Continuous-variable geometric phase and its manipulation for quantum computation in a superconducting circuit

  1. Chao Song,
  2. Shi-Biao Zheng,
  3. Pengfei Zhang,
  4. Kai Xu,
  5. Libo Zhang,
  6. Qiujiang Guo,
  7. Wuxin Liu,
  8. Da Xu,
  9. Hui Deng,
  10. Keqiang Huang,
  11. Dongning Zheng,
  12. Xiaobo Zhu,
  13. and H. Wang
Geometric phase, associated with holonomy transformation in quantum state space, is an important quantum-mechanical effect. Besides fundamental interest, this effect has practical applications, among which geometric quantum computation is a paradigm, where quantum logic operations are realized through geometric phase manipulation that has some intrinsic noise-resilient advantages and may enable simplified implementation of multiqubit gates compared to the dynamical approach. Here we report observation of a continuous-variable geometric phase and demonstrate a quantum gate protocol based on this phase in a superconducting circuit, where five qubits are controllably coupled to a resonator. Our geometric approach allows for one-step implementation of n-qubit controlled-phase gates, which represents a remarkable advantage compared to gate decomposition methods, where the number of required steps dramatically increases with n. Following this approach, we realize these gates with n up to 4, verifying the high efficiency of this geometric manipulation for quantum computation.
arxiv pdf

leave comment