Controlling the magnon-photon interface via a cavity Fano resonance

The interface between photons and magnons has introduced the opportunity to perform quantum information processing in macroscopic systems. So far, strong coupling and Rabi oscillations have been exploited to control the coupling between photons and magnons in microwave cavities (1–3). Here, we present a new scheme to achieve spectral control of magnon-photon coupling via Fano interference. The Fano resonance is controlled via cavity detuning, which acts as the background channel in the Fano picture at low coupling. An incoherent term in the Fano picture, normally attributed to decoherence in open quantum systems (4), actually arises here due to the coupling of a discrete matter resonance with a resonant cavity mode. Magnon-photon hybridization at higher coupling strengths effects the breakdown of the Fano picture. These results establish spectral Fano control in cavity electromagnonics, which may lead to advances in room temperature quantum information processing.
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