Embedding Warm Natural Inflation in $f(\phi)T$ gravity

Abstract

We study warm inflation in the framework of $f(\phi)T$ gravity, where $\phi$ is the inflaton and $T$ is the trace of the energy-momentum tensor. The inflaton field is assumed to roll on the natural potential and the result is analyzed in light of Planck 2018 and BICEP/Keck 2021 data. We start our work by obtaining the field equations under slow-roll approximations. We then evaluate the scalar and tensor power spectra and their corresponding spectral index and tensor-to-scalar ratio with a temperature-dependent form of the dissipation coefficient during the inflationary era. We find that the warm inflation model in $f(\phi)T$ gravity is compatible with observational bands.