is shown that for the one-to-one correspondence it is necessary to extend a class of real tensor quantities including besides $ξ_μ$ and $ξ_5$, also odd vector $\hatξ_μ$, scalar $\hatξ_5$, and (dual) pseudotensor $^{\ast}ζ_{μν}$. In addition, it is shown that it is necessary either to restrict a class of the initial spinor $ψ_α$ to Majorana one or to double the number of variables in the tensor aggregate $(ξ_μ,\,ξ_5,, ^{\ast}ζ_{μν},\,\hatξ_μ,\,\hatξ_5)$. Various special cases of the desired mapping are considered. In particular, a connection with the Lagrangian suggested by A.M. Polyakov, is studied. It is also offered the way of obtaining the supersymmetric Lagrangian in terms of the even $ψ_α$ and odd $θ_α$ spinors. The map of the Lagrandian leads to local SUSY Lagrangian in terms of $ξ_μ$ and $ξ_5$.

hep-th↗

arXiv2010

The equations of motion for a classical color particle in background non-Abelian bosonic and fermionic fields

Based on the most general principles of reality, gauge and reparametrization invariance, a problem of constructing the action describing dynamics of a classical color-charged particle interacting with background non-Abelian gauge and fermion fields is considered. The cases of the linear and quadratic dependence of a Lagrangian on a background fermion field are discussed. It is shown that in both cases in general there exists an infinite number of interaction terms, which should be included in the Lagrangian in question. From a simple iteration scheme, examples of the construction of the first few gauge-covariant currents and sources induced by a moving particle with non-Abelian charge are given. It is shown that these quantities, by a suitable choice of parameters, exactly reproduce additional currents and sources previously obtained in [Yu.A. Markov, M.A. Markova, Nucl. Phys. A 784 (2007) 443] on the basis of heuristic considerations.

hep-th↗

arXiv2010

On the fluctuation-dissipation theorem for soft fermionic excitations in a hot QCD plasma

We discuss two ways of deriving the fluctuation-dissipation theorem (FDT) for soft fermion excitations in a hot non-Abelian plasma being in a thermal equilibrium. The first of them is based on the extended (pseudo)classical model in describing a quark-gluon plasma suggested in [Yu.A. Markov, M.A. Markova, Nucl. Phys. A {\bf 784} (2007) 443], while the second one rests on the standard technique of calculation of the FDT for thermodynamically equilibrium systems. We show that full accounting all subtleties that are common to the fermion system under consideration, results in perfect coincidence of thus obtained FDTs. This provides a rather strong argument for the validity of the pseudoclassical model suggested.

hep-ph↗