Probabilistic Teleportation of a Four-Particle Entangled W State

In this paper, two schemes for teleporting an unknown four-particle entangled W state is proposed. In the first scheme, two partial entangled four-particle states are used as quantum channels, while in the second scheme,four non-maximally entangled particle pairs are considered as quantum channels. It is shown that the teleportation can be successfully realized with certain probability, for both schemes, if a receiver adopts some appropriate unitary transformations. It is also shown that the successful probabilities of these two schemes are different.

Classical Communication Cost and Probabilistic Remote Preparation of Four-Particle Entangled W State

我们在场为由把四个部分纠缠的二粒子的状态用作量隧道的四粒子的纠缠的 W 状态的概率的遥远的准备的一个计划。在这个计划，如果艾莉斯(发送者) 执行四粒子的射影的大小，鲍勃(接收装置) 采用一些，拨出单一的操作，遥远的州的准备能成功地与某些概率被认识到。古典通讯费用也是计算的。然而，准备的成功概率能为四种特殊状态被增加到 1。

Generation of a four-particle entangled state via cross-Kerr nonlinearity

We propose a scheme for generating a genuine four-particle polarisation entangled state ｜χ^00） that has many interesting entanglement properties and potential applications in quantum information processing. In our scheme, we use the weak cross-Kerr nonlinear interaction between field-modes and the non-demolition measurement method based on highly efficient homodyne detection, which is feasible under the current experiment conditions.

Scheme for entanglement concentration of unknown W class states via linear optics

This paper proposes a scheme for entanglement concentration of unknown triparticle W class states with a certain probability. This protocol is mainly based on the coincidences of single-photon detectors and requires single-photon detectors and linear optical elements. The scheme is feasible within current technology.

An applicable and resource-economical scheme for the teleportation of W state via spin-path entangled quantum channel

In this paper, we accomplish the teleportation of an unknown three-particle maximally entangled W state by using a spin-path entangled quantum channel which may be realized experimentally based on the advanced theory and technique in Bose-Einstein condensate （BEC） of molecule, micro-fabricated wave guide and simple quantum logic gate. Similarly, we can make an arbitrary n-particle entangled Greenberger Horne-Zeilinger （GHZ） state （n ≥ 4） teleported through this kind of quantum channel. It may have important applications due to its resource-economic and practical features.

Entanglement concentration for an arbitrary hybrid less-entangled state and W state using quantum dots and a microcavity coupled system

We propose a practical entanglement concentration protocol （ECP） for a hybrid entangled state using quantum dots and a microcavity coupled system. A hybrid less-entangled state can he concentrated to a most-entangled state with a certain probability using only one ancillary single photon. Moreover, using this protocol, we can also concentrate an arbitrary three-particle less-entangled W state using two ancillary photons and classical communication. The proposed protocols provide us with a useful method to concentrate less-entangled states, which can he implemented with current technology.

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 linearoptical 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.

Probabilistic Teleportation of a Three-Particle GHZ State via Two Three-Particle Entangled W States

为从一个发送者移植一个未知三粒子的 GHZ 状态到二接收装置中的任何一个一个的电视的一个计划被建议。在这个计划，量隧道由 twonon-maximally 三粒子的纠缠的 W 状态组成。一个未知三粒子的 GHZ 状态能是如果发送者执行二概括 Bell-statemeasurements 和 Hadamard 操作，当也二接收装置之一介绍是组成电视的三个粒子移植了的期末考试之一的一个辅助粒子时，完美地，电视移植了概率的联盟者状态，当目标咬了，然后与辅助粒子动控制不的手术并且在另外的接收装置的简单大小的帮助下介绍适当单一的转变。单一的转变的 Allkinds 详细被给。现在的计划可以直接被概括到电视港口一未知多，经由二个三粒子的纠缠的 W 状态的粒子 GHZ 状态使用了著名计算机生产厂商他量隧道。

Controlled Secure Quantum Communication Using Pure Entangled W Class States

我们在场 non-maximally 使用的一个控制安全的量通讯协议(纯) 纠缠的 W 说第一，然后为真实的量通讯讨论基本要求。我们证明授权二用户罐头交换他们的秘密在安全地并且同时无条件地净化 non-maximally 纠缠的状态量隧道以后在控制器的帮助下发送消息。我们的量通讯协议在现在的技术以内似乎甚至更可行。

Generation of microwave photon perfect W states of three coupled superconducting resonators

We propose an efficient method for the generation of perfect W states on three microwave superconducting resonators,of which the two nearest neighbors are coupled by a symmetric direct current superconducting quantum interference device(dc-SQUID).With suitable external magnetic fluxes applied to the dc-SQUID symmetry loops,on-chip tunable interactions between neighboring resonators can be realized,and different perfect W states can be deterministically created on-demand in one step.Numerical simulations show that high-fidelity target states can be generated and our scheme is robust against imperfect parameter tuning and environment-induced decoherence.The present work may have potential applications for implementing quantum computation and quantum information processing based on microwave photons.

Entanglement dynamics of a three-qubit system with different interatomic distances

We investigate the tripartite entanglement dynamics of three two-level atoms in a multi-mode vacuum field. By considering the influences of the interatomic distance and the initial condition on the lower bound of concurrence and the tripartite negativity, we show that an optimal interatomic distance can be found to minimize the collective damping. Interestingly, at the same optimal distance, the tripartite entanglement would be maximized in the open dynamics process. In the case of shorter interatomic distance, the tripartite entanglement can display the oscillatory behavior in the initial short-time limit and be trapped in a stationary value in the long-time limit. In addition, the tripartite entanglement for the general situation with different interatomic distances is also discussed.

Preparation of entangled simultaneous nonresonant atomic states through atom-field interaction

A scheme is proposed for generating a three-atom maximal entanglement W state. It is based on the simultaneous nonresonant interaction of atoms with a single-mode cavity field. Our scheme is insensitive to the cavity field, so the cavity field in our scheme can be initially in thermal states.

Preparation of Entangled Atomic States Through Resonant Atom-Field Interaction

一个计划被建议因为二原子的格言联盟者的产生纠缠了状态，多原子格言联盟者纠缠了 W 班的状态。计划与一个单个模式的洞基于原子的同时的反响的相互作用删除。它不要求相互作用时间的精确调整。需要完成产生的时间不与原子的数字增加。

Probabilistic Teleportation of an Unknown One-Particle State by a Three-Particle General W State

<正> Two schemes for teleporting an unknown one-particle state are proposed when a general W state is utilizedas quantum channel.In the first scheme,after the sender(Alice)makes a Bell-state measurement on her particles,therecipient(Bob)performs a Von Neumann measurement and introduces an auxiliary particle,and carries out a unitarytransformation on his particle and the auxiliary particle,and performs a Von Neumann measurement on the auxiliaryparticle to confirm whether the teleportation succeeds or not.In the second scheme,the recipient(Bob)does not need toperform the first Von Neumann measurement or introduce the auxiliary particle,which is necessary in the first scheme.It is shown that the maximal probabilities of successful teleportation of the two schemes are identical if the recipient(Bob)performs an appropriate unitary transformation and adopts a proper particle on which he recovers the quantuminformation of state to be teleported.

Deterministic joint remote state preparation of arbitrary single- and two-qubit states

In this paper, two novel schemes for deterministic joint remote state preparation（JRSP） of arbitrary single- and twoqubit states are proposed. A set of ingenious four-particle partially entangled states are constructed to serve as the quantum channels. In our schemes, two senders and one receiver are involved. Participants collaborate with each other and perform projective measurements on their own particles under an elaborate measurement basis. Based on their measurement results,the receiver can reestablish the target state by means of appropriate local unitary operations deterministically. Unit success probability can be achieved independent of the channel＇s entanglement degree.

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 communication cost required in this scheme are also calculated.

Influence of Dissipation on Multiparticle Entanglement Transfer

We investigate the influence of the initial mixture of qubits and the dissipation on the entanglement transferfrom three-qubit Greenberger-Horne-Zeilinger (GHZ) and W state fields to three matter qubits,which are trapped inthree spatially separated cavities.We find that at gt≈11.07,the entanglement transfer can be almost complete nomatter what state the qubits are initially prepared in.When the dissipation is taken into account,we tind that thespontaneous emission plays the similar role to the cavity damping in the entanglement transfer,and the decay rate ofthe GHZ state is larger than that of the W state.

On the correspondence between three nodes W states in quantum network theory and the oriented links in knot theory

The GHZ states and W states are two fundamental types of three qubits quantum entangled states. For finding the knotted pictures of three nodes W states, on the one side, we empty any one node, thus obtaining three degenerated twonode W states, then we find the nonzero submatrix of the corresponding covariance correlation tensor in quantum network theory. On the other side, excepting the linkage 41 corresponding to Bell bases, we conjecture that the another one possible oriented link （which is composed of two-component knots entangled with each other and has four crossings） would be the required knotted pictures of the two nodes W states, thence obtain the nonzero submatrix of the Alexander relation matrix in the theory of knot crystals for these knotted pictures. The equality of the two nonzero submatfices of different kinds thus verify the exactness of our conjecture. The superposition of three knotted pictures of two-node W states from different choices of the emptied node gives the knotted pictures of three-node W states, thus shows the correspondence between three-node W states in quantum network theory and the oriented links in knot theory. Finally we point out that there is an intimate and simple relationship between the knotted pictures of GHZ states and W states.