Impact of curvature based geometric constraints on $F(R)$ theory

TL;DR

This paper explores how curvature-based geometric constraints influence $F(R)$ gravity theories, classifies specific spacetimes, derives modified Friedmann equations, and tests models against observational data.

Contribution

It introduces a novel classification of curvature-constrained spacetimes and applies these results to analyze $F(R)$ gravity models with observational constraints.

Findings

Classified spacetimes with non-null associated vectors under curvature constraints.

Derived and analyzed modified Friedmann equations in a model-independent framework.

Examined specific $F(R)$ models against observational data on deceleration, jerk, and Hubble parameters.

Abstract

Theories of gravity are fundamentally a relation between matter and the geometric structure of the underlying spacetime. So once we put some additional restrictions on the spacetime geometry, the theory of gravity is bound to get the impact, irrespective of whether it is general relativity or the modified theories of gravity. In the present article, we consider two curvature-based constraints, namely the almost pseudo-Ricci symmetric and weakly Ricci symmetric condition. As a novel result, such spacetimes with non-null associated vectors are entirely classified, and then applying the obtained results, we investigate these spacetimes as solutions of the $F(R)$-gravity theory. The modified Friedmann equations are derived and analysed in a model-independent way first. Finally, two $F(R)$ gravity models are examined for recent observational constrained values of the deceleration, jerk, and Hubble parameters. We further discuss the behavior of energy conditions.