Evolution of Large Scale Curvature Fluctuations During the Perturbative Decay of the Inflaton

TL;DR

This paper investigates how large-scale curvature fluctuations evolve during and after inflation when a scalar field interacts with a perfect fluid, revealing potential changes in observable cosmological perturbations during inflaton decay.

Contribution

It introduces a model of inflation with a coupled scalar field and perfect fluid, analyzing the evolution of curvature fluctuations through decay processes.

Findings

Large-scale curvature fluctuations can change during inflaton decay.

Isocurvature perturbations are generated during slow-roll inflation.

Post-inflation decay affects observable cosmological fluctuations.

Abstract

We study the evolution of cosmological fluctuations during and after inflation driven by a scalar field coupled to a perfect fluid through afriction term. During the slow-roll regime for the scalar field, the perfect fluid is also frozen and isocurvature perturbations are generated. After the end of inflation, during the decay of the inflaton, we find that a change in the observationally relevant large scale curvature fluctuations is possible.