You are here: HOME > Nobel Prize > Physics

Nobel Prize

Physics

2015: Takaaki Kajita, Ph.D.

Born in 1959 in Saitama. After graduating from the Department of Physics, Faculty of Science, Saitama University in 1981, he went on to a graduate program at the University of Tokyo and studied particle physics, specifically neutrino physics under Masatoshi Koshiba and Yoji Totsuka. In 1986, Dr. Kajita started his research on atmospheric neutrinos and in 1988 he discovered the observed amount of muon neutrinos in the atmosphere is only about 60% of what is predicted by theory, and that the remaining 40% has changed into tau neutrinos. Furthermore, in 1998, the research group at Super-Kamiokande in which he worked observed that the amount of muon neutrinos decreases by about half as they travel long distances. Consequently he proved for the first time that neutrino oscillations occur. Neutrino oscillation can only occur if neutrinos have mass, so his group showed for the first time that neutrinos have mass  through a series of observations. His achievement was recognized in 2015, when he jointly received the Nobel Prize in Physics with Dr. Arthur B. McDonald, Gordon and Patricia Gray Chair in Particle Astrophysics at Queen's University.

Dr. Kajita was also awarded; the Asahi Prize as part of the Super-Kamiokande research group in 1998, the 45th Nishina Memorial Prize in 1999, the Panofsky Prize as part of the Super-Kamiokande research group in 2002, the Japan Academy Prize in 2012 etc.

2014: Isamu Akasaki, Ph.D.
Hiroshi Amano, Ph.D. and
Shuji Nakamura, Ph.D. (naturalized American citizen)

© ® Photo by Zenis.

© ® Photo by Zenis.

Isamu Akasaki was born in Chiran, Kagoshima in 1929. He graduated from the Faculty of Science at Kyoto University with a bachelor’s degree in 1952. After working as a researcher at Kobe Industries Corporation (now Fujitsu Ten Ltd.) for seven years, he served as a Research Associate, Assistant Professor, and Associate Professor at Nagoya University from 1959 to 1964. Then he joined Matsushita (now Panasonic) Research Institute Tokyo and started research on blue light-emitting diodes (LEDs). His research on developing blue LEDs continued at Nagoya University where he served as a full professor from 1981.
Hiroshi Amano was born in Hamamatsu, Shizuoka in 1960. He entered the Faculty of Engineering at Nagoya University in 1979, continued in Graduate School there (1983–1988), where Akasaki was serving as a professor, and then started research on blue LEDs under Akasaki in 1988. Shuji Nakamura was born in Yotsuhama (now Ikata), Ehime. After completing his Master’s degree in 1979 at the Graduate School of Engineering of Tokushima University, he joined Nichia Corporation and started his research on LEDs.
Akasaki and Amano established the fundamental principle of operation of blue LEDs and Nakamura developed the method and the process that enabled mass production of blue LEDs.
Red and yellow-green LEDs had been developed during the late 1950s and early 1960s. At that time there was already much interest in blue LEDs that would allow us to create sources of white light for illumination by combination of the three primary colors (red, green, blue) of light. During 1970s and 1980s, many researchers tried to create blue LEDs, but without success. It was thought that it would be impossible to make blue LEDs anytime in the 20th century. However, Akasaki and Amano overcame the considerable technical difficulties in producing a p-n junction in a gallium nitride (GaN) crystal, and presented their first bright-blue LED based on light emission in such a junction in 1989. Nakamura made it possible to mass produce blue LEDs by developing a unique process for efficiently creating high-quality GaN crystals, suitable for making blue LEDs.
By their hard work, these three men created in the blue LED, a new light source for illumination that benefits all of humanity. LED-based lights are the most energy-efficient and long-lasting light sources ever made, with much less wasted heat compared with incandescent or fluorescent lights. LEDs are now also used for tail lights in cars, traffic lights, and display screens for computers or smart phones. Furthermore, the blue-ray disc, an essential device for today’s information-oriented society, is made possible by their work.
Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura were jointly awarded the Nobel Prize in Physics 2014 "for the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources."
Akasaki is now Professor Emeritus at Meijo University and Nagoya University, and University Professor of Nagoya University. Amano is now serving as a professor at the Graduate School of Engineering of Nagoya University. Nakamura now serves as a professor at the University of California, Santa Barbara.

2008: Makoto Kobayashi , Ph.D. and Toshihide Maskawa, Ph.D.

© ® The Nobel Foundation.

© ® The Nobel Foundation.

Makoto Kobayashi was born in Aichi prefecture in 1944. He graduated from Nagoya University School of Science with a bachelor’s degree in physics in 1967. Since then he has pursued research in theoretical physics, with a particular focus on particle theory, at Kyoto University and the High Energy Accelerator Research Organization. Toshihide Maskawa was born in Aichi prefecture in 1940. He graduated from Nagoya University School of Science in 1962 with a bachelor’s degree in physics, and continued his work on particle theory at The University of Tokyo and Kyoto University. Kobayashi and Maskawa proposed that the charge-parity (CP) violation, which occurs when there is broken symmetry between particles and antiparticles, requires three generations of quarks, in other words the six types of up, down, charm, strange, top and bottom. This prediction was later confirmed through experimentation. They were awarded the 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". Today, Kobayashi is Emeritus Professor at Nagoya University and Chair of the Advisory Board of the Kobayashi-Maskawa Institute for the Origin of Particles and the Universe. Maskawa is Emeritus Professor at Nagoya University and head of the Maskawa Institute for Science and Culture at Kyoto Sangyo University.

2008: Yoichiro Nambu, Ph.D. (naturalized American citizen)

© ® The Nobel Foundation.

Yoichiro Nambu was born in Tokyo prefecture in 1921. He graduated from the Faculty of Science at the University of Tokyo with a Masters degree in physics in 1942. After the Pacific War, he returned to the University of Tokyo as a research assistant, and worked there until 1952, when he was awarded his doctorate. He then moved to the United States, where he worked at several leading centers of research, pursuing his interest in theoretical physics, and particle theory in particular. He proposed the theory of spontaneous symmetry breaking: when a quantum which is neither a particle nor an antiparticle is determining what state it will take, a spontaneous broken symmetry occurs, where there are almost no antiparticles in contrast to a large volume of particles. He was awarded the Nobel Prize in Physics for “the discovery of the mechanism of spontaneous broken symmetry in subatomic physics”. In 1970 he took American citizenship. After more than fifty years as a professor at the University of Chicago, he was Professor Emeritus at the Enrico Fermi Institute at the University of Chicago.

2002: Masatoshi Koshiba, Ph.D.

Masatoshi Koshiba was born in Aichi prefecture in 1926. After graduating from the Faculty of Science, University of Tokyo with a bachelor’s degree in physics in 1951, Koshiba moved to the United States to study at the Graduate School of the University of Rochester, where he received his Ph.D. Koshiba then returned to Japan and took up a position as Professor of the Faculty of Science at the University of Tokyo. He oversaw the construction of an enormous proton-decay detector, called KamiokaNDE, built underground in a zinc mine in Gifu prefecture. In 1987, KamiokaNDE succeeded in observing neutrinos from a supernova explosion in the Large Magellanic Cloud. Further observations proved the theory that neutrino oscillation occurs when a neutrino has non-zero mass. Koshiba was awarded the Nobel Prize in Physics for “pioneering contributions to astrophysics, in particular for the detection of cosmic neutrinos”. He continues to teach students and is currently Emeritus Professor of The University of Tokyo.

1973: Leo Esaki, Ph.D.

Leo Esaki was born in Osaka prefecture in 1925. After graduating with a bachelor’s degree in physics from The University of Tokyo in 1947, he joined Kawanishi Machinery (today part of Fujitsu). In 1956, he joined Tokyo Telecommunications Engineering (now known as Sony). There, he discovered the tunnel effect of germanium, while working on the analysis of defective germanium transistor radios, thus making a significant contribution to the functional improvement of transistor radios. Esaki was awarded a Ph.D. in Science from The University of Tokyo in 1959 for his discovery, and continued to work on higher functionality and miniaturization of radios, the popularity of which skyrocketed in the 1970s thanks to their improved performance. He received the Nobel Prize in Physics for his “experimental discoveries regarding tunneling phenomena in semiconductors and superconductors, respectively”. Today, he is President of Yokohama College of Pharmacy.

1965: Sinitiro Tomonaga, Ph.D.

Sinitiro Tomonaga was born in Tokyo prefecture in 1906. After graduating with a bachelor’s degree in physics at the Faculty of Science, Kyoto Imperial University, in 1929, he worked on research into quantum mechanics under Yoshio Nishina, known as the “father of modern Japanese physics”, at RIKEN, a comprehensive research center in science and technology. At the time, quantum mechanics was facing a serious hurdle: experimentally observed mass would be specific and discrete, but computed mass was, by contrast, infinite. In response to this problem, Tomonaga proposed the use of a renormalization procedure, paving the way for the problem to be solved. He continued to work on this renormalization procedure until his theory was complete. He was awarded the Nobel Prize in Physics for “fundamental work in quantum electrodynamics, with deep-ploughing consequences for the physics of elementary particles”. He died in 1979.

1949: Hideki Yukawa, Ph.D.

Hideki Yukawa was born in Tokyo prefecture in 1907. He received a bachelor’s degree in physics from the Faculty of Science at Kyoto Imperial University in 1929. After graduating, he began his research in theoretical physics, with a particular focus on particle theory. He subsequently worked as a lecturer and assistant professor at Kyoto Imperial University and at Osaka Imperial University. While at Osaka Imperial University, Yukawa published his seminal paper “On the Interaction of Elementary Particles”. Here, he predicted the existence of the meson, in addition to the proton and neutron which had already been proved to exist by that time, as a third component of the nucleus. This proposal established a new approach to particle theory, and Yukawa was awarded the Nobel Prize in Physics for “his prediction of the existence of mesons on the basis of theoretical work on nuclear forces”. Yukawa was the first Japanese ever to be awarded any Nobel Prize. He died in 1981.