Nambu, Yoichiro (1921-2015), a Japanese-born American physicist, won a share of the 2008 Nobel Prize in physics. Nambu won for his explanation of broken symmetry, an important property of subatomic particles. Subatomic particles are pieces of matter smaller than atoms. Nambu shared the prize with two other physicists, Makoto Kobayashi and Toshihide Maskawa of Japan. Kobayashi and Maskawa identified the particles that must exist for Nambu’s broken symmetry theory to work.
In particle physics, scientists use the term symmetry to describe the idea that for every subatomic particle, there exists an opposite particle with similar properties. For example, the electron has the positron, a similar particle with an opposite electrical charge. However, scientists think that if such particle pairs shared a perfect symmetry, the universe could not exist as we know it. Thus, they thought that the particles must share a symmetry that is somehow incomplete or “broken.” But scientists were unsure how such broken symmetries could arise.
Beginning in the late 1950’s, Nambu was studying the behavior of electrons in superconductors, materials that conduct electrical current without resistance at low temperatures. He developed a mathematical description of their behavior that involved a broken symmetry. Nambu was able to show mathematically how this broken symmetry arose spontaneously (without external cause). In the early 1960’s, Nambu applied this idea to broken symmetries among the broader class of subatomic particles. He was able to show these broken symmetries can also arise spontaneously. Nambu’s work helped in the development of the Standard Model, the leading fundamental theory of physics that describes all the known basic subatomic particles and their interactions.
Nambu was born Jan. 18, 1921, in Tokyo. He received his Doctorate of Science degree from the University of Tokyo in 1952. He was a member of the Institute for Advanced Study in Princeton, New Jersey, from 1952 to 1954. He then moved to the University of Chicago and became a professor in 1956. Nambu died on July 5, 2015.
See also Kobayashi, Makoto ; Maskawa, Toshihide .
