This paper reports the discovery of a new vortex phenomenon in superfluid . A single filament of quantized vortex line precesses as a solid body around a wire extending along the axis of a cylinder. The precession frequency equals the angular velocity of the apparatus at which the presence of a single quantum of circulation minimizes the system’s free energy. The period of precession is related to the circulation quantum and the dimensions of the apparatus. Thus a measurement of the precession period is an accurate determination of the quantum unit. We find κ=(1.020±0.03)h/2, where is the mass of the atom.
- Received 8 January 1992
- Published in the issue dated 2 March 1992
© 1992 The American Physical Society