Nonlinear evolution of dark matter and dark energy in the Chaplygin-gas cosmology

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.

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Modified Chaplygin gas as a unified dark matter and dark energy model and cosmic constraints

The European Physical Journal C ◽

10.1140/epjc/s10052-012-1931-3 ◽

2012 ◽

Vol 72 (3) ◽

Cited By ~ 33

Author(s):

Lixin Xu ◽

Yuting Wang ◽

Hyerim Noh

Keyword(s):

Dark Matter ◽

Dark Energy ◽

Dark Energy Model ◽

Chaplygin Gas ◽

Energy Model ◽

Modified Chaplygin Gas

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Variable Chaplygin gas in Kaluza–Klein framework

Canadian Journal of Physics ◽

10.1139/cjp-2017-0873 ◽

2019 ◽

Vol 97 (2) ◽

pp. 117-124 ◽

Cited By ~ 1

Author(s):

M. Salti ◽

O. Aydogdu ◽

A. Tas ◽

K. Sogut ◽

E.E. Kangal

Keyword(s):

Dark Matter ◽

Dark Energy ◽

Chaplygin Gas ◽

Model Parameters ◽

Energy Scenario ◽

Type Ia ◽

The Stability ◽

Best Fit ◽

Matter Energy ◽

Kaluza Klein

We investigate cosmological features of the variable Chaplygin gas (VCG) describing a unified dark matter–energy scenario in a universe governed by the five dimensional (5D) Kaluza–Klein (KK) gravity. In such a proposal, the VCG evolves from the dust-like phase to the phantom or the quintessence phases. It is concluded that the background evolution for the KK-type VCG definition is equivalent to that for the dark energy interacting with the dark matter. Next, after performing neo-classical tests, we calculated the proper, luminosity, and angular diameter distances. Additionally, we construct a connection between the VCG in the KK universe and a homogenous minimally coupled scalar field by introducing its self-interacting potential and also we confirm the stability of the KK-type VCG model by making use of thermodynamics. Moreover, we use data from type Ia supernova, observational H(z) dataset and Planck-2015 results to place constraints on the model parameters. Subsequently, according to the best-fit values of the model parameters we analyze our results numerically.

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

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833836 ◽

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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TOWARDS CLASSIFICATION OF SIMPLE DARK ENERGY COSMOLOGICAL MODELS

International Journal of Geometric Methods in Modern Physics ◽

10.1142/s0219887807002016 ◽

2007 ◽

Vol 04 (02) ◽

pp. 313-323 ◽

Cited By ~ 6

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.

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GEOMETRICAL DIAGNOSTIC FOR THE GENERALIZED CHAPLYGIN GAS MODEL

International Journal of Modern Physics D ◽

10.1142/s021827180901528x ◽

2009 ◽

Vol 18 (11) ◽

pp. 1741-1748 ◽

Cited By ~ 11

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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