Kelvin-Tkachenko waves of few-vortex arrays in trapped Bose-Einstein condensates

We have calculated the low-lying elementary excitations of three-dimensional few-vortex arrays in trapped Bose-Einstein condensates. The number of different Kelvin-Tkachenko vortex wave branches matches the number of vortices in the condensate. The lowest odd-parity modes exhibit superfluid gyroscopic vortex motion. Experimentally, these modes could be excited and observed individually or in connection with the formation and decay of quantum turbulence.
Comment: 4 pages, 3 figures, 16 movies http://pra.aps.org/supplemental/PRA/v82/i6/e063627