The defining property of superfluids is their ability to flow without friction, at least in some regimes. In fact, the presence of quantized vortices can open a new dissipative channel that leads to hydrodynamic friction. Understanding this mechanism is an important ingredient to model neutron star phenomenology, like pulsar glitches, oscillation modes damping, cooling of old pulsars and, possibly, timing noise. Recent simulations of vortex motion in a disordered environment allowed to test some qualitative features that are expected for this kind of friction: the main results and their relevance for neutron star dynamics will be discussed.
Michael Urban
