Some remarks on the theory of superconductivity

SUPERCONDUCTIVITY THEORY has been approached in several ways. The most direct but also the most difficult is the attempt to derive all facts from a detailed microscopic theory, and the most significant steps in this direction have been made since 1957 through the theory of John Bardeen, Leon N. Cooper and J. Robert Schreiffer. Another approach, less fundamental but often very instructive, is based on suitably chosen simple models, of which the degenerate ideal Bose gas, suggested by M. R. Schafroth in 1955, has proven to be particularly useful.