Scientific progress has become a collective process. No physicist can ever pretend that he has achieved something, that he had had a personal idea or made any original discovery independently of his colleagues. Recognizing this situation does not mean that it is impossible to identify the authors of scientific discoveries, but one should do it carefully. Instead, there is some tendency to attribute discoveries to single persons, an attitude which is not fair enough. Moreover, our prize tradition is certainly very nice, stimulating and generous, but it has some drawbacks: one is tempted to forget those among our colleagues who did not win. With these ideas in mind, I have found particularly interesting to inquire about the history of the discovery of superfluidity
As we shall see, I am not saying that Kapitza in 1978 or Landau in 1962 were awarded the Nobel prize for the discovery of superfluidity, nor criticiz ing this choice. In fact, for Kapitza it was “for his basic inventions and discoveries in the area of low-temperature physics” and for Landau “for his pioneering theories for condensed matter, especially liquid helium”. Further more, in the official presentation speech of Kapitza’s prize, it was mentioned that “The same discovery was made independently by Allen and Misener However, since superfluidity occupies a large part in the official presentation of their prizes, and since nobody else was recognized at that level for the discovery of superfluidity, there is a general tendency to forget that other great scientists have achieved major contributions to this discovery. It is this tendency which I wish to criticize. One example is the article Superfluidity in the Encyclopaedia Britannica, which starts with the sentence: “Super fluidity in helium-4 was discovered in 1938 by the Soviet physicist Pyotr Leonidovich Kapitsa .Another striking example is the presentation speech of the 1996 Nobel prize to Lee, Osheroff, and Richardson, where one reads it was not until the end of the 1930s that PjotrKapitsa (Nobel Prize 1978) discovered experimentally the phenomenon of superfluidity in helium-4” (no mention of Allen and Misener this time). As we shall see below, Landau also considered that superfluidity had been discovered by Kapitza only and he must have had a strong influence on the opinion of his colleagues; for example E.M. Lifshitz wrote:“I have been asked by the editors of Scientific American to give a short survey of what has been learned about superfluid ity, first discovered in 1937 by Peter L. Kapitza at the Institute for Physical Problems in Moscow”.
As for the attribution of the theoretical understand ing of superfluidity to Landau, the situation is more subtle, especially since the discovery of superfluidity in alkali gases
where the existence of Bose Einstein condensation is obvious, but it is somewhat similar. For example R. Donnelly wrote
“Finally, there was no great scientific leader active in understanding liquid helium in the early days. When Kapitza and the great theoretical physicist Landau, followed by physicists such as Fritz London Lars Onsager, Richard Feynman and other greats, came on board, there was a tremendous surge of excitement, which lasted for many years and helped bring the subject to its present state of understanding”. I wish to explain that the contributions by London and by Tisza, which were published three >years before Landau’s, were major breakthroughs in the understanding of superfluidity. Fortunately, my opinion seems to be shared by several other nobr>authors
Some aspects of this issue have already been considered by several au thors, especially by R. Donnelly in the article mentioned above
When trying to go deeper into it, I distinguished three more precise questions 1- Who made the experimental discovery 2- Who has initiated its theoretical understanding ? 3- How did all this happen in a period (the late 1930’s and early 1940’s where the world was torn apart by conflicts and wars One usually considers that superfluidity was discovered in December 1937, the submission date of the two articles on the flow of liquid helium which appeared side by side in Nature on January 8, 1938. On page 74 was the article by P. Kapitza
Pjotr Leonidovich Kapitsa was born in Kronstadt, near Leningrad, on the 9th July 1894, son of Leonid Petrovich Kapitsa, military engineer, and Olga Ieronimovna née Stebnitskaia, working in high education and folklore research.
Kapitsa began his scientific career in A.F. Ioffe's section of the Electromechanics Department of the Petrograd Polytechnical Institute, completing his studies in 1918. Here, jointly with N.N. Semenov, he proposed a method for determining the magnetic moment of an atom interacting with an inhomogeneous magnetic field. This method was later used in the celebrated Stern-Gerlach experiments.