Moduli Stabilization in Brane Gas Cosmology with Superpotentials

TL;DR

This paper demonstrates the challenges of stabilizing key moduli in brane gas cosmology within superstring theory and explores how brane gases can aid in overcoming the overshoot problem in early universe models.

Contribution

It shows the impossibility of simultaneous dilaton and radion stabilization with general string and D-brane gases, and proposes a role for brane gases in assisting moduli stabilization.

Findings

Simultaneous stabilization of dilaton and radion is impossible with general brane gases.

Brane gases can help solve the overshoot problem in moduli potentials.

A modest energy density of specific brane gases can aid early universe stabilization.

Abstract

In the context of brane gas cosmology in superstring theory, we show why it is impossible to simultaneously stabilize the dilaton and the radion with a general gas of strings (including massless modes) and D-branes. Although this requires invoking a different mechanism to stabilize these moduli fields, we find that the brane gas can still play a crucial role in the early universe in assisting moduli stabilization. We show that a modest energy density of specific types of brane gas can solve the overshoot problem that typically afflicts potentials arising from gaugino condensation.