Growth of matter fluctuations in [formula omitted] gravity

Abstract

In this work, I present for the first time the analysis concerning the growth of matter fluctuations in the framework of f(R,T) modified gravity where I presume f(R,T)=R+λT, where R denote the Ricci scalar, T the trace of energy momentum tensor and λ a constant. I first solve the Friedman equations assuming a dust universe (ω=0) for the Hubble parameter H(z) and then employ it in the equation of matter density fluctuations δ(z) to solve for δ(z) and the growth rate f(z). Next, I proceed to show the behavior of f(z) and δ(z) with redshift for some values of λ with observational constraints. Finally, following the prescription of [31], I present an analytical expression for the growth index γ which is redshift dependent and the expression reduces to 3/5 for λ=0, which is the growth index for a dust universe.