Dynamic depletion in a Bose-Einstein condensate via a sudden increase of the scattering length

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.

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Resonance in Bose Einstein condensate oscillation from a periodic variation in scattering length

Journal of Physics B Atomic Molecular and Optical Physics ◽

10.1088/0953-4075/36/6/303 ◽

2003 ◽

Vol 36 (6) ◽

pp. 1109-1120 ◽

Cited By ~ 26

Author(s):

Sadhan K Adhikari

Keyword(s):

Scattering Length ◽

Periodic Variation ◽

Einstein Condensate ◽

Bose Einstein Condensate ◽

Bose Einstein

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Entropy of a Turbulent Bose-Einstein Condensate

Entropy ◽

10.3390/e22090956 ◽

2020 ◽

Vol 22 (9) ◽

pp. 956 ◽

Cited By ~ 1

Author(s):

Lucas Madeira ◽

Arnol Daniel García-Orozco ◽

Francisco Ednilson Alves dos Santos ◽

Vanderlei Salvador Bagnato

Keyword(s):

Quantum Turbulence ◽

Excitation Amplitude ◽

Einstein Condensate ◽

Quantum Fluids ◽

Sudden Increase ◽

Bose Einstein Condensate ◽

Onset Of Turbulence ◽

Bose Einstein ◽

Distinct Features ◽

Made In

Quantum turbulence deals with the phenomenon of turbulence in quantum fluids, such as superfluid helium and trapped Bose-Einstein condensates (BECs). Although much progress has been made in understanding quantum turbulence, several fundamental questions remain to be answered. In this work, we investigated the entropy of a trapped BEC in several regimes, including equilibrium, small excitations, the onset of turbulence, and a turbulent state. We considered the time evolution when the system is perturbed and let to evolve after the external excitation is turned off. We derived an expression for the entropy consistent with the accessible experimental data, which is, using the assumption that the momentum distribution is well-known. We related the excitation amplitude to different stages of the perturbed system, and we found distinct features of the entropy in each of them. In particular, we observed a sudden increase in the entropy following the establishment of a particle cascade. We argue that entropy and related quantities can be used to investigate and characterize quantum turbulence.

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