Dyson gbe lọ si United States ni 1947 bi a Commonwealth Fellow lati jo'gun a fisiksi doctorate pẹlu Hans Bethe ni Cornell University (1947<unk>48). Nibẹ ni o ṣe awọn acquaintance ti Richard Feynman. The budding English fisiksi mọ awọn brilliance ti awọn flamboyant American, ati ki o so ara rẹ bi ni kiakia bi o ti ṣee. O si lọ si Institute for Advanced Study (1948<unk>49), ṣaaju ki o to pada si England (1949<unk>51), ibi ti o ti a iwadi ẹlẹgbẹ ni University of Birmingham.In 1949 Dyson fihan awọn equivalence ti meji formulations ti quantum electrodynamics (QED): Richard Feynman ká aworan ati awọn ọna ti ni idagbasoke nipa Julian Schwinger ati Shinir Ward.
Ìṣẹ̀lẹ̀ Orion