Ka haere ia ki te Institute for Theoretical Physics (i muri mai ko te Niels Bohr Institute) i Copenhagen i runga i te Sheldon Traveling Fellowship mai i Harvard, a ka noho ki Denmark. I te 1953 i tohua ia hei kaimahi i te Rōpū Akoranga Theoretical o CERN, i noho ki Copenhagen, he tūranga i mau ia tae noa ki te wa i riro ai ia hei kaiwhakaako i te Nordic Institute for Theoretical Physics (Nordita) i te tau 1957. He kaiwhakaako manuhiri ia i te Whare Wananga o California, Berkeley i te puna o te tau 1959. I te tau 1971 ka riro ia hei tangata whenua o Denmark. Pātai: I te wa i riro ai ia hei tangata whenua o Denmark?
Ko te tau 1971