Department of Physics Osaka University
SETSUKO TAJIMA, KOHJI HASHIMOTO, KAZUHIKO KUROKI AND YOSHITAKA KUNO
DEPARTMENT OF PHYSICS, OSAKA UNIVERSITY
The Department of Physics at Osaka University was established in 1931 when Osaka University was founded as the sixth imperial university in Japan. The first president of Osaka University was Dr. Hantaro Nagaoka, a prominent physicist who proposed a planetary model for atoms before Rutherford. His motto, "Originality and Inspiration," epitomizes the spirit of our university. Our former faculty members include Hidetsugu Yagi, who invented the Yagi antenna, and Seiichi Kikuchi, who demonstrated electron diffraction and also constructed the first cyclotron in Japan. Hideki Yukawa created his meson theory for nuclear forces when he was a lecturer at our department. He was given a PhD by Osaka University for this work, and this work later made him the first Nobel laureate in Japan. Other prominent professors in recent years include Takeo Nagamiya and Junjiro Kanamori, who established the theory of magnetism, and Ryoyu Uchiyama, who developed gauge theory.
After World War II, our department expanded to cover a wide range of physics, including experimental and theoretical elementary particle and nuclear physics, condensed matter physics, theoretical quantum physics, and interdisciplinary physics. As one of the leading universities in Japan, our mission is to serve the people of Japan and the world through education and outreach.
In the Graduate School of Science, there are two departments related to physics; they are the Department of Physics and the Department of Earth and Space Science. The faculty members of these two departments are responsible for the education of undergraduate students (about 310) at the Department of Physics in the School of Science.
Here we introduce only the Department of Physics in the Graduate School of Science. As of December 2016, we have 94 faculty members and 239 students (146 enrolled in the master's course and 93 enrolled in the doctoral course), including 44 international students. Most of the international students are enrolled in the International Physics Course (IPC), which was founded in 2010 to offer classes in English.
Among 94 faculty members, about half are in the laboratories of the Department of Physics at Toyonaka Campus, while the remainder are in groups at research centers and institutes (e.g., the Research Center for Nuclear Physics, the Institute of Laser Engineering, the Cybermedia Center, the Institute of Scientific and Industrial Research, the Advanced High Magnetic Field Research Center and the Graduate School of Frontier Biosciences), some of which are located at Suita Campus.
The building of the Department of Physics near the main gate of Toyonaka Campus.
Theoretical particle and nuclear physics
What is the origin of matter? How was the universe born? What does spacetime consist of? Such fundamental questions are explored at Osaka University. The history of the theoretical particle / nuclear physics groups dates back to Hideki Yukawa, Hantaro Nagaoka, Ryoyu Uchiyama, Yoichiro Nambu and others, all of whom explored these questions in various manners at Osaka University.
Current research topics include superstring theory, models beyond the standard model of elementary particles, quantum field theories, black holes and cosmology, quark and gluon physics, hadron physics, and interdisciplinary subjects with condensed matter physics and mathematics. Each group (categorized formally to five groups) and individual researchers form the hubs of international networks of theoretical research.
Left : A discussion at Hideki Yukawa's black board, which is installed in the public space of the department.
Right : Nambu Hall, construction complete in January 2017.
Experimental particle and nuclear physics
Research in experimental particle and nuclear physics is carried out in four research groups in the physics department, and in collaboration with the Research Center for Nuclear Physics (RCNP) and the Institute of Laser Engineering (ILE) at Osaka University.
The research subjects of the four groups are unique and are selected in such a way that small groups in universities can take a leading role in a field where very large-scale projects are prominent. They range from the search for charged-lepton-flavor-violating muons to electron conversion (in the COMET experiment at J-PARC), the search for the rare neutral kaon decay (in the KOTO experiment at J-PARC), high energy frontier physics (in the ATLAS collaboration at the Large Hadron Collider in CERN), the search for neutrino-less double beta decays (in the CANDLES experiment at Kamioka) and studies of exotic nuclear structure (at the Radioactive Isotope Beam Factory (RIBF) at RIKEN and TRIUMF).
The Research Center for Nuclear Physics (RCNP) has a 400 MeV proton cyclotron with 1 μA in beam current, and the Institute of Laser Engineering (ILE), has highly intense laser systems, GEKKO-XII and LFEX. The research topics of the former are quark-nuclear reactions with high sensitivity spectrometers, whereas the research topics of the latter are nuclear laser fusion and relativistic plasma physics. Both of the facilities are designated as joint usage/research centers in Japan.
Left: Detector of the KOTO experiment at J-PARK. Right: Detector to study exotic nuclei at TRIUMF.
Theoretical condensed matter physics
Research of theoretical condensed matter physics at Osaka University was initiated by Takeo Nagamiya and Junjiro Kanamori, who were world-renowned pioneers of the theory of magnetism. Today, some topics of primary interest include correlated electron systems, superconductivity, electron-hole systems, topological materials, disordered systems, graphene and other atomic layers.
The importance of correlation effects in condensed matter physics has been appreciated from the early days of the study of magnetism. In addition to this, currently, the significance of peculiar electronic structures that result in non-trivial topological properties, or exotic phase transitions, has become more and more recognized. Reflecting this trend, theoretical studies in the physics department take various forms such as model-based calculations, first-principles electronic structure calculations on actual materials, or combinations of the two approaches. Serious consideration of both the realistic physical setup and the correlation effects enables the theoretical studies to have more direct relevance to the experimental results, and this direction of study aims towards the ideal style of theoretical condensed matter physics pursued by Nagamiya and Kanamori.
Left: Electronic band structure of graphene with massless Dirac cones.
Right: Schematic phase diagram of superconductivity and antiferromagnetism in the iron pnictides based on a theoretical study.
Experimental condensed matter physics
For experimental condensed matter physics, there are eight research groups, covering a wide range of research subjects such as strongly correlated electronic systems, exotic superconductivity, mesoscopic physics, topological matters, nano-structure materials, organic and inorganic materials, mass spectrometer physics, and quantum spin systems. The Advanced High Magnetic Field Research Center provides ultra-high magnetic fields up to 70 tesla for researchers all over Japan to observe new phenomena and explore condensed matter physics.
All research groups are conducting experiments by using the advanced equipment and facilities at their own laboratories, and there are also large scale facilities such as the synchrotron at SPring-8 at Harima, UV-SOR at Okazaki, Photon Factory and the neutron source of KEK at Tsukuba, etc.
Left: Magnetic field dependence of resistance of phthalocyanine. Right: Electron interferometer fabricated on AlGaAs/GaAs heterostructure.
THE INTERNATIONAL PHYSICS COURSE AND THE SPECIAL HONOR COURSE
For the International Physics Course, several students are selected via biannual entrance examination for master's or doctoral courses. Students can start these courses either in October or in April. All the lectures are given in English. Students in this course are supported by tutors and office staff members. Many activities such as excursions and year-end parties, etc. are organized for international students.
In 2013, we started a special honor course. Some select students are taking this five-year PhD course and are supported by scholarships. They are required to take lectures in research fields other than their field of specialty and they must complete an internship at companies as well as at overseas universities. Through this program, students can expand their horizons. After finishing the course, we are expecting students to pursue careers not only in academia but also in industry or administrative organizations.
As one of the top universities in Japan, we are welcoming ambitious and talented students from all over the world, as well as fruitful collaboration with researchers in the world.
Setsuko Tajima received her PhD in engineering in 1988 from the University of Tokyo after working at NEC for two years and at the University of Tokyo (as an assistant researcher) for four years. She then spent three years as an assistant professor and later became a lecturer at the University of Tokyo. In 1989, she moved to the Superconductivity Research Laboratory at the International Superconductivity Technology Center (ISTEC) and worked there for 15 years. She joined the Department of Physics at Osaka University in 2004 as a full professor. Her primary interest is condensed matter physics and in particular, the mechanisms of metal-insulator transitions and high temperature superconductivity. She has been chair of the Department of Physics since 2015 and will be the dean of the Graduate School of Science from 2017.
Koji Hashimoto received his PhD in physics in 2000 from Kyoto University. He joined the University of Tokyo as an assistant professor in 2001, and led the mathematical physics laboratory at RIKEN from 2007. He became a full professor of elementary particle theory at Osaka University in 2012. His research interest is superstring theory and its application to general physics. He has been a deputy chair of the Department of Physics since 2015.
Kazuhiko Kuroki received his PhD in physics in 1994 from the University of Tokyo. He joined the Department of Physics at Osaka University in 2013 as a full professor. He has primarily worked on the theory of superconductivity and thermoelectrics in materials such as oxides, pnictides, and organic conductors. He has been a deputy chair of the Department of Physics since 2015.
Yoshitaka Kuno received his PhD in physics in 1984 from the University of Tokyo. After working at TRIUMF in Canada as a postdoc and then as a research assistant, he moved to the High Energy Accelerator Research Organization (KEK) in 1992 as an associate professor. He joined Osaka University as a full professor in 2000. He was a distinguished guest researcher at the Institute of High Energy Physics (IHEP) in Beijing, Pierre and Marie Curie University (UPMC) in France, the Institute of Basic Science (IBS) in Korea, and Technische Universität Dresden (TU Dresden) in Germany. His research interest is experimental particle physics with muons and neutrinos. He is the principle investigator of the international Coherent Muon to Electron Transition (COMET) experiment, which aims to search for muon to electron conversion in muonic atoms at J-PARC.