Elementary Particle Physics (Theoretical)
Associate Professor: Yasuda, Osamu
Assistant Professor: Kitazawa, Noriaki
Particle physics clarifies the properties (such as mass and force) of elementary particles that constitute matter in the universe. The properties of elementary particles that are known so far are described by a theory called the Standard Model. According to the Standard Model, the world is made up of three generations or six kinds of elementary particles called quarks and leptons, and they interact with each other through what are called gauge particles. At present, particle physicists are working to solve problems that cannot be explained by the Standard Model. Here at TMU, active research continues on topics such as the mass generation mechanism of elementary particles (the lightest and the heaviest weigh 0.9 and 3×105 in units of 10-30 kg, respectively, and therefore there is a huge difference in mass), and the possibility of particles called neutrinos, which hardly interact with other particles, having tiny mass and the way their mass is generated, and furthermore, unified theories of elementary particles including gravity, etc.
High Energy Physics (Theoretical)
Associate Professor: Ketov, Sergei
Theoretical high-energy physics deals with the construction of a unified theory for all fundamental physical interactions, including gravity. The best-known candidate for such a theory is the superstring theory, or its more refined version, the M-theory. The purpose of this research is the construction of a quantum theory of gravity that would also include all other known phenomena at all energy scales, including elementary particle physics and cosmology. The research activity of our subgroup at TMU focuses on investigating the structure of effective supersymmetric field theories and supergravities originating from superstrings in certain low-energy limits. We are also investigating the possible application of supergravity and superstrings on the physics of black holes and the early universe.
Nuclear Physics
Professor: Suzuki, Toru
Present-day nuclear physics covers a broad range of fields from microscopic structure of hadrons to macroscopic properties of nuclear matter under extreme conditions. The frontiers of related branches of physics such as particle, atomic, mesoscopic and astrophysics are now rapidly expanding. Our research fields accordingly cover a wide range of topics such as: spin observables in medium- and high-energy nuclear reactions; exotic phases of high-density hadronic matter; studies on the nuclear many-body problem as strongly interacting Fermi-liquid theory; and statics and dynamics of low-temperature bosonic and fermionic atomic gases.
Theoretical Astrophysics
Professor: Masai, Kuniaki
Assistant Professor: Sasaki, Shin
Astrophysics involves research and study of the various classes of objects in our universe, their structure, their origin and their evolution, based on physics that covers dynamics, statistical physics, electrodynamics, hydrodynamics, quantum physics and relativity. The major fields are High Energy Astrophysics and Observational Cosmology. The faculty is particularly interested in directing graduate research in the following subjects: physical processes in astrophysical plasmas and relativistic phenomena; X-ray binaries hosting neutron stars or black holes; supernova remnants and interstellar gas; active galactic nuclei; formation and evolution of galaxies, clusters of galaxies, and intracluster gas; and gamma-ray bursts. Graduate students may carry out their research in collaboration with the department's astrophysics group and groups from the JAXA Institute of Space and Astronautical Science and other universities.
Nonlinear Physics
Professor: Shudo, Akira
Assistant Professor: Tanaka, Atsushi
One of the greatest challenges in contemporary physics is to understand the various complex systems in nature. Nonlinear interaction between each element is a major cause of the system's complexity, and therefore the theory of nonlinear dynamics plays an important role in the approach to such issues. The main interests in our laboratory are chaotic dynamics in classical Hamiltonian systems and quantum manifestations of classical chaos (quantum chaos). In particular, we are focusing on quantum tunneling in the presence of chaos; complex WKB methods in chaotic systems; slow relaxation in Hamiltonian systems with internal degrees of freedom; chaotic open quantum systems; and formalisms on adiabatic phenomena
Condensed Matter Physics (Theoretical)
Professor: Okabe, Yutaka
Associate Professor: Mori, Hiroyuki
Assistant Professor: Otsuka, Hiromi
The materials surrounding us consist of a large number of nuclei and electrons. The various forms of these materials reflect the fact that particles interact with each other. Materials show interesting behavior that cannot be imagined from the properties of individual constituent particles. The goal of the theoretical study of condensed matter physics is to understand the various material properties based on statistical mechanics, quantum mechanics and quantum field theory to construct a systematic formulation of theory, and to predict new properties of condensed matter. Phase transitions and critical phenomena, low-dimensional quantum systems, ultra cold atoms, Bose-Einstein condensation, quantum liquids, etc. are currently under study.
Strongly Correlated Electron Physics (Theoretical)
Professor: Hotta, Takashi
The strongly correlated electron system is one of the central issues in condensed matter physics. Typical examples are f-electron systems including actinide and rare earth compounds. Other typical strongly correlated materials are transition metal oxides such as cuprate superconductors and colossal magneto-resistive manganites. In strongly correlated systems, exotic magnetism and unconventional superconductivity has been found successively. Most of theoretical studies on these systems have traditionally concentrated on simple models which ignore orbital and/or phonon degrees of freedom. However, in order to understand new magnetism and superconductivity which have been recently discovered in strongly correlated electron systems, it is essentially important to consider multi degrees of freedom such as electron orbital and lattice vibration in addition to spin and charge. In our group, we develop theoretical research on magnetism and superconductivity in the systems characterized by new elements of multi degrees of freedom in combination with traditional concept of the competition between the itinerant and localized nature of electron by exploiting both analytic and numerical techniques.
Spin Quantum Physics (Theoretical)
Associate Professor: Tatara, Gen
Spintronics aims at the control of the charge and spins, which are quantum mechanical magnets the electrons have. In spin related phenomena, the quantum mechanical and the relativistic effects are remarkably important. For instance, the most powerful magnet (Neodymium magnet), used for many kinds of devices such as computers, cars and mobile phones, is realised by use of quantum relativistic effects. The cutting-edge field of spintronics is very interesting, where novel phenomena arise due to strong coupling between the relativistic and qunatum mechanical effects in solids.
High Energy Physics Experiments
Professor: Sumiyoshi, Takayuki
Associate Professor: Kakuno, Hidekazu
Assistant Professor: Chiba, Masami
Assistant Professor: Kumita, Tetsuro
What is the ultimate structure of matter? To shed light on this question, our group has been pursuing high-energy physics utilizing accelerators as well as non-accelerator physics. The unique feature of our group is the use of the highly advanced technology of high-quality particle and laser beams. The main subjects are: 1) Bose-Einstein condensation of positronium by means of laser cooling; 2) Polarized positron beam for future e+/e- linear colliders generated through Compton scattering and successive pair creation; 3) Ultra-bright femto-second X-ray in collaboration with BNL; and 4) Electron-proton interactions at high energy using HERA at DESY.
Atomic Physics
Associate Professor: Tanuma, Hajime
Assistant Professor: Furukawa, Takeshi
The experimental atomic physics group deals with dynamics and spectroscopy in a variety of atomic collision systems. We cover a wide energy range from GeV to meV in the collision of ionic projectiles including highly charged ions, heavy molecular ions with electron, atom, molecule, and crystal targets. Our major concerns are: 1) High-energy (GeV), highly charged ion excitation through resonant coherent processes by means of periodic crystal structure; 2) Slow (keV), highly charged ion collision with atoms/molecules; 3) Slow (meV) ion collision processes and cluster ion formation in helium gas at a liquid-helium temperature; and 4) Dynamics and spectroscopy of ions including large molecular ions utilizing a liquid-nitrogen-cooled electrostatic ion storage ring combined with a tunable OPO laser (collaboration with the cluster chemistry group).
Experimental Astrophysics
Professor: Ohashi, Takaya
Associate Professor: Ishisaki, Yoshitaka
Assistant Professor: Ezoe, Yuichiro
This group performs X-ray observations of cosmic objects from scientific satellites. The objects under study include high-energy sources in our galaxy, active galaxies at cosmological distances, clusters of galaxies filled with dark matter and hot plasma, and the cosmic X-ray background. Recent sensitive observations are pushing back the frontiers into the distant universe. The group is also carrying out its hardware program: development of new observational instruments with superior energy resolution. Many activities in this group are done in collaboration with the high-energy astrophysics group at the Institute of Space and Astronautical Science and with other university groups in Japan.
Solid State Spectroscopy
Associate Professor: Ishii, Hiroyoshi
Electronic and structural properties of various materials are investigated using synchrotron radiation, lasers and laboratory x-ray sources. Because electrons and ions are bound with electromagnetic force, light as an electromagnetic wave induces many complex oscillations. These induced oscillations are analyzed by photoabsorption, reflection, photoemission and fluorescence spectroscopy, from which we derive the electronic density of states, the orbital symmetries, and the mechanism of various relaxation processes. The structure of some biological materials is analyzed using the small-angle x-ray diffraction technique. The quantum optical properties of various light sources are investigated using Young's interferometry and a two-photon correlation method.
Correlated Electron Physics
Professor: Sato, Hideyuki
Professor: Aoki, Yuji
Assistant Professor: Higashinaka, Ryuji
"Electrons" in solids show various interesting phenomena (such as superconductivity, heavy fermion and so on) resulting from a strong correlation effect. Exciting new physics has been revealed in recent years, especially in f-electron intermetallic compounds. We are now concentrating our research on filled skutterudites, a group of intermetallic compounds that demonstrate unconventional superconductivity, metal-insulator transition, and electronic multipole ordering. To find further new phenomena and to understand their attractive features, we are synthesizing high-quality single crystals of filled skutterudites and exploring new physics by measuring electrical, magnetic and thermal properties under extreme environmental conditions of ultra low temperature, high magnetic field and high pressure.
Nanoscience Research I
Professor: Maniwa, Yutaka
Assistant Professor: Nakai, Yusuke
Condensed matter has a variety of physical properties such as being insulating, metallic, semiconducting, superconducting, ferromagnetic, antiferromagnetic, etc. In this research group, magnetic resonance as a major technique along with several other experimental methods is applied to these materials with novel properties, in order to clarify their mechanism and origin from a microscopic point of view. The present projects are concerned with carbon nanotubes, and nanoclusters such as zeolites, and superconductors. The experimental facilities in this group are as follows: several magnets up to 9 T and spectrometers including solid-state magic-angle spinning for NMR.
Nanoscience Research II
Associate Professor: Yanagi, Kazuhiro
Nano-scale is located in a boundary region between atomic scale and micro-meter scale. Detailed understanding of the properties of nano-size materials and development of techniques to control their structures and functions are crucial for overcoming the limits of today's technologies. Nano-size materials are composed of several atoms or molecules. When the components are arranged in a good order, such as carbon nanotubes and photo-synthetic pigment-protein complexes, the materials exhibit quite unique properties that cannot be observed if the components are located randomly. In this laboratory, we are investigating the properties that we can observe only in the nano-scale, and developing techniques to control the properties. We produce nano-size materials in high-purity, and investigate their physical properties with laser spectroscopy and various techniques.
Neutron Scattering Subgroup
Associate Professor: Kadowaki, Hiroaki
Assistant Professor: Takatsu, Hiroshi
We are investigating the dynamical, magnetic and structural properties of condensed matter using neutron and x-ray scattering techniques. These scattering experiments utilizing particle beams with wavelength of a few angstroms are intriguing and unique, because they directly provide microscopic information about condensed matter. Our research interests center on quantum phase transitions, geometrically frustrated systems, and low dimensional properties of atoms and molecules in carbon nanotubes. Experiments are performed in collaboration with several research groups around the world.
Material Physics with ESR
Professor: Mizoguchi, Kenji
Assistant Professor: Sakamoto, Hirokazu
We are investigating the electronic states of organic (mainly conducting) materials such as conducting polymer, charge-transfer complexes and DNA, characterized by low dimensional π electron systems with strong electron-electron correlation. The magnetic measurements, especially Electron Spin Resonance in the wide parameter ranges of frequency (0.01-94 GHz), pressure (3 GPa, in the near future, up to 10 GPa) and temperature (2-400 K) could be utilized for this purpose, along with SQUID susceptometer, electric conductivity, structural analysis by X-ray and AFM/STM, and electron microscopy.
