Precession of vortices in dilute Bose-Einstein condensates at finite temperature

We demonstrate that the precessional frequencies of vortices in Bose-Einstein condensates (BECs) are determined by a conservation law and not by the lowest-lying excitation energy mode. We determine the precessional frequency for a single off-axis vortex and vortex lattices in BECs using the continuity equation and solve this self-consistently with the time-independent Hartree-Fock-Bogoliubov equations in the rotating frame. We find agreement with zero-temperature calculations (Bogoliubov approximation) and a smooth variation in the precession frequency as the temperature is increased. Time-dependent solutions confirm the validity of these predictions.