# Constraining chameleon field driven warm inflation with Planck 2018 data

## TL;DR

This paper explores a warm inflation model driven by chameleon scalar fields with non-minimal coupling, testing its predictions against Planck 2018 data and finding consistency with observations.

## Contribution

It introduces a chameleon field-based warm inflation model with non-conserved energy-momentum, and compares its predictions to Planck 2018 data for the first time.

## Key findings

- Model predictions align with Planck 2018 constraints.
- Perturbation parameters are derived for weak and strong dissipative regimes.
- The scenario remains consistent with observational data.

## Abstract

We investigate warm inflationary scenario in which the accelerated expansion of the early Universe is driven by chameleon-like scalar fields. Due to the non-minimal coupling between the scalar field and the matter sector, the energy-momentum tensor of each fluid component is not conserved anymore, and the generalized balance equation is obtained. The new source term in the energy equation can be used to model warm inflation. On the other hand, if the coupling function varies slowly, the model reduces to the standard model used for the description of cold inflation. To test the validity of the warm chameleon inflation model, the results for warm inflationary scenarios are compared with the observational Planck2018 Cosmic Microwave Background data. In this regard, the perturbation parameters such as the amplitude of scalar perturbations, the scalar spectral index and the tensor-to-scalar ratio are derived at the horizon crossing in two approximations, corresponding to the weak and strong dissipative regimes. As a general result it turns out that the theoretical predictions of the chameleon warm inflationary scenario are consistent with the Planck 2018 observations.