Universal Finite-Size Scaling Function of the Ferromagnetic Heisenberg Chain in a Magnetic Field. II

TL;DR

This paper presents an explicit finite-size scaling function for the nonlinear susceptibility of the ferromagnetic Heisenberg chain, proposing its universality across different spin values based on exact and numerical results.

Contribution

It introduces a conjecture that the finite-size scaling function is universal for all spin values, supported by exact and numerical analyses.

Findings

Explicit finite-size scaling function derived

Conjecture of universality across spin values

Numerical validation for S=1/2 and S=1

Abstract

The finite-size scaling function of the nonlinear susceptibility of the ferromagnetic Heisenberg chain is given explicitly. It is conjectured that the scaling function is universal for any values of $S$. The conjecture is based on the exact solution of the nonlinear susceptibility for $S=\infty$, and numerical calculations for $S=1/2$ and $S=1$.