Primordial non-Gaussianity in noncanonical warm inflation: three- and four-point correlations

TL;DR

This paper analyzes the sources of non-Gaussianity in noncanonical warm inflation, focusing on three- and four-point correlations, and explores how different effects influence the non-Gaussian signals in this inflationary model.

Contribution

It provides a detailed comparison of three- and four-point correlation contributions to non-Gaussianity in noncanonical warm inflation, highlighting their relative importance in different regimes.

Findings

Four-point correlation dominates in canonical limit.

Three-point correlation overwhelms in strong noncanonical limit.

Field redefinition and thermal effects significantly influence non-Gaussianity.

Abstract

Non-Gaussianity generated in inflation can be contributed by two parts. The first part, denoted by $f_{NL}^{\delta N}$, is the contribution from four-point correlation of inflaton field which can be calculated using $\delta N$ formalism, and the second part, denoted by $f_{NL}^{int}$, is the contribution from the three-point correlation function of the inflaton field. We consider the two contributions to the non-Gaussianity in noncanonical warm inflation throughout (noncanonical warm inflation is a new inflationary model which is proposed in \cite{Zhang2014}). We find the two contributions are complementary to each other. The four-point correlation contribution to the non-Gaussianity is overwhelmed by the three-point one in strong noncanonical limit, while the conclusion is opposite in the canonical case. We also discuss the influence of the field redefinition, thermal dissipative effect and noncanonical effect to the non-Gaussianity in noncanonical warm inflation.