Modified gravity as an alternative for Lambda-CDM cosmology

TL;DR

This paper develops reconstruction schemes for modified $f(R)$ gravity models that can replicate the entire cosmic history, offering an alternative to Lambda-CDM with different late-time behaviors.

Contribution

It introduces two $f(R)$ gravity models capable of reproducing the universe's evolution, including radiation, matter, and acceleration phases, as alternatives to standard Lambda-CDM.

Findings

First model matches radiation and matter domination with late-time acceleration.

Second model approaches General Relativity without singularity.

Both models align with observed cosmic evolution.

Abstract

The reconstruction scheme is developed for modified $f(R)$ gravity with realistic matter (dark matter, baryons, radiation). Two versions of such theory are constructed: the first one describes the sequence of radiation and matter domination, decceleration-acceleration transition and acceleration era and the second one is reconstructed from exact Lambda-CDM cosmology. The asymptotic behaviour of first model at late times coincides with the theory containing positive and negative powers of curvature while second model approaches to General Relativity without singularity at zero curvature.