Nonequilibrium Aspects of Quantum Field Theory

TL;DR

This paper introduces a method to analyze non-equilibrium quantum field simulations by examining the evolution of the Polyakov loop after rapid temperature changes, revealing different equilibration mechanisms.

Contribution

It develops a technique to extract equilibrium observables from non-equilibrium data and characterizes the transition between nucleation and spinodal decomposition in quantum field theory.

Findings

Observation of nucleation and spinodal decomposition in simulations

Exponential growth of Polyakov loop correlation function below critical wavenumber

Determination of effective potential and critical parameters as functions of temperature

Abstract

We have developed a method for extracting equilibrium observables from non-equilibrium simulations by rapidly changing the temperature and recording the subsequent evolution of the Polyakov loop. Both nucleation and spinodal decomposition are observed to occur. In the latter case the Polyakov loop correlation function shows exponential growth for wavenumbers less than or equal to the critical wavenumber k_c. We have constructed the bare as wee as the effective potential for the Polyakov loop, from which k_c and m_D/k_c can be extracted as a function of temperature. The shift from spinodal decomposition to nucleation as the dominant equilibration mechanism occurs at the spinodal temperature that separates these two regimes.