Two-dimensional quantum compass model in a staggered field: some rigorous results
Pei-Song He, Wen‐Long You, Guang-Shan Tian · Chinese Physics B · 2011
We study the properties of the two-dimensional quantum compass model in a staggered field. Using the Perron—Fröbenius theorem and the reflection positivity method, we rigorously determine the low energy spectrum of this model and its global ground state ψ 0 . Furthermore, we show that ψ 0 has a directional long-range order.