Temperature dependence of bulk viscosity within lattice simulation of $SU(3)$--gluodynamics

TL;DR

This study investigates how the bulk viscosity of $SU(3)$-gluodynamics varies with temperature using lattice simulations, revealing a small ratio $ zeta/s$ at higher temperatures and a rapid increase near the transition, indicating strong correlations in QGP.

Contribution

The paper provides new lattice simulation data on the temperature dependence of bulk viscosity in $SU(3)$-gluodynamics, employing the Backus-Gilbert and Tikhonov methods for analysis.

Findings

$ zeta/s$ is small for $T/T_c extgreater 1.1-1.2$

$ zeta/s$ rapidly increases near the transition temperature

Results exceed perturbative predictions, indicating strong correlations

Abstract

In this paper the temperature dependence of the $SU(3)$--gluodynamics bulk viscosity is studied within lattice simulations. To carry out this study we measure the correlation function of the trace of the energy-momentum tensor for a set of temperatures within the range $T/T_c \in (0.9, 1.5)$. To extract the bulk viscosity from the correlation function we apply the Backus-Gilbert method and the Tikhonov regularization method. We show that the ratio $\zeta/s$ is small in the region $T/T_c \geqslant 1.1-1.2$ and in the vicinity of the transition $T/T_c \leqslant 1.1-1.2$ it quickly rises. Our results are in agreement with previous lattice studies and in a reasonable agreement with other phenomenological approaches. Obtained values of the bulk viscosity are significantly larger than perturbative results, what confirms that QGP is a strongly correlated system.