Quantum Dispersion Theory in the Early 20s

Heisenberg’s breakthrough to matrix mechanics was directly stimulated by studies of interaction of quantized material systems with electromagnetic radiation which came to a head in the Kramers-Heisenberg paper on dispersion theory in January 1925. In this talk, we will review the important contributions of Kramers, van Vleck, and Born to this subject. Important results from classical physics will also be reviewed: the hope is that the presentation should be as far as possible comprehensible to an audience familiar with basic classical mechanics (including Hamilton’s equations), electromagnetic theory (in particular, dipole radiation), and elementary quantum theory.