17,240 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
Dipolar effect in coherent spin mixing of two atoms in a single optical lattice site
We show that atomic dipolar effects are detectable in the system that
recently demonstrated two-atom coherent spin dynamics within individual lattice
sites of a Mott state. Based on a two-state approximation for the two-atom
internal states and relying on a variational approach, we have estimated the
spin dipolar effect. Despite the absolute weakness of the dipole-dipole
interaction, it is shown that it leads to experimentally observable effects in
the spin mixing dynamics.Comment: 4 pages, 3 color eps figures, to appear in Phys. Rev. Let
- …