University of Toronto
               PDE/Applied Math/Analysis Seminar
                 Friday March 17, 3:10-4pm
                       6183 Bahen Center      




SPEAKER:  Zoi Rapti (University of Illinois at Urbana-Champaign)



TITLE: Counting defect eigenvalues via the Evans function

ABSTRACT: We consider the problem of a Schroedinger equation
	with a potential consisting of a periodic part plus a compactly
	supported defect potential. We are studying the emergence of
	eigenvalues into the gaps of the essential spectrum, and in particular
	we are counting the number of such eigenvalues. We analyse the
	one-dimensional problem, for which an Evans function can be defined,
	whose zeros correspond to the eigenvalues in the gaps. Using a homotopy
	argument, we are then able to count the eigenvalues as they emerge.
	This is joint work with Jared Bronski.




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University of Toronto PDE/Applied Math/Analysis Seminar 
http://www.math.toronto.edu/appmath/

2005-2006 organizers:
          Pieter Blue           pblue@ math.toronto.edu
          Almut Burchard        almut@ math.toronto.edu
          Bob Jerrard           rjerrard@ math.toronto.edu
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