Non-equilibrium cumulants within model A from crossover to first-order phase transition side

TL;DR

This paper investigates non-equilibrium cumulants of the chiral order parameter during phase transitions using Langevin dynamics, revealing memory effects and differences from equilibrium behavior, especially near first-order transitions.

Contribution

It introduces a detailed numerical study of non-equilibrium cumulants across different phase transition scenarios, highlighting their dynamic behavior and potential experimental signatures.

Findings

High-order cumulants differ from equilibrium predictions below the transition temperature.

Dynamical cumulants grow more intensively near first-order transitions.

Non-monotonic behavior of cumulants observed at large chemical potentials.

Abstract

We study the non-equilibrium cumulants of the chiral order parameter field ({\sigma} field) in different phase transition scenarios via Langevin dynamics. Cumulants up to fourth-order have been calculated based on the spacetimedependent {\sigma} configurations from the event-by-event numerical simulations. By limiting the cooling of the system in a Hubble-like way, the out-of-equilibrium cumulants illustrate clear memory effects during the evolution. Both the signs and the magnitudes of the high-order cumulants differ from the equilibrium ones below the phase transition temperature. Especially, the dynamical cumulants grow more intensively from the first-order phase transition side than they do from the crossover side. In addition, analysis of the high-order offequilibrium cumulants on the hypothetical freeze-out lines present non-monotonic curves in the large chemical potential region.