Revival of the unified dark energy–dark matter model?

Bento, M. C.; Bertolami, Orfeu; Sen, Anjan A.

doi:10.1103/physrevd.70.083519

Cited by 245 publications

(228 citation statements)

References 52 publications

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“…This rises the disturbing question why they appear to be of the same order of magnitude right now. An explicit coupling between DE and DM [5] could provide a phenomenological solution to this so called "cosmic coincidence problem" [6,7,8,9]. On the other hand, there is theoretical motivation [10] to couple quintessence fields [11,12] to DM (see, however [13]).…”

Section: Introductionmentioning

confidence: 99%

Growth of perturbations in dark matter coupled with quintessence

2005

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We consider the evolution of linear perturbations in models with a nonminimal coupling between dark matter and scalar field dark energy. Growth of matter inhomogeneities in two examples of such models proposed in the literature are investigated in detail. Both of these models are based on a low-energy limit of effective string theory action, and have been previously shown to naturally lead to late acceleration of the universe. However, we find that these models can be ruled out by taking properly into account the impact of the scalar field coupling on the formation of structure in the dark matter density. In particular, when the transition to acceleration in these models begins, the interaction with dark energy enchances the small scale clustering in dark matter much too strongly. We discuss also the role of an effective small scale sound speed squared and the issue of adiabatic initial conditions in models with a coupled dark sector.

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Section: Introductionmentioning

confidence: 99%

Growth of perturbations in dark matter coupled with quintessence

2005

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“…(2), the striking property of the GCG can be found that the energy density behaves as dust like matter at early times; while it behaves like a cosmological constant at late times. Therefore, the GCG model can be regarded as a derivative of the unified dark matter/energy (UDME) scenario (Bento et al 2004). Until now, the GCG model has been constrained using many different types of observational data, such as Type Ia supernovae (SNe Ia) (Fabris et al 2002;Makler et al 2003a;Colistete et al 2003;Silva & Bertolami 2003;Cunha et al 2004;Bertolami et al 2004;Bento et al 2006;Wu & Yu 2007a), cosmic microwave background (CMB) anisotropy (Bento et al 2003a,b;Bean & Dore 2003;Amendola et al 2003), the angular size of the compact radio sources (Zhu 2004), the X-ray gas mass fraction of clusters (Cunha et al 2004;Makler et al 2003b), the Hubble parameter versus redshift data (Wu & Yu 2007b), largescale structure (Bilić et al 2002;Multamäki et al 2004), gravitational lensing surveys (Dev et al , 2004Chen 2003a,b), age measurements of high-z objects ) and lookback time of galaxy clusters (Li et al 2009); as well as various combinations of data (Wu & Yu 2007c;Davis et al 2007;Li et al 2010;Xu & Lu 2010).…”

Section: Introductionmentioning

confidence: 99%

Constraints on the generalized Chaplygin gas model including gamma-ray bursts via a Markov Chain Monte Carlo approach

Liang

Zhu

2011

A&A

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Aims. We investigate observational constraints on the generalized Chaplygin gas (GCG) model including the gamma-ray bursts (GRBs) at high redshift obtained directly from the Union2 type Ia supernovae (SNe Ia) set. Methods. By using the Markov Chain Monte Carlo method, we constrain the GCG model with the cosmology-independent GRBs, as well as the Union2 set, the cosmic microwave background (CMB) observation from the Wilkinson Microwave Anisotropy Probe (WMAP7) result, and the baryonic acoustic oscillation (BAO) observation from the spectroscopic Sloan Digital Sky Survey (SDSS) data release 7 (DR7) galaxy sample.

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“…In the last few years, the unified dark fluid models [1][2][3][4][5][6][7][8][9][10][11][12] were investigated as a possible explanation to an accelerated expansion phase of our Universe [13,14]. These models are inspired by the facts that above 96% of the energy content in the Universe is made of unknown dark component.…”

Section: Introductionmentioning

confidence: 99%

“…These models are inspired by the facts that above 96% of the energy content in the Universe is made of unknown dark component. These unified dark fluid models include the popular generalized Chaplygin gas (gCg) model [4][5][6][7][8] as a sample which is a generalization of the Chaplygin gas (Cg) model or a coined model from the ΛCDM model [9]. Actually, the EoS' of these unified dark fluid are specified in different models.…”

Section: Introductionmentioning

confidence: 99%

Unified dark fluid with constant adiabatic sound speed: Including entropic perturbations

2013

Phys. Rev. D

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In this paper, we continue to study a unified dark fluid model with a constant adiabatic sound speed but with the entropic perturbations. When the entropic perturbations are included, an effective sound speed, which reduces to the adiabatic sound speed when the entropic perturbations are zero, has to be specified as an additional free model parameter. Due to the relations between the adiabatic sound speed and equations of state (EoS) c 2 s,ad (a) = w(a) − d ln(1 + w(a))/3d ln a, the equation of state can be determined up to an integration constant in principle when an adiabatic sound speed is given. Then there are two degrees of freedom to describe the linear perturbations for a fluid. Its micro-scale properties are characterized by its EoS or adiabatic sound speed and an effective sound speed. We take the effective sound speed and adiabatic sound speed as free model parameters and then use the currently available cosmic observational data sets, which include type Ia supernova Union 2.1, baryon acoustic oscillation and WMAP 7-year data of cosmic background radiation, to constrain the possible entropic perturbations and the adiabatic sound speed via the Markov Chain Monte Carlo method. The results show that the cosmic observations favor a small effective sound speed c 2 s,ef f = 0.00155 +0.000319 −0.00155 in 1σ region.

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Revival of the unified dark energy–dark matter model?

Cited by 245 publications

References 52 publications

Growth of perturbations in dark matter coupled with quintessence

Growth of perturbations in dark matter coupled with quintessence

Constraints on the generalized Chaplygin gas model including gamma-ray bursts via a Markov Chain Monte Carlo approach

Unified dark fluid with constant adiabatic sound speed: Including entropic perturbations

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