Abstract
This article reviews some of the experimental work on the Josephson effects. These effectsoccur in both superconductivity and superfluidity. In superconductivity they are found when two superconductors are separated by a thin insulating barrier (∼ 10−9 m thick), or connected by a weak link of metal. A supercurrent can flow between the superconductors, and electromagnetic and magnetic fields can interact with this supercurrent. The interactions demonstrate quantum effects in a particularly striking way, have led to a better understanding of the superconducting state, and have also found some interesting applications.