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Nature of the Quantum Phase Transition in Quantum Compass Model

Han-Dong Chen·Chen Fang·Jiangping Hu·Hong Yao
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Abstract

In this work, we show that the quantum compass model on an square lattice can be mapped to a fermionic model with local density interaction. We introduce a mean-field approximation where the most important fluctuations, those perpendicular to the ordering direction, are taken into account exactly. It is found that the quantum phase transition point at $J_x=J_z$ marks a first order phase transition. We also show that the mean field result is robust against the remaining fluctuation corrections up to the second order.

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Han-Dong Chen, Chen Fang, Jiangping Hu, Hong Yao. 2006-12-07. Nature of the Quantum Phase Transition in Quantum Compass Model. https://doi.org/10.1103/physrevb.75.144401

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