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

He had had other worries: just months before, Gweneth had herself undergone surgery for cancer. Feynman’s tumor pushed his intestines aside and destroyed his left kidney, his left adrenal gland, and his spleen.

It was a rare cancer of the soft fat and connective tissue, a myxoid liposarcoma. After difficult surgery, he left the hospital looking gaunt and began a search of the medical literature. There he found no shortage of probabilistic estimates. The likelihood of a recurrent tumor was high, though his had appeared wel encapsulated. He read a series of individual case studies, none with a tumor as large as his. “Five-year survival rates,” one journal said in summary, “have been reported from 0% to 11%, with one report of 41%.” Almost no one survived ten years.

He returned to work. “You are old, Father Feynman,”

wrote a young friend in a mocking bit of verse,

“And your hair has turned visibly gray;

And yet you keep tossing ideas around—

At your age, a disgraceful display!”

“In my youth,” said the Master, as he shook his long locks,

“I took a great fancy to sketching;

I drew many diagrams, which most thought profound

While others thought just merely fetching.”

“Yes, I know,” said the youth, interrupting the sage,

“That you once were so awful y clever;

But now is the time for quark sausage with chrome.

Do you think you can last on forever?”

Younger physicists, including Gel -Mann, had already stepped aside from the research frontier, but Feynman turned to problems in quantum chromodynamics—the latest synthesis of field theories, so named because of the central role of quark color. With a postdoctoral student, Richard Field, he studied the very-high-energy details of quark jets.

Other theorists had realized that the reason quarks never emerged freely was that they were confined by a force unlike those with which physics was familiar. Most forces diminished with distance—gravity and magnetism, for example. It seemed obvious that this must be so, but the opposite was true for quarks. When they were close together, the force between them was negligible; when they were drawn apart, the force grew extremely strong. Jets, as Feynman and Field understood them, were a by-product. In a high-energy col ision, before a quark could be broken free of these bonds, the force would become so great that it

would create new particles, pul ing them into existence out of the vacuum in a burst traveling in the same direction—a jet.

At first Field met with Feynman one afternoon a week.

Feynman did not realize that Field was spending almost every waking hour preparing for their meeting. Their work took the form of predictions in a language wel suited to experimenters. It was not abstruse theory but a realistic guide to what experimenters should see. Feynman insisted that they calculate only experiments that had not yet been performed; otherwise, he said, they would not be able to trust themselves. Gradual y they found that they were able to stay a few months ahead of the experiments and provide a useful framework. As the accelerators reached higher energies, jets of the kind Feynman and Field had described came into existence.

Theorists meanwhile continued to struggle with their understanding of quark confinement: whether quarks must always be confined under every circumstance and whether confinement could be derived natural y from the theory.

Victor Weisskopf urged Feynman to work on this, too, by saying that al he could see in the literature was formal mathematics. “I don’t get any physics out of it. Why don’t you attack the problem? You are just the right guy for it and you would find the essential physical reasons why QCD

confines the quarks.” Feynman made an original effort in 1981 to solve this problem analytical y in a toy model of two dimensions. Quantum chromodynamics, as he noted, had become a theory of such internal complexity that usual y

even the fastest supercomputers could not generate specific predictions to compare with experiments. “QCD

field theory with six flavors of quarks with three colors, each represented by a Dirac spinor of four components, and with eight four-vector gluons, is a quantum theory of amplitudes for configurations each of which is 104 numbers at each point in space and time,” he wrote. “To visualize al this qualitatively is too difficult.” So he tried removing a dimension. This turned out to be a blind al ey, although the freshness of his approach kept the work on some theorists’

reading lists long after they had passed by its conclusions.

In September 1981 a tumor recurred, this time entwined about Feynman’s intestines. The doctors tried a combination of doxorubicin, radiation treatment, and heat therapy. Then he underwent his second major surgery. The radiation had left his tissues spongy. The surgery lasted fourteen and a half hours and involved what the physicians described euphemistical y as a “vascular incident”—his aorta split. An emergency request for blood went out at Caltech and the Jet Propulsion Laboratory, and donors lined up. Feynman needed seventy-eight pints. When Caltech’s president, Marvin Goldberger, entered his hospital room afterward, Feynman said, “I’d rather be where I am than where you are” and added that he stil was not going to do anything Goldberger asked. In visible pain, he entertained his hospital visitors with new stories. Before the operation, the surgeon, Donald Morton of the UCLA Medical Center, had appeared with a halo of residents and nurses. Feynman asked what his chances were. “It’s

impossible to talk about the probability of a single event,”

he recounted the surgeon as saying, and he replied, “From one professor to another, it is possible if it’s a future event.”

Caltech’s influence in physics had waned. It drew the same extraordinary col ection of bright, naïve, gangly undergraduates, al assuming that they would be taking graduate courses by their junior years. The best graduate students, however, went elsewhere. The physics col oquium remained an institution—Feynman usual y sitting like a magnet in the front row, capable of dominating every session, visitors knew, entertainingly or ruthlessly. He could reduce an unwary speaker to tears. He shocked col eagues by tearing the flesh off an elderly Werner Heisenberg, made the young relativist Kip Thorne physical y il —the stories reminded older physicists of Pauli (“ ganz falsch ”). Douglas Hofstadter, a pioneer in artificial intel igence, gave an unusual talk on the slippery uses of analogy. He began by asking the audience to name the First Lady of England, looking for such answers as Margaret Thatcher, Queen Elizabeth, or Denis Thatcher. “My wife,” came the cry from the front row. Why? “Because she’s English and she’s great.” Through the rest of his talk, it seemed to Hofstadter that Feynman continued heckling in the manner of the vil age idiot. He was no less an institution than ever, but the center of gravity of elementary particle physics had drifted eastward again, toward Harvard and Princeton and other universities. A combined theory of electromagnetism and weak interactions had led to the gauge theories that brought together the strong interactions under the same

quantum-chromodynamical umbrel a. This resurgence of quantum theory also brought a new appreciation of Feynman’s path integrals, because path integrals proved essential in quantizing the gauge theories. Feynman’s discovery now seemed not just a useful tool but an organizing principle at nature’s deepest levels. Yet he did not pursue the new implications of path integrals himself. At the forefront were such theorists as Steven Weinberg, Abdus Salam, Sheldon Glashow, and younger col eagues who had seen neither Feynman nor Gel -Mann as the magnets they had once been. Caltech physicists, concerned about the loss of their department’s preeminence, sometimes blamed Feynman for not involving himself enough in hiring and Gel -Mann for involving himself too much.