Generating the curvature perturbation with instant preheating

TL;DR

This paper proposes a novel mechanism where instant preheating converts isocurvature perturbations into curvature perturbations, especially relevant in models with significant kinetic energy at the end of inflation.

Contribution

It introduces a new end-of-inflation curvature perturbation generation mechanism applicable to brane inflation models with significant kinetic energy.

Findings

The mechanism effectively converts isocurvature to curvature perturbations.

Application to brane inflation models demonstrates its versatility.

Highlights the importance of instant preheating in curvature perturbation generation.

Abstract

A new mechanism for generating the curvature perturbation at the end of inflaton has been investigated. The dominant contribution to the primordial curvature perturbation may be generated during the period of instant preheating. The mechanism converts isocurvature perturbation related to a light field into curvature perturbation, where the ``light field'' is not the inflaton field. This mechanism is important in inflationary models where kinetic energy is significant at the end of inflaton. We show how one can apply this mechanism to various brane inflationary models.