COUPLING MECHANISMS FOR DAMPED VORTEX MOTION IN SUPERFLUIDS

We investigate different dissipative dynamics for a vortex line immers ed into a superfluid where density fluctuations have been excited. For this sake, we consider various linear coupling models where the vorte x interacts with the quasiparticles of the normal fluid through its co ordinate or momentum. We can unambiguously show that one and only one combination of these variables leads to damped evolution in agreement with the phenomenological descriptions.