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Systematic Inclusion of High-Order Multi-Spin Correlations for the Spin-$1\over2$ $XXZ$ Models

R. F. Bishop·R. G. Hale·Y. Xian
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Abstract

We apply the microscopic coupled-cluster method (CCM) to the spin-$1\over2$ $XXZ$ models on both the one-dimensional chain and the two-dimensional square lattice. Based on a systematic approximation scheme of the CCM developed by us previously, we carry out high-order {\it ab initio} calculations using computer-algebraic techniques. The ground-state properties of the models are obtained with high accuracy as functions of the anisotropy parameter. Furthermore, our CCM analysis enables us to study their quantum critical behavior in a systematic and unbiased manner.

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R. F. Bishop, R. G. Hale, Y. Xian. 1994-10-31. Systematic Inclusion of High-Order Multi-Spin Correlations for the Spin-$1\over2$ $XXZ$ Models. https://doi.org/10.1103/physrevlett.73.3157

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