(*) Rollin films exhibit the Onnes effect as a consequence of this phenomenon.
For substances exhibiting this phenomenon, a criterion stating that the Doppler-shifted kinetic energy of certain quasiparticles must be positive gives a critical velocity above which this behavior cannot occur. Fluctuations in phonon density in substances exhibiting this phenomenon allow extremely fast wave-like heat transfer, a phenomenon known as second sound. (*) Rollin films exhibit the Onnes effect as a consequence of this phenomenon. This phenomenon can be used to separate mixtures of helium-3 and helium-4 since they undergo a certain phase transition at different temperatures. For 10 points, name this phenomenon in which a cooled liquid can creep out of its container as it loses all resistance to flow.
For substances exhibiting this phenomenon, a criterion stating that the Doppler-shifted kinetic energy of certain quasiparticles must be positive gives a critical velocity above which this behavior cannot occur.
superfluidity