中国物理B ›› 2013, Vol. 22 ›› Issue (5): 50304-050304.doi: 10.1088/1674-1056/22/5/050304

• GENERAL • 上一篇    下一篇

Finding symmetries of trees using continuous-time quantum walk

吴俊杰a b, 张百达a b, 唐玉华a b, 强晓刚c, 王会权a b   

  1. a State Key Laboratory of High Performance Computing, National University of Defense Technology, Changsha 410073, China;
    b School of Computer, National University of Defense Technology, Changsha 410073, China;
    c Center for Quantum Photonics, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol,Merchant Venturers Building, Woodland Road, Bristol BS8 1UB, UK
  • 收稿日期:2012-09-08 修回日期:2012-11-23 出版日期:2013-04-01 发布日期:2013-04-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 61003082).

Finding symmetries of trees using continuous-time quantum walk

Wu Jun-Jie (吴俊杰)a b, Zhang Bai-Da (张百达)a b, Tang Yu-Hua (唐玉华)a b, Qiang Xiao-Gang (强晓刚)c, Wang Hui-Quan (王会权)a b   

  1. a State Key Laboratory of High Performance Computing, National University of Defense Technology, Changsha 410073, China;
    b School of Computer, National University of Defense Technology, Changsha 410073, China;
    c Center for Quantum Photonics, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol,Merchant Venturers Building, Woodland Road, Bristol BS8 1UB, UK
  • Received:2012-09-08 Revised:2012-11-23 Online:2013-04-01 Published:2013-04-01
  • Contact: Wu Jun-Jie E-mail:junjiewu@nudt.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 61003082).

摘要: Quantum walk, the quantum counterpart of random walk, is an important model and widely studied to develop new quantum algorithms. This paper studies the relationship between the continuous-time quantum walk and the symmetry of a graph, especially that of a tree. Firstly, we prove in mathematics that the symmetry of a graph is highly related to quantum walk. Secondly, we propose an algorithm based on the continuous-time quantum walk to compute the symmetry of a tree. Our algorithm has better time complexity O(N3) than the current best algorithm. Finally, through testing three types of 10024 trees, we find that the symmetry of a tree can be found with an extremely high efficiency with the help of the continuous-time quantum walk.

关键词: quantum walk, tree, symmetry, automorphism

Abstract: Quantum walk, the quantum counterpart of random walk, is an important model and widely studied to develop new quantum algorithms. This paper studies the relationship between the continuous-time quantum walk and the symmetry of a graph, especially that of a tree. Firstly, we prove in mathematics that the symmetry of a graph is highly related to quantum walk. Secondly, we propose an algorithm based on the continuous-time quantum walk to compute the symmetry of a tree. Our algorithm has better time complexity O(N3) than the current best algorithm. Finally, through testing three types of 10024 trees, we find that the symmetry of a tree can be found with an extremely high efficiency with the help of the continuous-time quantum walk.

Key words: quantum walk, tree, symmetry, automorphism

中图分类号:  (Quantum information)

  • 03.67.-a
02.10.Ox (Combinatorics; graph theory) 89.20.Ff (Computer science and technology) 07.05.Tp (Computer modeling and simulation)