Frequency and damping of hydrodynamic modes in a trapped Bose-condensed gas

Journal Article · Sun Feb 01 04:00:00 EST 2004 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.69.023604· OSTI ID:20640759

Nikuni, Tetsuro; Griffin, Allan ^[1]

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1. Department of Physics, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-9601 (Japan)

Recently it was shown that the Landau-Khalatnikov two-fluid hydrodynamics describes the collision-dominated region of a trapped Bose condensate interacting with a thermal cloud. We use these equations to discuss the low frequency hydrodynamic collective modes in a trapped Bose gas at finite temperatures. We derive variational expressions based on these equations for both the frequency and damping of collective modes. A new feature is our use of frequency-dependent transport coefficients, which produce a natural cutoff by eliminating the collisionless low-density tail of the thermal cloud. Above the superfluid transition, our expression for the damping in trapped inhomogeneous gases is analogous to the result first obtained by Landau and Lifshitz for uniform classical fluids. We also use the moment method to discuss the crossover from the collisionless to the hydrodynamic region. Recent data for the monopole-quadrupole mode in the hydrodynamic region of a trapped gas of metastable {sup 4}He is discussed. We also present calculations for the damping of the analogous m=0 monopole-quadrupole condensate mode in the superfluid phase.

• OSTI ID: 20640759
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 2 Vol. 69; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
BOSE-EINSTEIN CONDENSATION
BOSE-EINSTEIN GAS
COLLISIONS
DAMPING
DENSITY
FREQUENCY DEPENDENCE
HELIUM 4
HYDRODYNAMICS
METASTABLE STATES
MOMENTS METHOD
QUADRUPOLES
SUPERFLUIDITY
TRAPPING
VARIATIONAL METHODS