Scheme for Implementing Quantum Dense Coding and Teleportation with Tripartite Entangled State in Cavity QED

In this paper, we present a peculiar tripartite entangled state that is inequivalent to both the GHZ state and the W state, and then propose to implement efficient quantum information processing such as quantum dense coding and teleportation with this entangled state in cavity QED. In this scheme the atoms interact with a highly detuned cavity field with the assistance of a strong classical driven field. It does not require the transfer of quantum information between the atomic system and the cavity, and then our scheme is insensitive to both the cavity decay and the thermal field.     

Scheme for Implementing Quantum Dense Coding and Teleportation with Tripartite Entangled State in Cavity QED

In this paper, we present a peculiar tripartite entangled state that is inequivalent to both the GHZ state and the W state, and then propose to implement efficient quantum information processing such as quantum dense coding and teleportation with this entangled state in cavity QED. In this scheme the atoms interact with a highly detuned cavity field with the assistance of a strong classical driven field. It does not require the transfer of quantum information between the atomic system and the cavity, and then our scheme is insensitive to both the cavity decay and the thermal field.     

Scheme for Implementing Perfect Quantum Teleportation with Non-maximally Entangled W-Class State in Cavity QED

We propose an experimentally feasible teleportation scheme with three-atom W-class state, which was first proposed by Agrawal and Pati [P. Agrawal and A. Pati, Phys. Rev. A 74 （2006） 062320 ], in cavity QED. In this scheme atoms interact simultaneously with a nonresonant cavity and there is no energy exchange between the atoms and the cavity. Thus it is insensitive to the cavity decay, which is of importance in view of experiment.     

Scheme for Implementing Perfect Quantum Teleportation with Non-maximally Entangled W-Class State in Cavity QED

We propose an experimentally feasible teleportation scheme with three-atom W-class state, which was first proposed by Agrawal and Pati [P. Agrawal and A. Pati, Phys. Rev. A 74 (2006) 062320], in cavity QED. In this scheme atoms interact simultaneously with a nonresonant cavity and there is no energy exchange between the atoms and the cavity. Thus it is insensitive to the cavity decay, which is of importance in view of experiment.     

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.     

The Controlled Teleportation of an Arbitrary Two-Atom Entangled State in Driven Cavity QED

In this paper, we propose a scheme for the controlled teleportation of an arbitrary two-atom entangled state |φ〉₁₂=a|gg〉₁₂+b|ge〉₁₂+c|eg〉₁₂+d|ee〉₁₂ in driven cavity QED. An arbitrary two-atom entangled state can be teleported perfectly with the help of the cooperation of the third side by constructing a three-atom GHZ entangled state as the controlled channel. This scheme does not involve apparent (or direct) Bell-state measurement and is insensitive to the cavity decay and the thermal field. The probability of the success in our scheme is 1.0.     

利用三原子W类纠缠态在腔量子电动力学体系中实现单原子态的远程制备

提出了两个利用三原子W类纠缠态作为量子通道.在腔量子电动力学(QED)体系中实现单原子态的远程制备方案:一个是接收者借助于原子与单模腔场之间的大失谐相互作用实现初始态重建,另一个则是接受者利用原子与单模腔场之间的共振相互作用完成远程态制备.两方案中都涉及到了一位发送者和两位接收者,发送者可以将被传送态远程制备到两位接收者中的任何一位的手中,而另一位接受者必须为其提供必要的协助.表明利用原子与腔场之间的大失谐相互作用的方法可以很好地克服腔场的消相干,降低对腔品质因子的要求;而利用共振相互作用的方法则无需引入辅助原子,操作简便.但不论采用何种方法,实现单原子远程态制备的总成功概率是相同的.     

Scheme for Generating a Genuine Five-Atom Entangled State in Cavity QED

We propose a scheme for the generation of a genuine five-atom entangled state in cavity QED. In our scheme, the atoms interact simultaneously with a highly detuned cavity mode with the assistance of a strong classical driving field. Thus the scheme is insensitive to both the cavity decay and the thermal field, which is of importance from the experimental point of view.     

Alternative Scheme for Teleportation of Two-Atom Entangled State in Cavity QED

We have proposed an alternative scheme for teleportation of two-atom entangled state in cavity QED. It is based on the degenerate Raman interaction of a single-mode cavity field with a ∧-type three-level atom. The prominent feature of the scheme is that only one cavity is required, which is prior to the previous one. Moreover, the atoms need to be detected are reduced compared with the previous scheme. The experimental feasibility of the scheme is discussed.The scheme can easily be generalized for teleportation of N-atom GHZ entangled states. The number of the atoms needed to be detected does not increase as the number of the atoms in GHZ state increases.     

Preparing an Eight-Qubit Entangled State in Cavity QED

An experimental protocol for preparing an eight-qubit entangled state in cavity QED is proposed, which is insensitive to the cavity decay and the thermal field. And the experimental feasibility of our protocol is discussed.     

Alternative Scheme for Teleportation of Two-Atom Entangled State in Cavity QED

We have proposed an alternative scheme for teleportation of two-atom entangled state in cavity QED. It is based on the degenerate Raman interaction of a single-mode cavity field with a A-type three-level atom. The prominent feature of the scheme is that only one cavity is required, which is prior to the previous one. Moreover, the atoms need to be detected are reduced compared with the previous scheme. The experimental feasibility of the scheme is discussed. The scheme can easily be generalized for teleportation of N-atom GHZ entangled states. The number of the atoms needed to be detected does not increase as the number of the atoms in GHZ state increases.     

Quantum State Sharing of an Arbitrary Two-Atom State with a Genuine Six-Atom Entangled State in Cavity QED

We demonstrate that a genuine six-atom entangled state can be used to realize the deterministic quantum state sharing of an arbitrary two-atom state in cavity QED. In our scheme, any one of the two agents is sufficient to reconstruct the original state only under the condition that he/she obtains the help of the other one, but one of them obtains no information. The presented protocol is showed to be secure against certain eavesdropping attacks.     

Quantum State Sharing of an Arbitrary Single-Atom State by Using a Genuine Six-Atom Entangled State in Cavity QED

We demonstrate that a genuine six-atom entangled state can be used to realize the deterministic quantum state sharing of an arbitrary single-atom state in cavity QED. The scheme does not involve Bell-state measurement and is insensitive to both the cavity decay and the thermal field. In our scheme, any one of the two agents is sufficient to reconstruct the original state only under the condition that he/she obtains the help of the other one, but one of them obtains no information.     

Quantum Information Splitting of an Arbitrary Two-Atom State by Using a Genuinely Entangled Five-Atom State in Cavity QED

We demonstrate that a genuinely entangled five-atom state can be used to realize the deterministic quantum information splitting of an arbitrary two-atom state in cavity QED. The scheme does not involve Bell-state measurement and is insensitive to both the cavity decay and the thermal field. The presented protocol is showed to be secure against certain eavesdropping attacks.     

Scheme for Preparation of a Peculiar Type of Tripartite Entangled State via Thermal Cavity

We propose a simple scheme for the generation of a peculiar tripartite entangled state via thermal cavity. The peculiar tripartite entangled state shares features of the GHZ and 14/ state simultaneously. The photon-numberdependent parts in the effective Hamiltonian are canceled with the assistance of a strong classical field, thus the scheme is insensitive to both the thermal field and the cavity decay. The only thing one needs to do is to modulate the interaction time only once.     

利用腔QED技术控制传输任意两原子态

我们提出一个利用腔QED技术控制传输任意两原子态的方案.在此方案中,我们选择一个GHZ态和一个EPR对作为量子通道.在控制者的帮助下,发送者可以把量子信息传送给接收者.在传输过程中,两对原子分别与两个全同单模场相互作用,同时两对原子分别由两个全同经典场驱动.该方案对腔衰变和热场不敏感,并且传输成功的几率为1.     

Probabilistic Teleportation of an Arbitrary Two-Atom State in Cavity QED

We propose a scheme for the teleportation of an arbitrary two-atom state by using two pairs of two-atom nonmaximally entangled states as the quantum channel in cavity QED. It is Shown that no matter whether the arbitrary two-atom pure state to be teleported is entangled or not, our teleportation scheme can always be probabilistically realized. The success prohability of teleportation is determined by the smaller coemcients of the two initially entangled atom pairs.     

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.