Berlin 2012 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 1: Correlated Electrons: Low-dimensional Systems - Models 1

TT 1.12: Vortrag

Montag, 26. März 2012, 12:30–12:45, H 0104

Robustness of a Z(3) topological phase — •Marc Daniel Schulz^1,4, Sébastien Dusuel², Roman Orùs³, Julien Vidal⁴, and Kai Phillip Schmidt¹ — ¹Lehrstuhl für Theoretische Physik I, Technische Universität Dortmund, Otto-Hahn-Straße 4, 44221 Dortmund, Germany — ²Lycée Saint-Louis, 44 Boulevard Saint-Michel, 75006 Paris, France — ³Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany — ⁴Laboratoire de Physique Théorique de la Matière Condensée, CNRS UMR 7600, Université Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris Cedex 05, France

Kitaev's toric code model is an exactly solvable lattice model, whose ground state(s) are topologically ordered. We study the robustness of a generalized version of this model with Z(N) degrees of freedom in the presence of local perturbations. For N = 2, this model reduces to the conventional toric code in a uniform magnetic field. A quantitative analysis is performed for the perturbed Z(3) toric code by applying a combination of high-order series expansions and variational techniques. We provide strong evidences for first- and second-order phase transitions between topologically-ordered and polarized phases. Most interestingly, our results also indicate the existence of topological multi-critical points in the phase diagram.