Magnon-driven dynamics of a hybrid system excited with ultrafast optical pulses

TL;DR

This paper demonstrates that magnon-based hybrid systems can detect spin wave quanta across a broad frequency range, with applications in searching for cosmological signals like cold Dark Matter.

Contribution

It introduces a model of a photon-magnon hybrid transducer capable of detecting spin waves driven by tiny magnetic fields, relevant for quantum sensing and cosmology.

Findings

Detection of spin wave quanta over a large frequency band

Model matches experimental observations

Potential application in large-scale ferromagnetic haloscopes

Abstract

The potential of photon-magnon hybrid systems as building blocks for quantum information science has been widely demonstrated, and it is still the focus of much research. We leverage the strengths of this unique heterogeneous physical system in the field of precision physics beyond the standard model, where the sensitivity to the so-called "invisibles" is currently being boosted by quantum technologies. Here, we demonstrate that quanta of spin waves, driven by tiniest, effective magnetic field, can be detected in a large frequency band using a hybrid system as transducer. This result can be applied to the search of cosmological signals related, for example, to cold Dark Matter, which may directly interact with magnons. Our model of the transducer is based on a second-quantisation two-oscillators hybrid system, it matches the observations, and can be easily extended to thoroughly describe future large-scale ferromagnetic haloscopes.