Primordial curvature perturbation during and at the end of multi-field inflation

TL;DR

This paper derives a general formula for primordial curvature perturbations in multi-field inflation, analyzing their evolution during and at the end of inflation, with explicit results for two-field models.

Contribution

It provides a comprehensive analytic framework for calculating curvature perturbations in multi-field inflation, including effects at the end of inflation, for separable potentials.

Findings

Derived a general formula for curvature perturbation during multi-field inflation.

Provided explicit expressions for power spectrum, spectral tilt, and non-Gaussianity.

Applied formulas to specific two-field inflation models.

Abstract

We study the generation of the primordial curvature perturbation in multi-field inflation. Considering both the evolution of the perturbation during inflation and the effects generated at the end of inflation, we present a general formula for the curvature perturbation. We provide the analytic expressions of the power spectrum, spectral tilt and non-Gaussianity for the separable potentials of two inflaton scalars, and apply them to some specific models.