In August 1945, with the war ended, Bohr returned to Denmark, where he resumed his university education, graduating with a master's degree in 1946, with a thesis concerned with some aspects of atomic stopping power problems.[3] In early 1948, Bohr became a member of the Institute for Advanced Study in Princeton, New Jersey.[14] While paying a visit to Columbia University, he met Isidor Isaac Rabi, who sparked an interest in recent discoveries related to the hyperfine structure of deuterium. This led to Bohr becoming a visiting fellow at Columbia from January 1949 to August 1950.[3][15] While in the United States, Bohr married Marietta Soffer on 11 March 1950. They had three children: Vilhelm, Tomas and Margrethe.[15][16]