Fluctuating local field method probed for a description of small classical correlated lattices

TL;DR

This paper introduces a fluctuating local field method to better describe small classical correlated lattices, addressing limitations of standard approaches in capturing their collective fluctuations and single-site behavior.

Contribution

The authors propose a simple fluctuating local field approach that significantly improves the description of small classical lattices compared to traditional local field methods.

Findings

Enhanced accuracy in modeling small lattices with fluctuating local fields

Better representation of collective fluctuations and single-site degrees of freedom

Applicable to Ising and Heisenberg models under external fields

Abstract

Thermal-equilibrated finite classical lattices are considered as a minimal model of the systems showing an interplay between low energy collective fluctuations and single site degrees of freedom. Standard local field approach, as well as classical limit of the bosonic DMFT method, do not provide a satisfactory description of Ising and Heisenberg small lattices subjected to an external polarizing field. We show that a dramatic improvement can be achieved within a simple approach, in which the local field appears to be a fluctuating quantity related to the low energy degree(s) of freedom.