Closer towards inflation in string theory

TL;DR

This paper explores how inflation can be realized within superstring theory by leveraging shift symmetry to control the inflaton mass, providing conditions on the superpotential for successful slow-roll inflation.

Contribution

It introduces a framework for achieving inflation in superstring theory by imposing shift symmetry and deriving conditions on the superpotential.

Findings

Shift symmetry suppresses the inflaton mass.

Conditions on the superpotential enable slow-roll inflation.

Natural realization of inflationary conditions in string theory.

Abstract

In brane inflation, the relative brane position in the bulk of a brane world is the inflaton. For branes moving in a compact manifold, the approximate translational (or shift) symmetry is necessary to suppress the inflaton mass, which then allows a slow-roll phase for enough inflation. Following recent works, we discuss how inflation may be achieved in superstring theory. Imposing the shift symmetry, we obtain the condition on the superpotential needed for inflation and suggest how this condition may be naturally satisfied.