Dark energy in modified Gauss-Bonnet gravity: late-time acceleration and the hierarchy problem

TL;DR

This paper explores a modified Gauss-Bonnet gravity model that can naturally produce late-time cosmic acceleration, aligns with Solar System tests, and potentially addresses the hierarchy problem through its rich cosmological solutions.

Contribution

It demonstrates the viability of $f(G)$ gravity models in explaining cosmic acceleration and investigates their properties, including solutions, entropy, and quantum aspects, with implications for the hierarchy problem.

Findings

The model can produce effective cosmological constant, quintessence, or phantom acceleration.

It is compatible with Solar System constraints.

The paper discusses solutions, entropy, and quantum properties of $f(G)$ gravity in de Sitter space.

Abstract

Dark energy cosmology is considered in a modified Gauss-Bonnet (GB) model of gravity where an arbitrary function of the GB invariant, $f(G)$, is added to the General Relativity action. We show that such theory is endowed with a quite rich cosmological structure: it may naturally lead to an effective cosmological constant, quintessence or phantom cosmic acceleration, with a possible transition from deceleration to acceleration. It is demonstrated in the paper that this theory is perfectly viable, since it is compliant with Solar System constraints. Specific properties of $f(G)$ gravity in a de Sitter universe, such as dS and SdS solutions, their entropy and its explicit one-loop quantization are studied. The issue of a possible solution of the hierarchy problem in modified gravities is addressed too.