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arXiv · 2607.12250

Experimental demonstration of scalable quantum blockchain with exponentially superior quantum communication complexity

Feng Xie·Ming-Yang Li·Yongqiang Du·Chen-Xun Weng·Mingxuan Zhang·Xin Hua·Xiang Guan·Xin An·Jingzhe He·Xin Liu·Zhenrong Zhang·Xi Xiao·Hua-Lei Yin·Kejin Wei
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Abstract

To secure modern distributed digital infrastructures, quantum blockchains exploit quantum resources to achieve information-theoretic security and surpass the classical one-third fault-tolerance bound. However, existing high-fault-tolerant protocols face a fundamental scalability challenge: the blockchain trilemma imposes either exponential communication complexity or experimentally demanding multipartite entanglement. Here, we experimentally demonstrate a scalable quantum blockchain protocol based on weak coherent states that achieves an exponential reduction in quantum communication complexity. The protocol employs a circular quantum Byzantine agreement mechanism that preserves information-theoretic security while avoiding multipartite entanglement. We implement this protocol on a photonic integrated circuit platform, realizing a six-node network over commercially available telecommunication infrastructure. Compared with previous schemes, the protocol requires less than 4% of the quantum communication resources. Leveraging this advantage, we further demonstrate a quantum-secured token exchange application achieving a throughput of 805.3 transactions per second with zero failures. These results establish a practical pathway toward scalable quantum blockchain.

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Feng Xie, Ming-Yang Li, Yongqiang Du, Chen-Xun Weng, Mingxuan Zhang, Xin Hua, Xiang Guan, Xin An, Jingzhe He, Xin Liu, Zhenrong Zhang, Xi Xiao, Hua-Lei Yin, Kejin Wei. 2026-07-14. Experimental demonstration of scalable quantum blockchain with exponentially superior quantum communication complexity. https://arxiv.org/abs/2607.12250

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