Vortices in spatially inhomogeneous superfluids

Journal Article · Wed Dec 01 04:00:00 EST 2004 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.70.063620· OSTI ID:20649990

Sheehy, Daniel E; Radzihovsky, Leo ^[1]

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1. Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States)

We study vortices in a radially inhomogeneous superfluid, as realized by a trapped degenerate Bose gas in a uniaxially symmetric potential. We show that, in contrast to a homogeneous superfluid, an off-axis vortex corresponds to an anisotropic superflow whose profile strongly depends on the distance to the trap axis. One consequence of this superflow anisotropy is vortex precession about the trap axis in the absence of an imposed rotation. In the complementary regime of a finite prescribed rotation, we compute the minimum-energy vortex density, showing that in the rapid-rotation limit it is extremely uniform, despite a strongly inhomogeneous (nearly) Thomas-Fermi condensate density {rho}{sub s}(r). The weak radially dependent contribution [{proportional_to}{nabla}{sup 2} ln {rho}{sub s}(r)] to the vortex distribution, that vanishes with the number of vortices N{sub v} as 1/N{sub v}, arises from the interplay between vortex quantum discreteness (namely their inability to faithfully support the imposed rigid-body rotation) and the inhomogeneous superfluid density. This leads to an enhancement of the vortex density at the center of a typical concave trap, a prediction that is in quantitative agreement with recent experiments. One striking consequence of the inhomogeneous vortex distribution is an azimuthally directed, radially shearing superflow.

• OSTI ID: 20649990
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 6 Vol. 70; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ANISOTROPY
BOSE-EINSTEIN CONDENSATION
BOSE-EINSTEIN GAS
DENSITY
DISTANCE
DISTRIBUTION
FORECASTING
POTENTIALS
PRECESSION
ROTATION
SHEAR
SUPERFLUIDITY
THOMAS-FERMI MODEL
TRAPPING
TRAPS
VORTICES