Phase-slip avalanches in the superflow of helium-4 through arrays of nano-apertures

Paul Goldbart, Department of Physics, University of Illinois at Urbana-Champaign

Helium-4 superflow through arrays of a few thousand nano-apertures involves phase slips in the superflow that lose their synchronicity under roughly 10 mK below the superfluid transition temperature. This synchronicity loss resembles the better-known loss of system-wide rupture events that randomness can produce in models of earthquakes and avalanches. A simple model, featuring a competition between randomness in the aperture critical velocities and coupling between aperture superflows, is consistent with observations and suggests ways of maintaining the potentially technologically useful feature of synchronous phase slippage.