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arXiv · 2312.01651

Experimental Realization of Genuine Three-copy Collective Measurements for Optimal Information Extraction

Kai Zhou·Changhao Yi·Wen-Zhe Yan·Zhibo Hou·Huangjun Zhu·Guo-Yong Xiang·Chuan-Feng Li·Guang-Can Guo
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Abstract

Nonclassical phenomena tied to entangled states are the focus of foundational studies and powerful resources in many applications. By contrast, the counterparts in quantum measurements are still poorly understood. Notably, genuine multipartite nonclassicality is barely discussed, let alone its experimental realization. Here we experimentally demonstrate the power of genuine tripartite nonclassicality in quantum measurements based on a simple estimation problem. To this end we realize an optimal genuine three-copy collective measurement via a nine-step two-dimensional photonic quantum walk with 30 elaborately designed coin operators. Then we realize an optimal estimation protocol and achieve an unprecedented high estimation fidelity, which can beat all strategies based on restricted collective measurements by more than 11 standard deviations. These results clearly demonstrate that genuine collective measurements can extract more information than local measurements and restricted collective measurements. Our work opens the door for exploring genuine multipartite nonclassical measurements and their power in quantum information processing.

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Kai Zhou, Changhao Yi, Wen-Zhe Yan, Zhibo Hou, Huangjun Zhu, Guo-Yong Xiang, Chuan-Feng Li, Guang-Can Guo. 2025-06-17. Experimental Realization of Genuine Three-copy Collective Measurements for Optimal Information Extraction. https://doi.org/10.1103/physrevlett.134.210201

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