To the study of non-Gaussianity in two-field slow-roll inflation

TL;DR

This paper derives a general expression for second-order curvature perturbations in two-field slow-roll inflation and shows that significant non-Gaussianity arises only if nonadiabatic perturbations are present at the end of inflation.

Contribution

It provides explicit formulas for second-order curvature perturbations in two-field inflation and analyzes conditions for non-Gaussianity generation.

Findings

Significant non-Gaussianity requires nonadiabatic perturbations at inflation's end.

Explicit second-order expressions for specific potentials are derived.

Non-Gaussianity is linked to super-Hubble evolution of perturbations.

Abstract

The general expression for the second order large scale curvature perturbation in the form of a functional over a background solution is derived. The explicit expressions was obtained for two special forms of the inflationary potential. In the considered cases, it is shown that a significant level of non-Gaussianity can be generated during the super-Hubble evolution only if nonadiabatic perturbations are non-negligible at the end of inflation.