One-loop Corrections to Scalar and Tensor Perturbations during Inflation in Stochastic Gravity

TL;DR

This paper investigates one-loop quantum corrections to scalar and tensor perturbations during inflation using stochastic gravity, revealing IR divergence in scalars but not in tensors, with corrections amplified by e-foldings.

Contribution

It introduces a method to regularize IR divergences in scalar perturbations and compares the behavior of scalar and tensor corrections during inflation.

Findings

Loop corrections to scalar perturbations are IR divergent and amplified by e-foldings.

Tensor perturbations do not exhibit IR divergence.

Logarithmic corrections appear in scalar perturbations as discussed by previous studies.

Abstract

Based on the stochastic gravity, we study the loop corrections to the scalar and tensor perturbations during inflation. Since the loop corrections to scalar perturbations suffer infrared (IR) divergence, we consider the IR regularization to obtain the finite value. We find that the loop corrections to the scalar perturbations are amplified by the e-folding; in other words there appear the logarithmic correction, just as discussed by M.Sloth et al. On the other hand, we find that the tensor perturbations do not suffer from infrared divergence.