K. Xu

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

Suppression of dephasing by qubit motion in superconducting circuits

  1. D.V. Averin,
  2. K. Xu,
  3. Y. P. Zhong,
  4. C. Song,
  5. H. Wang,
  6. and Siyuan Han
We suggest and demonstrate a protocol which suppresses dephasing due to the low-frequency noise by qubit motion, i.e., transfer of the logical qubit of information in a system of n≥2
physical qubits. The protocol requires only the nearest-neighbor coupling and is applicable to different qubit structures. We further analyze its effectiveness against noises with arbitrary correlations. Our analysis, together with experiments using up to three superconducting qubits, shows that for the realistic uncorrelated noises, qubit motion increases the dephasing time of the logical qubit as n‾‾√. In general, the protocol provides a diagnostic tool to measure the noise correlations.
arxiv pdf