Some Reflections on Arnold Sommerfeld—Theoretical Physicist, Teacher, Influencer [Historically Speaking]

Arnold Sommerfeld is one of the most influential theoretical physicists of all times. His contributions to electromagnetics comprise mathematical theories of diffraction and fundamental work on wave propagation above planar ground, leading to the concept of Sommerfeld integral representations. Probably even more recognized are his contributions to the theory of atoms and to the development of quantum physics. In his role as educator and teacher, Sommerfeld’s performance is unprecedented—four of his doctoral graduates and three of his postdocs are recipients of a Nobel Prize in physics or chemistry; one even received an additional Nobel Peace Prize. In his role as an influencer, Sommerfeld was instrumental for the development of theoretical physics in the first half of the 20th century, where his way of doing physics influenced scientists all over the world, and dozens of his students and postdocs came into leadership positions in universities, companies, and other institutions. The goal of this article is to highlight some cornerstones and developments in the life and career of Arnold Sommerfeld and to give some insight into his way of doing science and education, where the focus is on electromagnetics and wave propagation.