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Shin'ichirō Tomonaga | |
---|---|

Born | Tokyo, Japan | March 31, 1906

Died | July 8, 1979 73) Tokyo, Japan | (aged

Alma mater | Kyoto Imperial University |

Known for | Quantum electrodynamics Schwinger–Tomonaga equation |

Awards | Asahi Prize (1946) Lomonosov Gold Medal (1964) Nobel Prize in Physics (1965) |

Scientific career | |

Fields | Theoretical physics |

Institutions | Leipzig University Institute for Advanced Study Tokyo University of Education RIKEN University of Tokyo |

**Shinichiro Tomonaga**^{ [1] }(朝永 振一郎*Tomonaga Shin'ichirō*, March 31, 1906 – July 8, 1979), usually cited as **Sin-Itiro Tomonaga** in English,^{ [2] } was a Japanese physicist, influential in the development of quantum electrodynamics, work for which he was jointly awarded the Nobel Prize in Physics in 1965^{ [3] } along with Richard Feynman and Julian Schwinger.

**Japan** is an island country in East Asia. Located in the Pacific Ocean, it lies off the eastern coast of the Asian continent and stretches from the Sea of Okhotsk in the north to the East China Sea and the Philippine Sea in the south.

A **physicist** is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate causes of phenomena, and usually frame their understanding in mathematical terms. Physicists work across a wide range of research fields, spanning all length scales: from sub-atomic and particle physics, through biological physics, to cosmological length scales encompassing the universe as a whole. The field generally includes two types of physicists: experimental physicists who specialize in the observation of physical phenomena and the analysis of experiments, and theoretical physicists who specialize in mathematical modeling of physical systems to rationalize, explain and predict natural phenomena. Physicists can apply their knowledge towards solving practical problems or to developing new technologies.

In particle physics, **quantum electrodynamics** (**QED**) is the relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quantum mechanics and special relativity is achieved. QED mathematically describes all phenomena involving electrically charged particles interacting by means of exchange of photons and represents the quantum counterpart of classical electromagnetism giving a complete account of matter and light interaction.

Tomonaga was born in Tokyo in 1906. He was the second child and eldest son of a Japanese philosopher, Tomonaga Sanjūrō. He entered the Kyoto Imperial University in 1926. Hideki Yukawa, also a Nobel Prize winner, was one of his classmates during undergraduate school. During graduate school at the same university, he worked as an assistant in the university for three years. In 1931, after graduate school, he joined Nishina's group in RIKEN. In 1937, while working at Leipzig University (Leipzig), he collaborated with the research group of Werner Heisenberg. Two years later, he returned to Japan due to the outbreak of the Second World War, but finished his doctoral degree (Dissertation PhD from University of Tokyo) on the study of nuclear materials with his thesis on work he had done while in Leipzig.^{ [4] }

**Tokyo**, officially **Tokyo Metropolis**, one of the 47 prefectures of Japan, has served as the Japanese capital since 1869. As of 2014, the Greater Tokyo Area ranked as the most populous metropolitan area in the world. The urban area houses the seat of the Emperor of Japan, of the Japanese government and of the National Diet. Tokyo forms part of the Kantō region on the southeastern side of Japan's main island, Honshu, and includes the Izu Islands and Ogasawara Islands. Tokyo was formerly named Edo when *Shōgun* Tokugawa Ieyasu made the city his headquarters in 1603. It became the capital after Emperor Meiji moved his seat to the city from Kyoto in 1868; at that time Edo was renamed Tokyo. Tokyo Metropolis formed in 1943 from the merger of the former Tokyo Prefecture and the city of Tokyo. Tokyo is often referred to as a city but is officially known and governed as a "metropolitan prefecture", which differs from and combines elements of a city and a prefecture, a characteristic unique to Tokyo.

A **philosopher** is someone who practices philosophy, which involves rational inquiry into areas that are outside either theology or science. The term "philosopher" comes from the Ancient Greek, φιλόσοφος (*philosophos*), meaning "lover of wisdom". The coining of the term has been attributed to the Greek thinker Pythagoras.

**Tomonaga Sanjūrō** was a Japanese philosopher and a renowned professor emeritus of the Medieval, Renaissance, Early Modern, and Kantian philosophy at the University of Kyoto in early 20th century. He was one of the leading thinkers from the Kyoto School. His son, Shinichirō Tomonaga, is also famous for receiving the Nobel Prize in Physics in 1965 for the development of quantum electrodynamics.

In Japan, he was appointed to a professorship in the Tokyo University of Education (a forerunner of Tsukuba University). During the war he studied the magnetron, meson theory, and his super-many-time theory. In 1948, he and his students re-examined a 1939 paper by Sidney Dancoff that attempted, but failed, to show that the infinite quantities that arise in QED can be canceled with each other. Tomonaga applied his super-many-time theory and a relativistic method based on the non-relativistic method of Wolfgang Pauli and Fierz to greatly speed up and clarify the calculations. Then he and his students found that Dancoff had overlooked one term in the perturbation series. With this term, the theory gave finite results; thus Tomonaga discovered the renormalization method independently of Julian Schwinger and calculated physical quantities such as the Lamb shift at the same time.

In particle physics, **mesons** are hadronic subatomic particles composed of one quark and one antiquark, bound together by strong interactions. Because mesons are composed of quark subparticles, they have physical size, notably a diameter of roughly one femtometer, which is about 1.2 times the size of a proton or neutron. All mesons are unstable, with the longest-lived lasting for only a few hundredths of a microsecond. Charged mesons decay to form electrons and neutrinos. Uncharged mesons may decay to photons. Both of these decays imply that color is no longer a property of the byproducts.

**Sidney Michael Dancoff** was an American theoretical physicist best known for the Tamm–Dancoff approximation method and for nearly developing a renormalization method for solving quantum electrodynamics (QED).

**Wolfgang Ernst Pauli** was an Austrian-born Swiss and American theoretical physicist and one of the pioneers of quantum physics. In 1945, after having been nominated by Albert Einstein, Pauli received the Nobel Prize in Physics for his "decisive contribution through his discovery of a new law of Nature, the exclusion principle or Pauli principle". The discovery involved spin theory, which is the basis of a theory of the structure of matter.

In the next year, he was invited by Robert Oppenheimer to work at the Institute for Advanced Study in Princeton. He studied a many-body problem on the collective oscillations of a quantum-mechanical system. In the following year, he returned to Japan and proposed the Tomonaga–Luttinger liquid. In 1955, he took the leadership in establishing the Institute for Nuclear Study, University of Tokyo.^{ [4] } In 1965, he was awarded the Nobel Prize in Physics, with Julian Schwinger and Richard P. Feynman, for the study of QED, specifically for the discovery of the renormalization method. He died of throat cancer in Tokyo in 1979.

The **Institute for Advanced Study** (**IAS**) in Princeton, New Jersey, in the United States, is an independent, postdoctoral research center for theoretical research and intellectual inquiry founded in 1930 by American educator Abraham Flexner, together with philanthropists Louis Bamberger and Caroline Bamberger Fuld.

**Princeton** is a municipality with a borough form of government in Mercer County, New Jersey, United States, that was established in its current form on January 1, 2013, through the consolidation of the Borough of Princeton and Princeton Township. As of the 2010 United States Census, the municipality's population was 28,572, reflecting the former township's population of 16,265, along with the 12,307 in the former borough.

The **many-body problem** is a general name for a vast category of physical problems pertaining to the properties of microscopic systems made of a large number of interacting particles. *Microscopic* here implies that quantum mechanics has to be used to provide an accurate description of the system. A *large number* can be anywhere from 3 to infinity, although three- and four-body systems can be treated by specific means and are thus sometimes separately classified as few-body systems. In such a quantum system, the repeated *interactions* between particles create quantum correlations, or entanglement. As a consequence, the wave function of the system is a complicated object holding a large amount of information, which usually makes exact or analytical calculations impractical or even impossible. Thus, many-body theoretical physics most often relies on a set of approximations specific to the problem at hand, and ranks among the most computationally intensive fields of science.

Tomonaga was married in 1940 to Ryōko Sekiguchi. They had two sons and one daughter. He was awarded the Order of Culture in 1952, and the Grand Cordon of the Order of the Rising Sun in 1976.

In recognition of three Nobel laureates' contributions, the bronze statues of Shin'ichirō Tomonaga, Leo Esaki, and Makoto Kobayashi was set up in the Central Park of Azuma 2 in Tsukuba City in 2015.^{ [5] }

**Reona Esaki**, also known as **Leo Esaki**, is a Japanese physicist who shared the Nobel Prize in Physics in 1973 with Ivar Giaever and Brian David Josephson for his discovery of the phenomenon of electron tunneling. He is known for his invention of the Esaki diode, which exploited that phenomenon. This research was done when he was with Tokyo Tsushin Kogyo. He has also contributed in being a pioneer of the semiconductor superlattices.

**Makoto Kobayashi** is a Japanese physicist known for his work on CP-violation who was awarded one fourth of the 2008 Nobel Prize in Physics "for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature."

- 1946 – Asahi Prize
- 1948 – Japan Academy Prize
- 1951 – Member of the Japan Academy
- 1952 – Order of Culture
- 1964 – Lomonosov Gold Medal
- 1965 – Nobel Prize in Physics
- 1967 – Grand Cordon of the Order of the Rising Sun

The **Asahi Prize**, established in 1929, is an award presented by the Japanese newspaper *Asahi Shimbun* and Asahi Shimbun Foundation to honor individuals and groups that have made outstanding accomplishments in the fields of arts and academics and have greatly contributed to the development and progress of Japanese culture and society at large.

The **Japan Academy Prize** (日本学士院賞) is a prize awarded by the Japan Academy in recognition of academic theses, books, and achievements. An award ceremony has been held every year since 1911. Up to nine of these Prizes are awarded every year. There have been 676 winners and 592 winning works as of 2005. They comprise a certificate, medal, and prize money of one million yen.

The **Order of Culture** is a Japanese order, established on February 11, 1937. The order has one class only, and may be awarded to men and women for contributions to Japan's art, literature, science, technology, or anything related to culture in general; recipients of the order also receive an annuity for life. The order is conferred by the Emperor of Japan in person on Culture Day each year.

- Tomonaga, Sin-Itiro (1997).
*The Story of Spin*. Oka, Takeshi (trans.). University of Chicago Press. ISBN 0-226-80794-0.

- Tomonaga, S. "On a Relativistically Invariant Formulation of the Quantum Theory of Wave Fields."
*Prog. Theor. Phys.***1**, 27–42 (1946). - Koba, Z., Tati, T. and Tomonaga, S. "On a Relativistically Invariant Formulation of the Quantum Theory of Wave Fields. II."
*Prog. Theor. Phys.***2**, 101–116 (1947). - Koba, Z., Tati, T. and Tomonaga, S. "On a Relativistically Invariant Formulation of the Quantum Theory of Wave Fields. III."
*Prog. Theor. Phys.***2**, 198–208 (1947). - Kanesawa, S. and Tomonaga, S. "On a Relativistically Invariant Formulation of the Quantum Theory of Wave Fields. IV."
*Prog. Theor. Phys.***3**, 1–13 (1948). - Kanesawa, S. and Tomonaga, S. "On a Relativistically Invariant Formulation of the Quantum Theory of Wave Fields. V."
*Prog. Theor. Phys.***3**, 101–113 (1948). - Koba, Z. and Tomonaga, S. "On Radiation Reactions in Collision Processes. I."
*Prog. Theor. Phys.***3**, 290–303 (1948). - Tomonaga, S. and Oppenheimer, J. R. "On Infinite Field Reactions in Quantum Field Theory."
*Phys. Rev.***74**, 224–225 (1948).

**Paul Adrien Maurice Dirac** was an English theoretical physicist who is regarded as one of the most significant physicists of the 20th century.

**Richard Phillips Feynman** was an American theoretical physicist, known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics for which he proposed the parton model. For his contributions to the development of quantum electrodynamics, Feynman, jointly with Julian Schwinger and Shin'ichirō Tomonaga, received the Nobel Prize in Physics in 1965.

A timeline of atomic and subatomic physics.

**Julian Seymour Schwinger** was a Nobel Prize winning American theoretical physicist. He is best known for his work on the theory of quantum electrodynamics (QED), in particular for developing a relativistically invariant perturbation theory, and for renormalizing QED to one loop order. Schwinger was a physics professor at several universities.

**Renormalization** is a collection of techniques in quantum field theory, the statistical mechanics of fields, and the theory of self-similar geometric structures, that are used to treat infinities arising in calculated quantities by altering values of quantities to compensate for effects of their **self-interactions**. However, even if it were the case that no infinities arise in loop diagrams in quantum field theory, it can be shown that renormalization of mass and fields appearing in the original Lagrangian is necessary.

The year **1949 in science** and technology involved some significant events, listed below.

In quantum field theory, the **quantum vacuum state** is the quantum state with the lowest possible energy. Generally, it contains no physical particles. **Zero-point field** is sometimes used as a synonym for the vacuum state of an individual quantized field.

* "What Do You Care What Other People Think?": Further Adventures of a Curious Character* (1988) is the second of two books consisting of transcribed and edited, oral reminiscences from American physicist Richard Feynman. It follows

In theoretical physics, **Pauli–Villars regularization** (**P–V**) is a procedure that isolates divergent terms from finite parts in loop calculations in field theory in order to renormalize the theory. Wolfgang Pauli and Felix Villars published the method in 1949, based on earlier work by Richard Feynman, Ernst Stueckelberg and Dominique Rivier.

In particle physics, the **history of quantum field theory** starts with its creation by Paul Dirac, when he attempted to quantize the electromagnetic field in the late 1920s. Major advances in the theory were made in the 1940s and 1950s, and led to the introduction of renormalized quantum electrodynamics (QED). QED was so successful and accurately predictive that efforts were made to apply the same basic concepts for the other forces of nature. By the late 1970s, these efforts successfully utilized gauge theory in the strong nuclear force and weak nuclear force, producing the modern standard model of particle physics.

The first **Shelter Island Conference** on the Foundations of Quantum Mechanics was held from June 2–4, 1947 at the Ram's Head Inn in Shelter Island, New York. Shelter Island was the first major opportunity since Pearl Harbor and the Manhattan Project for the leaders of the American physics community to gather after the war. As Julian Schwinger would later recall, "It was the first time that people who had all this physics pent up in them for five years could talk to each other without somebody peering over their shoulders and saying, 'Is this cleared?'"

*For classical dynamics at relativistic speeds, see relativistic mechanics.*

The **Feynman checkerboard**, or **relativistic chessboard** model, was Richard Feynman’s sum-over-paths formulation of the kernel for a free spin-½ particle moving in one spatial dimension. It provides a representation of solutions of the Dirac equation in (1+1)-dimensional spacetime as discrete sums.

**Shoichi Sakata** was a Japanese physicist who was internationally known for theoretical work on the subatomic particles. He proposed the two meson theory, the Sakata model, and the Maki-Nakagawa-Sakata theory on the neutrino mixings.

**Masao Kotani** was a Japanese theoretical physicist, known for molecular physics and biophysics.

The **Pocono Conference** of 30 March to 2 April 1948 was the second of three postwar conferences held to discuss quantum physics; arranged by Robert Oppenheimer for the National Academy of Sciences. It followed the Shelter Island Conference of 1947 and preceded the Oldstone Conference of 1949.

**Peter R. Holland** is an English theoretical physicist, known for his work on foundational problems in quantum physics and in particular his book on the pilot wave theory and the de Broglie-Bohm causal interpretation of quantum mechanics.

**Norman Myles Kroll** was an American theoretical physicist, known for his pioneering work in QED.

- ↑ For this spelling see: Shigeru Nakayama, Kunio Gotō, Hitoshi Yoshioka (eds.),
*A Social History of Science and Technology in Contemporary Japan: Road to self-reliance 1952-1959*, Trans Pacific Press, 2005, p. 723. - ↑ Schweber, S. S. (1994).
*QED and the Men Who Made It: Dyson, Feynman, Schwinger, and Tomonaga*. Princeton University Press. p. 252. ISBN 9780691033273.. - ↑ Hayakawa, Satio (December 1979). "Obituary: Sin-itiro Tomonaga".
*Physics Today*.**32**(12): 66–68. Bibcode:1979PhT....32l..66H. doi:10.1063/1.2995326. - 1 2 "Sin-Itiro Tomonaga - Biographical".
*www.nobelprize.org*. Retrieved 2018-01-03. - ↑ ノーベル賞:江崎、小林、朝永氏の銅像やレリーフ設置 完成記念式でお披露目 「子どもが夢を」−−つくば・中央公園 ／茨城 - 毎日新聞 Archived 2015-04-24 at the Wayback Machine .

- Lundqvist, Stig, ed. (1998).
*Nobel Lectures in Physics (1963-1970)*. World Scientific. pp. 126–39. ISBN 981-02-3404-X. - Schweber, Silvan S. (1994).
*QED and the Men Who Made It: Dyson, Feynman, Schwinger, and Tomonaga*. Princeton University Press. ISBN 0-691-03327-7. - Tomonaga's Nobel Prize Lecture.

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