LARGE DEVIATIONS PRINCIPLE FOR THE MEAN-FIELD HEISENBERG MODEL WITH EXTERNAL MAGNETIC FIELD

Abstract

In this paper, we consider the mean-field Heisenberg model with deterministic external magnetic field. We prove a large deviation principle for Sn=n
with respect to the associated Gibbs measure, where Sn=n is the scaled partial
sum of spins. In particular, we obtain an explicit expression for the rate function.