Viscous Fluids and Gauss-Bonnet Modified Gravity

TL;DR

This paper explores how cosmic fluids, including viscous effects and quantum corrections, influence finite-time singularities in modified $f(R,G)$-gravity, analyzing conditions for their avoidance in different dark energy regimes.

Contribution

It introduces a comprehensive analysis of cosmic fluid effects, including viscosity and quantum effects, on singularities within $f(R,G)$-gravity, extending previous models.

Findings

Viscous fluids can alter singularity behavior.

Quantum effects may prevent certain singularities.

Different dark energy regimes affect singularity outcomes.

Abstract

We study effects of cosmic fluids on finite-time future singularities in modified $f(R,G)$-gravity, where $R$ and $G$ are the Ricci scalar and the Gauss-Bonnet invariant, respectively. We consider the fluid equation of state in the general form, $\omega=\omega(\rho)$, and we suppose the existence of a bulk viscosity. We investigate quintessence region ($\omega>-1$) and phantom region ($\omega<-1$) and the possibility to change or avoid the singularities in $f(R,G)$-gravity. Finally, we study the inclusion of quantum effects in large curvatures regime.