Curvaton Dynamics and the Non-Linearity Parameters in Curvaton Model

TL;DR

This paper explores how slight deviations from quadratic potential in the curvaton model affect non-linearity parameters, especially $g_{NL}$, with implications for axion-type models if large positive $g_{NL}$ is observed.

Contribution

It provides a detailed analysis of curvaton dynamics with non-quadratic potentials and highlights the impact on non-linearity parameters like $g_{NL}$, including the possibility of negative leading-order terms.

Findings

Non-linearity parameter $g_{NL}$ arises from curvaton self-interaction.

Leading order non-quadratic term can be negative in axion-type models.

Detection of large positive $g_{NL}$ favors axion-type curvaton models.

Abstract

We investigate the curvaton dynamics and the non-linearity parameters in curvaton model with potential slightly deviating from the quadratic form in detail. The non-linearity parameter $g_{NL}$ will show up due to the curvaton self-interaction. We also point out that the leading order of non-quadratic term in the curvaton potential can be negative, for example in the axion-type curvaton model. If a large positive $g_{NL}$ is detected, the axion-type curvaton model will be preferred.