一种用于数据库搜索的快速量子力学算法
量子物理
2008-02-03 v3
摘要
设想一个包含 N 个姓名、完全随机排列的电话簿。要以 50% 的概率找到某人的电话号码，任何经典算法（无论确定性的还是概率性的）都至少需要查看 N/2 个姓名。量子力学系统可处于态的叠加并同时核查多个姓名。通过适当调节各操作的相位，成功的计算相互增强，而其余的则随机干涉。结果，所需的电话号码仅需 O(sqrt(N)) 步即可获得。该算法在小的常数因子范围内是最快的可能量子力学算法。
引用
@article{arxiv.quant-ph/9605043,
title = {A fast quantum mechanical algorithm for database search},
author = {Lov K. Grover},
journal= {arXiv preprint arXiv:quant-ph/9605043},
year = {2008}
}
备注
8 pages, single postscript file. This is an updated version of a paper that was originally presented at STOC 1996. The algorithm is the same; however, the proof has been simplified by using a new interpretation termed "inversion about average." Also a few recently discovered insights have been added. Journal Ref.: Proceedings, 28th Annual ACM Symposium on the Theory of Computing (STOC), May 1996, pages 212-219