Minimal extension of General Relativity: alternative gravity model with non-minimal coupling between matter and curvature

TL;DR

This paper explores a minimal extension of General Relativity involving a non-minimal matter-curvature coupling, analyzing its implications for astrophysics, cosmology, and potential explanations for dark matter and dark energy phenomena.

Contribution

It introduces and discusses the effects of a non-minimal coupling between matter and curvature, including its impact on cosmological acceleration and galactic dynamics, and links it to multi-scalar theories.

Findings

Non-minimal coupling affects the choice of Lagrangian density.

Potential to mimic dark matter in galaxies and clusters.

Possible explanation for the Universe's accelerated expansion.

Abstract

We examine an extension of General Relativity with an explicit non-minimal coupling between matter and curvature. The purpose of this work is to present an overview of the implications of the latter to various contexts, ranging from astrophysical matter distributions to a cosmological setting. Various results are discussed, including the impact of this non-minimal coupling on the choice of Lagrangian density, on a mechanism to mimic galactic and cluster dark matter, on the possibility of accounting for the accelerated expansion of the Universe, energy density fluctuations and modifications to post-inflationary reheating. The equivalence between a model exhibiting a non-minimal coupling and multi-scalar-theories is also discussed.