Sound Mode Hydrodynamics from Bulk Scalar Fields

Understand

We study the hydrodynamic sound mode using gauge/gravity correspondence by examining a generic black brane background's response to perturbations.

• We assume that the background is generated by a single scalar field, and then generalize to the case of multiple scalar fields.
• The relevant differential equations obeyed by the gauge invariant variables are presented in both cases.
• Finally, we present an analytical solution to these equations in a special case; this solution allows us to determine the speed of sound and bulk viscosity for certain special metrics.