Superpositions of Degenerate Quantum States: Preparation and Detection in Atomic Beams

Abstract Coherent superpositions of quantum states play an increasingly significant part of contemporary quantum technology. We here review examples of the preparation and analysis of superpositions of degenerate quantum states created by passing beams of atoms across laser beams. Following a summary of the basic theory underlying the creation of such superpositions through coherent excitation by laser pulses we offer specific examples of schemes that have created such superpositions. We then discuss methods whereby laser pulses can be used to measure the characteristics of a given superposition. We illustrate these techniques with examples of manipulation of degenerate states of metastable neon atoms in an atomic beam. We conclude with a discussion of various extensions and applications of these principles.