Duba wurin da ke ƙasa sannan ka amsa tambayar daga baya a cikin harshe ɗaya kamar yadda wurin yake:  Passage: Ya koma Cibiyar Nazarin Kimiyya (daga baya Cibiyar Niels Bohr) a Copenhagen a kan Sheldon Traveling Fellowship daga Harvard, kuma ya kasance a Denmark. A cikin 1953 an nada shi memba na ma'aikaci a CERN's Theoretical Study Group, wanda ke da hedikwata a Copenhagen, matsayin da ya riƙe har ya zama farfesa a sabon Cibiyar Nazarin Ilimin Kimiyya ta Nordic (Nordita) a 1957. Ya kasance farfesa mai ziyara a Jami'ar California, Berkeley a cikin Spring 1959. A shekara ta 1971 ya zama dan kasar Danish.  Tambaya: Yaushe ya zama dan kasar Denmark?
Shekara ta 1971