(1898–1968), physicist. The son of a shoeshop owner, Leopold Infeld was born in Kraków. He studied at the Jagiellonian University with Władysław Natanson between 1916 and 1921 and was later able to study briefly in Berlin. Infeld was an assistant to the chair of theoretical physics at the Jagiellonian University between 1921 and 1924, when he went again to Berlin, and at the Jan Kazimierz University in Lwów from 1932, where until 1934 he held the position of docent (lecturer).
Because of antisemitism, Infeld could never hold a permanent academic post in Poland. Instead, he eked out a living between his various appointments by teaching. He taught physics at the Jewish gymnasium in Konin in 1921–1922, and between 1924 and 1930 at the Zofia Kalecka gymnasium in Warsaw. During this period he was also an official at the Jewish School Teachers Union. While in Berlin he met Albert Einstein, with whom he remained in contact. He also encountered a number of German Marxists and was strengthened in his generally left-wing view of the world, although he was not an engaged Communist.
In 1936, despairing of finding an academic position in Poland, Infeld immigrated to the United States, where between 1936 and 1938 he was an associate professor at the Institute of Advanced Study at Princeton. He then became a professor of physics at the University of Toronto. After the war, he publicly declared his opposition to atomic weapons. He was accused of passing atomic secrets to the Soviets, a charge that he always denied. The defection to Poland of a Communist Jewish member of parliament from Montreal, Fred Rose, made Infeld’s position still more difficult, as did his visit to Poland in 1949. In 1950, he decided to move to that country secretly, where he was immediately appointed professor of physics at the University of Warsaw and also subsequently obtained a position at the Polish Academy of Sciences. He remained politically active after his move to Poland and was one of the founders of the Pugwash group of scientists.
Infeld’s last years were darkened by growing political oppression and by antisemitism of the end of the Gomułka era in 1964. He was one of a group of 34 leading Polish intellectuals who protested government censorship. He died before the devastating effect of anti-Jewish purges unleashed on “anti-Zionist” grounds after the Israeli victory in the Six-Day War largely affected his attempts to rebuild Polish physics.
Infeld’s main interests lay in the theory of relativity (in which he collaborated with Einstein), equations of motion, unitary field theory, and quantum mechanics. He published widely on these topics and also wrote a number of books in which he attempted to popularize the principles of modern science.
Leopold Infeld, Quest, the Evolution of a Scientist (London and New York, 1941); Lewis Pyenson, “Introduction” in Why I Left Canada: Reflections on Science and Politics, by Leopold Infeld (Montreal, 1978); Theo Richmond, Konin: A Quest (London, 1995).