Whereas the superfluidity of the helium isotope 4He-the anomalous behaviour it shows in the liquid state-had been known for several decades, the lighter isotope 3He had shown no evidence of unusual behaviour at extremely low temperatures until 1972, when three new phases of this isotope were discovered. These phases combine most of the interesting features of superfluid 4He, of superconductors, and of liquid crystals. The author reviews various theories of these effects.
ASJC Scopus subject areas
- History and Philosophy of Science