Quantum Man: Richard Feynman's Life in Science (15 page)

For many years, right up to and including the time, in 1965, when he was awarded the Nobel Prize for his work, Feynman felt that his methods were merely useful, not profound. He had not unveiled fundamental new properties of nature that would rid the theory of infinities, but had found a way to safely ignore them. The real hope—that path integrals would produce the revelations in our basic understanding of nature that he had hoped would cure the ills of relativistic quantum physics—he felt, had not materialized. As he said to a student newspaper on the day the Nobel Prize was announced, “It was the purpose of making these simplified methods of calculating more available that I published my paper in 1949, for I still didn’t think I had solved any real problems. . . . I was still expecting that I would some day come through the other end of my original idea . . . and get finite answers, get that self-radiation out and the vacuum circles and that stuff straightened out . . . which I never did.” And as he later described it in his Nobel address: “This completes the story of the development of the space-time view of quantum electrodynamics. I wonder if anything can be learned from it. I doubt it.”

History would ultimately prove otherwise.

PART II

The Rest of the Universe

Today we cannot see whether Schrödinger’s equation contains frogs, musical composers, or morality—or whether it does not. We cannot say whether something beyond it like God is needed, or not. And so we can all hold strong opinions either way.

—R
ICHARD
F
EYNMAN

CHAPTER
11

Matter of the Heart and
the Heart of Matter

What I am trying to do is bring birth to clarity, which is really a half-assedly thought-out pictorial semi-vision thing.

—R
ICHARD
F
EYNMAN

R
ichard Feynman did not lay down his sword in 1949. He had achieved something wonderful, but even he didn’t realize its full extent. In the meantime, nature continued to beckon. And for Feynman, being interested in physics meant being intensely curious about
all
aspects of the physical world, not just a single exciting frontier. The completion of his magnum opus on QED also coincided with a more personal and more difficult transition for him, from his beloved Cornell to the excitement and allure of more exotic climes.

As unconventional as Feynman was in his behavior and his way of dealing with social norms, he remained in those postwar years strangely provincial. I have already mentioned his early disinterest in classical music and the arts. And while he might have seemed worldly, largely through his wartime experience and his dealings with colleagues from other countries, by the age of thirty-one he had never ventured outside the shores of the continental United States. That would soon change.

Feynman’s mind was always searching for new problems and new intellectual challenges. This predilection crept into his personal life as well. He once said to me, “One should seek out new adventures wherever one can.”

I suspect that after the intense effort between 1946 and 1950 wrestling with QED, Feynman’s mind now wanted to move far afield, not just in topic, but in style. Emotionally restless and unhappy, and yearning for adventure, Feynman wanted to escape the confines of gloomy wintery Ithaca, and perhaps the many tense sexual entanglements he had gotten embroiled in. Sunny California beckoned, but South America seemed even more enticing.

Like many key life decisions, this one involved a bit of serendipity. An old Los Alamos colleague, Robert Bacher, was moving to Pasadena, to rebuild a dormant physics program at Caltech, and he immediately thought of Feynman. He called him at the right time. The man who had previously turned down Princeton, University of Chicago, Berkeley, and a host of other institutions agreed to visit Pasadena. At the same time, Feynman’s imagination was drifting even further. He had decided, for some reason, to visit South America, and had started to learn Spanish when a visiting Brazilian physicist invited him to Brazil for the summer of 1949. Feynman quickly accepted, got a passport, and switched to learning Portuguese.

He lectured on physics at the Centro Brasiliero de Pesquisas Fisicas in Rio de Janeiro and returned to Ithaca in the fall, more knowledgeable about Portuguese and the ways of Brazilians, thanks to a Copacabana beauty, or
garota,
named Clotilde, whom he had persuaded to accompany him back to the United States for a short while. The winter in Ithaca convinced him that he had to leave, and Caltech, in addition to better weather, had the appeal of not being a liberal arts university like Cornell, where, he said, “the theoretical broadening which comes from having many humanities subjects on campus is offset by the general dopiness of the people who study these things.” He accepted the offer from Caltech and negotiated a deal that gave him the best of all possible worlds. He could take an immediate sabbatical year and head back to his beloved Brazil, where he could keep in touch with physics while swimming off the Copacabana beach and frolicking at night, all courtesy of Caltech and with support from the U.S. State Department.

His prime interest during this time was in the newly discovered mesons, and the confusion they introduced into nuclear physics. He used a ham radio as well as letters to contact his colleagues in the United States, and ask them questions, or issue advice. Fermi chided him: “I wish I could also refresh my ideas by swimming off Copacabana.”

But Feynman also took seriously his own mission of helping to rejuvenate physics in Brazil. He taught courses at the Centro Brasileiro de Pesquisas Fisícas and chastised the Brazilian authorities for teaching students to memorize names and formulas but not to think about what they were doing. He complained they were learning how to explain words in terms of other words, but actually understood nothing and had no feel for the actual phenomena they were supposedly studying. For Feynman, understanding meant being able to take one’s knowledge and apply it to new situations.

As brilliant as Feynman was, though, the isolation in Brazil kept him from keeping up with the forefront of the field at the time. He managed to independently reproduce results that had already been derived, but did not push the emerging field of particle physics forward. Instead, he had a cultural awakening and a sexual feast.

First, music. Feynman claimed he was tone-deaf, but there is no doubt, even if he marched to the beat of a different drummer, that he was born with rhythm. All those who were close to him knew that he was constantly drumming with his fingers whenever he worked, on paper, on walls, on anything that was convenient. In Rio, Feynman found the perfect music for his psyche—samba, a hot, rhythmic, and unpretentious hybrid of Latin and African traditions. He joined a samba school and began drumming in samba bands. He even got paid for his efforts. The peak occurred during the annual Carnaval, a debauched street festival, where he could carouse with abandon. And carouse he did. (Purely by coincidence I am writing this as I stare out from a hotel at Copacabana beach.)

It is easy to understand the fascination Rio had for Feynman. The city is breathtakingly beautiful, surrounded by gorgeous mountain and ocean scenery, and vibrant with the Rio
cariocas
, locals occupied with partying, arguing, playing soccer, and flirting on the beach. The full spectrum of human activity is almost always on display. The city is seedy, sexy, intense, scary, friendly, and relaxed, all at the same time. There Feynman could escape the confinement of a university town, where one could never quite get away from colleagues or students. Moreover, the Brazilians are a warm, friendly, and accepting people. Feynman could blend in. His own intense enthusiasm, never far from the surface, must have resonated with everyone around him—physicists, local
cariocas
, and, naturally, women.

Feynman lived at the Miramar Palace Hotel on Copacabana beach, where he descended into his lonely orgy of drinking (until he frightened himself enough to swear off alcohol for good) and sex. He picked up women on the beach and in clubs and at the hotel’s patio bar, whose proximity to the action of Copacabana was, and still is, addictive. For a while he specialized in stewardesses who stayed at the hotel, and as he famously described over and over again, he enjoyed outsmarting the local women he met in bars. He convinced one of them not only to sleep with him, but also to repay him for the food he had bought her at the bar.

As often happens, however, this anonymous sex, while diverting, only reinforced his detached loneliness, and perhaps that is why he committed an utterly ridiculous and out-of-character act. He proposed, by letter, to a woman in Ithaca he had known and dated, a woman so different from the rest, and so different from Feynman, that perhaps he convinced himself she was the perfect complement.

Many of his previous girlfriends realized that the mutual enjoyment they thought they were sharing with Feynman was not being fully reciprocated. Feynman could concentrate completely on a woman he was with, in a way that was utterly captivating. But at the same time, as intense as his physical participation might have seemed, he was really alone with his thoughts. Mary Louise Bell, not savvy to this flaw, apparently pursued him from Ithaca to Pasadena. A platinum blonde with a penchant for high heels and tight clothes, she somehow thought that with Feynman she had the scaffolding from which she could fashion a final structure to her liking, one with a more polished exterior and a better appreciation of the arts, and one who wouldn’t hang around with so many scientists.

They married in 1952. With hindsight some have said that divorce was inevitable, but there are no real rules from which one can make accurate predictions in matters of the heart. Nevertheless, one of the items brought up in the divorce proceedings was telling. She reported, “He begins working calculus problems in his head as soon as he awakens. He did calculus while driving his car, while sitting in the living room and while lying in bed at night.”

During the first years together, as he settled into Pasadena following his wild year in Brazil, and his domestic bliss slowly turned into another private hell, he began to think he had made a mistake not only in choice of companion, but in choice of locale. He even wrote to Hans Bethe to discuss moving back to Cornell. But Caltech’s lure was greater than Mary Louise’s, and four years after their marriage, in 1956, he and Mary Louise parted ways, but he remained in Pasadena.

His new university was quickly growing to become a rival to his own eastern alma mater, MIT. It was an institution that, with its growing experimental and theoretical prominence in fields ranging from astrophysics to biochemistry and genetics, combined with the practical leanings of an engineering school, seemed like a perfect fit. It was. He would stay for the rest of his life.

Physics was experiencing a period of turmoil at the same time as Feynman’s personal upheavals. Newly discovered elementary particles, mesons and the like, were proliferating madly in the newly built particle accelerators. The elementary particle physics zoo was becoming embarrassingly crowded, so crowded in fact that it wasn’t clear which of the new blips on chart recorders and new tracks in bubble chambers might really represent new elementary particles and which were simply rearrangements of existing ones.

While Feynman had dabbled early on in the theory of mesons when he was perfecting his understanding of QED, he was also smart enough and realistic enough to know that his new diagrammatic methods were inappropriate to the task at hand. Not only were many of the experiments inconclusive, but the interactions between particles were generally so strong that the systematic effort to use Feynman diagrams to calculate small quantum corrections to processes seemed misplaced. He wrote to Enrico Fermi from Brazil: “Don’t believe any calculation in meson theory that uses a Feynman diagram!” Elsewhere he referred to the field of meson physics by saying, “Perhaps there aren’t enough clues for even a human mind to figure out what is the pattern.”

I suspect that, in his view, the experimental world of mesons wasn’t yet ready for interpretation, and he had a desire to strike out in a new intellectual direction, one that wasn’t governed so much by attempting to unravel the mathematical intricacies of the quantum world as much as directly trying to puzzle out its physical consequences. He wanted to think about something he could feel and play with, and not something he could only see in his mind. Thus, shortly after arriving at Caltech, Feynman turned to a completely different problem in a different area of physics. He began to explore not the quantum world of the very small, but the very cold.

The Dutch physicist Kamerlingh Onnes, who worked during the end of the nineteenth and early twentieth centuries, devoted his entire professional life to the physics of the very cold, cooling down systems closer and closer to absolute zero, the temperature where, classically at least, all internal motions of atoms would stop. In so doing, he made a miraculous discovery in 1911. At a temperature of 4 degrees above absolute zero (Onnes eventually got to less than 1 degree above absolute zero, reaching the coldest temperature ever achieved on earth up to that time), he witnessed a spectacular transition in mercury, in which electrical currents suddenly appeared to flow without any resistance at all.

It had been speculated that electrical resistance would decrease at very low temperatures, based on the simple observation that such a decrease was also observed at higher temperatures. Onnes himself speculated that the resistance would drop to zero at absolute zero, a temperature that can never be obtained directly in the laboratory. However, his amazing result was that the resistance abruptly dropped to exactly zero at a finite small, but nonzero, temperature. In such a state, an electric current, once started, would never stop. Onnes had discovered the phenomenon he called
superconductivity
.

Interestingly, when Onnes won the Nobel Prize two years later, he did not win it explicitly for this discovery, but rather for his general “investigations on the properties of matter at low temperatures which led, inter alia, to the production of liquid helium.” The prize showed unusual prescience (actually dumb luck) on the part of the Nobel Committee because it turned out, for reasons no one could have suspected in 1913, that liquid helium itself had properties at least as fascinating as those related to the conductivity of mercury and other metals at low temperatures. In 1938 it was discovered that liquid helium, when cooled sufficiently, exhibits a phenomenon known as
superfluidity
, which on its surface seems even stranger than superconductivity. Again, equally remarkably, Onnes probably cooled liquid helium to temperatures where it was superfluid, but didn’t remark on this otherwise remarkable phenomenon.

In its superfluid phase, helium flows with no friction whatsoever. Put it in a container, and it will spontaneously flow in a thin film up over its edges. No matter how small a crack, it will flow through it. Unlike superconductivity, where the magic is hidden behind resistance and current measurements, with superfluidity it is on full display before our eyes.

As late as the early 1950s neither of these remarkable phenomena had yet been explained in terms of a microscopic atomic theory. As Feynman put it, they were like “two cities under siege . . . completely surrounded by knowledge although they themselves remained isolated and unassailable.” At the same time, he was enamored with all of the fascinating new phenomena that nature revealed at low temperatures, and said, “I imagine experimental physicists must often look with envy at men like Kamerlingh Onnes, who discovered a field like low temperature, which seems to be bottomless and in which one can go down and down.” Feynman was fascinated by all of these phenomena, but he turned his attention primarily to the mysteries of liquid helium, although he continued to struggle, ultimately unsuccessfully, to unravel the origin of superconductivity.