Hybrid Inflation and Brane-Antibrane System

TL;DR

This paper explores a string theory-based hybrid inflation model involving brane-antibrane systems, where the interbrane distance drives inflation and tachyon dynamics end it, with results consistent with observations under certain conditions.

Contribution

It introduces a novel hybrid inflation scenario using brane-antibrane interactions within a Calabi-Yau compactification, linking geometry to inflationary parameters.

Findings

Sufficient e-foldings achieved with controlled initial conditions

Slow roll parameters mainly determined by geometry

Primordial fluctuations compatible with data at lower string scales

Abstract

We study a string theory inspired model for hybrid inflation in the context of a brane-antibrane system partially compactified on a compact submanifold of (a caricature of) a Calabi-Yau manifold. The interbrane distance acts as the inflaton, whereas the end of the inflationary epoch is brought about by the rapid rolling of the tachyon. The number of e-foldings is sufficiently large and is controlled by the initial conditions. The slow roll parameters, however, are essentially determined by the geometry and have little parametric dependence. Primordial density fluctuations can be made consistent with current data at the cost of reducing the string scale.