On-chip generation of multi-qubit graph states with high-dimensional encoded single photons

Abstract:Photonic multi-qubit entanglement is key to optical quantum information processing, particularly universal quantum computing. Yet multi-photon sources suffer from low emission efficiency, making single-photon high-dimensional encoding an appealing alternative. Here we propose an explicit and resource-efficient high-dimensional encoding approach to achieve the target multi-qubit quantum state. The technically challenging preparation of multi-photon quantum states is replaced by single-photon operations involving high-dimensional expansion, routing, and multi-layered quantum measurement. Besides, each photon in the resource multi-photon quantum state can be used to encode multiple qubits in a distributed manner, and a larger entangled state will be constructed. We demonstrate this approach using programmable photonic integrated circuits, where multi-qubit graph states--including the Greenberger-Horne-Zeilinger state and the cluster state--are generated and characterized. We additionally demonstrate the Grover search algorithm using the single-photon cluster state. Our findings unlock a novel route towards diverse entangled state generation with photons and advance large-scale and universal photonic quantum information processing.

arXiv:2608.03012 [quant-ph]

(or arXiv:2608.03012v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2608.03012 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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