6,496 research outputs found
Extension of the Thomas-Fermi approximation for trapped Bose-Einstein condensates with an arbitrary number of atoms
By incorporating the zero-point energy contribution we derive simple and
accurate extensions of the usual Thomas-Fermi (TF) expressions for the
ground-state properties of trapped Bose-Einstein condensates that remain valid
for an arbitrary number of atoms in the mean-field regime. Specifically, we
obtain approximate analytical expressions for the ground-state properties of
spherical, cigar-shaped, and disk-shaped condensates that reduce to the correct
analytical formulas in both the TF and the perturbative regimes, and remain
valid and accurate in between these two limiting cases. Mean-field quasi-1D and
-2D condensates appear as simple particular cases of our formulation. The
validity of our results is corroborated by an independent numerical computation
based on the 3D Gross-Pitaevskii equation.Comment: 5 pages, 3 figures. Final version published in Phys. Rev.
Three-dimensional gap solitons in Bose-Einstein condensates supported by one-dimensional optical lattices
We study fundamental and compound gap solitons (GSs) of matter waves in
one-dimensional (1D) optical lattices (OLs) in a three-dimensional (3D)
weak-radial-confinement regime, which corresponds to realistic experimental
conditions in Bose-Einstein condensates (BECs). In this regime GSs exhibit
nontrivial radial structures. Associated with each 3D linear spectral band
exists a family of fundamental gap solitons that share a similar transverse
structure with the Bloch waves of the corresponding linear band. GSs with
embedded vorticity may exist \emph{inside} bands corresponding to other
values of . Stable GSs, both fundamental and compound ones (including vortex
solitons), are those which originate from the bands with lowest axial and
radial quantum numbers. These findings suggest a scenario for the experimental
generation of robust GSs in 3D settings.Comment: 5 pages, 5 figures; v2: matches published versio
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