Sin-Itiro Tomonaga

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Tokyo, Japan
Birth Sign
Tokyo, Japan

Sin’ichir Tomonaga was a Japanese physicist who shared the 1965 “Nobel Prize in Physics” with Julian Schwinger and Richard Feynman, two American theoretical physicists, for developing the basic principles of quantum electrodynamics (QED), especially for finding the renormalization method. It is the study of how charged subatomic particles and the electromagnetic field interact with each other. In the early 1940s, Tomonaga began and finished his research on quantum electrodynamics. He then published the results of his research. In quantum field theory, he came up with the idea of the covariant formulation. His work on the theory of QED made it the same as the theory of special relativity, which is a well-known theory about the relationship between space and time. But the “Second World War” kept him apart from scientists in the West, and it wasn’t until after the war that the West recognized his theoretical work on QED. Tomonaga was a physics professor at Bunrika University, President of Tokyo University of Education, and Chairman of the Japan Science Council. He fought hard against the use of nuclear weapons and insisted that money should be spent on peaceful ways to use nuclear energy. In 1952, Japan’s highest award, the “Order of Culture,” was given to him. In 1964, the Academy of Sciences of the USSR gave him the “Mikhail Lomonosov Gold Medal,” among many other awards and honors.

Early years and childhood

He was born on March 31, 1906, in Tokyo, Japan. He was the second child and first son of Tomonaga Sanjr and Hide Tomonaga. At the time he was born, his father was a philosopher and a professor at Shinshu University in Tokyo.
In 1913, his family moved to Kyoto, where his father went on to teach philosophy at Kyoto Imperial University.

Since then, he grew up in Kyoto, where he went to school at Kyoto Imperial University, Japan’s second-oldest university and one of the country’s National Seven Universities. It has given birth to ten Nobel Prize winners, including Hideki Yukawa, who was Tomonaga’s classmate when he was in college.

In 1929, he went to college and got his Rigakushi, which is a bachelor’s degree in physics. For the next three years, he worked as an assistant. His time at college, on the other hand, was not very satisfying, and he wrote about that in “My Teachers, My Friends.”

Then, in April 1932, he joined the group of Dr. Yoshio Nishina, a Japanese physicist who was known as “the founding father of modern physics research in Japan,” at the Nishina Laboratory at RIKEN, a large Japanese research institute. There, he started working on quantum electrodynamics with the help of Dr. Nishina and finished a paper on how photoelectric pairs are made.

After 1935, Dr. Nishina helped him write the first five papers about how positrons form and disappear, and the sixth paper is about how neutrons and protons interact.

He then started working at Leipzig University in Leipzig, Germany. In 1937, he joined the research team of German theoretical physicist Werner Heisenberg, who was one of the first people to study quantum mechanics.

There, he learned about quantum field theory and nuclear physics. In the journal Zeitschrift für Physik, he wrote an article called “Innere Reibung und Warmeleitfahigkeit der Kernmaterie.”

At the start of the “Second World War” in 1939, he had to go back to Japan, but he was able to finish his D. Sc., or Rigakuhakushi, a degree that same year. The “Tokyo Imperial University” chose the paper he wrote and published in Leipzig as his thesis.

Sin Tomonaga’s Career

In 1940, he focused on the meson theory and made the intermediate coupling theory to figure out how the meson cloud around the nucleon is made up.
In 1941, he was hired as a physics professor at “Tokyo Bunrika University.”
In 1944, he started teaching part-time at “Tokyo Imperial University” and also did the research for the navy.

He studied meson theory, magnetron, and his “super-many-time” theory during the “Second World War.” He worked on the theory of microwave circuits and waveguides, especially the idea of the magnetron oscillator, which is used in radar to make short radio waves. In 1948, the “Japan Academy Prize” was given to him and Masao Kotani for their work on the magnetron.

In 1948, Tomonaga and his students looked at and analyzed a paper written by Sidney Dancoff, an American theoretical physicist, in 1939. In that paper, Dancoff tried but failed to show that the infinities that come up in quantum electrodynamics can be canceled out and give finite results.

He and his students sped up and analyzed the calculations by using his super-many-time theory and a relativistic procedure based on the non-relativistic procedure of physicists Fierz and Wolfgang Pauli.

They found out that Dancoff had missed a term in the perturbation series this way. Once this mistake was fixed, Dancoff’s method gave clear results. This is how Tomonaga found the method of renormalization, which led him to make a theory about QED. During this time, he also worked out physical numbers, such as the “Lamb shift.”

In 1949, he went to Princeton, New Jersey, at the invitation of American theoretical physicist Robert Oppenheimer to work at the “Institute for Advanced Study.” There, he looked at a one-dimensional fermion system and was able to figure out how a quantum mechanical many-body system’s collective oscillations work.

In 1955, he published a simple idea about how quantum mechanical collective motions work.
He had a chair at “Columbia University” from 1949 to 1953.

After he went back to Japan in 1950, he came up with the Tomonaga-Luttinger liquid, which is a theory about how electrons interact in a one-dimensional conductor.
In 1951, he took the place of Dr. Nishina on the “Science Council of Japan.” He became President of the Council in 1963 and stayed in that job until 1969.

In 1955, he helped put together the “Institute for Nuclear Study” at the “University of Tokyo.”
In 1956, the “Tokyo University of Education” made him its President. He stayed in that job until 1962.
From 1957 on, he stayed involved in groups like the Pugwash conferences that worked to stop the spread of nuclear weapons.

He was in charge of the Institute of Optical Research at the University of Tokyo from 1963 to 1969. He was also on a number of other important government committees that worked on scientific research and policy.

The History of Nuclear Physics, Quantum Mechanics, Spin, and Quantum Field Theory is told in Tomonaga’s book Supin wa Meguru (The Story of Spin) from 1974. Quantum Mechanics, which came out in 1962, and Development of Quantum Electrodynamics: Personal Recollections are two of his other important books (1966).

He stayed a Foreign Member of the “Royal Swedish Academy of Sciences,” a Foreign Associate of the “National Academy of Science,” and a Foreign Member of the “German Academy of Sciences Leopoldina.”

Awards & Achievements

In 1965, he and Julian Schwinger and Richard Feynman were all given the “Nobel Prize in Physics.”

Personal History and Legacies

He got married to Ryoko Sekiguchi on October 27, 1940. There were two boys and a girl in the family.
Tomonaga died in Tokyo on July 8, 1979. He had throat cancer and had been sick for a long time. His body was put to rest in Tokyo’s “Tama Reien Cemetery.”

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