arXiv subjects

Gaurav Gadbail

Publications and source records attributed to Gaurav Gadbail.

2 recordsLinked to original sources

arXiv2021

Viscous cosmology in the Weyl-type $f(Q,T)$ gravity

Bulk viscosity is the only viscous influence that can change the background dynamics in a homogeneous and isotropic universe. In the present work, we analyze the bulk viscous cosmological model with the bulk viscosity coefficient of the form $ξ=ξ_0+ξ_1H+ξ_2\left(\frac{\dot{H}}{H}+H\right)$ where, $ξ_0$, $ξ_1$ and $ξ_2$ are bulk viscous parameters, and $H$ is the Hubble parameter. We investigate the impact of the bulk viscous parameter on dynamics of the universe in the recently proposed Weyl type $f(Q, T)$ gravity, where $Q$ is the non-metricity, and $T$ is the trace of the matter energy-momentum tensor. The exact solutions to the corresponding field equations are obtained with the viscous fluid and the linear gravity model of the form $f(Q, T)=αQ+\fracβ{6κ^2}T$, where $α$ and $β$ are model parameters. Further, we constrain the model parameters using the $57$ points Hubble dataset and recently released 1048 points Pantheon sample, which shows our model is good congeniality with observations. We study the possible scenarios and the evolution of the universe through the deceleration parameter, the statefinder diagnostics, the Om diagnostics. It is observed that the universe exhibits a transition from a decelerated to an accelerated phase of the universe under certain constraints of model parameters.

gr-qc↗

arXiv2021

Power-law cosmology in Weyl-type $f(Q,T)$ gravity

Gravity is attributed to the spacetime curvature in classical General Relativity (GR). But, other equivalent formulation or representations of GR, such as torsion or non-metricity have altered the perception. We consider the Weyl-type $f(Q, T)$ gravity, where $Q$ represents the non-metricity and $T$ is the trace of energy momentum temsor, in which the vector field $ω_μ$ determines the non-metricity $Q_{μνα}$ of the spacetime. In this work, we employ the well-motivated $f(Q, T)= αQ+ \fracβ{6k^{2}} T$, where $α$ and $β$ are the model parameters. Furthermore, we assume that the universe is dominated by the pressure-free matter, i.e. the case of dust ($p=0$). We obtain the solution of field equations similar to a power-law in Hubble parameter $H(z)$. We investigate the cosmological implications of the model by constraining the model parameter $α$ and $β$ using the recent 57 points Hubble data and 1048 points Pantheon supernovae data. To study various dark energy models, we use statefinder analysis to address the current cosmic acceleration. We also observe the $Om$ diagnostic describing various phases of the universe. Finally, it is seen that the solution which mimics the power-law fits well with the Pantheon data better than the Hubble data.

gr-qc↗