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arXiv · 2505.05582

Quantum-network nodes with real-time noise mitigation using spectator qubits

S. J. H. Loenen·Y. Wang·N. Demetriou·C. E. Bradley·T. H. Taminiau
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Abstract

Quantum networks might enable quantum communication and distributed quantum computation. Solid-state defects are promising platforms for such networks, because they provide an optical interface for remote entanglement distribution and a nuclear-spin register to store and process quantum information. A key challenge towards larger networks is to improve the storage of previously generated entangled states during new entanglement generation. Here, we introduce a method that uses `spectator' qubits combined with real-time decision making and feedforward to mitigate dephasing of stored quantum states during remote entanglement sequences. We implement the protocol using a single NV center in diamond and demonstrate improved memory fidelity. Our results show that spectator qubits can improve quantum network memory using minimal overhead and naturally present resources, making them a promising addition for near-term testbeds for quantum networks.

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S. J. H. Loenen, Y. Wang, N. Demetriou, C. E. Bradley, T. H. Taminiau. 2025-05-08. Quantum-network nodes with real-time noise mitigation using spectator qubits. https://doi.org/10.1103/zgm8-6b8l

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