Classical Communication Cost and Remote Preparation of the Two-Atom Maximally Entangled State

We present a protocol for probabilistic remote preparation of the two-atom maximally entangled state using a four-atom GHZ entangled state as the quantum channel. The two-atom maximally entangled state can be successfully prepared between two distant parties with a success probability of 100%. The successful total probability and classical communication cost are calculated.     

概率远程制备多粒子GHZ纠缠态

利用一个(N 1)粒子部分纠缠Greenberger-Home-Zeilinger(GHZ)态作为量子通道,提出了概率远程制备N粒子GHZ态的两个方案.我们考虑了怎样远程制备一个任意的GHZ态,即两个参数α和β都是复数的情况.此外,计算了远程制备总的成功概率和需要的经典信息量.     

远程制备三粒子纠缠态

在这篇文章中,主要介绍了用三对最大的和非最大两粒子纠缠态作为量子通道远程制备一个三粒子纠缠态的方案。具体方法与量子隐形传态不同的一点就是：我们事先假定Alice已经知道待被制备的态,而Bob并不知道。然后再通过一系列操作得到我们想要制备的态。最后我们得到一个结论：用远程态制备比量子隐形传态更加节省了经典资源。     

远程制备双原子纠缠态

提出一种远程制备双原子纠缠态的方案,该方案基于两个原子与单模腔场的同时非共振相互作用.由于双粒子纠缠态比三粒子纠缠态容易制备,方案用两对双原子纠缠态作为量子通道.Alice 拥有的两个相同原子同时与一单模腔场非共振相互作用.Alice已知她要制备的纠缠态,她选择适当的相互作用时间、测量她所拥有的两个原子并通过经典通道通知Bob.Bob引入一个相同的辅助原子和一个单模腔场来实现方案.方案对腔场状态和腔损耗不敏感,基于当前的腔QED 技术,方案能在实验上实现.该方案有望在量子信息过程中有重要的应用价值.     

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.     

Two Schemes for Probabilistic Remote Preparation of a Four-Particle Entangled Cluster-Type State

Using partial entangled states as the quantum channel, two schemes for probabilistic remote preparation of the four-particle cluster-type state with real and complex coefficients are presented. In the first scheme, the sender and the receiver share two partial Bell states and one partial three-qubit GHZ stats as the quantum channel, and the sender can help a remote receiver to prepare a four-particle entangled cluster-type state by using three-qubit projective measurements with certain probability. In the second scheme, the quantum channel is composed of two partial three-qubit GHZ states, the remote state preparation （RSP） can be successfully realized via the positive operator valued measure （POVM）, and the two-particle projective measurements are also needed in this process. The total success probability and classical communication cost are calculated.     

Two-Step Deterministic Remote Preparation of an Arbitrary Quantum State

We present a two-step deterministic remote state preparation protocol for an arbitrary qubit with the aid of a three-particle Greenberger-Horne-Zeilinger state. Generalization of this protocol for higher-dimensional Hilbert space systems among three parties is also given. We show that only single-particle yon Neumann measurements, local operations, and classical communication are necessary. Moreover, since the overall information of the quantum state can be divided into two different pieces, which may be at different locations, this protocol may be useful in the quantum information field.     

Influence of Noises on Remote State Preparation Using GHZ State

Using a quantum channel consisting of a GHZ state exposed to noisy environment, we investigate how to remotely prepare an entangled state and a qubit state, respectively. By solving the master equation in the Lindblad form, the influence of the various types of noises on the GHZ state is first discussed. Then we use the fidelity to describe how close the remotely prepared state and the initial state are. Our results show that the fidelity is a function of the decoherence rates and the angles of the initial state. It is found that for each of the two RSP schemes, the influence of the noise acting simultaneously in x, y, and z directions on the average fidelity is the strongest while the influence of the noise acting in x or z direction on the average fidelity is relatively weaker.     

Controlled Remote Preparation of a Two-Qubit State via an Asymmetric Quantum Channel

I present a new scheme for probabilistic remote preparation of a general two-qubit state from a sender to either of two receivers. The quantum channel is composed of a partial entangled tripartite Greenberger-Horne-Zeilinger (GHZ) state and a W-type state. I try to realize the remote two-qubit preparation by using the usual projective measurement and the method of positive operator-valued measure, respectively. The corresponding success probabilities of the scheme with different methods as well as the total classical communicationcost required in this scheme are also calculated.     

Two-Step Deterministic Remote Preparation of an Arbitrary Quantum State

We present a two-step deterministic remote state preparation protocol for an arbitrary qubit with the aid of a three-particle Greenberger-Horne-Zeilinger state. Generalization of this protocol for higher-dimensional Hilbert space systems among three parties is also given. We show that only single-particle von Neumann measurements, local operations, and classical communication are necessary. Moreover, since the overall information of the quantum state can be divided into two different pieces, which may be at different locations, this protocol may be useful in the quantum information field.     

Influence of Noises on Remote State Preparation Using GHZ State

Using a quantum channel consisting of a GHZ state exposed to noisy environment, we investigate how to remotely prepare an entangled state and a qubit state, respectively. By solving the master equation in the Lindblad form, the influence of the various types of noises on the GHZ state is first discussed. Then we use the fidelity to describe how close the remotely prepared state and the initial state are. Our results show that the fidelity is a function of the decoherence rates and the angles of the initial state. It is found that for each of the two RSP schemes, the influence of the noise acting simultaneously in x, y, and z directions on the average fidelity is the strongest while the influence of the noise acting in x or z direction on the average fidelity is relatively weaker.     

三量子比特纠缠Greenberger-Horne-Zeilinger态和W态的量子线路实现

两个简单的量子线路被提出分别用来制备三量子比特Greenberger-Horne-Zeilinger(GHZ)态和W态。众所周知,任意的多量子比特门都可以由受控非门和单量子比特门复合而成。同样,我们发现三量子比特GHZ态和W态也可以由受控非门和单量子比特门来制备。因此,从量子计算的角度来看我们的方案十分重要。由于在整个过程只用到了单量子比特操作和双量子比特操作,所以我们的方案在实验中很容易实现。     

Continuous Variable Remote State Preparation with a Two-Mode Squeezed Vacuum State

Continuous variable remote state preparation is presented using a two-mode squeezed vacuum state based on the Heisenberg representation. We show that it is possible to remotely prepare this state in principle. Our scheme’s main advantages are: (i) It is practical, because a two-mode squeezed vacuum state is easy achieved in experiment, and our scheme only requires a beam splitter and a feedforward; (ii) Using our scheme decoherence and being cheating can be avoided.     

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.     

用Greenberger-Horne-Zeilinger态作量子信道实现多点控制的远程单比特幺正变换

提出了一个用三粒子纠缠的GHZ态作为量子信道实现多点控制的远程单比特幺正变换的操纵方案.在该方案中,发送者Alice能“传送”一个幺正变换给远距离的接收者Bob,此幺正变换的结构分别由Alice和Bob决定.而Alice与Bob间的量子信道宽度,亦远程单比特幺正变换的成功操纵几率则由第三者Cindy控制.Cindy与Alice（Bob）间的经典通讯也由Cindy控制.     

基于Cluster态和Bell态的任意三粒子态远程制备

本文提出了一个新颖的基于四粒子cluster态和Bell态制备任意三粒子远程制备方案.在发送者(Alice)对自己手中的粒子做正交完备测量,接受者(Bob)对自己手中的粒子做适当的幺正变换后,任意三粒子远程制备成功.对于Alice的两种不同的正交完备基测量的情况,分别计算了远程制备成功的概率.另外,本方案成功制备的概率在一般情况和一些特殊情况下是可以计算的.分析结果表明:在一般情况下,远程态制备可以以1/8的概率实现;但在一些特殊情况下,成功的概率可以提高到1/4、1/2,甚至1.     

基于Cluster态和Bell态的任意三粒子态远程制备(英文)

本文提出了一个新颖的基于四粒子cluster态和Bell态制备任意三粒子远程制备方案.在发送者(Alice)对自己手中的粒子做正交完备测量,接受者(Bob)对自己手中的粒子做适当的幺正变换后,任意三粒子远程制备成功.对于Alice的两种不同的正交完备基测量的情况,分别计算了远程制备成功的概率.另外,本方案成功制备的概率在一般情况和一些特殊情况下是可以计算的.分析结果表明:在一般情况下,远程态制备可以以1/8的概率实现;但在一些特殊情况下,成功的概率可以提高到1/4、1/2,甚至1.     

Probabilistic Remote Preparation of a Tripartite High-Dimensional Equatorial Entangled State

We present a scheme for probabilistic remote preparation of a tripartite qutrit entangled state with a partial tripartite qutrit entangled state and a partial bipartite qutrit entangled state as the quantum channel. It is found that a bipartite qutrit orthogonal projective measurement, an auxiliary qutrit particle, and the corresponding unitary transformation are required. A scheme for probabilistic remote preparation of a tripartite qudit equatorial entangled state by using a partial tripartite qudit entangled state and a partial bipartite qudit entangled state as the quantum channel is also proposed. We calculate the successful total probability and the total classical communication cost required in the RSP process, respectively.     

Remote Preparation of Multipartite Equatorial Entangled States in High Dimensions with Three Parties

A scheme for probabilistic remotely preparing N-particle d-dimensional equatorial entangled states via entangled swapping with three parties is presented. The quantum channel is composed of N - 1 pairs of bipartite d-dimensional non-maximally entangled states and a tripartite d-dimension non-maximally entangled state. It is shown that the sender can help either of the two receivers to remotely prepare the original state, and the N-particle projective measurement and the generalized Hadamard transformation are needed in this scheme. The total success probability and classical communication cost are calculated.     

利用纠缠交换在理想和非理想条件下的远程态制备

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.