Electrically controlled entanglement of cavity photons with electromagnons

Electromagnonics is an emerging field with a focus on entangling magnonic excitations to the microwave cavity photon modes with the prospect for use in quantum information science. Here, we discuss a class of Hamiltonians that embody a substantial steady-state photon-magnon entanglement enabled by a chiral coupling of the magnonic system to the cavity electric field. It is demonstrated how the entanglement can be controlled via external parameters. As a realization, we study a layered system that hosts an interfacial Dzyaloshinskii-Moriya interaction whose strength varies linearly with the cavity electric field rendering the low-energy spin excitations susceptible to an electric field and resulting in nonlinear magnon-photon dynamics. Accounting for interactions with the environment, we derive from the stochastic quantum Langevin equations explicit expressions evidencing the existence of a finite, steady-state entanglement and detailing its dependencies on external probes. The results point to particular types of electromagnonic systems that are potentially useful for quantum information applications.

Automated summary

Electromagnonics is an emerging field focusing on entangling magnonic excitations with microwave cavity photon modes for quantum information science. This study discusses a class of Hamiltonians that enable steady-state photon-magnon entanglement via a chiral coupling of the magnonic system to the cavity electric field. The entanglement can be controlled by external parameters. A layered system with varying interfacial Dzyaloshinskii-Moriya interaction is studied as a realization, demonstrating nonlinear magnon-photon dynamics. The derived expressions from stochastic quantum Langevin equations indicate the existence of steady-state entanglement and its dependencies on external probes, suggesting potential applications in quantum information.