Some special solutions in Bianchi type VI0 cosmological models with modified chaplygin gas in general relativity

2015 ◽  
Vol 24 (02) ◽  
pp. 1550017 ◽  
Author(s):  
S. D. Katore ◽  
S. P. Hatkar ◽  
S. N. Bayaskar
Keyword(s):  
Cold Dark Matter ◽  
Bianchi Type ◽  
Complete Solution ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Modified Model ◽  
Geometrical Properties

In the present paper, the role of modified chaplygin gas models in relation with the Bianchi type VI0 universe is examined. For obtaining complete solution of Einstein field equations, it is assumed that expansion scalar in the model is proportional to shear scalar and equation of state of this modified model is valid from the radiation era to the Lambda cold dark matter (ΛCDM) model. State finder and various physical, geometrical properties have also been discussed.

scholarly journals Role of a chameleon field in the presence of variable modified Chaplygin gas in Brans–Dicke theory

2012 ◽  
Vol 90 (2) ◽  
pp. 131-135 ◽  
Author(s):  
Shuvendu Chakraborty ◽  
Ujjal Debnath
Keyword(s):  
Scalar Field ◽  
Analytic Function ◽  
Chaplygin Gas ◽  
Conservation Equation ◽  
Modified Chaplygin Gas ◽  
Field Equations ◽  
Variable Modified Chaplygin Gas ◽  
The Universe ◽  
Friedmann Robertson Walker

In this work, we have considered the Friedmann–Robertson–Walker model of the universe for Brans–Dicke (BD) theory with a BD scalar field as a chameleon field. First we have transformed the field equations and conservation equation from Jordan’s frame to Einstein’s frame. We have shown that, in the presence of a variable modified Chaplygin gas (VMCG), the potential function V and another analytic function f always increase with respect to the BD–chameleon scalar field [Formula: see text] but decrease with time t for pure Chaplygin gas, modified Chaplygin gas, and VMCG models.

scholarly journals Bianchi Type-VI0 Cosmological Model with Special Form of Scale Factor in Sen-Dunn Theory of Gravitation

2021 ◽  
Vol 13 (1) ◽  
pp. 137-143
Author(s):  
D. Basumatay ◽  
M. Dewri
Keyword(s):  
Cosmological Model ◽  
Special Form ◽  
Bianchi Type ◽  
Scale Factor ◽  
Type I ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Geometrical Properties ◽  
Theory Of Gravitation ◽  
Bianchi Type Vi0

A Bianchi Type-VI0 cosmological model with a special form of scale factor is studied. Einstein field equations in Sen-Dunn theory are obtained and solved for exact solutions. This solution gives a scenario of the dark energy model which tends to a ɅCDM model. The physical and geometrical properties are also obtained and analyzed with the present day observations.

RADIATING COLLAPSE WITH VANISHING WEYL STRESSES

2005 ◽  
Vol 14 (03n04) ◽  
pp. 667-676 ◽  
Author(s):  
S. D. MAHARAJ ◽  
M. GOVENDER
Keyword(s):  
Irreversible Thermodynamics ◽  
Temperature Profiles ◽  
Junction Conditions ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Extended Irreversible Thermodynamics ◽  
Recent Approach ◽  
Dust Solution ◽  
Limiting Case

In a recent approach in modeling a radiating relativistic star undergoing gravitational collapse the role of the Weyl stresses was emphasized. It is possible to generate a model which is physically reasonable by approximately solving the junction conditions at the boundary of the star. In this paper we demonstrate that it is possible to solve the Einstein field equations and the junction conditions exactly. This exact solution contains the Friedmann dust solution as a limiting case. We briefly consider the radiative transfer within the framework of extended irreversible thermodynamics and show that relaxational effects significantly alter the temperature profiles.

scholarly journals ROLE OF GENERALIZED COSMIC CHAPLYGIN GAS IN ACCELERATING UNIVERSE: A FIELD THEORETICAL PRESCRIPTION

2013 ◽  
Vol 28 (22) ◽  
pp. 1350102 ◽  
Author(s):  
PRABIR RUDRA
Keyword(s):  
Dark Energy ◽  
Chaplygin Gas ◽  
Point Of View ◽  
Accelerating Universe ◽  
Theoretical Point ◽  
Modified Chaplygin Gas ◽  
Statefinder Parameters ◽  
Generalized Cosmic Chaplygin Gas ◽  
The Given

In this paper, we investigate the role played by dark energy (DE) in the form of Generalized cosmic Chaplygin gas in an accelerating universe described by FRW cosmology. We have tried to describe the model from the theoretical point of view of a field, by introducing a scalar field ϕ and a self-interacting potential V(ϕ). The corresponding expressions for the field are obtained for the given model. Statefinder parameters have been used to characterize the dark energy model. Plots have been generated for characterizing different phases of universe diagrammatically and a comparative study is performed with the Modified Chaplygin gas model. As an outcome of the study, Generalized cosmic Chaplygin gas is identified as a much less constrained form of dark energy as compared to modified Chaplygin gas.

scholarly journals The Gravitomagnetism in the Solar System

2017 ◽  
Vol 45 ◽  
pp. 1760052
Author(s):  
Flavia Rocha ◽  
Manuel Malheiro ◽  
Rubens Marinho
Keyword(s):  
Mass Density ◽  
Slow Motion ◽  
Weak Field ◽  
Einstein Equations ◽  
Dipole Potential ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Perihelion Advance ◽  
Motion Approximation

In 1918, Joseph Lense and Hans Thirring discovered the gravitomagnetic (GM) effect of Einstein field equations in weak field and slow motion approximation. They showed that Einstein equations in this approximation can be written as in the same form as Maxwell’s equation for electromagnetism. In these equations the charge and electric current are replaced by the mass density and the mass current. Thus, the gravitomagnetism formalism in astrophysical system is used with the mass assuming the role of the charge. In this work, we present the deduction of gravitoelectromagnetic equations and the analogue of the Lorentz force in the gravitomagnetism. We also discuss the problem of Mercury’s perihelion advance orbit, we propose solutions using GM formalism using a dipole-dipole potential for the Sun-Planet interaction.

scholarly journals Role of modified Chaplygin gas in accelerated universe

2004 ◽  
Vol 21 (23) ◽  
pp. 5609-5617 ◽  
Author(s):  
Ujjal Debnath ◽  
Asit Banerjee ◽  
Subenoy Chakraborty
Keyword(s):  
Chaplygin Gas ◽  
Modified Chaplygin Gas

scholarly journals Accelerating dark energy cosmological model in two fluids with hybrid scale factor

2017 ◽  
Vol 14 (09) ◽  
pp. 1750124 ◽  
Author(s):  
B. Mishra ◽  
P. K. Sahoo ◽  
Pratik P. Ray
Keyword(s):  
Dark Energy ◽  
Late Phase ◽  
Scale Factor ◽  
Accelerating Universe ◽  
Late Time ◽  
Field Equations ◽  
Geometrical Properties ◽  
Two Fluids ◽  
The Universe

In this paper, we have investigated the anisotropic behavior of the accelerating universe in Bianchi V spacetime in the framework of General Relativity (GR). The matter field we have considered is of two non-interacting fluids, i.e. the usual string fluid and dark energy (DE) fluid. In order to represent the pressure anisotropy, the skewness parameters are introduced along three different spatial directions. To achieve a physically realistic solutions to the field equations, we have considered a scale factor, known as hybrid scale factor, which is generated by a time-varying deceleration parameter. This simulates a cosmic transition from early deceleration to late time acceleration. It is observed that the string fluid dominates the universe at early deceleration phase but does not affect nature of cosmic dynamics substantially at late phase, whereas the DE fluid dominates the universe in present time, which is in accordance with the observations results. Hence, we analyzed here the role of two fluids in the transitional phases of universe with respect to time which depicts the reason behind the cosmic expansion and DE. The role of DE with variable equation of state parameter (EoS) and skewness parameters, is also discussed along with physical and geometrical properties.

scholarly journals DYNAMICAL EVOLUTION OF INTERACTING MODIFIED CHAPLYGIN GAS

2009 ◽  
Vol 18 (11) ◽  
pp. 1785-1800 ◽  
Author(s):  
SONG LI ◽  
YONGGE MA ◽  
YUN CHEN
Keyword(s):  
Cold Dark Matter ◽  
Dynamical Evolution ◽  
Chaplygin Gas ◽  
Coupling Constants ◽  
Modified Chaplygin Gas ◽  
Coincidence Problem ◽  
Final State ◽  
Energy Models ◽  
Scaling Solution ◽  
The Universe

The cosmological model of the modified Chaplygin gas (MCG) interacting with cold dark matter is studied. Our attention is focused on the final state of the universe in the model. It turns out that there exists a stable scaling solution, which provides the possibility of alleviating the coincidence problem. In addition, we investigate the effect of the coupling constants c1 and c2 on the dynamical evolution of this model from the statefinder viewpoint. It is found that the coupling constants play a significant role during the dynamical evolution of the interacting MCG model. Furthermore, we can distinguish this interacting model from other dark energy models in the s–r plane.

Modified Chaplygin gas equation of state on viscous dissipative extended holographic Ricci dark energy and the cosmological consequences

2016 ◽  
Vol 26 (06) ◽  
pp. 1750042 ◽  
Author(s):  
Surajit Chattopadhyay
Keyword(s):  
Dark Energy ◽  
Bulk Viscosity ◽  
Cold Dark Matter ◽  
Viscosity Coefficient ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Ricci Dark Energy ◽  
Dissipative Term ◽  
Generalized Second Law ◽  
The Universe

The present paper reports a study on modified Chaplygin gas (MCG)-based reconstruction scheme for extended holographic Ricci dark energy (EHRDE) in the presence of viscous type dissipative term. The dissipative effect has been described by using Eckart approach. Under the assumption that the universe is filled with MCG–EHRDE under the influence of bulk viscosity we have studied the cosmological dynamics, where the bulk viscosity coefficient has been chosen in a particular time varying form [Formula: see text], where [Formula: see text] and [Formula: see text] are constant coefficients and [Formula: see text] is the Hubble parameter. Furthermore, we have reconstructed the potential and dynamics of viscous MCG–EHRDE as scalar field. Thereafter we have studied the statefinder trajectories to discern its departure from [Formula: see text] cold dark matter ([Formula: see text]CDM) and finally investigated validity of the generalized second law (GSL) of thermodynamics considering event horizon as the enveloping horizon of the universe.

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