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Silicon offers a rare combination of mature photonic integration and a low-noise host environment for solid-state spins, making it a promising platform for scalable quantum networks. I will present recent progress with T centers—carbon-hydrogen defects in silicon—that provide optically addressable electron and nuclear spin qubits with telecom O-band optical transitions. I will focus first on coherent spin control and optical readout in integrated silicon photonics, including a three-qubit register formed by a T-center electron spin coupled to nearby hydrogen and silicon nuclear spins. Using this register, we demonstrate long spin coherence, two-qubit nuclear gates, and entanglement between nuclear spin qubits, establishing T centers as a multi-qubit quantum memory with an optical interface. I will then briefly discuss the photonic ingredients needed to connect these memories: photonic crystal cavity arrays coupled to bus waveguides for wavelength-multiplexed emission, and measurements identifying laser-induced spectral diffusion as a key source of optical linewidth broadening. Together, these results show how silicon T centers can combine local spin registers with scalable photonic integration, providing key building blocks for silicon-based quantum networks.

Xueyue (Sherry) Zhang is an Assistant Professor of Applied Physics at Columbia University. She earned her B.Eng. from Tsinghua University and her Ph.D. in Applied Physics from Caltech, followed by a Postdoc training at UC Berkeley. Dr. Zhang's research interests include superconducting circuits, quantum many-body simulations, and color centers in silicon. Her work has earned her several awards, including Scialog Fellow, Miller Postdoc Fellowship, the Boeing Quantum Creator Prize, and the Rising Star in Physics.