Dynamical analysis of a hyperbolic solution in Scale-covariant theory

TL;DR

This paper analyzes a flat FLRW cosmological model within Scale-covariant gravity, deriving a hyperbolic function-based solution that describes an ever-accelerating universe with quintessence dark energy, supported by observational data fitting.

Contribution

It introduces a hyperbolic function-based solution in Scale-covariant gravity and constrains model parameters using observational data, highlighting late-time acceleration and quintessence behavior.

Findings

Model exhibits late-time accelerated expansion.

Hubble parameter constrained to H_0=70.979+/-0.021.

Deceleration parameter q_0 approximately -0.54.

Abstract

We study an isotropic flat FLRW-model in Scale-covariant theory of gravity $ f_{\gamma \delta}(\phi) $ \cite{Canuto:1977zz} which is explained in terms of ordinary and covariant differentiation of scalar field $ \phi $. As we know the deceleration parameter is time-dependent, so we consider the deceleration parameter $ q $ as the function of $ t $. Using this methodology, we find all the important cosmological factors in terms of a hyperbolic function of the cosmic time $ t $. In turn, we create the model having the behavior of the late-time universe, which is ever accelerated expanding and faces a Big Freeze at the end. The model shows the quintessence dark energy model from early to late times. We compute the constrained values of Hubble parameter $ H_0=70.979^{+0.021}_{-0.0043} $ and the model parameter $ n=1.24079^{+0.00015}_{-0.00079} $ using joint analysis of the $ OHD $ data of 77-points and Pantheon bin data. The model exhibits point-type singularity, beginning with a point of zero volume, infinite energy density, and temperature. Furthermore, we obtain the present deceleration parameter $ (q_0) \approx {-0.54} $. Also, we examine the ultimate behavior of our model by properly analyzing energy conditions, cosmographical parameters, and Statefinder diagnostic. Finally, the proposed model behaves like a quintessence dark energy model.