基于纠缠交换和团簇态实现二粒子任意态的可控隐形传态

A scheme for controlled teleportation of an arbitrary two-particle state using a maximally entangled EPR pair and a cluster state as the quantum channel is proposed. After receiving Alice's Bell state measurement results, the controller performs a joint measurement on his particles under a non-maximally entangled Bell-basis. The receiver needs to introduce an auxiliary qubit, and performs a series of appropriate unitary transformations on his particles. The original state can be teleported successfully with the probability 2 cos2 θ.

A scheme of teleportation of an arbitrary two-particle state is presented when two pairs of entangled particles are used as quantum channels. After the Bell state measurements are operated by the sender, the original state with deterministic probability can be reconstructed by the receiver when a corresponding unitary transformation is followed.

A scheme for probabilistic teleportation of an unknown three-atom entangled state via a five-atom non-maximally entangled cluster state as quantum channel is proposed. In this scheme, the sender performs two Bell state and a single-atom measurements on the atoms, the receiver can reconstruct the original state with a certain probability by introducing an auxiliary atom and operating appropriate unitary transformations and controlled-not (C-not) operations according to the sender Alice's measurement results. As a result, the probability of successful teleportation is determined by the smallest two of the coefficients' absolute values of the cluster state. The considerable advantage of our scheme is that we employ a non-maximally entangled cluster state as quantum channel in the scheme, which can greatly reduce the amount of entanglement resources and need less classical bits. If we employ a maximally entangled cluster state as quantum channel, the probabilistic teleportation scheme becomes usual teleportation, the successful probability being 100%.

A new representation of an arbitrary and unknown N-particle state is presented at first. As an application, a scheme for teleporting an arbitrary and unknown N-particle state is proposed when N pairs of two-particle non-maximally entangled states are utilized as quantum channels. After Alice (sender) makes Bell-state measurement on her particles, Bob (recipient) introduces an auxiliary particle and carries out appropriate unitary transformation on his particle and the auxiliary particle depending on classical information from Alice. Then, von Neumann measurement that confirms whether the teleportation succeeds or not is performed by Bob on the auxiliary particle. In order to complete the teleportation, another N-1 times operations need to be performed which are similar to the above ones. It can be successfully realized with a certain probability which is determined by the product of the smaller coefficients of non-maximally entangled pairs. All possible unitary transformations are given in detail.

Cluster states, whose model are a remarkably rich structure in measurement-based quantum computation, hold high degree of entanglement, while entanglement is very fragile during the process of transmission because of the inevitable interaction with the environment. We propose two entanglement concentration protocols for four-particle linear cluster states which and are susceptible to the decoherence and the imperfect communication setups. In the first protocol, POVM operators are introduced to maximize the success probability, and the second protocol is based on cross-Kerr nonlinearity which is utilized to check the parity between the original particle and the ancillary particle. Both of the protocols have their own advantages. The first one can be easily realized in experiment by linear optics, while the one with cross-Kerr nonlinearity reach more than 90% success probability by iteration. Since the wide application of cluster states, the two protocols are efficient and valuable to different fields of quantum communication.

We present two schemes for teleporting a three-particle W state by using four-particle state. We consider that the quantum channel is a maximally entangled state (four-particle cluster state) or a non-maximally entangled state. In our schemes, it is necessary to introduce additional particle and construct unitary transformation for realize perfect or probabilistic teleportation of the three-particle W state. In order to transmit target state successfully, Alice firstly performs two controlled-NOT on the initial state. The success probabilities of our two schemes are 1 and 4α 2, respectively. Compared with other schemes proposed before, our scheme has higher efficiency.

We provide two schemes for tripartite Controlled Teleportation (CT) of an arbitrary two-qubit state by using five- and six-qubit cluster states as the quantum channel. It is found that the five-partite cluster state can be used for CT of an arbitrary two-qubit state with three agents and the six-partite cluster state can be used for symmetric CT scheme. In comparison with the similar scheme using the same quantum channels by Muralidharan and Panigrahi [Phys. Rev. A 78 (2008) 062333] and by Menona et al. [arXiv:/0906.3874v1], not multipartite entanglement measurements, which makes our schemes simpler than the existing schemes.

Perfect teleportation of arbitrary n-qudit states using different quantum channels

Necessary and sufficient conditions on n-qudit state for perfect teleportation of an arbitrary single qudit state

The purpose of this paper is to explore how to teleport a low-dimensional (two-dimensional) arbitrary unknown two-qubit cat-like state through a high-dimensional entangled state constituting the quantum channel. We first present a scheme employing a maximally entangled three-qutrit state as the channel. Within this scheme, the sender performs a single-qubit projective measurement and a non-symmetric basis measurement on their particles. Based on these measurement outcomes, the receiver applies specific unitary operations to reconstruct the original cat-like state. Subsequently, the maximally entangled channel is replaced with a non-maximally entangled three-qutrit state. For this probabilistic teleportation scheme, the target state is reconstructed by introducing an auxiliary qubit and performing appropriate operations; the corresponding success probability is derived. Analysis indicates that the non-maximally entangled scheme generalizes the previous maximally entangled approach. Furthermore, both schemes are shown to be directly extendable to quantum channels formed by arbitrary high-dimensional entangled states.

We present two schemes for asymmetric multiparty-controlled teleportation of an arbitrary n-qudit state using different quantum channels between the sender Alice and the controllers, where the first scheme utilizes the generalized Bell states in d-dimensional Hilbert space as the quantum channels and the second scheme takes the generalized multi-particle GHZ maximally entangled states as quantum resources. In addition, Alice shares n generalized Bell states with the receiver Bob in two schemes. In order to avoid performing three-particle or multi-particle joint measurements and consuming more qudits of the multi-particle maximally entangled states, Alice introduces the generalized CNOT gate operations and then obtains higher communication efficiency than the previous schemes based on entanglement swapping.KeywordsQuantum informationQuantum teleportationQuantum state sharing

We demonstrate that two independent spin-1/2 Ising-Heisenberg trimer chains provide an effective platform for the quantum teleportation of any entangled two-qubit state through the quantum communication channel formed by two Heisenberg dimers. The reliability of this quantum channel is assessed by comparing the concurrences, which quantify a strength of the bipartite entanglement of the initial input state and the readout output state. Additionally, we rigorously calculate quantities fidelity and average fidelity to evaluate the quality of the teleportation protocol depending on temperature and magnetic field. It is evidenced that the efficiency of quantum teleportation of arbitrary entangled two-qubit state through this quantum communication channel can be significantly enhanced by moderate magnetic fields. This enhancement can be attributed to the magnetic-fielddriven transition from a quantum antiferromagnetic phase to a quantum ferrimagnetic phase, which supports realization of a fully entangled quantum channel suitable for efficient quantum teleportation. The polymeric trimer chains Cu3(P2O6OH)2 are proposed as an experimental resource of this quantum communication channel, which provides an efficient platform for realization of the quantum teleportation up to moderate temperatures 40 K and extremely high magnetic fields 80 T.

In this paper, the schemes of quantum key distribution and remote state preparation of an arbitrary two-qubit state via four-particle cluster state are proposed. The efficiency of the former is 1 and the probability of the latter is 1(1/4) if the coefficients are real (complex).

A simple scheme for controlled teleportation of an arbitrary two-ion entangled state using a bell and GHZ entangled state as quantum channel is proposed in trapped ion systems. An arbitrary two-ion entangled state can be teleported perfectly with the help of the cooperation. In our scheme the ions are simultaneously excited by a laser. Our scheme is insensitive to both the initial vibrational state and heating. The probability of the success in our scheme is 1.0.

We propose a new protocol for quantum teleportation (QT) which adopts the Brown state as the quantum channel. This work focuses on the teleportation of a single unknown two-qubit state via a Brown state channel in an ideal environment. To validate the effectiveness of our proposed scheme, we conduct experiments by using the quantum circuit simulator Quirk. Furthermore, we investigate the effects of four noisy channels, namely, the phase damping noise, the bit-flip noise, the amplitude damping noise, and the phase-flip noise. Notably, we employ Monte Carlo simulation to elucidate the fidelity density under various noise parameters. Our analysis demonstrates that the fidelity of the protocol in a noisy environment is influenced significantly by the amplitude of the initial state and the noise factor.