Bouncing Negative-Tension Branes

TL;DR

This paper investigates how negative-tension branes in braneworld models can avoid singularities by bouncing back, with analysis comparing 4D and 5D descriptions to validate the moduli space approximation.

Contribution

It demonstrates that negative-tension branes can bounce and avoid singularities under certain matter conditions, validating the moduli space approximation in this context.

Findings

Negative-tension branes can bounce and avoid singularities.

The moduli space approximation remains valid during the bounce.

Comparison between 4D and 5D descriptions confirms the robustness of the results.

Abstract

Braneworlds, understood here as double domain wall spacetimes, can be described in terms of a linear harmonic function, with kinks at the locations of the boundary branes. In a dynamical setting, there is therefore the risk that the boundary brane of negative tension, at whose location the value of the harmonic function is always lowest, can encounter a zero of this harmonic function, corresponding to the formation of a singularity. We show that for certain types of brane-bound matter this singularity can be avoided, and the negative-tension brane can shield the bulk spacetime from the singularity by bouncing back smoothly before reaching the singularity. In our analysis we compare the 5- and 4-dimensional descriptions of this phenomenon in order to determine the validity of the moduli space approximation.