Cosmological models described by a mixture of van der Waals fluid and dark energy

Kremer, Gilberto M.

doi:10.1103/physrevd.68.123507

Cited by 92 publications

(81 citation statements)

References 21 publications

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“…As it is well known, the perfect fluid EoS is only a crude approximation of a real fluid that is usually used in cosmology since it represents the simplest way to fit the available data. However, as first shown in the Van der Waals quintessence scenario [29,30] and further demonstrated here, abandoning the perfect fluid EoS still makes it possible to fit the available astrophysical data with the same accuracy so that the use of realistic EoS turns out to be motivated also a posteriori. In our opinion, the era of precision cosmology calls for precision theory so that time is come to abandon approximate description such as the perfect fluid one.…”

Section: Discussionmentioning

confidence: 99%

“…The Van der Waals EoS reduces to the perfect fluid case in the limit α, β → 0. The dynamics of the corresponding cosmological model has been yet investigated both in the framework of UDE models [29] and as a dark energy fluid [30] so that we do not consider it again here. On the other hand, there are other EoS that are worth investigating.…”

Section: Equations Of Statementioning

confidence: 99%

“…Motivated by these considerations, it is therefore worth exploring what are the consequences of abandoning the perfect fluid EoS. A first step in this direction has been performed by Capozziello et al [29] who have considered a model in which a single fluid with a Van der Waals EoS accounts for both dark matter and dark energy (see also [30]). From classical thermodynamics, we know that the Van der Waals EoS is best suited to describe the behaviour of real gas with a particular attention to the phase transitions phenomena.…”

Section: Introductionmentioning

confidence: 99%

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Beyond the perfect fluid hypothesis for the dark energy equation of state

et al. 2006

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Abandoning the perfect fluid hypothesis, we investigate here the possibility that the dark energy equation of state (EoS) w is a nonlinear function of the energy density ρ. To this aim, we consider four different EoS describing classical fluids near thermodynamical critical points and discuss the main features of cosmological models made out of dust matter and a dark energy term with the given EoS. Each model is tested against the data on the dimensionless coordinate distance to Type Ia Supernovae and radio galaxies, the shift and the acoustic peak parameters and the positions of the first three peaks in the anisotropy spectrum of the comic microwave background radation. We propose a possible interpretation of each model in the framework of scalar field quintessence determining the shape of the self interaction potential V (φ) that gives rise to each one of the considered thermodynamical EoS. As a general result, we demonstrate that replacing the perfect fluid EoS with more generar expressions gives both the possibility of successfully solving the problem of cosmic acceleration escaping the resort to phantom models.

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Section: Discussionmentioning

confidence: 99%

Section: Equations Of Statementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Beyond the perfect fluid hypothesis for the dark energy equation of state

et al. 2006

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“…The success of this model has stimulated several different approaches. Recently, a model with a binary mixture whose constituents are described by a VDW fluid and by a dark energy density was also proposed [5]. It is interesting to note that this model can simulate several aspects, namely, an inflationary period where the acceleration grows exponentially; and a present accelerated period where the dark energy density dominates over the energy density of the VDW fluid.…”

Section: Introductionmentioning

confidence: 99%

Van der Waals quintessence stars

Lobo

2007

Phys. Rev. D

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The van der Waals quintessence equation of state is an interesting scenario for describing the late universe, and seems to provide a solution to the puzzle of dark energy, without the presence of exotic fluids or modifications of the Friedmann equations. In this work, the construction of inhomogeneous compact spheres supported by a van der Waals equation of state is explored. These relativistic stellar configurations shall be denoted as van der Waals quintessence stars. Despite of the fact that, in a cosmological context, the van der Waals fluid is considered homogeneous, inhomogeneities may arise through gravitational instabilities. Thus, these solutions may possibly originate from density fluctuations in the cosmological background. Two specific classes of solutions, namely, gravastars and traversable wormholes are analyzed. Exact solutions are found, and their respective characteristics and physical properties are further explored.

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“…• Exotic equation of state: a linear equation of state [8], van der Waals equation of state [9,10], Chaplygin gas [11][12][13], generalized Chaplygin gas [14,15], modified Chaplygin gas [16,17], superfluid Chaplygin gas [18][19][20], inhomogeneous equation of state [21], barotropic fluid model [22], Cardassian model [23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Traversable geometric dark energy wormholes constrained by astrophysical observations

Wang

Meng

2016

Eur. Phys. J. C

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In this paper, we introduce the astrophysical observations into the wormhole research. We investigate the evolution behavior of the dark energy equation of state parameter ω by constraining the dark energy model, so that we can determine in which stage of the universe wormholes can exist by using the condition ω < −1. As a concrete instance, we study the Ricci dark energy (RDE) traversable wormholes constrained by astrophysical observations. Particularly, we find from Fig. 5 of this work, when the effective equation of state parameter ω X < −1 (or z < 0.109), i.e., the null energy condition (NEC) is violated clearly, the wormholes will exist (open). Subsequently, six specific solutions of statically and spherically symmetric traversable wormhole supported by the RDE fluids are obtained. Except for the case of a constant redshift function, where the solution is not only asymptotically flat but also traversable, the five remaining solutions are all non-asymptotically flat, therefore, the exotic matter from the RDE fluids is spatially distributed in the vicinity of the throat. Furthermore, we analyze the physical characteristics and properties of the RDE traversable wormholes. It is worth noting that, using the astrophysical observations, we obtain the constraints on the parameters of the RDE model, explore the types of exotic RDE fluids in different stages of the universe, limit the number of available models for wormhole research, reduce theoretically the number of the wormholes corresponding to different parameters for the RDE model, and provide a clearer picture for wormhole investigations from the new perspective of observational cosmology.a

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Cosmological models described by a mixture of van der Waals fluid and dark energy

Cited by 92 publications

References 21 publications

Beyond the perfect fluid hypothesis for the dark energy equation of state

Beyond the perfect fluid hypothesis for the dark energy equation of state

Van der Waals quintessence stars

Traversable geometric dark energy wormholes constrained by astrophysical observations

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