Communications in Theoretical Physics

The Critical Points of a Generalized Mixed Spin Model with Free Fermion Approximation

Fu-Gao Wang, Wen-yan Jia, Jia-Zhen Hu

Published Sep 15, 1994• 1 citation

Abstract

A generalized mixed spin model with anisotropic interactions is considered on the union jack lattice. We find that the model is equivalent to a free fermion model. The critical temperature is obtained. In special cases, we get the same results as exact solutions.

DOI: 10.1088/0253-6102/22/2/145

Related papers

CRITICAL TEMPERATURE CURVES FOR THE GENERALIZED MIXED SPIN MODEL

WANG FU-GAO, HU JIA-ZHEN, 上海交通大学应用物理系凝聚态物理研究所,上海200030

In this paper, we propose a generalized mixed spin model on the union jack lattice. The mean field. free-fermion approximations and equiscale transformation in the same universality class method are applied to this model. The critical temperature curves obtained by different methods agree with each other quite well. We also compare the three different methods. In some special cases, the same critical points as in exactly solved models are obtained.

Acta Physica SinicaJan 1, 19931 citation

Ising model on the union jack lattice as a free fermion model

Fa Yueh Wu, Ken‐Yu Lin

It is shown that the Ising model on the union jack lattice with general anisotropic and staggered interactions is equivalent to a free fermion model, and from this equivalence explicit expressions for its free energy and a sublattice spontaneous magnetisation are obtained.

Journal of Physics A Mathematical and GeneralNov 11, 198721 citations

The Critical Behavior of the Ising Model on Union Jack Lattice

Fu-Gao Wang, Jia-Zhen Hu

In this paper, we have investigated the critical behavior of the ferromagnetic Ising model on union jack lattice. The model is equivalent to the eight-vertex model which can be solved as a free fermion model with the free fermion approximation. The critical exponents have been obtained as and .

Communications in Theoretical PhysicsSep 15, 19960 citations

FREE-FERMION APPROXIMATE SOLUSION OF THE ISING MODEL ON UNION JACK LATTICE

WANG FU-GAO, HU JIA-ZHEN, 上海交通大学应用物理系凝聚态物理研究所,上海200030

In this paper,the Ising model with two-body anisotropic interactions and three-body interactions on union Jack lattice is solved by free-fermion approximation. We have obtained its free energy, spontaneous magnetisation and the equation of critical points. When the interaction coefficients are simplified as in a square lattice Ising model, the same solusion as Onsager's is obtained.

Acta Physica SinicaJan 1, 19930 citations

Three-spin correlation of the free-fermion model

Ken‐Yu Lin, Fa Yueh Wu

The authors consider the free-fermion model on the square lattice and obtain the local three-spin correlation function for three spins surrounding a unit cell of the lattice. As an application of this result, they compute the spontaneous magnetisation for the Ising model on the Union Jack lattice with the most general anisotropic interactions.

Journal of Physics A Mathematical and GeneralApr 21, 198913 citations

Critical couplings of mixed spin-1/2-spin-S Ising model: a free-fermion approximation

K -F Tang

A free-fermion approximation procedure is applied to the mixed spin-1/2-spin-S Ising models. The author's results for the critical coupling K c are in very satisfactory agreement with the high-temperature series results of Yousif and Bowers (1984).

Journal of Physics A Mathematical and GeneralNov 21, 198836 citations