# Observational constraints on successful model of quintessential Inflation

## TL;DR

This paper investigates a generalized exponential potential model for quintessential inflation, analyzing its inflationary predictions, late-time acceleration, and neutrino mass implications in light of observational data.

## Contribution

It introduces a novel generalized exponential potential for quintessential inflation and provides detailed observational constraints, including neutrino mass effects and compatibility with Planck data.

## Key findings

- The model fits Planck 2015 data with specific spectral index and tensor-to-scalar ratio.
- Neutrino masses up to ~2.5 eV are compatible with the model.
- The potential allows for late-time acceleration consistent with observations.

## Abstract

We study quintessential inflation using a generalized exponential potential $V(\phi)\propto exp(-\lambda \phi^n/Mpl^n), n>1$, the model admits slow-roll inflation at early times and leads to close-to-scaling behaviour in the post inflationary era with an exit to dark energy at late times. We present detailed investigations of the inflationary stage in the light of the Planck 2015 results, study post-inflationary dynamics and analytically confirm the existence of an approximately scaling solution. Additionally, assuming that standard massive neutrinos are non-minimally coupled, makes the field $\phi$ dominant once again at late times giving rise to present accelerated expansion of the Universe. We derive observational constraints on the field and time-dependent neutrino masses. In particular, for $n=6 (8)$, the parameter $\lambda$ is constrained to be,$\log \lambda > -7.29 (-11.7)$; the model produces the spectral index of the power spectrum of primordial scalar (matter density) perturbations as $ n_s = 0.959 \pm 0.001 (0.961 \pm 0.001)$ and tiny tensor-to-scalar ratio, $r<1.72 \times 10^{-2} (2.32 \times 10^{-2})$ respectively. Consequently, the upper bound on possible values of the sum of neutrino masses $\Sigma m_{\nu} \lesssim 2.5$ eV significantly enhances compared to that in the standard $\Lambda$CDM model.