Editing J. Robert Oppenheimer (section)

=== Institute for Advanced Study ===
[[File:Einstein oppenheimer.jpg|thumb|left|Oppenheimer and [[Albert Einstein]] had been colleagues and shared a cordial [[Einstein–Oppenheimer relationship|relationship]] with each other. {{circa|1950}}|alt=Einstein writing at a desk. Oppenheimer sits beside him, looking on.]]

In November 1945, Oppenheimer left Los Alamos to return to Caltech,<ref>{{harvnb|Bird|Sherwin|2005|pp=333–335}}</ref> but soon found that his heart was no longer in teaching.<ref>{{harvnb|Bird|Sherwin|2005|p=351}}</ref> In 1947, he accepted an offer from [[Lewis Strauss]] to take up the directorship of the [[Institute for Advanced Study]] in [[Princeton, New Jersey]]. This meant moving back east and leaving [[Ruth Sherman Tolman|Ruth Tolman]], the wife of his friend Richard Tolman, with whom he had begun an affair after leaving Los Alamos.<ref>{{harvnb|Bird|Sherwin|2005|pp=360–365}}</ref> The job came with a salary of $20,000 per annum, plus rent-free accommodation in the director's house, a 17th-century manor with a cook and [[groundskeeper]], surrounded by {{convert|265|acre}} of woodlands.<ref>{{harvnb|Bird|Sherwin|2005|p=369}}</ref> He collected European furniture, and French [[Post-Impressionist]] and [[Fauvist]] artworks. His art collection included works by [[Cézanne]], [[Derain]], [[Despiau]], [[Maurice de Vlaminck|de Vlaminck]], Picasso, [[Rembrandt]], [[Renoir]], Van Gogh and Vuillard.<ref>{{cite web |url=http://research.frick.org/directoryweb/browserecord.php?-action=browse&-recid=12000 |title=Oppenheimer, J. Robert, 1904–1967 |publisher=Archives Directory for the History of Collecting |access-date=August 24, 2019 |archive-date=April 5, 2016 |archive-url=https://web.archive.org/web/20160405200608/http://research.frick.org/directoryweb/browserecord.php?-action=browse&-recid=12000 |url-status=live }}</ref>

Oppenheimer brought together intellectuals at the height of their powers and from a variety of disciplines to answer the most pertinent questions of the age. He directed and encouraged the research of many well-known scientists, including [[Freeman Dyson]], and the duo of [[Chen Ning Yang]] and [[Tsung-Dao Lee]], who won a Nobel Prize for their discovery of [[Parity (physics)|parity]] non-conservation. He also instituted temporary memberships for scholars from the humanities, such as [[T. S. Eliot]] and [[George F. Kennan]]. Some of these activities were resented by a few members of the mathematics faculty, who wanted the institute to stay a bastion of pure scientific research. Abraham Pais said that Oppenheimer himself thought that one of his failures at the institute was being unable to bring together scholars from the natural sciences and the humanities.<ref>{{harvnb|Bird|Sherwin|2005|pp=371–377}}</ref>

During a series of conferences in New York—the [[Shelter Island Conference]] in 1947, the [[Pocono Conference]] in 1948, and the [[Oldstone Conference]] in 1949—physicists transitioned from war work back to theoretical issues. Under Oppenheimer's direction, physicists tackled the greatest outstanding problem of the pre-war years: infinite, divergent, and seemingly nonsensical expressions in the quantum electrodynamics of [[elementary particle]]s. [[Julian Schwinger]], [[Richard Feynman]] and [[Shin'ichiro Tomonaga]] tackled the problem of [[Regularization (physics)|regularization]], and developed techniques that became known as [[renormalization]]. Freeman Dyson was able to prove that their procedures gave similar results. The problem of [[meson]] absorption and [[Hideki Yukawa]]'s theory of mesons as the carrier particles of the [[strong nuclear force]] were also tackled. Probing questions from Oppenheimer prompted [[Robert Marshak]]'s innovative two-meson [[hypothesis]]: that there are actually two types of mesons, [[pion]]s and [[muon]]s. This led to [[Cecil Frank Powell]]'s breakthrough and subsequent Nobel Prize for the discovery of the pion.<ref>{{harvnb|Cassidy|2005|pp=269–272}}</ref>{{refn|group=note| Due to the subsequent development of the [[Standard Model]], the muon is now considered to be a [[lepton]] and not a meson.<ref>{{harvnb|Spangenburg|Moser|2004|pp=41–44}}</ref>}}

Oppenheimer served as director of the institute until 1966, when he gave up the position due to his failing health.<ref name="nyt-obit"/> {{as of|2023}}, he is the longest-serving director of the institute.<ref>{{Cite web |title=J. Robert Oppenheimer – Past Director |url=https://www.ias.edu/scholars/oppenheimer |access-date=August 10, 2023 |website=[[Institute for Advanced Study]] |date=December 9, 2019 |archive-date=May 3, 2017 |archive-url=https://web.archive.org/web/20170503213727/https://www.ias.edu/scholars/oppenheimer |url-status=live }}</ref>