Spectrum of Curvature Perturbation of Multi-field Inflation with Small-Field Potential

TL;DR

This paper analyzes the spectrum of curvature perturbations in multi-field small-field inflation, showing it can be either redder or bluer than single-field cases depending on field values and masses.

Contribution

It extends the understanding of curvature perturbation spectra in multi-field inflation with small-field potentials using the Sasaki-Stewart formalism.

Findings

Spectrum can be redder or bluer than single-field inflation.

Dependence of spectrum shape on field values and effective masses.

Neglects isocurvature perturbations in analysis.

Abstract

In this paper, we have studied the spectrum of curvature perturbation of multi-field inflation with general small-field potential. We assume that the isocurvature perturbation may be neglected, and by using the Sasaki-Stewart formalism, we found that the spectrum may be redder or bluer than of its corresponding single field. The result depends upon the values of fields and their effective masses at the horizon-crossing time. We discuss the relevant cases.