How fast can a quantum computer search?
量子物理
2007-05-23 v3
摘要
This paper gives a simple proof of why a quantum computer, despite being in all possible states simultaneously, needs at least 0.707 sqrt(N) queries to retrieve a desired item from an unsorted list of items. The proof is refined to show that a quantum computer would need at least 0.785 sqrt(N) queries. The quantum search algorithm needs precisely this many queries.
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)