Entropy mode loops and cosmological correlations during perturbative reheating

TL;DR

This paper investigates the impact of entropy mode loops on cosmological correlations during perturbative reheating, revealing that while smaller than preheating effects, they surpass inflationary loop contributions, depending on key model parameters.

Contribution

It extends the analysis of entropy mode loop effects from preheating to perturbative reheating, quantifying their dependence on model parameters and their relative magnitude.

Findings

Loop corrections depend on inflaton amplitude, decay rate, and mass.

Loop effects during reheating are larger than during inflation.

Loop contributions are smaller than in preheating but still significant.

Abstract

Recently, it has been shown that during preheating the entropy modes circulating in the loops, which correspond to the inflaton decay products, meaningfully modify the cosmological correlation functions at superhorizon scales. In this paper, we determine the significance of the same effect when reheating occurs in the perturbative regime. In a typical two scalar field model, the magnitude of the loop corrections are shown to depend on several parameters like the background inflaton amplitude in the beginning of reheating, the inflaton decay rate and the inflaton mass. Although the loop contributions turn out to be small as compared to the preheating case, they still come out larger than the loop effects during inflation.