Джеймс Глик - Genius - The Life and Science of Richard Feynman

Physics was stil a young science, more obscure than any human knowledge to date, yet stil something of a family business. Its written record remained smal , even as whole new scientific frameworks—nuclear physics, quantum field theory—were being born. The literature sustained just a handful of journals, stil mostly in Europe. Richard knew nothing of these.

Across town, another precocious teenager, named Julian Schwinger, had quietly inserted himself into the world of the new physics. He was already as much a creature of the city as Feynman was of the city’s outskirts: the younger son of a wel -to-do garment maker, growing up in Jewish Harlem and then on Riverside Drive, where dark, stately apartment buildings and stone town houses fol owed the curve of the Hudson River. The drive was built for motor traffic, but truck horses stil pul ed loads of boxes to the merchants of Broadway, a few blocks east. Schwinger knew how to find

books; he often prowled the used-book stores of lower Fourth and Fifth Avenues for advanced texts on mathematics and physics. He attended Townsend Harris High School, a national y famous institution associated with the City Col ege of New York, and even before he entered City Col ege, in 1934, when he was sixteen, he found out what physics was—the modern physics. With his long, serious face and slightly stooped shoulders he would sit in the col ege’s library and read papers by Dirac in the Proceedings of the Royal Society of London or the Physikalische Zeitschrift der Sowjetunion . He also read the Physical Review , now forty years past its founding; it had advanced from monthly to biweekly publication in hopes of competing more nimbly with the European journals. Schwinger struck his teachers as intensely shy. He carried himself with a premature elegant dignity.

That year he careful y typed out on six legal-size sheets his first real physics paper, “On the Interaction of Several Electrons,” and the same elegance was evident. It assumed for a starting point the central new tenet of field theory: “that two particles do not interact directly but, rather the interaction is explained as being caused by one of the particles influencing the field in its vicinity, which influence spreads until it reaches the second particle.” Electrons do not simply bounce off one another, that is. They plow through that magnificent ether substitute, the field; the waves they make then swish up against other electrons.

Schwinger did not pretend to break ground in this paper.

He showed his erudition by adopting “the quantum

He showed his erudition by adopting “the quantum electrodynamics of Dirac, Fock, and Podolsky,” the

“Heisenberg representation” of potentials in empty space, the “Lorentz-Heaviside units” for expressing such potentials in relatively compact equations. This was heavy machinery in soft terrain. The field of Maxwel , which brought electricity and magnetism together so effectively, now had to be quantized, built up from finite-size packets that could be reduced no further. Its waves were simultaneously smooth and choppy. Schwinger, in his first effort at professional physics, looked beyond even this difficult electromagnetic field to a more abstract field stil , a field twice removed from tangible substance, buoying not particles but mathematical operators. He pursued this conception through a sequence of twenty-eight equations. Once, at equation 20, he was forced to pause. A fragment of the equation had grown unmanageable—infinite, in fact. To the extent that this fragment corresponded to something physical, it was the tendency of an electron to act on itself. Having shaken its field, the electron is shaken back, with (so the mathematics insisted) infinite energy. Dirac and the others had grudgingly settled on a response to this difficulty, and Schwinger handled it in the prescribed manner: he simply discarded the offending term and moved on to equation 21.

Julian Schwinger and Richard Feynman, exact contemporaries, obsessed as sixteen-year-olds with the abstract mental world of a scientist, had already set out on different paths. Schwinger studying the newest of the new physics, Feynman fil ing schoolboy notebooks with standard mathematical formulas, Schwinger entering the

arena of his elders, Feynman stil trying to impress his peers with practical jokes, Schwinger striving inward toward the city’s intel ectual center, Feynman haunting the beaches and sidewalks of its periphery—they would hardly have known what to say to each other. They would not meet for another decade; not until Los Alamos. Long afterward, when they were old men, after they had shared a Nobel Prize for work done as rivals, they amazed a dinner party by competing to see who could most quickly recite from memory the alphabetical headings on the spines of their half-century-old edition of the Encyclopaedia Britannica .

As his childhood ended, Richard worked at odd jobs, for a neighborhood printer or for his aunt, who managed one of the smal er Far Rockaway resort hotels. He applied to col eges. His grades were perfect or near perfect in mathematics and science but less than perfect in other subjects, and col eges in the thirties enforced quotas in the admission of Jews. Richard spent fifteen dol ars on a special entrance examination for Columbia University, and after he was turned down he long resented the loss of the fifteen dol ars. MIT accepted him.

MIT

A seventeen-year-old freshman, Theodore Welton, helped some of the older students operate the wind-tunnel display at the Massachusetts Institute of Technology’s Spring Open House in 1936. Like so many of his classmates he had arrived at the Tech knowing al about airplanes, electricity, and chemicals and revering Albert Einstein. He was from a smal town, Saratoga Springs, New York. With most of his first year behind him, he had lost none of his confidence.

When his duties ended, he walked around and looked at the other exhibits. A miniature science fair of current projects made the open house a showcase for parents and visitors from Boston. He wandered over to the mathematics exhibit, and there, amid a crowd, his ears sticking out noticeably from a very fresh face, was what looked like another first-year boy, inappropriately taking charge of a complex, suitcase-size mechanical-mathematical device cal ed a harmonic analyzer. This boy was pouring out explanations in a charged-up voice and fielding questions like a congressman at a press conference. The machine could take any arbitrary wave and break it down into a sum of simple sine and cosine waves. Welton, his own ears burning, listened while Dick Feynman rapidly explained the workings of the Fourier transform, the advanced mathematical technique for analyzing complicated wave

forms, a piece of privileged knowledge that Welton until that moment had felt sure no other freshman possessed.

Welton (who liked to be cal ed by his initials, T. A.) already knew he was a physics major. Feynman had vacil ated twice. He began in mathematics. He passed an examination that let him jump ahead to the second-year calculus course, covering differential equations and integration in three-dimensional space. This stil came easily, and Feynman thought he should have taken the second-year examination as wel . But he also began to wonder whether this was the career he wanted. American professional mathematics of the thirties was enforcing its rigor and abstraction as never before, disdaining what outsiders would cal “applications.” To Feynman—having final y reached a place where he was surrounded by fel ow tinkerers and radio buffs—mathematics began to seem too abstract and too far removed.

In the stories modern physicists have made of their own lives, a fateful moment is often the one in which they realize that their interest no longer lies in mathematics.