Shear and bulk viscosities of the gluon plasma in a quasiparticle description

TL;DR

This paper models the shear and bulk viscosities of the gluon plasma using a quasiparticle approach, successfully matching perturbative and lattice QCD results across temperature regimes.

Contribution

It introduces a quasiparticle kinetic theory framework to compute transport coefficients, bridging perturbative and non-perturbative regimes.

Findings

Viscosities follow perturbative QCD dependencies at high temperatures.

Shear viscosity exhibits a minimum near the deconfinement transition.

Bulk viscosity is significant near the transition and decreases rapidly with temperature.

Abstract

Shear and bulk viscosities of deconfined gluonic matter are investigated within an effective kinetic theory by describing the strongly interacting medium phenomenologically in terms of quasiparticle excitations with medium-dependent self-energies. We show that the resulting transport coefficients reproduce the parametric dependencies on temperature and coupling obtained in perturbative QCD at large temperatures and small running coupling. The extrapolation into the non-perturbative regime results in a decreasing specific shear viscosity with decreasing temperature, exhibiting a minimum in the vicinity of the deconfinement transition, while the specific bulk viscosity is sizeable in this region falling off rapidly with increasing temperature. The temperature dependence of specific shear and bulk viscosities found within this quasiparticle description of the pure gluon plasma is in agreement with available lattice QCD results.