Metric anisotropies and nonequilibrium attractor for expanding plasma

TL;DR

This paper investigates how anisotropic expansion affects the evolution and attractor behavior of a relativistic plasma, providing insights into nonequilibrium dynamics relevant for heavy-ion collision experiments.

Contribution

It derives anisotropic hydrodynamics from the Boltzmann equation for Bianchi type I metrics and explores the impact of different expansion geometries on the nonequilibrium attractor.

Findings

Identification of the attractor in anisotropic expanding plasma

Effect of expansion geometry on approach to equilibrium

Implications for relativistic heavy-ion collision modeling

Abstract

We consider the evolution of a system of chargeless and massless particles in an anisotropic space-time given by the Bianchi type I metric. Specializing to the axis-symmetric case, we derive the framework of anisotropic hydrodynamics from the Boltzmann equation in the relaxation-time approximation. We consider the case of the axis-symmetric Kasner metric and study the approach to the emergent attractor in near and far-off-equilibrium regimes. Further, by relaxing the Kasner conditions on metric coefficients, we study the effect of expansion geometries on the far-off-equilibrium attractor and discuss its implications in the context of relativistic heavy-ion collisions.