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Cluster variation method and disorder varieties of two-dimensional Ising-like models

Alessandro Pelizzola
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Abstract

I show that the cluster variation method, long used as a powerful hierarchy of approximations for discrete (Ising-like) two-dimensional lattice models, yields exact results on the disorder varieties which appear when competitive interactions are put into these models. I consider, as an example, the plaquette approximation of the cluster variation method for the square lattice Ising model with nearest-neighbor, next-nearest-neighbor and plaquette interactions, and, after rederiving known results, report simple closed-form expressions for the pair and plaquette correlation functions.

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Alessandro Pelizzola. 2000-06-06. Cluster variation method and disorder varieties of two-dimensional Ising-like models. https://doi.org/10.1103/physrevb.61.11510

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