npj Quantum Information ( IF 7.6 ) Pub Date : 2020-12-15 , DOI: 10.1038/s41534-020-00328-4 Wen-Hao Zhang , Xiao Liu , Peng Yin , Xing-Xiang Peng , Gong-Chu Li , Xiao-Ye Xu , Shang Yu , Zhi-Bo Hou , Yong-Jian Han , Jin-Shi Xu , Zong-Quan Zhou , Geng Chen , Chuan-Feng Li , Guang-Can Guo
Quantum state verification provides an efficient approach to characterize the reliability of quantum devices for generating certain target states. The figure of merit of a specific strategy is the estimated infidelity ϵ of the tested state to the target state, given a certain number of performed measurements n. Entangled measurements constitute the globally optimal strategy and achieve the scaling that ϵ is inversely proportional to n. Recent advances show that it is possible to achieve the same scaling simply with non-adaptive local measurements; however, the performance is still worse than the globally optimal bound up to a constant factor. In this work, by introducing classical communication, we experimentally implement an adaptive quantum state verification. The constant factor is minimized from ~2.5 to 1.5 in this experiment, which means that only 60% measurements are required to achieve a certain value of ϵ compared to optimal non-adaptive local strategy. Our results indicate that classical communication significantly enhances the performance of quantum state verification, and leads to an efficiency that further approaches the globally optimal bound.
中文翻译:
经典通信增强型量子态验证
量子状态验证提供了一种有效的方法来表征用于生成某些目标状态的量子设备的可靠性。一个特定的策略的品质因数是所估计的失真性ε的检查的状态到目标状态的,给定的一定数目的执行的测量的Ñ。缠结测量构成全局最优策略和实现缩放即ε成反比Ñ。最新进展表明,仅通过非自适应局部测量就可以实现相同的缩放比例。但是,在一个恒定的因素下,性能仍然不如全局最优范围。在这项工作中,通过引入经典通信,我们在实验上实现了自适应量子态验证。常数因子从2.5〜在本实验中,这意味着只有60%的测量是必需的,以实现的一定值最小化,以1.5 ε相比最佳非自适应局部策略。我们的结果表明,经典通信显着提高了量子态验证的性能,并导致进一步接近全局最优边界的效率。