Scheme for Implementing Quantum Search Algorithm in a Cluster State Quantum Computer.pdf

维普资讯 Commun．Theor．Phys．(Beijing，China)49(2008)PP．1487-1490 ⑥ ChinesePhysicalSociety Vo1．49，No．6，June15，2008 SchemeforImplementingQuantum SearchAlgorithm inaClusterStateQuantum Computer WANG Yan—Hui，andZHANG Yong DepartmentofPhysics，HunanUniversityofScienceandTechnology,Xiangtan411201，China KeyLaboratoryforQuantum InformationandMeasurementsandDepartmentofPhysics，TsinghuaUniversity,Beijing 100084，China (ReceivedJune12，20071 Abstract Usingclusterstateandsinglequbitmeasurementonecanper~rm theone-wayquantum computation．Here we舀veadetailedschemeofrrealizingamodifiedGroversearchalgorithm usingmeasurementsonclusterstate．Wegive themeasurementpattern ofrthecluster-staterealization ofthealgorithm and estimated thenum berofmeasurement neededforitsimplementation．Itisfoundthat0(23n／2n。、numberofsing1equbitmeasurementsisrequiredf01rjts realization in acluster-statequna tum computer． PACS numbers：03．67．Dd，03．67．Hk K eyw ords：clusterstate，longalgorithm ，control—phasegate，measurementpattern Clusterstatequantumcomputation(QCc1usesagiven Grover’squantum search algorithm[4Jis an impor— entangledstatenamedclusterstateasitscentralphysical tantdevelopment inquantum computation．Itachieves resource．Itisexpectedthatclusterstatescanbecreated square—rootspeedup overclassicalalgorithmsinunsorted efficientlyinsystemswithanIsing—typeinteractionatvery databasesearching． Ithasextensiveapplications，many low temperaturesinalatticeconfiguration．l【JItishighly problems，including thedeciphering ofDES encryption ， entangledandismaximallyconnected．meanwhileitsper— scheme．can be reduced to it．_5Jand itcan beused to