It is demonstrated theoretically that the counter-rotating quadrupole mode in a vortex of Bose-Einstein condensates can decay into a pair of Kelvin modes via the Beliaev process. We calculate the spectral weight of a density-response function within the Bogoliubov framework, taking account of both Beliaev and Landau processes. Good agreement with experiment on [Formula presented] by Bretin et al. [Phys. Rev. Lett. 90, 100403 (2003)] allows us to unambigiously identify the decayed mode as the Kelvin wave propagating along a vortex line.
ASJC Scopus subject areas
- Physics and Astronomy(all)