摘要：

An intuitive picture of pair breaking by a vibrating wire is developed, which makes dear how quasi-particles can escape from the wire at critical velocities below the Landau critical velocity ν L. Assuming strong gap suppression at the wire surface, a critical velocity of ν ∗ = ν L 5 is obtained, for ideal dipole flow around a wire of circular cross-section. In addition, a further transition to enhanced quasi-particle emission is predicted to occur at a velocity ν 1 ∗ = ν L 3 More generally, for non-dipole flow, ν ∗ = ν L (1 + 2α 1) and ν 1 ∗ = solν L (1 + α l where at α l characterizes the local superflow near the surface of the wire.

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