Critical temperature and the transition from quantum to classical order parameter fluctuations in the three-dimensional Heisenberg antiferromagnet

TL;DR

This paper uses quantum Monte Carlo simulations to determine the critical temperature of a 3D Heisenberg antiferromagnet and explores the transition from quantum to classical order parameter fluctuations at the phase transition.

Contribution

It provides precise numerical estimates of the critical temperature and analyzes the nature of the quantum-to-classical transition in a 3D antiferromagnetic system.

Findings

Critical temperature Tc/J = 0.946 +/- 0.001

Transition behavior aligns with classical 3D Heisenberg universality

Discussion of quantum to classical fluctuation transition

Abstract

We present results of extensive quantum Monte Carlo simulations of the three-dimensional (3D) S=1/2 Heisenberg antiferromagnet. Finite-size scaling of the spin stiffness and the sublattice magnetization gives the critical temperature Tc/J = 0.946 +/- 0.001. The critical behavior is consistent with the classical 3D Heisenberg universality class, as expected. We discuss the general nature of the transition from quantum mechanical to classical (thermal) order parameter fluctuations at a continuous Tc > 0 phase transition.