Horava-Witten Stability: eppur si muove

TL;DR

This paper presents exact time-dependent supergravity solutions involving brane interactions, highlighting potential instabilities and implications for models with negative tension branes in string theory.

Contribution

It constructs explicit time-dependent solutions including Horava-Witten and Randall-Sundrum models, revealing stability issues related to modulus stabilization and negative tension branes.

Findings

Solutions include supersymmetric brane configurations

Instabilities linked to unstabilized moduli fields

Negative tension branes may threaten model viability

Abstract

We construct exact time-dependent solutions of the supergravity equations of motion in which two initially non-singular branes, one with positive and the other with negative tension, move together and annihilate each other in an all-enveloping spacetime singularity. Among our solutions are the Horava-Witten solution of heterotic M-theory and a Randall-Sundrum I type solution, both of which are supersymmetric, i.e. BPS, in the time-independent case. In the absence of branes our solutions are of Kasner type, and the source of instability may ascribed to a failure to stabilise some of the modulus fields of the compactification. It also raises questions about the viability of models based on some sorts of negative tension brane.