Can dark matter be a Bose–Einstein condensate?

By Christian G. Böhmer, Tiberiu Harko. 2007

493 citations recorded by the source corpus.

We consider the possibility that the dark matter which is required to explain the dynamics of the neutral hydrogen clouds at large distances from the galactic centre could be in the form of a Bose–Einstein condensate. To study the condensate we use the non-relativistic Gross–Pitaevskii equation. By introducing the Madelung representation of the wavefunction, we formulate the dynamics of the system in terms of the continuity equation and of the hydrodynamic Euler equations. Hence dark matter can be described as a non-relativistic, Newtonian Bose–Einstein gravitational condensate gas, whose density and pressure are related by a barotropic equation of state. In the case of a condensate with quartic non-linearity, the equation of state is polytropic with index n = 1. In the framework of the Thomas–Fermi approximation the structure of the Newtonian gravitational condensate is described by the Lane–Emden equation, which can be exactly solved. General relativistic configurations with quartic non-linearity are studied, by numerically integrating the structure equations. The basic parameters (mass and radius) of the Bose–Einstein condensate dark matter halos sensitively depend on the mass of the condensed particle and of the scattering length. To test the validity of the model we fit the Newtonian tangential velocity equation of the model with a sample of rotation curves of low surface brightness and dwarf galaxies, respectively. We find a very good agreement between the theoretical rotation curves and the observational data for the low surface brightness galaxies. The deflection of photons passing through the dark matter halos is also analysed, and the bending angle of light is computed. The bending angle obtained for the Bose–Einstein condensate is larger than that predicted by standard general relativistic and dark matter models. The angular radii of the Einstein rings are obtained in the small angle approximation. Therefore the study of the light deflection by galaxies and the gravitational lensing could discriminate between the Bose–Einstein condensate dark matter model and other dark matter models.

Subfields: Atomic and Molecular Physics, and Optics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/76f419be16462a44420413610cf8c8180b2d0d6b

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Citations in the corpus

Angular Momentum and Vortex Formation in Bose-Einstein-Condensed Cold Dark Matter Haloes (2011, methodology): “The reader should henceforth avoid any confusion between the BEC-CDM discussed here and SIDM. c© RAS, MNRAS 000, 1–29 shown in the papers of Arbey, Lesgourges & Salati (2003); Böhmer & Harko (2007) and Böhmer, Martins, Salucci (private communication).”
Mass-radius relation of Newtonian self-gravitating Bose-Einstein condensates with short-range interactions: II. Numerical results (2011, methodology): “Our study connects the non-interacting case studied by Ruffini & Bonazzola (1969) to the Thomas-Fermi limit studied by Böhmer & Harko (2007).”
CONTRASTING GALAXY FORMATION FROM QUANTUM WAVE DARK MATTER, ψDM, WITH ΛCDM, USING PLANCK AND HUBBLE DATA (2015, background): “They are non-thermally generated and can be described by a single coherent wave function (Turner 1983; Goodman 2000; Böhmer & Harko 2007; Sikivie & Yang 2009; Davidson 2015; Guth et al. 2015).”
A Review on the Scalar Field/Bose-Einstein Condensate Dark Matter Model (2013, methodology): “An analysis of the Newtonian regime at Temperature zero can be found in Bohmer and Harko (2007), they assumed the Thomas-Fermi approximation which neglects the anisotropic pressure terms that are relevant only in the boundary of the condensate, the system of equations describing the static BEC in a…”
Growth of perturbations in an expanding universe with Bose-Einstein condensate dark matter (2011, methodology): “For a given value of the scattering length, we obtained the mass-radius relation M(R) connecting the non-interacting case (corresponding to small masses) studied by Ruffini & Bonazzola (1969) to the Thomas-Fermi (TF) limit (corresponding to large masses) investigated by Böhmer & Harko (2007).”