The cosmic jerk parameter in f(R) gravity

TL;DR

This paper derives the cosmic jerk parameter within f(R) gravity using the Palatini approach, comparing theoretical predictions with observational data to assess model viability.

Contribution

It provides a new derivation of the jerk parameter in f(R) gravity using the Palatini formalism and tests specific models against observational data.

Findings

The model with f(R)=R-α^2/(3R) matches SNLS SNIa and galaxy cluster data.

The same model does not fit the SNIa gold sample data.

The derivation uses the Einstein conformal gauge and Palatini variational principle.

Abstract

We derive the expression for the jerk parameter in $f(R)$ gravity. We use the Palatini variational principle and the field equations in the Einstein conformal gauge. For the particular case $f(R)=R-\frac{\alpha^2}{3R}$, the predicted value of the jerk parameter agrees with the SNLS SNIa and X-ray galaxy cluster distance data but does not with the SNIa gold sample data.