分离状态下的有效纠缠分配(英文)  

Efficient Entanglement Distribution by Separable States

作　　者：蔡虹[1,2] 陈炯[1] 

机构地区：[1]山西职业技术学院,太原030006 [2]山西大学物理电子工程学院,太原030006

出　　处：《光子学报》2011年第4期622-626,共5页Acta Photonica Sinica

基　　金：The National High Technology Research and Development Programof China(No.2009AA063006)

摘　　要：提出采用两个量子比特(四维空间的qudit)作为分离的中间媒介实现高效的纠缠分发方案。首先,两个中间媒介量子比特与两个不同站点的量子比特(定义为a和b)形成四个量子比特非锁定束缚纠缠态,也称为Smolin态.然后,对两个附属量子比特在贝尔基矢上进行联合投影测量,测量结果传送给a和b,基于测量结果,量子比特a和b将可以转换为EPR纠缠态.在整个过程,两个附属量子比特始终与量子比特a和b保持分离.该方案提供了一种利用分离态实现最大纠缠态分发的高效方法,并且给出了公式来描述和理解该过程.An effcient entanglement distribution protocol was proposed using a qudit（4-dimensional space） as a separable mediating ancilla.Two qubits were used to describe a qudit in order to simplify the description.Firstly,both of the two ancilla qubits and the two distant qubits（a and b） were formed into a four-qubit unlockable bound entangled state,called the Smolin state.Then,a projective measurement in the Bell basis was performed on the two ancilla qubits and the measurement results was delivered to a and b.Based on the measurement results,the qubits a and b can be converted into a standard singlet state locally.At any stage of the protocol,the two ancilla qubits was always separable from the subsystem（a and b）.This scheme provides an effective way to distribute the maximally entangled states by separable states,and presents a concise formalism to describe and understand this physical process.

关 键 词：纠缠 中间媒介 联合测量 

分 类 号：O433.2[机械工程—光学工程]