MONDAY, October 19
Condensed Matter Physics and Institute for Quantum Information Seminar, 4:00 PM - 5:00 PM, 107 Downs
"Quantum phases of a supersymmetric model of lattice fermions," Liza Huijse, University of Amsterdam. More info: CMP and IQI

Abstract:
We discuss recent results on frustration of quantum charges in lattice models for itinerant fermions with strong repulsive interactions. The models were introduced by P. Fendley and K. Schoutens. A judicious tuning of kinetic and potential terms leads to models possessing supersymmetry. In 1D this model is solved analytically and turns out to be quantum critical. The thermodynamic limit is described by an N=2 superconformal field theory. In 2D the model exhibits superfrustration: an extensive degeneracy of supersymmetric ground states. Using techniques from cohomology the ground state degeneracy can be obtained analytically. We demonstrate how for the 2D square lattice the ground state counting problem is fully solved through a remarkable correspondence with specific rhombus tilings of the plane.

Hosts: Matthew Fisher and John Preskill