The science and personality of J. Robert Oppenheimer
‘Father of the atomic bomb’ is the focus of conference, exhibits this weekend — the centennial of his birth
| 21 April 2004
J. Robert Oppenheimer was one of the 20th century’s tragic figures, a brilliant Berkeley physicist who corralled the brains and talent to create the atomic bomb, only to be pilloried later by anti-communist witch hunters and stripped of his government security clearance.
“Historians still think that Oppenheimer was a controversial figure,” said associate professor of history Cathryn Carson, director of the Office for History of Science and Technology. She is one of the organizers (with Berkeley historian David Hollinger) of this weekend’s conference, “Oppenheimer as Scientific Intellectual.” Along with a range of talks and exhibits, it is part of the campus’s centennial celebration of Oppenheimer’s birth. (See "Oppenheimer opportunities" for details of centennial events.)
“It’s not hard to find partisan history and perspective on Oppenheimer’s life, but there is a real gap in the availability of reliable and reputable information,” Carson continued. “We can do a real service by giving information and context.”
Oppenheimer’s significance in the history of American physics rests on more than his role in the Manhattan Project. When he came to Berkeley in 1929 at the age of 25, theoretical physics in the United States was essentially non-existent.
“Theorists were largely calculators, handmaidens to the experimentalists who dominated physics departments in the U.S. until the 1940s,” said Carson, a specialist in 20th-century German physics, in particular the history of quantum mechanics.
“Oppenheimer turned Berkeley into the nation’s first center of theoretical physics, a place where good American students could get a grounding in theory that rivaled any in Europe,” Carson noted.. Oppenheimer had spent two years in Göttingen, Germany, learning the new theories of quantum mechanics and relativity from Max Born and a coterie of the world’s top physicists. He returned to the U.S. in 1927 with a freshly minted Ph.D. and took a fellowship at the California Institute of Technology, with which he maintained a connection after joining Berkeley’s physics department in 1929.
“He really had a big impact on Berkeley and Caltech from the standpoint of theoretical physics,” said theoretician Marvin Cohen, University Professor of Physics. “He was very smart, very fast, very competitive, and he brought this teaching of quantum mechanics, which has been so central to the development of physics since the 1920s. Students clustered around him to learn the details of these new theories.”
When he first arrived, Oppenheimer (his students called him “Oppie”) considered UC Berkeley a “desert,” but he quickly built a strong theoretical physics center here, working closely with experimentalist par excellence Ernest O. Lawrence, who later won a Nobel Prize for his invention of the cyclotron. The recruitment of the two rising stars was due largely to Raymond Birge, the only UC physicist up to that time to enjoy an international reputation for his work, which for a time centered on a precise spectroscopic measurement of Planck’s constant, which plays a central role in the theory of quantum mechanics.
Oppenheimer’s publications are sparse, and to laypeople he is known primarily for calculations of condensed states of matter so dense they collapse onto themselves, creating what are now known as neutron stars and black holes. Yet he also published with Born a way to simplify quantum mechanical calculations involving molecules, a method known and used today as the Born-Oppenheimer approximation, and he made essential contributions to the quantum theory of fields.
Because he worked closely with students, however, much of his work is indistinguishable from their own, Carson said. “He didn’t publish a lot, but he often helped on projects without insisting on credit in the publication.”
Oppenheimer’s bohemian ways and flirtation with communist groups in the Bay Area set the stage for his later fall. Despite FBI concerns about his loyalty, the U.S. Army chose him to head the Manhattan Engineer District project in 1942, and he set out immediately to recruit the best physicists, chemists, and mathematicians in the nation. He even proposed a site for the secret lab that was to build an atomic bomb — the top of a mesa then occupied by a private boys school called Los Alamos Ranch School, not far from Santa Fe.
The group’s success in achieving a nuclear explosion on July 16, 1945, was a tribute to Oppenheimer’s organizational abilities, inspiring leadership, and choice of scientists. By August the United States had dropped bombs on Hiroshima and Nagasaki, Japan had surrendered, and the war was over. Los Alamos scientists began trickling home, and Oppenheimer resigned his post in October 1945.
From Berkeley to New Jersey — but why?
One of the big questions, Carson said, is why Oppenheimer decided not to stay at UC Berkeley. Despite offers of a doubled salary and the importuning of Lawrence and Birge, in 1947 he took the role of director of the Institute for Advanced Study in Princeton, N.J. Though Albert Einstein was the institute’s most famous resident, he was largely inactive, and at the time the place was a bit of a backwater, said Vettel.
Oppenheimer evidently felt unwanted at UC, remarking that UC President Robert Gordon Sproul didn’t want him to return because of his “difficult temperament and poor judgement,” according to a Sproul memo. (Sproul denied this.) Robert Underhill, the UC manager who oversaw the Los Alamos lab during the war (and one of the few UC administrators privy to the bomb work), also made life difficult for Oppenheimer. And, said Vettel, Oppenheimer’s relationship with Lawrence had become strained, as had his relations with others in the Berkeley physics department.
According to Carson, Birge said that his inability to keep Oppenheimer was “the greatest failure of my life.”
It was only later, in 1953, that Oppenheimer was accused of consorting with Communists and, as an indication of his disloyalty, opposing the building of the hydrogen bomb. After hearings that dredged up episodes from his Berkeley years, his security clearance was canceled, and his contract as an advisor to the Atomic Energy Commission was severed. Oppenheimer, who died in 1967 of throat cancer, is still viewed internationally as the tragic victim of a witch hunt.
Despite his apparently ambivalent feelings toward Berkeley, Oppenheimer left a significant legacy. “By the end of World War II, Berkeley was a center for theoretical and experimental physics,” said Vettel. Adds Marvin Cohen: “The fact that Oppenheimer was here attracted other people who wanted to be around him, though they were a bit afraid of him. He was a star.”