A Quantum Network Node Based on the Silicon-Vacancy Defect in Diamond

Abstract

Entangling spatially separated quantum bits is an important tool for quantum key distribution, quantum sensing, and scalable quantum computing. The negatively charged silicon-vacancy center in diamond (SiV) is unique in its potential for efficient, high-fidelity gates with optical photons, which is the prerequisite for entangling networks of separated quantum bits. We have recently implemented a scheme to entangle SiVs with different optical transition frequencies, overcoming the inhomogeneous distribution common in solid-state optical qubits. Additionally, we have engineered high fidelity gates between the SiV spin and the spin of the $^{29}$Si nucleus, which can serve as a long-lasting quantum memory. These two advances present the prospects for entanglement distillation, device-independent quantum key distribution and distributed quantum sensing.