2003/09/11 by Tetsuro Nikuni, Allan Griffin · 1 citation
Physics and Astronomy · #Atomic and Subatomic Physics Research #Bose gas #Bose–Einstein condensate #Classical fluids #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Landau damping #Magnetic monopole #Metastability #Phase transition #Physics #Plasma #Quadrupole #Quantum electrodynamics #Quantum mechanics #Quantum, superfluid, helium dynamics #Quasiparticle #Radio-frequency quadrupole #Superfluidity #Thermal #Thermal fluctuations #Thermodynamics #cond-mat.stat-mech
paper · pdf · doi:10.1103/physreva.69.023604
22 pages, 10 figures, submitted to Physical Review A
arxiv created 2003/09/11 · openalex publication_date 2004/02/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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 4He is discussed. We also present calculations for the damping of the analogous m=0 monopole-quadrupole condensate mode in the superfluid phase.