Known to exist for just two substances, in one, it is explained by p-wave p
Known to exist for just two substances, in one, it is explained by p-wave pairing of the [*] fermionic atoms.  In the other, its onset is marked by a characteristic shape in the specific heat curve at the lambda point, 2.17  Kelvins For 10 points—name this phenomenon, in which liquid helium-3 and helium-4 have almost zero viscosity..
Known to exist for just two substances, in one, it is explained by p-wave pairing of the [*] fermionic atoms.  
superfluidity or superfluid(s) or superfluid state