Cosmology of $f(R, \Box R)$ gravity

TL;DR

This paper uses dynamical system analysis to study high-order $f(R, ox R)$ gravity theories, showing that higher-order terms significantly influence cosmological evolution and can prevent finite-time singularities.

Contribution

It extends previous work by analyzing the cosmology of up to eighth-order $f(R, ox R)$ theories and highlights the impact of higher-order terms on avoiding singularities.

Findings

Higher-order terms influence cosmological dynamics

They can prevent finite-time singularities

The phase space analysis reveals new stability features

Abstract

Using dynamical system analysis, we explore the cosmology of theories of order up to eight order of the form $f(R, \Box R)$. The phase space of these cosmology reveals that higher-order terms can have a dramatic influence on the evolution of the cosmology, avoiding the onset of finite time singularities. We also confirm and extend some of results which were obtained in the past for this class of theories.