an "unconvincing claim" by Teller that he was a "covert dissenter" to the use of the bomb. In his 2001 Memoirs, Teller claims that he did lobby Oppenheimer, but that Oppenheimer had convinced him that he should take no action and that the scientists should leave military questions in the hands of the military; Teller claims he was not aware that Oppenheimer and other scientists were being consulted as to the actual use of the weapon and implies that Oppenheimer was being hypocritical. Hydrogen bomb Despite an offer from Norris Bradbury, who had replaced Oppenheimer as the director of Los Alamos in November 1945, to become the head of the Theoretical (T) Division, Teller left Los Alamos on February 1, 1946, to return to the University of Chicago as a professor and close associate of Fermi and Goeppert-Mayer. Mayer's work on the internal structure of the elements would earn her the Nobel Prize in Physics in 1963. On April 18–20, 1946, Teller participated in a conference at Los Alamos to review the wartime work on the Super. The properties of thermonuclear fuels such as deuterium and the possible design of a hydrogen bomb were discussed. It was concluded that Teller's assessment of a hydrogen bomb had been too favourable, and that both the quantity of deuterium needed, as well as the radiation losses during deuterium burning, would shed doubt on its workability. Addition of expensive tritium to the thermonuclear mixture would likely lower its ignition temperature, but even so, nobody knew at that time how much tritium would be needed, and whether even tritium addition would encourage heat propagation. At the end of the conference, in spite of opposition by some members such as Robert Serber, Teller submitted an optimistic report in which he said that a hydrogen bomb was feasible, and that further work should be encouraged on its development. Fuchs also participated in this conference, and transmitted this information to Moscow. With John von Neumann, he contributed an idea of using implosion to ignite the Super. The model of Teller's "classical Super" was so uncertain that Oppenheimer would later say that he wished the Russians were building their own hydrogen bomb based on that design, so that it would almost certainly delay their progress on it. By 1949, Soviet-backed governments had already begun seizing control throughout Eastern Europe, forming such puppet states as the Hungarian People's Republic in