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TT: Fachverband Tiefe Temperaturen

TT 24: Correlated Electrons: Low-dimensional Systems - Models

TT 24.2: Vortrag

Mittwoch, 27. Februar 2008, 14:15–14:30, H 2053

Emergent fermions and anyons in the Kitaev model — •Kai P. Schmidt¹, Sebastien Dusuel², and Julien Vidal³ — ¹Institute of Theoretical Physics, Ecole Polytechnique Federal de Lausanne, CH-1015 Lausanne, Switzerland — ²Lycee Louis Thuillier, 70 Boulevard de Saint Quentin, 80098 Amiens Cedex 3, France — ³Laboratoire de Physique Theorique de la Matiere Condensee, CNRS UMR 7600,

We study the gapped phase of the Kitaev model on the honeycomb lattice using perturbative continuous unitary transformations. The effective low-energy Hamiltonian is found to be an extended toric code with interacting anyons. High-energy excitations are emerging free fermions which are composed of hardcore bosons with an attached string of spin operators. The excitation spectrum is mapped onto that of a single particle hopping on a square lattice in a magnetic field. The present approach yields analytical perturbative results in the thermodynamical limit and gives a simple description of the spectrum without using the Majorana or the Jordan-Wigner fermionization initially proposed to solve this problem.