论文标题
带有变异电路的拉普拉斯征本图:图形数据的量子嵌入
Laplacian Eigenmaps with variational circuits: a quantum embedding of graph data
论文作者
论文摘要
随着量子算法的发展,为了获得量子优势,对高成本计算进行了审查。尽管图形为多个现实世界问题提供了方便的框架,但它们的分析仍然带有高计算和空间。通过将图数据映射到一个低维空间中,在该空间中保留图形结构信息,Laplacian矩阵的特征向量构成了强大的节点嵌入,称为Laplacian eigenmaps。知道这些嵌入是一项昂贵的任务,因为它知道使用特定的稀疏方法,laplacian矩阵的特征composition的成本为o($ rn^2 $),$ r $是非零元素的比例。 我们提出了一种使用量子变异电路计算拉普拉斯本征图的方法。我们算法的想法是通过调整变异量子量化算法算法来达到拉普拉斯矩阵的特征状态,该矩阵可以被视为汉密尔顿操作员。通过同时估算Laplacian的$ d $第一特征向量,我们的算法直接生成了该图的$ d $ dimension量子嵌入。我们证明,可以通过在其顶部实现量子分类器来将嵌入式用于图形机学习任务。整个电路由完整的量子节点分类算法组成。使用量子模拟器上的32个节点图的测试表明,我们可以实现与经典laplacian eigenmap算法相似的性能。尽管这种近似方法的数学特性尚未完全理解,但该算法为使用嘈杂的量子计算机提供了预处理的观点。
With the development of quantum algorithms, high-cost computations are being scrutinized in the hope of a quantum advantage. While graphs offer a convenient framework for multiple real-world problems, their analytics still comes with high computation and space. By mapping the graph data into a low dimensional space, in which graph structural information is preserved, the eigenvectors of the Laplacian matrix constitute a powerful node embedding, called Laplacian Eigenmaps. Computing these embeddings is on its own an expensive task knowing that using specific sparse methods, the eigendecomposition of a Laplacian matrix has a cost of O($rn^2$), $r$ being the ratio of nonzero elements. We propose a method to compute a Laplacian Eigenmap using a quantum variational circuit. The idea of our algorithm is to reach the eigenstates of the laplacian matrix, which can be considered as a hamiltonian operator, by adapting the variational quantum eigensolver algorithm. By estimating the $d$ first eigenvectors of the Laplacian at the same time, our algorithm directly generates a $d$ dimension quantum embedding of the graph. We demonstrate that it is possible to use the embedding for graph machine learning tasks by implementing a quantum classifier on the top of it. The overall circuit consists in a full quantum node classification algorithm. Tests on 32 nodes graph with a quantum simulator shows that we can achieve similar performances as the classical laplacian eigenmap algorithm. Although mathematical properties of this approximate approach are not fully understood, this algorithm opens perspectives for graph pre-processing using noisy quantum computers.