Creating perturbations from a decaying field during inflation

TL;DR

This paper presents a model where a decaying field during inflation can generate all matter perturbations with specific spectral properties, challenging typical assumptions about such fields' roles.

Contribution

It introduces a novel scenario where a slowly rolling, decaying field produces observable matter perturbations with a red tilt and no isocurvature, expanding inflationary models.

Findings

Generates matter perturbations with a red-tilted spectrum

Produces no isocurvature perturbations

Allows for non-Gaussian fluctuations

Abstract

Typically the fluctuations generated from a decaying field during inflation do not contribute to the large scale structures. In this paper we provide an example where it is possible for a field which slowly rolls and then decays during inflation to create all the matter perturbations with a slightly red-tilted spectral index, with no isocurvature perturbations, and with a possibility of a departure from Gaussian fluctuations.