THE DISCOVERY OF SUPERFLUIDITY

KAPITZA, P (+) J. F. ALLEN (+) A. D. MISENE

Viscosity of liquid Helium below the lambda-point [Kapitza] (+) Flow of liquid Helium II [J. F. Allen & A. D. Misener] [The volume also contain the following papers: New phenomena connected with heat flow in liquid Helium II [J. F. Allen & H. Jones] (+) The [lambda]-phenomenon of liquid Helium and the Bose-Einstein degeneracy [F. London] (+) Transfer of Helium II on glass [J. G. Daunt & K. Mendelssohn] (+) Experiments with liquid Helium II [A. K. Kikoin & B. G. Lasarew] (+) Transport phenomena in Helium II [L. Tisza]]

London, Macmillian and Co, 1938.

Royal8vo. In contemporary half cloth with white paper title-label pasted on to spine. In: "Nature", January - June, 1939, Vol. 141, entire volume offered. Stamp to front free end-paper and title-page, otherwise fine and clean copy. P. 74; P. 75. [Entire volume: LXIV, 1156 pp.].

First publication of these two seminal papers which constitutes one of the most significant discoveries in 20th century physics. It ushered a golden period of low-temperature physics and created a new research field within physics which was later to be called quantum liquids. Both paper described a hitherto unknown state of matter: superfluidity of matter. The two discoveries were made independently, Kapitza's paper superseding Allen and Misener's by two weeks. Both studies reported that liquid helium flowed with almost no measurable viscosity below the transition temperature of 2.18 K.

"Although the discovery of superfluidity stands as one of the most significant in physics in the 20th century, it was to be 40 years before the Royal Swedish Academy of Sciences honoured this seminal discovery with a Nobel prize - an exceptionally long interval. In 1978 Kapitza, by then 84, was given half of that year's Nobel Prize for Physics with a somewhat vague citation reading "for his basic inventions and discoveries in the area of low-temperature physics". The other half did not go to Allen and Misener. Today, science popularizers generally give sole credit for the discovery of superfluidity to Kapitza." (Physics world, University of Toronto.).

"Kapitza observed that He II flowed between two closely spaced parallel plates extremely rapidly compared to He I, for the same pressure difference. This result, published in Nature on 8 January 1938, showed unambiguously that here was a new and mysterious kind of liquid - one with almost no viscosity. On the page facing Kapitza's one-page paper was another by the young Canadian physicists Jack Allen and Donald Misener, with essentially equivalent results on helium flow on long capillary tubes. It was submitted two weeks after Kapitza's, but both papers are the standard reference for the discovery of superfluidity". (Griffin, A Century of Nature, 2003, p. 52).

While investigating the thermal conductivity of liquid helium, Kapitsa measured the flow as the fluid flows through a gap between two discs into a surrounding bath. Above the lambda point, there was little flow, but below the lambda temperature, the liquid flowed with such great ease that Kapitsa drew an analogy with superconductors. It was a liquid of zero viscosity. He discovered the phenomenon in 1937 and published a paper about it in Nature in January 1938. He wrote: "The helium below the lambda point enters a special state that might be called a ‘superfluid.’" (DSB).

Today the theory behind superfluidity is widely used within a broad variety of different subject such as spectroscopic and in high-precision devices as gyroscopes which allow the measurement of some theoretically predicted gravitational effects.
In 1999, a type of superfluid was used to trap light and greatly reduce its speed. Light was passed through a Bose-Einstein condensed gas of sodium (superfluid) and found to be slowed to 17 m/s from its normal speed of 299,792,458 metres per second.

Brandt, The Harvest of a Century, Pp. 254-7.

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