Reheating and Inflationary dynamics driven by an inverse tangent potential

TL;DR

This paper explores inflation and reheating in the early universe using an inverse tangent potential, deriving key parameters, constraining them with observational data, and showing it as a viable alternative to standard models.

Contribution

It introduces and analyzes an inverse tangent potential for inflation, deriving observable predictions and constraining parameters with recent cosmological data.

Findings

The inverse tangent potential fits Planck-2018 and ACT data within constraints.

Bounds on reheating temperature and e-folds are established.

It can serve as an alternative to excluded standard inflationary models.

Abstract

In this work, we study the early universe inflation and the post-inflation reheating era employing an inverse tangent potential of the form $V=V_0 \cdot[tan^{-1}(\frac{\kappa \phi}{m_p})]^2$, where $\kappa$ is a free parameter of the potential and $m_p$ is the reduced Planck mass. We derive the slow roll parameters, the number of e-folds(N), the scalar spectral index $n_s$, the tensor-to-scalar ratio $r$, and the tensor spectral index $n_T$ for the inverse tangent potential. We examine the inflationary observables using the data of the Planck-2018 and recent ACT collaboration and obtain constraints on the potential parameter $\kappa$. We also employ a reheating analysis by invoking the conservation of entropy between today and the time when reheating starts. We obtain bounds on the reheating temperature $T_{re}$ and the number of e-folds of the reheating $N_{re}$ using the spectral-index $n_s$ constraints from Planck 2018 and the ACT results. We show that this inverse-tangent potential can act as an alternative to the standard inflationary potentials like Starobinsky which are excluded at $2\sigma$ level by the recent sixth data release (DR6) of the Atacama Cosmology Telescope (ACT) collaboration.