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

“Oppenheimer’s formula … is remarkably correct for him, apparently only the numerical factor is wrong,” a theoretician once wrote acidly. In later physicist lingo a calculation’s Oppenheimer factors were the missing π’s, i ’s, and minus signs. His physics was, as the historian Richard Rhodes commented, “a physics of bank shots”—“It works the sides and the corners … but prefers not to drive relentlessly for the goal.” No one understood the core problems of quantum electrodynamics and elementary particle physics better than he, but his personal work tended toward esoterica. As a result, though he became the single most influential behind-the-scenes voice in the

awarding of Nobel Prizes in physics, he never received one himself. In science as in al things he had the kind of taste cal ed exquisite. His suits were tailored with exaggerated shoulders and broad lapels. He cared about his martinis and black coffee and pipe tobacco. Presiding over a committee dinner at a steak house, he expected his companions to fol ow his lead in specifying rare meat; when one man tried to order wel -done, Oppenheimer turned and said considerately, “Why don’t you have fish?” His New York background was what Feynman’s mother’s family had striven toward and fal en back from; like Lucil e Feynman he had grown up in comfortable circumstances in Manhattan and attended the Ethical Culture School. Then, where Feynman assimilated the new, pragmatic, American spirit in physics, Oppenheimer had gone abroad to Cambridge and Göttingen. He embraced the intel ectual European style. He was not content to master only the modern languages. To physicists Oppenheimer’s command of Sanskrit seemed a curiosity; to General Groves it was another sign of genius. And genius was what the general sought. Solid administrator that he was, he saw no value in a merely solid chief scientist. Much to the surprise of some, Groves’s instincts proved correct. Oppenheimer’s genius was in leadership after al . He bound Feynman to him in the winter of early 1943, as he bound so many junior col eagues, taking an intimate interest in their problems. He cal ed long-distance from Chicago—Feynman had never had a long-distance telephone cal from so far—to say that he had found a sanatorium for Arline in Albuquerque.

In the choice of a site for the atomic bomb project, the army’s taste and Oppenheimer’s coincided. Implausible though it may have seemed afterward, military planning favored desert isolation for security against enemy attack as wel as more reasonably for the quarantine of a talkative and unpredictable scientific community. Oppenheimer had long before fal en in love with New Mexico’s unreal edges, the air clear as truth, the stunted pines cleaving to canyon wal s. He had made Western work shirts and belt buckles part of his casual wear, and now he led Groves up the winding trail to the high mesa where the Los Alamos Ranch School for boys looked back across the wide desert to the Sangre de Cristo Mountains. Not everyone shared their immediate sympathy with the landscape. Leo Szilard, the Budapest native who first understood the energy-liberating chain reaction—at other times so prescient about the bomb project—declared: “Nobody could think straight in a place like that. Everybody who goes there wil go crazy.”

The impatient Princeton group signed up en masse.

Wilson rushed out to see the site and rushed back to report on the mud and confusion, a theater being built instead of a laboratory, water lines being mislaid. The state of secrecy was such that Feynman already knew that Groves and Oppenheimer were arguing over the state of secrecy.

Cyclotron parts and neutron-counting gear started heading out by rail in wooden crates from the Princeton station.

Princeton’s carloads provided the new laboratory’s core equipment, fol owed eventual y by a painstakingly dismantled cyclotron from Harvard and other generators

and accelerators. Soon Los Alamos was the best-equipped physics center in the world. The Princeton team began leaving soon after the crates of gear. Richard and Arline went with the first wave, on Sunday, March 28.

Instructions were to buy tickets for any destination but New Mexico. Feynman’s contrariety warred for a moment with his common sense, and contrariety won out. He decided that, if no one else was buying a New Mexico ticket, he would. The ticket sel er said, Aha—al these crates are for you?

The railroad provided a wheelchair and a private room for Arline. She had begged Richard tearful y to pay the extra price for the room and hinted that at last she might have a chance to be al that a wife should be to the husband she loves. For both of them the move out West portended an open-skied, open-ended future. It cut them off final y from their protective institutions and their childhoods. Arline cried night after night from worry and fil ed Richard with her dreams: curtains in their home, teas with his students, chess before the fireplace, the Sunday comics in bed, camping out in a tent, raising a son named Donald.

Chain Reactions

Fermi’s pile of uranium and graphite, sawed and assembled by professional cabinetmakers in a University of Chicago racquets court, became the world’s first critical mass of radioactive material on December 2, 1942. Amid

the black graphite bricks, the world’s first artificial chain reaction sustained itself for half an hour. It was a slow reaction, where a bomb would have to be a fast reaction—

less than a mil ionth of a second. From the two-story-high el ipsoid of Chicago pile number one to the basebal -size sphere of plutonium that exploded at Trinity, there could be no smooth evolutionary path. To go from the big, slow pile to a smal , fast bomb would require a leap. There were few plausible intermediate stages.

Yet one possibility was playing itself out in Feynman’s mind the next April, as he sat in a car just outside the makeshift security gate on the Los Alamos mesa.

Hydrogen atoms slowed neutrons, as Fermi had discovered ages ago. Water was cheaply bound hydrogen.

Uranium dissolved in water could make a powerful compact reactor. Feynman waited while the military guards tried to straighten out a mistake about his pass. Left and right from the security gate stretched the beginnings of a barbed-wire fence. Behind it lay no laboratory, but a few ranch buildings and a handful of partial y complete structures rose from the late-winter mud in what the army cal ed modified mobilization style, namely fast-setting concrete foundations, wood frame, plain siding, asphalt roofs. The thirty-five-mile ride from Santa Fe had ended in a harrowing dirt road cut bluntly into the mesa wal s.

Feynman was not the only physicist who had never been farther west than Chicago. The recruiters had warned scientists that the army wanted isolation, but no one quite realized what isolation would mean. At first the only

telephone link was a single line laid down by the Forest Service. To make a cal one had to turn a crank on the side of the box.

As he sat waiting for the military police to approve his pass, Feynman was running through some calculations for the hypothetical in-between reactor that would be cal ed a water boiler. Instead of blocks of uranium interspersed with graphite, this unit would use a uranium solution in water, uranium enriched with a high concentration of the 235

isotope. The hydrogen in the water would increase the effectiveness many times over. He was trying to figure out how much uranium would be needed. He worked on the water-boiler problem, picking it up and putting it down again over the next weeks, thinking about the detailed geometry of neutrons col iding in hydrogen. Then he tried something quirky. Perhaps the ideal arrangement of uranium, the one that would require the least material, would be different from the obvious uniform arrangement.