Grover算法的非定域实现

用核磁共振技术目前只能做到对7个量子比特的演示计算。为此有人提出"分布式量子计算机"的方案。该文考察Grover搜索算法非定域实现,分析为实现这种非定域操作所需的Einstein-Podolsky-Rosen(EPR)纠缠对资源。以2个量子比特为例,说明非定域实现Grover搜索的全过程,并推广到N个量子比特情况下非定域实现的资源需求情况。N为要搜索数据库的大小。结果表明,某些情况下,非定域Grover算法耗用比经典Grover算法更多个EPR对,甚至比经典计算机所用的资源还多,此时的非定域量子计算失去了量子计算的优势。

Nonlocal implementation of the Grover algorithm

At present, state-of-the-art quantum computers using nuclear magnetic resonance (NMR) can only implement 7-qubits. Therefore, some authors have proposed a "distributed quantum computer" that can integrate more qubits. The nonlocal implementation of the Grover quantum search algorithm was used to analyze the Einstein-Podolsky-Rosen (EPR) pair resources required for the nonlocal implementation. This study describes the details of the implementation in a two-qubit system and the nonlocal implementation of a system with N-qubit numbers. N is the databank size to be searched. The results show that for uncertain circumstances, the required resources in a nonlocal quantum computation are more EPR pairs than in a classical Grover algorithm, even more than in a classical computation; hence, the nonlocal implementation of quantum computation loses its advantage.