一种推广伊辛自旋模型的实空间重正化群理论

本文提出了一种推广的伊辛自旋模型。它包括了伊辛自旋模型、Schofield和Bowers提出的混合自旋模型以及一种特殊的格点稀释伊辛自旋模型作为特例。运用实空间重正化群得到了这个推广模型的相变流图和三个非平庸不动点(一个伊辛不动点,一个三相不动点和一个一级相变不动点)。结果表明:混合自旋模型和伊辛模型属于同一普适类。证实了Schofield和Bowers通过直接对混合自旋模型临界指数的计算所做的结论。 关键词：

A GENERALIZED MIXED SPIN MODEL: A RENORMALISATION GROUP APPROACH

We propose a generalized Ising spin model, which contains the pure Ising model, the mixed spin model proposed by Schofield and Bowers and the particular site-diluted Ising spin model as special oases. A real space renormalisation group is applied to this model, the phase diagram is found to have three nontrivial fixed points (a Ising, a tric-ritical and a first order phase transition point). And it is demonstrated that mixed spin model and pure Ising spin model belong to the same universality, which is in agreement with the conclusion made by Schofield and Bowers who calculated the critical exponents of mixed model directly.