Detecting non-magnetic excitations in quantum magnets

TL;DR

This paper explores experimental methods to detect non-magnetic excitations like photons and visons in quantum magnets, using phonon spectral features and charge density fluctuations as signatures.

Contribution

It proposes two novel experimental approaches for identifying non-magnetic excitations in quantum magnets, enhancing detection capabilities for unconventional quantum phases.

Findings

Phonon spectral functions reveal features indicating non-magnetic excitations.

Charge density fluctuations can be detected via Terahertz spectroscopy.

Observation of singlet excitations confirms unconventional quantum phases.

Abstract

Many unconventional quantum phases host special non-magnetic excitations such as photons and visons. We discuss two possible ways to detect these excitations experimentally. Firstly, spin-lattice coupling mixes the excitations with phonons. The phonon spectral function acquires new features that can be detected by neutron or X-ray scattering. Secondly, valence-bond fluctuations translate into charge density fluctuations on non-bipartite lattices. Such charge fluctuations can be characterized by conventional spectroscopies such as Terahertz spectroscopy. Observation of exotic singlet excitations would provide positive identification of unconventional quantum phases in frustrated antiferromagnets.