Contributions of stochastic background fields to the shear and bulk viscosities of the gluon plasma

TL;DR

This paper calculates how confining and nonconfining stochastic background fields influence the shear and bulk viscosities of the gluon plasma in SU(3) Yang-Mills theory, highlighting the impact of nonconfining interactions.

Contribution

It introduces a calculation of nonperturbative contributions from stochastic background fields to viscosities, including the effect of nonconfining self-interactions, in SU(3) Yang-Mills theory.

Findings

Nonconfining self-interactions reduce viscosities by about 15%.

Nonperturbative contributions are comparable to perturbative and AdS/CFT predictions.

The ratios to entropy density are consistent with existing theoretical results.

Abstract

The contributions of confining as well as nonconfining nonperturbative self-interactions of stochastic background fields to the shear and bulk viscosities of the gluon plasma in SU(3) Yang-Mills theory are calculated. The nonconfining self-interactions change (specifically, diminish) the values of the shear and bulk viscosities by 15%, that is close to the 17% which the strength of the nonconfining self-interactions amounts of the full strength of nonperturbative self-interactions. The ratios to the entropy density of the obtained nonperturbative contributions to the shear and bulk viscosities are compared with the results of perturbation theory and the predictions of {\cal N}=4 SYM.