Dynamics of a homogeneous and isotropic space in pure cubic f(R) gravity

TL;DR

This paper investigates the dynamics of homogeneous and isotropic space in cubic f(R) gravity without matter, proposing a method to constrain model parameters based on space evolution, stability, and inflationary divergence.

Contribution

It introduces a new method for analyzing f(R) gravity models by examining metric dynamics to limit model parameters in a matter-free FLRW universe.

Findings

Parameters can be constrained by space growth behavior

Instability and divergence help limit model parameters

Method applicable to simple cubic f(R) gravity models

Abstract

We consider a possible ways of the dynamics of a homogeneous and isotropic space described by the FLRW metric in the framework of cubic f(R) gravity in the absence of matter. This article points an method for limiting the parameters of extended gravity models. We propose and develop a method for f(R) gravity models based on the dynamics of metrics for various model parameters in the simplest example. The influence of parameters and initial conditions on further dynamics are discussed. The parameters can be limited by 1) slow growth of space, 2) instability, 3) divergence with the inflationary scenario.