Equilibration and relaxation times at the chiral phase transition including reheating

TL;DR

This paper studies the relaxation dynamics of the chiral order parameter near phase transitions, including reheating effects, revealing critical slowing down and phase coexistence through a Langevin approach.

Contribution

It introduces a Langevin model with reheating effects for the chiral phase transition, extending previous studies by conserving energy and analyzing different transition scenarios.

Findings

Critical slowing down at the critical point

Phase coexistence at the first order transition

Reheating effects influence relaxation dynamics

Abstract

We investigate the relaxational dynamics of the order parameter of chiral symmetry breaking, the sigma mean-field, with a heat bath consisting of quarks and antiquarks. A semiclassical stochastic Langevin equation of motion is obtained from the linear sigma model with constituent quarks. The equilibration of the system is studied for a first order phase transition and a critical point, where a different behavior is found. At the first order phase transition we observe the phase coexistence and at a critical point the phenomenon of critical slowing down with large relaxation times. We go beyond existing Langevin studies and include reheating of the heat bath by determining the energy dissipation during the relaxational process. The energy of the entire system is conserved. In a critical point scenario we again observe critical slowing down.