Trapped Inflation

TL;DR

Trapped inflation is a string-inspired inflationary mechanism where particle production on steep potentials slows the inflaton, producing sufficient e-foldings and distinctive non-Gaussian signatures in the density perturbations.

Contribution

This paper introduces a novel inflation model based on particle production that can occur on steep potentials, with new techniques for analyzing density perturbations and non-Gaussianity.

Findings

Achieves sixty e-foldings with correct density perturbation amplitude

Develops new methods for analyzing quantum fluctuations in particle production

Predicts significant equilateral non-Gaussianity in the power spectrum

Abstract

We analyze a distinctive mechanism for inflation in which particle production slows down a scalar field on a steep potential, and show how it descends from angular moduli in string compactifications. The analysis of density perturbations -- taking into account the integrated effect of the produced particles and their quantum fluctuations -- requires somewhat new techniques that we develop. We then determine the conditions for this effect to produce sixty e-foldings of inflation with the correct amplitude of density perturbations at the Gaussian level, and show that these requirements can be straightforwardly satisfied. Finally, we estimate the amplitude of the non-Gaussianity in the power spectrum and find a significant equilateral contribution.