Non-minimally coupled quintessential inflation

TL;DR

This paper introduces a unified scalar field model with non-minimal coupling that explains both early cosmic inflation and late-time acceleration, matching current observational data and predicting potential signatures of dark energy deviations.

Contribution

It proposes a novel single-field framework with exponential coupling and dual-plateau potential that naturally transitions from inflation to dark energy behavior.

Findings

Predicted spectral index ($n_s$) and tensor-to-scalar ratio ($r$) align with observations.

Model yields a dark energy equation of state ($w_$) close to -1 with measurable deviations.

Demonstrates a unified approach to early and late cosmic acceleration within one scalar field theory.

Abstract

We present a unified framework that simultaneously addresses the dynamics of early-time cosmic inflation and late-time cosmic acceleration within the context of a single scalar field non-minimally coupled to gravity. By employing an exponential coupling function and a scalar potential with dual asymptotic plateaus, our model naturally transitions from inflationary dynamics at small field values to a quintessence-like behavior at large field values. We derive the inflationary predictions for the spectral index ($n_s$) and tensor-to-scalar ratio ($r$) in agreement with current observational constraints. For late-time acceleration, the model produces a viable dark energy component with an equation of state $w_\phi$ approaching $-1$ but retaining a measurable deviation that could serve as an observational signature. This work demonstrates that a single theoretical framework can reconcile both early inflation and the late-time accelerated expansion of the Universe.