Niels Bohr & Werner Heisenberg
Bohr and Werner Heisenberg enjoyed a strong mentor/protÃ©gÃ© relationship up to the onset of World War II. Bohr became aware of Heisenberg's talent during a lecture Heisenberg gave in GÃ¶ttingen in 1922. During the mid-1920s, Heisenberg worked with Bohr at the institute in Copenhagen. Heisenberg, like most of Bohr's assistants, learned Danish. Heisenberg's uncertainty principle was developed during this period, as was Bohr's complementarity principle.
By the time of World War II, the relationship became strained; this was in part because Bohr, who was of half-Jewish ancestry, remained in occupied Denmark, while Heisenberg remained in Germany and became head of the German nuclear effort. Heisenberg made a famous visit to Bohr in September 1941 and during a private moment it seems that he began to address nuclear energy and morality as well as the war. Neither Bohr nor Heisenberg spoke about it in any detail or left written records of this part of the meeting and they were alone and outside. Bohr seems to have reacted by terminating that conversation abruptly while not giving Heisenberg hints in any direction.
While some suggest that the relationship became strained at this meeting, other evidence shows that the level of contact had been reduced considerably for some time already. Heisenberg suggested that the fracture occurred later. In correspondence to his wife, Heisenberg described the final visit of the trip: "Today I was once more, with WeizsÃ¤cker, at Bohr's. In many ways this was especially nice, the conversation revolved for a large part of the evening around purely human concerns, Bohr was reading aloud, I played a Mozart Sonata (A-Major)." Ivan Supek, one of Heisenberg's students and friends, claimed that the main figure of the meeting was actually WeizsÃ¤cker who tried to persuade Bohr to mediate peace between Great Britain and Germany.