Effective Field Theory Approach to String Gas Cosmology

TL;DR

This paper develops a 4D effective field theory for string gas cosmology, analyzing radion stabilization and proposing a string-inspired dark matter model, with implications for early universe dynamics.

Contribution

It derives a low energy effective field theory for string gas cosmology and explores radion dynamics and dark matter scenarios within this framework.

Findings

Radion stabilization is not achieved at late times but radion rolls slowly.

A simple string-inspired dark matter model is proposed.

The scenario remains of interest despite the lack of radion stabilization.

Abstract

We derive the 4D low energy effective field theory for a closed string gas on a time dependent FRW background. We examine the solutions and find that although the Brandenberger-Vafa mechanism at late times no longer leads to radion stabilization, the radion rolls slowly enough that the scenario is still of interest. In particular, we find a simple example of the string inspired dark matter recently proposed by Gubser and Peebles.