Small parameter for lattice models with strong interaction

TL;DR

This paper introduces a renormalization method for lattice models with localized nonlinearity, improving convergence and applicability to strongly correlated systems, demonstrated through benchmark results on classical O(N) models.

Contribution

It develops a diagram series renormalization technique that converges in both tight and weak binding regimes for strongly correlated lattice models.

Findings

Renormalized series converges well in strong and weak binding cases.

Benchmark results for classical O(N) models on cubic lattices.

Method effectively describes strongly correlated localized interactions.

Abstract

Diagram series expansion for lattice models with a localized nonlinearity can be renormalized so that diagram vertexes become irreducible vertex parts of certain impurity model. Thus renormalized series converges well in the very opposite cases of tight and weak binding and pretends to describe in a regular way strong-correlated systems with localized interaction. Benchmark results for the classical O(N) models on a cubic lattice are presented.