Central limit theorem for exponentially quasi-local statistics of spin models on Cayley graphs

TL;DR

This paper establishes central limit theorems for local and exponentially quasi-local statistics of spin models on Cayley graphs, extending results to models with weaker mixing conditions and diverse applications.

Contribution

It proves general CLTs for spin models on Cayley graphs under weaker mixing assumptions and introduces new results for exponentially quasi-local statistics.

Findings

CLTs hold for various spin models with polynomial growth Cayley graphs.

Results apply to models with fast decaying covariances like Ising and Gaussian free fields.

Includes applications to computational topology, statistical physics, and random networks.

Abstract

Central limit theorems for linear statistics of lattice random fields (including spin models) are usually proven under suitable mixing conditions or quasi-associativity. Many interesting examples of spin models do not satisfy mixing conditions, and on the other hand, it does not seem easy to show central limit theorem for local statistics via quasi-associativity. In this work, we prove general central limit theorems for local statistics and exponentially quasi-local statistics of spin models on discrete Cayley graphs with polynomial growth. Further, we supplement these results by proving similar central limit theorems for random fields on discrete Cayley graphs and taking values in a countable space but under the stronger assumptions of {\alpha}-mixing (for local statistics) and exponential {\alpha}-mixing (for exponentially quasi-local statistics). All our central limit theorems assume a suitable variance lower bound like many others in the literature. We illustrate our general central limit theorem with specific examples of lattice spin models and statistics arising in computational topology, statistical physics and random networks. Examples of clustering spin models include quasi-associated spin models with fast decaying covariances like the off-critical Ising model, level sets of Gaussian random fields with fast decaying covariances like the massive Gaussian free field and determinantal point processes with fast decaying kernels. Examples of local statistics include intrinsic volumes, face counts, component counts of random cubical complexes while exponentially quasi-local statistics include nearest neighbour distances in spin models and Betti numbers of sub-critical random cubical complexes.