Hybrid Quantum Transduction Systems Based on Magnonic Materials

A recent breakthrough in quantum computation is based on cryocooled superconducting qubits with MW working frequencies. However, connecting quantum computers by high-fidelity and long-distance quantum networks requires optical photons. For that reason, many efforts are concentrated on research of Hybrid Quantum Systems (HQSs) to realize coherent quantum transduction between the MW and optical photons. This work presents the HQS concept based on the use of a highly concentrated spin material (that is a magnonic material) to realize quantum frequency conversion. Yttrium iron garnet (YIG) is one of the best candidate materials due to its low damping parameter and transparency at the optical telecommunication frequencies. Maximizing the conversion efficiency requires the development of approaches to realize a strong coupling between the subsystems of the magnon HQS. One of the possible approaches is the application of micro- and nano-sized YIG elements and MW/optical resonators. This work gives examples of prospective approaches to realize strongly coupled subsystems for constructing magnon-based HQSs. We have shown that Finite Element Method (FEM) modelling of the HQS subsystem, consisting of MW resonator and YIG crystal is a powerful tool for the analysis of the magnon-based HQSs on the provision that the YIG sizes are larger than the exchange length. The planar Fabry-Perot optical cavities based on Distributed Bragg Reflector (DBR) mirrors have been analyzed from the point of view of their miniaturization.