Successfully combining SUGRA hybrid inflation and moduli stabilisation

TL;DR

This paper demonstrates that combining SUGRA hybrid inflation with moduli stabilisation via adding Kahler functions, rather than superpotentials, yields a viable model that overcomes typical inflationary potential corrections from sector interactions.

Contribution

It introduces a novel approach of combining sectors through Kahler functions, allowing for compatible inflation and moduli stabilisation in supergravity models.

Findings

Viable combined model achieved using Kahler functions

Interaction restrictions on moduli stabilisation mechanisms

Moduli stabilisation scale can be below inflationary energy scale

Abstract

Inflation and moduli stabilisation mechanisms work well independently, and many string-motivated supergravity models have been proposed for them. However a complete theory will contain both, and there will be (gravitational) interactions between the two sectors. These give corrections to the inflaton potential, which generically ruin inflation. This holds true even for fine-tuned moduli stabilisation schemes. Following a suggestion by 0712.3460, we show that a viable combined model can be obtained if it is the Kahler functions (G= K+\ln |W|^2) of the two sectors that are added, rather than the superpotentials (as is usually done). Interaction between the two sectors does still impose some restrictions on the moduli stabilisation mechanism, which are derived. Significantly, we find that the (post-inflation) moduli stabilisation scale no longer needs to be above the inflationary energy scale.