Andreev reflection of quasiparticles by a vortex tangle in superfluid He-3-B?

We have made the surprising discovery that the thermal damping of a vibrati ng wire resonator in superfluid He-3-B at ultra low temperatures is conside rably depressed when a second wire in the vicinity is driven supercriticall y. The damping of a vibrating wire resonator at low velocities in the B-pha se arises from the scattering of quasiparticle excitations and has a temper ature dependence proportional to the Boltzmann factor exp(-Delta /kT) at lo w temperatures. At higher velocities (v > v(L)/3), the wire breaks Cooper p airs and emits a quasiparticle beam. At first sight it seems paradoxical th at heating the superfluid can reduce the quasiparticle flux: on a neighbour ing wire. We can only understand this on the basis that vorticity emitted b y the supercritical wire shields, via Andreev reflection, part of the backg round quasiparticle flux: from reaching the other wire. If this interpretat ion, is correct, these techniques will provide a sensitive probe of vortex dynamics in the ultra low temperature regime.