Scattering of First Sound by Superfluid Vortices

The simplest interaction between sound and quantized superfluid vortices is investigated both analytically in the Born approximation and numerically, using the nonlinear Schr\"odinger equation. Compared with the scattering by a classical vortex, the quantum result reflects the structure of the vortex core and has an extra phase shift. The order of magnitude of the effects suggests possible experiments in rotating superfluid helium.