The Seeds of Dispersion

Abstract The Feynman diagrams' dispersion in pictorial form, with their attendant dispersion in calculational roles, may be derived from at least two sources. In the first place, the diagrams' original progenitors—Feynman and Dyson—disagreed about the diagrams' proper forms, uses, and meanings. The split between Feynman and Dyson provided one key ingredient for the diagrams' later scattered order. The other crucial factor came from the failure of Feynman's and Dyson's original diagrammatic techniques when physicists tried to tackle the behavior of particles beyond the familiar electron and photon. Theorists such as Paul Matthews, Jack Steinberger, and Abraham Pais tinkered with the form of their diagrams, all in an effort to craft their diagrams to better suit their new purposes. Eventually, between the Feynman–Dyson split and the failure of perturbative approaches for treating nuclear forces, Feynman diagrams' pictorial forms and calculational roles became more and more differentiated.