Zhao Jiaqiang, Wang Meijiao, Cao Lianzhen, Yang Yang, Liu Xia, Zhang Qinwei, Lu Huaixin, Driscoll Kellie Ann
Department of Physics and Optoelectronic Engineering, Weifang University, Weifang 261061, China.
Entropy (Basel). 2021 Nov 15;23(11):1514. doi: 10.3390/e23111514.
Knowing the level of entanglement robustness against quantum bit loss or decoherence mechanisms is an important issue for any application of quantum information. Fidelity of states can be used to judge whether there is entanglement in multi-particle systems. It is well known that quantum channel security in QKD can be estimated by measuring the robustness of Bell-type inequality against noise. We experimentally investigate a new Bell-type inequality (NBTI) in the three-photon Greenberger-Horne-Zeilinger (GHZ) states with different levels of spin-flip noise. The results show that the fidelity and the degree of violation of the NBTI decrease monotonically with the increase of noise intensity. They also provide a method to judge whether there is entanglement in three-particle mixed states.
对于量子信息的任何应用而言，了解纠缠对量子比特丢失或退相干机制的鲁棒性水平都是一个重要问题。态的保真度可用于判断多粒子系统中是否存在纠缠。众所周知，量子密钥分发中的量子信道安全性可通过测量贝尔型不等式对噪声的鲁棒性来估计。我们通过实验研究了处于不同自旋翻转噪声水平的三光子格林伯格-霍恩-泽林格（GHZ）态中的一种新的贝尔型不等式（NBTI）。结果表明，NBTI的保真度和违背程度随噪声强度的增加而单调降低。它们还提供了一种判断三粒子混合态中是否存在纠缠的方法。
