Non-linear corrections to inflationary power spectrum

TL;DR

This paper demonstrates that during slow-roll inflation, non-linear corrections to the curvature perturbation power spectrum are negligible on large scales, validating the use of linear theory for such analyses.

Contribution

It provides a detailed analysis showing the dominance of linear contributions and the insignificance of non-linear corrections in the inflationary power spectrum.

Findings

Linear power spectrum dominates on large scales

Non-linear corrections are negligible during slow-roll inflation

Linear perturbation theory is sufficient for studying inflationary spectra

Abstract

We study non-linear contributions to the power spectrum of the curvature perturbation on super-horizon scales, produced during slow-roll inflation driven by a canonical single scalar field. We find that on large scales the linear power spectrum completely dominates and leading non-linear corrections remain totally negligible, indicating that we can safely rely on linear perturbation theory to study inflationary power spectrum. We also briefly comment on the infrared and ultraviolet behaviour of the non-linear corrections.