Bulk viscosity of N=2* plasma

TL;DR

This paper investigates the bulk viscosity of strongly coupled N=2* gauge theory plasma using gauge/gravity duality, confirming a viscosity bound and analyzing behavior near phase transitions.

Contribution

It provides the first detailed study of bulk viscosity in N=2* plasma across various mass deformations, confirming the viscosity bound and examining critical behavior.

Findings

Bulk viscosity confirms the proposed bound across mass ranges.

Near the phase transition, bulk viscosity increases but remains finite.

The theory exhibits a phase transition with divergent specific heat at T_c.

Abstract

We use gauge theory/string theory correspondence to study the bulk viscosity of strongly coupled, mass deformed SU(N_c) N=4 supersymmetric Yang-Mills plasma, also known as N=2^* gauge theory. For a wide range of masses we confirm the bulk viscosity bound proposed in arXiv:0708.3459. For a certain choice of masses, the theory undergoes a phase transition with divergent specific heat c_V ~ |1-T_c/T|^(-1/2). We show that, although bulk viscosity rapidly grows as T -> T_c, it remains finite in the vicinity of the critical point.