On preheating after inflation in general scalar-tensor theories of gravity

TL;DR

This paper explores the preheating process after inflation within general scalar-tensor gravity theories, analyzing particle production via parametric resonances in two specific models and demonstrating their broad resonance potential.

Contribution

It introduces a detailed analysis of preheating in scalar-tensor theories with exponential and hyperbolic tangent potentials, highlighting the broad parametric resonance phenomena.

Findings

Parametric resonances can be described by the Mathieu equation in Minkowski space.

Resonances are sufficiently broad for exponential particle growth.

Preheating dynamics depend on the specific potential forms studied.

Abstract

In this work, we investigate the preheating mechanism after inflation in general scalar-tensor theories of gravity. In the present scenario, we consider two-field scenario and then derive the potential of exponential and hyperbolic tangent forms. We study the evolution of the background system when the back reaction on the background field is neglected. We examine the particle production due to parametric resonances in both models. We find that in Minkowski space the stage of parametric resonances can be described by the Mathieu equation. Finally, we demonstrate that parametric resonances in our models are sufficiently broad possible for the exponential growth of the number of particles.