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

Abstract

The finite-size scaling function of the nonlinearsusceptibility of the ferromagnetic Heisenberg chain is givenexplicitly. It is conjectured that the scaling function is universalfor any values of S. The conjecture is based on the exact solution ofthe nonlinear susceptibility for S=∞, and numerical calculationsfor S=1/2 and S=1.