Physics of Collective Phenomena Basic Complexity Science High-temperature ionized gas (plasma) exhibits a variety of collective phenomena. In our group, studies of magnetohydrodynamic (MHD) instabilities, heating and current drive by high-frequency waves, transport processes of energy and particles, as well as research and development of advanced diagnostics are being carried out. In addition, we have active collaborations on world-leading large fusion plasma devices such as JT-60U (JAERI) and LHD (NIFS). Through these activities we aim at comprehensive understanding of collective phenomena in high-temperature plasmas. Our group are studying the mathematical theory of information and complexity. The examples of the research subjects are as follows: (1) Information theory : Shannon Theory, data compression algorithms, error correcting code, network coding, coding and applications, (2) Information security and cryptology : Information-theoretic security theory, secret sharing scheme, coding of wiretap channel, bit commitment, public key cryptosystem, algorithmic number theory. Professor: Yuichi Takase Associate Professor: Akira Ejiri Professor: Hirosuke Yamamoto Associate Professor: Noboru Kunihiro Advanced Nuclear Fusion Plasma Computation and Complexity Nuclear fusion will occur in plasmas (hot ionized gases) under the appropriate temperature, density, and confinement conditions in a magnetic field. To develop smaller, more economical fusion reactors, we are researching the confinement of a higher plasma pressure for a given magnetic field strength (high-beta plasma confinement). The research issues are as follows; 1) development of ultra high-beta confinement concepts such as field-reversed configuration and spherical tokamak, 2) application of plasma merging technique on formation and heating, 3) development of additional heating and non-inductive current drive methods in high-beta plasmas, 4) magnetic reconnection physics in laboratory and solar plasmas. Our research group has been developing the fundamental theories of computer science and relevant techniques of computer graphics. The research themes include simulation and realistic rendering of complex natural phenomena and lighting effects, hardware-assisited computations of such complex phenomena and their applications to interactive systems, and non-photoreaslitic rendering by simulating the complex processes of artistic drawing and painting. Furthermore, the representation and visualization of complex structures and phenomena, and optimal viewpoint location and its application to non-perspective projection techniques that match with the human visual cognition have also been studied. Associate Professor: Michiaki Inomoto Professor: Tomoyuki Nishita Associate Professor: Shigeo Takahashi Strongly Correlated Systems Complexity and Active Intelligence We are studying the electronic structures of complex materials and strongly correlated systems using photoemission, inverse-photoemission and x-ray absorption spectroscopies and subsequent analyses using various models. We research focus is made on high-temperature superconductivity, giant magneto-resistance, metal-insulator transition, charge and orbital ordering, non-Fermi-liquid behaviors, etc. The activity of our group emphasizes control aspects of complex systems.Currently, our focus is on the interplay between biology and control theory.Control is very fundamental in every aspect of living existence ranging from cell homeostasis to intelligent movements of individuals, from colon bacillus to mammalians. It may be regarded as an essential way of representing life phenomena. We would like to find a universal principle of control in biology which has been evolving throughout the whole history of living creatures. We are now investigating the two themes of biological control bearing the above ambitious goals in mind. The one is to find an essential architecture of calcium homeostasis in yeast and the other is the algorithm of brain motor control for biped locomotions of human being. Through these seemingly uncorrelated two subjects, we are trying to find an essential and universal principle of biological control. As the research goes, we are finding that both control problems are very complex, actually overwhelmingly complex. It is our mission trying to circumvent the increasingly complex pictures of living existence that are mainly brought by the recent rapid advance of molecular biology. Associate Professor: Takashi Mizokawa Professor: Masato Okada Surface and Materials Science Biological Complex Systems We are studying the electronic structures of complex materials and strongly correlated systems using photoemission, inverse- photoemission and x-ray absorption spectroscopies and subsequent analyses using various models. Our on-going research projects are related to high-Tc superconductivity, photo-induced phase transition, multiferroics etc. Our laboratory studies higher brain functions of humans. We measure and analyze the brain's characteristics and make mathematical models and artificial brains. We use very advanced and sophisticated magnetoencephalography (MEG) to measure magnetic fields emitted from the brain and three-dimensional optometry (TDO) to measure three basic ocular functions (eye movement, accommodation and pupil response). The MEG is the only system in the world used for education. From the data, various brain and visual models have been developed to elucidate human information processes in the brain. Our laboratory also researches the inverse problem and the visualization of the MEG data. Professor: Koichiro Saiki Associate Professor: Takehiko Sasaki Professor: Tsunehiro Takeda Associate Professor: Ayumu Matani Earth and Planetary Science Physics of Complex Phenomena The evolution of the earth and planetary interiors is controlled by interactive processes between different hierarchies of spatial and temporal scales, such as those between diffusion and reaction processes of an atomic scale and the global dynamics of the mantle convection. The purpose of our group is to extract the essence of these processes and to clarify their fundamental relationship. What are the basic physical mechanisms of brain formation? The goal of our laboratory is to elucidate the molecular mechanism of neural development and function using the simple nervous system of the fruit fly, Drosophila, as a model. 1) Identification of molecular cues that determines synaptic target specificity. The proper functioning of the nervous system depends on precise interconnections of distinct types of neurons. Therefore, elucidating the mechanism of how neurons find and recognize their target cells is an important goal in neuroscience. We identified molecular cues that are expressed on specific target cells and that determine the synaptic specificity. 2) In vivo imaging of synapse formation By using high-resolution live-imaging, we succeeded in observing the processes of synapse formation in real time in the intact organism. We investigated the dynamics of molecular assembly and signal transduction at the onset of synapse formation. 3) Molecular mechanisms of synaptic maturation Synapses change their properties even after their initial formation in response to changes in neural activity. At the neuromuscular junction in Drosophila, synapses grow in response to changes in the muscle volume and larval activity, to maintain and/or adjust synaptic transmission. We use this system as a model to study the mechanism of activity-dependent synaptic change. Professor: Mitsuhiro Toriumi Professor: Akinao Nose Complex Nonlinear Science Cooperative Faculty Members The ultimate purpose of the study of the earth and planetary evolution is to reveal when and how their material-sphere differentiated and how the material and energy fluxes changed with time. Our group investigates the evolution of the earth and planetary from this point of view. The unique point of our group is that our interest covers not only the lithosphere, hydrosphere and atmosphere, but also the biosphere and humansphere. Professor: Tomoki Fukai (Brain Science Institute, RIKEN) Computational Neural Circuit Theory Associate Professor: Yasutaka Takata (Spring-8 Center, RIKEN) Synchrotron Radiation Materials Science Adjunct Faculty Members Professor: Yutaka Ueda (Institute of Solid State Physics, The University of Tokyo) Inorganic Solid State Chemistry Professor: Fujimori, Atsushi (Graduate School of Science, The University of Tokyo) Photoemission spectroscopy, Strongly correlated/complex materials Professor: Kiyoshi Takano (Interfaculty Initiative in Information Studies, The University of Tokyo) Computer Networking Seismology Professor: Seiji Sugita Associate Professor: Hideaki Miyamoto (The University Museum, The University of Tokyo) Planetary geology, Volcanology, Planetary exploration