Propagation and Ghosts in the Classical Kagome Antiferromagnet

TL;DR

This paper explores the classical spin dynamics of the kagome antiferromagnet, revealing two low-temperature regimes with propagative modes, gauge invariance effects, and the presence of ghost excitations with reduced spectral weight.

Contribution

It provides a detailed analysis of excitations, identifying ghosts and gauge invariance effects in the dynamical behavior of the kagome antiferromagnet.

Findings

Two distinct low-temperature dynamical regimes with propagative modes

Identification of ghosts with reduced spectral weight in the structure factor

Evidence of gauge invariance in low-energy excitations

Abstract

We investigate the classical spin dynamics of the kagome antiferromagnet by combining Monte Carlo and spin dynamics simulations. We show that this model has two distinct low temperature dynamical regimes, both sustaining propagative modes. The expected gauge invariance type of the low energy low temperature out of plane excitations is also evidenced in the non linear regime. A detailed analysis of the excitations allows to identify ghosts in the dynamical structure factor, i.e propagating excitations with a strongly reduced spectral weight. We argue that these dynamical extinction rules are of geometrical origin.