Quantum computers can search arbitrarily large databases by a single query
Quantum Physics
2009-10-30 v3
Abstract
This paper shows that a quantum mechanical algorithm that can query information relating to multiple items of the database, can search a database in a single query (a query is defined as any question to the database to which the database has to return a (YES/NO) answer). A classical algorithm will be limited to the information theoretic bound of at least O(log N) queries (which it would achieve by using a binary search).
Cite
@article{arxiv.quant-ph/9706005,
title = {Quantum computers can search arbitrarily large databases by a single query},
author = {Lov K. Grover},
journal= {arXiv preprint arXiv:quant-ph/9706005},
year = {2009}
}
Comments
Several enhancements to the original paper