Effective dynamics of a nonabelian plasma out of equilibrium

TL;DR

This paper develops a nonlinear dissipative effective theory for nonabelian plasmas out of equilibrium, linking kinetic theory to a simplified model that can handle large gradients and anisotropies.

Contribution

It introduces a novel formalism derived from kinetic theory that does not rely on gradient expansion, enabling the study of highly anisotropic nonabelian plasma dynamics.

Findings

Provides a computationally efficient model for early-stage heavy ion collision dynamics.

Links kinetic distribution functions to effective theory variables via entropy production extremization.

Handles large momentum-space anisotropies without gradient expansion.

Abstract

Starting from kinetic theory, we obtain a nonlinear dissipative formalism describing the nonequilibrium evolution of scalar colored particles coupled selfconsistently to nonabelian classical gauge fields. The link between the one-particle distribution function of the kinetic description and the variables of the effective theory is determined by extremizing the entropy production. This method does not rely on the usual gradient expansion in fluid dynamic variables, and therefore the resulting effective theory can handle situations where these gradients (and hence the momentum-space anisotropies) are expected to be large. The formalism presented here, being computationally less demanding than kinetic theory, may be useful as a simplified model of the dynamics of color fields during the early stages of heavy ion collisions and in phenomena related to parton energy loss.