Joint Remote State Preparation Protocol Research Articles

Joint remote state preparation protocol for non-maximally entangled W-states and fidelity analysis in noisy environments

In this paper, we discuss a protocol for preparing a non-maximally entangled W-state at a distant location where there are two parties intending such creation each of whom possesses only partial information about the state. These two parties along with a third party Controller, participate in a single protocol in order to create the intended state in the hands of a fourth party. The role of the controller is to fabricate an 8-qubit entangled state and distribute the respective qubits involved in the entangled state to the relevant parties and thereby creating a noisy quantum channel. The protocol is first ideally discussed in the noise-free case which is then a perfect joint remote state preparation protocol with fidelity 1. Then, we discuss the performance of the protocol in the presence of noise in which the fidelity is diminished. We consider three different types of noises and analyze the variation of fidelity of the process.

Multi‐hop joint remote state preparation of general hybrid entangled multi‐qudit states via distinct Einstein‐Podolsky‐Rosen channels

AbstractJoint Remote State Preparation provides a useful way to securely transfer the known quantum states to the distant nodes. However, the limitation of resources often leads to the quantum channels constructed by distributed entangled pairs being incompatible with the transmitted states. In order to overcome this problem, a novel Joint Remote State Preparation protocol was proposed for transmitting general multi‐qudit states over quantum networks, providing a promising pathway to utilise the available Einstein‐Podolsky‐Rosen (EPR) channels with different levels. Several scenarios under noisy environments were discussed and some properties of the fidelity when transmitting the multi‐qudit state were demonstrated. It was demonstrated that both the prepared state and the kind of the noises could restrict the number of the participant nodes. Our scheme leverages the existing quantum resources, which addresses the issue of insufficient entanglement resources. This approach is easily adaptable to other quantum network structures, offering a potential solution for constructing a universal quantum network.

Enhancing the fidelity of joint remote state preparation by weak measurement

In this paper, the technique of weak measurement is employed in order to enhance the fidelity of joint remote state preparation (JRSP) protocol under decoherence. We design a quantum circuit of joint remote preparation of a single-qubit state through a GHZ state. Then, we analytically derive the average fidelity of the JRSP protocol under four types of noise usually encountered in real-world implementations of quantum communication protocols, i.e. the phase-flip, depolarizing, amplitude-damping and bit-flip noise. Our study shows that the application of weak measurement and measurement reversal could enhance the average fidelity of the JRSP process under the influence of phase-flip, depolarizing, amplitude-damping noise for most values of the decoherence parameters. If the JRSP process suffers from the bit-flip noise, the weak measurement technique is not useful for increasing the average fidelity.

Effect of noise on joint remote preparation of an arbitrary two-qubit state via a Brown state

We present a scheme to realize joint remote state preparation (JRSP) of an arbitrary two-qubit state via a seven-qubit Brown state which is subjected to the noisy environment. Two basic noise models, the amplitude-damping noise and the phase-damping noise, are considered. The noise only affects the transmitted qubits of the quantum channel in our protocol. We put forward the detailed processes of JRSP protocol with these two kinds of noise. It is found out that the fidelities for both kinds of noise depend on the decoherence noisy rate and the amplitude factor of the prepared state. Interesting, the effect of phase-damping noise is much stronger than that of the amplitude-damping noise. Our study will contribute to the research on the effect of quantum noise for JRSP.

Deterministic joint remote preparation of arbitrary multi-qubit states via three-qubit entangled states

We propose an efficient scheme for joint remote state preparation (JRSP) of arbitrary multi-qubit states from two senders to one receiver with the 100% successful probability. Quantum channel is composed of maximally three-qubit entangled states, and several special mutually orthogonal measurement basis are constructed without the introduction of auxiliary particles. We also calculate the total classical communication cost required in the JRSP processes. The concrete JRSP procedures for remotely preparing single-qubit and two-qubit states are illustrated to prove explicitly the feasibility of this JRSP protocol.

Coping with noise in joint remote preparation of a general two-qubit state by using nonmaximally entangled quantum channel

Noise is unavoidable in practice and its presence makes quantum protocols imperfect. In this paper we consider a way to cope with typical types of noise in joint remote preparation of an arbitrary 2-qubit state. The idea is to use nonmaximally (in stead of maximally) entangled states as the initial quantum channel. Because noise changes the initial quantum channel we can beforehand tailor it to be nonmaximally entangled by introducing free parameters which, depending on given types of noise, can be controlled so that due to the affect of noise the initial quantum channel becomes closest to the maximally entangled one, thus optimizing the performance of the joint remote state preparation protocol. The dependence of the optimal averaged fidelities on the strength of various types of noise is represented by phase diagrams that clearly separate the quantum domain from the classical one.

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.

Optimal joint remote state preparation in the presence of various types of noises

A main obstacle faced by any quantum information processing protocol is the noise that degrades the desired coherence/entanglement. In this work we study by means of Kraus operators the effect of four typical types of noises on the quality of joint remote state preparation of a single-qubit state using a three-qubit Greenberger–Horne–Zeilinger-type state as the initial quantum channel. Assuming that two of the three involved qubits independently suffer a type of noise, we derive analytical expressions not only for the optimal averaged fidelities but also for the boundaries in phase space of the domains in which the joint remote state preparation protocol outperforms the classical one. Detailed discussion is given for each of the total 16 noisy scenarios. We also provide physical interpretation for the obtained results and outline possible future topics.

Effects of noises on joint remote state preparation via a GHZ-class channel

Using a GHZ-class state as quantum channel, we investigate the joint remote preparation of a qubit state in Pauli noise environments. By analytically solving the master equation in Lindblad form, we calculate the time evolution of the GHZ-class channel under different noisy conditions and then obtain the fidelity of the joint remote state preparation (JRSP) process and the corresponding average fidelity. We find that the fidelity depends on the noise type, the GHZ-class state, the initial state to be remotely prepared, and the Pauli decoherence rate. We also find that how two senders share the polar angle information of initial state plays an important role in the fidelity, and information sharing reduces the ability to resist the influence of Pauli noises in our JRSP protocol. Furthermore, how the two senders share the phase information affects the intensity of the bit-phase flip noise and the bit flip noise acting on the average fidelity. Besides, the fidelity of our JRSP protocol achieved via the maximally entangled channel is larger than that achieved via the partially entangled channel.

Improved Deterministic N-To-One Joint Remote Preparation of an Arbitrary Qubit via EPR Pairs

Recently, Bich et al. (Int. J. Theor. Phys. 51: 2272, 2012) proposed two deterministic joint remote state preparation (JRSP) protocols of an arbitrary single-qubit state: one is for two preparers to remotely prepare for a receiver by using two Einstein-Podolsky-Rosen (ERP) pairs; the other is its generalized form in the case of arbitrary N (N > 2) preparers via N ERP pairs. While examining these two protocols, we find that the success probability for the receiver achieving the desired state is not deterministic, i.e., \(P^{N>2}_{suc}<1\), for N > 2 preparers in the second protocol. Through constructing two sets of adaptive projective measurement bases for both the real space and the complex space, an improved deterministic N-to-one JRSP protocol for an arbitrary single-qubit state is presented. Analysis shows our protocol can truly achieve the unit success probability, i.e., \(P^{N\geq 2}_{suc}=1\). What is more, the receiver can be randomly assigned even after the distribution of the qubits of EPR pairs, so it is more flexible and applicable in the network situation.

Deterministic joint remote preparation of an arbitrary two-qubit state in the presence of noise

Using two tripartite Greenberger—Horne—Zeilinger (GHZ) states as the shared channels, we investigate the noise effects on the deterministic joint remote preparation of an arbitrary two-qubit state. By unitary matrix decomposition procedure, we first construct the quantum logic circuit of the deterministic joint remote state preparation protocol. Then, we analytically derive the fidelity and the average fidelity for the deterministic joint remote preparation of an arbitrary two-qubit state and of four types of special two-qubit states under the influence of the Pauli noises. It is found that the fidelity depends on the noise types, the qubit-environment coupling strength, and the state to be remotely prepared. Moreover, even if the two GHZ channels are subject to the same environmental noises, the average fidelities for remotely preparing different two-qubit states display different time evolution behaviors. The remote preparation of the identical two-qubit states also shows that the average fidelities affected by different noisy environments exhibit different evolution actions.