Curvaton and the inhomogeneous end of inflation

TL;DR

This paper investigates how a single isocurvature field influences primordial density perturbations and non-Gaussianities through its dual role at the end of inflation and during curvaton decay in hybrid inflation models.

Contribution

It introduces a combined framework analyzing the effects of an inhomogeneous end of inflation and curvaton decay via a single isocurvature field.

Findings

Derived the non-Gaussianity parameter $f_{NL}$ for the model.

Reproduced standard end-of-inflation and curvaton results as special cases.

Showed the impact of decay timing on non-Gaussianity levels.

Abstract

We study the primordial density perturbations and non-Gaussianities generated from the combined effects of an inhomogeneous end of inflation and curvaton decay in hybrid inflation. This dual role is played by a single isocurvature field which is massless during inflation but acquire a mass at the end of inflation via the waterfall phase transition. We calculate the resulting primordial non-Gaussianity characterized by the non-linearity parameter, $f_{NL}$, recovering the usual end-of-inflation result when the field decays promptly and the usual curvaton result if the field decays sufficiently late.