A Trustworthy and Popular “Helpdesk”

Abstract

Källén’s scientific honesty and his exceptional faculty for fast analysis made him an ideal advisor for many scientists. They knew that they could trust him and would send their manuscripts to him, for his comments, before sending them to journals. As was noted before, Pauli recognized this speciality of Källén and wrote about it, for example, to Heisenberg: If you wish to get an answer from letters to Copenhagen, I give you the practical advice not to write to Møller or Glaser but to write to Källén. To wit, he gladly writes long letters (especially when he believes he can prove you wrong, which is almost always the case).

Young people would ask him all sorts of questions, such as how does a maser work, where do angle – angular momentum uncertainty relations come from, etc. More senior theorists would consult him primarily about the intricacies of quantum electrodynamics and quantum field theory.