The $\alpha$-Attractor E-Model in Warm Inflation: Observational Viability from Planck 2018

TL;DR

This paper investigates the warm inflationary dynamics of the $oldsymbol{ ext{alpha}}$-attractor E-model, demonstrating its compatibility with Planck 2018 data across different dissipative regimes and highlighting the role of dissipation in observational viability.

Contribution

It provides an analytical study of the $oldsymbol{ ext{alpha}}$-attractor E-model in warm inflation, incorporating different dissipation functions and comparing predictions with observational data.

Findings

Warm $oldsymbol{ ext{alpha}}$-attractor E-models are compatible with Planck 2018 data.

Dissipation influences inflationary predictions and expands viable parameter space.

Both weak and strong dissipative regimes yield observationally consistent results.

Abstract

We explore the inflationary evolution and observational viability of the $\alpha$-attractor E-model in the framework of warm inflation, focusing on both weak and strong dissipative regimes, with a dissipation coefficient linear in temperature. In the strong regime, we account for the growth of inflaton fluctuations due to coupling with the radiation bath via two different forms for the dissipation enhancement function: one associated with plateau-like potentials, and another motivated by the warm little inflation scenario. Employing slow roll conditions, we analytically derive the expressions for the key inflationary observables, the spectral index $n_s$ and the tensor-to-scalar ratio $r$, in both dissipative regimes. The resulting theoretical trajectories on the $n_s$--$r$ plane are then juxtaposed with the contour plots obtained from Planck 2018 data in order to constrain the model parameter. Our analysis shows that the warm $\alpha$-attractor E-model remains compatible with observations in both dissipative regimes, with dissipation playing a crucial role in shifting the predictions and enlarging the viable parameter space, highlighting observational robustness of the model when extended to warm inflation.