Modular Cosmology

TL;DR

This paper explores the role of moduli fields in string theory as natural inflaton candidates, proposing models for inflation at high scales and addressing related scale hierarchies, but leaves some issues unresolved.

Contribution

It introduces a novel cosmological framework where moduli drive inflation at the top of domain walls, and proposes models to explain scale differences and stabilize the dilaton.

Findings

Inflation can occur at the top of domain walls driven by moduli.

Microwave background fluctuations constrain inflationary scale.

Models are proposed to explain scale hierarchies and dilaton stabilization.

Abstract

An exploratory study of the cosmology of moduli in string theory. Moduli are argued to be natural inflaton fields and lead to a robust inflationary cosmology in which inflation takes place at the top of domain walls. The amplitude of microwave background fluctuations constrains the dynamics responsible for inflation to take place at a higher scale than supersymmetry breaking. Models explaining this difference in scales and also preventing the dilaton from running to infinity are proposed. The problem of dilaton domination of the energy density of the universe is not resolved.