School of Physics, Beijing Institute of Technology, Beijing, 100081, China.
Sci Rep. 2017 Jul 10;7(1):4962. doi: 10.1038/s41598-017-04795-2.
Quantum walk (QW) provides a versatile platform for the realization of quantum algorithms. Due to the existence of the inevitable noises in the walk, the different quantum algorithms accommodating to different noises are demanded. Thus, the success of the algorithms based on the QW requires us to sense different noises in the walk. Until now, the way to distinguish different noises in the walk has been discussed rarely. Here, we propose an efficient way to sense the noises in the one and two dimensional QWs. The populations of the coin in the walk with or without decoherence are presented. By only detecting the populations of the coin in the QW, we can determine whether there exists the decoherence in the total QW system. Moreover, the non-Markovianity of the coin in the one and two dimensional QWs is revealed, in which the coin is taken as an open quantum system, and the other components of the QW system is taken as the large environment. With the measured value of the non-Markovianity for the coin, we can conjecture which kinds of noise emerges in the one and two dimensional QWs.
量子漫步（QW）为实现量子算法提供了一个通用的平台。由于漫步过程中存在不可避免的噪声，因此需要适应不同噪声的不同量子算法。因此，基于 QW 的算法的成功需要我们感知漫步过程中的不同噪声。到目前为止，很少有关于区分漫步中不同噪声的方法。在这里，我们提出了一种有效感知一维和二维 QW 中噪声的方法。展示了漫步中带或不带退相干的硬币的数量。通过仅检测 QW 中硬币的数量，我们可以确定总 QW 系统中是否存在退相干。此外，揭示了一维和二维 QW 中硬币的非马尔可夫性，其中将硬币视为开放量子系统，而 QW 系统的其他组件则视为大环境。通过测量硬币的非马尔可夫性值，我们可以推测一维和二维 QW 中出现了哪种噪声。
