Modified f(G) gravity models with curvature-matter coupling

TL;DR

This paper introduces a modified f(G) gravity model with curvature-matter coupling, analyzing its field equations, energy conditions, stability, and implications for cosmic acceleration, highlighting deviations from general relativity.

Contribution

It proposes a new f(G) gravity model with matter-geometry coupling, deriving its field equations, energy conditions, and exploring its potential for explaining cosmic acceleration.

Findings

Energy-momentum tensor non-conservation and extra-force presence.

Derived energy conditions and stability criteria at de Sitter point.

Constraints on specific models and conditions for late-time acceleration.

Abstract

A modified f(G) gravity model with coupling between matter and geometry is proposed, which is described by the product of the Lagrange density of the matter and an arbitrary function of the Gauss-Bonnet term. The field equations and the equations of motion corresponding to this model show the non-conservation of the energy-momentum tensor, the presence of an extra-force acting on test particles and the non-geodesic motion. Moreover, the energy conditions and the stability criterion at de Sitter point in the modified f(G) gravity models with curvature-matter coupling are derived, which can degenerate to the well-known energy conditions in general relativity. Furthermore, in order to get some insight on the meaning of these energy conditions, we apply them to the specific models of f(G) gravity and the corresponding constraints on the models are given. In addition, the conditions and the candidate for late-time cosmic accelerated expansion in the modified f(G) gravity are studied by means of conditions of power-law expansion and the equation of state of matter less than -1/ 3 .