%0 Journal Article %J Physical Review Letters %D 2022 %T Closing the Locality and Detection Loopholes in Multiparticle Entanglement Self-Testing %A Dian Wu %A Qi Zhao %A Can Wang %A Liang Huang %A Yang-Fan Jiang %A Bing Bai %A You Zhou %A Xue-Mei Gu %A Feng-Ming Liu %A Ying-Qiu Mao %A Qi-Chao Sun %A Ming-Cheng Chen %A Jun Zhang %A Cheng-Zhi Peng %A Xiao-Bo Zhu %A Qiang Zhang %A Chao-Yang Lu %A Jian-Wei Pan %X

First proposed by Mayers and Yao, self-testing provides a certification method to infer the underlying physics of quantum experiments in a black-box scenario. Numerous demonstrations have been reported to self-test various types of entangled states. However, all the multiparticle self-testing experiments reported so far suffer from both detection and locality loopholes. Here, we report the first experimental realization of multiparticle entanglement self-testing closing the locality loophole in a photonic system, and the detection loophole in a superconducting system, respectively. We certify three-party and four-party GHZ states with at least 0.84 (1) and 0.86 (3) fidelities in a device-independent way. These results can be viewed as a meaningful advance in multiparticle loophole-free self-testing, and also significant progress on the foundations of quantum entanglement certification.

%B Physical Review Letters %V 128 %P 250401 %8 06/23/2022 %G eng %U https://www.researchgate.net/profile/Dian-Wu/publication/361497881_Closing_the_Locality_and_Detection_Loopholes_in_Multiparticle_Entanglement_Self-Testing/links/62b55a8c1010dc02cc57530c/Closing-the-Locality-and-Detection-Loopholes-in-Multiparticle-Entangl %N 25 %R https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.128.250401 %0 Journal Article %J Phys. Rev. Lett. %D 2021 %T Robust Self-Testing of Multiparticle Entanglement %A Dian Wu %A Qi Zhao %A Xue-Mei Gu %A Han-Sen Zhong %A You Zhou %A Li-Chao Peng %A Jian Qin %A Yi-Han Luo %A Kai Chen %A Li Li %A Nai-Le Liu %A Chao-Yang Lu %A Jian-Wei Pan %X

Quantum self-testing is a device-independent way to certify quantum states and measurements using only the input-output statistics, with minimal assumptions about the quantum devices. Due to the high demand on tolerable noise, however, experimental self-testing was limited to two-photon systems. Here, we demonstrate the first robust self-testing for multi-particle quantum entanglement. We prepare two examples of four-photon graph states, the Greenberger-Horne-Zeilinger (GHZ) states with a fidelity of 0.957(2) and the linear cluster states with a fidelity of 0.945(2). Based on the observed input-output statistics, we certify the genuine four-photon entanglement and further estimate their qualities with respect to realistic noise in a device-independent manner.

%B Phys. Rev. Lett. %V 127 %P 230503 %8 12/7/2021 %G eng %U https://arxiv.org/abs/2105.10298 %R https://doi.org/10.1103/PhysRevLett.127.230503