Black Branes in a Box: Hydrodynamics, Stability, and Criticality

Understand

We study the effective hydrodynamics of neutral black branes enclosed in a finite cylindrical cavity with Dirichlet boundary conditions.

• We focus on how the Gregory-Laflamme instability changes as we vary the cavity radius R.
• Fixing the metric at the cavity wall increases the rigidity of the black brane by hindering gradients of the redshift on the wall.
• In the effective fluid, this is reflected in the growth of the squared speed of sound.