arXiv:1207.5892 · Journal of Physics Condensed Matter
Zero-energy states in rotating trapped Bose–Einstein condensates
Tapio Simula
Abstract
We have calculated low-lying quasiparticle excitation spectra of rotating three-dimensional Bose-Einstein condensates. We find, as opposed to the prediction of hydrodynamic continuum theories, a minimum in the Tkachenko mode spectrum at intermediate rotation frequencies of the harmonic trap. Such a minimum can harbour a Tkachenko quasiparticle with zero excitation energy. We discuss the experimental signatures of such a zero mode.