中文

Clifford 层级第三层置换门的表征

量子物理 2025-10-07 v1

摘要

Clifford 层级是量子计算中一个基本结构,其数学性质尚未完全理解。本文对层级第三层的置换门进行表征——这些是置换 2n2^n 基状态的单位算子。我们证明,层级第三层的任何置换门都是 Clifford 置换门的左右乘积下以阶梯形式的 Toffoli 门的乘积。随后,我们给出阶梯形式置换门是否属于层级第三层的必要充分条件。作为推论,我们构造了一个非半-Clifford 置换门族 {Uk}k3\{U_k\}_{k\geq 3},其中每个 UkU_k 属于层级第三层,但其逆向不属于第 kk 层。

关键词

引用

@article{arxiv.2510.04993,
  title  = {Characterization of permutation gates in the third level of the Clifford hierarchy},
  author = {Zhiyang He and Luke Robitaille and Xinyu Tan},
  journal= {arXiv preprint arXiv:2510.04993},
  year   = {2025}
}

备注

Supersedes arXiv:2410.11818, which established only a necessary but not sufficient condition for a permutation gate to lie in the third level of the Clifford hierarchy, and did not include the gates $U_k$ described in the abstract of the present paper