Generation of Four-Photon Coherent State via Degenerate Raman Interaction

A scheme is presented for generating a four-photon coherent state via the degenerate Raman interaction. The scheme does not need classical fields to manipulate the atoms. Its another advantage is that the atomic spontaneous emission can be neglected. Therefore, the coherence of the system may be better maintained. The scheme can be generalized to generate superposition of 2ⁿ coherent states and superposition of 2ⁿ two-mode coherent states. The coherent states in each mode are on a circle symmetrically.     

Deterministic generation of entangled coherent states for two atomic samples

This paper proposes an efficient scheme for deterministic generation of entangled coherent states for two atomic samples. In the scheme two collections of atoms are trapped in an optical cavity and driven by a classical field. Under certain conditions the two atomic samples evolve from an coherent state to an entangled coherent state. During the interaction the cavity mode is always in the vacuum state and the atoms have no probability of being populated in the excited state. Thus, the scheme is insensitive to both the cavity decay and atomic spontaneous emission.     

Preparation of Highly Squeezed States and Multi—component Entangled Coherent States via the Raman Interaction

A method is presented for generating highly squeezed states of a cavity field via the atom-cavity field interaction of the Raman type.In the scheme a sequence of three-level Λ-type atoms interacts with a cavity field,displaced by a classical source,in a Raman manner.Then the atomic states are measured.By this way the cavity field may collapse onto a superposition of several coherent states,which exhibits strong squeezing.The scheme can also be used to prepare superpositions of many two-mode coherent states for two cavity fields.The coherent states in each mode are on a straight line.This is the first way for preparing multi-component entangled coherent states of this type in cavity QED.     

Generation of Entangled Bloch States for Two Atomic Samples Trapped in Separated Cavities

A scheme is presented for the cavities. In the scheme, each a coherent state with a small generation of entangled states for two atomic ensembles trapped in two distant atomic sample is initially in a Bloch state and the cavity mode is initially in amplitude. The dispersive dependent phase shift on the atomic system. The detection atomic samples collapse to an entangled Bloch state. atom-cavity interaction leads to a photon-number of a photon leaking from the cavities makes the two     

Engineering two-mode squeezed states of cold atomic clouds with a superconducting stripline resonator

A scheme is proposed for engineering two-mode squeezed states of two separated cold atomic clouds positioned near the surface of a superconducting stripline resonator. Based on the coherent magnetic coupling between the atomic spins and a stripline resonator mode, the desired two-mode squeezed state can be produced via precisely control on the dynamics of the system. This scheme may be used to realize scalable on-chip quantum networks with cold atoms coupling to stripline resonators.     

A Scheme for Generating Cluster States via Raman Interaction

A scheme for generating cluster states via Raman interaction is proposed. In the scheme, we firstly prepare cluster states of multi-cavities with information encoded in the coherent states and then generate cluster states of multiatoms, which encode the information in the ground states of A-type atoms. The advantages of our scheme are that the atomic spontaneous radiation can be efficiently reduced since the cavity frequency is largely detuned from the atomic transition frequency and the Hadamard gate operation of the coherent states is replaced by measuring the coherent states.     

Teleportation of Unknown Superpositions of Collective Atomic Coherent States

We propose a scheme to teleport an unknown superposition of two atomic coherent states with different phases.Our scheme is based on resonant and dispersive atom-field interaction.Our scheme provides a possibility of teleporting macroscopic superposition states of many atoms first time.     

含原子运动的Jaynes-Cummings模型中的量子态保真度

研究了相干光场作用下的含原子运动的Jaynes-Cummings模型中体系量子态保真度,讨论了不同的原子初态条件下,原子的运动和场模结构对体系中的量子态保真度的影响。结果表明：在一定的条件下,原子运动的速度和场模结构参数可调制相互作用体系的量子态保真度。     

Photoionization properties of an atom with two autoionizing states

We have investigated the photoionization properties of an atom with a ladder coupling scheme involving two autoionizing states coupled to each other.The effects of the coherent coupling between two autoionizing states and between the low-lying autoionizing state and the continuum on the ionization yield are discussed.The conditions leading to atomic coherent population trapping and the coherent population trapping states are given explicitly.     

Quantum Teleportation via Hybrid Entangled States

In this paper, we study quantum teleportation of atomic states via a hybrid entangled state (HES) involving an atom and a cavity field. And we investigate how to implement controlled phase (CP) gates between atomic internal states and coherent states of cavity field. We also discuss the methods of distinguishing coherent states |±α〉in a cavity. Finally, a brief discussion about the feasibility of this scheme in experiment is presented.     

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.     

Scheme for Preparation of Macroscopic Multi-component Entanglement in Cavity QED

We propose a scheme of generating multi-component entangled coherent states of cavity fields. In this scheme, the atoms pass through cavities one by one, simultaneously driven by a strong classical field in each cavity. Then the detection of the atomic states collapses the cavity fields onto multi-component entangled coherent states. It is shown that, with a judicious choice of the parameters of the classical field, we can conditionally produce macroscopic multi-dimensional maximal entanglement for the cavity modes.     

通过Raman相互作用制备三个腔场的W型纠缠相干态

通过对比分立变量量子信息过程和连续变量量子信息过程的差别,利用相干态比较容易获得的这个特点,提出一种方案制备三个腔场的W型纠缠相干态.方案基于Λ型三能级原子与单模腔场的简并Raman 相互作用.三个相同的腔初始分别处于相干态,三个相同的原子初始处于W型纠缠态,通过三个原子分别与三个腔的Raman相互作用、选择适当的相互作用时间并探测作用后的三个原子,三个腔场坍缩为W型纠缠相干态.在原子与腔的相互作用过程中原子不处于高能级,可以忽略原子的自发辐射,系统的相干性能够得到较好的维持.基于当前的腔量子电动力学技术,相信方案能在实验上实现.该方案制备的三个腔场W型纠缠相干态有望在连续变量量子信息过程中有重要的应用价值.文中将方案推广到制备n(n〉3)个腔场的W型纠缠相干态.     

Generation of Superpositions of Atomic Coherent States Through Raman Atom-Field Interaction

We propose a scheme for the generation of superpositions of collective atomic coherent states. In the scheme a collection of degenerate A-type three-level atoms is confined in a high-Q cavity and interacts with the cavity field in a Raman manner. Then a state reduction on the field collapses the atomic system onto a superposition state.     

压缩相干态腔场的类自旋GHZ态的制备

压缩相干态是准粒子空间的相干态,研究大振幅情况下的单模压缩相干态腔场,其特性类似于大振幅下的单模相干态腔场,与自旋1/2的两态粒子同构.文中提出一种方案,利用大失谐的JaynesCummings模型来制备处于压缩相干态的三个腔场的类自旋GreenbergerHorneZeilinger(GHZ)态. 关键词： 压缩相干态 类自旋GHZ态 大失谐JaynesCumminys模型 同构     

Generation of Quantum States for Atomic Ensemble via Cavity QED

A scheme is proposed for generating quantum states of atomic ensemble. In this scheme, a beam of three-level atoms in the Λ configuration is trapped in a cavity, then squeezed vacuum state and squeezed coherent state of the atomic ensemble are prepared by choosing different initial states of the system. The scheme is based on the off-resonant interaction between the atom and cavities, so the high-level of the atom is eliminated adiabatically.     

Generation of Cluster States in Cavity QED

We propose two schemes for the generation of cluster states in the context of cavity quantum electrodynamics （QED）. In the first scheme, we prepare multi-cavity cluster states with information encoded in the coherent states. The second scheme is to generate multi-atom cluster states, where qubits axe represented by the states of cascade Rydberg atoms. Both the schemes axe based on the atom-cavity interaction and the atomic spontaneous radiation can be efficiently reduced since the cavity frequency is largely detuned from the atomic transition frequency.     

Preparation of nonclassical states and measurement of the Wigner function for the collective motion of N trapped ions

We propose a scheme for generating nonclassical states for the centre-of-mass vibrational mode of N trapped ions,including superpositions of several coherent states on a circle and Fock states. In the scheme N trapped ions are driven by a laser beam tuned to the carrier. The scheme also provides a new prospect for laser cooling. The scheme can be used to measure the Wigner function of the collective vibrational mode.     

纠缠相干态的制备

在非线性克尔介质和光场的相互作用基础之上,提出了一个纠缠相干态(包括多模和高模纠缠)的光学实现方案。发现通过适当选择场的初态,相互作用时间和广义贝尔测量,能产生多模和高维纠缠相干态。同时发现当输入模的态为相干态和叠加数态的情况下,非线性克尔相互作用可产生纠缠。     

可控制权重因子的原子纠缠态的制备

提出了一种利用二能原子与相干态腔场的非共振相互作用制备原子纠缠态的方案。在一定条件下,获得了可控制权重因子的原子纠缠态以及纠缠两原子的4个贝尔基。