Wenjie Jiang

Long-lived topological time-crystalline order on a quantum processor

  1. Liang Xiang,
  2. Wenjie Jiang,
  3. Zehang Bao,
  4. Zixuan Song,
  5. Shibo Xu,
  6. Ke Wang,
  7. Jiachen Chen,
  8. Feitong Jin,
  9. Xuhao Zhu,
  10. Zitian Zhu,
  11. Fanhao Shen,
  12. Ning Wang,
  13. Chuanyu Zhang,
  14. Yaozu Wu,
  15. Yiren Zou,
  16. Jiarun Zhong,
  17. Zhengyi Cui,
  18. Aosai Zhang,
  19. Ziqi Tan,
  20. Tingting Li,
  21. Yu Gao,
  22. Jinfeng Deng,
  23. Xu Zhang,
  24. Hang Dong,
  25. Pengfei Zhang,
  26. Si Jiang,
  27. Weikang Li,
  28. Zhide Lu,
  29. Zheng-Zhi Sun,
  30. Hekang Li,
  31. Zhen Wang,
  32. Chao Song,
  33. Qiujiang Guo,
  34. Fangli Liu,
  35. Zhe-Xuan Gong,
  36. Alexey V. Gorshkov,
  37. Norman Y. Yao,
  38. Thomas Iadecola,
  39. Francisco Machado,
  40. H. Wang,
  41. and Dong-Ling Deng
Topologically ordered phases of matter elude Landau’s symmetry-breaking theory, featuring a variety of intriguing properties such as long-range entanglement and intrinsic robustness
against local perturbations. Their extension to periodically driven systems gives rise to exotic new phenomena that are forbidden in thermal equilibrium. Here, we report the observation of signatures of such a phenomenon — a prethermal topologically ordered time crystal — with programmable superconducting qubits arranged on a square lattice. By periodically driving the superconducting qubits with a surface-code Hamiltonian, we observe discrete time-translation symmetry breaking dynamics that is only manifested in the subharmonic temporal response of nonlocal logical operators. We further connect the observed dynamics to the underlying topological order by measuring a nonzero topological entanglement entropy and studying its subsequent dynamics. Our results demonstrate the potential to explore exotic topologically ordered nonequilibrium phases of matter with noisy intermediate-scale quantum processors.
arxiv pdf

Observation of a symmetry-protected topological time crystal with superconducting qubits

  1. Xu Zhang,
  2. Wenjie Jiang,
  3. Jinfeng Deng,
  4. Ke Wang,
  5. Jiachen Chen,
  6. Pengfei Zhang,
  7. Wenhui Ren,
  8. Hang Dong,
  9. Shibo Xu,
  10. Yu Gao,
  11. Feitong Jin,
  12. Xuhao Zhu,
  13. Qiujiang Guo,
  14. Hekang Li,
  15. Chao Song,
  16. Zhen Wang,
  17. Dong-Ling Deng,
  18. and H. Wang
We report the observation of a symmetry-protected topological time crystal, which is implemented with an array of programmable superconducting qubits. Unlike the time crystals reported
in previous experiments, where spontaneous breaking of the discrete time translational symmetry occurs for local observables throughout the whole system, the topological time crystal observed in our experiment breaks the time translational symmetry only at the boundaries and has trivial dynamics in the bulk. More concretely, we observe robust long-lived temporal correlations and sub-harmonic temporal response for the edge spins up to 40 driving cycles. We demonstrate that the sub-harmonic response is independent of whether the initial states are random product states or symmetry-protected topological states, and experimentally map out the phase boundary between the time crystalline and thermal phases. Our work paves the way to exploring peculiar non-equilibrium phases of matter emerged from the interplay between topology and localization as well as periodic driving, with current noisy intermediate-scale quantum processors.
arxiv pdf