Dyson kwagara United States na 1947 dị ka onye Commonwealth Fellow iji nweta doctorate physics na Hans Bethe na Cornell University (1947<unk>48). N'ebe ahụ, ọ maara Richard Feynman. Ọkà mmụta sayensị Bekee na-eto eto ghọtara ịdị mma nke onye America ahụ na-egbuke egbuke, ma tinye onwe ya ngwa ngwa o kwere mee. Mgbe ahụ ọ kwagara na Institute for Advanced Study (1948<unk>49), tupu ọ laghachi England (1949<unk>51), ebe ọ bụ onye nyocha na Mahadum Birmingham. Na 1949 Dyson gosipụtara nha anya nke usoro abụọ nke electrodynamics quantum (QED): Richard Feynman's diagram na usoro onye ọrụ nke Julian Schwinger na Shin Shin Ward. Ọ bụ ezie na ọ bụ onye mbụ mgbe onye na-emepụta ha ka ọ na-enweta doctorate na physics na Cornell na-arụ ọrụ na Cornell na-arụ ọrụ na J. Feynman na 1948 na-arụ ọrụ na Princeton Advanced Study, ọ ka na-arụ ọrụ na ya dị ka onye na-arụ ọrụ na ngalaba nke physics na-arụ ọrụ na ya. Ọ bụ onye edemede na-arụ ọrụ n'ụlọ akwụkwọ na 1951
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