Development of the Theory of Superfluidity in the USSR: Some Remarks

Abstract

Superconductivity was discovered in 1911 by Kamerling Onnes in a single stroke. On the other hand, the discovery of superfluidity took nearly 30 years. In the same year, 1911, Kamerling Onnes observed some anomaly in liquid helium, connected, in fact, with the lambda-transition and superfluidity. But, only in 1938 was superfluidity, as frictionless flow, discovered, independently by Kapitza and by Allen and Misener. By 1941 a rather clear understanding of superfluidity was achieved in the works of Landau¹ and Kapitza. Later, Landau together with his collaborators, developed the theory further. Landau’s two-fluid theory of superfluidity is quite successful. This theory, however, is applicable everywhere except in the vicinity of the lambda-point, because the ρ_s-density of the superfluid part of the HeII, is supposed in [1], to be some given function of other thermodynamical variables, while near the lamda-point we must introduce the order parameter, which is determined by some equations.