Generation of multi-atom cluster states via an unconventional geometric phase shift in cavity QED

This paper proposes two schemes to generate the multi-atom cluster states. The first scheme is based on the interaction of atoms with a highly detuned cavity mode and a classical field, the second scheme is based on the interaction of atoms with a cavity mode, strongly driven by a resonant classical field.     

Generating Even-Photon State via Resonant Interaction Between Ladder-Type Three-Level Atoms with a Single-Mode Field

A scheme is presented to generate even-photon state based on resonant interaction between ladder-type three-level atoms with a single-mode field. In the scheme, a sequence of suitably prepared ladder-type three-level atoms are orderly sent through a single-mode cavity initiaJly in vacuum state. The detection of a J1 the atoms in the ground states collapses the cavity to the desired state. The scheme is based on the resonant interaction of atoms with the cavity, and thus the required interaction time can be greatly shortened. This is important in view of decoherence.     

Generation of any superposition of coherent states along a straight line via resonant atom-cavity interaction

This paper proposes a scheme for generating arbitrary superpositions of several coherent states along a straight line for a cavity mode. In the scheme, several atoms are sent through a cavity initially in a strong coherent state. The superposition of several coherent states with desired coefficients may be generated if each atom is detected in the excited state after it exits the cavity. The scheme is based on resonant atom--cavity interaction and no classical field is required during and after the atom--cavity interaction. Thus, the scheme is very simple and the interaction time is very short, which is important in view of decoherence.     

Nonclassical Properties in the Resonant Interaction of a Three Level A-type Atom with Two-mode Coherent state

A potential scheme is proposed to deterministically generate complete sets of entangled photons in the context of cavity quantum electrodynamics （QED）. The scheme includes twice interactions of atoms with cavities, in which the first interaction is made in two-mode optical cavities and the second one exists in a microwave cavity. In the optical cavities the atoms are resonant with the cavity modes, while the detuned interaction of the atoms with a singlemode of the microwave cavity is driven by a classical field. The favorable features of our scheme include ： （ 1 ） it is very straightforward in implementation because we carry out the scheme by only sending atoms through the cavities. The requirement for the implementation is very close to the reach of current cavity QED techniques. （2） The com- plete set of the entangled two- or more-photon states can be generated deterministically by our scheme, and the implementation time remains constant with the size of the entangled photon states. （3） Our scheme is more efficient than previous proposals with cavities, and the generated photons may be collected much more efficiently, due to cavities, than previous proposals by spontaneous emission.     

Teleportation of two-atom entangled state in resonant cavity quantum electrodynamics

An alternative scheme is presented for teleportation of a two-atom entangled state in cavity quantum electrodynamics (QED). It is based on the resonant atom--cavity field interaction. In the scheme, only one cavity is involved, and the number of the atoms needed to be detected is decreased compared with the previous scheme. Since the resonant atom--cavity field interaction greatly reduces the interaction time, the decoherence effect can be effectively suppressed during the teleportation process. The experimental feasibility of the scheme is discussed. The scheme can easily be generalized to the teleportation of N-atom Greeninger--Horne--Zeilinger (GHZ) entangled states. The number of atoms needed to be detected does not increase as the number of the atoms in the GHZ state increases.     

Generation of entangled coherent states for two cavity modes via resonant interaction with a V-type three-level atom

This paper proposes a scheme for the generation of entangled coherent states for two cavity modes. In the scheme a V-type three-level atom is sent through a two-mode cavity filled with a coherent field. After the atom cavity interaction and detection of the atomic state the cavity modes may evolve to a superposition of two-mode coherent states. As the scheme is based on resonant atom-cavity interaction, the required interaction time is short, which is important in view of the decoherence. Moreover, additional classical pulses are unnecessary before and after the atom-cavlty interaction.     

One-Step Generation of Cluster States Assisted by a Strong Driving Classical Field in Cavity Quantum Electrodynamics

We propose a scheme for one-step generation of cluster states with atoms sent through a thermal cavity with strong classical driving field, based on the resonant atom-cavity interaction so that the operating time is sharply short, which is important in the view of decoherence.     

Robust generation of high-fidelity entangled states for multiple atoms

A scheme is presented for generating entangled states of multiple atoms in a cavity. In the scheme the atoms simultaneously interact with a cavity mode, with the first atom driven by two classical fields and the other atoms driven by a classical field. Our scheme is valid even if the cavity decay rate is larger than the effective coupling strength, which is important for experiment. The generation of entangled states is conditional on the detection of a photon decaying from the cavity and thus the fidelity of the entangled state is insensitive to the detection inefficiency. Furthermore, the scheme can be applied to the case with any number of atoms in principle.     

Entanglement swapping without joint measurement via a Λ-type atom interacting with bimodal cavity field

This paper proposes a scheme for realizing entanglement swapping in cavity QED. The scheme is based on the resonant interaction of a two-mode cavity field with a ∧-type three-level atom. In contrast with the previously proposed schemes, the present scheme is ascendant, since the fidelity is 1.0 and the joint measurement isn＇t needed. And the scheme is experimentally feasible based on the current cavity QED technique.     

Efficient Scheme for Entangling Two Distant Atoms

A scheme is presented for the generation of entangled states for two atoms trapped in two distant cavities. In the scheme each atom is resonantly coupled with the respective cavity mode and driven by a strong classical field. The detection of a photon decaying from the cavities and passing through a beam-splitter collapses the atoms to an entangled state. The required atom-field interaction time is very short and thus the decoherence effect is suppressed. Our scheme is within the reach of presently available cavity QED techniques.     

Teleportation of atomic states with a weak coherent cavity field

A scheme is proposed for the teleportation of an unknown atomic state. The scheme is based on the resonant interaction of atoms with a coherent cavity field. The mean photon-number of the cavity field is much smaller than one and thus the cavity decay can be effectively suppressed. Another advantage of the scheme is that only one cavity is required.     

Strong-Driving-Assisted Probabilistic State Preparation in Cavity QED

An alternative scheme is proposed for preparing the superpositions of coherent states with controllable weighting factors along a straight line for a cavity field. The scheme is based on the interaction of a single-mode cavity field with a resonant two-level atom driven by a strong classical field. It is in contrast to the previous methods used in cavity QED of injecting a coherent state into a cavity via a microwave source. In the scheme, the interaction between the cavity mode and atoms is fully resonant, thus the required interaction time is greatly shortened. Moreover, the present scheme requires smaller numbers of operations. In view of decoherence, a reduction of interaction time and numbers of operations for the state preparation is very important for experimental implementation of quantum state engineering.     

Strong-Driving-Assisted Probabilistic State Preparation in Cavity QED

An alternative scheme is proposed for preparing the superpositions of coherent states with controllable weighting factors along a straight line for a cavity field. The scheme is based on the interaction of a single-mode cavity field with a resonant two-level atom driven by a strong classical field. It is in contrast to the previous methods used in cavity QED of injecting a coherent state into a cavity via a microwave source. In the scheme, the interaction between the cavity mode and atoms is fully resonant, thus the required interaction time is greatly shortened. Moreover, the present scheme requires smaller numbers of operations. In view of decoherence, a reduction of interaction time and numbers of operations for the state preparation is very important for experimental implementation of quantum state engineering.     

Teleportation of a Weak Coherent Cavity Field State

In this paper we propose a scheme to teleport a weak coherent cavity field state. The scheme relies on the resonant atom-field interaction inside a high-Q cavity. The mean photon-number of the cavity field is assumed much smaller than one, hence the field decay inside the cavity can be effectively suppressed.     

基于两原子同时和腔场共振作用制备两原子纠缠态的腔QED方案(英文)

我们提出了一个将两个远离的原子制备成纠缠态的腔QED方案,该方案基于两个原子同时和一个腔场发生共振作用.在这个方案里,我们利用一个事先制备好的纠缠态将另外两个分离的原子制备成纠缠态.该方案仅包含两个原子和腔场的共振相互作用,不需要用腔场存储量子信息,并且原子和腔场作用时间极短.因此,我们的方案基于目前的腔QED技术是可以实现的.     

利用双光子过程耦合腔系统实现量子信息转移

给出了利用两个二能级原子和耦合腔双光子过程相互作用系统实现量子信息转移的方案。该方案中二能级原子通过双光子跃迁与单模腔场发生共振相互作用。通过控制原子与光场的相互作用时间,实现量子信息从一个原子转移到另一个原子。     

在双光子Jaynes-Cummings模型中制备薛定谔猫态

提出一个制备光场具有可控制的权重因子的N+1个相干态的叠加态的方案.它是基于双光子共振相互作用中对通过腔中的原子进行选态测量.     

Preparation of Two atoms Entangled States via the Quantized Cavity Field Resonant Interaction with AtomSupported by the Young Core Teacher and Domestic Visitor Foundation of the Education Committee of Hunan Province.

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