Exact solution of the $2d$ dimer model: Corner free energy, correlation functions and combinatorics

TL;DR

This paper provides an exact fermionic solution to the 2D dimer model on a square lattice, analyzing boundary effects, correlation functions, and combinatorial properties, thereby connecting discrete and scaling behaviors.

Contribution

It introduces a complete fermionic solution for the 2D dimer model with boundary monomers, including finite size effects and correlation functions, bridging combinatorics and field theory.

Findings

Exact correlation functions for monomers and dimers

Finite size analysis reveals corner and surface effects

Scaling dimensions consistent with bosonic predictions

Abstract

In this work, some classical results of the pfaffian theory of the dimer model based on the work of Kasteleyn, Fisher and Temperley are introduced in a fermionic framework. Then we shall detail the bosonic formulation of the model {\it via} the so-called height mapping and the nature of boundary conditions is unravelled. The complete and detailed fermionic solution of the dimer model on the square lattice with an arbitrary number of monomers is presented, and finite size effect analysis is performed to study surface and corner effects, leading to the extrapolation of the central charge of the model. The solution allows for exact calculations of monomer and dimer correlation functions in the discrete level and the scaling behavior can be inferred in order to find the set of scaling dimensions and compare to the bosonic theory which predict particular features concerning corner behaviors. Finally, some combinatorial and numerical properties of partition functions with boundary monomers are discussed, proved and checked with enumeration algorithms.