A Brief Background to Källén’s Scientific Publications

Abstract

Källén was sent to “Pauli’s Court”, just like a number of other talented young men those days, to attend his summer term lectures for about three months during April–July 1949. After returning home, he finished his first paper, on a work that he had started during his stay in Zürich. Pauli wanted Källén to publish his work in the Swiss journal Helvetica Physica Acta. Källén didn’t know whether it was allowed for a Swede, funded by Sweden, to publish in a foreign journal. The formal rules were important to him and he asked for permission to do so. It was granted. His paper [1] “Higher Approximations in the External Field for the Problem of Vacuum Polarization” was received by Helv. Phys. Acta on 13 August 1949. His affiliation is given as Swiss Federal Institute of Technology, Zürich, as well as at leave from: Department of Mechanics and Mathematical Physics, University of Lund, Sweden.