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Home | Seminars and Symposia | Past seminars/symposia: Thursday, December 12, 2002

DTC Seminar Series

by

Tetsuo Deguchi

Department of Physics

Ochanomizu University

Thursday, December 12, 2002

2:00 pm

402 Walter Library

In polymer physics, it is still a nontrivial question of how some physical properties of polymers are dependent on their topology. Making use of knot invariants introduced recently, several topological properties of ring polymers can be explicitly studied through simulations of self-avoiding polygons (SAPs). In this talk, Dr. Deguchi will show that SAPs with a fixed knot (which we call random knots) are larger in size than those of no topological constraint when the number of polygonal nodes is large enough. The effective swelling may be due to topological entropic repulsion and it is particularly significant when the excluded volume is small.

Dr. Tetsuo Deguchi received the B.S and M.S. degrees from the University of Tokyo, Department of Physics, Tokyo, Japan and received a Ph.D. degree in Physics from the University of Tokyo in 1992. He was an Assistant Professor with the Department of Physics from 1990 to 1993 at the University of Tokyo and in 1994 joined the Department of Physics at the Ochanomizu University in Tokyo, Japan. Dr. Deguchi was an Associate Professor from 1994 to 2000 and has been a Professor since 2001. He was a visiting scientist at the Institute of Theoretical Physics at the State University of New York at Stony Brook from 1997 to 1998. His focus of interest is in mathematical physics, polymer physics, and statistical physics in general. Dr. Deguchi studied mathematical physics related to knot theory, in particular, on exactly solvable models in statistical mechanics, topological invariants of knots and links, and qunantum groups during 1987 through 1993. Since 1994, he has been mainly studying numerical applications of knot invariants to statistical physics of polymers, for instance, some topics related to random knotting and linking, and topolgoical properties of ring polymers. His more recent interest includes other branches of polymer physics such as polymer gels and polymer crystallization. In mathematical physics, his current research subject is on the spectral degeneracy of the XXZ and XYZ spin chains at roots of unity through the algebraic Bethe ansatz (the Quantum Inverse Scattering Method) and elliptic quantum groups.