435 research outputs found
Structural phase transitions of vortex matter in an optical lattice
We consider the vortex structure of a rapidly rotating trapped atomic
Bose-Einstein condensate in the presence of a co-rotating periodic optical
lattice potential. We observe a rich variety of structural phases which reflect
the interplay of the vortex-vortex and vortex-lattice interactions. The lattice
structure is very sensitive to the ratio of vortices to pinning sites and we
observe structural phase transitions and domain formation as this ratio is
varied.Comment: 4 pages, 3 figure
Excitation spectroscopy of vortex lattices in a rotating Bose-Einstein condensate
Excitation spectroscopy of vortex lattices in rotating Bose-Einstein
condensates is described. We numerically obtain the Bogoliubov-deGenne
quasiparticle excitations for a broad range of energies and analyze them in the
context of the complex dynamics of the system. Our work is carried out in a
regime in which standard hydrodynamic assumptions do not hold, and includes
features not readily contained within existing treatments.Comment: 4 pages, 4 figures. Submitted for publicatio
Excitation spectrum of vortex lattices in rotating Bose-Einstein condensates
Using the coarse grain averaged hydrodynamic approach, we calculate the
excitation spectrum of vortex lattices sustained in rotating Bose-Einstein
condensates. The spectrum gives the frequencies of the common-mode longitudinal
waves in the hydrodynamic regime, including those of the higher-order
compressional modes. Reasonable agreement with the measurements taken in a
recent JILA experiment is found, suggesting that one of the longitudinal modes
reported in the experiment is likely to be the , mode.Comment: 2 figures. Submitted to Physical Review A. v2 contains more
references. No change in the main resul
Watching a superfluid untwist itself: Recurrence of Rabi oscillations in a Bose-Einstein condensate
The order parameter of a condensate with two internal states can continuously
distort in such a way as to remove twists that have been imposed along its
length. We observe this effect experimentally in the collapse and recurrence of
Rabi oscillations in a magnetically trapped, two-component Bose-Einstein
condensate of ^87Rb
Calculation of the interspecies s-wave scattering length in an ultracold Na-Rb vapor
We report the calculation of the interspecies scattering length for the
sodium-rubidium (Na-Rb) system. We present improved hybrid potentials for the
singlet and triplet ground states of the NaRb
molecule, and calculate the singlet and triplet scattering lengths and
for the isotopomers NaRb and NaRb. Using
these values, we assess the prospects for producing a stable two-species
Bose-Einstein condensate in the Na-Rb system.Comment: v2: report correct units in Table captions, fix error in conclusions
for NaRb TBEC. Otherwise, more concise presentation, typos
fixed. 6 pages, 1 figur
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