Entropy production and reheating at the chiral phase transition

TL;DR

This paper investigates entropy production during nonequilibrium chiral phase transitions in quark plasma, highlighting how dissipation and noise influence reheating, with potential experimental signatures in particle ratios.

Contribution

It models entropy production using a Langevin approach coupled with Bjorken dynamics, analyzing effects of dissipation and noise on reheating across different phase transition types.

Findings

Entropy increase ranges from 10% to 200% depending on transition type.

Reheating effects could be observed via pion-to-proton ratios.

Reheating is sensitive to the expansion rate of the plasma.

Abstract

We study the production of entropy in the context of a nonequilibrium chiral phase transition. The dynamical symmetry breaking is modeled by a Langevin equation for the order parameter coupled to the Bjorken dynamics of a quark plasma. We investigate the impact of dissipation and noise on the entropy and explore the possibility of reheating for crossover and first-order phase transitions, depending on the expansion rate of the fluid. The relative increase in S/N is estimated to range from 10% for a crossover to 200% for a first-order phase transition at low beam energies, which could be detected in the pion-to-proton ratio as a function of beam energy.