Energy Conditions in Gauss-Bonnet Gravity

TL;DR

This paper investigates energy conditions in modified Gauss-Bonnet gravity, constrains models using cosmography, and explores their potential to describe early inflation and cosmic evolution.

Contribution

It introduces specific $f(G)$ models with symmetries, analyzing conditions for energy condition violations and slow-roll parameters in the context of cosmic history.

Findings

Certain $f(G)$ models can violate energy conditions.

Models can produce small slow-roll parameters for inflation.

The theory can potentially describe both early and late cosmic evolution.

Abstract

We study the Energy Conditions in modified $f(G)$ gravity, with $G$ being the topological Gauss-Bonnet term. Then we use the cosmographic parameters to constrain the functional form of the gravitational action and investigate the possibility to have standard inflation in the early time. Specifically, we select models containing symmetries within the modified $f(\G)$ theory and obtain conditions for which i) the energy conditions can be violated and ii) the magnitude of the slow-roll parameters is small, thus suggesting that under given limits the analyzed theory can potentially trace the cosmic history both at early and at the late times.