Modelling Quintessential Inflation in Palatini Modified Gravity

TL;DR

This paper presents a model of quintessential inflation within Palatini modified gravity, using a non-minimally coupled scalar field with an exponential potential, achieving successful inflation without fine-tuning and making testable dark energy predictions.

Contribution

It introduces a novel quintessential inflation model in Palatini $R^2$ gravity with a non-minimal scalar field, avoiding fine-tuning and providing observable predictions.

Findings

Successful inflation without fine-tuning of parameters

Predictions for dark energy characteristics testable by future observations

Insights into the non-minimal coupling and its running in modified gravity

Abstract

We study a model of quintessential inflation constructed in $R^2$ modified gravity with a non-minimally coupled scalar field, in the Palatini formalism. Our non-minimal inflaton field is characterised by a simple exponential potential. We find that successful quintessential inflation can be achieved with no fine-tuning on the model parameters. Predictions on the characteristics of dark energy will be tested by observations in the near future, while contrast with existing observations provides insights on the modified gravity background, such as the value of the non-minimal coupling and its running.