Can the coincidence problem be solved by a cosmological model of coupled dark energy and dark matter?

Poitras, Vincent

doi:10.1007/s10714-014-1732-0

Cited by 4 publications

(3 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some authors have proposed the existence of a mechanism that drives the ratio between the two components close to 1 at late times. An interaction between the dark components would provide just that [5][6][7], while appearing to be compatible with observations. The possibility of such an interaction should be regarded as the natural case for these components, whose natures we do not know, rather than as a particular case of a bigger scenario.…”

Section: Introductionsupporting

confidence: 67%

Analytic study of the effect of dark energy-dark matter interaction on the growth of structures

Marcondes

Landim

Costa

et al. 2016

J. Cosmol. Astropart. Phys.

View full text Add to dashboard Cite

Abstract. Large-scale structure has been shown as a promising cosmic probe for distinguishing and constraining dark energy models. Using the growth index parametrization, we obtain an analytic formula for the growth rate of structures in a coupled dark energy model in which the exchange of energy-momentum is proportional to the dark energy density. We find that the evolution of f σ 8 can be determined analytically once we know the coupling, the dark energy equation of state, the present value of the dark energy density parameter and the current mean amplitude of dark matter fluctuations. After correcting the growth function for the correspondence with the velocity field through the continuity equation in the interacting model, we use our analytic result to compare the model's predictions with large-scale structure observations.

show abstract

Section: Introductionsupporting

confidence: 67%

Analytic study of the effect of dark energy-dark matter interaction on the growth of structures

Marcondes

Landim

Costa

et al. 2016

J. Cosmol. Astropart. Phys.

View full text Add to dashboard Cite

show abstract

“…where Q is the interaction parameter between DM and DE ( [47][48][49]). Note, that unified models of DM and DE have certain issue related to the behavior of the speed of sound, namely they may lead to the production of unphysical oscillations [50].…”

Section: A Basic Equationsmentioning

confidence: 99%

New parametrization for unified dark matter and dark energy

2018

View full text Add to dashboard Cite

In this paper we investigate a new phenomenological parameterization for unified dark matter and dark energy based on the polynomial expansion of the barotropic equation of state parameter w. Our parameterization provides well-behaving evolution of w for both small and big redshifts as well as in the far future. The dark fluid described by our parameterization behaves for big redshifts like a dark matter. Therefore one can parameterize dark energy and dark matter using a single dark fluid, like in the case of the Chaplygin gas. Within this parameterization we consider 2 models: one with DE barotropic parameter fixed to be −1 and the second one, where w = −1 is chosen to match the best fit to the data. We study main cosmological properties of these models at the expansion and perturbation levels. Based on Markov chain Monte Carlo method with currently available cosmic observational data sets, we constrain these models to determine the cosmological parameters at the level of background and clustering of matter. We consider the interaction between DM and DE which directly affects the evolution of matter and its clustering. Our model appears to be perfectly consistent with the ΛCDM model, while providing unification of DE and DM. * Electronic address: z.davaridolatabadi@sci.basu.ac.ir † Electronic address: malekjani@basu.ac.ir

show abstract

“…Some physicists have proposed the existence of a mechanism that drives the ratio ρ DM /ρ DE close to 1 [47][48][49]. In general, allowing an interaction in the dark sector, i.e., between DM and DE, through a non-zero term in the right-hand side of the energy-momentum tensor conservation equation for these components can help alleviate the coincidence problem.…”

Section: The Cosmic Coincidence Problemmentioning

confidence: 99%

Interacting dark energy models in Cosmology and large-scale structure observational tests

Marcondes¹

View full text Add to dashboard Cite

Marcondes, Rafael José FrançaModelos de energia escura com interação em cosmologia e testes observacionais com estruturas em grande escala. São Paulo, 2016. Finally, I would like to show my most profound gratitude to my girlfriend Nathany for her love, dedication and for being so supportive and sweet. v AbstractModern Cosmology offers us a great understanding of the universe with striking precision, made possible by the modern technologies of the newest generations of telescopes. The standard cosmological model, however, is not absent of theoretical problems and open questions. One possibility that has been put forward is the existence of a coupling between dark sectors. The idea of an interaction between the dark components could help physicists understand why we live in an epoch of the universe where dark matter and dark energy are comparable in terms of energy density, which can be regarded as a strange coincidence given that their time evolutions are completely different.Dark matter and dark energy are generally treated as perfect fluids. Interaction is introduced when we allow for a non-zero term in the right-hand side of their individual energy-momentum tensor conservation equations. We proceed with a phenomenological approach to test models of interaction with observations of redshift-space distortions. In a flat universe composed only of these two fluids, we consider separately two forms of interaction, through terms proportional to the densities of both dark energy and dark matter. An analytic expression for the growth rate approximated as f = Ω γ DM , where Ω DM is the percentage contribution from the dark matter to the energy content of the universe and γ is the growth index, is derived in terms of the interaction strength and of other parameters of the model in the first case, while for the second model we show that a non-zero interaction cannot be accommodated by the index growth approximation. The successful expressions obtained are then used to compare the predictions with growth of structure observational data in a Markov Chain Monte Carlo code and we find that the current growth data alone cannot impose constraints on the interaction strength due to their large uncertainties.We also employ observations of galaxy clusters to assess their virial state via the modified Layzer-Irvine equation in order to detect signs of an interaction. We obtain measurements of observed virial ratios, interaction strength, rest virial ratio and departure from equilibrium for a set of clusters. A compounded analysis indicates an interaction strength of 0.29 +2.25−0.40 , compatible with no interaction, but a compounded rest virial ratio of 0.82 +0.13 −0.14 , which means a 2σ confidence level detection. Despite this tension, the method produces encouraging results while still leaves room for improvement, possibly by removing the assumption of small departure from equilibrium.Keywords: Cosmology, Dark energy, Dark matter, Large-scale structure vii Resumo A cosmologia moderna oferece um ótimo entendimento do universo com...

show abstract

Can the coincidence problem be solved by a cosmological model of coupled dark energy and dark matter?

Cited by 4 publications

References 46 publications

Analytic study of the effect of dark energy-dark matter interaction on the growth of structures

Analytic study of the effect of dark energy-dark matter interaction on the growth of structures

New parametrization for unified dark matter and dark energy

Interacting dark energy models in Cosmology and large-scale structure observational tests

Contact Info

Product

Resources

About