LambdaCDM epoch reconstruction from F(R,G) and modified Gauss-Bonnet gravities

TL;DR

This paper explores modified Gauss-Bonnet and scalar-Gauss-Bonnet gravity theories, demonstrating their ability to replicate LambdaCDM cosmology and produce various cosmic acceleration behaviors without a cosmological constant.

Contribution

It introduces and analyzes generalized Gauss-Bonnet gravity models that can naturally reproduce the LambdaCDM era and diverse acceleration phases without a cosmological constant.

Findings

Models can produce effective cosmological constants

Theories describe transition from deceleration to acceleration

Viability of modified gravity as cosmological models

Abstract

Dark energy cosmology is considered in a modified Gauss-Bonnet model of gravity with and without a scalar field. It is shown that these generalizations of General Relativity endow it with a very rich cosmological structure: it may naturally lead to an effective cosmological constant, quintessence or phantom cosmic acceleration, with the possibility to describe the transition from a decelerating to an accelerating phase explicitly. It is demonstrated here that these modified GB and scalar-GB theories are perfectly viable as cosmological models. They can describe the LambdaCDM cosmological era without any need for a cosmological constant. Specific properties of these theories of gravity in different particular cases, such as the de Sitter one, are studied.