DC SUPERCURRENTS FROM RESONANT MIXING OF JOSEPHSON OSCILLATIONS IN A HE-3 WEAK-LINK

We have discovered that the de mass current through a superfluid He-3 weak link is substantially increased when the Josephson frequency matc hes the resonant frequency of a coupled mechanical oscillator. The phe nomenon is the result of homodyne mixing between the Josephson oscilla tions and the oscillating pressure held associated with the resonant s ystem. The measured sizes of the current enhancements are in excellent agreement with calculations based on this homodyne model. Similar obs ervations in superconducting junctions, in which microwave radiation c hanges the de electronic current, were used for the first confirmation of the dynamics of the superconducting Josephson effect.