Evolution of non-Gaussianity in multi-scalar field models

TL;DR

This paper investigates how non-Gaussianity evolves in multi-scalar inflation models, examining the influence of potential features, the adiabatic limit process, and the methods for calculating the non-linearity parameter fNL.

Contribution

It provides new insights into the relationship between inflationary potential features and non-Gaussianity, and compares analytic and numerical approaches for calculating fNL.

Findings

Sign and peak of fNL are linked to potential features.

fNL sensitivity depends on the adiabatic limit process.

Both analytic and numerical tools are effective for calculating fNL.

Abstract

We study the evolution of non-Gaussianity in multiple-field inflationary models, focusing on three fundamental questions: (a) How is the sign and peak magnitude of the non-linearity parameter fNL related to generic features in the inflationary potential? (b) How sensitive is fNL to the process by which an adiabatic limit is reached, where the curvature perturbation becomes conserved? (c) For a given model, what is the appropriate tool -- analytic or numerical -- to calculate fNL at the adiabatic limit? We summarise recent results obtained by the authors and further elucidate them by considering an inflection point model.