Solving Systems of Linear Equations with a Superconducting Quantum Processor

Yarui Zheng, Chao Song, Ming-Cheng Chen, Benxiang Xia, Wuxin Liu, Qiujiang Guo, Libo Zhang, Da Xu, Hui Deng, Keqiang Huang, Yulin Wu, Zhiguang Yan, Dongning Zheng, Li Lu, Jian-Wei Pan, H. Wang, Chao-Yang Lu, Xiaobo Zhu

Published 2017-03-20Version 1

Superconducting quantum circuits are promising candidate for building scalable quantum computers. Here, we use a four-qubit superconducting quantum processor to solve a two-dimensional system of linear equations based on a quantum algorithm proposed by Harrow, Hassidim, and Lloyd [Phys. Rev. Lett. \textbf{103}, 150502 (2009)], which promises an exponential speedup over classical algorithms under certain circumstances. We benchmark the solver with quantum inputs and outputs, and characterize it by non-trace-preserving quantum process tomography, which yields a process fidelity of $0.837\pm0.006$. Our results highlight the potential of superconducting quantum circuits for applications in solving large-scale linear systems, a ubiquitous task in science and engineering.