论文标题
具有任意相位旋转的广义量子Pagerank算法
Generalized Quantum PageRank Algorithm with Arbitrary Phase Rotations
论文作者
论文摘要
Pagerank算法的量化是未来量子互联网的有前途的工具。在这里,我们介绍了量子pagerank的修改,该量子在基础Szegedy的量子步行中引入了任意相位旋转(APR)。我们将三个不同的APR方案定义为仅一个阶段作为一种自由度。我们已经在一个小通用图中分析了这些算法的行为,观察到该相的减少减少了瞬时Pagerank的标准偏差,因此可以更好地区分网络的节点。但是,该算法需要更多的时间来收敛,因此无法任意减少相位。通过这些结果,我们选择了该阶段的具体值,以便以后将算法应用于复杂的无标度图。在这些网络中,原始的量子Pagerank能够打破残留节点的退化,并检测经典算法抑制的次级枢纽。然而,并非所有检测到的次级枢纽都是根据Pagerank的定义真实的。一些APR方案可以克服这个问题,恢复残差节点的退化,并突出网络的真正次要枢纽。最后,我们研究了新算法的稳定性。已知原始量子算法比经典算法更稳定。我们发现,我们的Pagerank分布类似于经典的算法,具有与原始量子算法相似的稳定性。
The quantization of the PageRank algorithm is a promising tool for a future quantum internet. Here we present a modification of the quantum PageRank introducing arbitrary phase rotations (APR) in the underlying Szegedy's quantum walk. We define three different APR schemes with only one phase as a degree of freedom. We have analyzed the behavior of these algorithms in a small generic graph, observing that a decrease of the phase reduces the standard deviation of the instantaneous PageRank, so the nodes of the network can be distinguished better. However, the algorithm takes more time to converge, so the phase can not be decreased arbitrarily. With these results we choose a concrete value for the phase to later apply the algorithm to complex scale-free graphs. In these networks, the original quantum PageRank is able to break the degeneracy of the residual nodes and detect secondary hubs that the classical algorithm suppresses. Nevertheless, not all of the detected secondary hubs are real according to the PageRank's definition. Some APR schemes can overcome this problem, restoring the degeneration of the residual nodes and highlighting the truly secondary hubs of the networks. Finally, we have studied the stability of the new algorithms. The original quantum algorithm was known to be more stable than the classical. We have found that one of our algorithms, whose PageRank distribution resembles the classical one, has a stability similar to the original quantum algorithm.