William Zimmermann

My research area is the experimental study of superfluidity in liquid helium. In particular, I have been studying the role of quantum vortices in the onset of dissipation of superfluid flow through micron and submicron apertures in thin films. Of particular interest are the processes by which vortices are nucleated at the critical velocity and the subsequent hydrodynamic evolution of the vortices. Use is made of a sensitive hydrodynamic resonator in which oscillatory flow through the aperture takes place. Behaviour in superfluid helium analogous to that due to the Josephson effect in superconductors is also under study. My research also involves the development of techniques to fabricate the apertures used in this work.