Seminar tomorrow

[CM ICTP - Trieste]

JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR




Wednesday, 7 May    -    12:30 hrs.



Lecture Room 'D' - SISSA Main Building



C.J. SCHOUTENS   ( University of Amsterdam )


" Superfrustration of lattice fermions "




Abstract

The term superfrustration refers to massive ground state degeneracy in 
supersymmetric lattice models for itinerant fermions with strong 
repulsive interactions, in dimension D>1.  In general, quantum phases 
of lattice fermions are hard to track, due to lack of analytic methods 
and fundamental difficulties in numerical analysis.  I will show how 
supersymmetry improves this situation and leads to exact results on the 
number and nature of quantum gound states.  Superfrustration is 
established by showing that on a variety of 2D lattices the 
supersymmetric model has extensive ground state entropy. For the 2D 
square lattice I demonstrate the existence of critical edge 
excitations.