@article{Zhang:2020:10.1103/PhysRevLett.125.030506,
author = {Zhang, W-H and Zhang, C and Chen, Z and Peng, X-X and Xu, X-Y and Yin, P and Yu, S and Ye, X-J and Han, Y-J and Xu, J-S and Chen, G and Li, C-F and Guo, G-C},
doi = {10.1103/PhysRevLett.125.030506},
journal = {Phys Rev Lett},
title = {Experimental Optimal Verification of Entangled States Using Local Measurements.},
url = {http://dx.doi.org/10.1103/PhysRevLett.125.030506},
volume = {125},
year = {2020}
}

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TY  - JOUR
AB  - The initialization of a quantum system into a certain state is a crucial aspect of quantum information science. While a variety of measurement strategies have been developed to characterize how well the system is initialized, for a given one, there is in general a trade-off between its efficiency and the accessible information of the quantum state. Conventional quantum state tomography can characterize unknown states while requiring exponentially expensive time-consuming postprocessing. Alternatively, recent theoretical breakthroughs show that quantum state verification provides a technique to quantify the prepared state with significantly fewer samples, especially for multipartite entangled states. In this Letter, we modify the original proposal to be robust to practical imperfections, and experimentally implement a scalable quantum state verification on two-qubit and four-qubit entangled states with nonadaptive local measurements. For all the tested states, the estimated infidelity is inversely proportional to the number of samples, which illustrates the power to characterize a quantum state with a small number of samples. Compared to the globally optimal strategy which requires nonlocal measurements, the efficiency in our experiment is only worse by a small constant factor (<2.5). We compare the performance difference between quantum state verification and quantum state tomography in an experiment to characterize a four-photon Greenberger-Horne-Zeilinger state, and the results indicate the advantage of quantum state verification in both the achieved efficiency and precision.
AU  - Zhang,W-H
AU  - Zhang,C
AU  - Chen,Z
AU  - Peng,X-X
AU  - Xu,X-Y
AU  - Yin,P
AU  - Yu,S
AU  - Ye,X-J
AU  - Han,Y-J
AU  - Xu,J-S
AU  - Chen,G
AU  - Li,C-F
AU  - Guo,G-C
DO  - 10.1103/PhysRevLett.125.030506
PY  - 2020///
TI  - Experimental Optimal Verification of Entangled States Using Local Measurements.
T2  - Phys Rev Lett
UR  - http://dx.doi.org/10.1103/PhysRevLett.125.030506
UR  - https://www.ncbi.nlm.nih.gov/pubmed/32745389
VL  - 125
ER  - 

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