Andreev Reflection in Superfluid 3He: A Probe for Quantum Turbulence

Andreev reflection, familiar in superconducting systems, shows a much more extensive set of behaviors in the p-wave condensate of superfluid 3He. We discuss the basic ideas of Andreev reflection in the superfluid and its various manifestations. The fact that the process displays almost perfect retroreflection allows us to exploit the remarkable properties of the phenomenon for characterizing the pure quantum turbulence that can exist in these condensates. Finally, we discuss Andreev-reflection “optics” as a means of visualizing this turbulence in real time through the vortex video camera.