TY - JOUR T1 - Closing the Locality and Detection Loopholes in Multiparticle Entanglement Self-Testing JF - Physical Review Letters Y1 - 2022 A1 - Dian Wu A1 - Qi Zhao A1 - Can Wang A1 - Liang Huang A1 - Yang-Fan Jiang A1 - Bing Bai A1 - You Zhou A1 - Xue-Mei Gu A1 - Feng-Ming Liu A1 - Ying-Qiu Mao A1 - Qi-Chao Sun A1 - Ming-Cheng Chen A1 - Jun Zhang A1 - Cheng-Zhi Peng A1 - Xiao-Bo Zhu A1 - Qiang Zhang A1 - Chao-Yang Lu A1 - Jian-Wei Pan AB -

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.

VL - 128 U4 - 250401 UR - 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 CP - 25 U5 - https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.128.250401 ER - TY - JOUR T1 - A scheme to create and verify scalable entanglement in optical lattice JF - npj Quantum Information Y1 - 2022 A1 - You Zhou A1 - Bo Xiao A1 - Meng-Da Li A1 - Qi Zhao A1 - Zhen-Sheng Yuan A1 - Xiongfeng Ma A1 - Jian-Wei Pan AB -

To achieve scalable quantum information processing, great efforts have been devoted to the creation of large-scale entangled states in various physical systems. Ultracold atom in optical lattice is considered as one of the promising platforms due to its feasible initialization and parallel manipulation. In this work, we propose an efficient scheme to generate and characterize global entanglement in the optical lattice. With only two-layer quantum circuits, the generation utilizes two-qubit entangling gates based on the superexchange interaction in double wells. The parallelism of these operations enables the generation to be fast and scalable. To verify the entanglement of this non-stabilizer state, we mainly design three complementary detection protocols which are less resource-consuming compared to the full tomography. In particular, one just needs two homogenous local measurement settings to identify the entanglement property. Our entanglement generation and verification protocols provide the foundation for the further quantum information processing in optical lattice.

VL - 8 UR - https://arxiv.org/abs/2209.01531 U5 - 10.1038/s41534-022-00609-0 ER - TY - JOUR T1 - Robust Self-Testing of Multiparticle Entanglement JF - Phys. Rev. Lett. Y1 - 2021 A1 - Dian Wu A1 - Qi Zhao A1 - Xue-Mei Gu A1 - Han-Sen Zhong A1 - You Zhou A1 - Li-Chao Peng A1 - Jian Qin A1 - Yi-Han Luo A1 - Kai Chen A1 - Li Li A1 - Nai-Le Liu A1 - Chao-Yang Lu A1 - Jian-Wei Pan AB -

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.

VL - 127 U4 - 230503 UR - https://arxiv.org/abs/2105.10298 U5 - https://doi.org/10.1103/PhysRevLett.127.230503 ER -