title: Vortex precession in Bose-Einstein condensates: observations with filled and empty cores.
abstract: We have observed and characterized the dynamics of singly quantized vortices in dilute-gas Bose-Einstein condensates. Our condensates are produced in a superposition of two internal states of 87Rb, with one state supporting a vortex and the other filling the vortex core. Subsequently, the state filling the core can be partially or completely removed, reducing the radius of the core by as much as a factor of 13, all the way down to its bare value of the healing length. The corresponding superfluid rotation rates, evaluated at the core radius, vary by a factor of 150, but the precession frequency of the vortex core about the condensate axis changes by only a factor of 2.
authors.affiliation: JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA.
authors.forename: B P
authors.initials: BP
authors.lastname: Anderson
authors.forename: P C
authors.initials: PC
authors.lastname: Haljan
authors.forename: C E
authors.initials: CE
authors.lastname: Wieman
authors.forename: E A
authors.initials: EA
authors.lastname: Cornell