Non-minimal curvature-matter couplings in modified gravity

TL;DR

This paper explores the effects of non-minimal curvature-matter couplings in f(R) gravity, highlighting how such couplings lead to non-conservation of energy-momentum and result in extra forces affecting particle motion.

Contribution

It analyzes the implications of curvature-matter couplings in modified gravity theories, emphasizing their impact on energy-momentum conservation and particle trajectories.

Findings

Curvature-matter coupling induces non-zero covariant derivative of energy-momentum.

Non-geodesic motion arises due to the extra force from the coupling.

The study suggests new directions for research in modified gravity theories.

Abstract

Recently, in the context of f(R) modified theories of gravity, it was shown that a curvature-matter coupling induces a non-vanishing covariant derivative of the energy-momentum, implying non-geodesic motion and, under appropriate conditions, leading to the appearance of an extra force. We study the implications of this proposal and discuss some directions for future research.