17,927 research outputs found
Calibrating dipolar interaction in an atomic condensate
We revisit the topic of a dipolar condensate with the recently derived more
rigorous pseudo-potential for dipole-dipole interaction [A. Derevianko, Phys.
Rev. A {\bf 67}, 033607 (2003)]. Based on the highly successful variational
technique, we find that all dipolar effects estimated before (using the bare
dipole-dipole interaction) become significantly larger, i.e. are amplified by
the new velocity-dependent pseudo-potential, especially in the limit of large
or small trap aspect ratios. This result points to a promising prospect for
detecting dipolar effects inside an atomic condensate.Comment: 5 figures, to be publishe
Effective size of a trapped atomic Bose gas
We investigate the temperature-dependent effective size of a trapped
interacting atomic Bose gas within a mean field theory approximation. The
sudden shrinking of the average length, as observed in an earlier experiment by
Wang {\it et al.} [Chin. Phys. Lett. {\bf 20}, 799 (2003)], is shown to be a
good indication for Bose-Einstein condensation (BEC). Our study also supports
the use of the average width of a trapped Bose gas for a nondestructive
calibration of its temperature.Comment: RevTex4, 6 pages, 4 eps figures, to appear in Phys. Rev.
Coherent spin mixing dynamics in a spin-1 atomic condensate
We study the coherent off-equilibrium spin mixing inside an atomic
condensate. Using mean field theory and adopting the single spatial mode
approximation (SMA), the condensate spin dynamics is found to be well described
by that of a nonrigid pendulum, and displays a variety of periodic oscillations
in an external magnetic field. Our results illuminate several recent
experimental observations and provide critical insights into the observation of
coherent interaction-driven oscillations in a spin-1 condensate.Comment: 6 pages, 5 eps figures, update the discussion of the experimental
result
Exotic Topological States with Raman-Induced Spin-Orbit Coupling
We propose a simple experimental scheme to realize simultaneously the
one-dimensional spin-orbit coupling and the staggered spin-flip in ultracold
pseudospin- atomic Fermi gases trapped in square optical lattices. In the
absence of interspecies interactions, the system supports gapped Chern
insulators and gapless topological semimetal states. By turning on the -wave
interactions, a rich variety of gapped and gapless inhomogeneous topological
superfluids can emerge. In particular, a gapped topological Fulde-Ferrell
superfluid, in which the chiral edge states at opposite boundaries possess the
same chirality, is predicted.Comment: 11 pages, 6 figure
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