Instability of the Time Dependent Horava-Witten Model

TL;DR

This paper investigates the stability of the time-dependent Hořava-Witten model by analyzing scalar perturbations, revealing stability during non-singular periods and identifying signals of impending singularity through oscillation frequencies.

Contribution

It provides the first detailed analysis of scalar perturbations in the time-dependent Hořava-Witten model, linking oscillation behavior to the approach of singularities.

Findings

Model remains stable during non-singular epochs

Scalar oscillation frequencies indicate proximity to singularity

Oscillations can serve as a diagnostic for impending big crunch

Abstract

We consider scalar perturbations in the time-dependent Ho\u{r}ava-Witten Model in order to probe its stability. We show that during the non-singular epoque the model evolves without instabilities until it encounters the curvature singularity where a big crunch is supposed to occur. We compute the frequencies of the scalar field oscillation during the stable period and show how the oscillations can be used to prove the presence of such a singularity.