Quantum network with magnonic and mechanical nodes

Abstract

A quantum network consisting of magnonic and mechanical nodes connected by light is proposed. Recent years have witnessed a significant development in cavity magnonics based on collective spin excitations in ferrimagnetic crystals, such as yttrium iron garnet (YIG). Magnonic systems are considered to be a promising building block for a future quantum network. However, a major limitation of the system is that the coherence time of the magnon excitations is limited by their intrinsic loss (typically in the order of 1 µs for YIG). Here, we show that by coupling the magnonic system to a mechanical system using optical pulses, an arbitrary magnonic state (either classical or quantum) can be transferred to and stored in a distant long-lived mechanical resonator. The fidelity depends on the pulse parameters and the transmission loss. We further show that the magnonic and mechanical nodes can be prepared in a macroscopic entangled state. These demonstrate the quantum state transfer and entanglement distribution in such a novel quantum network of magnonic and mechanical nodes.Our work shows the possibility to connect two separate fields of optomagnonics and optomechanics, and to build a long-distance quantum network based on magnonic and mechanical systems.

High-fidelity topological quantum state transfers in a cavity–magnon system

“…On the other hand, cavity optomagnonic systems have been extensively investigated recently, which provide a new platform for studying quantum effect. [46][47][48][49][50][51][52][53][54][55][56] Magnon, the collective spin excitation for ferromagnetic material, can realize the strong (even ultrastrong) couplings with cavity photons. [46,51] Further, the yttrium iron garnet (YIG) sphere is often used as the ferromagnetic material for the experiment, and this has been characterized by high collective spin excitation density and low dissipation.…”

“…[59,60] Moreover, compared to cavityoptomechanical systems, the cavity optomagnonic system possesses a long coherence time and intrinsically good tunability. [46] Based on the merits of the cavity optomagnonic system, it is also expected to implement the potential application in quantum information networks, [55] quantum sensing, [61,62] and magnon dark modes in magnon-gradient memories. [63] In this study, in terms of these excellent properties of cavity-magnon systems, a new protocol for implementing high-fidelity QST is proposed.…”

Topological state transfers in cavity-magnon system

“…On the other hand, cavity optomagnonic systems have been extensively investigated recently, which provide a new platform for studying quantum effect [47][48][49][50][51][52][53][54][55][56]. Magnon, the collective spin excitation for ferromagnetic material, can realize the strong (even ultrastrong) couplings with cavity photons [47].…”

“…Moreover, compared to cavity-optomechanical systems, the cavity optomagnonic system possesses a long coherence time and intrinsically good tunability [47]. Based on the merits of the cavity optomagnonic system, it is also expected to implement the potential application in quantum information networks [56], quantum sensing [61,62] and magnon dark modes in magnon-gradient memory [63].…”