scholarly journals Gravitational collapse of Bose-Einstein condensate dark matter halos

2014 ◽  
Vol 89 (8) ◽  
Author(s):  
Tiberiu Harko
Keyword(s):  
Dark Matter ◽  
Gravitational Collapse ◽  
Einstein Condensate ◽  
Dark Matter Halos ◽  
Bose Einstein Condensate ◽  
Bose Einstein

scholarly journals Jeans instability and turbulent gravitational collapse of Bose–Einstein condensate dark matter halos

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
Tiberiu Harko
Keyword(s):  
Dark Matter ◽  
Gravitational Collapse ◽  
Separation Of Variables ◽  
Einstein Condensate ◽  
Wave Number ◽  
Radial Coordinate ◽  
Dark Matter Halos ◽  
Bose Einstein Condensate ◽  
Jeans Instability ◽  
Bose Einstein

Abstract We consider the Jeans instability and the gravitational collapse of the rotating Bose–Einstein condensate dark matter halos, described by the zero temperature non-relativistic Gross–Pitaevskii equation, with repulsive interparticle interactions. In the Madelung representation of the wave function, the dynamical evolution of the galactic halos is described by the continuity and the hydrodynamic Euler equations, with the condensed dark matter satisfying a polytropic equation of state with index $$n=1$$n=1. By considering small perturbations of the quantum hydrodynamical equations we obtain the dispersion relation and the Jeans wave number, which includes the effects of the vortices (turbulence), of the quantum pressure and of the quantum potential, respectively. The critical scales above which condensate dark matter collapses (the Jeans radius and mass) are discussed in detail. We also investigate the collapse/expansion of rotating condensed dark matter halos, and we find a family of exact semi-analytical solutions of the hydrodynamic evolution equations, derived by using the method of separation of variables. An approximate first order solution of the fluid flow equations is also obtained. The radial coordinate dependent mass, density and velocity profiles of the collapsing/expanding condensate dark matter halos are obtained by using numerical methods.

scholarly journals DARK MATTER AXIONS

2010 ◽  
Vol 25 (02n03) ◽  
pp. 554-563 ◽  
Author(s):  
P. SIKIVIE
Keyword(s):  
Dark Matter ◽  
Particle Physics ◽  
Cold Dark Matter ◽  
Einstein Condensate ◽  
Dark Matter Halos ◽  
Linear Regime ◽  
Bose Einstein Condensate ◽  
Invisible Axion ◽  
Bose Einstein ◽  
The Universe

The hypothesis of an 'invisible' axion was made by Misha Shifman and others, approximately thirty years ago. It has turned out to be an unusually fruitful idea, crossing boundaries between particle physics, astrophysics and cosmology. An axion with mass of order 10-5 eV (with large uncertainties) is one of the leading candidates for the dark matter of the universe. It was found recently that dark matter axions thermalize and form a Bose-Einstein condensate (BEC). Because they form a BEC, axions differ from ordinary cold dark matter (CDM) in the non-linear regime of structure formation and upon entering the horizon. Axion BEC provides a mechanism for the production of net overall rotation in dark matter halos, and for the alignment of cosmic microwave anisotropy multipoles. Because there is evidence for these phenomena, unexplained with ordinary CDM, an argument can be made that the dark matter is axions.

scholarly journals Rotation curves of rotating Galactic Bose-Einstein condensate dark matter halos

2014 ◽  
Vol 89 (6) ◽  
Author(s):  
F. S. Guzmán ◽  
F. D. Lora-Clavijo ◽  
J. J. González-Avilés ◽  
F. J. Rivera-Paleo
Keyword(s):  
Dark Matter ◽  
Einstein Condensate ◽  
Dark Matter Halos ◽  
Rotation Curves ◽  
Bose Einstein Condensate ◽  
Bose Einstein

scholarly journals Two-component axionic dark matter halos

2020 ◽  
Vol 35 (26) ◽  
pp. 2050227 ◽  
Author(s):  
Gennady P. Berman ◽  
Vyacheslav N. Gorshkov ◽  
Vladimir I. Tsifrinovich ◽  
Marco Merkli ◽  
Vladimir V. Tereshchuk
Keyword(s):  
Dark Matter ◽  
Ground State ◽  
Mass Density ◽  
Mean Field ◽  
Einstein Condensate ◽  
Dark Matter Halo ◽  
Bose Einstein Condensate ◽  
Interesting Connection ◽  
Two Component ◽  
Bose Einstein

We consider a two-component dark matter halo (DMH) of a galaxy containing ultra-light axions (ULA) of different mass. The DMH is described as a Bose–Einstein condensate (BEC) in its ground state. In the mean-field (MF) limit, we have derived the integro-differential equations for the spherically symmetrical wave functions of the two DMH components. We studied, numerically, the radial distribution of the mass density of ULA and constructed the parameters which could be used to distinguish between the two- and one-component DMH. We also discuss an interesting connection between the BEC ground state of a one-component DMH and Black Hole temperature and entropy, and Unruh temperature.

scholarly journals Supplying dark energy from scalar field dark matter

2018 ◽  
Vol 27 (09) ◽  
pp. 1850100
Author(s):  
Merab Gogberashvili ◽  
Alexander Sakharov
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Gordon Equation ◽  
Einstein Condensate ◽  
Scalar Particles ◽  
Bose Einstein Condensate ◽  
Constant Solution ◽  
Klein Gordon ◽  
Free Parameters ◽  
Bose Einstein

We consider the hypothesis that dark matter (DM) and dark energy (DE) consist of ultra-light self-interacting scalar particles. It is found that the Klein–Gordon equation with only two free parameters (mass and self-coupling) on a Schwarzschild background, at the galactic length-scales has the solution which corresponds to Bose–Einstein Condensate (BEC), behaving as DM, while the constant solution at supra-galactic scales can explain DE.

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