The rotation of liquid helium II

Abstract

The foundations of Landau's theory have been considerably strengthened by Feynman's deduction of the phononroton excitation spectrum and by inelastic scattering of cold neutrons. A development for the interpretation of the condition curl V/sub s/ = 0 by a rather less restrictive condition which is interpreted as meaning that curl V/sub s/ = 0 almost everywhere in the liquid. There may be certain lines in the liquid on which the velocity is singular. The consequences of the circulation around these quantized vortex lines are explored. Rotation, here, is defined as flow in which circulation of the superfluid exists. A definite theoretical viewpoint is adopted for the discussion and is used to give a unified account of as many experimental facts as possible. Various types of flow are discussed in order of increasing complexity, proceeding from irrotational circulation through macroscopically uniform rotation to turbulence. Though many of the arguments and conclusions presented may subsequently be proven wrong, Feymnan's basic idea of quantized vortex lines can explain so many diverse experimental results that one can be confident that it will find a permanent place in the theoretical description of liquid helium II. (B.O.G.)