Macroscopic quantum phenomena in superfluids and superconductors

In this paper I will discuss the common macroscopic quantum phenomena in the three superfluid systems known in condensed matter, the superconducting state of a metal, the superfluid phase of liquid⁴He, and the superfluid phases of liquid³He. The discussed phenomena will be persistent currents and their decay, critical velocities and critical magnetic fields, quantization of magnetic flux and of circulation, the two-dimensional flux and vortex lattices, and eventually the Josephson effects.Invited paper at the International Conference on Macroscopic Quantum Phenomena, Smolenice Castle, Czechoslovakia, September 18–22, 1989.