Jian-Wei Pan

Solving Systems of Linear Equations with a Superconducting Quantum Processor

  1. Yarui Zheng,
  2. Chao Song,
  3. Ming-Cheng Chen,
  4. Benxiang Xia,
  5. Wuxin Liu,
  6. Qiujiang Guo,
  7. Libo Zhang,
  8. Da Xu,
  9. Hui Deng,
  10. Keqiang Huang,
  11. Yulin Wu,
  12. Zhiguang Yan,
  13. Dongning Zheng,
  14. Li Lu,
  15. Jian-Wei Pan,
  16. H. Wang,
  17. Chao-Yang Lu,
  18. and Xiaobo Zhu
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±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.
arxiv pdf

Emulating anyonic fractional statistical behavior in a superconducting quantum circuit

  1. Y. P. Zhong,
  2. D. Xu,
  3. P. Wang,
  4. C. Song,
  5. Q. J. Guo,
  6. W. X. Liu,
  7. K. Xu,
  8. B. X. Xia,
  9. Chao-Yang Lu,
  10. Siyuan Han,
  11. Jian-Wei Pan,
  12. and Haohua Wang
Anyons are exotic quasiparticles obeying fractional statistics,whose behavior can be emulated in artificially designed spin systems.Here we present an experimental emulation of creating
anyonic excitations in a superconducting circuit that consists of four qubits, achieved by dynamically generating the ground and excited states of the toric code model, i.e., four-qubit Greenberger-Horne-Zeilinger states. The anyonic braiding is implemented via single-qubit rotations: a phase shift of \pi related to braiding, the hallmark of Abelian 1/2 anyons, has been observed through a Ramsey-type interference measurement.
arxiv pdf