Thermalization and isotropization in the AMY parton cascade ALPACA

TL;DR

This paper investigates thermalization and isotropization processes in the ALPACA parton cascade, demonstrating expected thermalization behavior and exploring initial anisotropic conditions relevant to high-energy QCD systems.

Contribution

It introduces the ALPACA kinetic theory framework and provides first insights into isotropization for Color Glass Condensate-like initial states.

Findings

System thermalizes as expected from analytical results.

Initial anisotropic conditions show qualitative isotropization behavior.

Overoccupied initial conditions relax towards thermal equilibrium.

Abstract

We look at thermalization and isotropization processes in the newly introduced AMY QCD kinetic theory parton cascade ALPACA. For thermalization, we consider the case of overoccupied initial conditions, and study the time evolution of the distribution as it relaxes to thermal equilibrium. We find that the system thermalizes as expected compared to known analytical results. For anisotropic systems, we take a first look at the qualitative behaviour of isotropization for Color Glass Condensate-like initial conditions in a homogeneous box with periodic boundary conditions.