Quantum Institute: Visitor Schedule

The Quantum Lunch is regularly held on Thursdays in the Theoretical Division Conference Room, TA-3, Building 123, Room 121.
For more information, contact Diego Dalvit.

December 18, 2008
Thursday, 12:30 PM to 2 PM

Speaker: Ilya Gruzberg, University of Chicago

Technical Host: Razvan Teodorescu

TOPIC: Critical wave functions, conformal invariance, and theories for quantum Hall transitions

Abstract

Wave functions at Anderson localization-delocalization (LD) transitions are known to exhibit complicated scale-invariant behavior best characterized by an infinite set of multifractal exponents. I will present our recent study of multifractal spectra of critical wave functions at various Anderson transitions, focusing on finite systems with boundaries. In two dimensions the boundary behavior of the critical wave functions provides a way to answer the question of conformal invariance at these transitions. For the integer quantum Hall transition the multifractal spectra were conjectured to be exactly parabolic in a number of proposals of critical field theories for the transition. Our numerical results for the Chalker-Coddington network model firmly rule out the exact parabolicity.