arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1004.3158math-phmath.GTmath.MP
收藏

一个推广的Kac-Ward公式

A generalized Kac-Ward formula

David Cimasoni

摘要:

Kac-Ward公式允许从大小为2N的矩阵的行列式计算具有直边的平面图G上的Ising配分函数,其中N表示G的边数。本文将这个公式推广到任何有限图:配分函数可以写成2^{2g}个大小为2N的矩阵的行列式的交替和,其中g是G嵌入的可定向曲面的亏格。我们给出了这个推广公式的两个证明。第一个是纯粹的组合,而第二个依赖于Fisher-Kasteleyn减少的伊辛模型的二聚体模型,和几何技术。作为第二个证明的结果,我们还得到了以下事实:求解伊辛模型的Kac-Ward方法和Fisher-Kasteleyn方法是同一个方法。

英文摘要:

The Kac-Ward formula allows to compute the Ising partition function on a planar graph G with straight edges from the determinant of a matrix of size 2N, where N denotes the number of edges of G. In this paper, we extend this formula to any finite graph: the partition function can be written as an alternating sum of the determinants of 2^{2g} matrices of size 2N, where g is the genus of an orientable surface in which G embeds. We give two proofs of this generalized formula. The first one is purely combinatorial, while the second relies on the Fisher-Kasteleyn reduction of the Ising model to the dimer model, and on geometric techniques. As a consequence of this second proof, we also obtain the following fact: the Kac-Ward and the Fisher-Kasteleyn methods to solve the Ising model are one and the same.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑