Search

In this paper, we study an isotropic and homogeneous Friedmann–Lemaitre–Robertson–Walker cosmological model in Weyl type f (Q , T) gravity with a dynamic deceleration parameter. The solution of the field equations is found using a variable deceleration parameter, viz., q = n + m H , with q the deceleration parameter, n and m constants, and H the Hubble parameter [Tiwari et al., Eur. Phys. J. Plus 132, 1 (2017)]. Then we calculate the values of the model parameters that are most likely to accord with the most recent observational data sets. We make use of the 57 CC points, SN and BAO datasets. We have contracted a graphical representation of the dynamical behavior of the cosmological parameters (the Hubble parameter, the deceleration parameter, the energy density and the equation of state) in terms of the redshift. To investigate the various eras of the universe, the evolution of the statefinder trajectory pairs (s , r) and (q , r) are studied. It is shown that the main energy component of the model is ordinary matter, which behaves initially as the SCDM model and then later as a fluid resembling quintessence, which behaves as the well-known Λ CDM model. A suitable cosmological model is constructed after analyzing the physical parameters of the model, the O m (z) diagnostic analysis. [ABSTRACT FROM AUTHOR]

A cosmological model is described in this study using f (Q , T) gravity, and the parameters are restricted using cosmological data sets. We start out by using a well-motivated form of f (Q , T) as f (Q , T) = m Q + n T , where m and n are model parameters. To solve the field equations, we use the relation that the deceleration parameter is inversely related to the Hubble parameter. In this case, we find that by parametrizing the cosmological parameters the transition redshift between early deceleration and late time acceleration occurs at z t = 0. 4 5 3 − 0. 0 0 1 7 + 0. 0 0 1 7 The positive slope of the Om (z) diagnostic analysis indicates that the model is in a phantom phase. Based on the current study, it seems that f (Q , T) gravity might offer a substitute for dark energy in order to address the current cosmic acceleration. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the accelerated expansion of the Universe in the context of f (Q) modified theory of gravity, where Q is a non-metricity scalar which characterizes the gravitational interaction by using parametrization of the deceleration parameter q = α − β H with f (Q) = ξ + λ Q , where ξ and λ are free parameters constrained by the 57 points of H (z) datasets, 1048 points of Pantheon, 10 points from Baryon Acoustic Oscillations (BAO) datasets and the shift parameters from Planck 2018 of Cosmic Microwave Background (CMB). In the purpose of validating our model, we proceed by the Om diagnostic and the energy conditions. Later we discussed how our model statistically supports Λ CDM using AIC c criterion analysis. [ABSTRACT FROM AUTHOR]

A non-minimally coupled cosmological model is studied in f (R , T) = f 1 (R) + f 2 (R) f 3 (T) gravity for a particular choice of the function in the background of flat Friedmann–Robertson–Walker universe. The modified field equations are solved with the help of a varying deceleration parameter. The time evolution of the model is analyzed for both the dynamic and kinematic quantities. For testing the viability of the results, energy conditions and the statefinder diagnostic are used. It has been shown that this model, which we discussed to examine the phase transition in the expansion of the universe, is compatible with current astrophysical observations, and that the DE model dominating the early universe is Chaplygin gas, while the model dominating the late universe is quintessence. [ABSTRACT FROM AUTHOR]