arXiv subjects

A. Meistrenko

Publications and source records attributed to A. Meistrenko.

3 recordsLinked to original sources

arXiv2022

Kinetics of the chiral phase transition in a quark-meson $σ$ model

Using the two-particle irreducible (2PI) $Φ$-functional formalism for self-consistent approximations of a linear-$σ$ model for quarks and mesons in and out of equilibrium, the build-up of fluctuations of net-baryon number during the time evolution of an expanding fireball is studied within a kinetic theory for the order parameter ($σ$ field) and quark distribution functions. Initializing the system with purely Gaussian fluctuations a fourth-order cumulant is temporarily built up due to the evolution of the $σ$-field. This is counterbalanced, however, by the dissipative evolution due to collisions between quarks, anti-quarks, mesons, and the mean field, depending on the speed of the fireball expansion.

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arXiv2017

Kinetics of the chiral phase transition in a linear $σ$ model

We study the dynamics of the chiral phase transition in a linear quark-meson $σ$ model using a novel approach based on semiclassical wave-particle duality. The quarks are treated as test particles in a Monte-Carlo simulation of elastic collisions and the coupling to the $σ$ meson, which is treated as a classical field. The exchange of energy and momentum between particles and fields is described in terms of appropriate Gaussian wave packets. It has been demonstrated that energy-momentum conservation and the principle of detailed balance are fulfilled, and that the dynamics leads to the correct equilibrium limit. First schematic studies of the dynamics of matter produced in heavy-ion collisions are presented.

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arXiv2013

Dynamics of the chiral phase transition

The intention of this study is the search for signatures of the chiral phase transition in heavy-ion collisions. To investigate the impact of fluctuations, e.g., of the baryon number, at the transition or at a critical point, the linear sigma model is treated in a dynamical (3+1)-dimensional numerical simulation. Chiral fields are approximated as classical mean fields, and quarks are described as quasi particles in a Vlasov equation. Additional dynamics is implemented by quark-quark and quark-sigma-field interactions. For a consistent description of field-particle interactions, a new Monte-Carlo-Langevin-like formalism has been developed and is discussed.

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