Evolutionary behaviour of cosmological parameters with dynamical system analysis in f (Q, T) gravity

TL;DR

This paper explores the accelerating universe in $f(Q,T)$ gravity using dynamical system analysis, deriving models with hyperbolic scale factors and analyzing their cosmological parameters to match observations.

Contribution

It introduces specific $f(Q,T)$ gravity models with hyperbolic scale factors and performs dynamical system analysis to study their cosmological behavior and observational consistency.

Findings

Models exhibit accelerated expansion consistent with observations.

Equation of state parameters show marginal variation at present time.

Strong energy conditions are violated in the models.

Abstract

We have investigated the accelerating behaviour of the universe in $f(Q,T)$ gravity in an isotropic and homogeneous space-time. We have initially derive the dynamical parameters in the general form of $f(Q,T)=\alpha Q^{m}+\beta T$ [Xu et al., Eur. Phys. J. C, \textbf{79}, 708 (2019)] and then split it into two cases (i) one with $m=1$ and the (ii) other with $\beta=0$. In the first case, it reduces to the linear form of the functional $f(Q,T)$ and second case leads to the higher power of the nonmetricity $Q$. In an assumed form of the hyperbolic scale factor, the models are constructed and its evolutionary behaviours are studied. The geometrical parameters as well the equation of state parameter are obtained and found to be in the preferred range of the cosmological observations. Marginal variation has been noticed in the behaviour of $\omega$ and $\omega_{eff}$ at present time. The violation of strong energy conditions in both the cases are shown. The dynamical system analysis for the models has been performed.