Cosmological evolutions in Tsujikawa model of $f(R)$ Gravity

TL;DR

This paper investigates the cosmological implications of the Tsujikawa $f(R)$ gravity model, analyzing its background evolution and perturbations, and constraining its parameters using current observational data.

Contribution

It provides the first detailed constraints on the Tsujikawa $f(R)$ model parameters using observational data and compares its cosmological behavior with the standard $ ext{Lambda CDM}$ model.

Findings

Matter density fluctuation is suppressed in the TM.

Constraint on neutrino mass sum is relaxed in the TM.

Deceleration and dark energy equation of state parameters are compared with $ ext{Lambda CDM}$.

Abstract

We concentrate on the cosmological properties in the Tsujikawa model (TM) of viable $f(R)$ gravity with the dynamical background evolution and linear perturbation theory by using the CosmoMC package. We study the constraints of the cosmological variables along with the model parameter from the current observational data. In particular, we show that the matter density fluctuation is suppressed and the constraint of the neutrino mass sum is relaxed in the TM, which are similar to other viable $f(R)$ models. In addition, we discuss the parameters of the deceleration and equation of state for dark energy in the TM and compare them with those in the $\Lambda$CDM model.