Holographic Screens and Transport Coefficients in the Fluid/Gravity Correspondence

TL;DR

This paper demonstrates that hypersurfaces in holography follow the same hydrodynamic equations with identical transport coefficients, confirming the exactness of the bulk viscosity formula across all orders and corrections.

Contribution

It proves the universality and exactness of fluid dynamics equations and transport coefficients for hypersurfaces in holography, including higher curvature corrections and superfluids.

Findings

Hypersurfaces evolve according to the same hydrodynamics equations at all orders.

Transport coefficients are identical for normal fluids and superfluids.

Bulk viscosity formula is exact, confirmed by null horizon dynamics.

Abstract

We consider in the framework of the fluid/gravity correspondence the dynamics of hypersurfaces located in the holographic radial direction at r = r_0. We prove that these hypersurfaces evolve, to all orders in the derivative expansion and including all higher curvature corrections, according to the same hydrodynamics equations with identical transport coefficients. The analysis is carried out for normal fluids as well as for superfluids. Consequently, this proves the exactness of the bulk viscosity formula derived in arXiv:1103.1657 via the null horizon dynamics.