Redshift Drift in $f(R,T)$ Gravity

TL;DR

This paper constrains the model parameter in $f(R,T)$ gravity using redshift drift measurements, providing a method to test and differentiate cosmological models based on observational data.

Contribution

It introduces a novel approach to constrain $f(R,T)$ gravity parameters through redshift drift analysis, linking cosmography with field equations.

Findings

Constrained $oldsymbol{ extit{ extzeta}}$ in the range $-0.51 oldsymbol{ extkappa}^2$ to $-0.47 oldsymbol{ extkappa}^2$.

Demonstrated the use of redshift drift to test modified gravity theories.

Linked cosmographic series expansion with field equations for parameter estimation.

Abstract

Redshift drift refers to the phenomena that redshift of cosmic objects is a function of time. Measurement of redshift drift is of fundamental importance in physical cosmology and can be utilized to distinguish different cosmological models. Redshift drift can be expressed in two distinct methods. The first method is related to cosmography, where the Redshift drift is given as a series expansion of cosmological parameters, while the second method is written as a function of Hubble parameter and its time derivatives which ultimately involve field equations of a chosen theory of gravity. By equating corresponding terms from both the series, the model parameter(s) of any modified theory of gravity can be constrained. The present note aims at constraining the model parameter $\zeta$ of $f(R,T)$ gravity theory where $f(R,T)= R + \zeta T$. By equating linear terms in redshift $z$ from both the series, we constrain $\zeta$ in the range $-0.51 \kappa^{2} \lesssim \zeta \lesssim -0.47 \kappa^{2}$, where $\kappa^{2}=\frac{8 \pi G}{c^{4}}$.