Path integral spin dynamics for quantum paramagnets

TL;DR

This paper introduces a path integral approach combined with atomistic spin dynamics to compute thermal quantum expectation values, effectively handling non-linear Hamiltonian terms relevant for uniaxial anisotropies.

Contribution

It develops a novel method to treat non-linear Hamiltonians in quantum spin systems using a classical path integral framework.

Findings

Successfully incorporates non-linear terms in Hamiltonians

Enables classical simulation of quantum thermal averages

Applicable to systems with uniaxial anisotropies

Abstract

A path integral method, combined with atomistic spin dynamics simulations, has been developed to calculate thermal quantum expectation values using a classical approach. In this study, we show how to treat Hamiltonians with non-linear terms, that are relevant for describing uniaxial anisotropies and mechanical constraints. These interactions can be expressed solely through quadratic terms of the spin operator along one axis, that can be identified with the quantisation axis.