# Study of warm inflationary models and their parameter estimation from CMB

## TL;DR

This paper investigates warm inflation models with monomial potentials, estimating their parameters using CMB data, and finds that certain models are consistent with observational constraints, supporting their viability.

## Contribution

The study performs a detailed parameter estimation of warm inflation models with $\lambda\phi^4$ and $\lambda\phi^6$ potentials using MCMC analysis on CMB data, demonstrating their compatibility with observations.

## Key findings

- Estimated model parameters consistent with observational bounds.
- Warm inflation models can produce viable $n_s$ and $r$ values.
- Parameter distributions provide insights for inflationary model building.

## Abstract

Observations of the temperature anisotropies in the Cosmic Microwave Background (CMB) radiation show that the models of inflation with the monomial potentials are inconsistent with the allowed $n_s-r$ bounds. However certain monomial potentials of inflation are allowed in the context of \textit{Warm Inflation}, where the inflaton's coupling with other fields are significant both \textit{during and after} the inflationary phase. In our study, we consider $\lambda\phi^4$ and $\lambda\phi^6$ models of warm inflation with different forms of the inflaton dissipation coefficient. We parameterize the primordial power spectrum in terms of the model parameters, namely, the inflaton self coupling, $\lambda$, and the dissipation parameter, $Q_P$, due to inflaton's interaction with the other fields. Then we obtain the joint and marginal distributions of these parameters by carrying out a Markov Chain Monte Carlo (MCMC) analysis using the {\tt CosmoMC} numerical code. An estimation of these physical parameters is essential for model building. We also obtain the $n_s$ and $r$ values for the mean values of the parameters and find them to be consistent with the observational bounds, confirming that these simple models are viable models for describing inflation.