The most significant work was done by Eugene Wigner (who came from Hungary), George Gamow (Russia), FelixBloch (Switzerland), Hans Bethe (Germany), Edward Teller (Hungary), and Victor Weisskopf (Austria).
In addition, four of the nuclear scientists who came to the United States from Europe in the 1930s later received a Nobel Prize for physics: FelixBloch, born in Switzerland, won it in 1952, Emilio Segre (Italy) won in 1959, and Maria Mayer (Poland) and Eugene Wigner (Hungary) won the award in 1963.