Of Bounces, Branes and Bounds

TL;DR

This paper reevaluates brane world models in anti-de Sitter black hole backgrounds, showing that holographic viability depends on bulk charge size, challenging previous holographic (c-theorem) assessments.

Contribution

It introduces the causal entropy bound as a new criterion, demonstrating that brane worlds with sufficient bulk charge are holographically viable, contrary to prior holographic (c-theorem) conclusions.

Findings

Brane worlds can be holographically viable with adequate bulk charge.

The causal entropy bound offers a more reliable viability criterion.

Previous holographic assessments may be incomplete or misleading.

Abstract

Some recent studies have considered a Randall-Sundrum-like brane world evolving in the background of an anti-de Sitter Reissner-Nordstrom black hole. For this scenario, it has been shown that, when the bulk charge is non-vanishing, a singularity-free ``bounce'' universe will always be obtained. However, for the physically relevant case of a de Sitter brane world, we have recently argued that, from a holographic (c-theorem) perspective, such brane worlds may not be physically viable. In the current paper, we reconsider the validity of such models by appealing to the so-called ``causal entropy bound''. In this framework, a paradoxical outcome is obtained: these brane worlds are indeed holographically viable, provided that the bulk charge is not too small. We go on to argue that this new finding is likely the more reliable one.