Editing J. Robert Oppenheimer (section)

=== Studies in Europe ===
[[File:Leiden Kamerlingh-Onnes Lab.jpg|thumb|left|upright=1.5|[[Heike Kamerlingh Onnes]]' Laboratory in [[Leiden]], Netherlands, July 1927. Oppenheimer is in the middle row, second from the left.|alt=Fifteen men in suits, and one woman, pose for a group photograph]]
After being accepted at [[Christ's College, Cambridge]], in 1924, Oppenheimer wrote to [[Ernest Rutherford]] requesting permission to work at the [[Cavendish Laboratory]], though Bridgman's letter of recommendation said that Oppenheimer's clumsiness in the laboratory suggested that theoretical, rather than experimental, physics would be his forte. Rutherford was unimpressed, but Oppenheimer went to Cambridge nonetheless;<ref>{{harvnb|Cassidy|2005|pp=90–92}}</ref> [[J. J. Thomson]] ultimately accepted him on the condition that he complete a basic laboratory course.<ref>{{harvnb|Cassidy|2005|p=94}}</ref>

Oppenheimer was very unhappy at Cambridge and wrote to a friend: "I am having a pretty bad time. The lab work is a terrible bore, and I am so bad at it that it is impossible to feel that I am learning anything."{{sfn|Monk|2012|p=92}} He developed an antagonistic relationship with his tutor, [[Patrick Blackett]], a future Nobel laureate. According to Oppenheimer's friend [[Francis Fergusson]], Oppenheimer once confessed to leaving a poisoned apple on Blackett's desk, and Oppenheimer's parents convinced the university authorities not to expel him. There are no records of either a poisoning incident or probation, but Oppenheimer had regular sessions with a psychiatrist in [[Harley Street]], London.{{sfn|Bird|Sherwin|2005|p=46}}{{sfn|Monk|2012|p=97}}<ref>{{cite magazine|author=McCluskey, Megan|title=J. Robert Oppenheimer's Grandson on What the Movie Gets Right and the One Scene He Would Have Changed|url=https://time.com/6297743/oppenheimer-grandson-movie-interview/|magazine=[[Time (magazine)|Time]]|date=July 25, 2023|access-date=July 26, 2023|archive-date=July 27, 2023|archive-url=https://archive.today/20230727190222/https://time.com/6297743/oppenheimer-grandson-movie-interview/|url-status=live}}</ref><ref>{{cite web |title=Oppenheimer and the poisoned apple |date=August 15, 2023 |publisher=Cambridge University Library Special Collections |url=https://specialcollections-blog.lib.cam.ac.uk/?p=26027 |access-date=December 9, 2023 |archive-date=December 9, 2023 |archive-url=https://web.archive.org/web/20231209170716/https://specialcollections-blog.lib.cam.ac.uk/?p=26027 |url-status=live }}</ref>
Oppenheimer was a tall, thin [[Chain smoking|chain smoker]],<ref>{{harvnb|Bird|Sherwin|2005|pp=39–40, 96, 258}}</ref> who often neglected to eat during periods of intense concentration. Many friends said he could be self-destructive. Fergusson once tried to distract Oppenheimer from apparent depression by telling him about his girlfriend, Frances Keeley, and how he had proposed to her. Oppenheimer jumped on Fergusson and tried to strangle him. Oppenheimer was plagued by periods of depression throughout his life,<ref>{{harvnb|Smith|Weiner|1980|p=91}}</ref><ref>{{harvnb|Bird|Sherwin|2005|pp=35–36, 43–47, 51–52, 320, 353}}</ref> and once told his brother, "I need physics more than friends."<ref>{{harvnb|Smith|Weiner|1980|p=135}}</ref>

In 1926, Oppenheimer left Cambridge for the [[University of Göttingen]] to study under [[Max Born]]; Göttingen was one of the world's leading centers for theoretical physics. Oppenheimer made friends who went on to great success, including [[Werner Heisenberg]], [[Pascual Jordan]], [[Wolfgang Pauli]], [[Paul Dirac]], [[Enrico Fermi]] and [[Edward Teller]]. He was enthusiastic in discussions to the point of sometimes taking them over.<ref>{{harvnb|Cassidy|2005|p=108}}</ref> [[Maria Goeppert]] presented Born with a petition signed by herself and others threatening a boycott of the class unless he made Oppenheimer quiet down. Born left it out on his desk where Oppenheimer could read it, and it was effective without a word being said.<ref>{{harvnb|Bird|Sherwin|2005|p=60}}</ref>

Oppenheimer obtained his [[Doctor of Philosophy]] degree in March 1927 at age 23, supervised by Born.<ref name=phd>{{cite thesis|degree=PhD|first=Julius Robert|last=Oppenheimer|year=1927|title=Zur Quantentheorie kontinuierlicher Spektren|oclc=71902137}}</ref><ref>{{harvnb|Cassidy|2005|p=109}}</ref> After the oral exam, [[James Franck]], the professor administering it, reportedly said, "I'm glad that's over. He was on the point of questioning ''me''."<ref name="Eternal Apprentice">{{cite magazine |date=November 8, 1948 |title=The Eternal Apprentice |magazine=[[Time (magazine)|Time]] |url=http://content.time.com/time/magazine/article/0,9171,853367,00.html |url-access=subscription |access-date=May 23, 2008 |archive-date=October 7, 2013 |archive-url=https://web.archive.org/web/20131007024559/http://content.time.com/time/magazine/article/0,9171,853367,00.html |url-status=live }}</ref> Oppenheimer published more than a dozen papers while in Europe, including many important contributions to the new field of quantum mechanics. He and Born published a famous paper on the [[Born–Oppenheimer approximation]], which separates nuclear motion from electronic motion in the mathematical treatment of molecules, allowing nuclear motion to be neglected to simplify calculations. It remains his most cited work.<ref>{{harvnb|Cassidy|2005|p=112}}</ref>