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

paved—Princeton before the war remained, as F. Scott Fitzgerald described it adoringly a generation earlier, “lazy and good-looking and aristocratic,” an outpost for New York, Philadelphia, and Southern society. Its faculty, though increasingly professional, was stil sprinkled with Fitzgerald’s “mildly poetic gentlemen.” Even the kindly genius who became the town’s most famous resident on arriving in 1933 could not resist a gibe: “A quaint ceremonious vil age,” Einstein wrote, “of puny demigods on stilts.”

Graduate students, on track to a professional world, were partly detached from the university’s more frivolous side.

The physics department in particular was moving decisively with the times. It had seemed to Feynman from a distance that

Princeton’s

physicists

were

disproportionately

represented in the current journals. Even so he had to adjust to a place which, even more than Harvard and Yale, styled itself after the great English universities, with courtyards and residential “col eges.” At the Graduate Col ege a “porter” monitored the downstairs entranceway.

The formality genuinely frightened Feynman, until slowly he realized that the obligatory black gowns hid bare arms or sweaty tennis clothes. The afternoon he arrived at Princeton in the fal of 1939, Sunday tea with Dean Eisenhart turned his edginess about social convention into anxiety. He dressed in his good suit. He walked through the door and saw—worse than he had imagined—young women. He could not tel whether he was supposed to sit. A voice behind him said, “Would you like cream or lemon in your tea, sir?” He turned and saw the dean’s wife, a famous lioness of Princeton society. It was said that when the

mathematician Carl Ludwig Siegel returned to Germany in 1935 after a year in Princeton he told friends that Hitler had been bad but Mrs. Eisenhart was worse.

Feynman blurted, “Both, please.”

“Heh-heh-heh-heh-heh,” he heard her say. “Surely you’re joking , Mr. Feynman!” More code—the phrase evidently signaled a gaffe. Whenever he thought about it afterward, the words rang in his ears: surely you’re joking. Fitting in was not easy. It bothered him that the raincoat his parents sent was too short. He tried scul ing, the Ivy League sport that seemed least foreign to his Far Rockaway experience

—he remembered the many happy hours spent rowing in the inlets of the south shore—and promptly fel from the impossibly slender boat into the water. He worried about money. When he entertained guests in his room they would share rice pudding and grapes, or peanut butter and jel y on crackers with pineapple juice. As a first-year teaching assistant he earned fifteen dol ars a week. Cashing several savings certificates to pay a bil for $265, he spent twenty minutes calculating what combination would forfeit the least interest. The difference between the worst case and the best case, he found, came to eight cents. Outwardly, though, he cultivated his brashness. Not long after he arrived, he had his neighbors at the Graduate Col ege convinced that he and Einstein (whom he had not met) were on regular speaking terms. They listened with awe to these supposed conversations with the great man on the pay phone in the hal way: “Yeah, I tried that … yeah, I did …

oh, okay, I’l try that.” Most of the time he was actual y speaking with Wheeler.

As Wheeler’s teaching assistant—first for a course in

mechanics, then in nuclear physics—Feynman quickly found himself taking over in the professor’s absence (and it began to sink in that facing a roomful of students was part of the profession he had chosen). He also met with Wheeler weekly on research problems of their own. At first Wheeler assigned the problems. Then a col aboration took shape.

The purview of physics had exploded in the first four decades of the century. Relativity, the quantum, cosmic rays, radioactivity, the nucleus—these new realms held the attention of leading physicists to the virtual exclusion of such classical topics as mechanics, thermodynamics, hydrodynamics, statistical mechanics. To a smart graduate student fresh on the theoretical scene these traditional fields seemed like textbook science, already part of history and—in their applied forms—engineering. Physics was

“inward bound,” as its chronicler Abraham Pais put it; into the core of the atom the theorists went. Al the superlatives were here. The experimental apparatus was the most expensive (machines could now cost thousands or even tens of thousands of dol ars). The necessary energies were the highest. The materials and “particles” (this word was acquiring a specialized meaning) were the most esoteric.

The ideas were the strangest. Relativity notoriously changed astronomers’ sense of the cosmos but found its most routine application in the physics of the atom, where near-light speeds made relativistic mathematics essential.

As experimenters learned to ply greater levels of energy, the basic constituents gave way to new units even more basic. Through quantum mechanics, physics had established a primacy over chemistry—itself formerly the

most fundamental of sciences, if the most fundamental was the one responsible for nature’s basic constituents.

As the thirties ended and the forties began, particle physics had not established its later dominance of the public relations of science. In choosing a theme for the annual Washington Conference on theoretical physics in 1940, organizers considered “The Elementary Particles”

and the quaintly geophysical “Interior of the Earth”—and chose the interior of the earth. Stil , neither Feynman nor Wheeler had any doubt about where a pure theorist’s focus must turn. The fundamental issue in the fundamental science was the weakness in the heart of quantum mechanics. At MIT Feynman had read Dirac’s 1935 text as a cliffhanger with the most thril ing possible conclusion: “It seems that some essential y new physical ideas are here needed.” Dirac and the other pioneers had taken their quantum electrodynamics—the theory of the interplay of electricity, magnetism, light, and matter—as far as they could. Yet it remained incomplete, as Dirac wel knew.

The difficulty concerned the electron, the fundamental speck of negative charge. As a modern concept, the electron was stil young, although many high-school students now performed (as Feynman had in Far Rockaway) a tabletop experiment showing that electric charge came in discrete units. What exactly was the electron? Wilhelm Röntgen, the discoverer of X rays, forbade the use of this upstart term in his laboratories as late as 1920. The developers of quantum mechanics, attempting to describe the electron’s charge or mass or momentum or energy or spin in almost every new equation, nevertheless maintained a silent agnosticism about certain

issues of its existence. Particularly troubling: Was it a finite pel et or an infinitesimal point? In his model of the atom, already obsolete, Niels Bohr had imagined electrons as miniature planetoids orbiting the nucleus; now the atom’s electron seemed more to reverberate in an oscil atory harmony. In some formulations it assumed a wavelike cloak, the wave representing a distribution of probabilities that it would appear in particular places at particular times.

But what would appear? An entity, a unit—a particle?

Even before quantum mechanics, a worm had gnawed at the heart of the classical understanding. The equations linking the electron’s energy (or mass) and charge implicated another quantity, its radius. As its size diminished, the electron’s energy grew, just as the pressure transmitted by a carpenter’s hammer becomes thousands of pounds per square inch when concentrated at the point of a nail. Furthermore, if the electron was to be imagined as a little bal of finite size, then what force or glue kept it from bursting from its own charge? Physicists found themselves manipulating a quantity cal ed the “classical electron radius.” Classical in this context came to mean something like make-believe . The problem was that the alternative—a vanishingly smal , pointlike electron—left the equations of electrodynamics plagued with divisions by zero: infinities.