Study of the preheating phase of chaotic inflation

TL;DR

This paper numerically investigates the preheating phase in chaotic inflation, focusing on particle production, inflaton damping, and validating previous predictions with new detailed solutions.

Contribution

First numerical solutions of the coupled equations during preheating in chaotic inflation, including backreaction effects, with analysis of mode amplification and inflaton damping.

Findings

Validated previous predictions of preheating dynamics.

Identified and resolved issues related to parametric amplification.

Provided new insights into inflaton damping mechanisms.

Abstract

Particle production and its effects on the inflaton field are investigated during the preheating phase of chaotic inflation using a model consisting of a massive scalar inflaton field coupled to N massless quantum scalar fields. The effects of spacetime curvature and interactions between the quantum fields are ignored. A large N expansion is used to obtain a coupled set of equations including a backreaction equation for the classical inflaton field. Previous studies of preheating using these equations have been done. Here the first numerical solutions to the full set of equations are obtained for various values of the coupling constant and the initial amplitude of the inflaton field. States are chosen so that initially the backreaction effects on the inflaton field are small and the mode equations for the quantum fields take the form of Mathieu equations. Potential problems relating to the parametric amplification of certain modes of the quantum fields are identified and resolved. A detailed study of the damping of the inflaton field is undertaken. Some predictions of previous studies are verified and some new results are obtained.