Efficient joint remote preparation of an arbitrary two-qubit state via cluster and cluster-type states

In this paper, we present a possible improvement of the successful probability of joint remote state preparation via cluster states following some ideals from probabilistic joint remote state preparation (Wang et al. in Opt Commun, 284:5835, 2011). The success probability can be improved from $1/4$ to 1 via the same quantum entangled channel by adding some classical information and performing some unitary operations. Moreover, we also discussed the scheme for joint remote preparation via cluster-type states. Compared with other schemes, our schemes have the advantage of having high successful probability for joint preparation of an arbitrary two-qubit state via cluster states and cluster-type states.     

Deterministic remote preparation of arbitrary multi-qubit equatorial states via two-qubit entangled states

We propose an efficient scheme for remotely preparing an arbitrary n-qubit equatorial state via n two-qubit maximally entangled states. Compared to the former scheme (Wei et al. in Quantum Inf Process 16:260, 2017) that has the 50% successful probability when the amplitude factors of prepared states are \(2^{-n{/}2}\), the probability would be increased to 100% by using of our modified proposal. The feasibility of our scheme for remote preparation arbitrary multi-qubit equatorial states is explicitly demonstrated by theoretical studies and concrete examples.     

Optimal remote preparation of arbitrary multi-qubit real-parameter states via two-qubit entangled states

In this paper, we present an efficient scheme for remote state preparation of arbitrary n-qubit states with real coefficients. Quantum channel is composed of n maximally two-qubit entangled states, and several appropriate mutually orthogonal bases including the real parameters of prepared states are delicately constructed without the introduction of auxiliary particles. It is noted that the successful probability is 100% by using our proposal under the condition that the parameters of prepared states are all real. Compared to general states, the probability of our protocol is improved at the cost of the information reduction in the transmitted state.     

Remote preparation of an arbitrary multi-qubit state via two-qubit entangled states

We propose a novel scheme for remote preparation of an arbitrary n-qubit state with the aid of an appropriate local \(2^n\times 2^n\) unitary operation and n maximally entangled two-qubit states. The analytical expression of local unitary operation, which is constructed in the form of iterative process, is presented for the preparation of n-qubit state in detail. We obtain the total successful probabilities of the scheme in the general and special cases, respectively. The feasibility of our scheme in preparing remotely multi-qubit states is explicitly demonstrated by theoretical studies and concrete examples, and our results show that the novel proposal could enlarge the applied range of remote state preparation.     

Controlled remote state preparation protocols via AKLT states

In this paper, we proposed two controlled remote state preparation of an arbitrary single-qubit state schemes one for deterministic controlled remote state preparation the other for probabilistic controlled-joint remote state preparation with 2/3 probability. Both of them used the Affleck–Kennedy–Lieb–Tasaki (AKLT) state which consisted of bulk spin-1’s and two spin-1 \(/\) 2’s at the ends. Up to now, no RSP protocols using AKLT gapped ground states as a shared quantum resource had been presented thus far and Fan et al. showed the other AKLT property was that if we performed a Bell measurement on bulk, then a maximally entangled state would be shared by two ends. We utilized these properties to develop our controlled protocols.     

Deterministic remote two-qubit state preparation in dissipative environments

We propose a new scheme for efficient remote preparation of an arbitrary two-qubit state, introducing two auxiliary qubits and using two Einstein–Podolsky–Rosen (EPR) states as the quantum channel in a non-recursive way. At variance with all existing schemes, our scheme accomplishes deterministic remote state preparation (RSP) with only one sender and the simplest entangled resource (say, EPR pairs). We construct the corresponding quantum logic circuit using a unitary matrix decomposition procedure and analytically obtain the average fidelity of the deterministic RSP process for dissipative environments. Our studies show that, while the average fidelity gradually decreases to a stable value without any revival in the Markovian regime, it decreases to the same stable value with a dampened revival amplitude in the non-Markovian regime. We also find that the average fidelity’s approximate maximal value can be preserved for a long time if the non-Markovian and the detuning conditions are satisfied simultaneously.     

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.     

Controlled remote state preparation of arbitrary two and three qubit states via the Brown state

In this paper, several new protocols for the controlled remote state preparation (CRSP) by using the Brown state as the quantum channel are proposed. Firstly, we propose a CRSP protocol of an arbitrary two qubit state. Then, the CRSP protocol of an arbitrary three qubit state, which has rarely been considered by the previous papers, is investigated. The coefficients of the prepared states can be not only real, but also complex. To design these protocols, some useful and general measurement bases are constructed, which can greatly reduce the restrictions for the coefficients of the prepared states. The security analysis is provided in detail. Moreover, receiver??s all recovery operations are summarized into a concise formula.     

Deterministic remote preparation via the Brown state

We propose two deterministic remote state preparation (DRSP) schemes by using the Brown state as the entangled channel. Firstly, the remote preparation of an arbitrary two-qubit state is considered. It is worth mentioning that the construction of measurement bases plays a key role in our scheme. Then, the remote preparation of an arbitrary three-qubit state is investigated. The proposed schemes can be extended to controlled remote state preparation (CRSP) with unit success probabilities. At variance with the existing CRSP schemes via the Brown state, the derived schemes have no restriction on the coefficients, while the success probabilities can reach 100%. It means the success probabilities are greatly improved. Moreover, we pay attention to the DRSP in noisy environments under two important decoherence models, the amplitude-damping noise and phase-damping noise.     

Effect of noise on deterministic joint remote preparation of an arbitrary two-qubit state

Quantum communication has attracted much attention in recent years. Deterministic joint remote state preparation (DJRSP) is an important branch of quantum secure communication which could securely transmit a quantum state with 100% success probability. In this paper, we study DJRSP of an arbitrary two-qubit state in noisy environment. Taking a GHZ based DJRSP scheme of a two-qubit state as an example, we study how the scheme is influenced by all types of noise usually encountered in real-world implementations of quantum communication protocols, i.e., the bit-flip, phase-flip (phase-damping), depolarizing, and amplitude-damping noise. We demonstrate that there are four different output states in the amplitude-damping noise, while there is the same output state in each of the other three types of noise. The state-independent average fidelity is presented to measure the effect of noise, and it is shown that the depolarizing noise has the worst effect on the DJRSP scheme, while the amplitude-damping noise or the phase-flip has the slightest effect depending on the noise rate. Our results are also suitable for JRSP and RSP.     

Deterministic controlled bidirectional remote state preparation via a six-qubit entangled state

In this paper, we presented a controlled bidirectional remote state preparation scheme which used the six-qubit entangled state as quantum channel. In our scheme, Alice and Bob can prepare simultaneously an arbitrary single-qubit state in each other’s place with the control of the supervisor Charlie. The success probability for our scheme reaches unit. Furthermore, we analyze the expression of quantum channel for controlled bidirectional remote state preparation. Finally, we discuss the security of our scheme, the detailed security analysis shows that the supervisor Charlie’s control can greatly improve the security of our scheme.

     

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.     

Two efficient schemes for probabilistic remote state preparation and the combination of both schemes

We propose two novel schemes for probabilistic remote preparation of an arbitrary quantum state with the aid of the introduction of auxiliary particles and appropriate local unitary operations. The first new proposal could be used to improve the total successful probability of the remote preparation of a general quantum state, and the successful probability is twice as much as the one of the preceding schemes. Meanwhile, one can make use of the second proposal to realize the remote state preparation when the information of the partially entangled state is only available for the sender. This is in contrast to the fact that the receiver must know the non-maximally entangled state in previous typical schemes. Hence, our second proposal could enlarge the applied range of probabilistic remote state preparation. Additionally, we will illustrate how to combine these novel proposals in detail, and our results show that the union has the advantages of both schemes. Of course, our protocols are implemented at the cost of the increased complexity of the practical realizations.     

Multi-party quantum state sharing of an arbitrary two-qubit state with Bell states

We present a new scheme for sharing an arbitrary two-qubit quantum state with n agents. In our scheme, the sender Alice first shares n Einsein-Podolsky-Rosen (EPR) pairs in Bell states with n agents. After setting up the secure quantum channel, Alice first applies (n − 2) Controlled-Not (CNOT) gate operations, and then performs two Bell-state measurements and (n − 2) single-particle measurements (n >2). In addition, all controllers only hold one particle in their hands, respectively, and thus they only need to perform a single-particle measurement on the respective particle with the basis {|0?, |1?}{{{vert}0rangle, {vert}1rangle}}. Compared with other schemes with Bell states, our scheme needs less qubits as the quantum resources and exchanges less classical information, and thus obtains higher total efficiency.     

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.     

Deterministic remote preparation of an arbitrary qubit state using a partially entangled state and finite classical communication

Quantum Information Processing - We propose a deterministic remote state preparation (RSP) scheme for preparing an arbitrary (including pure and mixed) qubit, where a partially entangled state and...     

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.     

The faithful remote preparation of general quantum states

This paper is to establish a theoretical framework for faithful and deterministic remote state preparation, which is related to the classical Hurwitz theorem. And then based on the new theory various schemes with different characteristics are presented. Moreover, the permutation group and the partially quantum resources have also discussed for faithful schemes.     

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.     

Multi-party quantum state sharing via various probabilistic channels

We present a new scheme to share an arbitrary multi-qubit state between n agents via various probabilistic channels under cooperation of m?1 controllers with a certain probability. Compared with existing ones in this literature, our scheme involves various probabilistic channels, which weakens the requirement for quantum channels. The proposed scheme is symmetric which means even though the designed receiver has no capability of adopting appropriate strategies in introducing auxiliary qubits and performing two-qubit gates, it is still possible to faithfully share a multi-qubit state with assistance of other participants. This scheme involves only single-qubit measurements, CNOT gates, and local two-qubit gates with an auxiliary qubit, which makes it more convenient for physical realization.