Microscopic Origin of Volume Modulus Inflation

TL;DR

This paper explores a string theory-based model where the volume of extra dimensions drives inflation, addressing the tension between high-scale inflation and low-energy supersymmetry by analyzing the scalar potential's microscopic origins.

Contribution

It provides a detailed microscopic derivation of the scalar potential for volume modulus inflation using non-perturbative and perturbative string effects, including anti-branes and hidden matter contributions.

Findings

The model achieves inflation with a single or two moduli setup.

The inflationary dynamics are sensitive to initial conditions and flux superpotential values.

The approach links the inflaton potential to string theory corrections and flux configurations.

Abstract

High-scale string inflationary models are in well-known tension with low-energy supersymmetry. A promising solution involves models where the inflaton is the volume of the extra dimensions so that the gravitino mass relaxes from large values during inflation to smaller values today. We describe a possible microscopic origin of the scalar potential of volume modulus inflation by exploiting non-perturbative effects, string loop and higher derivative perturbative corrections to the supergravity effective action together with contributions from anti-branes and charged hidden matter fields. We also analyse the relation between the size of the flux superpotential and the position of the late-time minimum and the inflection point around which inflation takes place. We perform a detailed study of the inflationary dynamics for a single modulus and a two moduli case where we also analyse the sensitivity of the cosmological observables on the choice of initial conditions.