Hydrodynamics of simply spinning black holes & hydrodynamics for spinning quantum fluids

TL;DR

This paper explores the hydrodynamic properties of spinning black holes in AdS space and their dual quantum fluids, revealing anisotropic transport coefficients and stability conditions relevant to heavy ion collisions.

Contribution

It provides analytic expressions for anisotropic transport coefficients in spinning black hole dual fluids and extends known relations to include angular momentum dependence.

Findings

Shear viscosity to entropy density ratio varies with direction.

Hydrodynamic transport coefficients split into longitudinal and transverse groups.

Large spinning black holes are perturbatively stable below extremality.

Abstract

We find hydrodynamic behavior in large simply spinning five-dimensional Anti-de Sitter black holes. These are dual to spinning quantum fluids through the AdS/CFT correspondence constructed from string theory. Due to the spatial anisotropy introduced by the angular momentum in the system, hydrodynamic transport coefficients split into one group longitudinal and another transverse to the angular momentum. Analytic expressions are provided for the two shear viscosities, the longitudinal momentum diffusion coefficient, two speeds of sound, and two sound attenuation coefficients. Known relations between these coefficients are generalized to include dependence on angular momentum. The shear viscosity to entropy density ratio varies between zero and 1/(4$\pi$) depending on the direction of the shear. These results can be applied to heavy ion collisions, in which the most vortical fluid was reported recently. In passing, we show that large simply spinning five-dimensional Myers-Perry black holes are perturbatively stable for all angular momenta below extremality.