Hideki Yukawa

Hideki Yukawa ForMemRS[1] FRSE (湯川 秀樹 Yukawa Hideki, 23 January 1907 – 8 September 1981), was a Japanese theoretical physicist and the first Japanese Nobel laureate for his prediction of the pi meson.

Hideki Yukawa
Yukawa in 1951
Native name
湯川 秀樹
Born23 January 1907
Died8 September 1981 (aged 74)
Nationality Japanese
Alma materKyoto Imperial University, Osaka Imperial University
Spouse(s)Sumi Yukawa
Scientific career
FieldsTheoretical physics
InstitutionsOsaka Imperial University
Kyoto Imperial University
Imperial University of Tokyo
Institute for Advanced Study
Columbia University
Academic advisorsKajuro Tamaki
Doctoral studentsMendel Sachs
InfluencesEnrico Fermi
Hideki Yukawa signature


He was born as Hideki Ogawa in Tokyo and grew up in Kyoto with two older brothers, two older sisters, and two younger brothers.[2] He read the Confucian Doctrine of the Mean, and later Lao-Tzu and Chuang-Tzu. His father, for a time, considered sending him to technical college rather than university since he was "not as outstanding a student as his older brothers". However, when his father broached the idea with his middle school principal, the principal praised his "high potential" in mathematics and offered to adopt Ogawa himself in order to keep him on a scholarly career. At that, his father relented.

Ogawa decided against becoming a mathematician when in high school; his teacher marked his exam answer as incorrect when Ogawa proved a theorem but in a different manner than the teacher expected.[2] He decided against a career in experimental physics in college when he demonstrated clumsiness in glassblowing, a requirement for experiments in spectroscopy.[2]

In 1929, after receiving his degree from Kyoto Imperial University, he stayed on as a lecturer for four years. After graduation, he was interested in theoretical physics, particularly in the theory of elementary particles. In 1932, he married Sumi Yukawa (スミ). In accordance with Japanese customs of the time, since he came from a family with many sons but his father-in-law Genyo had none, he was adopted by Genyo and changed his family name from Ogawa to Yukawa.[2] The couple had two sons, Harumi and Takaaki. In 1933 he became an assistant professor at Osaka University, at 26 years old.

In 1935 he published his theory of mesons, which explained the interaction between protons and neutrons, and was a major influence on research into elementary particles.[3] In 1940 he became a professor in Kyoto University. In 1940 he won the Imperial Prize of the Japan Academy, in 1943 the Decoration of Cultural Merit from the Japanese government. In 1949 he became a professor at Columbia University, the same year he received the Nobel Prize in Physics, after the discovery by Cecil Frank Powell, Giuseppe Occhialini and César Lattes of Yukawa's predicted pi meson in 1947. Yukawa also worked on the theory of K-capture, in which a low energy electron is absorbed by the nucleus, after its initial prediction by G. C. Wick.[4]

Yukawa became the first chairman of Yukawa Institute for Theoretical Physics in 1953. He received a Doctorate, honoris causa, from the University of Paris and honorary memberships in the Royal Society,[1] Royal Society of Edinburgh, the Indian Academy of Sciences, the International Academy of Philosophy and Sciences, and the Pontificia Academia Scientiarum.

He was an editor of Progress of Theoretical Physics,[5] and published the books Introduction to Quantum Mechanics (1946) and Introduction to the Theory of Elementary Particles (1948).

In 1955, he joined ten other leading scientists and intellectuals in signing the Russell–Einstein Manifesto, calling for nuclear disarmament.

Yukawa retired from Kyoto University in 1970 as a Professor Emeritus. Owing to increasing infirmity, in his final years he appeared in public in a wheelchair. He died at his home in Sakyo-ku, Kyoto, on 8 September 1981 from pneumonia and heart failure, aged 74. His tomb is in Higashiyama-ku, Kyoto.

Solo violinist Diana Yukawa (ダイアナ湯川) is a relative of Hideki Yukawa.


Hideki Yukawa with family 1949
Yukawa with family in 1949


  • Profiles of Japanese science and scientists, 1970 – supervisory editor: Hideki Yukawa (1970)
  • Creativity and intuition: a physicist looks at East and West by Hideki Yukawa; translated by John Bester (1973)
  • Scientific works (1979)
  • Tabibito (旅人) – The Traveler by Hideki Yukawa; translated by L. Brown & R. Yoshida (1982), ISBN 9971950103

See also


  1. ^ a b c d Kemmer, N. (1983). "Hideki Yukawa. 23 January 1907-8 September 1981". Biographical Memoirs of Fellows of the Royal Society. 29: 660–676. doi:10.1098/rsbm.1983.0023. JSTOR 769816.
  2. ^ a b c d Yukawa, Hideki (1982). Tabibito (旅人) = The Traveler. World Scientific. pp. 46–47 & 118, 121–123, 10, Foreword, 141 & 163. ISBN 9971950103. Retrieved 14 August 2016.
  3. ^ Yukawa, H. (1935). "On the Interaction of Elementary Particles" (PDF). Proc. Phys.-Math. Soc. Jpn. 17 (48).
  4. ^ Segré, Emilio (1987) "K-Electron Capture by Nuclei", pp. 11–12, chapter 3 in Discovering Alvarez: selected works of Luis W. Alvarez, with commentary by his students and colleagues, Luis W. Alvarez and W. Peter Trower, University of Chicago Press. ISBN 0-226-81304-5.
  5. ^ Yukawa Institute for Theoretical Physics; Gakkai, Nihon Butsuri (1946). Progress of Theoretical Physics. Kyoto: Yukawa Institute for Theoretical Physics and Physical Society of Japan. OCLC 44519062. Archived from the original on 3 February 2002. Retrieved 3 March 2008.

External links

1907 in Japan

Events in the year 1907 in Japan.

1949 in Japan

Events in the year 1949 in Japan.

1981 in Japan

Events in the year 1981 in Japan.

Academic genealogy of theoretical physicists

The following is an academic genealogy of theoretical physicists and is constructed by following the pedigree of thesis advisors. If an advisor did not exist, or if the field of physics is unrelated, an academic genealogical link can be constructed by using the university from which the theoretical physicist graduated.

An academic genealogy tree lists the physicists' PhD (or in some cases BA/MA) date and school, if known. Nobel Prize winners are indicated by †. If physicists are advised by mathematicians, their genealogy can be readily traced using the Mathematics Genealogy Project.

For the meaning of "s.v.", see here.

Born reciprocity
Not to be confused with the Born rule, which relates to the probability of the outcome of a measurement on a quantum system.

In physics, Born reciprocity, also called reciprocal relativity or Born–Green reciprocity, is a principle set up by theoretical physicist Max Born that calls for a duality-symmetry among space and momentum. Born and his co-workers expanded his principle to a framework that is also known as reciprocity theory.

Born noticed a symmetry among configuration space and momentum space representations of a free particle, in that its wave function description is invariant to a change of variables x → p and p → −x. (It can also be worded such as to include scale factors, e.g. invariance to x → ap and p → −bx where a, b are constants.) Born hypothesized that such symmetry should apply to the four-vectors of special relativity, that is, to the four-vector space coordinates

and the four-vector momentum (four-momentum) coordinates

Both in classical and in quantum mechanics, the Born reciprocity conjecture postulates that the transformation x → p and p → −x leaves invariant the Hamilton equations:


From his reciprocity approach, Max Born conjectured the invariance of a space-time-momentum-energy line element. Born and H.S. Green similarly introduced the notion an invariant (quantum) metric operator as extension of the Minkowski metric of special relativity to an invariant metric on phase space coordinates. The metric is invariant under the group of quaplectic transformations.

Such a reciprocity as called for by Born can be observed in much, but not all, of the formalism of classical and quantum physics. Born's reciprocity theory was not developed much further for reason of difficulties in the mathematical foundations of the theory.

However Born's idea of a quantum metric operator was later taken up by Hideki Yukawa when developing his nonlocal quantum theory in the 1950s. In 1981, Eduardo R. Caianiello proposed a "maximal acceleration", similarly as there is a minimal length at Planck scale, and this concept of maximal acceleration has been expanded upon by others. It has also been suggested that Born reciprocity may be the underlying physical reason for the T-duality symmetry in string theory, and that Born reciprocity may be of relevance to developing a quantum geometry.

Born chose the term "reciprocity" for the reason that in a crystal lattice, the motion of a particle can be described in p-space by means of the reciprocal lattice.

Chushiro Hayashi

Chushiro Hayashi (林 忠四郎, Hayashi Chūshirō, July 25, 1920 – February 28, 2010) was a Japanese astrophysicist. Hayashi tracks on the Hertzsprung–Russell diagram are named after him.

Hayashi was born in Kyoto and enrolled at the Imperial University of Tokyo in 1940, earning his BSc in Physics after 2½ years, in 1942. He was conscripted into the navy and, after the war ended, joined the group of Hideki Yukawa at Kyoto University. He was appointed a professor at Kyoto University in 1957.He made additions to the big bang nucleosynthesis model that built upon the work of the classic Alpher–Bethe–Gamow paper.

Probably his most famous work was the astrophysical calculations that led to the Hayashi tracks of star formation, and the Hayashi limit that puts a limit on star radius.

He was also involved in the early study of brown dwarfs, some of the smallest stars formed.He retired in 1984 and died from pneumonia at a Kyoto hospital on February 28, 2010.

Huzihiro Araki

Huzihiro Araki (荒木 不二洋, Araki Fujihiro, born 28 July 1932) is a Japanese mathematical physicist and mathematician.

Araki is the son of the University of Kyoto physics professor Gentarō Araki, with whom he studied and with whom in 1954 he published his first physics paper. He earned his diploma under Hideki Yukawa and in 1960 he attained his doctorate at Princeton University with thesis advisors Rudolf Haag and Arthur Strong Wightman (Hamiltonian formalism and canonical commutation relations in quantum field theory). He was since 1966 professor at the University of Kyoto, at the Research Institute for Mathematical Sciences (RIMS), of which he was also the director.

Araki works on axiomatic quantum field theory and statistical mechanics in particular on application of operator algebras (von Neumann algebras, C*-algebras). He already at the beginning of the 1960s at Princeton made important contributions to the "local quantum physics" of Haag and Kastler and also to the scattering theories of Haag and David Ruelle. He also supplied important contributions in the mathematical theory of operator algebras, classifying type-III factors of von Neumann algebras. Araki originated the concept of relative entropy of states of Von Neumann algebras. In the 1970s he showed the equivalence in quantum thermodynamics of, on the one hand, the KMS (Kubo-Martin-Schwinger) condition for the characterization of quantum mechanical states in thermodynamic equilibrium with, on the other hand, the variational principle for quantum mechanical spin systems on lattices. With Yanase he worked on the foundations of quantum mechanics (Wigner-Araki-Yanase Theorem, which describes restrictions that conservation laws impose upon the physical measuring process). Stated in more precise terms, they proved that an exact measurement of an operator, which additively replaces the operator with a conserved size, is impossible. However, Yanase did prove that the uncertainty of the measurement can be made arbitrarily small, provided that the measuring apparatus is sufficiently large.He was the first president of the International Association of Mathematical Physics. In 2003 he received with Oded Schramm and Elliott Lieb the Henri Poincaré Prize. In 1990 he was the chief organizer of the ICM in Kyoto. He is one of the editors of the Communications in Mathematical Physics and founder of Reviews in Mathematical Physics. In 2012 he became a fellow of the American Mathematical Society.

List of Fellows of the Royal Society elected in 1963

Fellows of the Royal Society elected in 1963.

Oldstone Conference

The Oldstone Conference of 11 to 14 April 1949 was the third of three postwar conferences held to discuss quantum physics; arranged for the National Academy of Sciences by J. Robert Oppenheimer, who was again chairman. It followed the Shelter Island Conference of 1947 and the Pocono Conference of 1948. There were 24 participants; new participants were Robert Christie, Freeman Dyson (whose writings explained Feynman’s ideas), George Placzek, and Hideki Yukawa.Held at Oldston-on-the-Hudson in Peekskill, New York, the main talking-point was Richard Feynman’s approach to quantum electrodynamics (QED); Feynman was now (at 30) the leading physicist of his generation.

Osaka Science Museum

The Osaka Science Museum (大阪市立科学館, Ōsaka Shiritsu Kagakukan) is a science museum in Naka-no-shima, Kita-ku, Osaka, Japan. The museum is located between the Dōjima River and the Tosabori River, above Osaka's subterranean National Museum of Art. Opened in 1989, the museum was constructed to mark the 100th anniversary of Osaka City. The construction was funded through a 6.5 billion yen donation toward building costs from Kansai Electric. Its theme is "The Universe and Energy". Before the war a similar museum opened in 1937. It was known as the Osaka City Electricity Science Museum and it was both the first science museum and the first planetarium in Japan.

The Science Museum's primary permanent exhibition consists of four floors of mainly interactive science exhibits, totaling 200 items, with each floor focusing on a different theme. There is also a live science show with science demonstrations several times per day. Like the rest of the museum, these demonstrations are in Japanese only and visitors may require prior scientific knowledge to enjoy them.

The two secondary exhibits, both available separately from the primary exhibit, are a planetarium, which has a dome with a radius of 26.5 meters, the 7th largest in the world which projects the images of the heavens. In July 2004, the planetarium reopened after a renovation displaying the entire night sky as a next-generation digital image.

The museum also houses a collection of scientific resources, including

Japan's first planetarium (a Carl Zeiss II model)

the Cockcroft-Walton accelerator

resources related to Seimikyoku, Japan's first full-fledged chemistry laboratory

pre-war electrical measuring devicesIts collection of books and magazines for a general audience, largely on astronomy, is the most comprehensive in West Japan.

The science building is the place where Hideki Yukawa created his theory on mesons, for which he was awarded a Nobel prize. At the time this building was part of Osaka University. It was also the first place in Japan where radio waves from the universe were measured.

Osaka University

Osaka University (大阪大学, Ōsaka daigaku), or Handai (阪大, Handai), is a public research university located in Osaka Prefecture, Japan. Osaka University is one of Japan's National Seven Universities and is generally considered one of Japan's most prestigious institutions of higher learning. It is usually ranked among the top three public universities in Japan, along with the University of Tokyo and Kyoto University. It is ranked third overall among Japanese universities and 67th worldwide in the 2019 QS World University Rankings.

The Japanese Ministry of Education, Culture, Sports, Science and Technology has classified Osaka University as a leading university in the Top Global University Project. The ministry also selected Osaka University as a Designated National University Corporation in 2018.Osaka University was the sixth modern university in Japan at its founding in 1931. However, the history of the institution includes much older predecessors in Osaka such as the Kaitokudō founded in 1724 and the Tekijuku founded in 1838.

Numerous prominent scholars and scientists have attended or worked at Osaka University, such as Nobel Laureate in Physics Hideki Yukawa, manga artist Osamu Tezuka, Lasker Award winner Hidesaburō Hanafusa, author Ryōtarō Shiba, and discoverer of regulatory T cells Shimon Sakaguchi.


In particle physics, a pion (or a pi meson, denoted with the Greek letter pi: π) is any of three subatomic particles: π0, π+, and π−. Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the lightest mesons and, more generally, the lightest hadrons. They are unstable, with the charged pions π+ and π− decaying with a mean lifetime of 26.033 nanoseconds (2.6033×10−8 seconds), and the neutral pion π0 decaying with a much shorter lifetime of 8.4×10−17 seconds. Charged pions most often decay into muons and muon neutrinos, while neutral pions generally decay into gamma rays.

The exchange of virtual pions, along with vector, rho and omega mesons, provides an explanation for the residual strong force between nucleons. Pions are not produced in radioactive decay, but commonly are in high energy collisions between hadrons. Pions also result from some matter-antimatter annihilation events. All types of pions are also produced in natural processes when high energy cosmic ray protons and other hadronic cosmic ray components interact with matter in Earth's atmosphere. In 2013, the detection of characteristic gamma rays originating from the decay of neutral pions in two supernova remnants has shown that pions are produced copiously after supernovas, most probably in conjunction with production of high energy protons that are detected on Earth as cosmic rays.The concept of mesons as the carrier particles of the nuclear force was first proposed in 1935 by Hideki Yukawa. While the muon was first proposed to be this particle after its discovery in 1936, later work found that it did not participate in the strong nuclear interaction. The pions, which turned out to be examples of Yukawa's proposed mesons, were discovered later: the charged pions in 1947, and the neutral pion in 1950.

Progress of Theoretical and Experimental Physics

Progress of Theoretical and Experimental Physics is a monthly peer-reviewed scientific journal published by Oxford University Press on behalf of the Physical Society of Japan. It was established as Progress of Theoretical Physics in July 1946 by Hideki Yukawa and obtained its current name in January 2013.

Progress of Theoretical and Experimental Physics is part of the SCOAP3 initiative.

Science and technology in Romania

On May 14, 1981 Romania became the 11th country in the world to have an astronaut in space. That astronaut, Dumitru Prunariu is today's president of Romanian Space Agency.

Henri Coandă was a Romanian inventor and pioneer of aviation. He discovered the Coanda effect of fluidics.

George Emil Palade is a Romanian-born cell biologist who won the Nobel Prize in Physiology or Medicine in 1974 for his study of internal organization of such cell structures as mitochondria, chloroplasts, the Golgi apparatus, and for the discovery of the ribosomes. He also won the National Medal of Science in 1986.

George Constantinescu created the theory of sonics, while Lazăr Edeleanu was the first chemist to synthesize amphetamine and also invented the modern method of refining crude oil.

Several mathematicians distinguished themselves as well, among them: Acad. Gheorghe Țițeica, Spiru Haret, Acad. Grigore Moisil (multi-valued logics), Acad. Miron Nicolescu, Acad. Nicolae Popescu (category theory applications to rings and modules, and number theory; Popesco-Gabriel Theorem), George Georgescu (Łukasiewicz logic algebras in categories), Florin Boca (quantum groups and C*-algebras), Liliana Elena Popescu (category theory and computing/modelling theory), Madalina Buneci (groupoid and double groupoid representations) and Ştefan Odobleja; the latter is also regarded as the ideological father behind cybernetics.

Notable Romanian physicists and inventors also include: Horia Hulubei in atomic physics, Șerban Țițeica in theoretical physics, especially thermodynamics and statistical mechanics, Mihai Gavrilă in quantum theory, Alexandru Proca known for the first meson theory of nuclear forces and Proca's equations of the vectorial mesonic field, formulated independently of the pion theory of Nobel laureate Hideki Yukawa (who predicted the existence of the pion in 1947), Ştefan Procopiu known for the first theory of the magnetic moment of the electron in 1911 (now known as the Bohr-Procopiu magneton), Theodor V. Ionescu- the inventor of a multiple-cavity magnetron in 1935, a hydrogen maser in 1947, 3D imaging for cinema/television in 1924, quantum emission in hot plasmas and hot deuterium plasma beams for controlled nuclear fusion in 1969, Ionel Solomon known for the nuclear magnetic resonance theory in solids in 1955, Solomon equations, solid state physics, semiconductors in 1979, and photovoltaics since 1988, Mircea Sabău and Florentina I. Mosora known for their contributions to Nuclear Medicine, Petrache Poenaru, Nicolae Teclu and Victor Toma, with the latter known for the invention and construction of the first Romanian computer, the CIFA-1 in 1955. At the beginning of the second millennium, there was a boom in Romania in the number of computer programmers. Romania is reported to be among the countries with the highest number of computer programmers in the world. Some examples of successful software include RAV (Romanian AntiVirus) which was bought in 2003 by Microsoft for use in their development of Windows Defender; or BitDefender which is considered the number one antivirus software and internet security software at TopTenReviews.

Shoichi Sakata

Shoichi Sakata (坂田 昌一, Sakata Shōichi, 18 January 1911 – 16 October 1970) was a Japanese physicist who was internationally known for theoretical work on the subatomic particles. He proposed the two meson theory, the Sakata model (an early precursor to the quark model), and the Maki-Nakagawa-Sakata theory on the neutrino mixings.

After the end of World War II, he joined other physicists in campaigning for the peaceful uses of nuclear power.

Yoshio Nishina

Yoshio Nishina (仁科 芳雄, Nishina Yoshio, December 6, 1890 – January 10, 1951) was a Japanese physicist. He was called "the founding father of modern physics research in Japan". He led the efforts of Japan to develop an atomic bomb during World War II.


Yukawa (written: 湯川) is a Japanese surname, but is also applied to proper nouns.

Yukawa Institute for Theoretical Physics

The Yukawa Institute for Theoretical Physics (基礎物理学研究所, kiso butsurigaku kenkyūsho) is a research institute in the field of theoretical physics, attached to Kyoto University in Japan. It was inaugurated in 1952.

While the center is often referred to as "YITP", this can be confusing as YITP also stands for the C. N. Yang Institute for Theoretical Physics at Stony Brook University in the United States.

Yukawa interaction

In particle physics, Yukawa's interaction or Yukawa coupling, named after Hideki Yukawa, is an interaction between a scalar field ϕ and a Dirac field ψ of the type

(scalar) or (pseudoscalar).

The Yukawa interaction can be used to describe the nuclear force between nucleons (which are fermions), mediated by pions (which are pseudoscalar mesons). The Yukawa interaction is also used in the Standard Model to describe the coupling between the Higgs field and massless quark and lepton fields (i.e., the fundamental fermion particles). Through spontaneous symmetry breaking, these fermions acquire a mass proportional to the vacuum expectation value of the Higgs field.

Physiology or Medicine

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