Discover
/
Article

The electron dipole moment—A case history

FEB 01, 1966
The anomalous magnetic moment of the electron is of great significance in the study of elementary particles and quantum electrodynamics. The history of its discovery is in large part the story of a technique:—the use of molecular beams—which was not invented for the specific purpose hut which did, by permitting a discrepancy to appear where none was expected, answer an unasked question.
Polykarp Kusch

THE ELECTRON is one of the fundamental particles in the universe and is likely to remain one. It is as abundant as any other particle with the possible exception of the neutrino. There may be more neutrinos around, but I am not expert on that question. The electron has a definite charge and a definite rest mass.

This article is only available in PDF format

References

  1. 1. Reprints of both Thomson’s and Millikan’s papers appear in Great Experiments in Physics. Morris Shamos, Ed. Henry Holt, New York, 1959.

  2. 2. As is true of almost every major event in the history of physics, the proposals of Goudsmit and Uhlenbeck were not made without some previous provocative suggestions. See, for instance, Whittaker, A History of the Theories of Aether and Electricity, Vol. II, pages 133, 134. Harper, New York, 1960.

  3. 3. Kinsler: Phys. Rev. 46, 533 (1934).https://doi.org/PHRVAO

  4. 4. Dunoyer: Compt. rend. 152, 592 (1911); https://doi.org/COREAF
    J. Phys. Radium, 8, 142 (1911).

  5. 5. Stern: Gerlach and Stern: Z. Physik, 7, 249 (1921); https://doi.org/ZEPYAA
    Stern: Gerlach and Stern, 8, 110 (1922); https://doi.org/ZEPYAA , Z. Phys.
    Stern: Gerlach and Stern, 9, 349 (1922).https://doi.org/ZEPYAA , Z. Phys.

  6. 6. The emphasis on the molecular‐beam magnetic‐resonance method as a generalized spectrometric procedure is not made in the early papers. In 1939 Rabi, Millman, Kusch, and Zacharias (Phys. Rev. 55, 526) discussed the trajectories of molecules in a system of inhomogeneous magnetic fields and, very importantly, the process of changing the orientation of a magnetic dipole in a magnetic field.

  7. 7. Taylor: Z. Physik, 57, 242 (1929).https://doi.org/ZEPYAA

  8. 8. Rabi, Zacharias, Millman, Kusch: Phys. Rev. 53, 318 (1938).https://doi.org/PHRVAO

  9. 9. The use of the two‐wire system for producing inhomogeneous magnetic fields with precisely calculable properties was described by Rabi, Kellogg and Zacharias in 1934. The extrapolation of the system to iron magnets in which much higher fields would be produced was described by Millman, Rabi and Zacharias in 1938. (Phys. Rev. 53, 384).

  10. 10. Rabi, Zacharias, Millman, Kusch: Phys. Rev. 53, 318 (1938).https://doi.org/PHRVAO

  11. 11. Millman: Phys. Rev. 55, 628 (1939).https://doi.org/PHRVAO

  12. 12. Kellogg, Rabi, Ramsey: Phys. Rev. 56, 728 (1939).https://doi.org/PHRVAO

  13. 13. Kellogg, Rabi, Ramsey, Zacharias: Phys. Rev. 57, 677 (1940).https://doi.org/PHRVAO

  14. 14. Kusch, Millman, Rabi: Phys. Rev. 57, 765 (1940).https://doi.org/PHRVAO

  15. 15. Zacharias: Phys. Rev. 61, 270 (1942).https://doi.org/PHRVAO

  16. 16. Millman, Kusch: Phys. Rev. 60, 91 (1941).https://doi.org/PHRVAO

  17. 17. Becker, Kusch: Phys. Rev. 73, 584 (1948).https://doi.org/PHRVAO

  18. 18. Hardy, Millman: Phys. Rev. 61, 459 (1942).https://doi.org/PHRVAO

  19. 19. Nafe, Nelson, Rabi: Phys. Rev. 71, 914 (1947); https://doi.org/PHRVAO
    Nafe, Nelson: Phys. Rev. 75, 1194 (1949).https://doi.org/PHRVAO

  20. 20. Breit: Phys. Rev. 72, 984 (1947).https://doi.org/PHRVAO

  21. 21. Kusch, Foley: Phys. Rev. 72, 1256 (1947).https://doi.org/PHRVAO

  22. 22. Foley, Kusch: Phys. Rev. 73, 412 (1948).https://doi.org/PHRVAO

  23. 23. Kusch, Foley: Phys. Rev. 74, 250 (1948).https://doi.org/PHRVAO

  24. 24. Schwinger: Phys. Rev. 73, 416 (1948).https://doi.org/PHRVAO

  25. 25. Schwinger: Phys. Rev. 73, 416 (1948).https://doi.org/PHRVAO

  26. 26. Taub, Kusch: Phys. Rev. 75, 1481 (1949).https://doi.org/PHRVAO

  27. 27. Kusch, Taub: Phys. Rev. 75, 1477 (1949).https://doi.org/PHRVAO

  28. 28. Gardner, Purcell: Phys. Rev. 76, 1262 (1949); https://doi.org/PHRVAO
    Gardner, Purcell, 83, 996 (1951).https://doi.org/PHRVAO , Phys. Rev.

  29. 29. Karplus, Kroll: Phys. Rev. 77, 536 (1950).https://doi.org/PHRVAO

  30. 30. Koenig, Prodell, Kusch: Phys. Rev. 88, 191 (1952).https://doi.org/PHRVAO

  31. 31. Franken, Liebes: Phys. Rev. 104, 1197 (1956); https://doi.org/PHRVAO
    Franken, Liebes, 116, 633 (1959).https://doi.org/PHRVAO , Phys. Rev.

  32. 32. Sommerfield: Phys. Rev. 107, 328 (1957).https://doi.org/PHRVAO

  33. 33. Beringer, Heald: Phys. Rev. 95, 1474 (1954).https://doi.org/PHRVAO

  34. 34. Wilkinson, Crane: Phys. Rev. 130, 852 (1963).https://doi.org/PHRVAO

More about the authors

Polykarp Kusch, Columbia University.

Related content
/
Article
Figuring out how to communicate with the public can be overwhelming. Here’s some advice for getting started.
/
Article
Amid growing investment in planetary-scale climate intervention strategies that alter sunlight reflection, global communities deserve inclusive and accountable oversight of research.
/
Article
Although motivated by the fundamental exploration of the weirdness of the quantum world, the prizewinning experiments have led to a promising branch of quantum computing technology.
/
Article
As conventional lithium-ion battery technology approaches its theoretical limits, researchers are studying alternative architectures with solid electrolytes.
This Content Appeared In
pt-cover_1966_02.jpeg

Volume 19, Number 2

Get PT in your inbox

pt_newsletter_card_blue.png
PT The Week in Physics

A collection of PT's content from the previous week delivered every Monday.

pt_newsletter_card_darkblue.png
PT New Issue Alert

Be notified about the new issue with links to highlights and the full TOC.

pt_newsletter_card_pink.png
PT Webinars & White Papers

The latest webinars, white papers and other informational resources.

By signing up you agree to allow AIP to send you email newsletters. You further agree to our privacy policy and terms of service.