Grover’s quantum searching algorithm is optimal
Phys. Rev. A 60, 2746 – Published 1 October, 1999
DOI: https://doi.org/10.1103/PhysRevA.60.2746
Abstract
I show that for any number of oracle lookups up to about Grover’s quantum searching algorithm gives the maximal possible probability of finding the desired element. I explain why this is also true for quantum algorithms which use measurements during the computation. I also show that unfortunately quantum searching cannot be parallelized better than by assigning different parts of the search space to independent quantum computers.