Zheng Yarui, Song Chao, Chen Ming-Cheng, Xia Benxiang, Liu Wuxin, Guo Qiujiang, Zhang Libo, Xu Da, Deng Hui, Huang Keqiang, Wu Yulin, Yan Zhiguang, Zheng Dongning, Lu Li, Pan Jian-Wei, Wang H, Lu Chao-Yang, Zhu Xiaobo
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Phys Rev Lett. 2017 May 26;118(21):210504. doi: 10.1103/PhysRevLett.118.210504.
Superconducting quantum circuits are a 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. 103, 150502 (2009)PRLTAO0031-900710.1103/PhysRevLett.103.150502], which promises an exponential speedup over classical algorithms under certain circumstances. We benchmark the solver with quantum inputs and outputs, and characterize it by nontrace-preserving quantum process tomography, which yields a process fidelity of 0.837±0.006. Our results highlight the potential of superconducting quantum circuits for applications in solving large-scale linear systems, a ubiquitous task in science and engineering.
超导量子电路是构建可扩展量子计算机的一个有前途的候选方案。在此，我们使用一个四比特超导量子处理器，基于哈罗、哈西迪姆和劳埃德提出的量子算法[《物理评论快报》103, 150502 (2009年)PRLTAO0031 - 900710.1103/PhysRevLett.103.150502]来求解二维线性方程组，该算法在某些情况下有望比经典算法实现指数级加速。我们用量子输入和输出对求解器进行基准测试，并通过非保迹量子过程层析成像对其进行表征，得到的过程保真度为0.837±0.006。我们的结果凸显了超导量子电路在解决大规模线性系统方面的应用潜力，这是科学和工程中一项普遍存在的任务。
