Huijse, L. and Mehta, D. and Moran, N. and Schoutens, K. and Vala, Jiri (2012) Supersymmetric lattice fermions on the triangular lattice: superfrustration and criticality. New Journal of Physics , 14 (073002). pp. 2-41. ISSN 1367-2630

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Abstract

We study a model for itinerant, strongly interacting fermions where a judicious tuning of the interactions leads to a supersymmetric Hamiltonian. On the triangular lattice this model is known to exhibit a property called superfrustration, which is characterized by an extensive ground state entropy. Using a combination of numerical and analytical methods we study various ladder geometries obtained by imposing doubly periodic boundary conditions on the triangular lattice. We compare our results to various bounds on the ground state degeneracy obtained in the literature. For all systems we find that the number of ground states grows exponentially with system size. For two of the models that we study we obtain the exact number of ground states by solving the cohomology problem. For one of these, we find that via a sequence of mappings the entire spectrum can be understood. It exhibits a gapped phase at 1/4 filling and a gapless phase at 1/6 filling and phase separation at intermediate fillings. The gapless phase separates into an exponential number of sectors, where the continuum limit of each sector is described by a superconformal field theory.

Item Type:	Article
Additional Information:	This article is available at L Huijse et al 2012 New J. Phys. 14 073002 doi:10.1088/1367-2630/14/7/073002
Keywords:	Supersymmetric; lattice fermions; triangular lattice; superfrustration; criticality;
Academic Unit:	Faculty of Science and Engineering > Mathematical Physics
Item ID:	4494
Depositing User:	Dr. Jiri Vala
Date Deposited:	16 Sep 2013 15:45
Journal or Publication Title:	New Journal of Physics
Publisher:	Institute of Physics (IoP) and Deutsche Physikalische Gesellschaft
Refereed:	Yes
URI:	http://iopscience.iop.org/1367-2630
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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