After the war, in 1945, he worked a lecturer at the Lublin Polytechnic. In 1946 he moved back to Warsaw, where he took a position at the University of Warsaw and where, in that year he got his magisterium in theoretical physics under Jan Blaton. He received a scholarship of Ministry of Education and defended his doctoral thesis in 1947. In 1948 he was hired as an adjunct at the Mikolaj Kopernik University in Toruń. He spent the next year at the University of Birmingham.