Fall 2015
Colloquia are held on Fridays at 11:30 a.m. in Cullimore Lecture Hall II, unless noted otherwise. Refreshments are served at 11:30 am. For questions about the seminar schedule, please contact Yassine Boubendir.
Date: October 9, 2015
Speaker: Carlos Garcia-Cervera
Department of Mathematics,
University of California, Santa Barbara
Title: "Undulations in Smectic A Liquid Crystals"
Abstract:
We study de Gennes and Chen-Lubensky free energies for smectic A liquid crystals over S^2 valued vector fields to understand the chevron (zigzag) pattern formed in the presence of an applied magnetic field. As the applied field increases well above the critical field, the sinusoidal shape of the smectic layer at the onset of undulation will change into the chevron patterns with a longer period. We consider a square domain to represent the cross section of a three dimensional smectic A liquid crystal sample. Well above the instability threshold, we show via Gamma-convergence that a chevron structure where the director connects two minimum states of the sphere is favored. Numerical simulations illustrating the chevron structures for both models will be presented.
This is a joint work with T. Giorgi and S. Joo.