Pyotr Leonidovich Kapitsa
1894–1984, Kronstadt, Russian Empire, Moscow, Soviet Union
Soviet physicist who discovered the superfluidity of liquid helium-4 and pioneered low-temperature and high-magnetic-field techniques.
Sent by the Soviet government to Cambridge in 1921, Kapitsa became Rutherford's protégé, building the Cavendish's high-field magnet lab and a novel liquefier that made liquid helium cheaply available. Detained on a 1934 visit to Moscow, he recreated his laboratory at the new Institute for Physical Problems, where in 1937–38 he found that helium II flows through capillaries with zero viscosity — the discovery of superfluidity.
Nobel-winning work
Kapitsa's 1978 Nobel Prize honored 'basic inventions and discoveries in the area of low-temperature physics'. Cooling helium below the 2.17 K lambda point, he observed in January 1938 that the liquid passed through the finest capillaries with no measurable pressure drop — viscosity effectively zero.
Published alongside Allen and Misener's independent measurement, the discovery of superfluidity opened the study of quantum fluids: Landau's two-fluid theory, quantized vortices and ultimately Bose-Einstein condensation in atomic gases all descend from Kapitsa's helium-II experiments.
Workplaces: Cavendish Laboratory, University of Cambridge, Institute for Physical Problems, Moscow
Russia