Stabilizing the Dilaton in Superstring Cosmology

TL;DR

This paper explores mechanisms to stabilize the dilaton field in superstring cosmology, demonstrating that stable solutions are more prevalent than previously believed, with implications for string theory models.

Contribution

It analyzes scalar potentials from gaugino condensates, showing that stable dilaton stabilization solutions are common in superstring cosmology.

Findings

Stable dilaton solutions are more common than expected.

Quasi scaling solutions can trap the dilaton in potential minima.

Dilaton stabilization is achievable in various gaugino condensation models.

Abstract

We address the important issue of stabilizing the dilaton in the context of superstring cosmology. Scalar potentials which arise out of gaugino condensates in string models are generally exponential in nature. In a cosmological setting this allows for the existence of quasi scaling solutions, in which the energy density of the scalar field can, for a period, become a fixed fraction of the background density, due to the friction of the background expansion. Eventually the field can be trapped in the minimum of its potential as it leaves the scaling regime. We investigate this possibility in various gaugino condensation models and show that stable solutions for the dilaton are far more common than one would have naively thought.