Quantum State Sharing of a Single-Qubit State via an Arbitrary High-Dimensional Entangled State

We propose two schemes for quantum state sharing of single-qubit state by using three-qutrit and three-qudit entangled states as quantum channel, respectively. After the sender performs a non-symmetric basis measurement on her particles, and the controller operates a single-particle measurement on his particle, the state receiver can reconstruct the original state of the sender by applying the appropriate unitary operation. The analysis of the security in the schemes has been given.     

Bidirectional Controlled Remote State Preparation of an Arbitrary Two-Qubit State

We propose a scheme of bidirectional controlled remote state preparation of an arbitrary two-qubit state, where a nine-qubit entangled state is used as the quantum channel. In our scheme, Alice and Bob can prepare simultaneously an arbitrary two-qubit state for each other’s place with the help of the controller Charlie. The total success probability for our scheme reaches 100%. PACS numbers 03.67.Hk, 03.65.Ud, 42.50.Dv.

     

Splitting an Arbitrary Three-Qubit State via a Five-Qubit Cluster State and a Bell State

Quantum information splitting (QIS) provides an idea for transmitting the quantum state through a classical channel and a preshared quantum entanglement resource. This paper presents a new scheme for QIS based on a five-qubit cluster state and a Bell state. In this scheme, the sender transmits the unknown three-qubit secret state to two agents by the quantum channel with the Bell basis measurement three times and broadcasts the measurement results to the agents through the classical channel. The agent who restores the secret state can successfully recover the initial information to be transmitted through the appropriate unitary operation with the help of the other party. Firstly, our scheme’s process can be accurately realized by performing the applicable Bell basis measurement, single-qubit measurement, and local unitary operation instead of a multiparticle joint measurement. The splitting process of quantum information is realized through a convenient operation. Secondly, compared with some previous schemes, the efficiency of the total scheme has been improved in principle, and the qubit consumption is reduced. Finally, the security of the quantum information splitting scheme is analyzed from the perspectives of external attacks and participant attacks. It is proved that our scheme can effectively resist internal participant attacks and external eavesdropper attacks.     

Controlled Remote State Preparation of an Arbitrary Four-Qubit Entangled Cluster-Type State Using Seven-Qubit Cluster State

We propose a deterministic protocol for remotely preparing an arbitrary four-qubit entangled cluster-type state. In our protocol, a seven-qubit cluster state is employed to link the two senders (Alice and Bob) and the receiver Charlie. The to-be-prepared state is realized successfully with the probability of 100 % by performing the local unitary operation and classical communication.     

利用三粒子W态隐形传送任意三粒子W态

提出一个任意三粒子W态从发送者传送给两个接收者任意一个的量子隐形传送方案.该方案用三个三粒子W态作为量子信道,且有两种方法实现传送目的.若发送者进行三次Bell态测量,想得到所需传送三粒子W态的接收者根据发送者的Bell态测量结果和另一个接收者在计算基{|0>,|1>}下的测量结果实施适当的幺正变换操作,就可以一定概率成功地隐形传送三粒子W态;分析表明如果改变操作秩序,成功实现量子隐形传态的概率不会受到影响.同时,该方案可推广至隐形传送N(N≥4)粒子W态,这时需要用N个三粒子W态作为量子信道.发送者做N次Bell态测量,接收者根据如前所述的所有测量结果实施相应的幺正变换,即可完成对N粒子W态的隐形传送.     

Teleportation of an Arbitrary Two-Particle State via a Single Cluster-Class State

Teleportation of an arbitrary two-qubit state with a single partially entangled state, a four-qubit linear cluster-class state, is studied. The case is more practical than previous ones using maximally entangled states as the quantum channel. In order to realize teleportation, we first construct a cluster-basis of 16 orthonormal cluster states. We show that quantum teleportation can be successfully implemented with a certain probability if the receiver can adopt appropriate unitary transformations after receiving the sender＇s cluster-basis measurement information. In addition, an important conclusion can be obtained that a four-qubit maximally entangled state （cluster state） can be extracted from a single copy of the cluster-class state with the same probability as the teleportation in principle.     

Controlled Joint Remote State Preparation of an Arbitrary Equatorial Two-Qubit State

We propose a scheme for controlled joint remote state preparation of an arbitrary equatorial two-qubit state by using a seven-qubit entangled state as the quantum channel. In this scheme, two senders wish to help a receiver to remotely prepare an arbitrary equatorial two-qubit state, and the receiver can obtain the original quantum state with 100% success probability by performing the appropriate unitary operations.

     

Short-Distance Teleportation of an Arbitrary Two-Qubit State Via a Bell State

We propose a scheme for teleportation of an arbitrary two-qubit state by using a Bell state as the quantum channel working together with an auxiliary qubit. Our scheme needs less entanglement resource, but at the cost of shortening teleportation distance. This is because that in order to successfully recover the teleported state, both sender and receiver need to implement quantum-gate operations on the shared auxiliary qubit. So, the auxiliary qubit must be close to both sender and receiver. Otherwise, the sender and receiver cannot carry out quantum-gate operations on it. Thus, our scheme is invalid for long-distance teleportation. But for short-distance teleportation, our scheme is an optimal choice because it requires less entanglement resource. From a practical point of view, our scheme is very promising for application in quantum teleportation on chip.

     

Splitting an Arbitrary Three-Qubit State by Using Seven-Qubit Composite GHZ-Bell State

We present a scheme for quantum information splitting of an arbitrary three-qubit state by using a seven-qubit composite GHZ-Bell state as quantum channel. We illustrate the procedure in the ion-trap systems, but the scheme can also be realized in other systems.     

Teleportation of an Arbitrary Two-qubit State

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三粒子任意态的量子隐形完全传送

提出一个利用六粒子非贝尔对量子通道对一个任意的三粒子量子态进行隐形传送的方案.发送者Alice对需传送的三粒子量子态与属于自己的纠缠对中的三粒子进行三次Bell基测量,并将测量结果通过经典通道告诉接受者,接受者Bob根据这些信息对自己拥有的粒子进行Toffoli变换,就可使这三粒子处于待发送的原始量子态,从而实现概率为1的量子态隐形传送.利用变换算符的思想,很容易得出塌陷态的表达式以及接受者Bob所做的幺正变换的表达式.     

通过绝热过程实现任意一原子态的隐形传态(英文)

我们利用腔场和激光相互作用,提出一个冗余的、对消相干不敏感的方案,来传输任意一个三能级原子的态.由于原子自发跃迁和腔延迟作用会造成信息丢失,通过用部分绝热过程和适当的原子场耦合的设计,信息丢失能够被有效的抑制,此方案传送成功的几率是0.5,保真度是1.     

Quantum State Sharing of an Arbitrary Three-Atom State by Using Five-Atom Cluster State in Cavity QED

We present a scheme for implementing the deterministic quantum state sharing of an arbitrary three-atom state by using a five-atom cluster state and a Bell-state in cavity QED. In the scheme, it does not involve Bell-state measurement and only needs to perform the single-atom measurements. Our scheme is not sensitive to both the cavity decay and the atom radiation, which is of importance in view of decoherence.     

Quantum Teleportation of an Unknown Two-Atom Entangled State Using Four-Atom Cluster State

A simply protocol for quantum teleportation of an unknown two-atom entangled state using four-atom cluster state is investigated in cavity quantum electrodynamics (QED). In this protocol, by using a one-dimensional maximally four-atom cluster state as quantum channel, an unknown two-atom entangled state can be transmitted from the sender (Alice) to the receiver without apparent joint Bell-state measurement. According to the results measured by the sender, the receiver can obtain the original state with unit successful probability. The important features of our scheme can also be demonstrated in ion trap system.     

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.