Advancing quantum mechanics—today the basis of advanced physics—and performing theoretical work manifest today in nanotechnology and computer technology
Richard Feynman
(1918–1988)
Richard Feynman was among the most famous scientists of his time, in part because of his disarming personality and his ability to popularize the most difficult of concepts. Once asked to explain quantum mechanics, he replied, “I think I can safely say that nobody understands quantum mechanics.” The response was more than witty, since it conveyed the very core of quantum theory, which is, in fact, beyond easy human understanding yet quite capable of mathematical expression. Thus, Feynman’s quip expressed the essence of modern physics.
If one asks physicists today to name Feynman’s greatest breakthroughs, the answers give bewildered non-scientists precious little satisfaction:
• The Feynman path integral, a breakthrough in quantum field theory, which seeks to unite and reconcile modern concepts of fields, Einstein’s theory of special relativity, and quantum mechanics in an effort to create a coherent physics.
• Feynman diagrams, which facilitate calculations in quantum mechanics—calculations that would otherwise be too technically difficult to carry out.
• Quantum electrodynamics, a quantum field theory of the interaction of light and matter, which won Feynman and his two co-creators the 1965 Nobel Prize for Physics.
• The parton model of hadrons, a breakthrough in understanding the complexity of the proton and thereby understanding particle physics, which is ultimately essential to understanding nature itself.
Quantum mechanics is a branch of physics that strikes not only non-scientists as alien, but was even too much for Albert Einstein to accept. It explores nature at its most fundamental levels, levels at which subatomic particles behave in very strange ways. They take on more than one state at the same time. They interact with other particles that are far away and seemingly unrelated and unconnected. This led Einstein to mockingly say that quantum mechanics dealt with “spooky action at a distance.” And yet, thanks in large part to Feynman’s work, today’s physicists see quantum mechanics as the royal road to an understanding of the universe. Computer scientists see it as a means of computing the most complex problems imaginable or, indeed, unimaginable. Nanotechnologists see it as a means of hitherto unimaginable innovation.
• • •
The man destined to venture into territory that even Einstein shunned was not raised in exotic, other-worldly circumstances and surroundings. He was born on May 11, 1918, in the borough of Queens, New York, to Jewish immigrants from Russia and Poland. Where many parents are annoyed by their children’s incessant questions, Melville Feynman encouraged his son to ask and ask more and, in particular, to challenge what most people accept as self-evident and beyond question. His mother, Lucille, instilled in him a sense of humor, which he carried throughout his life. This humble, ordinary family actually produced two world-class physicists, Richard and his sister, Joan.
Feynman’s habit of questioning everything led him to atheism early in life. He threw himself into engineering and science, winning the New York University Math Championship in high school. Atheist though he was, he found himself confronted by anti-Semitism when his first-choice school, Columbia University, refused to enroll him because the institution had already met its “Jewish quota.” He enrolled instead at the Massachusetts Institute of Technology (MIT), graduating in 1939 and then entering Princeton University, where he studied mathematics and physics under the likes of Albert Einstein, Wolfgang Pauli, and John von Neumann. His doctorate was awarded in 1942, with a dissertation that presented a novel approach to quantum mechanics. The prevailing picture of what was at the time an emerging field had been developed by the great British physicist James Clerk Maxwell (1831–1879) in terms of electromagnetic waves. Feynman rejected the wave approach and instead based his descriptive theory entirely on the interaction of particles in space and time.
During World War II, Feynman worked on the Manhattan Project. Although already beginning to make his mark as a theorist, he was also an exceedingly practical scientific “engineer.” It was Feynman who developed the computational systems for calculating neutron equations for nuclear reactors, an important aspect of the Manhattan Project’s early work. He also developed safety procedures for storing radioactive materials at the Army’s facility in Oak Ridge, Tennessee, one of two sprawling plants that produced the fissionable material for the first atomic bombs. In addition, Feynman developed theoretical background for a proposed uranium hydride bomb which, however, proved impractical.
Whatever else the Manhattan Project was, its Los Alamos, New Mexico, laboratory served as a forum and arena in which the era’s foremost physicists interacted. Feynman became a close friend of Niels Bohr, a giant of atomic theory, and of Robert Oppenheimer, the scientific director of the entire project. While Feynman found the Manhattan Project experience intellectually exhilarating, he was afflicted with depression and guilt after the atomic bombing of Hiroshima and Nagasaki. Nevertheless, he emerged from World War II as a hot commodity in American science. He stunned colleagues by turning down an offer from the Institute for Advanced Study in Princeton, academic home of Einstein and the mathematicians Kurt Gödel and John von Neumann. Instead, he joined Hans Bethe at Cornell University, where he was a professor of theoretical physics from 1945 to 1950. From here, he moved to the California Institute of Technology (Caltech) as professor of theoretical physics, where he taught for the rest of his career.
Feynman proved himself to be a great teacher, and, as his lectures were widely published in a series of popular books for a broad readership, he was nicknamed “The Great Explainer.” His December 1959 presentation at a meeting of the American Physical Society, “There’s Plenty of Room at the Bottom,” unfolded the feasibility of building structures atom by atom or molecule by molecule. At the time, this seemed the stuff of science fiction, but it soon became the basis of nanotechnology. His pioneering work in quantum computing produced similarly practical results, as Feynman became involved in building the first massively parallel computer—work that was continued by his son, Carl, a computer scientist. Richard Feynman envisioned applying quantum computing to the building of neural networks and elaborate physical simulations using cellular automata.
Feynman’s Caltech years saw groundbreaking work in quantum electrodynamics, which resulted in his sharing the 1965 Nobel Prize for Physics; the quantum behavior of superfluidity in supercooled liquid helium; a model of weak radioactive decay, which was crucial to the study of certain subatomic particles; and the parton model for analyzing high-energy hadron collisions. The quantum electrodynamics work, which involved the interaction of light and matter, prompted him to develop his Feynman diagrams, which he and others have used to calculate interactions between particles in space-time, especially between electrons and their antimatter counterparts, positrons. The diagrams presented an alternative to otherwise prohibitively complex calculations and have been applied by many other physicists to a wide range of problems, including theories of quantum gravity, string theory, and membrane theory (M-theory).
Feynman earned new public notice when he was appointed to the Rogers Commission, formed to investigate the causes of the 1986 Challenger Space Shuttle disaster. The booster exploded moments after it was launched from Cape Kennedy on January 28, 1986. By the time the commission was created, Feynman was already critically ill with two very rare forms of cancer (liposarcoma and Waldenström’s macroglobulinemia), and his physicians advised him not to undertake the arduous task of the investigation. Feynman, however, felt that it was his duty. He followed up on a suggestion from Dr. Sally Ride (an astronaut herself) that O-rings, which served as sealing gaskets between segments of the launch vehicle’s solid rocket boosters (SRBs), had not been tested at temperatures below 50°F. The morning of the launch was freezing—rare frigid conditions for central Florida, even in winter. Feynman concluded that the O-rings lost resilience in the unusual cold, a theory he dramatically demonstrated on live television by simply immersing O-ring material in a glass of ice water. The sample became visibly brittle. Feynman went on to point out flaws in NASA’s safety culture, arguing that agency leaders had failed to recognize that, for “a successful technology, reality must take precedence over public relations, for nature cannot be fooled.” Always the disruptor, Feynman was unafraid of stepping on institutional toes, even if some of those belonged to fellow scientists.
Richard Feynman died on February 15, 1988, after a failed attempt to treat his cancer surgically.