Nov. 28, 1994
Vol. 14, No. 7

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    Nambu awarded Wolf Prize in physics

    Yoichiro Nambu, the Harry Pratt Judson Distinguished Service Professor Emeritus in Physics and the Enrico Fermi Institute and one of the leading figures in the development of modern particle physics, has been awarded the 1994-95 Wolf Prize in physics.

    Nambu will share the prestigious prize with Vitaly Ginzburg of the Lebedev Physical Institute in Moscow. The prize was announced Nov. 15 and will be awarded March 26 in Israel.

    Nambu was honored for his contributions to theoretical particle physics -- in particular, for the work he did to develop the concept of "spontaneous symmetry-breaking" in superconductivity and in the physics of fundamental particles. His theories form an essential cornerstone of what physicists call the Standard Model, which explains in a unified way three of the four fundamental forces of nature: strong, weak and electromagnetic. The award also recognizes his significant contributions to the "color gauge theory," which explains how the strong nuclear force governs the behavior of the quarks that make up protons and neutrons in atomic nuclei, and his contributions to String Theory, one of the dominant theories in physics today.

    Although Nambu said he was surprised to receive the award, his colleagues said he has long deserved this kind of recognition for his work.

    Nobel laureate James Cronin, University Professor in Physics, said, "This is wonderful news. He has always been way ahead of his time, to the point where what he discovered was thought to be discovered by other people much later."

    "He is one of the most remarkable people that I have ever met in how he works and how he thinks," said Peter Freund, Professor in Physics. "I see two types of physicists: there are those who think like you and me -- when they reach a new result you can follow the train of thought that led them to what they found -- and then there are those exceptional physicists like Nambu, Richard Feynman and Paul Dirac. Of course one understands what they ended up with, but at the same time, I don't know that I understand how on earth they came up with it.

    "Somewhere in the process there is always a rabbit pulled out of a hat -- and of course, it's a very exciting rabbit, a brilliant idea -- but where that rabbit came from, it's not ever clear. It's not, as Nambu modestly claims, a trivial consequence of building on things that came before."

    Nambu found the concept of spontaneous symmetry-breaking, or SSB, while studying superconductivity in the early 1960s. He said that it took him two years to figure out that SSB contributes to the explanation of how superconductivity works, but once he developed the theory, he quickly turned it around and applied it to particle physics.

    His theories predicted the existence of a number of massless fundamental particles -- a finding later confirmed by experimental observation.

    Freund described SSB using the analogy of a dinner table set for a banquet. "At a round dinner table, each place setting is symmetric. You have a napkin to the left and one to the right. If you are from a Western culture, you know that you are supposed to take the napkin to your left. But suppose you have dinner guests from another culture, and they don't know which one to take. If one of these guests reaches for a napkin, whether it's the napkin on the right or the one on the left, he determines the choice for everyone else at the table." Freund said that no matter whether there are five dinner guests or 10 billion, the consequences are the same. Once the symmetry has been broken, the long-range consequences extend to every other dinner guest at the table.

    Nambu's current research centers on why different quarks have different masses -- a consequence, physicists believe, of SSB. "Why quarks have different masses is one of the last unsolved puzzles of the Standard Model," Nambu said.

    And how does Nambu go about solving a problem like that? He answered, laughing, "I think about it all the time."

    The Wolf Prize, presented by the Israel-based Wolf Foundation, is awarded annually in the fields of agriculture, physics, chemistry, medicine, mathematics and the arts. The prize carries a monetary award of $100,000, which will be shared by Nambu and Ginzburg.

    Nambu was born in Tokyo in 1921 and received his B.S. in 1942 and his D.Sc. in 1952 from the University of Tokyo. He first came to the United States, to the Institute for Advanced Study, in 1952. He joined the University as Research Associate in 1954 and became Associate Professor in 1956 and Professor in 1958. He was named the Harry Pratt Judson Distinguished Service Professor in 1977 and served as Chairman of Physics from 1974 to 1977. He became emeritus in 1991. Nambu became a U.S. citizen in 1970.

    His previous honors include the National Medal of Science, the Dannie Heineman Prize for Mathematical Physics, the J. Robert Oppenheimer Prize and the Order of Culture from the government of Japan.