Phonon networks with SiV centers in diamond waveguides

Electronic and nuclear spins associated with defects in solids comprise a promising platform for various quantum technologies. Prominent examples are NV and SiV centers in diamond, for which many techniques for coherent manipulations and local entanglement operations are already available. However, despite the impressive progress in the local control of spin qubits in diamond and other materials, the next big step of coherently integrating many spin qubits into larger networks has not been achieved yet. In this talk I will discuss a new approach to reach this goal by using quantized mechanical vibrations to mediate interactions between distant spin qubits. Specifically, I will describe the implementation of phonon quantum networks, where multiple SiV centers are coupled to propagating phonon modes in a quasi-1D diamond waveguide. In this setting, quantum states encoded in long-lived electronic spin states can be converted into travelling phonon wave packets and be reabsorbed by a distant defect center in a fully controllable way. I will show that under realistic experimental conditions, this technique enables the implementation of high-fidelity, scalable quantum communication protocols within chip-scale spin-qubit networks.

Reference: M.-A. Lemonde, S. Meesala, A. Sipahigil, M. J. A. Schuetz, M. D. Lukin, M. Loncar, and P. Rabl, Phys. Rev. Lett. 120, 213603 (2018)