Julian Schwinger

Renormalization and the electron's extra magnetism (1947-1949)

• QED, which he helped put on a sound footing, has been tested against the electron's magnetism to about one part in a trillion; his 1947 formula alone lands within about 0.15 percent of the measured value.^[3],[7],[16]
• From late 1943 he was the leading theorist at the MIT Radiation Laboratory, which developed more than 100 radar systems, including ones that helped defeat the U-boats and the V-1 flying bombs.^[5],[6],[13]
• By 1945 he had worked out the detailed classical theory of light from electrons in circular accelerators; Langmuir called the glow 'Schwinger radiation'. By 2017 about 90% of X-ray protein structures came from synchrotron beamlines.^[14],[15]
• About 70 students earned PhDs under him. Four became Nobel laureates, as did Walter Gilbert, who spent a year as his assistant, and nine of his students were elected to the National Academy of Sciences.^{[5],[10],[11]}
• In 1957 he predicted a second kind of neutrino, after proposing heavy charged particles to carry the weak force. His student Sheldon Glashow calls him the first to use gauge theories to unite the weak and electromagnetic forces.^{[2],[6],[9],[10]}
• In 2022 a University of Manchester team led by Andre Geim used graphene to mimic the 'Schwinger effect', named for his 1951 calculation of how very strong electric fields can pull particle pairs out of empty space.^[17],[20]

We record no numbers for Schwinger. His Nobel work was theory, and his most practical contributions, to wartime radar and to the physics of synchrotron light, were steps within vast team efforts: the Radiation Laboratory employed 3,500 people at its peak, and today's light sources rest on decades of accelerator engineering by others. Any count of lives saved or dollars earned credited to him would be guesswork. What can be said plainly is where his work lives on: in precision tests of QED, in the theory of the light that synchrotrons use to reveal the shapes of proteins, in methods used to study electronic devices and the early universe, and in the physicists he trained, four of whom won Nobel Prizes. We record no harm figure either. He spent a summer in 1943 at the bomb project in Chicago but chose not to continue, and we found no record of a specific contribution by him to the bombs dropped on Hiroshima and Nagasaki.

Fundamental scienceTechnologyEducation

No number is given here on purpose. Some contributions cannot be counted honestly, and we would rather describe them than invent a figure.

• Minor

  A summer at the bomb project

  Invited by Oppenheimer, Schwinger spent the summer of 1943 at the Metallurgical Laboratory in Chicago, part of the Manhattan Project; the Atomic Heritage Foundation says he briefly worked on the bomb there. He decided he did not want to help develop it and left for radar work in the fall. We found no record of a specific contribution by him to the weapons used on Hiroshima and Nagasaki.^[5],[8],[21]

• Minor

  Theory behind military radar

  From 1943 to 1945 Schwinger was the leading theorist at the MIT Radiation Laboratory. Its radars defended ships, convoys and cities, but they also included airborne bombing radars and radars that aimed guns. His contribution was general theory of microwave circuits used across the laboratory rather than the design of any one weapon.^[6],[7],[13]

• Minor

  Support for cold fusion

  After chemists announced 'cold fusion' in 1989, Schwinger argued that the effect might be real. Physical Review Letters rejected his paper, and he resigned from the American Physical Society in protest. By the early 1990s cold fusion was largely discredited; his former student and biographer Kimball Milton writes that the episode soon looked like a characteristic case of 'pathological science'.^[5],[6]

• —

  Other

  The Great Depression cost his father his clothing-design business. The family got by, less comfortably than before, and Julian had to rely on free public schooling and a free city college.^[6]

• 1934

  Quota

  He entered the free City College of New York in 1934, in an era when elite private colleges limited Jewish admissions. Columbia had cut its Jewish share from 40 to 22 percent in 1920-22; City College was already 80 to 90 percent Jewish by 1920.^[5],[7],[12]

• —

  Discrimination

  At City College the head of the mathematics department, described by Schwinger's biographer Kimball Milton as apparently a notorious antisemite, discouraged Jewish students from studying mathematics.^[6]

• 1941

  Discrimination

  Although he had already published important papers and lectured at the Michigan summer school alongside Wolfgang Pauli, no leading university competed to hire him in 1941. His National Academy memoir says a long tradition of antisemitism may have been a factor. He accepted a junior instructorship at Purdue.^[2],[5],[6]

Both parents were Jewish immigrants from Eastern Europe. His mother, Belle Rosenfeld, was born in Lodz, then in the Russian-ruled part of Poland, and came to America as a small child. His father, Benjamin Schwinger, came from a village in the Carpathian foothills of Austria-Hungary and became a successful designer of women's clothing. The couple first lived in Harlem, then a well-to-do Jewish neighborhood. The biographies we read say almost nothing about his adult relationship to Judaism, and we found no public statements by him about Jewish identity.^[7],[9]

1. February 12, 1918

   Born in upper Manhattan, New York City, the second son of Jewish immigrants Belle Rosenfeld and Benjamin Schwinger, a designer of women's clothing.^[1],[5],[7]

2. 1934

   Enters the free City College of New York; in 1935 he publishes his first physics paper, written with Otto Halpern.^[5],[7]

3. July 10, 1935

   Hans Bethe writes to I. I. Rabi that the 17-year-old will develop into one of the world's foremost theoretical physicists if properly guided.^[5]

4. 1936

   With Rabi's help, transfers to Columbia University, where he completes his bachelor's degree.^[5],[6],[7]

5. 1939

   Receives his PhD from Columbia under Rabi, then spends two years at Berkeley, first as a National Research Fellow and then as J. Robert Oppenheimer's assistant.^[2],[5],[7]

6. 1941

   Takes a junior post as a physics instructor at Purdue University after no leading university competes to hire him.^[5],[7]

7. 1943

   Spends the summer at the bomb project's laboratory in Chicago, decides not to take part, and joins MIT's Radiation Laboratory to work on radar.^[5],[8],[21]

8. 1945

   Accepts an appointment as associate professor at Harvard, where he begins teaching in 1946.^[2],[6],[7]

9. June 1947

   Days after the Shelter Island conference, where new measurements exposed flaws in the theory of the electron, he marries Clarice Carrol of Boston.^[2],[5],[6]

10. December 1947

    Calculates the electron's extra magnetism, α/2π, using renormalization; Harvard makes him a full professor the same year.^[2],[6],[7]

11. January 1948

    Presents his results to overflow audiences at a physics meeting at Columbia; his three-part reformulation of QED follows in 1948-49.^[5],[6]

12. 1965

    Shares the Nobel Prize in Physics with Sin-Itiro Tomonaga and Richard Feynman for their fundamental work in quantum electrodynamics.^[1],[3]

13. 1971

    Leaves Harvard for the University of California, Los Angeles, where he stays for the rest of his career.^[5],[6],[7]

14. July 16, 1994

    Dies of pancreatic cancer in Los Angeles at 76; he is buried at Mount Auburn Cemetery in Cambridge, Massachusetts, under a stone engraved α/2π.^{[1],[5],[7],[18],[19]}

1. 1.Julian Schwinger - Facts · NobelPrize.org (Nobel Prize Outreach)
2. 2.Julian Schwinger - Biographical · NobelPrize.org (from Nobel Lectures, Physics 1963-1970, Elsevier, 1972), 1972
3. 3.The Nobel Prize in Physics 1965 - Award ceremony speech by Ivar Waller · NobelPrize.org, 1965
4. 4.Julian Schwinger - Nobel Lecture: Relativistic Quantum Field Theory (11 December 1965) · NobelPrize.org, 1965
5. 5.Julian Schwinger 1918-1994: A Biographical Memoir, by Paul C. Martin and Sheldon L. Glashow · National Academy of Sciences, 2008
6. 6.Julian Schwinger: Nuclear Physics, the Radiation Laboratory, Renormalized QED, Source Theory, and Beyond, by Kimball A. Milton (Physics in Perspective 9: 70-114) · arXiv (Cornell University), 2007
7. 7.Schwinger, Julian Seymour, by Silvan S. Schweber (Complete Dictionary of Scientific Biography) · Encyclopedia.com (Charles Scribner's Sons / Gale), 2008
8. 8.The Greening of Quantum Field Theory: George and I, by Julian Schwinger (lecture at Nottingham, 14 July 1993) · arXiv (Cornell University), 1993
9. 9.Julian Schwinger: A Centennial Celebration at Harvard, by Steve Nadis · arXiv (Cornell University), 2018
10. 10.Remembering Towering Physicist Julian Schwinger (1918-1994), by Jonathan Shaw · Harvard Magazine, 2018
11. 11.Julian Schwinger (short biography) · Julian Schwinger Foundation
12. 12.How Jewish Quotas Began, by Stephen Steinberg · Commentary, 1971
13. 13.MIT Radiation Laboratory (laboratory history) · MIT Lincoln Laboratory
14. 14.X-Ray Data Booklet, Section 2.2: History of Synchrotron Radiation, by Arthur L. Robinson · Lawrence Berkeley National Laboratory
15. 15.New developments in crystallography: exploring its technology, methods and scope in the molecular biosciences, by John R. Helliwell (Bioscience Reports 37: BSR20170204) · Portland Press, via PubMed Central, 2017
16. 16.Measurement of the Electron Magnetic Moment, by X. Fan, T. G. Myers, B. A. D. Sukra and G. Gabrielse (Physical Review Letters 130, 071801) · arXiv (Cornell University), 2023
17. 17.Cosmic physics mimicked on table-top as graphene enables Schwinger effect · The University of Manchester, 2022
18. 18.Julian Schwinger · Wikipedia
19. 19.File:Julian Schwinger headstone.JPG (photograph of his headstone at Mount Auburn Cemetery, Cambridge, MA, by Jacob Bourjaily) · Wikimedia Commons, 2013
20. 20.Julian Seymour Schwinger, by J J O'Connor and E F Robertson · MacTutor History of Mathematics, University of St Andrews
21. 21.Julian Schwinger · Atomic Heritage Foundation, National Museum of Nuclear Science & History