Dynamics of a single vortex line in a Bose-Einstein condensate

We study experimentally the line of a single vortex in a rotating prolate Bose-Einstein condensate confined in a harmonic potential. In agreement with predictions, we find that the vortex line is in most cases curved at the ends. We also present measurements of the quadrupole oscillation of the condensate in the presence of a single vortex. A theoretical treatment to account for the short time and long time behaviours of these modes is developed. Finally, we use these measurements to infer the angular momentum per particle and relate it to the shape of the vortex line.