Reestablishment of an Unknown State and Its Orthogonal Complement State with Assistance

In this paper, we propose a protocol where one can realize reestablishment of an unknown state and its orthogonal complement state with a certain probability. In the first stage of the protocol, teleportation is performed between Alice (a sender) and Bob (a receiver) through a nonmaximally entangled quantum channel. In the process of teleportation, Alice performs nonmaximally entangled state measurement. In the second stage of the protocol, Victor(a state preparer) disentangles leftover nonmaximally entangled states by a single-particle measurement. With the assistance of Victor Alice can reestablish the original state or produce its orthogonal state.     

Reestablishment of an Unknown State and Its Orthogonal Complement State with Assistance

In this paper, we propose a protocol where one can realize reestablishment of an unknown state and its orthogonal complement state with a certain probability. In the first stage of the protocol, teleportation is performed between Alice (a sender) and Bob (a receiver) through a nonmaximally entangled quantum channel. In the process of teleportation, Alice performs nonmaximally entangled state measurement. In the second stage of the protocol, Victor (a state preparer) disentangles leftover nonmaximally entangled states by a single-particle measurement. With the assistance of Victor Alice can reestablish the original state or produce its orthogonal state.     

三粒子纠缠Ｗ态的隐形传态

提出利用三个二粒子纠缠态作为量子信道，实现三粒子纠缠Ｗ态的隐形传态的方案.首先考察量子信道是最大纠缠态的情形，然后进一步考察量子信道是非最大纠缠态的情形.发现在量子信道为非最大纠缠态时，通过引进一个辅助粒子，并构造一个幺正变换矩阵，即可以一定的概率完成三粒子纠缠Ｗ态的隐形传态. 关键词： 隐形传态 三粒子纠缠 纠缠Ｗ态 非最大纠缠量子信道     

Teleportation of a Bipartite Entangled Coherent State via a Four-Partite Cluster-Type Entangled State

We present an optical scheme to almost completely teleport a bipartite entangled coherent state using a four-partite cluster-type entangled coherent state as quantum channel. The scheme is based on optical elements such as beam splitters, phase shifters, and photon detectors. We also obtain the average fidelity of the teleportation process. It is shown that the average fidelity is quite close to unity if the mean photon number of the coherent stateis not too small.     

Probabilistic Teleportation of an Arbitrary Two-Atom State in Cavity QED

We propose a scheme for the teleportation of an arbitrary two-atom state by using two pairs of two-atom nonmaximally entangled states as the quantum channel in cavity QED. It is Shown that no matter whether the arbitrary two-atom pure state to be teleported is entangled or not, our teleportation scheme can always be probabilistically realized. The success prohability of teleportation is determined by the smaller coemcients of the two initially entangled atom pairs.     

Teleportation of Entangled States through Divorce of Entangled Pair Mediated by a Weak Coherent Field in a High-Q Cavity

We propose a scheme to partially teleport an unknown entangled atomic state. A high-Q cavity, supporting one mode of a weak coherent state, is needed to accomplish this process. By partial teleportation we mean that teleportation will occur by changing one of the partners of the entangled state to be teleported. The entangled state to be teleported is composed by one pair of particles, we called this surprising characteristic of maintaining the entanglement, even when one of the particle of the entangled pair being teleported is changed, of divorce of entangled states.     

Probabilistic teleportation of an unknown N-atom state using a two-atom nonmaximally entangled state in cavity QED

We present a scheme for realizing probabilistic teleportation of an unknown N-atom state via cavity QED. This scheme requires only a nonmaximally entangled pair to be used as a quantum channel, so the requirement of entanglement is reduced. In addition, our scheme does not involve the Bell-state measurement and is insensitive to the cavity decay, which is important from the experimental point of view. If the quantum channel is a two-atom maximally entangled state, teleportation of an unknown N-atom state can be realized by a simpler scheme via cavity QED.     

Probabilistic Teleportation of a Four-Particle Entangled State

A Scheme for teleporting an unknown four-particle entangled state is proposed via entangled swapping. In this scheme, four pairs of entangled particles are used as quantum channel. It is shown that, if the four pairs of particles are nonmaximally entangled, the teleportation can be successfully realized with certain probability if a receiver adopts some appropriate unitary transformations.     

三粒子纠缠相干态的隐形传态

提出了一个利用一个两粒子最大纠缠相干态和一个三粒子纠缠相干态作为量子信道进行三粒子纠缠相干态隐形传态的方案.该方案只需线性光学操作和双模光子数测量.计算结果表明,应用本方案的设置,隐形传态成功的概率与所用的相干态的平均光子数有关,反映了纠缠相干态的非正交特性.     

Multiparty-controlled teleportation of an arbitrary GHZ-class state by using a d-dimensional (N+2)-particle nonmaximally entangled state as the quantum channel

We present a scheme for multiparty-controlled teleportation of an arbitrary high-dimensional GHZ-class state with a d-dimensional (N+2)-particle GHZ state following some ideas from the teleportation (Chinese Physics B, 2007, 16: 2867). This scheme has the advantage of transmitting much fewer particles for controlled teleportation of an arbitrary multiparticle GHZ-class state. Moreover,we discuss the application of this scheme by using a nonmaximally entangled state as its quantum channel.     

Teleportation of a three—particle entangled W state

We have investigated the problem of teleporting a three-particle entangled W state and we propose a scheme based on entanglement spapping to complete the teleportation.We also put forward a scheme for the teleportation of a general W state by using nonmaximally entangled quantum channels.The probability of success of the latter scheme is obtained.     

A Scheme for Teleportation of an Unknown Entangled Coherent State via Raman Interaction

A scheme is reported for the teleportation of entangled coherent states through the degenerate Raman interaction.The scheme uses an entangled state of an atom and two coherent states as a quantum channel.It makes full use of coherent cavity fields.Furthermore,it does not need any classical field to transform the atom states.     

Nonmaximally entangled states can be better for multiple linear optical teleportation

We investigate multiple linear optical teleportation in the Knill-Laflamme-Milburn scheme with both maximally and nonmaximally entangled states. We show that if the qubit is teleported several times via a nonmaximally entangled state, then the errors introduced in the previous teleportations can be corrected by the errors introduced in the following teleportations. This effect is so strong that it leads to another interesting phenomenon: i.e., the total probability of successful multiple linear optical teleportation is higher for nonmaximally entangled states than maximally entangled states.     

Application of Bipartite and Tripartite Entangled State Representations in Quantum Teleportation of Continuous Variables

We mostly investigate two schemes. One is to teleport a multi-mode W-type entangled coherent state using a peculiar bipartite entangled state as the quantum channel different from other proposals. Based on our formalism,teleporting multi-mode coherent state or squeezed state is also possible. Another is that the tripartite entangled state is used as the quantum channel of controlled teleportation of an arbitrary and unknown continuous variable in the case of three participators.     

Application of Bipartite and Tripartite Entangled State Representations in Quantum Teleportation of Continuous Variables

We mostly investigate two schemes. One is to teleport a multi-mode W-type entangled coherent state using a peculiar bipartite entangled state as the quantum channel different from other proposals. Based on our formalism,teleporting multi-mode coherent state or squeezed state is also possible. Another is that the tripartite entangled state is used as the quantum channel of controlled teleportation of an arbitrary and unknown continuous variable in the case of three participators.     

Universal teleportation with a twist

We give a transfer theorem for teleportation based on twisting the entanglement measurement. This allows one to say what local unitary operation must be performed to complete the teleportation in any situation, generalizing the scheme to include overcomplete measurements, non-Abelian groups of local unitary operations (e.g., angular momentum teleportation), and the effect of nonmaximally entangled resources.     

基于(2m+1)粒子纠缠态的任意m粒子态量子可控离物传态(英文)

提出了一个基于高维2m+1粒子纠缠态的任意m粒子态量子可控离物传态方案,发送方Alice对需传送的未知态量子系统和手中的纠缠粒子执行m个广义Bell基测量,控制方执行广义X基测量,依据预先共享量子纠缠态非定域相关性,接收方对手中的粒子执行相应的幺正操作就可以重建原来未知量子态.与其他方案相比,方案减少了任意高维多粒子态可控离物传送所需传送粒子数.我们进一步讨论了基于纯纠缠信道的概率量子可控离物传态方案,通过与发送方和控制方合作,接收方只需对手中的纠缠粒子和引入的附加粒子执行联合幺正演化和投影测量,就可以在他的粒子上概率的重建原来的未知量子态,最后,方案计算讨论了基于纯纠缠态量子可控离物传态成功概率与信道纠缠度之间的关系.     

Scheme for Realizing Probabilistic Teleportation of Bipartite Atomic State via Cavity QED

We present a physical scheme for realizing probabilistic teleportation of bipartite atomic states via cavity QED. This scheme requires only a nonmaximally entangled pair used as quantum channel, so we reduce the requirement of entanglement.     

Statistical properties of coherent photon-subtracted two-mode squeezed vacuum and its application in quantum teleportation

We introduce a kind of non-Gaussian entangled state, which can be obtained by operating a non-local coherent photon-subtraction operation on a two-mode squeezed vacuum. It is found that its normalization factor is only related to the Legendre polynomials, which is a compact expression. Its statistical properties are discussed by the negative region Wigner function with the analytical expression. As an application, the quantum teleportation for coherent states is considered by using the non-Gaussian state as an entangled channel. It is found that the teleportation fidelity can be enhanced by this non-Gaussian operation.     

Scheme for Entanglement Concentration of Unknown Multiparticle Greenberger-Horne-Zeilinger or W Class States

We present two schemes for concentrating unknown nonmaximally entangled Greenberger-Horme-Zeilinger (GHZ) or W class states. The first scheme for concentrating the nonmaximally entangled GHZ state is based on linear optical devices. The second scheme for concentrating the W class states can be applied to a wide variety of atomic state. Both of our schemes are not postselection ones and are within the current technologies.