GROUND STATE AND LOW-EXCITED STATES OF A BOSE GAS IN A FINITE ANISOTROPIC TRAP

2008 ◽  
Vol 22 (28) ◽  
pp. 5003-5014 ◽  
Author(s):  
LIANGHUI WEN ◽  
YONG-LI MA
Keyword(s):  
Ground State ◽  
Collective Excitation ◽  
Three Dimensional ◽  
Finite Amplitude ◽  
Einstein Condensate ◽  
Harmonic Potential ◽  
Excitation Spectra ◽  
Basis Expansion ◽  
Ground State Wavefunction ◽  
Bose Einstein Condensate

The motivation in this paper is to simulate numerically some properties of an interacting Bose–Einstein condensate at zero temperature in an axial symmetry trapping potential with finite amplitude for modeling the practical experimental cases. By use of the basis expansion using three-dimensional harmonic oscillator eigenfunctions, we obtain the ground-state wavefunction and the collective excitation spectra of the system in both usual harmonic potential and different amplitudes of the finite potential. After comparing our results for the finite potential with the data derived from the harmonic potential, we conclude that the finite trap in the practical experiments decreases the entire excitation frequencies in the whole regimes. This decrease is consistent with our analytic prediction qualitatively and agrees well with the experimental data quantitatively.

A CLASS OF CLOSED SOLUTIONS FOR THE BOGOLIUBOV EXCITATIONS ON SMOOTH GROUND STATE OF A TRAPPED BOSE–EINSTEIN CONDENSATE

2005 ◽  
Vol 19 (15) ◽  
pp. 713-720
Author(s):  
YONG-LI MA ◽  
HAICHEN ZHU
Keyword(s):  
Ground State ◽  
Einstein Condensate ◽  
Zero Energy ◽  
Ground State Wavefunction ◽  
New Class ◽  
Bose Einstein Condensate ◽  
Energy Mode ◽  
The One ◽  
Bose Einstein ◽  
Bogoliubov Excitations

Bogoliubov–de Gennes equations (BdGEs) for collective excitations from a trapped Bose–Einstein condensate described by a spatially smooth ground-state wavefunction can be treated analytically. A new class of closed solutions for the BdGEs is obtained for the one-dimensional (1D) and 3D spherically harmonic traps. The solutions of zero-energy mode of the BdGEs are also provided. The eigenfunctions of the excitations consist of zero-energy mode, zero-quantum-number mode and entire excitation modes when the approximate ground state is a background Bose gas sea.

scholarly journals Two distinguishable impurities in BEC: squeezing and entanglement of two Bose polarons

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Christos Charalambous ◽  
Miguel A. Garcia-March ◽  
Aniello Lampo ◽  
Mohammad Mehboud ◽  
Maciej Lewenstein
Keyword(s):  
Sudden Death ◽  
Stochastic Equations ◽  
Einstein Condensate ◽  
Time Limit ◽  
External Potential ◽  
Harmonic Potential ◽  
Bose Einstein Condensate ◽  
Brownian Particles ◽  
Bose Einstein ◽  
Asymptotic Time

We study entanglement and squeezing of two uncoupled impurities immersed in a Bose-Einstein condensate. We treat them as two quantum Brownian particles interacting with a bath composed of the Bogoliubov modes of the condensate. The Langevin-like quantum stochastic equations derived exhibit memory effects. We study two scenarios: (i) In the absence of an external potential, we observe sudden death of entanglement; (ii) In the presence of an external harmonic potential, entanglement survives even at the asymptotic time limit. Our study considers experimentally tunable parameters.

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.

λ-Transition to the Bose-Einstein Condensate

1995 ◽  
Vol 50 (10) ◽  
pp. 921-930 ◽  
Author(s):  
Siegfried Grossmann ◽  
Martin Holthaus
Keyword(s):  
Heat Capacity ◽  
Three Dimensional ◽  
Einstein Condensate ◽  
Einstein Condensation ◽  
Condensation Temperature ◽  
Harmonic Oscillator Potential ◽  
Bose Einstein Condensate ◽  
Bose Einstein ◽  
Analytical Expressions ◽  
Grand Canonical

Abstract We study Bose-Einstein condensation of comparatively small numbers of atoms trapped by a three-dimensional harmonic oscillator potential. Under the assumption that grand canonical statis­tics applies, we derive analytical expressions for the condensation temperature, the ground state occupation, and the specific heat capacity. For a gas of TV atoms the condensation temperature is proportional to N1/3, apart from a downward shift of order N-1/3. A signature of the condensation is a pronounced peak of the heat capacity. For not too small N the heat capacity is nearly discon­tinuous at the onset of condensation; the magnitude of the jump is about 6.6 N k. Our continuum approximations are derived with the help of the proper density of states which allows us to calculate finite-AT-corrections, and checked against numerical computations.

scholarly journals Three-Dimensional Skyrmions with Arbitrary Topological Number in a Ferromagnetic Spin-1 Bose-Einstein Condensate

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Huan-Bo Luo ◽  
Lu Li ◽  
Wu-Ming Liu
Keyword(s):  
Magnetic Field ◽  
Vortex Ring ◽  
Three Dimensional ◽  
Einstein Condensate ◽  
Laser Beams ◽  
Quantization Axis ◽  
Density Distributions ◽  
Bose Einstein Condensate ◽  
Bose Einstein ◽  
Topological Number

AbstractWe propose a new scheme for creating three-dimensional Skyrmions in a ferromagnetic spin-1 Bose-Einstein condensate by manipulating a multipole magnetic field and a pair of counter-propagating laser beams. The result shows that a three-dimensional Skyrmion with topological number Q = 2 can be created by a sextupole magnetic field and the laser beams. Meanwhile, the vortex ring and knot structure in the Skyrmion are found. The topological number can be calculated analytically in our model, which implies that the method can be extended to create Skyrmions with arbitrary topological number. As the examples, three-dimensional Skyrmions with Q = 3, 4 are also demonstrated and are distinguishable by the density distributions with a specific quantization axis. These topological objects have the potential to be realized in ferromagnetic spin-1 Bose-Einstein condensates experimentally.

MODULATION OF ORDER PARAMETER OF EXCITON BOSE-EINSTEIN CONDENSATE IN A RING

2004 ◽  
Vol 18 (27n29) ◽  
pp. 3797-3802 ◽  
Author(s):  
S.-R. ERIC YANG ◽  
Q-HAN PARK ◽  
J. YEO
Keyword(s):  
Ground State ◽  
Order Parameter ◽  
Weak Magnetic Field ◽  
Random Potential ◽  
Einstein Condensate ◽  
Einstein Condensation ◽  
Random Potentials ◽  
Bose Einstein Condensate ◽  
The Mean ◽  
Bose Einstein

We have studied theoretically the Bose-Einstein condensation (BEC) of two-dimensional excitons in a ring with a random variation of the effective exciton potential along the circumference. We derive a nonlinear Gross-Pitaevkii equation (GPE) for such a condensate, which is valid even in the presence of a weak magnetic field. For several types of the random potentials our numerical solution of the ground state of the GPE displays a necklace-like structure. This is a consequence of the interplay between the random potential and a strong nonlinear repulsive term of the GPE. We have investigated how the mean distance between modulation peaks depends on properties of the random potentials.

Dynamics and Ground State Properties of Two-component Bose-Einstein Condensate in Different Hyperfine States

2010 ◽  
Vol 161 (3-4) ◽  
pp. 334-347 ◽  
Author(s):  
Chen Liang ◽  
Kong Wei ◽  
B. J. Ye ◽  
H. M. Wen ◽  
X. Y. Zhou ◽  
...  
Keyword(s):  
Ground State ◽  
Einstein Condensate ◽  
Bose Einstein Condensate ◽  
Ground State Properties ◽  
Two Component ◽  
Bose Einstein
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