Rivals

At the Vancouver Winter Olympics, Yu-na Kim of South Korea took the gold medal of women's figure skating competition with a world record score; and Mao Asada of Japan, the silver. Both of them played beautifully and are only 19 years old. Further, they have been rivals each other since quite young days. Thus, their rivalry will perhaps continue through coming years. This reminds me of the relationship between Hideki Yukawa and Shi'nichiro Tomonaga.

Before his publishing of the paper on the meson theory, Yukawa had the days of slowdown in his research at the Department of Physics, Osaka University. Then Hidetsugu Yagi, the then Head of the Department and known by Yagi antenna, said to him, "We had the plan of recruiting Tomonaga but your brother's request compelled us to adopt you. Therefore, we should be in trouble if you do not work harder than Tomonaga." These words stimulated Yukawa soon to complete the research on the prediction of the existence of the meson (this story has been translated and adapted from [1]). He got Nobel Prize in Physics for that work in 1949. Tomonaga shared the same award in 1965 with Julian Schwinger and Richard Feynman for their work in quantum electrodynamics.

I also had some rivals in studying during my schoolboy days. They were mostly girls. Among them, one has been the enduring rival, though our specialties have been quite different. She studied Japanese literature in Edo period and is now Professor Emeritus of the University of California, Santa Barbara, while I am a little proud of publications in many different academic journals ranging from physics to psychology. I rarely meet her or exchange messages with her but am grateful to her for continued rivalry.

(Noticing of [1] owes to the discussion we have had at Osaka Science Museum among the members of "Citizens' Study Group on Hideki Yukawa.")

Note added later: Mao Asada beat Kim Yu-na to win her second title at the World Figure Skating Championships held in Turin, Italy, on March 27, 2010.

1. R. Utiyama's writing, quoted in: "Light" into after-war darkness, Asahi Shimbun, special pages for its 120th anniversary (February 13, 1999) in Japanese.

The Poetic Answer in the Science Test

On February 20, the column of the Asahi Shimbun, "Tensei jingo," treated the nearing of spring. The column began by the question, "What does ice become when it melts?" This was a question in a science test at a primary school in Japan. The teacher expected the answer, "water." However, the question written in Japanese was rather vague, because it was close to this: What does it become when ice melts? Thus, there was a story that a child wrote the answer, "spring." The author of the column wrote this story once before, without being sure of its veracity.

However, the author received a letter from a lady reader, who had been in Supporo, a snowy large city in Hokkaido, as a child. The letter included a multicolor photocopy of a science test. In fact, it was of sepia color, showing the oldness of the test paper. One of the test question was "What does it become when snow melts?" The answer written in pencil was "The ground appears and it becomes spring." The teacher did not consider the answer as correct, and her overall test score was 85 out of 100. The reader wrote that her late mother had held on the paper and that she found it among the belongings left by the latter.

The author concluded the article by the words, 'Yesterday (February 19) it was "rain water" of 24 solar terms in East Asian lunisolar calendars. It signals the beginning of the spring thaw. After just a little of patient waiting, spring is coming again in order to make the child's "wrong answer" right.'

If I were a science teacher who asked the aforementioned question, I would have regarded the poetic answer of "spring" correct. Following the conventional wisdom only, we cannot make scientific discoveries. For fostering scientific mind, teachers should put much importance on children's original answers.

Note: Usually the English version "Vox Populi, Vox Dei" of the "Tensei jingo" column appears online soon after the publication of the Japanese version. However, the English version of the article here mentioned appeared nine days later (March 1) with the title "Hidden buds stir, eager for spring thawing." Thus, I prepared the story included in it by my own translation from the Japanese version, borrowing some expressions from the official English translation after finding it but retaining the others as prepared. The explanation of the vagueness of the relevant question, when expressed in Japanese, is mine.

The Mystery of Yukawa's "New Insight"

Please read the revised version instead of this article:
The Mystery of Yukawa's "New Insight" (Revised).

Read in Japanese.
(The Japanese version has not yet been revised.)

The crucial point in the development of Hideki Yukawa's meson theory came to him one night in October 1934. He writes in his autobiography Tabibito [1] as follows:

My new insight was the realization that this distance [the effective range of the nuclear force] and the mass of the new particle that I was seeking are inversely related to each other. Why had I not noticed that before?

This passage contradicts the fact that Yukawa used the above relation already in 1933. Namely, in April that year he made his first oral presentation at a meeting of an academic society. It was entitled "A consideration about the problem of electrons within nuclei," and the meeting was the one held in Sendai by Physico-Mathematical Society of Japan. The abstract of the presentation includes the following sentence [2]:

From the fact that the electron has the rest mass, we consider that the strength of the interaction decreases rapidly as the distance between the neutron and the proton becomes large compared with h/(2πmc).

In the work of the above presentation, Yukawa treated the possibility that the electron might be the mediator of the nuclear force between the neutron and the proton. This hypothesis included difficulties related to the spin and statistics of the electron. Therefore, Yukawa totally abandoned the hypothesis later together with the relation of the distance and the mass of the particle that would mediate the nuclear force [3]. Did this abandonment make it necessary for Yukawa to rediscover the relation? If so, this explains the contradictory remark of his "new insight."

We find another possible explanation of the contradictory description in the process of the making of Yukawa's autobiography. Hisao Sawano of the Asahi Shimbun Company helped the publication by editing Yukawa's manuscript [4]. If Sawano's editing had been to such an extent as to change Yukawa's original version into more dramatic one here and there, the passage that began with "My new insight" might have been Sawano's creation. To eliminate the expression different from the fact, Yukawa, perhaps, regularly checked the changes made by Sawano. However, Yukawa finished writing the last section related to the discovery of the meson theory just a few hours before his trip to Europe [5]. Thus, it is quite possible that Yukawa did not check Sawano's modification of that section.

Both Yukawa and Sawano are now in heaven, and the mystery of the "new insight," i.e., which of the above two explanations was the case, cannot be solved easily.

(This article owes much to the discussion we have had at Osaka Science Museum among the members of "Citizens' Study Group on Hideki Yukawa.")

Read the continuation of this article: The Solution to the Mystery of Yukawa's "New Insight"

1. H. Yukawa, Tabibito (The Traveler), translated by L. Brown and R. Yoshida (World Scientific, 1982) p. 202.
2. H. Yukawa, Sūbutu-gakkaisi, Vol. 7, No. 2 (1933) quoted in Nihon-no Buturigaku-shi (History of Physics in Japan) (Tokai University Press, 1978) p. 319 (in Japanese; English translation of the quoted passage by the present author).
3. M. Kawabe and M. Konuma, Butsuri Vol. 37, p. 265 (1982) (in Japanese).
4. H. Yukawa, Atogaki (Afterwords) in Tabibito, (Kadokawa, 1960) (in Japanese).
5. H. Yukawa, Hon-no Naka-no Sekai (The World in Books) (Iwanami, 1963) p. 182 (in Japanese).

Effects of Chinese Classic Literature on H. Yukawa's Work

The following is the outline of my talk to be delivered at Himeji Kyoyukai meeting on February 18, 2010, in Himeji.

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The Nobel-winning physicist Hideki Yukawa developed the theory of elementary domains for particle physics together with his coworkers in his later years [1, 2]. In the preface of a book [3], he writes that the important factor that led him to the idea of this theory was the words of the Chinese poet Li Po (701­­–762), "Heaven and Earth are hotels for everything, and days and nights are travelers of hundreds of generations." He also writes that scientific research and literature are not separate things for him.

Yukawa also writes in a textbook on particle physics [4] that Li Po's words mentioned above was one of the motivations that brought his unconscious idea about the elementary domains to his consciousness. While being rather lengthy for introducing the concept of the elementary domains in a textbook, the paragraphs including the above words are considered the valuable record of Yukawa's processes of thinking.

In his lecture on experimental nuclear physics, Kiichi Kimura, a classmate of Yukawa's at Kyoto University, told us that some words in the Taoist book Zhuangzi might have been a hint on Yukawa's meson theory that brought him the Nobel Prize. I do not remember the words Kimura quoted from Zhuangzi. In his 1961 essay [5] on Zhuangzi, however, Yukawa writes that he had read Taoist books Zhuangzi and Laozi in his middle school days, but was forgetting philosophical thoughts in them for many years after that. This means: When he was thinking about meson theory, Yukawa was forgetting Zhuangzi. Thus, the words of Zhuangzi Kimura mentioned had not been a direct hint, at least, on the idea of the meson.

It was reported [6] that the meson theory had been motivated by the occasion of the childbirth of Yukawa's wife. Namely, the judo expert Sachio Ashida remembered to have been told in a commuting tramcar by Yukawa, "A baby can exert an attractive force between the parents. There may be a similar existence in the nucleus." I suppose that this was Yukawa's jocular explanation of his idea for the layperson. Yukawa should have gotten the idea of the meson from the study of earlier papers by Werner Heisenberg and Enrico Fermi together with the analogy of the electromagnetic field mediated by the photon. Note here that he used a good analogy.

In his essay mentioned above [5], Yukawa writes that he reminded himself of an allegory in Zhuangzi when he was thinking about something at a deeper level than "elementary particles," which amounted to more than 30 kinds those days. The allegory was about the king who lacked all the seven holes in the face, i.e., ears, eyes, nostrils and a mouth, and was named Chaos ("Konton" in Japanese). The underdeveloped state of the king was appropriate for Yukawa to express his idea of something at a deeper level.

Yukawa also liked the following words from Zhuangzi: "On the basis of the beauty of Heaven and Earth, we arrive at the reason of everything." He made these words in Chinese characters use as a watermark of the invitation letter for "International Meeting on Elementary Particles: The Thirtieth Anniversary of the Meson Theory" [7].

To develop a new theory in the field of particle physics, it is necessary to have good mathematical skill of formulating equations to express a physical model, as well as strong imaginative power to think of a new model. One of the important device with which Yukawa cultivated the latter ability should have been Chinese classic literature, which includes a lot of allegories and helps one to develop thinking by the use of an analogy. Thus his reading of Chinese classic literatures in his young days was useful not only directly for the idea of elementary domains, but, quite possibly, also indirectly for the idea of the meson.

(This article owes much to the discussion we have had at Osaka Science Museum among the members of "Citizens' Study Group on Hideki Yukawa.")

References

1. Y. Katayama and H. Yukawa, "Field Theory of Elementary Domains and Particles. I" Progress of Theoretical Physics Supplement No. 41, p. 1 (1968).
2. Y. Katayama, I. Umemura and H. Yukawa, "Field Theory of Elementary Domains and Particles. II" ibid. p. 22 (1968).
3. H. Yukawa, Auto-selection of Hideki Yukawa's Essays Vol. 5 (Asahi-shimbun, Tokyo, 1971) [in Japanese].
4. H. Yukawa, Unified Theories of Particles, in Iwanami Lectures: Foundations of Modern Physics, Vol. 11, H. Yukawa and Y. Katayama, ed., p. 563 (Iwanami, Tokyo, 1974) [in Japanese].
5. H. Yukawa, Zhuangzi, in Auto-selection of Hideki Yukawa's Essays Vol. 3, p. 363 (Asahi-shimbun, Tokyo, 1971) [in Japanese].
6. Personal connections in Japan: The spirit of Judo (8), Asahi-shimbun, Evening issue (May 25, 2006) [in Japanese].
7. The 30th anniversary of Meson theory (1), Asahi-shimbun (September 20, 1965) [in Japanese].

Hideki Matsui Won MVP

The New York Yankees won the 27th World Series title on Wednesday, November 4, 2009. The designated hitter Hideki Matsui (35 years old), drove in six of the Yankee's seven runs in their series-winning victory. He hit .615 with three home runs and eight RBIs in the series, and became the first Japanese-born World Series Most Valuable player. Matui was reported to have said, "Winning the championship is such a great feeling. I guess you can say that this is the best moment of my life right now."

In the summer of 1992, Matsui, as the fourth batter of Seiryo Senior High School team drew five intentional walks in a game at Koshien Stadium. It was the very uncommon strategy of the opposite team not to make him hit home runs and to win cunningly. I watched that game on TV and impressed by Matsui, who did not show any look of embarrassment or angriness and coolly walked to the first base each time. Such a broad mind of Matsui and his continued effort, I believe, has brought him this best moment of his life. I am especially proud of him because I was born in the same prefecture of Ishikawa as he.