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VERSION:2.0
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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-2585
DTSTART:20120223T160000Z
DURATION:PT1H0M0S
DTSTAMP:20260420T062122Z
LAST-MODIFIED:20120127T171350Z
LOCATION:5310 Chamberlin
SUMMARY:Seeing and Sculpting Nematic Liquid Crystal Textures with the 
 Thom construction\, R. G. Herb Condensed Matter Seminar\, Bryan Chen\,
  University of Pennsylvania
DESCRIPTION:Nematic liquid crystals are the foundation for modern disp
 lay technology and also exhibit topological defects that can readily b
 e seen under a microscope.  Recently\, experimentalists have been able
  to create and control more and more interesting defect textures\, inc
 luding controllably knotted defect lines around colloids (Ljubljana) a
 nd the "toron"\, a pair of hedgehogs bound together with a ring of dou
 ble-twist between them (CU Boulder).  I will discuss recent work with 
 Gareth Alexander (Warwick) applying the Thom construction from algebra
 ic topology which allows us to visualize 3 dimensional molecular orien
 tation fields as certain colored surfaces in the sample.  These surfac
 es turn out to be a generalization to 3 dimensions of the dark brushes
  seen in Schlieren textures of two-dimensional samples of nematics.  M
 anipulations of these surfaces correspond to deformations of the nemat
 ic orientation fields\, giving a hands-on way to classify liquid cryst
 al textures which is also easily computable from data and robust to no
 ise. 
URL:https://www.physics.wisc.edu/events/?id=2585
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