scholarly journals Modified Chaplygin gas cosmology with bulk viscosity

2014 ◽  
Vol 23 (10) ◽  
pp. 1450082 ◽  
Author(s):  
H. B. Benaoum
Keyword(s):  
Numerical Methods ◽  
Cosmological Model ◽  
Bulk Viscosity ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Statefinder Parameters ◽  
Viscosity Parameter ◽  
Model Solutions

In this paper, we investigate the viscous modified Chaplygin gas cosmological model. Solutions for different values of the viscosity parameter are obtained using both analytical and numerical methods. We have calculated the deceleration and defined newly statefinder {r, s} pair in D dimensions. It is shown that when D = 4, the usual statefinder parameters are recovered. Furthermore, we apply the statefinder diagnostic to the MCG model with and without viscosity in D dimensions and explore these parameters graphically.

scholarly journals Bulk Viscous Cosmological Model in Brans-Dicke Theory with New Form of Time Varying Deceleration Parameter

2017 ◽  
Vol 2017 ◽  
pp. 1-24
Author(s):  
G. P. Singh ◽  
Binaya K. Bishi
Keyword(s):  
Equation Of State ◽  
Cosmological Model ◽  
Bulk Viscosity ◽  
Deceleration Parameter ◽  
Chaplygin Gas ◽  
Time Varying ◽  
Modified Chaplygin Gas ◽  
Bulk Viscous ◽  
New Form ◽  
Frw Cosmological Model

We have presented FRW cosmological model in the framework of Brans-Dicke theory. This paper deals with a new proposed form of deceleration parameter and cosmological constant Λ. The effect of bulk viscosity is also studied in the presence of modified Chaplygin gas equation of state (p=Aρ-B/ρn). Furthermore, we have discussed the physical behaviours of the models.

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.

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.

scholarly journals FRW Cosmological Model with Modified Chaplygin Gas and Dynamical System

2012 ◽  
Vol 51 (9) ◽  
pp. 2754-2758 ◽  
Author(s):  
Nairwita Mazumder ◽  
Ritabrata Biswas ◽  
Subenoy Chakraborty
Keyword(s):  
Dynamical System ◽  
Cosmological Model ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Frw Cosmological Model

Interacting modified Chaplygin gas cosmology with varying viscosity

2014 ◽  
Vol 92 (11) ◽  
pp. 1470-1473
Author(s):  
K. Karimiyan ◽  
J. Naji
Keyword(s):  
Energy Density ◽  
Bulk Viscosity ◽  
Deceleration Parameter ◽  
Cosmological Parameters ◽  
Chaplygin Gas ◽  
Baryonic Matter ◽  
Modified Chaplygin Gas ◽  
Hubble Expansion ◽  
Interaction Interaction ◽  
Varying Viscosity

We study interacting modified Chaplygin gas, which has shear and bulk viscosities. We assume bulk viscosity is a function of density, and also consider sign-changeable interaction. Interaction is assumed between modified Chaplygin gas and baryonic matter. Then, the effects of viscosities on the cosmological parameters, such as energy, density, Hubble expansion parameter, scale factor, and deceleration parameter, are investigated. We can consider this model as a toy model of our universe.

A study on the bouncing behavior of modified Chaplygin gas in presence of bulk viscosity and its consequences in the modified gravity framework

2017 ◽  
Vol 14 (12) ◽  
pp. 1750181 ◽  
Author(s):  
Surajit Chattopadhyay
Keyword(s):  
Bulk Viscosity ◽  
Modified Gravity ◽  
State Parameter ◽  
Chaplygin Gas ◽  
Scale Factor ◽  
Accelerated Expansion ◽  
Model Parameters ◽  
Modified Chaplygin Gas ◽  
Frw Universe

The present paper reports a study on the bouncing behavior of the viscous modified Chaplygin gas (MCG) in Einstein as well as modified gravity framework. For a bouncing scale factor proposed by Cai et al., Class. Quantum Grav. 28 (2011) 215011, we have studied the cosmology of MCG in presence of bulk viscosity. In Einstein gravity framework, we have studied the equation of state parameter and it has been found to cross [Formula: see text] indicating the end of the early accelerated expansion and it has also been observed that for flat FRW universe the presence of bulk viscosity induces the crossing of phantom boundary. Role of the model parameters of the MCG has also been investigated before and after the bounce. A Hubble flow dynamics has been carried out and, it was revealed that MCG is capable of realizing inflationary phase as well as an exit from inflation. A [Formula: see text] gravitational paradigm has also been considered, where the MCG density has been reconstructed in presence of bulk viscosity. Role of [Formula: see text] of the bouncing scale factor, describing how fast the bounce takes place, has also been studied in this framework.

scholarly journals Modified Chaplygin Gas Cosmology

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
H. B. Benaoum
Keyword(s):  
Scalar Field ◽  
Cosmological Model ◽  
Chaplygin Gas ◽  
Observational Constraints ◽  
Modified Chaplygin Gas ◽  
Tachyonic Field ◽  
The Relationship

Modified Chaplygin gas as an exotic fluid has been introduced by H. B. Benaoum (2002). Essential features of the modified Chaplygin gas as a cosmological model are discussed. Observational constraints on the parameters of the model have been included. The relationship between the modified Chaplygin gas and a homogeneous minimally coupled scalar field is reevaluated by constructing its self-interacting potential. In addition, we study the role of the tachyonic field in the modified Chaplygin gas cosmological model and the mapping between scalar field and tachyonic field is also considered.

DENSITY PERTURBATIONS AND THE CHAPLYGIN GAS

2009 ◽  
Vol 24 (08n09) ◽  
pp. 1674-1677
Author(s):  
SANDRO SILVA E COSTA
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Power Spectrum ◽  
Cosmological Model ◽  
Chaplygin Gas ◽  
Scale Factor ◽  
Modified Chaplygin Gas ◽  
Modern Cosmology ◽  
Density Perturbations ◽  
The Universe

One approach in modern cosmology consists in supposing that dark matter and dark energy are different manifestations of a single 'quartessential' fluid. Following such idea, this work presents a summary of some studies of the evolution of density perturbations in a flat cosmological model with a modified Chaplygin gas acting as a single component. Our goal is to obtain properties of the model which can be used to distinguish it from another cosmological models which have the same solutions for the general evolution of the scale factor of the universe, even without the construction of the power spectrum. Both our analytical and numerical results clearly indicate as one interesting feature of the model the presence of peaks in the evolution of the density constrast.

scholarly journals Hubble Parameter Corrected Interactions in Cosmology

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
J. Sadeghi ◽  
M. Khurshudyan ◽  
M. Hakobyan ◽  
H. Farahani
Keyword(s):  
Linear Function ◽  
Interaction Parameter ◽  
Bulk Viscosity ◽  
Hubble Parameter ◽  
Cosmological Parameters ◽  
Chaplygin Gas ◽  
Time Dependent ◽  
Modified Chaplygin Gas ◽  
And Behavior ◽  
The Universe

We make steps in a new direction by considering fluids with EoS of more general formF(ρ,P)=0. It is thought that there should be interaction between cosmic fluids, but this assumption for this stage carries only phenomenological character opening a room for different kinds of manipulations. In this paper we will consider a modification of an interactionQ, where we accept that interaction parameterb1(order of unity) inQ=3Hb1ρis time dependent and presented as a linear function of Hubble parameterHof the formb0+btH, wherebandb0are constants. We consider two different models including modified Chaplygin gas and polytropic gas which have bulk viscosity. Then, we investigate problem numerically and analyze behavior of different cosmological parameters concerning fluids and behavior of the universe.

scholarly journals VARYING SPEED OF LIGHT, MODIFIED CHAPLYGIN GAS AND ACCELERATING UNIVERSE

2007 ◽  
Vol 16 (01) ◽  
pp. 117-122 ◽  
Author(s):  
ANUP KUMAR SINGHA ◽  
UJJAL DEBNATH
Keyword(s):  
Gravitational Constant ◽  
Chaplygin Gas ◽  
Accelerating Universe ◽  
Modified Chaplygin Gas ◽  
Speed Of Light ◽  
Statefinder Parameters ◽  
Evolution Of The Universe ◽  
Phantom Model ◽  
The Universe

In this paper, we have considered a model of modified Chaplygin gas in VSL theory with variable gravitational constant G. We have shown that the evolution of the universe starts from radiation era to phantom model. The whole evolution of the universe has been shown diagramatically by using statefinder parameters.

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