Weak and strong coupling equilibration in nonabelian gauge theories

TL;DR

This paper compares the process of equilibration in nonabelian gauge theories at weak and strong coupling using kinetic theory and holography, revealing smooth connections in key physical quantities.

Contribution

It provides the first direct comparison of equilibration mechanisms at weak and strong coupling in the same setup, serving as a benchmark for heavy-ion collision studies.

Findings

Weak and strong coupling results can be connected by empirical power-laws.

Equilibration time and entropy production follow similar trends across couplings.

Viscosity shows a smooth transition between weak and strong coupling regimes.

Abstract

We present a direct comparison studying equilibration through kinetic theory at weak coupling and through holography at strong coupling in the same set-up. The set-up starts with a homogeneous thermal state, which then smoothly transitions through an out-of-equilibrium phase to an expanding system undergoing boost-invariant flow. This first apples-to-apples comparison of equilibration provides a benchmark for similar equilibration processes in heavy-ion collisions, where the equilibration mechanism is still under debate. We find that results at weak and strong coupling can be smoothly connected by simple, empirical power-laws for the viscosity, equilibration time and entropy production of the system.