Shear Viscosity of Yang-Mills Theory in the Confinement Phase

TL;DR

This paper uses a holographic model to analyze the shear viscosity and absorption cross section of pure Yang-Mills theory in the confinement phase, revealing temperature-independent behavior below the critical temperature.

Contribution

It introduces a simple holographic model with an infrared cutoff to estimate the confinement temperature and study shear viscosity and absorption cross section in the confinement phase.

Findings

Shear viscosity and absorption cross section are constant below T_c.

Critical temperature for gluon confinement is approximately 127 MeV.

Glueball states dominate the low-temperature phase.

Abstract

In terms of a simple holographic model, we study the absorption cross section and the shear viscosity of a pure Yang-Mills field at low temperature where the system is in the confinement phase. Then we expect that the glueball states are the dominant modes in this phase. In our holographic model an infrared cutoff r_m is introduced as a parameter which fixes the lowest mass of the glueball. As a result the critical temperature of gluon confinement T_c is estimated to be about 127 MeV. For T < T_c, we find that both the absorption cross section and the shear viscosity are independent of the temperature. Their values are frozen at the values corresponding to the critical point, for 0 < T < T_c. We discuss this behavior by considering the glueball mass and its temperature dependence.