Consistency relation and inflaton field redefinition in the delta N formalism

TL;DR

This paper analyzes the intrinsic non-Gaussianity in single-field inflation, demonstrating the consistency relation within the delta N formalism and proposing a field redefinition to eliminate intrinsic non-Gaussianity, refining local non-Gaussianity estimates.

Contribution

It shows how a specific field redefinition can nullify intrinsic non-Gaussianity, enhancing the delta N formalism's accuracy in inflationary models.

Findings

Recovered the consistency relation in delta N formalism

Identified a field redefinition that removes intrinsic non-Gaussianity

Improved estimates of local non-Gaussianity in single-field inflation

Abstract

We compute for general single-field inflation the intrinsic non-Gaussianity due to the self-interactions of the inflaton field in the squeezed limit. We recover the consistency relation in the context of the delta N formalism, and argue that there is a particular field redefinition that makes the intrinsic non-Gaussianity vanishing, thus improving the estimate of the local non-Gaussianity using the delta N formalism.