‎"HEISENBERG, WERNER.‎
‎Bermerkung zur Diracschen Theorie des Positrons (+) Folgerungen aus der Diracschen Theorie des Positrons. - [EULER-HEISENBERG LAGRANGIAN]‎

‎Berlin, Springer, 1934 & 1936. 8vo. In two contemporary halv cloth with gilt lettering to spine. In ""Zeitschrift für Physik"", Bd. 90, 1934 & Bd. 98, 1936. Entire volumes offered. Stamp to front free end-paper and titlepage, otherwise fine. Pp. 209-23" Pp. 714-32. [Entire volume: VIII, 835 pp." VIII, 794 pp.].‎

Reference : 49191

‎First appearance of Heisenberg and Euler's important papers in which they were the first to be able to show that Paul Dirac's introduction of the positron opens the possibility that photons in electron-positron pair production scatter with each other. Here they also presented the Euler-Heisenberg Lagrangian which describes the non-linear dynamics of electromagnetic fields in vacuum. It takes into account vacuum polarization to one loop, and it is valid for electromagnetic fields that change slowly compared to the inverse electron mass. ""Heisenberg preferred to continue the search for a consistent quantum physics, much of which was pursued by his assistant Hans Euler discovered that nonlinear interactions in positron theory, which yielded photonphoton scattering, could be represented by treating the electron as possessing a minimum size, below which the interferences predominated."" (DSB).Cassidy 1934a, 1936a.‎