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arXiv · 2608.03012

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

Lan-Tian Feng·Bo-Hao Zhang·Di Liu·Pan Gong·Yu-Yang Ding·Guo-Ping Guo·Guang-Can Guo·Xi-Feng Ren
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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.

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Lan-Tian Feng, Bo-Hao Zhang, Di Liu, Pan Gong, Yu-Yang Ding, Guo-Ping Guo, Guang-Can Guo, Xi-Feng Ren. 2026-08-04. On-chip generation of multi-qubit graph states with high-dimensional encoded single photons. https://arxiv.org/abs/2608.03012

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