Sound waves in strongly coupled non-conformal gauge theory plasma

TL;DR

This paper uses gauge/gravity duality to analyze sound wave propagation in a strongly coupled non-conformal plasma, calculating the speed of sound and bulk viscosity in N=2* supersymmetric Yang-Mills theory at high temperature.

Contribution

It provides the first computation of sound speed and bulk viscosity in a non-conformal gauge theory plasma using holographic methods.

Findings

Speed of sound matches between equation of state and hydrodynamic analysis.

Bulk viscosity is obtained from sound wave attenuation.

Results are relevant for understanding strongly coupled non-conformal plasmas.

Abstract

Using gauge theory/gravity duality we study sound wave propagation in strongly coupled non-conformal gauge theory plasma. We compute the speed of sound and the bulk viscosity of N=2^* supersymmetric SU(N_c) Yang-Mills plasma at a temperature much larger than the mass scale of the theory in the limit of large N_c and large 't Hooft coupling. The speed of sound is computed both from the equation of state and the hydrodynamic pole in the stress-energy tensor two-point correlation function. Both computations lead to the same result. Bulk viscosity is determined by computing the attenuation constant of the sound wave mode.