A spin-photon interface coupled to a local memory is a key component in brokered entanglement protocols for quantum communication and information processing. Group-IV color centers in diamond (SiV, GeV, and SnV) are promising candidates for this application, comprising an electronic spin with optical transitions acting as a spin-photon interface. However, the use of the intrinsic group-IV nuclear spin as a local memory for brokered entanglement remains an outstanding challenge, particularly for the heavier dopants, GeV and SnV, whose hyperfine features have not been extensively studied. Here, we present first-principles and experimental results characterising the hyperfine properties of the group-IV color centers. We discuss the effect of bias on the hyperfine levels, demonstrating a regime where the intrinsic nuclear spin can be used for brokered entanglement, and deriving expected coherence properties in this regime. We further demonstrate ground state spin control of a SnV-117 color center integrated in a photonic integrated circuit, showing 97.8% gate fidelity and 2.5 ms coherence time for the nuclear spin level. This lays the groundwork for brokered entanglement protocols with this system.

Bio: Isaac is a Ph.D. student in Electrical Engineering at MIT advised by Prof. Dirk Englund in the Quantum Photonics & AI Group. His research interests are in the prediction, characterisation and large-scale integration of solid-state defects in semiconductors for use in emerging technologies such as quantum computing and quantum communication.

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