Loop Corrections to Volume Moduli and Inflation in String Theory

TL;DR

This paper investigates how loop corrections affect the stabilization of volume moduli and the inflaton potential in string theory, focusing on toroidal orientifolds to understand the interplay between moduli stabilization and inflation.

Contribution

It provides a calculation of loop corrections to the superpotential and analyzes their impact on volume modulus stabilization and inflaton mass control in string inflation models.

Findings

Loop corrections modify the superpotential dependence on the volume modulus.

The potential explicitly involves the inflaton, allowing for potential mass tuning.

Control over the inflaton potential dependence enables better inflation model building.

Abstract

The recent progress in embedding inflation in string theory has made it clear that the problem of moduli stabilization cannot be ignored in this context. In many models a special role is played by the volume modulus, which is modified in the presence of mobile branes. The challenge is to stabilize this modified volume while keeping the inflaton mass small compared to the Hubble parameter. It is then crucial to know not only how the volume modulus is modified, but also to have control over the dependence of the potential on the inflaton field. We address these questions within a simple setting: toroidal N=1 type IIB orientifolds. We calculate corrections to the superpotential and show how the holomorphic dependence on the properly modified volume modulus arises. The potential then explicitly involves the inflaton, leaving room for lowering the inflaton mass through moderate fine-tuning of flux quantum numbers.