Quintessential Inflation in Logarithmic Cartan $F(R)$ Gravity

TL;DR

This paper explores how a small logarithmic modification to general relativity within $F(R)$ gravity can account for both early universe inflation and current dark energy-driven acceleration, aligning with observations.

Contribution

It introduces a specific logarithmic $F(R)$ gravity model that unifies inflation and dark energy, with parameters fixed to match cosmological scales and observations.

Findings

CMB fluctuations consistent with observations

Reheating temperature suitable for nucleosynthesis

Scalaron field drives current acceleration

Abstract

We investigate the quintessential inflation in the logarithmic Cartan $F(R)$ gravity. A small logarithmic modification of the general relativity has the potential to introduce both inflation and dark energy. We evaluate the time evolution of the Universe such as inflation, reheating, and dark energy. The parameters in the model are fixed to introduce the inflation and the dark energy scales. We show that the CMB fluctuations induced by the inflation are consistent with the current observations. In the reheating process, it is possible to achieve the reheating temperature required for nucleosynthesis in Big Bang scenario. It can be seen that by choosing an appropriate value for the scalaron field after reheating, the scalaron field again dominates the energy of the Universe and causes the current accelerating expansion as dark energy.