Generation of Atomic Cluster State via Adiabatic Evolution of Dark Eigenstates

We propose a scheme to generate atomic cluster states of arbitrary configuration in the cavity quantum electrodynamics （QED） system. The process is achieved via adiabatic evolution of dark states, which only requires adiabatically increasing or decreasing Rabi frequencies of laser. Thus it allows the robust implementation of entanglement against certain types of errors. Our scheme is relatively decoherence-free in the sense that excited atomic states are never populated and excited cavity photon states can be made negligible in certain conditions.     

Generation of multiple-particle cluster state via cavity QED

This paper proposes schemes for generating multiple-photon and multiple-atom cluster states, respectively. The schemes are based on the cavity input-output process and atomic or photonic states measurement, and the successful probabilities approach unity in the ideal case. The numerical simulations show that the produced multiple-particle cluster states have high fidelity even if the Lamb-Dicke condition is not satisfied. Some practical imperfections, such as atomic spontaneous emission and output coupling inefficiency, only decrease the success probability but exert no influence on the fidelity of generated multiple-particle cluster states. From the experimental point of view, smaller operation number and lack of need for individual addressing keeps the schemes easy to implement. These schemes may offer a promising approach to the generation of a large-scale cluster state.     

Scheme for generating a cluster-type entangled squeezed vacuum state via cavity QED

A scheme is proposed to generate an N-qubit cluster-type entangled squeezed vacuum state （CTESVS） based on the two-photon interaction between a two-level atomand the cavity fields with the cavity QED system. The CTESVS in N separate cavities can be effectively obtained after performing a simple one-qubit measurement on the atom. The influence of cavity decay on the CTESVS is also discussed.     

Preparation of Cluster States for Many Atoms in Cavity QED

We propose a scheme for the generation of the cluster states for many atoms in cavity QED. In our scheme,the atoms are sent through nonresonant cavity fields in the vacuum states. The cavity fields are only virtually excited and no quantum information will be transferred from the atoms to the cavity fields. The advantage is that the cavities are suppressed during the procedure. The scheme can also be generalized to the ion trap system.     

基于腔QED制备W纠缠态

利用一个三能级原子与四个腔场之间相互作用研究双光子四粒子体系W态的制备,通过合适选择原子与腔场之间的相互作用时间可以获得该态的最大保真度以及成功几率     

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.