Small-amplitude normal modes of a vortex in a trapped Bose-Einstein condensate - art. no. 063603

We consider a rotating axisymmetric trap containing a small Bose-Einstein c ondensate with a singly quantized vortex near the axis of symmetry. A time- dependent variational Lagrangian analysis yields the small-amplitude dynami cs of the vortex and the condensate, directly determining the equations of motion of the coupled normal modes. As found previously from the Bogoliubov equations, there an two rigid dipole modes and one anomalous mode with a n egative frequency when seen in the nonrotating laboratory frame.