Dynamics of Linear Scalar Perturbation in f(Q)+f(T) class of f(Q,T) gravity

TL;DR

This paper investigates the behavior of linear scalar perturbations in a modified gravity model combining f(Q) and f(T) theories, revealing significant deviations from standard cosmology and exploring holographic dark energy effects.

Contribution

It introduces a new analysis of scalar perturbations in the f(Q,T) gravity class, deriving the matter density equation and examining two specific models with and without holographic dark energy.

Findings

Significant divergence from LambdaCDM perturbation behavior

Constraints on the viability of f(Q,T) gravity models

Holographic dark energy influences perturbation dynamics

Abstract

In this work, we study the f(Q,T) model of symmetric teleparallel modified gravity in the framework of cosmological perturbation theory. Using a general approach, we extract the differential matter density equation then we simplify it as a second-order equation by considering the sub-Hubble approximation. Our analysis is then based on two different forms of f(Q,T) that we study in a classic approach and again using Holographic dark energy. Our initial results yield a significant divergence from the perturbed behavior of the LambdaCDM model, imposing stringent constraints on the feasibility of this class of theories but the HDE contribution triggers an interesting discussion.