The flow of superfluid ⁴He through submicron apertures: Phase slip and critical velocities due to quantum vortex motion

Abstract

A review is given of recent experimental studies on the onset of dissipation in the flow of superfluid ⁴He through submicron-size apertures. These studies have revealed the occurrence of energy loss in discrete events. The interpretation of these events in terms of the motion of individual quantum vortices across the flow is discussed.