The microscopic mechanism of phase transition may be the most attractive theme studied by statistical mechanics. The unified theory of phase transitions in equilibrium systems had been concluded by the renormalization group theory. After the success of this theory, some of researchers have aimed at (1) the research of unsolved mechanisms of characteristic phase transitions, but most of theoreticians in this field have been attracted to studies of phase transitions in (2) nonequilibrium systems or (3)random systems. The essential theoretical problem to be solved in these studies is how to renormalize effects of non-linear terms into thermodynamical quantities observed. (4) Researchers in these fields advanced into studies of non-linear dynamics. In non-linear problems, numerical computation and computer simulation play essential roles.The themes in this laboratory cover those from (1) to (4) with close co-operations. (1) Studies of structural phase transitions such as ferroelectrics with close contacts with experimentalists working in the same campus. (2) Theoretical development of the path probability method proposed by Kikuchi, and the application of this method to the theory of crystal growth. (3) The theoretical study of spin glass, which is the mixed system between ferromagnets and antiferromagnets. Some concepts in this study are applied to understanding transmission mechanism of information in neural networks. (4) Non-linear dynamics is a new developing field common to mathematics. One of most interesting aims is the relation to biological phenomena. The themes from (2) to (4) in a wide sense, (4) in a narrow sense, are named "study of complexity".
Staffs Masaharu TOKUNAGA(Prof.) tokunaga@phys.hokudai.ac.jp 706-5273 Koh WADA(Prof.) kwada@phys.hokudai.ac.jp 706-3517 Koji NEMOTO(Associate Prof.) nemoto@phys.hokudai.ac.jp 706-3441 Koji OKUDA(Instructor) okuda@phys.hokudai.ac.jp 706-3442 Students Hirokazu OHMI(D2) h_omi@phys.hokudai.ac.jp 706-3443 Yoshito KATANO(M2) katano@phys.hokudai.ac.jp 706-3443 Yuki KABASAWA(M2) kabasan@phys.hokudai.ac.jp 706-3443 Sadanori YAMADA(M2) yamada@phys.hokudai.ac.jp 706-3443 Yoshihiro OGAWA(M1) ogawa@phys.hokudai.ac.jp 706-3443 Munetaka SASAKI(M1) msasaki@phys.hokudai.ac.jp 706-3443 Takashi YOSHIDA(M1) yoshidat@phys.hokudai.ac.jp 706-3443 Naomi INOHARA(B4) inohara@phys.hokudai.ac.jp 706-3443 Norihiro IHARA(B4) ihara@phys.hokudai.ac.jp 706-3443 Mitsutaro TANAKA(B4) mitsuta@phys.hokudai.ac.jp 706-3443