On Superconductivity and Superfluidity (What I Have and Have Not Managed to Do), as well as on the ‘Physical Minimum’ at the Beginning of the 21st Century

The question of thermeolectric effects in superconductors is still a particular problem, which evidently emerges only in the presence of a temperature gradient. The well-known Londons theory yielded much, and is widley employed under certain conditions even nowadays, but is absolutely insufficient and has to be generalized. This problem was solved in the psi-theory of superconductivity by V.L. Ginzburg and L.D. Landau. Together they developed a phenomenological theory of superconductivity in the late 1940s. This theory proposes that those electrons that contribute to superconduction form a superfluid. The superconductor is described by a complex function psi called the order parameter, and /psi/ indicates the fraction of electrons that has condensed into a superfluid. In his Nobel lecture V. L. Ginzburg also gives a 'list' of top problems in contemporary physics. Acquaintance with all subjects included in this 'list' is what he calls the 'physical minimum'.