On Kamefuchi's Essay about Heisenberg and Yukawa (4)

Reference [12] of this article.

2 Heisenberg's tragedy (continued)

2.6 Impact of Heisenberg's research at that time

About the research of Heisenberg and Yukawa at the time of the event mentioned in the essay, Kamefuchi wrote, "Unfortunately, both the studies were unfinished." I'll write later about what he wrote as a common reason for the incompleteness of them. Even though Heisenberg's research at that time was incomplete in itself, the concepts used in it seems to have had a considerable positive effect on other researchers. Concerning this, I would like to quote the description by Professor Cao of Boston University, who specializes in the history of science.

　At the 1958 Rochester Conference on high-energy nuclear physics held in Geneva, Heisenberg invoked the idea of a degenerate vacuum to account for internal quantum numbers, such as isospin and strangeness, that provide selection rules for elementary particle interactions (1958).*
　In an influential paper submitted in 1959,** Heisenberg and his collaborators used his concept of a degenerate vacuum in QFT [quantum field theory] to explain the breaking of isospin symmetry by electromagnetism and weak interactions. [...]
　Heisenberg's degenerate vacuum was at the time widely discussed at international conferences. It was frequently quoted, greatly influenced field theorists, and helped to clear the way for the extension of SSB [spontaneous symmetry breaking] from hydrodynamics and condensed matter theory to QFT. ([12] p. 283)

The word "degenerate vacuum" that appears many times in the above quote is closely related to the SSB (spontaneous symmetry breaking) in the last sentence. The reference cited at the place of the symbol * is the reference [2] in Part 1 of the present article, and the paper cited at ** is the reference [8] in Part 2. The former is the lecture of "Tragedy" published in the proceedings, and the latter is the paper published later in collaboration with young researchers.

By the way, if you look up the number of citations of these papers on Google Scholar, it is 16 for the former and 226 for the latter. Cao uses the words "frequently quoted" for Heisenberg's work at the time. However, the above citation numbers are much smaller than those of Heisenberg's famous papers. Namely, the citation number for the Nobel Prize-winning paper on the formulation of quantum mechanics based on matrices [13] is 1709, and that for the work on the uncertainty principle [14] is 4697. (All the citation numbers are as of July 27, 2020.) The reason for the small citation numbers for the research during the period of "tragedy" seems that it did not succeed as the whole concept.

Speaking of the application of SSB to particle physics, I remember that the reason for receiving the Nobel Prize by Yoichiro Nambu was "discovery of the mechanism of SSB in particle physics." So, I have thought that it was almost Nambu's originality. However, in fact, Heisenberg's research had an impact on Nambu. About this, I make here a bit long quote from Cao's book (numbers representing Nambu's papers cited are omitted).

　Nambu's work on superconductivity led him to consider the possible application to particle physics of the idea of non-invariant solutions (especially in the vacuum state). [...]
　[...]
　[...]
　It is of interest to note the impact of Dirac and Heisenberg on Nambu's pursuing this analogy. First, Nambu took Dirac's idea of holes very seriously and viewed the vacuum not as a void but as a plenum packed with many virtual degrees of freedom. This plenum view of the vacuum made it possible for Nambu to accept Heisenberg's concept of degeneracy of the vacuum, which lay at the heart of SSB. Second, Nambu was trying to construct a composite particle model and chose Heisenberg's non-linear model, 'because the mathematical aspect of symmetry breaking could be mostly demonstrated there', although he never liked the theory or took it seriously.

Next time, I would like to write about a paper related to "tragedy" in the case of Yukawa.

References

12. T. Y. Cao, Conceptual Developments of 20th Century Field Theories, (Cambridge University Press, Cambridge, 1997; second edition available, 2019).
13. W. Heisenberg, Über quantentheoretische Umdeutung kinematischer und mechanischer Beziehungen, Z. Physik 33, 879 (1925).
14. W. Heisenberg, Über den anschaulichen Inhalt der quantentheoretischen Kinematik und Mechanik, Z. Physik 43, 172 (1927).

(To be continued)
Last modified Jan 22, 2021.
Search word: Kamefuchi-2020