The growth of matter perturbations in the f(T) gravity

TL;DR

This paper investigates the growth of matter perturbations within a specific f(T) gravity model, demonstrating its consistency with observational data through the growth index parametrization.

Contribution

It introduces a parametrization of the growth index in f(T) gravity and tests its consistency with observational data, providing new insights into the model's viability.

Findings

The power law f(T) model aligns with observational growth data at 1σ confidence.

The growth index parameters γ₀ and γ₁ are within the allowed observational region.

The parametrization effectively describes the evolution of the growth index in this gravity model.

Abstract

In this paper, we study the growth index of matter density perturbations for the power law model in $f(T)$ gravity. Using the parametrization $\gamma(z)=\gamma_0+\gamma_1 {z\over 1+z}$ for the growth index, which approximates the real evolution of $\gamma(z)$ very well, and the observational data of the growth factor, we find that, at $1\sigma$ confidence level, the power law model in $f(T)$ gravity is consistent with the observations, since the obtained theoretical values of $\gamma_0$ and $\gamma_1$ are in the allowed region.