29 research outputs found
Stability of Accelerated Expansion in Nonlinear Electrodynamics
This paper is devoted to study the phase space analysis of isotropic and
homogenous universe model by taking a noninteracting mixture of electromagnetic
and viscous radiating fluids whose viscous pressure satisfies a nonlinear
version of the Israel-Stewart transport equation. We establish an autonomous
system of equations by introducing normalized dimensionless variables. In order
to analyze stability of the system, we find corresponding critical points for
different values of the parameters. We also evaluate power-law scale factor
whose behavior indicates different phases of the universe model. It is
concluded that bulk viscosity as well as electromagnetic field enhances the
stability of accelerated expansion of the isotropic and homogeneous universe
model.Comment: 17 pages, 5 figures, accepted for publication in EPJ
Viable embedded wormholes and energy conditions in gravity
The current study explores the generalized embedded wormhole solutions in the
background of gravity, where
represents the Ricci scalar and denotes the Gauss-Bonnet
invariant. To investigate the necessary structures of the wormhole solutions we
thoroughly analyzed the energy conditions under
gravity within the anisotropic source of matter. To meet this aim, we consider
spherically symmetric geometry with the most generic gravity model of the
gravity. A modified version of the field equations is calculated for two
different embedded wormhole solutions. All the energy conditions are calculated
and shown graphically with the regional ranges of the model parameter. Further,
the invalid region of the energy conditions confirms the presence of exotic
matter. Finally, we have concluding remarks
Analyzing a higher order model and its implications in the late evolution of the Universe using recent observational datasets
In this research paper, we explore a well-motivated parametrization of the
time-dependent deceleration parameter, characterized by a cubic form, within
the context of late time cosmic acceleration. The current analysis is based on
the gravity theory, by considering the background metric as the
homogeneous and isotropic Friedmann Lema\^itre Robertson Walker (FLRW) metric.
Investigating the model reveals intriguing features of the late universe. To
constrain the model, we use the recent observational datasets, including cosmic
chronometer (CC), Supernovae (SNIa), Baryon Acoustic Oscillation (BAO), Cosmic
Microwave Background Radiation (CMB), Gamma Ray Burst (GRB), and Quasar (Q)
datasets. The joint analysis of these datasets results in tighter constraints
for the model parameters, enabling us to discuss both the physical and
geometrical aspects of the model. Moreover, we determine the present values of
the deceleration parameter (), the Hubble parameter (), and the
transition redshift () from deceleration to acceleration ensuring
consistency with some recent results of Planck 2018. Our statistical analysis
yields highly improved results, surpassing those obtained in previous
investigations. Overall, this study presents valuable insights into the higher
order model and its implications for late-time cosmic acceleration,
shedding light on the nature of the late universe