Multiparticle Generalization of Remote State Preparation

We present a scheme for preparing remotely a three-particle pure entangled state via entanglement swapping,and then we directly generalize it to the multiparticle case. It is shown that by using N pairs of bipartite EPR states as the quantum channel, remote preparation of some specially chosen N-particle pure entangled states can be achieved faithfully with an N-particle orthonormal basis measurement and only N bits of classical information.     

Multiparticle Generalization of Remote State Preparation

We present a scheme for preparing remotely a three-particle pure entangled state via entanglement swapping,and then we directly generalize it to the multiparticle case. It is shown that by using N pairs of bipartite EPR states as the quantum channel, remote preparation of some specially chosen N-particle pure entangled states can be achieved faithfully with an N-particle orthonormal basis measurement and only N bits of classical information.     

Optimal Conclusive Teleportation of an Arbitrary d-Dimensional N-Particle Unknown State via a Partially Entangled Quantum Channel

In the paper we generalize the standard teleportation to the conclusive teleportation case which can teleportan arbitrary d-dimensional N-particle unknown state via the partially entangled quantum channel. We show that onlyif the quantum channel satisfies a constraint condition can the most general d-dimensional N-particle unknown state beperfect conclusively teleported. We also present a method for optimal conclusively teleportation of the N-particle statesand for constructing the joint POVM which can discern the quantum states on the sender's (Alice's) side. Two typicalexamples are given so that one can see how our method works.     

Remote preparation of a Greenberger--Horne--Zeilinger state via a two-particle entangled state

We present two schemes for realizing the remote preparation of a Greenberger--Horne--Zeilinger (GHZ) state. The first scheme is to remotely prepare a general N-particle GHZ state with two steps. One is to prepare a qubit state by using finite classical bits from sender to receiver via a two-particle entangled state, and the other is that the receiver introduces N - 1 additional particles and performs N - 1 controlled-not (C-Not) operations. The second scheme is to remotely prepare an N-atom GHZ state via a two-atom entangled state in cavity quantum electrodynamics (QED). The two schemes require only a two-particle entangled state used as a quantum channel, so we reduce the requirement for entanglement.     

远程制备多粒子纯态

我们提出了一个远程制备三种形式的多粒子纯态的方案,远程制备一般形式的多粒子纯态及两种特殊情况下的多粒子纯态.首先利用大失谐腔制备出N个原子的纠缠态[14],并将这N个原子分配给Alice和Bob等其他的参与者.然后Alice根据要远程制备的态对她的原子进行相应的单原子投影测量,并且将测量结果以经典信息的方式告诉给其他参与者.其他参与者根据收到的信息决定对自己的原子要么不操作,要么进行特定的操作,来转换他们所共享的纠缠态,最终除Alice以外的参与者就会处于期望的纠缠态.每一种情况下的信息消耗都是很少的,只消耗一量子比特和一经典比特.整个方案都基于现有的腔量子电动力学技术,因此该方案是可行性的.     

Teleportation of N-particle entangled W state via entanglement swapping

A scheme for teleporting an unknown N-particle entangled W state is proposed via entanglement swapping. In this scheme, N maximally entangled particle pairs are used as quantum channel. As a special case, the teleportation of an unknown four-particle entangled W state is studied.     

A new representation and probabilistic teleportation of an arbitrary and unknown N-particle state

A new representation of an arbitrary and unknown N-particle state is presented at first. As an application, a scheme for teleporting an arbitrary and unknown N-particle state is proposed when N pairs of two-particle non- maximally entangled states are utilized as quantum channels. After Alice （sender） makes Bell-state measurement on her particles, Bob （recipient） introduces an auxiliary particle and carries out appropriate unitary transformation on his particle and the auxiliary particle depending on classical information from Alice. Then, von Neumann measurement that confirms whether the teleportation succeeds or not is performed by Bob on the auxiliary particle. In order to complete the teleportation, another N-1 times operations need to be performed which are similar to the above ones. It can be successfully realized with a certain probability which is determined by the product of the smaller coefficients of non-maximally entangled pairs. All possible unitary transformations are given in detail.     

Scheme for Asymmetric and Deterministic Controlled Bidirectional Joint Remote State Preparation

The scheme for asymmetric and deterministic controlled bidirectional joint remote state preparation by using one ten-qubit entangled state as the quantum channel is proposed. In this scheme, Alice and David want to remotely prepare an arbitrary single-qubit state at Bob's site, at the same time, Bob and Eve wish to help Alice remotely prepare an arbitrary two-qubit entangled state. Alice and Bob can simultaneously prepare the desired states with the cooperation of David and Eve under the control of Charlie.     

Probabilistic Remote Preparation of a Three-Particle Entangled State via Two Different Non-maximally Entangled Channels

We present two schemes for preparing remotely a three-particle entangled state by two different quantum channels. In the first scheme, two partial three-particle entangled states are used as the quantum channels, while in the second scheme, three two-particle non-maximally entangled states are employed as the quantum channels. It is shown that the remote state preparation can be successfully realized with certain probability, for both two schemes, if a sender performs some projective measurements and a receiver adopts some appropriate unitary transformations. It is shown also that the successful probabilities of these two schemes are different.     

Probabilistic Remote Preparation of a Three-Particle Entangled State via Two Different Non-maximally Entangled Channels

We present two schemes for preparing remotely a three-particle entangled state by two different quantum channels. In the first scheme, two partial three-particle entangled states are used as the quantum channels, while in the second scheme, three two-particle non-maximally entangled states are employed as the quantum channels. It is shown that the remote state preparation can be successfully realized with certain probability, for both two schemes, if a sender performs some projective measurements and a receiver adopts some appropriate unitary transformations. It is shown also that the successful probabilities of these two schemes are different.     

用两粒子纠缠对进行{\bf\large{N}}粒子纠缠态的隐形传送

本文提出了一个方案:将三粒子纠缠态从一个发送者传给两个接收者之一,并将其推广到N粒子纠缠态的传送。这里，我们仅用两粒子纠缠对作通道就实现了N粒子纠缠态的传送。此方案相比以往的方案节省了大量纠缠资源，且成功传送的几率达到了1。     

Joint Remote State Preparation of Arbitrary Two- and Three-Particle States

We propose a scheme to joint remotely prepare arbitrary two- and three-particle entangled states by using non-maximally three-particle GHZ state as the quantum channel. Our scheme consists of two senders and one receiver. It will be shown that two senders can help the receiver to remotely prepare the original state with certain probability. The projective measurement and corresponding unitary operation are needed in this article.     

Preparation of arbitrary n-particle d-dimensional superposition states using only single qubit operations and CNOT gates

In this article, using only single qubit operation and a CNOT gate, we propose a scheme for creating arbitrary n-particle d-dimensional superposition states including entangled states and give the relevant circuits for realizing this scheme.     

纠缠相干态的纠缠浓缩

利用线性光学元器件对光场量子态进行操纵,可以实现远程的量子纠缠调控和量子通讯.通过分析光学分束器对相干态光场的作用,发现当初始光场态是两个两部分纠缠态的直乘时,让其中的两模通过光学分束器作用后再对其进行光子计数,另外两模将会塌缩到新的纠缠态.基于这个特点,提出了一个实现部分纠缠相干态纠缠浓缩的方案.在这个方案中,两个部分纠缠相干态被用来作为量子信道,通过光学分束器作用后对光场进行光子数探测时,如果测量到光场的两模分别处于奇光子数态和零光子数态,则光场另外的两模将塌缩到最大纠缠态,从而完成纠缠浓缩的过程.计算结果表明,对于纠缠相干态,无论其初始的纠缠是多么微弱,利用这种方法总有一定的几率可以从中提纯出最大纠缠态.     

Controlled Teleportation of an Arbitrary Multi-Qudit State in a General Form with d-Dimensional Greenberger-Horne-Zeilinger States

A general scheme for controlled teleportation of an arbitrary multi-qudit state with d-dimensional Greenberger- Horne--Zeilinger （GHZ） states is proposed. For an arbitrary m-qudit state, the sender Alice performs m generalized Bell-state projective measurements on her 2m qudits and the controllers need only take some single-particle measurements. The receiver Charlie can reconstruct the unknown m-qudit state by performing some single-qudit unitary operations on her particles if she cooperates with all the controllers. As the quantum channel is a sequence of maximally entangled GHZ states, the intrinsic efticiency for qudits in this scheme approaches 100% in principle.     

利用纠缠交换在理想和非理想条件下的远程态制备(英文)

提出了利用纠缠交换技术实现一个纠缠态的远程制备.考虑在量子信道没有遭受噪声影响的条件下,利用一对两粒子纠缠态作为量子信道去实现远程态制备.此外我们考察了噪声存在时的远程态的制备,研究显示不同类型的量子噪声对远程态制备过程的保真度的影响不同.对一个确定量子态,我们考察了消相干效应对其远程制备的影响.     

Remote Preparation of a Two-Particle Entangled State via Two Tripartite <Emphasis Type="Italic">W</Emphasis> Entangled States

We present a scheme for remotely preparing a general two-particle entangled state via two tripartite W entangled states of different amplitudes. In this scheme one sender and two remote receivers are involved. The sender can help either one of the receivers to remotely reconstruct the original state with the aid of the other receiver’s two single-particle orthogonal measurements. It is shown that by means of the method of the positive operator-valued measurement, our remote state preparation scheme can be achieved probabilistically. This project supported by the National Key Basic Research and Development Program of China under Grant No. 2006CB921604 and the National Natural Science Foundation of China under Grant Nos. 60578050 and 10434060.     

Remote State Preparation of a Two-Atom Entangled State in Cavity QED

A physical scheme for remotely preparing a diatomic entangled state based on the cavity QED technique is presented in this paper. The quantum channel is composed of a two-atom entangled state and a three-atom entangled W state. The non-resonant interaction between two atoms and cavity is utilized at sender’s side to distribute the information among the quantum channel, and the original state can be transmitted to either one of the two receivers. It shows that an extra cavity and an atom are needed at the final receiver’s side as an auxiliary system if the non-maximally entangled states are worked as the quantum channel. The total success probabilities for the two receivers are not equal to each other except that the states of the quantum channel are maximally entangled.     

N粒子量子纠缠态的隐形传送

该文提出了一个利用N对二粒子纠缠态作为量子通道实现N粒子纠缠态的隐形传送的方案.发送者对需传送的N粒子量子态与属于自己的纠缠对中的粒子分别进行N次Bell基测量,并将测量结果通过经典通道告诉接受者,接受者根据这些信息对自己拥有的N个粒子进行相应的联合幺正变换,可使这N个粒子处于待发送的原始量子态,从而实现概率为1的量子态的隐形传送.     

Deterministic Remote Preparation of a Four-Qubit Cluster-Type Entangled State

We propose a scheme for remotely preparing a four-qubit cluster-type state with complex coefficients by using six EPR pairs as the quantum channel. To complete the remote state preparation scheme, a novel set of four-qubit mutually orthogonal basis vectors has been introduced. It is shown that, after the sender performs two different four-qubit projective measurements, the receiver can reconstruct the original state (to be prepared remotely) with unit successful probability. Moreover, the scheme is also generalized to the case that non-maximally two-qubit entangled states are taken as the quantum channel.