Los Alamos National Laboratory · Attribution

A theoretical physicist who worked alongside Heisenberg, Pauli and Bohr on the foundations of quantum electrodynamics, then led the Theoretical Division's deputy leadership at Los Alamos during the Manhattan Project. After the war he helped develop the Conwell-Weisskopf theory of electron movement in semiconductors, work that underpins modern computing, and served as Director-General of CERN from 1961 to 1965. Later in life he co-founded the Union of Concerned Scientists and, at the request of Pope John Paul II, led a delegation of scientists to Washington to argue for nuclear disarmament.