Neutron scattering by flux-line lattices in clean, type II superconductors

The scattering of neutrons by a clean, type II superconductor in the mixed state is studied, using a quantized hydrodynamic theory for the superfluid vortex lattice. If the scattering amplitude is expanded in the number of quanta of vortex waves emitted or absorbed, the resulting inelastic cross section diverges at long wavelengths. Inclusion of inelastic effects to all orders removes this unphysical singularity and yields a differential cross section which differs only slightly from that predicted for elastic scattering. (U.S.)