The stability of the topological order phase induced by the ${\mathbb{Z}}_3$ Kitaev model, which is a candidate for fault-tolerant quantum computation, against the local order phase induced by the three-state Potts model is studied. We show that the low-energy sector of the Kitaev-Potts model is mapped to the Potts model in the presence of transverse magnetic field. Our study relies on two high-order series expansions based on continuous unitary transformations in the limits of small and large Potts couplings as well as mean-field approximation. Our analysis reveals that the topological phase of the ${\mathbb{Z}}_3$ Kitaev model breaks down to the Potts model through a first-order phase transition. We capture the phase transition by analysis of the ground-state energy, one-quasiparticle gap, and geometric measure of entanglement.

• Received 20 March 2015
• Revised 18 May 2015

DOI:https://doi.org/10.1103/PhysRevB.91.245110