A Deep Dive into f(R) Gravity Theory

TL;DR

This paper explores f(R) gravity theory, deriving the deceleration parameter's behavior over redshift, showing it can explain both early inflation and late-time acceleration without dark energy or dark matter.

Contribution

It introduces a Taylor expansion approach to f(R) gravity that models the entire cosmic history from inflation to acceleration.

Findings

Two leading terms in Taylor expansion explain late-time acceleration.

Higher-order terms describe early Universe inflation.

f(R) gravity can unify cosmic evolution phases.

Abstract

In this paper we have derived the behavior of deceleration parameter with respect to redshift in context of f(R) gravity in vacuum using Taylor expansion of derivative of action. Here we have obtained that the two first terms in Taylor expansion may describe the late time acceleration which is appeared by SNeIa without need of dark energy and dark matter. Also we have derived that any other terms higher than z in Taylor expansion may describe main inflationary epoch in the early Universe. We have shown that f(R) gravity may cover all the dynamical history of the Universe from the beginning to the late time accelerating phase transition.