scholarly journals Collective excitation of a Bose-Einstein condensate by modulation of the atomic scattering length

2010 ◽  
Vol 81 (5) ◽  
Author(s):  
S. E. Pollack ◽  
D. Dries ◽  
R. G. Hulet ◽  
K. M. F. Magalhães ◽  
E. A. L. Henn ◽  
...  
Keyword(s):  
Collective Excitation ◽  
Scattering Length ◽  
Einstein Condensate ◽  
Bose Einstein Condensate ◽  
Atomic Scattering ◽  
Bose Einstein

scholarly journals Jeans Instability of Dissipative Self-Gravitating Bose–Einstein Condensates with Repulsive or Attractive Self-Interaction: Application to Dark Matter

Universe ◽  
2020 ◽  
Vol 6 (12) ◽  
pp. 226
Author(s):  
Pierre-Henri Chavanis
Keyword(s):  
Dark Matter ◽  
Scattering Length ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Einstein Condensate ◽  
Wave Number ◽  
Arbitrary Form ◽  
Bose Einstein Condensate ◽  
Jeans Instability ◽  
Bose Einstein

We study the Jeans instability of an infinite homogeneous dissipative self-gravitating Bose–Einstein condensate described by generalized Gross–Pitaevskii–Poisson equations [Chavanis, P.H. Eur. Phys. J. Plus2017, 132, 248]. This problem has applications in relation to the formation of dark matter halos in cosmology. We consider the case of a static and an expanding universe. We take into account an arbitrary form of repulsive or attractive self-interaction between the bosons (an attractive self-interaction being particularly relevant for the axion). We consider both gravitational and hydrodynamical (tachyonic) instabilities and determine the maximum growth rate of the instability and the corresponding wave number. We study how they depend on the scattering length of the bosons (or more generally on the squared speed of sound) and on the friction coefficient. Previously obtained results (notably in the dissipationless case) are recovered in particular limits of our study.

scholarly journals Anharmonicity-induced criticality of collective excitation in a trapped Bose–Einstein condensate

2018 ◽  
Vol 32 (31) ◽  
pp. 1850345
Author(s):  
Qun Wang ◽  
Bo Xiong
Keyword(s):  
Collective Mode ◽  
Collective Excitation ◽  
Einstein Condensate ◽  
Low Energy ◽  
Many Body ◽  
Bose Einstein Condensate ◽  
Large Numbers ◽  
Many Body Systems ◽  
Repulsive Forces ◽  
Bose Einstein

We investigate the low-energy excitations of a dilute atomic Bose gas confined in a anharmonic trap interacting with repulsive forces. The dispersion law of both surface and compression modes is derived and analyzed for large numbers of atoms in the trap, which show two branches of excitation and appear two critical values, where one of them indicates collective excitation which would be unstable dynamically, and the other one indicates the existing collective mode with lower frequency under anharmonic influence than that in harmonic trapping case. Our work reveals the key role played by the anharmonicity and interatomic forces which introduce a rich structure in the dynamic behavior of these new many-body systems.

Sign in / Sign up

Export Citation Format

Share Document