Victor Frederick Weisskopf, 1908-2002 - Theoretical Physics at LBNL

10 BIOGRAPHICAL MEMOIRSby the professor’s assignations. Schrödinger showed anotherside by arranging a one-year Rockefeller Fellowship for Vikito begin in the fall of 1932. For the long summer periodViki and his current girl friend went to Kharkov in theSoviet Union, where Lev Landau was. This was the first ofseveral trips to the Soviet Union, trips that both opened hiseyes to the evils of the regime and made friendships withSoviet scientists that were useful in different ways later inhis life.During his postdoc period Viki developed close friendshipswith many young colleagues who were rapidly becomingprominent physicists, especially Patrick Blackett, FelixBloch, Hendrik Casimir, Rudolf Peierls, and George Placzek,as well as Max Delbrück, who left quantum field theory tobecome a great pioneer in molecular biology. And in 1932on his second day in Copenhagen Viki met Ellen Tvede,who was soon to be his wife and constant companion untilher death in 1989. By this time Viki seemed to have lost theshyness remarked on by Born. In his reminiscences 3 HendrikCasimir notes that in Copenhagen Viki participated in theentertainments at Bohr Institute conferences by “provid[ing]both poetry and song” and by taking the role of the DalaiLama.Three central problems of quantum electrodynamics(QED) were the focus of Viki’s research during his postdoctoralperiod: the role of antiparticles, the self-energy ofthe electron, and the properties of the vacuum in QED.The puzzling negative energy solutions of Dirac’s amazinglysuccessful relativistic wave equation were in 1932 proposedby Dirac to correspond to antiparticles of the same mass asthe electron but of opposite charge, an interpretation thatwas highly controversial. Nevertheless, such particles werediscovered in cosmic-ray experiments later that year, butthat these objects were indeed Dirac’s antiparticles was not