Exact braneworld cosmology induced from bulk black holes

TL;DR

This paper derives exact cosmological equations for a brane in a charged black hole bulk, revealing non-linear effects from the bulk Weyl tensor and connecting thermodynamics with a generalized Cardy-Verlinde formula.

Contribution

It introduces a new exact method for calculating brane energy density in black hole spacetimes and links bulk effects to brane cosmology and thermodynamics.

Findings

Bulk Weyl tensor induces non-linear terms in brane cosmology.

Exact thermodynamics and a generalized Cardy-Verlinde formula are established.

No ambiguity in splitting brane energy-momentum in black hole driven models.

Abstract

We use a new, exact approach in calculating the energy density measured by an observer living on a brane embedded in a charged black hole spacetime. We find that the bulk Weyl tensor gives rise to non-linear terms in the energy density and pressure in the FRW equations for the brane. Remarkably, these take exactly the same form as the ``unconventional'' terms found in the cosmology of branes embedded in pure AdS, with extra matter living on the brane. Black hole driven cosmologies have the benefit that there is no ambiguity in splitting the braneword energy momentum into tension and additional matter. We propose a new, enlarged relationship between the two descriptions of braneworld cosmology. We also study the exact thermodynamics of the field theory and present a generalised Cardy-Verlinde formula in this set up.