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Randall D. KAMIEN

Smectic liquid crystals : the Soft Superconductor ?

Résumé :
Nearly 40 years ago, in this building, de Gennes proposed a beautiful analogy between superconductors and a phase of matter consisting of parallel layers of molecules in space : the smectic liquid crystal. This analogy allows us to simultaneously understand the phases of both systems, and led, for instance, to the prediction and discovery of the TGB phase, the smectic analog of the Abrikosov flux line lattice. The precise mathematical analogy breaks down when the smectic crystal undergoes large distortions which necessitate the use of nonlinear elasticity. By recasting the problem of smectic configurations geometrically it is often possible to exploit toplogical information or, equivalently, boundary conditions, to confront these highly nonlinear problems.
I will discuss our recent work on edge dislocations, disclination networks in three- dimensionally modulated smectic crystals, and large angle twist grain boundary phases. Fortuitously, it is possible to make intimate comparison with experimental systems !



Biographie :
Randall Kamien is the Vicki and William Abrams Professor in the Natural Sciences at the University of Pennsylvania (Philadelphia, USA). He took his Ph.D. in 1992 working with David Nelson at Harvard. He spent three years as a member of the School of Natural Sciences at the Institute for Advanced Study (Princeton, USA) before moving to the University of Pennsylvania. He has served as an Associate Editor for Physical Review E and for Reviews of Modern Physics. His research interests include liquid crystals, topological defects, and materials geometry.


Contact : Randall D. Kamien
Vicki and William Abrams Professor in the Natural Sciences
Physics and Astronomy
University of Pennsylvania
Philadelphia kamien/