Joint remote preparation of four-qubit cluster-type states with multiparty

For N+1-sender independently share the classical knowledge of a quantum state, a new scheme for joint remote preparation of four-particle cluster-type states using only two partially two-particle entangled states as quantum channel is presented. In our scheme, each of the senders is just required to perform a bipartite projective measurement, and the receiver adopts some appropriate unitary operation to obtain the original state with certain probability. We also discuss four type information-splitting methods which can make the receiver obtain the unknown state. The classical communication cost is also calculated.     

Experimental architecture of joint remote state preparation

Motivated by some previous joint remote preparation schemes, we first propose some quantum circuits and photon circuits that two senders jointly prepare an arbitrary one-qubit state to a remote receiver via GHZ state. Then, by constructing KAK decomposition of some transformation in SO(4), one quantum circuit is constructed for jointly preparing an arbitrary two-qubit state to the remote receiver. Furthermore, some deterministic schemes of jointly preparing one-qubit and two-qubit states are presented. Besides, the proposed schemes are extended to multi-sender and the partially entangled quantum resources.     

Hierarchical joint remote state preparation in noisy environment

A novel scheme for quantum communication having substantial applications in practical life is designed and analyzed. Specifically, we have proposed a hierarchical counterpart of the joint remote state preparation (JRSP) protocol, where two senders can jointly and remotely prepare a quantum state. One sender has the information regarding amplitude, while the other one has the phase information of a quantum state to be jointly prepared at the receiver’s port. However, there exists a hierarchy among the receivers, as far as powers to reconstruct the quantum state are concerned. A 5-qubit cluster state has been used here to perform the task. Further, it is established that the proposed scheme for hierarchical JRSP (HJRSP) is of enormous practical importance in critical situations involving defense and other sectors, where it is essential to ensure that an important decision/order that can severely affect a society or an organization is not taken by a single person, and once the order is issued, all the receivers do not possess an equal right to implement it. Further, the effect of different noise models (e.g., amplitude damping (AD), phase damping (PD), collective noise and Pauli noise models) on the HJRSP protocol proposed here is investigated. It is found that in AD and PD noise models a higher-power agent can reconstruct the quantum state to be remotely prepared with higher fidelity than that done by the lower-power agent(s). In contrast, the opposite may happen in the presence of collective noise models. We have also proposed a scheme for probabilistic HJRSP using a non-maximally entangled 5-qubit cluster state.     

基于EPR对的任意四粒子Cluster类态全概率联合远程制备

采用4个EPR(Einstein-Podolsky-Rosen)对作为量子信道,提出一种新的全概率联合远程制备任意四粒子Cluster类态方案。在这个新的方案中,一个制备者执行四粒子投影测量,另一个制备者对手中的粒子执行二粒子投影测量。然后,接收者对手中二粒子进行某种幺正操作,并分别对两个辅助粒子进行受控非门操作,从而最终得到需要制备的Cluster类态。与其他制备任意四粒子Cluster类态的全概率制备方案相比,所提协议效率较高,而且在实验上更经济可行。     

Practical single-photon-assisted remote state preparation with non-maximally entanglement

Remote state preparation (RSP) and joint remote state preparation (JRSP) protocols for single-photon states are investigated via linear optical elements with partially entangled states. In our scheme, by choosing two-mode instances from a polarizing beam splitter, only the sender in the communication protocol needs to prepare an ancillary single-photon and operate the entanglement preparation process in order to retrieve an arbitrary single-photon state from a photon pair in partially entangled state. In the case of JRSP, i.e., a canonical model of RSP with multi-party, we consider that the information of the desired state is split into many subsets and in prior maintained by spatially separate parties. Specifically, with the assistance of a single-photon state and a three-photon entangled state, it turns out that an arbitrary single-photon state can be jointly and remotely prepared with certain probability, which is characterized by the coefficients of both the employed entangled state and the target state. Remarkably, our protocol is readily to extend to the case for RSP and JRSP of mixed states with the all optical means. Therefore, our protocol is promising for communicating among optics-based multi-node quantum networks.     

Perfect joint remote state preparation of arbitrary six-qubit cluster-type states

In this paper, a joint remote state preparation protocol, which is applicable to six-qubit cluster states, is presented. The scheme is performed with the help of three quantum channels constituted by eight qubits. A new index of efficiency for JRSP protocols is defined. A comparison is made with the existing similar schemes from which it is concluded that the present scheme utilizes its resources more efficiently. The work is a part of the line of research on transfer and remote preparation of entanglement.     

Joint remote control of an arbitrary single-qubit state by using a multiparticle entangled state as the quantum channel

We present a scheme for joint remote implementation of an arbitrary single-qubit operation following some ideas in one-way quantum computation. All the senders share the information of implemented quantum operation and perform corresponding single-qubit measurements according to their information of implemented operation. An arbitrary single-qubit operation can be implemented upon the remote receiver’s quantum system if the receiver cooperates with all the senders. Moreover, we study the protocol of multiparty joint remote implementation of an arbitrary single-qubit operation with many senders by using a multiparticle entangled state as the quantum channel.     

Multiparty-controlled joint remote state preparation

In this work, we present a novel and efficient information-processing way, multiparty-controlled joint remote state preparation (MCJRSP), to transmit quantum information from many senders to one distant receiver via the control of many agents in a network. We firstly put forward a scheme regarding MCJRSP for an arbitrary single-particle state via Greenberg–Horne–Zeilinger entangled states, and then extend to generalize an arbitrary two-particle state scenario. Notably, different from conventional joint remote state preparation, the desired states cannot be recovered but all of agents collaborate together. Besides, both successful probability and classical information cost are worked out, the relations between success probability and the employed entanglement are revealed, the case of many-particle states is generalized briefly, and the experimental feasibility of our schemes is analysed via an all-optical framework at last. And we argue that our proposal might be of importance to long-distance communication in prospective quantum networks.     

Joint remote state preparation between multi-sender and multi-receiver

In this work, novel schemes for joint remote state preparation are presented, which involve N senders and 2 receivers as well as N senders and 3 receivers. The receivers can simultaneously reconstruct different qubit states containing the joint information from all senders. Compared with the protocols proposed by Su et al. (Int J Quantum Inf 10:1250006 (2012), the information of the prepared states in our schemes is distributed in a different way. Our protocols can be applied not only to states with real parameters but also ones with complex parameters. Moreover, the N-to-2 protocol is suitable for general qubit states besides equatorial states, and the receivers need not to perform any measurements and CNOT gates to reconstruct the states.     

Joint remote state preparation of arbitrary two-particle states via GHZ-type states

The protocols for joint remote preparation of an arbitrary two-particle pure state from a spatially separated multi-sender to one receiver are presented in this paper. We first consider the situation of two sender and demonstrate a flexible deterministic joint remote state preparation compared with previous probabilistic schemes. And then generalize the protocol to multi-sender and show that by only adding some classical communication the success probability of preparation can be increased to four times. Finally, using a proper positive operator-valued measure instead of usual projective measurement, we present a new scheme via two non-maximally entangled states. It is shown that our schemes are generalizations of the usual standard joint remote state preparation scheme and more suitable for real experiments with requirements of only Pauli operations.     

两个基于四粒子纠缠态的量子秘密共享方案

本文分别基于四粒子Cluster态和一个非对称的四粒子纠缠态,提出两个量子秘密共享的方案,其中共享的秘密是未知的单粒子态。秘密的发送者需要对手中的粒子进行Bell基测量,协助者需要对手中的粒子进行测量或者实施幺正操作,最后接收者通过对手中的粒子进行相应的幺正变换或者受控非门操作,就可以重构原始秘密。通过分析表明,任何一个代理者在其他两方协助下是可以恢复秘密的,所以我所提出的方案是高效且安全可靠的。     

Schemes for remotely preparing an arbitrary four-qubit \chi -state

Two schemes via different entangled resources as the quantum channel are proposed to realize remote preparation of an arbitrary four-particle \(\chi \) -state with high success probabilities. To design these protocols, some useful and general measurement bases are constructed, which have no restrictions on the coefficients of the prepared states. It is shown that through a four-particle projective measurement and two-step three-particle projective measurement under the novel sets of mutually orthogonal basis vectors, the original state can be prepared with the probability 50 and 100 %, respectively. And for the first scheme, the special cases of the prepared state that the success probability reaches up to 100 % are discussed by the permutation group. Furthermore, the present schemes are extended to the non-maximally entangled quantum channel, and the classical communication costs are calculated.     

A highly efficient scheme for joint remote preparation of multi-qubit W state with minimum quantum resource

We present a highly efficient scheme for perfect joint remote preparation of an arbitrary \( 2^{n} \)-qubit W state with minimum quantum resource. Both the senders Alice and Bob intend to jointly prepare one \( 2^{n} \)-qubit W state for the remote receiver Charlie. In the beginning, they help the remote receiver Charlie to construct one n-qubit intermediate state which is closely related to the target \( 2^{n} \)-qubit W state. Afterward, Charlie introduces auxiliary qubits and applies appropriate operations to obtain the target \( 2^{n} \)-qubit W state. Compared with previous schemes, our scheme requires minimum quantum resource and least amount of classical communication. Moreover, our scheme has a significant potential for being adapted to remote state preparation of other special states.     

多体非对称纠缠信道的量子受控密集编码

利用多粒子非对称量子纠缠态,提出一种多体高维非对称量子信道的量子受控密集编码方案。采用量子测量的方法控制纠缠量子信道和密集编码经典信息的传送,通过构造幺正变换矩阵和正交量子测量,纯化量子信道,以一定的概率实现量子受控密集编码,解决了实际量子信道退相干影响下最大纠缠态提取的问题,实现了N方发送方和1方接收方之间密集编码传送信息量的控制,提高了密集编码可调控传送信息量,扩大了调控范围。     

Controlled teleportation

In this article, we review the recent development of controlled teleportation which can be used for sharing quantum information and has important applications in remote quantum computation. We introduce the principles of a couple of controlled teleportation schemes with maximally entangled quantum channels and those with pure entangled quantum channels (non-maximally entangled states). The schemes based on maximally entangled states have the advantage of having maximal efficiency although there are differences in their implementations in experiment. In the controlled teleportation schemes using non-maximally entangled states as the quantum channels, the receiver can reconstruct the originally unknown state by adding an auxiliary particle and performing a unitary evolution. No matter what the unknown state is (a single qubit state or an m-qudit state), the auxiliary particle required is only a two-level quantum system.     

Controlled teleportation

In this article, we review the recent development of controlled teleportation which can be used for sharing quantum information and has important applications in remote quantum computation. We introduce the principles of a couple of controlled teleportation schemes with maximally entangled quantum channels and those with pure entangled quantum channels (non-maximally entangled states). The schemes based on maximally entangled states have the advantage of having maximal efficiency although there are differences in their implementations in experiment. In the controlled teleportation schemes using non-maximally entangled states as the quantum channels, the receiver can reconstruct the originally unknown state by adding an auxiliary particle and performing a unitary evolution. No matter what the unknown state is (a single qubit state or an m-qudit state), the auxiliary particle required is only a two-level quantum system.     

Probabilistic quantum relay communication in the noisy channel with analogous space-time code

Motivated by the space-time diversity transmission technique in wireless communications, a novel probabilistic quantum relay communication scheme in the quantum noisy channel is proposed in order to maximize the correct information transmission and the range of quantum communication, in which quantum signal sequences that carrying two-particle entangled states are transmitted from two senders to two relays and then retransmitted to the receiver after space-time encoded by relays. The quantum signal states can be restored via filtering out the channel noise with two-dimensional Bell measurements by the receiver. Analysis and discussions indicate that our scheme can increase and approximately double the range of quantum communication while not to reduce too much quantum signal-to-noise ratio, and meanwhile the security can be guaranteed under strongest collective attacks and LOCC attacks.     

Scheme for assisted cloning an unknown arbitrary three-qubit state

We present a scheme for perfect cloning or orthogonal complementing an unknown arbitrary three-qubit state with assistance. This cloning scheme is divided into two stages. In the first stage, the initial state can be teleported from a sender to a receiver probabilistically via three partially entangled states. In the second stage, the exact copying and orthogonal complementing of the three-qubit state can be created with unity fidelity in a probabilistic manner with the state preparer performing an appropriate tri-particle projective measurement. It is shown that for some special ensembles of the three-qubit state our assisted cloning scheme can be achieved exactly and deterministically.     

Subliminal channels in the identity-based threshold ring signature

Subliminal signature schemes enable senders to hide subliminal messages in a digital signature such that no one besides the authorised subliminal message receiver (called designated receiver) can extract subliminal messages from that signature. This paper is the first to construct subliminal channels on the identity-based threshold ring signature scheme. Two types of subliminal channels are proposed. The first is the unknown-sender subliminal channel, wherein the sender is anonymously sending the subliminal message through an identity-based threshold ring signature. Although the designated receiver can extract the subliminal message and confirm that it is from the known ring of signers, he/she cannot identify the real sender. The other proposed subliminal channel is the known-sender subliminal channel in which the designated receiver can identify the actual sender. Furthermore, the proposed unknown-sender subliminal channel can be extended to permit the sender to send multiple subliminal messages to multiple designated receivers via a single threshold ring signature.     

量子态的概率隐形传态

利用多方控制代理的网络,提出了一个量子隐形传态多量子位的协议。协议中所使用的量子信道有别于已有协议中所使用的量子最大纠缠态。得到的研究结果是,只有在发送方和多方代理合作时,接受方才能得到概率隐形传态的量子信息。因为使用的量子信道是非最大纠缠态,所以该协议更具有实际意义。