An Anisotropic Kantowski–Sachs Universe with Radiation, Dust and a Phantom Fluid

Oliveira‐Neto, G.; Canedo, D. L.; Monerat, G. A.

doi:10.1007/s13538-022-01137-0

Cited by 9 publications

(7 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In addition to the articles discussed previously, we found in the scientific literature a large number of works with anisotropic models [38][39][40][41][42][43][44] and we see that a complete set of these models includes those already mentioned previously: Bianchi type models [45,46] and the KS model, where the spatial hypersurfaces have the topology of the 2 − ordinary sphere and the real line, S 2 × R 1 . Its metric presents two scale factors of the Universe as follows q q j = --+ ds dt a t dr b t d d sin .…”

Section: Introductionmentioning

confidence: 58%

Kinematic parameters and Raychaudhuri equation in the Kantowski-Sachs model

Silva,

Spalenza,

Gonçalves

2024

Phys. Scr.

View full text Add to dashboard Cite

In this work we present a review of the calculations of homogeneous and anisotropic cosmologicalmodels, particularly the Kantowski-Sachs cosmological model. As an innovativecontribution, we calculate an exact solution to the field equations with a general expressionfor the material content of the universe. We obtain the expressions for energy density in thisgeneral case. We also study the case involving a scalar field. We investigate the evolutiondynamics of the model, encompassing the Hubble, density, and deceleration parameters. Wecalculate the kinematic parameters associated with the model, namely: the scalar expansionΘ, the shear scalar σ, the rotation parameter ω and the parameter RαβUαUβ, alsoknown as Raychaudhuri scalar or convergence condition, all these parameters expressed inthe Raychaudhuri equation.

show abstract

Section: Introductionmentioning

confidence: 58%

Kinematic parameters and Raychaudhuri equation in the Kantowski-Sachs model

Silva,

Spalenza,

Gonçalves

2024

Phys. Scr.

View full text Add to dashboard Cite

show abstract

“…Let us assume, ω r = α ω t (39) where α = 1 to maintain anisotropy. Finally by doing some algebraic manipulation with the field equations ( 13)-( 15) (to eliminate ḃ and b) and using equations ( 36), (38), expression for Rc takes the form Rc = κρR c (40) where…”

Section: Singularity Analysis In a Constrained Ks Modelmentioning

confidence: 99%

Eco-biological Uniqueness of East Kolkata Wetland, a Ramsar Site in India

Chakraborty

Sanyal²,

Ray³

2023

Wetlands Ecology

View full text Add to dashboard Cite

The present work deals with the classical and quantum aspects of the Raychaudhuri equation in the framework of f (T )-gravity theory. In the background of homogeneous and isotropic Friedmann-Lemaître-Robertson-Walker space-time, the Raychaudhuri equation has been formulated and used to examine the focusing theorem and convergence condition for different choices of f (T ). Finally in quantum cosmology, the wave function of the universe has been shown to be the energy eigen function of the time-independent Schrödinger equation of a particle. Also probability measure on the minisuperspace has been examined at zero volume for singularity analysis in the quantum regime. Lastly, the Bohmian trajectory for the present quantum system has been explicitly determined for some particular choices.

show abstract

“…The novelty of the Kantowski-Sachs universe is that in the limit of isotropization, the closed Friedmann-Lemaître-Robertson-Walker (FLRW) is recovered. Thus, Kantowski-Sachs spacetime is an excellent candidate to study the evolution of anisotropies in the presence of curvature in cosmological models; as an example, we refer the reader to [55,56]. We investigate the evolution of the cosmological dynamics and of the physical parameters in Weyl integrable spacetime with an ideal gas as an external fluid.…”

Section: Introductionmentioning

confidence: 99%

Phase‐space analysis of the anisotropies in Weyl integrable spacetime: Kantowski–Sachs cosmology

Paliathanasis

2023

Math Methods in App Sciences

View full text Add to dashboard Cite

We consider anisotropic Kantowski–Sachs cosmology in Weyl integrable spacetime with an ideal gas. We perform a detailed analysis of the dynamics by investigating the stationary points and reconstruct the cosmological history. This analysis gives important information for the initial value problem in Weyl integrable spacetime. We study three cases, in which the scalar field mass depends only on the density of the ideal gas, with or without cosmological constant term, and when there exists an exponential scalar field potential. We conclude that the existence of the nonzero potential function is essential in order that a spatially flat FLRW universe which can describe inflation can be a future attractor.

show abstract

An Anisotropic Kantowski–Sachs Universe with Radiation, Dust and a Phantom Fluid

Cited by 9 publications

References 40 publications

Kinematic parameters and Raychaudhuri equation in the Kantowski-Sachs model

Kinematic parameters and Raychaudhuri equation in the Kantowski-Sachs model

Eco-biological Uniqueness of East Kolkata Wetland, a Ramsar Site in India

Phase‐space analysis of the anisotropies in Weyl integrable spacetime: Kantowski–Sachs cosmology

Contact Info

Product

Resources

About