Bohmian mechanics Grover's algorithm NP-complete algorithm quantum computer computer P
Theorists have considered a hypothetical generalization of a standard quantum computer that could access the histories of the hidden variables in Bohmian mechanics. (Such a computer is completely hypothetical and would not be a standard quantum computer, or even possible under the standard theory of quantum mechanics.) Such a hypothetical computer could implement a search of an N-item database at most in 



O
(


N

3



)


{\displaystyle O({\sqrt[{3}]{N}})}

 steps. This is slightly faster than the 



O
(


N


)


{\displaystyle O({\sqrt {N}})}

 steps taken by Grover's algorithm. Neither search method would allow either model of quantum computer to solve NP-complete problems in polynomial time.
