Superfluid toroidal currents in atomic condensates
McCann, J. F.
American Physical Society
The dynamics of toroidal condensates in the presence of condensate flow and dipole perturbation have been investigated. The Bogoliubov spectrum of a condensate is calculated for an oblate torus using a discrete-variable representation and a spectral method to high accuracy. The transition from spheroidal to toroidal geometry of the trap displaces the energy levels into narrow bands. The lowest-order acoustic modes are quantized with the dispersion relation omegasimilar to\m\omega(s) with m=0,+/-1,+/-2,.... A condensate with toroidal current kappa splits the \m\ co-rotating and counter-rotating pairs by the amount DeltaEapproximate to2\m\h (h) over bar (2)kappa<r(-2)>. Radial dipole excitations are the lowest-energy dissipation modes. For highly occupied condensates the nonlinearity creates an asymmetric mix of dipole circulation and nonlinear shifts in the spectrum of excitations so that the center of mass circulates around the axis of symmetry of the trap. We outline an experimental method to study these excitations.
Bose-Einstein condensate , Vortices , Traps , States , Gases , Ring
Nugent, E., McPeake, D. and McCann, J. F. (2003) 'Superfluid toroidal currents in atomic condensates', Physical Review A, 68(6), 063606 (8pp). doi: 10.1103/PhysRevA.68.063606
© 2003, American Physical Society