  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.
