Edward Teller

Known as the father of the hydrogen bomb, Teller pushed relentlessly for fusion weapons through the Manhattan Project and after, while also making lasting contributions to physics and chemistry — the Jahn–Teller effect, Gamow–Teller beta-decay transitions, and a 1953 paper that helped found the Monte Carlo method in statistical mechanics. Born in Budapest, he fled fascism in the 1930s as one of a wave of Hungarian émigré physicists nicknamed "the Martians." His 1954 testimony against Robert Oppenheimer's security clearance, in which he alone among physicists said he did not trust Oppenheimer's judgment, cost him standing among scientists for the rest of his life.