Abstract

Inspired by the Elitzur-Vaidman bomb testing problem [arXiv:hep-th/9305002], we introduce a new query complexity model, which we call bomb query complexity B(f). We investigate its relationship with the usual quantum query complexity Q(f), and show that B(f)=\Theta(Q(f)ˆ2). This result gives a new method to upper bound the quantum query complexity: we give a method of finding bomb query algorithms from classical algorithms, which then provide nonconstructive upper bounds on Q(f)=\Theta(\sqrtB(f)). We subsequently were able to give explicit quantum algorithms matching our upper bound method. We apply this method on the single-source shortest paths problem on unweighted graphs, obtaining an algorithm with O(nˆ1.5) quantum query complexity, improving the best known algorithm of O(nˆ1.5\sqrtłog n) [arXiv:quant-ph/0606127]. Applying this method to the maximum bipartite matching problem gives an O(nˆ1.75) algorithm, improving the best known trivial O(nˆ2) upper bound.

Publication Details
Publication Type
Journal Article
Year of Publication
2016
Volume
12
Number of Pages
1–35
DOI
10.4086/toc.2016.v012a018
URL
http://theoryofcomputing.org/articles/v012a018/
Journal
Theory of Computing
Contributors
Groups
Date Published
11/2016