Teleportation with Tripartite Entangled State via Thermal Cavity

Teleportation schemes with a tripartite entangled state in cavity QED are investigated. The schemes do not need Bell state measurements and the successful probabilities reach optimality. In addition, the schemes are insensitive to both the cavity decay and the thermal field. We first consider two teleportation schemes via a tripartite GHZ state.The first one is a controlled one for an unknown single-qubit state. The second scheme is teleportation of unknown two-atom entangled state. Then we consider teleporting of single-qubit arbitrary state via a tripartite W state.     

Quantum Information Splitting by Using Asymmetric Multi-particle State

We propose schemes for quantum information splitting by using asymmetric multi-particle entangled state. Explicit protocols for the quantum information splitting of a single-qubit state and a two-qubit entangled state via asymmetric three-particle entangled state are illustrated. The four-particle asymmetric entangled state are also used as quantum channel to split the unknown two-qubit entangled state. We also consider the security against certain eavesdropping attacks.     

Scheme for Implementing Assisted Cloning of an Unknown Tripartite Entangled State

In this paper, we propose a protocol which can realize quantum cloning of an unknown tripartite entangled state and its orthogonal complement state with assistance from a state preparer. The first stage of the protocol requires usual teleportation via three entangled particle pairs as quantum channel. In the second stage of the protocol, the perfect copies and complement copies of an unknown state can be produced with the assistance (through a tripartite projective measurement) of the state preparer. We also present a scheme for the teleportation by using non-maximally entangled quantum channel. It is shown that the clones and complement clones of the unknown state can be obtained with certain probability in the latter scheme.     

Teleportation of Unknown Atomic Entangled States Using GHZ Class States

We propose two physical schemes, which can teleport unknown atomic entangled states from user A （Alice） to user B （Bob） via GHZ class states as quantum channel The two schemes are both based on cavity QED techniques. In the two schemes, teleportation and distillation procedures can be realized simultaneously. The second teleportation scheme is more advantageous than the first one.     

Tripartite Controlled Teleportation via a Seven-Qubit Entangled State

We demonstrate that a seven-qubit entangled state can be used to realize the deterministic tripartite controlled teleportation by performing Bell-state measurements, where Alice wants to teleport an arbitrary single-qubit state of qubit a to Bob, Charlie wants to teleport an arbitrary single-qubit state of qubit b to David and at the same time Edison wants to teleport an arbitrary single-qubit state of qubit c to Ford via the control of the supervisor Tom.     

Controlled teleportation of high-dimension quantum-states with generalized Bell-state measurement

In this paper a scheme for controlled teleportation of arbitrary high-dimensional unknown quantum states is proposed by using the generalized Bell-basis measurement and the generalized Hadamard transformation. As two special cases, two schemes of controlled teleportation of an unknown single-qutrit state and an unknown two-qutrit state are investigated in detail. In the first scheme, a maximally entangled three-qutrit state is used as the quantum channel, while in the second scheme, an entangled two-qutrit state and an entangled three-qutrit state are employed as the quantum channels. In these schemes, an unknown qutrit state can be teleported to either one of two receivers, but only one of them can reconstruct the qutrit state with the help of the other. Based on the case of qutrits, a scheme of controlled teleportation of an unknown qudit state is presented.     

Controlled Bidirectional Hybrid of Remote State Preparation and Quantum Teleportation via Seven-Qubit Entangled State

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

Feasible Teleportation Schemes with Five-Atom Entangled State

Teleportation schemes with a five-atom entangled state are investigated. In the teleportation scheme Bell state measurements (BSMs) are difficult for physical realization, so we investigate another strategy using separate measurements instead of BSM based on cavity quantum electrodynamics techniques. The scheme of two-atom entangled state teleportation is a controlled and probabilistic one. For the teleportation of the three-atom entangled state, the scheme is a probabilistic one. The fidelity and the probability of the successful teleportation are also obtained.     

Application of Bipartite and Tripartite Entangled State Representations in Quantum Teleportation of Continuous Variables

We mostly investigate two schemes. One is to teleport a multi-mode W-type entangled coherent state using a peculiar bipartite entangled state as the quantum channel different from other proposals. Based on our formalism,teleporting multi-mode coherent state or squeezed state is also possible. Another is that the tripartite entangled state is used as the quantum channel of controlled teleportation of an arbitrary and unknown continuous variable in the case of three participators.     

Application of Bipartite and Tripartite Entangled State Representations in Quantum Teleportation of Continuous Variables

We mostly investigate two schemes. One is to teleport a multi-mode W-type entangled coherent state using a peculiar bipartite entangled state as the quantum channel different from other proposals. Based on our formalism,teleporting multi-mode coherent state or squeezed state is also possible. Another is that the tripartite entangled state is used as the quantum channel of controlled teleportation of an arbitrary and unknown continuous variable in the case of three participators.     

Probabilistic Teleportation of Three-Qubit Entangled State via Five-qubit Cluster State

A scheme for probabilistic teleportation of an unknown three-qubit entangled state via a five-qubit non-maximally entangled cluster state as quantum channel is proposed. In this scheme, the sender performs two Bell state and a single-qubit measurements on the qubits, the receiver can reconstruct the original state with a certain probability by making appropriate unitary transformations and controlled-not (C-not) operations. 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.     

Probabilistic teleportation of an unknown N-atom state using a two-atom nonmaximally entangled state in cavity QED

We present a scheme for realizing probabilistic teleportation of an unknown N-atom state via cavity QED. This scheme requires only a nonmaximally entangled pair to be used as a quantum channel, so the requirement of entanglement is reduced. In addition, our scheme does not involve the Bell-state measurement and is insensitive to the cavity decay, which is important from the experimental point of view. If the quantum channel is a two-atom maximally entangled state, teleportation of an unknown N-atom state can be realized by a simpler scheme via cavity QED.     

Teleportation of Bipartite Entangled State Without Joint Measurement

In this paper, we present a probabilistic teleportation scheme for unknown bipartite entangled state. By using linear optical elements, we convert the Bell-state measurement into separated single-qubit measurements.     

Deterministic Assisted Clone of an Arbitrary Two- and Three-qubit States via Multi-qubit Brown State

We present two schemes for deterministic assisted clone(DAC) of an unknown two- and three-qubit entangled states with assistance via muti-qubit Brown state. In the schemes, the sender wish to teleport an unknown original entangled state which from the state preparer, and then create a perfect copy of the unknown state at her place. The DAC schemes include two stages. The first stage requires teleportation with Bell-state measurements via a five-qubit Brown state(or seven-qubit Brown state) as the quantum channel. In the second stage, to help the sender realize the quantum cloning, the state preparer performs projective measurements on their own particles which from the sender, then the sender can acquire a perfect copy of the unknown state by means of some appropriate unitary operations. Furthermore, the total success probability for assisted cloning a perfect copy of the unknown state can reach 1 in our schemes.     

Teleportation of an unknown bipartite state via non-maximally entangled two-particle state

In this paper a new scheme for teleporting an unknown entangled state of two particles is proposed. To weaken the requirement for the quantum channel, without loss of generality, two communicators only share a non-maximally entangled two-particle state. Teleportation can be probabilistically realized if sender performs Bell-state measurements and Hadamard transformation and receiver introduces two auxiliary particles, operates C-not operation, single-qubit measurements and appropriate unitary transformations. The probability of successful teleportation is determined by the smaller one among the coefficients' absolute values of the quantum channel.     

Scheme for realizing assisted cloning of an unknown two-atom entangled state via cavity QED

This paper proposes a scheme where one can realize quantum cloning of an unknown two-atom entangled state with assistance of a state preparer in cavity QED. The first stage of the scheme requires usual teleportation. In the second stage of the scheme, with the assistance of the preparer, the perfect copies of an unknown atomic entangled state can be produced.     

Teleportation of Entangled States through Divorce of Entangled Pair Mediated by a Weak Coherent Field in a High-Q Cavity

We propose a scheme to partially teleport an unknown entangled atomic state. A high-Q cavity, supporting one mode of a weak coherent state, is needed to accomplish this process. By partial teleportation we mean that teleportation will occur by changing one of the partners of the entangled state to be teleported. The entangled state to be teleported is composed by one pair of particles, we called this surprising characteristic of maintaining the entanglement, even when one of the particle of the entangled pair being teleported is changed, of divorce of entangled states.     

Controlled Teleportation Using Four-Particle Cluster State

A controlled teleportation scheme is presented. In this scheme, quantum information of a single-qubit state or an entangled two-qubits state is transmitted from a sender (Alice) to a receiver (Charlie) via a four-particle cluster state under the control of the supervisor (Bob). The feature of this scheme is that the teleportation between the sender and the receiver depends on the control of the supervisor.     

Multi-state Quantum Teleportation via One Entanglement State

A multi-sender-controlled quantum teleportation scheme is proposed to teleport several secret quantum states from different senders to a distance receiver based on only one Einstein-Podolsky-Rosen (EPR) pair with controlled-NOT (CNOT) gates. In the present scheme, several secret single-qubit quantum states are encoded into a multi-qubit entangled quantum state. Two communication modes, i.e., the detecting mode and the message mode, are employed so that the eavesdropping can be detected easily and the teleported message may be recovered efficiently. It has an advantage over teleporting several different quantum states for one scheme run with more efficiency than the previous quantum teleportation schemes.     

Scheme for concentration of the unknown GHZ entangled states

We propose two schemes for concentrating unknown nonmaximally tripartite GHZ entangled states via cavity quantum electrodynamics (QED) techniques. The finial pure states obtained from the two schemes are shared by two or three parties. Our schemes only require large-detuned interaction between two driven atoms and the quantized cavity mode, which is insensitive to both the cavity decay and thermal field, thus the schemes are well within current experimental technology.