Sheldon Lee Glashow

Sheldon Lee Glashow
Born (1932-12-05) December 5, 1932
New York City, New York, US
Nationality United States
Fields Theoretical Physics
Institutions Boston University
Harvard University
University of California, Berkeley
Alma mater Cornell University (BA)
Harvard University (PhD)
Thesis The vector meson in elementary particle decays (1958)
Doctoral advisor Julian Schwinger
Known for Electroweak theory
Georgi–Glashow model
Criticism of Superstring theory
Notable awards Nobel Prize in Physics (1979)
Spouse Joan Shirley Alexander (m. 1972; 4 children)

Sheldon Lee Glashow (/ˈɡlæʃoʊ/; born December 5, 1932) is a Nobel Prize winning American theoretical physicist. He is the Metcalf Professor of Mathematics and Physics at Boston University and Higgins Professor of Physics, Emeritus, at Harvard University, and is a member of the Board of Sponsors for the Bulletin of the Atomic Scientists.

Birth and education

Sheldon Lee Glashow was born in New York City, to Jewish immigrants from Russia, Bella (née Rubin) and Lewis Gluchovsky, a plumber.[1] He graduated from Bronx High School of Science in 1950. Glashow was in the same graduating class as Steven Weinberg, whose own research, independent of Glashow's, would result in the two and Abdus Salam sharing the same 1979 Nobel Prize in Physics (see below).[2] Glashow received a Bachelor of Arts degree from Cornell University in 1954 and a Ph.D. degree in physics from Harvard University in 1959 under Nobel-laureate physicist Julian Schwinger. Afterwards, Glashow became a NSF fellow at NORDITA and joined the University of California, Berkeley where he was an associate professor from 1962 to 1966.[3] He joined the Harvard physics department as a professor in 1966, and was named Higgins Professor of Physics in 1979; he became emeritus in 2000. Glashow has been a visiting scientist at CERN, and professor at the University of Marseilles, MIT, Brookhaven Laboratory, Texas A&M, the University of Houston, and Boston University.[2]

Research

In 1961, Glashow extended electroweak unification models due to Schwinger by including a short range neutral current, the Z0. The resulting symmetry structure that Glashow proposed, SU(2) × U(1), forms the basis of the accepted theory of the electroweak interactions. For this discovery, Glashow along with Steven Weinberg and Abdus Salam, was awarded the 1979 Nobel Prize in Physics.

In collaboration with James Bjorken, Glashow was the first to predict a fourth quark, the charm quark, in 1964. This was at a time when 4 leptons had been discovered but only 3 quarks proposed. The development of their work in 1970, the GIM mechanism showed that the two quark pairs: (d.s), (u,c), would largely cancel out flavor changing neutral currents, which had been observed experimentally at far lower levels than theoretically predicted on the basis of 3 quarks only. The prediction of the charm quark also removed a technical disaster for any quantum field theory with unequal numbers of quarks and leptons — an anomaly — where classical field theory symmetries fail to carry over into the quantum theory.

In 1973, Glashow and Howard Georgi proposed the first grand unified theory. They discovered how to fit the gauge forces in the standard model into an SU(5) group, and the quarks and leptons into two simple representations. Their theory qualitatively predicted the general pattern of coupling constant running, with plausible assumptions, it gave rough mass ratio values between third generation leptons and quarks, and it was the first indication that the law of Baryon number is inexact, that the proton is unstable. This work was the foundation for all future unifying work.

Glashow shared the 1977 J. Robert Oppenheimer Memorial Prize with Feza Gürsey.[4][5]

Superstring theory

Glashow is a skeptic of Superstring theory due to its lack of experimentally testable predictions. He had campaigned to keep string theorists out of the Harvard physics department, though the campaign failed.[6] About ten minutes into "String's the Thing", the second episode of The Elegant Universe TV series, he describes superstring theory as a discipline distinct from physics, saying "...you may call it a tumor, if you will...".[7]

Professor Glashow's KHC PY 101 Energy class, at Boston University's Kilachand Honors College (Spring 2011)

Personal life

Glashow is married to the former Joan Shirley Alexander. They have four children.[2] Lynn Margulis was Joan's sister, making Carl Sagan his former brother-in-law. Daniel Kleitman, who was also a doctoral student of Julian Schwinger, is his brother-in-law, through Joan's other sister, Sharon.

In 2003 he was one of 22 Nobel Laureates who signed the Humanist Manifesto.[8]

Works

See also

References

Notes

  1. ↑ Sheldon Lee Glashow – Britannica Encyclopedia. Britannica.com. Retrieved on 2012-07-27.
  2. 1 2 3 Glashow's autobiography. Nobelprize.org. Retrieved on 2012-07-27.
  3. ↑ Sheldon Glashow. Jewishvirtuallibrary.org. Retrieved on 2012-07-27.
  4. ↑ Walter, Claire (1982). Winners, the blue ribbon encyclopedia of awards. Facts on File Inc. p. 438. ISBN 9780871963864.
  5. ↑ "Gürsey and Glashow share Oppenheimer memorial". Physics Today. American Institute of Physics. May 1977. doi:10.1063/1.3037556. Retrieved 1 March 2015.
  6. ↑ Jim Holt (2006-10-02), "Unstrung", The New Yorker. Retrieved on 2012-07-27.
  7. ↑ "[T]here ain't no experiment that could be done nor is there any observation that could be made that would say, `You guys are wrong.' The theory is safe, permanently safe." He also said, "Is this a theory of Physics or Philosophy? I ask you" NOVA interview
  8. ↑ "Notable Signers". Humanism and Its Aspirations. American Humanist Association. Retrieved October 2, 2012.
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