量子计算机能搜索多快？
量子物理
2007-05-23 v3
摘要
本文给出简洁证明：为何量子计算机虽同时处于所有可能状态，仍至少需要 0.707 sqrt(N) 次查询才能从无序列表中检索出所需项。证明被精炼以表明量子计算机至少需要 0.785 sqrt(N) 次查询。量子搜索算法恰需如此多次查询。
引用
@article{arxiv.quant-ph/9809029,
title = {How fast can a quantum computer search?},
author = {Lov K. Grover},
journal= {arXiv preprint arXiv:quant-ph/9809029},
year = {2007}
}
备注
Postscript, 7 pages. This proof tries to give a simple argument why the search algorithm is optimal (This paper was originally put out on quant-ph on September 9, 1998, the present version has several important improvements)