Time-bin-encoding-based remote states generation of nitrogen-vacancy centers through noisy channels

We design proposals to generate a remote Greenberger-Horne-Zeilinger(GHZ) state and a W state of nitrogenvacancy(NV) centers coupled to microtoroidal resonators(MTRs) through noisy channels by utilizing time-bin encoding processes and fast-optical-switch-based polarization rotation operations.The polarization and phase noise induced by noisy channels generally affect the time of state generation but not its success probability and fidelity.Besides,the above proposals can be generalized to n-qubit between two or among n remote nodes with success probability unity under ideal conditions.Furthennore,the proposals are robust for regular noise-changeable channels for the n-node case.This method is also useful in other remote quantum information processing tasks through noisy channels.     

辫子Hopf代数的积分

本文引进了无限维辫子Hopf代数日的忠实拟对偶H~d和严格拟对偶H~(d′)．证明了每个严格拟对偶H~(d′)是一个H-Hopf模．发现了H~d的极大有理H~d-子模H~(drat)与积分的关系,即：H~(drat)≌∫_(H~d)~l■H．给出了在Yetter-Drinfeld范畴(_B~ByD,C)中的辫子Hopf代数的积分的存在性和唯—性．     

不同激光脉冲对J-C模型中的反聚束效应的影响

选取三种不同的激光脉冲形式,研究了依赖于时间的J-C模型中的反聚束效应.并对三种不同脉冲形式下所得的结果进行比较.     

Secure Quantum Secret Sharing Based on Reusable GHZ States as Secure Carriers

We show that a potential eavesdropper can eavesdrop whole secret information when the legitimate users use secure carrier to encode and decode classical information repeatedly in the protocol proposed by Bagherinezhad S and Karimipour V [Phys. Rev. A 67（2003）044302]. Then we present a revised quantum secret sharing protocol by using the Greenberger-Horne-Zeilinger state as secure carrier. Our protocol can resist Eve＇s attack.     

Probabilistic remote preparation of a two-atom entangled state

A scheme for remotely preparing a two-atom entangled state via entanglement swapping in cavity quantum electronic dynamics （QED） with the help of separate measurements is proposed. And the effect of cavity decay is eliminated in our scheme.     

Generation of the nonlocal quantum entanglement of three three-level particles by local operations

We propose a scheme to realize the nonlocal quantum entanglement of three three-level particles by using a three-particle entangled state of three levels as a quantum channel with the aid of some local unitary transformations. This scheme can be directly generalized to the nonlocal quantum entanglement of N three-level particles.     

Implementation of unambiguous comparison for unknown pure quantum states with cavity-assisted interaction

We propose two effective schemes for local and remote unknown atomic state comparisons with a cavity-assisted single photon input-output process without any initial entanglement or auxiliary resource. The unambiguous state discrimination is considered using the state comparison process as the basic module. All the implementation schemes here just involve common quantum logic gates and the single qubit measurement. The analysis shows that our schemes are feasible under the current experimental conditions.     

Two-qubit and three-qubit controlled gates with cross-Kerr nonlinearity

Schemes for two-qubit and three-qubit controlled gates based on cross-Kerr nonlinearity are proposed in this paper.The probability of the success of these gates can be increased by quantum nondemolition detectors,which are used to judge which paths the signal photons pass through.These schemes are almost deterministic and require no ancilla photon.The advantages of these gates over the existing ones include less resource consumption and a higher probability of success,which make our schemes more feasible with current technology.     

Implementation of positive-operator-value measurements for single spin qubit via Heisenberg model

This paper shows that a proposal for implementing all possible two-operator positive-operator-value measurements of single spin qubit can be obtained via introducing another spin qubit as ancilla. The realization process is accomplished from the free evolution of the Heisenberg XX model by considering nearest-neighbour spin interaction. A controlled-NOT gate, which is a significant operator for this scheme is also constructed and the generalisation to multiple-operator is considered finally.     

与非等同双原子相互作用下光场的相干性质

研究了具有不同偶极矩的两个原子与双模压缩真空场相互作用系统中光场的相干性质.讨论了两个原子与双模压缩真空场的相对耦合常量(R=g1/g2)和光场的初始压缩因子r对二阶相干度、光场的模间相关性、Cauchy-Schwartz不等式的影响.结果表明,光场的初始压缩因子较小时,光子的聚束效应和反聚束效应交替出现,且光场的模间相关程度较强.光场的初始压缩因子较大时,光子呈现聚束效应,且模间相关程度较弱.双原子的相对耦合常量R对二阶相干度、光场的模间相关性、Cauchy-Schwartz不等式的时间演化规律有影响,但不能改变光场模间相关的非经典性质.