Nonequilibrium Nature of the Superfluid State

Abstract

We show that the result of the preceding paper is directly applicable to liquid helium, i.e., no superfluid state can exist in liquid helium under conditions of thermodynamic equilibrium. The observed superfluid properties of liquid helium must therefore be due to a nonequilibrium (metastable) superfluid state. Previous theoretical arguments for equilibrium superfluidity are examined, and an experimental test of nonequilibrium superfluidity is suggested.