Robert Oppenheimer

J. Robert Oppenheimer (April 22, 1904 – February 18, 1967) was an American physicist of German-Jewish origin, and the scientific director of the Manhattan Project, the World War II effort to develop the first nuclear weapons, at the secret Los Alamos laboratory in New Mexico. Known colloquially as "the father of the atomic bomb", Oppenheimer lamented the weapon's killing power after it was used to destroy the Japanese cities of Hiroshima and Nagasaki. After the war, he was a chief advisor to the newly created Atomic Energy Commission and used that position to lobby for international control of atomic energy and to avert the nuclear arms race with the Soviet Union. After invoking the ire of many politicians and scientists with his outspoken political opinions during the Red Scare, he had his security clearance revoked in a much-publicized and politicized hearing in 1954. Though stripped of his direct political influence, Oppenheimer continued to lecture, write, and work in physics. A decade later, President Lyndon B. Johnson awarded him the Enrico Fermi Award as a gesture of rehabilitation.

Early life and education

Robert Oppenheimer was born in New York City on April 22, 1904 to Julius S. Oppenheimer (a wealthy textile importer who had emigrated to the United States from Germany in 1888) and Ella Friedman, an artist. He studied at the Ethical Culture Society School (whose physics laboratory has since been named for him) where, in addition to mathematics and science, he was exposed to a variety of subjects ranging from Greek to French literature, and met with success at the school's particular form of ethical training, based on the secular Judaism of its founder, Felix Adler (the Oppenheimers were of Jewish descent but they did not observe the religious traditions). Throughout his life, he remained a versatile scholar, proficient in science as well as the humanities. He entered Harvard University one year late due to an attack of colitis. During the interim, he went with a former English teacher to recuperate in New Mexico, where he fell in love with horseback riding and the mountains and plateaux of the Southwest. He returned reinvigorated and made up for the delay by graduating Summa Cum Laude in just three years with a major in chemistry.

Related Topics:
New York City - United States - Germany - 1888 - Ethical Culture Society School - Judaism - Felix Adler - Jewish - Harvard University - Colitis - English - New Mexico - Horseback riding - Southwest - Summa Cum Laude - Chemistry

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Europe

While at Harvard, Oppenheimer was introduced to experimental physics during a course on thermodynamics taught by Percy Bridgman, and was encouraged to go to Europe for future study, as a world-class education in the subject could not then be obtained in the United States. He was accepted for postgraduate work at Ernest Rutherford's famed Cavendish Laboratory in Cambridge, working under the eminent but aging J.J. Thomson. Oppenheimer's clumsiness in the laboratory made it apparent that his forte was theoretical, not experimental, physics, so he left in 1926 for the University of Göttingen to study under Max Born. Göttingen was one of the top centers for theoretical physics in Europe, and Oppenheimer made a number of friends who would go on to great success, such as Paul Dirac, before he obtained his Ph.D. at the age of 22. At Göttingen, Oppenheimer was known for being a quick study. However, he was also known for being too enthusiastic in discussions, sometimes to the point of taking over seminar sessions, a fact that used to irritate a few of Born's pupils.

Related Topics:
Thermodynamics - Percy Bridgman - Europe - Ernest Rutherford - Cavendish Laboratory - Cambridge - J.J. Thomson - 1926 - University of Göttingen - Max Born - Paul Dirac - Ph.D.

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At Göttingen, Oppenheimer published many important contributions to the then newly developed quantum theory, most notably a famous paper on the so-called Born-Oppenheimer approximation, which separates nuclear motion from electronic motion in the mathematical treatment of molecules. In September 1927, he returned to Harvard as a young maven of mathematical physics and a National Research Council Fellow, and in early 1928 he studied at the California Institute of Technology. Here he received numerous invitations for teaching positions, and accepted an assistant professorship in physics at the University of California, Berkeley. In his words, "it was a desert", yet paradoxically a fertile place of opportunity. He maintained a joint appointment with Caltech, where he spent every spring term in order to avoid isolation from mainstream research. At Caltech, Oppenheimer struck a close friendship with Linus Pauling and they planned to mount a joint attack on the nature of the chemical bond, a field in which Pauling was a pioneer—apparently Oppenheimer would supply the mathematics and Pauling would interpret the results. However, this relationship was nipped in the bud when Pauling began to suspect that the theorist was becoming too close to his wife, Ava Helen; once when Pauling was at work, Oppenheimer had come to their place and blurted out an invitation to Ava Helen to join him on a tryst in Mexico. She flatly refused and reported this incident to Pauling. This, and her apparent nonchalance about the incident, disquieted him, and he immediately cut off his relationship with the Berkeley professor, leading to a coolness between them that would last their lives, although Oppenheimer did invite Pauling to be the head of the Chemistry Division of the atomic bomb project (Pauling refused, saying that he was a pacifist).

Related Topics:
Quantum theory - Born-Oppenheimer approximation - 1927 - 1928 - California Institute of Technology - University of California, Berkeley - Linus Pauling - Mexico - Pacifist

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In the fall of 1928, Oppenheimer visited Paul Ehrenfest's institute at the University of Leiden, the Netherlands, where he impressed those there by giving lectures in Dutch despite his little experience with the language. There he was given the nickname of "Opje", which was later Anglicised by his students as "Oppie". From Leiden he continued on to Zurich, Switzerland, to work with Wolfgang Pauli on problems relating to quantum theory and the continuous spectrum, before heading back to the United States. Oppenheimer highly respected and liked Pauli, and some of his own style and his critical approach to problems was said to be inspired by Pauli. His time with both Ehrenfest and Pauli gave Oppenheimer a chance to polish his mathematical skills.

Related Topics:
Paul Ehrenfest - University of Leiden - Netherlands - Dutch - Zurich - Switzerland - Wolfgang Pauli

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California

Before his Berkeley professorship began, Oppenheimer was diagnosed with a mild case of tuberculosis, and with his brother Frank, spent some weeks at a ranch in New Mexico, which he leased and eventually purchased. (When he heard the ranch was available for lease, he exclaimed, "Hot dog!"—and since it was in New Mexico, the Oppenheimer brothers named it "Perro Caliente", the literal Spanish translation of this exclamation.http://ohst.berkeley.edu/oppenheimer/exhibit/text/ch1page1.html) Later, Oppenheimer used to say that 'physics and desert country' were his two great loves, loves that would be improbably combined when he directed the atomic bomb project at Los Alamos in New Mexico.

Related Topics:
Tuberculosis - Frank

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He recovered from his tuberculosis and returned to Berkeley, where he prospered as an advisor and collaborator to a generation of physicists who admired him for his intellectual virtuosity and broad interests. Nobel Prize winner Hans Bethe later said about him:

Related Topics:
Nobel Prize winner - Hans Bethe

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:Probably the most important ingredient Oppenheimer brought to his teaching was his exquisite taste. He always knew what were the important problems, as shown by his choice of subjects. He truly lived with those problems, struggling for a solution, and he communicated his concern to the group.

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He also worked closely with (and became good friends with) experimental physicist Ernest O. Lawrence and his cyclotron pioneers, helping the experimentalists understand the new data their machines were producing at the Lawrence's Radiation Laboratory.

Related Topics:
Ernest O. Lawrence - Cyclotron - Radiation Laboratory

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Oppenheimer became credited with being a founding father of the American school of theoretical physics, and developed a reputation for his eclecticism, his interest in languages and Eastern philosophy, and the eloquence and clarity with which he thought. But he was also troubled throughout his life, and professed to experiencing periods of depression. "I need physics more than friends," he once informed his brother. A tall, thin chain smoker who often neglected to eat during periods of intellectual discomfort and concentration, Oppenheimer was marked by many of his friends as having a self-destructive tendency, and during numerous periods of his life worried his colleagues and associates with his melancholy and insecurity. When he was studying in Cambridge and had taken a vacation to meet up with his friend Francis Ferguson in Paris, a disturbing event had taken place. During a conversation in which Oppenheimer was narrating his frustration with experimental physics to Ferguson, he had suddenly leapt up and tried to strangle him. Although Ferguson easily fended off the attack, the episode had convinced Ferguson of his friend's deep psychological troubles. Oppenheimer developed numerous affectations, seemingly in an attempt to convince those around him—or possibly himself—of his self-worth. He was said to be mesmerizing, hypnotic in private interaction but often frigid in more public settings. His associates fell into two camps: one which saw him as an aloof and impressive genius and an aesthete; another which saw him as a pretentious and insecure poseur. His students almost always fell into the former category, adopting "Oppie's" affectations, from his way of walking to talking and beyond.

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Oppenheimer did important research in astrophysics, nuclear physics, spectroscopy, and quantum field theory. His best-known contribution, made as a graduate student, is the Born-Oppenheimer approximation mentioned above. He also made important contributions to the theory of cosmic ray showers, and did work which led eventually toward descriptions of quantum tunneling. In the late 1930s, he was the first to write papers suggesting the existence of what we today call black holes. After the Born-Oppenheimer approximation paper, these papers remain his most cited ones, and they were key in the rejuvenation of astrophysical research in the United States in the 1950s, mainly by John Wheeler. As early as 1930, he also wrote a paper essentially predicting the existence of the positron (which had been postulated by Paul Dirac), a formulation that he however did not carry to its natural outcome, because of his skepticism about the validity of the Dirac equation. Even beyond the immense abstruseness of the topics he was expert in, Oppenheimer's papers were considered difficult to understand. Oppenheimer was very fond of using elegant, if extremely complex, mathematical techniques to demonstrate physical principles, though he was sometimes criticized for making mathematical mistakes, presumably out of haste.

Related Topics:
Astrophysics - Nuclear physics - Spectroscopy - Quantum field theory - Born-Oppenheimer approximation - Cosmic ray - Quantum tunneling - 1930s - Black holes - John Wheeler - Positron - Paul Dirac - Dirac equation

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Many people thought that Oppenheimer's discoveries and research were not commensurate with his inherent abilities and talents. They still considered him an outstanding physicist, but they did not place him at the very top rank of theorists who fundamentally challenged the frontiers of knowledge. One reason for this could have been his diverse interests, which kept him from completely focusing on any individual topic for long enough to bring it to full fruition. His close confidant and colleague Isidor Rabi later gave his own interpretation:

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:Oppenheimer was overeducated in those fields which lie outside the scientific tradition, such as his interest in religion, in the Hindu religion in particular, which resulted in a feeling of mystery of the universe that surrounded him like a fog. He saw physics clearly, looking toward what had already been done, but at the border he tended to feel there was much more of the mysterious and novel than there actually was...he turned away from the hard, crude methods of theoretical physics into a mystical realm of broad intuition.

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In spite of this, some people (such as the physicist Luis Alvarez) have suggested that if he had lived long enough to see his predictions substantiated by experiment, Oppenheimer might have won a Nobel Prize for his work on gravitational collapse, concerning neutron stars and black holes.

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Radical politics

During the 1920s, Oppenheimer kept himself aloof of worldly matters, and claimed to have not learned of the stock market crash of 1929 until some time after the fact (Oppenheimer himself had little worry regarding financial matters, as his family inheritance provided him with ample funding). It was not until he became involved with Jean Tatlock, the daughter of a Berkeley literature professor, in 1936, that he showed any interest in politics. Like many young intellectuals in the 1930s he became a supporter of Communist ideas, and having much more money than most professors (he inherited over $300,000, a massive sum at the time, after his father's death in 1937) was able to bankroll many left-wing efforts. The majority of his radical work consisted of hosting fund-raisers for the Republican cause in the Spanish Civil War and other anti-Fascist activity, and he never openly joined the Communist Party (his brother Frank, however, did, against Robert's advice), though the historian Gregg Herken has recently claimed to have evidence that Oppenheimer did interact with the Communist Party during the 1930s and early 1940s.http://www.nybooks.com/articles/17008 In November 1940, he married Katherine Puening Harrison, a radical Berkeley student, and by May 1941 they had their first child, Peter.

Related Topics:
1920s - Stock market crash - 1929 - Jean Tatlock - 1936 - 1930s - Communist - 1937 - Left-wing - Republican - Spanish Civil War - Fascist - Communist Party - 1940 - 1941

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