High-precision estimate of g4 in the 2D Ising model

TL;DR

This paper accurately calculates the renormalized four-point coupling g4 in the 2D Ising model using transfer-matrix methods, significantly reducing systematic errors through precise scaling function knowledge.

Contribution

It introduces a method to precisely estimate g4 in the 2D Ising model by leveraging exact scaling function terms, improving accuracy over previous approaches.

Findings

Final estimate g4=14.69735(3)

Reduced systematic uncertainties in g4 calculation

Enhanced transfer-matrix computational techniques

Abstract

We compute the renormalized four-point coupling in the 2d Ising model using transfer-matrix techniques. We greatly reduce the systematic uncertainties which usually affect this type of calculations by using the exact knowledge of several terms in the scaling function of the free energy. Our final result is g4=14.69735(3).