Yukawa Mind

People associated with Hideki Yukawa and Osaka University

Yoichiro Nambu learning from the pioneers of elementary particle physics


Yoichiro Nambu

(1921 to 2015, Winner of Nobel Prize in Physics, December 2008)

Yoichiro Nambu stated as follows in his lecture, “The Road I Have Taken,” at the meeting held in commemoration of his winning of the Nobel Prize in Physics on May 13, 2009 at Osaka University Graduate School of Science.

“Yukawa’s theory was announced and the name Yukawa became famous worldwide when I was a student in the secondary school. I had no idea what Yukawa’s theory was about at that time, but I was stimulated by his achievement. Partly because of that influence, when I was in Daiichi High School (presently University of Tokyo Komaba Campus), I liked mathematics but I also enjoyed making things and dealing with the ‘real’ things. So, eventually I chose Physics as my main subject of study.”

“Although I was admitted to Tokyo Imperial University in 1940, there was no program for learning the theory of elementary particles in that university at that time. Fortunately, Tokyo university of arts and sciences and RIKEN, where Dr. Tomonaga worked, were nearby, so I went there to learn the theory of elementary particles little by little. However, the war broke out and I was compelled to leave the university earlier and drafted into the military.”


Later, Nambu often mentioned the following at Osaka University: “The existence of the new particles called meson was predicted for the first time by Dr. Yukawa who was a theoretical researcher. The accelerator capable of producing high-level energy to enable necessary experiments for verifying Dr. Yukawa’s prediction was invented by Lawrence. I personally think that Yukawa and Lawrence were the pioneers of elementary particle physics.”


Nambu’s association with Osaka University started near the end of the second world war. After graduating earlier than scheduled during the war, Nambu was conscripted by the army and assigned to the radar research facility located in Takarazuka, where he met Koji Fushimi, Ryoyu Uchiyama, Hidetsugu Yagi and Kinjiro Okabe, who were Advisors at Osaka Imperial University. Nambu met Chieko and married her at about that time. Nambu resided at University of Tokyo for three years after the war and joined Jiro Koba’s Group that was studying Tomonaga’s theory. In 1949, Nambu became an associate professor at Osaka City University, and then promoted to professor in the following year. He became a member of the Institute for Advanced Study in Princeton in 1952 and a member of the University of Chicago in 1954.


Nambu loved the University of Chicago, which was located in the Midwest region of the United States, not in the East Coast or West Coast, as if it were his second home. After the emergence of the superconductivity theory, Nambu constructed and introduced many theories and the like that later guided the trend of elementary particle physics, such as the theory of spontaneous symmetry breaking, clarification of the mass generation mechanisms of protons and neutrons that make up all matter in the universe, discovery of the color freedom of quarks, proposal of SU(3) color gauge theory, which was the basic theory of the strong interaction and development of the formula for the string theory that described elementary particles as strings. Nambu’s theories were always 10 years ahead of the time.


From 1990, Nambu often stayed at Osaka University as an invited professor. In the 2000s, he built a house in Toyonaka City and spent about three months a year conducting research at Osaka University. Nambu received a Nobel Prize in Physics in December 2008. In the following year, Nambu stated in the commemorative lecture, “The Road I Have Taken”: “One should not forget that physics is fun.” He said emphatically, “It is important to keep in mind that you cherish your individualities and reflect them in your work and whatever you do.”


Nambu moved from Chicago to Toyonaka and became a distinguished professor emeritus of Osaka University in 2011. He also took active part in the educational community activities as an honorary citizen of Toyonaka City. Although he was receiving dialysis in his later years, he gave a lecture, “A New Look at Fluid Dynamics,” at the international symposium held at Osaka University on December 17, 2013. He enjoyed research and continued engaging himself in advanced research all his life.

Written by Yutaka Hosotani (Osaka University)


Yoichiro Nambu giving the lecture, “The Road I Have Taken,” in the meeting held in commemoration of his Nobel Prize in Physics on May 13, 2009 at Osaka University Graduate School of Science



In the front row, Hideki Yukawa at the second from the left, Shin-ichiro Tomonaga at the third from the left, and Shoichi Sakata at the right end

In the back row, Yoichiro Nambu at the right end and Ryoyu Uchiyama at the second from the left

Photos courtesy of Yoichiro Nambu



At The Museum of Ceramic Art, Hyogo (in Sasayama), May 2009

Photo by Yutaka Hosotani