Issues

A diverse class of physical systems—including superconductors, superfluid helium, lasers and quasi‐one‐dimensional conductors—derive their unusual properties from the macroscopic occupation of a single quantum state.

The notion that a quantum system's wovefunction may not return to its original phase after its parameters cycle slowly around a circuit had many precursors—in polarized light, radio waves, molecules, matrices and curved surfaces.

Theorists and experimenters find that small aggregates of metal atoms exhibit a shell structure like that of atomic nuclei. With this knowledge they hope to determine which properties define ‘metallic’ over the range from atom to bulk.