Consequences of Brian Josephson’s Theoretical Discovery

Theoretical discovery of Josephson effects has beneficial consequences for science and economy, and in the future promises more benefits for public health. The strongest impact thus far has the use of Josephson devices and circuits in many areas of science and in geophysical prospecting for minerals. I highlight a few examples of present and future benefits.

Theory of Andreev bound states in S-F-S junctions and S-F proximity devices

Andreev bound states are an expression of quantum coherence between particles and holes in hybrid structures composed of superconducting and non-superconducting metallic parts. Their spectrum carries important information on the nature of the pairing, and determines the current in Josephson devices. Here, I focus on Andreev bound states in systems involving superconductors and ferromagnets with strong spin-polarization. I provide a general framework for non-local Andreev phenomena in such structures in terms of coherence functions, and show how the latter link wave function and Green-function based theories. This article is part of the theme issue ‘Andreev bound states’.