Quasiparticle Damping of Surface Waves in Superfluid He and He
arXiv:1410.4071 · doi:10.1103/PhysRevB.90.224502
Abstract
Oscillations on free surface of superfluids at the inviscid limit are damped by quasiparticle scattering. We have studied this effect in both superfluids He and He deep below the respective critical temperatures. Surface oscillators offer several benefits over immersed mechanical oscillators traditionally used for similar purposes. Damping is modeled as specular scattering of ballistic quasiparticles from the moving free surface. The model is in reasonable agreement with our measurements for superfluid He but significant deviation is found for He.