Perturbations of the metric induced by back - reaction in the warm inflation scenario

TL;DR

This paper investigates how quantum fluctuations in matter fields during warm inflation lead to metric perturbations and curvature effects, using a second-order expansion and semiclassical methods to analyze the power spectrum.

Contribution

It introduces a second-order quantum fluctuation expansion in warm inflation and links matter fluctuations to metric and curvature perturbations.

Findings

Metric fluctuations are generated by matter field fluctuations.

The power spectrum of metric fluctuations is computed in the infrared sector.

Effective curvature terms arise from metric perturbations.

Abstract

A second-order expansion for the quantum fluctuations of the matter field was considered in the framemork of the warm inflation scenario. The friction and Hubble parameters were expanded by means of a semiclassical approach. The fluctuations of the Hubble parameter generates fluctuations of the metric. These metric fluctuations produce an effective term of curvature. The power spectrum for the metric fluctuations can be calculated on the infrared sector.