scholarly journals Thermodynamical Description of Modified Generalized Chaplygin Gas Model of Dark Energy

2015 ◽  
Vol 55 (3) ◽  
pp. 1612-1621 ◽  
Author(s):  
H. Ebadi ◽  
H. Moradpour
Keyword(s):  
Dark Energy ◽  
Chaplygin Gas ◽  
Generalized Chaplygin Gas

scholarly journals OBSERVATIONAL CONSTRAINTS ON THE GENERALIZED CHAPLYGIN GAS

2009 ◽  
Vol 18 (13) ◽  
pp. 2007-2022 ◽  
Author(s):  
SERGIO DEL CAMPO ◽  
J. R. VILLANUEVA
Keyword(s):  
Dark Energy ◽  
Cosmological Model ◽  
Chaplygin Gas ◽  
Observational Constraints ◽  
Energy Component ◽  
Generalized Chaplygin Gas ◽  
Astronomical Data ◽  
Astronomical Observations ◽  
Dark Energy Component ◽  
Two Parameters

In this paper we study a quintessence cosmological model in which the dark energy component is considered to be the generalized Chaplygin gas and the curvature of the three-geometry is taken into account. Two parameters characterize this sort of fluid: ν and α. We use different astronomical data for restricting these parameters. It is shown that the constraint ν ≲ α agrees well enough with the astronomical observations.

scholarly journals DARK MATTER TO DARK ENERGY TRANSITION IN k-ESSENCE COSMOLOGIES

2005 ◽  
Vol 20 (27) ◽  
pp. 2075-2082 ◽  
Author(s):  
L. P. CHIMENTO ◽  
MÓNICA FORTE ◽  
RUTH LAZKOZ
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Kinetic Energy ◽  
Speed Of Sound ◽  
Energy Transition ◽  
Chaplygin Gas ◽  
Large Set ◽  
Generalized Chaplygin Gas ◽  
General Terms ◽  
Transient Models

We implement the transition from dark matter to dark energy in k-essence cosmologies for a very large set of kinetic functions F, in a way alternative to recent proposals which use generalized Chaplygin gas and transient models. Here we require that the pressure admits a power-law expansion around some value of the kinetic energy where the pressure vanishes. In addition, for suitable values of the parameters of the model, the speed of sound of the dark matter will be low. We first present the discussion in fairly general terms, and later consider for illustration two examples.

scholarly journals NEW HOLOGRAPHIC CHAPLYGIN GAS MODEL OF DARK ENERGY

2011 ◽  
Vol 20 (03) ◽  
pp. 281-297 ◽  
Author(s):  
M. MALEKJANI ◽  
A. KHODAM-MOHAMMADI
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Chaplygin Gas ◽  
Accelerated Expansion ◽  
Linear Perturbation ◽  
Generalized Chaplygin Gas ◽  
Infrared Cutoff ◽  
Scalar Field Models ◽  
Linear Perturbation Theory ◽  
Limiting Case

In this work, we investigate the holographic dark energy model with a new infrared cutoff (new HDE model), proposed by Granda and Oliveros. Using this new definition for the infrared cutoff, we establish the correspondence between the new HDE model and the standard Chaplygin gas (SCG), generalized Chaplygin gas (GCG) and modified Chaplygin gas (MCG) scalar field models in a nonflat universe. The potential and dynamics for these scalar field models, which describe the accelerated expansion of the universe, are reconstructed. According to the evolutionary behavior of the new HDE model, we derive the same form of dynamics and potential for the different SCG, GCG and MCG models. We also calculate the squared sound speed of the new HDE model as well as the SCG, GCG and MCG models, and investigate the new HDE Chaplygin gas models from the viewpoint of linear perturbation theory. In addition, all results in the nonflat universe are discussed in the limiting case of the flat universe, i.e. k = 0.

scholarly journals TOWARDS CLASSIFICATION OF SIMPLE DARK ENERGY COSMOLOGICAL MODELS

2007 ◽  
Vol 04 (02) ◽  
pp. 313-323 ◽  
Author(s):  
MAREK SZYDLOWSKI ◽  
ALEKSANDRA KUREK
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cold Dark Matter ◽  
Friedmann Equation ◽  
Chaplygin Gas ◽  
Generalized Chaplygin Gas ◽  
Cosmological Time ◽  
Energy Models ◽  
State Formula ◽  
The Universe

We characterize a class of simple FRW models filled by both dark energy and dark matter in notion of a single potential function of the scale factor a(t); t is the cosmological time. It represents the potential of a fictitious particle — Universe moving in 1-dimensional well V(a) which the positional variable mimics the evolution of the Universe. Then the class of all dark energy models (called a multiverse) can be regarded as a Banach space naturally equipped in the structure of the Sobolev metric. In this paper, we explore the notion of C1 metric introduced in the multiverse which measures distance between any two dark energy models. If we choose cold dark matter as a reference, then we can find how far apart are different models offering explanation of the present accelerating expansion phase of the Universe. We consider both models with dark energy (models with the generalized Chaplygin gas, models with variable coefficient equation of state [Formula: see text] parameterized by redshift z, models with phantom matter) as well as models based on some modification of Friedmann equation (Cardassian models, Dvali–Gabadadze–Porrati brane models). We argue that because observational data still favor the ΛCDM model, all reasonable dark energy models should belong to the nearby neighborhood of this model.

NEW AGEGRAPHIC CHAPLYGIN GAS MODEL WITH VISCOSITY

2011 ◽  
Vol 26 (10) ◽  
pp. 727-737 ◽  
Author(s):  
LEI WANG ◽  
YA-BO WU ◽  
LEI LI ◽  
YUAN GAO ◽  
JIAN GAO
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Chaplygin Gas ◽  
Generalized Chaplygin Gas ◽  
Agegraphic Dark Energy ◽  
New Agegraphic Dark Energy ◽  
Flat Universe ◽  
Special Case

In this paper, motivated by Ref. 31, we study the so-called new agegraphic Chaplygin gas model with viscosity. Concretely, we establish the correspondence between the interacting new agegraphic dark energy (NADE) and variable generalized Chaplygin gas (VGCG) models in non-flat universe on the basis of reviewing related contents for the NADE and VGCG models. Furthermore, we reconstruct the potential of the new agegraphic scalar field as well as the dynamics of the scalar field according to the evolution of the agegraphic dark energy. Finally, we generalize our study to the case of NADE with viscosity, which includes the case without viscosity (ν = 0) as a special case.

scholarly journals GEOMETRICAL DIAGNOSTIC FOR THE GENERALIZED CHAPLYGIN GAS MODEL

2009 ◽  
Vol 18 (11) ◽  
pp. 1741-1748 ◽  
Author(s):  
JIANBO LU ◽  
LIXIN XU
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Equation Of State ◽  
Diagnostic Method ◽  
Chaplygin Gas ◽  
Shift Parameter ◽  
Generalized Chaplygin Gas ◽  
Λcdm Model ◽  
Current Equation

A new diagnostic method, Om, is applied to the generalized Chaplygin gas (GCG) model as the unification of dark matter and dark energy. On the basis of the recently observed data — the Union supernovae, the observational Hubble data, the SDSS baryon acoustic peak and the five-year WMAP shift parameter — we show the discriminations between the GCG model and the ΛCDM model. Furthermore, it is calculated that the current equation of state of dark energy w 0de = -0.964, according to the GCG model.

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