Cosmological perturbations during the Bose-Einstein condensation of dark matter

Freitas, R. C.; Gonçalves, S. V. B.

doi:10.1088/1475-7516/2013/04/049

Cited by 18 publications

(19 citation statements)

References 42 publications

(118 reference statements)

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“…This model can also be described by a massless free scalar field. The energy density of the stiff matter is proportional to 1/a(t) 6 and this result indicates that there may have existed a phase earlier than that of radiation, where α = 1/3 and ρ ∝ 1/a(t) 4 , and after inflation in our Universe, which was dominated by stiff matter. This peculiarity motivated us to investigate their behavior in the analyses made here in this work and to consider the implications of the presence of a stiff matter perfect fluid in FRW cosmological models.…”

Section: Introductionmentioning

confidence: 71%

“…Recently the Bose-Einstein condensate (BEC) dark matter (DM), a cosmological model based on condensate state physics, has appeared in several works as an attempt to explain the origin and nature of DM [1,2,3,4,5,6,8] and was initially used to describe DM halos. The equation of state of the BEC can be found from the Gross-Pitaevskii (GP) equation [1,2] and is given by…”

Section: Introductionmentioning

confidence: 99%

“…Recently the cosmological process of the condensation of DM was investigated [5,6] and in this model it is assumed that the condensation process is a phase transition that occurs at some time during the history of the Universe. In this case the normal bosonic DM cools below the critical condensation temperature, that turns to be memorable to form the condensate in which all particles occupy the same ground state.…”

Section: Introductionmentioning

confidence: 99%

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Polytropic equation of state and primordial quantum fluctuations

Freitas

Gonçalves

2014

Eur. Phys. J. C

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We study the primordial Universe in a cosmological model where inflation is driven by a fluid with a polytropic equation of state p = αρ + kρ 1+1/n . We calculate the dynamics of the scalar factor and build a Universe with constant density at the origin. We also find the equivalent scalar field that could create such an equation of state and calculate the corresponding slow-roll parameters. We calculate the scalar perturbations, the scalar power spectrum, and the spectral index.

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Section: Introductionmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Polytropic equation of state and primordial quantum fluctuations

Freitas

Gonçalves

2014

Eur. Phys. J. C

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“…In the present investigations we have developed some basic theoretical tools that could help in discriminating between the standard dark matter and condensate dark matter models. (106) …”

Section: Discussion and Final Remarksmentioning

confidence: 99%

Slowly rotating Bose Einstein condensate galactic dark matter halos, and their rotation curves

et al. 2018

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If dark matter is composed of massive bosons, a Bose-Einstein condensation process must have occurred during the cosmological evolution. Therefore galactic dark matter may be in a form of a condensate, characterized by a strong self-interaction. We consider the effects of rotation on the Bose-Einstein condensate dark matter halos, and we investigate how rotation might influence their astrophysical properties. In order to describe the condensate we use the Gross-Pitaevskii equation, and the Thomas-Fermi approximation, which predicts a polytropic equation of state with polytropic index n = 1. By assuming a rigid body rotation for the halo, with the use of the hydrodynamic representation of the Gross-Pitaevskii equation we obtain the basic equation describing the density distribution of the rotating condensate. We obtain the general solutions for the condensed dark matter density, and we derive the general representations for the mass distribution, boundary (radius), potential energy, velocity dispersion, tangential velocity and for the logarithmic density and velocity slopes, respectively. Explicit expressions for the radius, mass, and tangential velocity are obtained in the first order of approximation, under the assumption of slow rotation. In order to compare our results with the observations we fit the theoretical expressions of the tangential velocity of massive test particles moving in rotata

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“…The general aspects of this model concerning the background evolution and the linear perturbations are already very well understood [24][25][26][27][28][29][30]. But, in order to fully understand the final clustering patterns of the BEC dark matter model high resolution hydrodynamical/N-body simulations are still needed [31].…”

Section: Introductionmentioning

confidence: 99%

Nonlinear clustering during the BEC dark matter phase transition

Freitas¹,

Velten²

2015

Eur. Phys. J. C

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Spherical collapse of the Bose-Einstein condensate (BEC) dark matter model is studied in the ThomasFermi approximation. The evolution of the overdensity of the collapsed region and its expansion rate are calculated for two scenarios. We consider the case of a sharp phase transition (which happens when the critical temperature is reached) from the normal dark matter state to the condensate one and the case of a smooth first order phase transition where there is a continuous conversion of "normal" dark matter to the BEC phase. We present numerical results for the physics of the collapse for a wide range of the model's space parameter, i.e. the mass of the scalar particle m χ and the scattering length l s . We show the dependence of the transition redshift on m χ and l s . Since small scales collapse earlier and eventually before the BEC phase transition, the evolution of collapsing halos in this limit is indeed the same in both the CDM and the BEC models. Differences are expected to appear only on the largest astrophysical scales. However, we argue that the BEC model is almost indistinguishable from the usual dark matter scenario concerning the evolution of nonlinear perturbations above typical clusters scales, i.e., 10 14 M . This provides an analytical confirmation for recent results from cosmological numerical simulations (Schive et al., Nat Phys 10:496, 2014).

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Cosmological perturbations during the Bose-Einstein condensation of dark matter

Cited by 18 publications

References 42 publications

Polytropic equation of state and primordial quantum fluctuations

Polytropic equation of state and primordial quantum fluctuations

Slowly rotating Bose Einstein condensate galactic dark matter halos, and their rotation curves

Nonlinear clustering during the BEC dark matter phase transition

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