Quantum State Tomography via Reduced Density Matrices
Quantum State Tomography via Reduced Density Matrices
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DOI：
10.1103/physrevlett.118.020401
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发表时间：
2017-01-09
影响因子：
8.6
通讯作者：
Laflamme, Raymond
中科院分区：
文献类型：
--
作者：
Xin, Tao;Lu, Dawei;Laflamme, Raymond
通过局域测量的量子态层析成像是表征量子态的有效工具。然而，它要求原始全局状态由其局部约化密度矩阵（RDM）唯一确定（UD）。在这项工作中，我们第一次证明了一类状态是UD的RDM的假设下，全球状态是纯的，但不能UD的情况下，该假设。这一发现使我们能够根据量子态的UD性质对量子态进行分类，并要求在简化量子态层析成像的实践中区别对待每一类。此外，我们实验测试的可行性和稳定性进行量子态层析成像通过测量本地RDM为每一类。这些理论和实验结果表明，量子态层析与本地测量的优点和可能的陷阱。
Quantum state tomography via local measurements is an efficient tool for characterizing quantum states. However, it requires that the original global state be uniquely determined (UD) by its local reduced density matrices (RDMs). In this work, we demonstrate for the first time a class of states that are UD by their RDMs under the assumption that the global state is pure, but fail to be UD in the absence of that assumption. This discovery allows us to classify quantum states according to their UD properties, with the requirement that each class be treated distinctly in the practice of simplifying quantum state tomography. Additionally, we experimentally test the feasibility and stability of performing quantum state tomography via the measurement of local RDMs for each class. These theoretical and experimental results demonstrate the advantages and possible pitfalls of quantum state tomography with local measurements.