Universal Relaxation and Diffusion in Complex Interacting Systems

by Prof. K.L. Ngai (CNR-IPCF Associate, Dipartimento di Fisica, Univ. di Pisa)

Thursday 14 Apr 2011, 11:00 → 13:00 Europe/Rome

Aula Careri (Dip. di Fisica - Edificio G. Marconi)

Relaxation and diffusion in complex interacting systems including not just the glass-forming substances is necessarily a many-body problem because of intermolecular interactions and dynamic constraints. I shall present experimental data from diverse classes of complex interacting systems to show their dynamic properties are general. One interesting fact is that the dynamic properties of glassformers have striking exact analogues in interacting complex systems having nothing to do with glass transition. The existence of universal dynamic properties is perhaps not surprising if some fundamental physics governs many- body relaxation and diffusion and hence the properties should be universal. Moreover, the universal properties help us to bring out the basic or critical elements of the fundamental physics, which turn out to have been captured by my “Coupling Model” since 1979. Although many-body relaxation and diffusion in interacting systems is an unsolved problem and my “Coupling Model” can hardly be considered as a final solution, the critical elements identified and the universal dynamic properties discovered can guide some able colleagues to construct a satisfactory theory that is fully consistent with the plethora of experimental data, not only in the field of glass transition but also in other complex interacting systems.