Grover量子搜索算法解决了未加排序的数据库搜索问题,在2n个元素中搜索M个目标元素,其计算复杂度为O(√2^n/M),相对于经典算法实现了二次加速,但是,当目标元素个数接近2^n/2时该算法成功率只达到50%。从任意相位的Grover变换从发.给出一种改进的多目标元素量子搜索算法,该算法在目标元素个数肘≥2^n/4时,只用一次Gmver变换就能以概率1完成搜索。
Grover's quantum mechanical search algorithm solves the unsorted database search with quadratic speed-up over the classical algorithms.But Grover's algorithm will be inefficient when the number of matching is close to 2^n/2.This paper presents a quantum algorithm which can get a target item with certainty by a single query when the number of the target items is more than a quarter.