Plasmon mass scale in classical nonequilibrium gauge theory

TL;DR

This paper investigates the plasmon mass scale in classical nonequilibrium gauge theory using lattice simulations, comparing three methods to determine the mass and assessing their agreement.

Contribution

It introduces and compares three different methods to accurately determine the plasmon mass in classical Yang-Mills theory on a lattice.

Findings

The dispersion relation method agrees within 50% with other methods.

The study clarifies the limits of the quasiparticle picture in nonequilibrium gauge theories.

The work enhances understanding of the transition between classical and kinetic descriptions.

Abstract

Classical lattice Yang-Mills calculations provide a good way to understand different nonequilibrium phenomena in nonperturbatively overoccupied systems. Above the Debye scale the classical theory can be matched smoothly to kinetic theory. The aim of this work is to study the limits of this quasiparticle picture by determining the plasmon mass in classical real time Yang-Mills theory on a lattice in 3 spatial dimensions. We compare three methods to determine the plasmon mass: a hard thermal loop expression in terms of the particle distribution, an effective dispersion relation constructed from fields and their time derivatives, and by measuring oscillations between electric and magnetic field modes after artificially introducing a homogeneous color electric field. We find that a version of the dispersion relation that uses electric fields and their time derivatives agrees with the other methods within 50%.