Essentially all substances that we experience through our sensory organs are many-particle systems consisting of a large number of constituent particles, say, atoms or molecules. In particular, a strongly interacting many-particle system, called condensed matter, may display collective properties as characteristics of the whole system. Such properties may not be reduced to the properties of individual constituent particles; they emerge as a result of the cooperative phenomena between constituent particles. To understand condensed matter, we thus need to move from the microscopic description to the macroscopic description, which is provided by statistical mechanics appropriate for describing many-particle systems. Whereas condensed matter physics is named according to the research object, the research method, i.e., statistical mechanics, is emphasized in the term of statistical physics. Namely, statistical physics stands for the field of physics, which attempts to understand, by means of statistical mechanics, properties of very diverse many-particle systems as well as condensed matter.
In this century there is emerging diversity of new specialized fields while the traditional barrier of the discipline is melting down. If the 20th century was characterized by the success story of the traditional physics, the main contribution of physics in this century is likely to be applications of the methodology or paradigm of physics to understand diverse phenomena of many new emerging disciplines. Accordingly, physics is expected to expand its horizon enormously to accomodate diverse fields beyond the traditional realm and statistical physics in particular to play a leading role in this venue. In statistical mechanics entropy, closely related with information of the many-particle system, connects the microscopic and macroscopic states and plays the key role in the time evolution from nonequilibrium states toward equilibrium ones. Statistical physics, which may be regarded as the science of entropy or information, has extremely diverse research topics since most of the phenomena we observe result from properties of many-particle systems, particularly in nonequilibrium. In addition, many generic systems in nature exhibit complexity, characterized by large variability, in the border of order and disorder. Understanding such complex systems, usually possessing frustration together with randomness, offers a challenge in this century. This may also be relevant to the micro-structure of many electron systems and/or superconducting systems, where quantum coherence is maintained, and is thus important in mesoscopic systems and strongly correlated systems, which provide the basis for nano-technology.
The statistical physics and condensed matter theory group conducts research into cooperative phenomena and diverse properties of condensed matter systems. Main topics investigated recently include nonequilibrium phenomena in reaction diffusion systems, absorbing phase transitions and self-organized criticality, dynamic behaviors of complex systems and biological systems, and transport properties and quantum phase transitions in low-dimensional mesoscopic and/or strongly correlated systems.