Loop corrections to volume moduli and inflation in string theory

Abstract

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