The Experimental Observation of a Superfluid Gyroscope in a dilute Bose   Condensed Gas
  We have observed a superfluid gyroscope effect in a dilute gas Bose-Einstein condensate. A condensate with a vortex possesses a single quantum of angular momentum and this causes the plane of oscillation of the scissors mode to precess around the vortex line. We have measured the precession rate of the scissors oscillation. From this we deduced the angular momentum associated with the vortex line and found a value close to $\hbar$ per particle, as predicted for a superfluid. 
E. Hodby, S.A. Hopkins, G. Hechenblaikner, N.L. Smith and C.J. Foot