Onsager's Quantization of Circulation in Superfluid Helium

First ideas about quantized circulation and vortices

The idea of quantized circulation in superfluid helium was first put forth to students and colleagues at Yale University by Lars Onsager beginning about 1946. Onsager enjoyed the drama of an important scientific announcement and made public his discovery in a remark following a paper by Gorter on the two-fluid model at the Conference on Statistical Mechanics in Florence in 1949. He said, in part, "Thus the well-known invariant called the hydrodynamic circulation is quantized; the quantum of circulation is h/m . In the case of cylindrical symmetry, the angular momentum per particle is a multiple of ℏ"¹. Enormous ramifications of this single remark have come about and it has been observed more than once that the ratio of scientific insight to length of announcement must be a record in the history of science…