Yan Wen-Zhe, Li Yunting, Hou Zhibo, Zhu Huangjun, Xiang Guo-Yong, Li Chuan-Feng, Guo Guang-Can
CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, People's Republic of China.
CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China.
Phys Rev Lett. 2024 Feb 23;132(8):080202. doi: 10.1103/PhysRevLett.132.080202.
Quantum measurements based on mutually unbiased bases (MUBs) play crucial roles in foundational studies and quantum information processing. It is known that there exist inequivalent MUBs, but little is known about their operational distinctions, not to say experimental demonstration. In this Letter, by virtue of a simple estimation problem, we experimentally demonstrate the operational distinctions between inequivalent triples of MUBs in dimension 4 based on high-precision photonic systems. The experimental estimation fidelities coincide well with the theoretical predictions with only 0.16% average deviation, which is 25 times less than the difference (4.1%) between the maximum estimation fidelity and the minimum estimation fidelity. Our experiments clearly demonstrate that inequivalent MUBs have different information extraction capabilities and different merits for quantum information processing.
基于相互无偏基（MUBs）的量子测量在基础研究和量子信息处理中起着至关重要的作用。已知存在不等价的相互无偏基，但对于它们的操作差异却知之甚少，更不用说实验证明了。在本信函中，借助一个简单的估计问题，我们基于高精度光子系统通过实验证明了四维中不等价的相互无偏基三元组之间的操作差异。实验估计保真度与理论预测吻合良好，平均偏差仅为0.16%，这比最大估计保真度与最小估计保真度之间的差异（4.1%）小25倍。我们的实验清楚地表明，不等价的相互无偏基具有不同的信息提取能力以及在量子信息处理方面的不同优势。
