Warm inflation in general scalar-tensor theory of gravity

TL;DR

This paper explores warm inflation within a general scalar-tensor gravity framework, deriving specific potentials, analyzing strong dissipation regimes, and constraining model parameters using Planck 2018 data to ensure observational consistency.

Contribution

It introduces a novel analysis of warm inflation in scalar-tensor theories with exponential and hyperbolic tangent potentials, focusing on strong dissipation and observational constraints.

Findings

Weak coupling limit $\xi \\ll 1$ is necessary for compatibility with Planck data.

Constraints on the potential scale $V_0$ are established.

Inflationary observables are computed and matched with observations.

Abstract

In this work, we investigate warm inflationary models in the context of a general scalar-tensor theory of gravity which is coupled to radiation through a dissipation term. We first derive the potential of exponential and hyperbolic tangent forms. We consider a dissipation parameter of the form $\Gamma = C_{1}T$ with $C_1$ being a coupling parameter and focus only on the strong regime of which the interaction between inflaton and radiation fluid has been taken into account. We compute inflationary observables and constrain the parameters of our model using current Planck 2018 data. From our analysis, we discover that the weak coupling limit $\xi\ll 1$ is needed in order to have the derived $n_s$ and $r$ consistent with the Planck 2018 observational constraints. Particularly, we constrain the potential scale $V_{0}$ of the models.