Richard Feynman

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Richard Phillips Feynman (May 11, 1918 – February 15, 1988; surname pronounced FINE-man; /ˈfaɪnmən/) was an American physicist known for his scientific acumen, humor, and charismatic charm. His accomplishments in physics included expanding the theory of quantum electrodynamics, the physics of the superfluidity of supercooled liquid helium, and particle theory. His work on quantum electrodynamics made him a joint recipient of the Nobel Prize in Physics in 1965, together with Julian Schwinger and Sin-Itiro Tomonaga; he developed a way to understand the behavior of subatomic particles using pictorial tools that later became known as Feynman diagrams.

Along with several of the other leading physicists of his era, he assisted in the development of the atomic bomb in the Manhattan Project and was a member of the panel that investigated the Space Shuttle Challenger disaster. In addition to his work in theoretical physics, Feynman is credited with the concept and early exploration of quantum computing, and publicly envisioning nanotechnology, creation of devices at the molecular scale. He held the Richard Chace Tolman professorship in theoretical physics at Caltech.

Feynman was a keen and influential popularizer of physics in both his books and lectures, notably a seminal 1959 talk on top-down nanotechnology called There's Plenty of Room at the Bottom and The Feynman Lectures on Physics, a three-volume set which has become a classic text. Known for his insatiable curiosity, wit, brilliant mind and playful temperament,[1] he is equally famous for his many adventures, detailed in his books Surely You're Joking, Mr. Feynman!, What Do You Care What Other People Think? and Tuva or Bust!. As well as being an inspirational lecturer, bongo player, notorious practical joker, and decipherer of Maya hieroglyphs, Richard Feynman was regarded as an eccentric and a free spirit. He liked to pursue multiple seemingly independent paths, such as biology, art, percussion, and lock picking. Freeman Dyson once wrote that Feynman was "half-genius, half-buffoon", but later revised this to "all-genius, all-buffoon".

## The Manhattan Project[edit]

After the attack on Pearl Harbor brought the United States into the war, Feynman was recruited by Robert R. Wilson, who was working on means to produce enriched uranium for use in an atomic bomb, as part of what would become the Manhattan Project. Wilson's team at Princeton was working on a device called an isotron, intended to electromagnetically separate uranium-235 from uranium-238. This was done in a quite different manner from that used by the calutron that was under development by a team under Wilson's former mentor, Ernest O. Lawrence, at the Radiation Laboratory of the University of California. On paper, the isotron was many times more efficient than the calutron, but Feynman and Paul Olum struggled to determine whether it was practical. Ultimately, on Lawrence's recommendation, the isotron project was abandoned

At this juncture, in early 1943, Robert Oppenheimer was establishing the Los Alamos Laboratory, a secret laboratory on a mesa in New Mexico where atomic bombs would be designed and built. An offer was made to the Princeton team to be redeployed there. "Like a bunch of professional soldiers," Wilson later recalled, "we signed up, en masse, to go to Los Alamos."[1] Like many other young physicists, Feynman soon fell under the spell of the charismatic Oppenheimer. His wife moved to a sanitorium in Albuquerque, as she had tuberculosis.

At Los Alamos, Feynman was assigned to Hans Bethe's Theoretical (T) Division, and impressed Bethe enough to be made a group leader. He and Bethe developed the Bethe–Feynman formula for calculating the yield of a fission bomb, which built upon previous work by Robert Serber.[2] As a junior physicist, he was not central to the project. He administered the computation group of human computers in the theoretical division. With Stanley Frankel and Nicholas Metropolis, he assisted in establishing a system for using IBM punched cards for computation.

Other work at Los Alamos included calculating neutron equations for the Los Alamos "Water Boiler", a small nuclear reactor, to measure how close an assembly of fissile material was to criticality.

On completing this work, Feynman was sent to the Clinton Engineer Works in Oak Ridge, Tennessee, where the Manhattan Project had its uranium enrichment facilities. He aided the engineers there in devising safety procedures for material storage so that criticality accidents could be avoided, especially when enriched uranium came into contact with water, which acted as a neutron moderator. Putting himself at odds, with General Groves, the project director, he insisted on giving the rank and file a lecture on nuclear physics so that they would realize the dangers. He explained that while any amount of unenriched uranium could be safely stored, the enriched uranium had to be carefully handled. He developed a series of safety recommendations for the various grades of enrichments. He was told that if the people at Oak Ridge gave him any difficulty with his proposals, he was to inform them that Los Alamos "could not be responsible for their safety otherwise".

At Los Alamos, Feynman amused himself by investigating the combination locks on the cabinets and desks of physicists. He often found that they left the lock combinations on the factory settings, wrote the combinations down, or used easily guessable combinations like dates. He found one cabinet's combination by trying numbers he thought a physicist might use (it proved to be 27–18–28 after the base of natural logarithms, e = 2.71828 ...), and found that the three filing cabinets where a colleague kept research notes all had the same combination. He left notes in the cabinets as a prank, spooking his colleague, Frederic de Hoffmann, into thinking a spy had gained access to them.

Feynman's $380 (equivalent to $7,000 in 2023) monthly salary was about half the amount needed for his modest living expenses and his ailing wife Arline's medical bills, and they were forced to dip into her $3,300 (equivalent to $58,000 in 2023) in savings. On weekends, he borrowed a car from his friend Klaus Fuchs to drive to Albuquerque to see Arline. Asked who at Los Alamos was most likely to be a spy, Fuchs mentioned Feynman's safe-cracking and frequent trips to Albuquerque; Fuchs himself later confessed to spying for the Soviet Union. The FBI would compile a bulky file on Feynman, particularly in view of Feynman's Q clearance.

Informed that Arline was dying, Feynman drove to Albuquerque and sat with her for hours until she died on June 16, 1945. He then immersed himself in work on the project and was present at the Trinity nuclear test. Feynman claimed to be the only person to see the explosion without the very dark glasses or welder's lenses provided, reasoning that it was safe to look through a truck windshield, as it would screen out the harmful ultraviolet radiation. The immense brightness of the explosion made him duck to the truck's floor, where he saw a temporary "purple splotch" afterimage.

## References[edit]

1. ↑ Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320. p 59.
2. ↑ Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. p 183.

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