Remote Preparation Research Articles

Teleportation based non-degenerate discordant remote state preparation

Remotely preparing quantum states, which possess some desired features, is an important task for future quantum network host providers. On the other hand, the non-degenerate discordant two-qubit states, the states with different left and right quantum discords, is necessary for the implementation of some quantum information and quantum computation processes. This paper presents a new preparation scheme of such states realized by the asymmetric quantum correlation teleportation (AQCT) protocol i.e. quantum correlation teleportation via two different quantum channels. In this way, some properties of AQCT protocol are studied to achieve the most appropriate and least expensive procedure of preparing the asymmetric discordant two-qubit quantum states.

Effect of noise on deterministic remote preparation of an arbitrary two-qudit state by using a four-qudit χ-type state as the quantum channel

We present a protocol for remote preparation of an arbitrary two-qudit state by using a four-qudit [Formula: see text]-type state as the quantum channel via positive operator-valued measurement. We first propose the protocol for remote preparation of an arbitrary two-qudit state via positive operator-valued measurement in noiseless environment and then discuss the protocol in noisy environments. Four important quantum decoherence noise models, the dephasing noise, the qudit-flip noise, the qudit-phase-flip noise and the depolarizing noise, are considered in our protocol. The output states and the fidelities of remote state preparation in four different types of quantum noises are presented. It is shown the protocol for remote state preparation via positive operator-valued measurement with [Formula: see text]-type state has the advantage of transmitting less particles for remote preparing an arbitrary two-qudit state. The fidelities of remote state preparation depend on the coefficients of original two-qudit state and the decoherence rates of the noise models.

Deterministic bidirectional controlled remote preparation without information splitting

By using a five-qubit entangled state as the quantum channel, we propose an efficient protocol for implementing bidirectional controlled remote preparation of arbitrary single-qubit states with unit success probability. The senders do not need to perform information splitting and additional unitary operations due to the elaborately constructed measurement basis. Furthermore, three-bit classical communication can be saved at the controller’s broadcast channel with the aid of network coding. Then, we consider the effect of five-type noises on the proposed protocol. It is found that the fidelities of the output states are dependent on the coefficients of the prepared state and the noise parameter. Interestingly, the fidelity is irrelevant to the participators’ measurement results except in the amplitude-damping and phase-damping noises.

Hierarchical Controlled Remote Preparation via the Brown State Under the Noisy Environment

Utilizing the Brown state as the quantum channel, we put forward a deterministic scheme to realize hierarchical controlled remote preparation of an arbitrary single-qubit state from the sender to anyone of the recievers. There exists a hierarchy among the receivers as far as the power to reconstruct the prepared state is concerned. The upper-grade receiver needs the cooperation of any two other receivers. While the receiver at the lower grade requires the support of all the remaining receivers. It means the receiver at the upper grade has greater power to recover initial state. Compared with the previous hierarchical controlled remote preparation protocols of an arbitrary single-qubit state, our scheme first uses Brown state as the entangled resource and has higher security as the upper-grade receiver needs the consents of at least two other receivers. In addition, we investigate the proposed scheme under the noisy environment.

제3자 없이 수행할 수 있는 상호 양자개체인증

본 논문은 제3자 없이 통신구성원들이 상호간에 인증할 있는 양자개체인증 프로토콜을 제안한다. 기존 인증 프로토콜들은 안전성과 효율성을 이유로 신뢰할 수 있는 제3자(trusted third party)의 제어를 받아서 상호 개체인증을 수행한다. 하지만, 신뢰할 수 있는 제3자를 구현하는 것은 매우 어려운 일이며, 이러한 제3자가 구현되었다 하더라도 프로토콜 수행 중에 악의적인 노드가 되어 통신구성원들의 인증키를 탈취하는 문제가 발생할 위험이 항상 존재한다. 본 논문에서 제안하는 프로토콜은 remote Bell state preparation 기법을 이용함으로 제3자 없이 통신구성원들 간의 상호인증이 가능하기 때문에 제3자에 의한 내부자 공격으로부터 완전히 안전하다. 또한, 제안하는 프로토콜은 선형광학으로 생성하고 측정할 수 있는 두 Bell 상태(states)｜ΦSUP±/SUP SUBAB/SUB만 사용하기 때문에 실제 하드웨어로 쉽게 구현이 가능하다는 장점을 갖는다.

Joint multi-party remote preparation of arbitrary qudit states via a <italic>d</italic>-level six-qudit Cluster state

We propose two protocols for joint, multi-party remote preparation of qudit states by using a d -level six-qudit Cluster state as the quantum channel. The first protocol is used for the joint remote preparation of an arbitrary two-qudit state via the d -level six-qudit Cluster state. The second is used for bi-directional joint remote preparation of an arbitrary single-qudit state via a d -level six-qudit Cluster state. All senders share information about the prepared state. The first sender applies Positive Operator-Valued Measurement (POVM) on her entangled particles in accordance with her information about the prepared state, while the second sender performs projective measurements in accordance with the information about the prepared state and the first sender’s measurement results. The receiver can prepare the original state by performing a corresponding unitary operation according to the measurement results from all the senders. These two protocols have the advantage of being able to provide a high channel capacity by using a d -level Cluster state as the quantum channel.

Efficient scheme for remote preparation of arbitrary n-qubit equatorial states

Recently, a scheme for deterministic remote preparation of arbitrary multi-qubit equatorial states was proposed by Wei et al. [Quantum Inf. Process. 17 70 (2018)]. It is worth mentioning that the construction of mutual orthogonal measurement basis plays a key role in quantum remote state preparation. In this paper, a simple and feasible remote preparation of arbitrary n-qubit equatorial states scheme is proposed. In our scheme, the success probability will reach unit. Moreover, there are no coefficient constraint and auxiliary qubits in this scheme. It means that the success probabilities are independent of the coefficients of the entangled channel. The advantage of our scheme is that the mutual orthogonal measurement basis is devised. To accomplish the quantum remote state preparation (RSP) schemes, some new sets of mutually orthogonal measurement basis are introduced.

Bidirectional controlled remote state preparation in three-dimensional system

We present a novel scheme for bidirectional controlled remote state preparation (BCRSP) in a three-dimensional system with a six-qutrit entangled state as the quantum channel. In this scheme, two distant parties, Alice and Bob, are not only senders but also receivers. Alice wants to remotely prepare a single-qutrit equatorial state at Bob’s site, while at the same time, Bob wishes to help Alice by remotely preparing another single-qutrit equatorial state. It is shown that, only if the two senders and the controller collaborate with each other, the BCRSP can be completed successfully.

Deterministic remote preparation of arbitrary single-qubit state via one intermediate node in noisy environment

We propose a remote state preparation scheme working in noisy environment via one intermediate node. Firstly, we report the remote preparation of an arbitrary single-qubit state with one intermediate node in ideal environment. Afterwards, we investigate the influence of four kinds of representative noises that are commonly encountered in practical applications of quantum communication protocols. Detailed analysis indicates that the fidelities of the output state rely on the coefficients of the prepared state and the decoherence rate. The turning point is λ=0.5 in both the bit-flip and phase-flip noisy channels. The fidelity in the depolarizing channel is related with the decoherence rate, and independent with the phase parameters.

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 state preparation of four-qubit cluster type with tripartite involvement

Cluster state is deemed to be a significant quantum resource, for it can encode much information; its remote preparation is significant to the quantum information processing. In the paper, a novel joint remote quantum state preparation protocol is proposed, in which three participants are included, and they are cooperatively involved for the protocol accomplishment within the configuration constructed by the four-qubit cluster type and EPR pairs. The cluster-type state is successful prepared via the appropriate unitary operations after the relevant participants perform the projection measurement. The presented protocol shows highly secure and could stand against the external eavesdropper.

Controlled Asymmetric Bidirectional Hybrid of Remote State Preparation and Quantum Teleportation

We propose a protocol of Asymmetric implementing controlled joint remote state preparation and meanwhile realizing controlled quantum teleportation. That is to say, Alice wants to teleport an arbitrary two-qubit state to Bob, and Bob wants to remotely prepare a known state for Alice via the control of supervisors Charlie. Compared with previous studies for the schemes of solely bidirectional quantum teleportation, the new protocol is a kind of hybrid approach of information communication which makes the quantum channel multipurpose.

Controlled Joint Remote Preparation of a Six-Qubit Cluster-Type State by Using GHZ States

A scheme for the controlled joint remote preparation of an arbitrary six-qubit cluster-type state by using only two sets of five-qubit GHZ states as quantum channel is proposed. In our scheme, Alice firstly performs two sets of two-qubit projective measurement according to the real coefficients and the complex coefficients of the desired six-qubit cluster-type state. Then, the controller Charlie must apply another two-qubit projective measurement according to the Alice’s measurement result. Finally, Bob can obtain the desired six-qubit cluster-type state according to an appropriate unitary operation. Our scheme can achieve unit success probability.

Remote Blind State Preparation with Weak Coherent Pulses in the Field.

Quantum computing has seen tremendous progress in past years. Due to implementation complexity and cost, the future path of quantum computation is strongly believed to delegate computational tasks to powerful quantum servers on the cloud. Universal blind quantum computing (UBQC) provides the protocol for the secure delegation of arbitrary quantum computations, and it has received significant attention. However, a great challenge in UBQC is how to transmit a quantum state over a long distance securely and reliably. Here, we solve this challenge by proposing a resource-efficient remote blind qubit preparation (RBQP) protocol, with weak coherent pulses for the client to produce, using a compact and low-cost laser. We experimentally verify a key step of RBQP-quantum nondemolition measurement-in the field test over 100km of fiber. Our experiment uses a quantum teleportation setup in the telecom wavelength and generates 1000secure qubits with an average fidelity of (86.9±1.5)%, which exceeds the quantum no-cloning fidelity of equatorial qubit states. The results prove the feasibility of UBQC over long distances, and thus serves as a key milestone towards secure cloud quantum computing.

Multicast-based multiparty remote state preparation schemes of two-qubit states

We propose two novel schemes for multicast-based remote preparation of two kinds of two-qubit states with the aid of the eight-qubit entangled states as the quantum channels. In our scenario, the different encoded information is transmitted synchronously from one sender to many spatially separated receivers. Moreover, it is shown that the first scheme is realized successfully and efficiently, and only the four-qubit projective measurement and appropriate local unitary operations are needed. In particular, the eight-qubit partially entangled channel is utilized in the second.

Controlled joint remote preparation of an arbitrary N-qubit state

In this paper, a novel scheme for controlled joint remote preparation of an arbitrary N-qubit state is proposed. In the scheme, Alice and David prepare an arbitrary N-qubit state on Bob’s side under the control of Charlie by using a 3N + 1-qubit entangled state as the quantum channel. First, the quantum channel is constructed through the Hadamard and controlled-NOT operations. Then, Alice, David, and Charlie each perform the quantum measurements on their own qubits. To ensure that the original state can be prepared determinately, two algorithms are proposed to construct the measurement bases for Alice and David. Finally, Bob reconstructs the original state with several appropriate unitary operations on his qubits according to the measurement results of Alice, David, and Charlie. To demonstrate the feasibility of the scheme, a remote preparation example of an arbitrary two-qubit state with the scheme is given. At the end of this paper, the efficiency analysis of the scheme and some conclusions is presented. In comparison with previous schemes, the scheme is superior in terms of the capability and efficiency of quantum communication.

Secure quantum remote state preparation of squeezed microwave states

Quantum communication protocols based on nonclassical correlations can be more efficient than known classical methods and offer intrinsic security over direct state transfer. In particular, remote state preparation aims at the creation of a desired and known quantum state at a remote location using classical communication and quantum entanglement. We present an experimental realization of deterministic continuous-variable remote state preparation in the microwave regime over a distance of 35 cm. By employing propagating two-mode squeezed microwave states and feedforward, we achieve the remote preparation of squeezed states with up to 1.6 dB of squeezing below the vacuum level. Finally, security of remote state preparation is investigated by using the concept of the one-time pad and measuring the von Neumann entropies. We find nearly identical values for the entropy of the remotely prepared state and the respective conditional entropy given the classically communicated information and, thus, demonstrate close-to-perfect security.

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.

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.

Deterministic Remote Preparation via the χ State in Noisy Environment

We have proposed two deterministic remote state preparation schemes via the χ state as the entangled channel in ideal environment. In this paper, we re-investigate the schemes in seven types of noises: amplitude-damping, phase-damping, Pauli (bit-flip, phase-flip, bit-phase flip, depolaring) and collective dephasing noise. The fidelity is used to measure how close the output state with the initial state are. It is found that the fidelities are dependent on the amplitude factor, phase factor and noise parameter. Interestingly, the fidelity is irrelated to the participators’ measurement results except in the amplitude-damping and collective dephasing noise. When the prepared states are the specific two- and three-qubit states, the fidelity is periodic in the collective dephasing noise and monotonous in other noises. Moreover, the average fidelity and state-independent average fidelity are calculated to quantify the effect of noise. Among the amplitude-damping, phase-damping and Pauli noises, the Pauli noise has the greatest impact and the phase-damping noise has the smallest impact.