Brǖschweiler量子搜索算法的改进及其实验实现  

Modification of Brüschweiler Quantum Searching Algorithm and Realization by NMR Experiment

作　　者：杨晓冬[1] 魏达秀[1] 罗军[1] 缪希茄[1] 

机构地区：[1]中国科学院武汉物理与数学研究所

出　　处：《原子核物理评论》2002年第2期275-277,共3页Nuclear Physics Review

基　　金：国家自然科学基金资助项目 ( 199740 6 4)~~

摘　　要：量子计算与经典计算相比 ,能够极大地提高运算速度 ,解决一些经典计算不能解决或很难解决的问题 .对于在无序数据库中进行搜索这类问题 ,可以用量子算法 ,如Br櫣ｓｃｈｗｅｉｌｅｒ量子搜索算法来解决 .与经典算法相比 ,Br櫣ｓｃｈｗｅｉｌｅｒ量子算法能够指数次地提高搜索速度 .在Br櫣ｓｃｈｗｅｉｌｅｒ提出的算法中 ,数据量子位和观测量子位 (辅助量子位 )是分开的 ,属于不同的量子位 .通过研究 ,对Br櫣ｓｃｈｗｅｉｌｅｒ算法作了改进 ,使之不需要用辅助量子位 ,就可以达到指数次提高搜索速度的目的 .改进后的Br櫣ｓｃｈｗｅｉｌｅｒ量子算法有利于简化实验的设计和实现过程 .同时还利用核磁共振实验 ,演示了改进后的Br櫣ｓｃｈｗｅｉｌｅｒ量子算法的实现 .In recent years, quantum computing research has made big progress, which exploit quantum mechanical laws, such as interference, superposition and parallelism, to perform computing tasks. The most inducing thing is that the quantum computing can provide large rise to the speedup in quantum algorithm. Quantum computing can solve some problems, which are impossible or difficult for the classical computing. The problem of searching for a specific item in an unsorted database can be solved with certain quantum algorithm, for example, Grover quantum algorithm and Brüschweiler quantum algorithm. The former gives a quadratic speedup, and the latter gives an exponential speedup comparing with the corresponding classical algorithm. In Brüschweiler quantum searching algorithm, the data qubit and the read-out qubit (the ancilla qubit) are different qubits. We have studied Brüschweiler algorithm and proposed a modified version, in which no ancilla qubit is needed to reach exponential speedup in the searching, the data and the read-out qubit are the same qubits. The modified Brüschweiler algorithm can be easier to design and realize. We also demonstrate the modified Brüschweiler algorithm in a 3-qubit molecular system by Nuclear Magnetic Resonance (NMR) experiment.

关 键 词：量子搜索算法 Brueschweiler算法 量子计算 核磁共振 量子计算机 实验研究 量子位 

分 类 号：O413[理学—理论物理] O482.532[理学—物理]