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
Max Planck Institute for Physics Max Planck Institute for Physics The Max Planck Institute for Physics (MPP) is a physics institute in Munich, Germany that specializes in high energy physics and astroparticle physics. It is part of the Max-Planck-Gesellschaft and is also known as the Werner Heisenberg Institute, after its first director in its current location. The founding of the institute traces back to 1914, as an idea from Fritz Haber, Walther Nernst, Max Planck, Emil Warburg, Heinrich Rubens. On October 1, 1917, the institute was officially founded in Berlin as "Kaiser-Wilhelm-Institut für Physik" (KWIP, Kaiser Wilhelm Institute for Physics) with Albert Einstein as the