Reheating in Models with Non-minimal Coupling in metric and Palatini formalisms

TL;DR

This paper analyzes the reheating process in inflationary models with non-minimal coupling between the inflaton and gravity, providing analytic expressions for observables across different coupling regimes and formalisms.

Contribution

It introduces a unified framework for calculating cosmological observables and reheating temperatures in models with non-minimal coupling in both metric and Palatini formalisms.

Findings

Analytic expressions for cosmological observables in non-minimal coupling models.

Predictions for reheating temperature across a range of coupling parameters.

Comparison of metric and Palatini formalisms in inflationary reheating.

Abstract

We study reheating of inflationary models with general non-minimal coupling $K(\phi)R$ with $K(\phi)\sim \sqrt{V(\phi)}$ where $R$ is the Ricci scalar and $V$ is the inflaton potential. In particular, when we take the monomial potential $K(\phi) \propto \phi^m$ with $m \in \mathbb{Z}_+$, we provide general analytic expressions for cosmological observables. We consider a wide range of non-minimal coupling $ \xi \in [0, \infty) $ in metric and Palatini formalisms and derive the predictions for cosmological observables and the reheating temperature taking a general equation of state parameter $ w_\text{reh} $.