Arnold Johannes Wilhelm Sommerfeld 1868-1951

Abstract Arnold Sommerfeld was one of the most distinguished representatives of the transition period between classical and modern theoretical physics. The work of his youth was still firmly anchored in the conceptions of the nineteenth century; but when in the first decennium of the century the flood of new discoveries, experimental and theoretical, broke the dams of tradition, he became a leader of the new movement, and in combining the two ways of thinking he exerted a powerful influence on the younger generation. This combination of a classical mind, to whom clarity of conception and mathematical rigour are essential, with the adventurous spirit of a pioneer, are the roots of his scientific success, while his exceptional gift of communicating his ideas by . spoken and written word made him a great teacher. I was not a pupil of Sommerfeld, but met him for the first time in later life. Yet from this moment our friendship was firmly established. The picture of his personality which I carry with me and shall try to describe in these pages is drawn on this background of personal contact. I have further at my disposal a charming autobiographic sketch, which he wrote in 1919 for the Academy of Vienna, with an appendix probably added in 1950, and several obituary articles, of which those written by Heisenberg and von Laue are the most remarkable.1 Arnold Johannes Wilhelm Sommerfeld was born in Königsberg, East Prussia, on 5 December 1868. His father, Dr Franz Sommerfeld, was a medical practitioner devoted to science and a passionate collector of natural objects like minerals, amber, shells, beetles, etc. Königsberg—now a Russian town with another name—was the capital and coronation city of the Prussian kings and had developed a specific atmosphere of erudition and culture. It was Immanuel Kant’s place of birth and permanent home.