One-loop graviton corrections to the curvature perturbation from inflation

TL;DR

This paper calculates one-loop quantum corrections from gravitons to the curvature perturbation in single-field slow-roll inflation, highlighting their significance alongside scalar interactions for accurate cosmological predictions.

Contribution

It provides the first detailed computation of graviton-induced one-loop corrections to the inflationary power spectrum, emphasizing their comparable magnitude to scalar self-interactions.

Findings

Graviton corrections are of the same order as scalar self-interactions.

One-loop corrections significantly impact the curvature perturbation spectrum.

Tensor mode corrections cannot be neglected in precise inflationary models.

Abstract

We compute one-loop corrections to the power spectrum of the curvature perturbation in single-field slow-roll inflation arising from gravitons and inflaton interactions. The quantum corrections due to gravitons to the power spectrum of the inflaton field are computed around the time of horizon crossing and their effect on the curvature perturbation is obtained on superhorizon scales through the delta-N formalism. We point out that one-loop corrections from the tensor modes are of the same magnitude as those coming from scalar self-interactions, therefore they cannot be neglected in a self-consistent calculation.