The Love of His Life

The solid state physics community is electrified when Bardeen, Cooper, and Schrieffer (BCS) announce their discovery of a microscopic model capable of explaining the phenomenon of superconductivity,which is observed in some metals at very low temperature. To understand Anderson’s contributions to this subject, this chapter begins with the phenomenology of superconductivity and then sketches a few key aspects of many-electron theory, including the concepts of collective excitations and quasiparticles. Anderson explains the apparent lack of gauge invariance of the BCS approach and then uses a sophisticated approximation to study the excited states of a superconductor. He travels to Russia where his theory gains the approval of Lev Landau and he demonstrates how to analyze so-called dirty superconductors. He collaborates indirectly with Robert Schrieffer to generalize the BCS model into a full-blown theory capable of describing any material where the electron-phonon interaction drives superconductivity.