String Theory and the Early Universe: Constraints and Opportunities

TL;DR

This paper discusses the relevance of string theory to early universe cosmology, focusing on inflation, CMB tensor modes, and reheating, highlighting potential constraints and opportunities for integrating string theory insights.

Contribution

It provides a concise overview of how string theory can inform and constrain models of the early universe, addressing skepticism within the cosmology community.

Findings

String theory offers potential explanations for inflationary dynamics.

Constraints on string-inspired models from CMB observations.

Opportunities for future research at the intersection of string theory and cosmology.

Abstract

This is a short account, based on a talk given at the 2024 Moriond Cosmology Conference, of where and why string theory matters in early universe cosmology. It is written for a cosmology audience predisposed to be at best sceptical, and at worst contemptuous, of the notion that either quantum gravity or string theory has any relevance for their discipline. I cover inflation, CMB tensor modes, extended kination or tracker epochs and reheating.