Decoupling approximation in spin- Ising systems

Enaldo F. Sarmento, I. Tamura, T. Kaneyoshi

P.W. Kasteleijn

Yasuko Inaba, Giiti Iwata

Yoshiaki Tanaka, Norikiyo Uryû

With the use of a rigorous relation of the correlations in the Ising spin system, an approach to the exact magnetic susceptibility of the two-dimensional Ising antiferromagnet has been attempted. The zero-field magnetic susceptibilities for the rectangular as well as the square antiferromagnets are shown to be expressed in terms of finite near-spin correlations. With some decoupling approximations for many-spin correlations, the result for the square antiferromagnet by the present method is proved to be within 0.35% from that of the series expansion.

Hadey K. Mohamad

Zhu Jian-Yang, Yang Zhan-Ru

A single-spin transition critical dynamics is used to investigate the three-dimensional kinetic Ising model on an anisotropic cubic lattice. We first derive the fundamental dynamical equations, and then linearize them by a cutoff approximation. We obtain the approximate solutions of the local magnetization and equal-time pair correlation function in zero field. In which the axial-decoupling terms , and as higher infinitesimal quantity are ignored, where . We think that it is reasonable as the temperature of the system is very high. The result of what we obtain in this paper can go back to the one-dimensional Glauber's theory as long as .