Cluster variational calculation for the magnetic ising model

Abstract

The cluster variation (CV)-method, developed by Strieb, Callen and Horwitz (SCH), has proved to be a useful tool to make calculations on lattice models involving hamiltonians with continuously varying interaction coordinates. In this article, the SCH-CV-method is employed to make calculations up to the four particle cluster approximation for the Ising model. Results for the critical temperature, the specific heat and its high temperature coefficients are obtained. They are compared with values obtained using the combinatorial CV-method as derived by Kikuchi (K-CV-method) and with results acquired from elaborate high-temperature expansions.

Additional information

Notes on contributors

R. van der Haegen

Aspirant Nationaal Fonds voor Wetenschappelijk Onderzoek, Belgium.

R. Luyckx

Aangesteld navorser Nationaal Fonds voor Wetensehappelijk Onderzoek, Belgium.