Kramers–Heisenberg formula Kramers–Heisenberg formula The Kramers–Heisenberg dispersion formula is an expression for the cross section for scattering of a photon by an atomic electron. It was derived before the advent of quantum mechanics by Hendrik Kramers and Werner Heisenberg in 1925, based on the correspondence principle applied to the classical dispersion formula for light. The quantum mechanical derivation was given by Paul Dirac in 1927. The Kramers–Heisenberg formula was an important achievement when it was published, explaining the notion of "negative absorption" (stimulated emission), the Thomas–Reiche–Kuhn sum rule, and inelastic scattering — where the energy of the scattered photon may be larger
Martin Heisenberg Martin Heisenberg Martin Heisenberg (born 7 August 1940) is a German neurobiologist and geneticist. Before his retirement in 2008, he held the professorial chair for genetics and neurobiology at the Bio Centre of the University of Würzburg. Since then, he continues his research with a senior professorship at the Rudolf Virchow Center of the University of Würzburg. Heisenberg studied chemistry and molecular biology in Munich, Tübingen and Pasadena. In 1975 he became Professor of genetics and neurobiology at the University of Würzburg. Heisenberg's work has focused on the neurogenetics of Drosophila (the fruit fly), with the aim of investigating the