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

Research output: Contribution to Journal/MagazineJournal articlepeer-review

<mark>Journal publication date</mark>07/2000
<mark>Journal</mark>Journal of Low Temperature Physics
Issue number5-6
Number of pages6
Pages (from-to)393-398
Publication StatusPublished
<mark>Original language</mark>English


We have made the surprising discovery that the thermal damping of a vibrating wire resonator in superfluid He-3-B at ultra low temperatures is considerably depressed when a second wire in the vicinity is driven supercritically. The damping of a vibrating wire resonator at low velocities in the B-phase arises from the scattering of quasiparticle excitations and has a temperature dependence proportional to the Boltzmann factor exp(-Delta /kT) at low temperatures. At higher velocities (v > v(L)/3), the wire breaks Cooper pairs and emits a quasiparticle beam. At first sight it seems paradoxical that heating the superfluid can reduce the quasiparticle flux: on a neighbouring wire. We can only understand this on the basis that vorticity emitted by the supercritical wire shields, via Andreev reflection, part of the background quasiparticle flux: from reaching the other wire. If this interpretation, is correct, these techniques will provide a sensitive probe of vortex dynamics in the ultra low temperature regime.