T and S dualities and The cosmological evolution of the dilaton and the scale factors

TL;DR

This paper explores how S and T dualities influence the cosmological evolution of the dilaton and scale factors in string theory, revealing mechanisms for dilaton stabilization and duality-compatible actions.

Contribution

It demonstrates the impact of S and T dualities on dilaton gravity and identifies conditions under which duality invariances lead to stable cosmological models.

Findings

S duality partially decouples dilaton from scale factor evolution

Certain T duality invariant actions become compatible with S duality

Models show potential for dilaton stabilization in cosmology

Abstract

Cosmologically stabilizing radion along with the dilaton is one of the major concerns of low energy string theory. One can hope that T and S dualities can provide a plausible answer. In this work we study the impact of S and T duality invariances on dilaton gravity. We have shown various instances where physically interesting models arise as a result of imposing the mentioned invariances. In particular S duality has a very privileged effect in that the dilaton equations partially decouple from the evolution of the scale factors. This makes it easy to understand the general rules for the stabilization of the dilaton. We also show that certain T duality invariant actions become S duality invariance compatible. That is they mimic S duality when extra dimensions stabilize.