



02045nas a2200337   4500008004100000245009200041210006900133260001500202300001100217490000800228520091000236100001301146700001301159700001401172700001701186700002001203700001401223700001401237700001601251700001901267700001801286700001701304700002101321700001501342700002001357700001701377700001701394700001801411700001801429856026001447       2022                        eng d00aClosing the Locality and Detection Loopholes in Multiparticle Entanglement Self-Testing0 aClosing the Locality and Detection Loopholes in Multiparticle En  c06/23/2022  a2504010 v1283 a<p>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.</p>1 aWu, Dian1 aZhao, Qi1 aWang, Can1 aHuang, Liang1 aJiang, Yang-Fan1 aBai, Bing1 aZhou, You1 aGu, Xue-Mei1 aLiu, Feng-Ming1 aMao, Ying-Qiu1 aSun, Qi-Chao1 aChen, Ming-Cheng1 aZhang, Jun1 aPeng, Cheng-Zhi1 aZhu, Xiao-Bo1 aZhang, Qiang1 aLu, Chao-Yang1 aPan, Jian-Wei  uhttps://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-Entangl01854nas a2200121   4500008004100000245006500041210006500106260001300171520148400184100001301668700001401681856003701695       2020                        eng d00aConstructing Multipartite Bell inequalities from stabilizers0 aConstructing Multipartite Bell inequalities from stabilizers  c2/5/20203 a<p>Bell inequality with self-testing property has played an important role in quantum information field with both fundamental and practical applications. However, it is generally challenging to find Bell inequalities with self-testing property for multipartite states and actually there are not many known candidates. In this work, we propose a systematical framework to construct Bell inequalities from stabilizers which are maximally violated by general stabilizer states, with two observables for each local party. We show that the constructed Bell inequalities can self-test any stabilizer state which is essentially device-independent, if and only if these stabilizers can uniquely determine the state in a device-dependent manner. This bridges the gap between device-independent and device-dependent verification methods. Our framework can provide plenty of Bell inequalities for self-testing stabilizer states. Among them, we give two families of Bell inequalities with different advantages: (1) a family of Bell inequalities with a constant ratio of quantum and classical bounds using 2N correlations, (2) Single pair inequalities improving on all previous robustness self-testing bounds using N+1 correlations, which are both efficient and suitable for realizations in multipartite systems. Our framework can not only inspire more fruitful multipartite Bell inequalities from conventional verification methods, but also pave the way for their practical applications.</p>1 aZhao, Qi1 aZhou, You  uhttps://arxiv.org/abs/2002.01843