Gravitational waves for variable modified Chaplygin gas and some parametrizations of dark energy in the background of FRW universe

2020 ◽  
Vol 135 (2) ◽  
Author(s):  
Ujjal Debnath
Keyword(s):  
Dark Energy ◽  
Gravitational Waves ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Frw Universe ◽  
Variable Modified Chaplygin Gas

A VARIABLE MODIFIED CHAPLYGIN GAS MODEL WITH INTERACTION

2009 ◽  
Vol 18 (12) ◽  
pp. 1851-1862 ◽  
Author(s):  
LILI XING ◽  
YUANXING GUI ◽  
CHUNYAN WANG
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
State Parameter ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Phantom Divide ◽  
Energy Models ◽  
Big Rip ◽  
Variable Modified Chaplygin Gas ◽  
The Future

We consider in this paper a variable modified Chaplygin gas (VMCG) model for describing the unification of dark energy and dark matter, in which dark energy interacts with dark matter. Concretely, the evolution of the VMCG model with interaction is discussed and the statefinder diagnostic for the model is performed. By analysis, we find that the effective state parameter of dark energy can cross the phantom divide wΛ= -1 and our universe will not end up with a Big Rip in the future. Furthermore, we perform a statefinder analysis on this scenario and show the discrimination between this scenario and other dark energy models.

EVOLUTION OF VARIABLE MODIFIED CHAPLYGIN GAS MODEL

2009 ◽  
Vol 24 (09) ◽  
pp. 683-691 ◽  
Author(s):  
LILI XING ◽  
YUANXING GUI ◽  
LIXIN XU ◽  
JIANBO LU
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Early Time ◽  
State Parameter ◽  
Growth Index ◽  
Chaplygin Gas ◽  
The State ◽  
Modified Chaplygin Gas ◽  
Phantom Divide ◽  
Variable Modified Chaplygin Gas

We consider a variable modified Chaplygin gas (VMCG) model with unified dark energy and dark matter. Some cosmological quantities are studied, such as the state parameter of dark energy wde, the fractional energy densities Ωi(i respectively denotes baryons, dark matter, dark energy), the deceleration parameter q and the growth index f. By analysis, we find that the state parameter of dark energy can cross the phantom divide wΛ= -1, the behavior of VMCG is similar to radiation in the early time and will be quinessence model in the future. Therefore the universe will not end up with Big Rip.

Cosmological constraints on the variable modified Chaplygin gas model by using MCMC approach

2015 ◽  
Vol 24 (08) ◽  
pp. 1550059 ◽  
Author(s):  
Jian-bin Chen ◽  
Zhen-qi Liu ◽  
Lili Xing
Keyword(s):  
Apparent Horizon ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Acoustic Oscillations ◽  
Microwave Background ◽  
Mean Values ◽  
Cosmological Constraints ◽  
Variable Modified Chaplygin Gas ◽  
Type Ia ◽  
Ia Supernovae

We investigate the cosmological constraints on the variable modified Chaplygin gas (VMCG) model from the latest observational data: Union2 dataset of Type Ia supernovae (SNIa), the observational Hubble data (OHD), the baryon acoustic oscillations (BAO) and the cosmic microwave background (CMB) data. By using the Markov chain Monte Carlo (MCMC) method, we obtain the mean values of parameters in the flat model: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]. Furthermore, we investigate the thermodynamical properties of VMCG model at apparent horizon, event horizon and particle horizon respectively.

FRW viscous modified cosmic Chaplygin gas cosmology in the presence of cosmological constant

2019 ◽  
Vol 16 (09) ◽  
pp. 1950141 ◽  
Author(s):  
G. S. Khadekar ◽  
Aina Gupta ◽  
Kalpana Pande
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Cosmological Constant ◽  
Chaplygin Gas ◽  
Frw Universe ◽  
Dark Energy Density ◽  
Linear Combinations ◽  
Linear Differential ◽  
The Stability ◽  
Cardassian Universe

In this paper, we study viscous Modified Cosmic Chaplygin Gas (MCCG) in the presence of cosmological constant in flat FRW universe. We assume that bulk viscosity [Formula: see text] and cosmological constant [Formula: see text] are the linear combinations of two terms, one is constant and other is a function of dark energy density [Formula: see text]. In this framework, we solve the non-linear differential equation analytically and numerically and obtain time dependent dark energy density. We also consider two separate cases of early and late universe and discussed the evolution of dark energy density. We investigate the effect of viscosity and cosmological constant to the evolution of universe and discuss the stability of the model by square of speed of sound. Finally, we compare our model with Cardassian universe.

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 Astronomical bounds on the modified Chaplygin gas as a unified dark fluid model

2019 ◽  
Vol 623 ◽  
pp. A28
Author(s):  
Hang Li ◽  
Weiqiang Yang ◽  
Liping Gai
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Fluid Model ◽  
Chaplygin Gas ◽  
Linear Perturbation ◽  
Model Parameters ◽  
Modified Chaplygin Gas ◽  
Dark Fluid ◽  
Type Ia ◽  
Linear Perturbation Theory

The modified Chaplygin gas could be considered to abide by the unified dark fluid model because the model might describe the past decelerating matter dominated era and at present time it provides an accelerating expansion of the Universe. In this paper, we have employed the Planck 2015 cosmic microwave background anisotropy, type-Ia supernovae, observed Hubble parameter data sets to measure the full parameter space of the modified Chaplygin gas as a unified dark matter and dark energy model. The model parameters Bs, α, and B determine the evolutional history of this unified dark fluid model by influencing the energy density ρMCG = ρMCG0[Bs + (1 − Bs)a−3(1 + B)(1 + α)]1/(1 + α). We assumed the pure adiabatic perturbation of unified modified Chaplygin gas in the linear perturbation theory. In the light of Markov chain Monte Carlo method, we find that Bs = 0.727+0.040+0.075−0.039−0.079, α = −0.0156+0.0982+0.2346−0.1380−0.2180, B = 0.0009+0.0018+0.0030−0.0017−0.0030 at 2σ level. The model parameters α and B are very close to zero and the nature of unified dark energy and dark matter model is very similar to cosmological standard model ΛCDM.

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