论Jsynes-Cummings模型中原子偶极压缩和光场压缩间的关联

通过考察单光子Jaynes-Cummings(J-C)模型和非简并双光子J-C模型中原子偶极压缩和光场压缩随时间演化的规律,研究了原子偶极压缩与光场压缩之间的关系,给出了处于偶极压缩状态的原子辐射压缩光的条件,并讨论了原子压缩分量与光场压缩分量之间相互转化的特征,指出了原子-光场间的双光子耦合系统比单光子耦合系统更有利于制备压缩程度深的压缩光.     

失谐量对双光子J-C模型中光场位相扩散及频率漂移的影响

通过考察失谐量对双光子Jaynes-Cummings(J-C)模型中光场位相的影响,论证了失谐量不仅会影响原子-光场耦合程度,而且还会导致光场频率发生漂移.并且讨论了双光J-C模型中光场位相特性与双光子激光频率特性之间的关系.     

双相干态光场与原子依赖强度耦合过程的腔场谱

研究了依赖强度耦合双模J-C模型的腔场谱,给出了激发态原子与双相干态光场双光子共振相互作用过程光谱结构的数值结果.发现腔场谱呈现出复杂的多峰结构.腔场谱的频率灵敏地受两模光子数差q的调谐.     

阻尼Jaynes-Cummings模型中两原子的量子关联动力学

几何量子失协 (geometrical quantum discord, GQD)是目前度量量子体系中量子关联的一种行之有效的方法, 本文利用几何量子失协考察了有阻尼存在的Jaynes-Cumming (J-C)模型中两原子的量子关联动力学. 给出了几何量子失协在原子和光场发生共振和非共振耦合两种情况下的动力学演化行为, 尤其揭示了阻尼耗散对几何量子失协的影响. 关键词： 阻尼Jaynes-Cummings(J-C) 模型 量子关联 几何量子失协 (GQD)     

Kerr介质腔中非线性J-C模型的腔场谱

研究了Kerr介质腔中非线性J-C模型的腔场谱.导出了初始光场处于任意量子态时腔场谱的计算公式,给出了光场处于数态、相干态和压缩真空态时的数值结果,讨论了Kerr效应和初始场强对腔场谱的影响.发现在光子数态的情况下,n≠1时均为2峰结构,Kerr介质使得中心频率按x(2n-1)的规律向高频方向移动,并破坏谱结构的双峰对称性;在相干态和压缩真空态情况下,当Kerr效应较弱时,非线性J-C模型中腔场谱的非经典特性较为突出,Kerr效应较强时,呈现多峰结构,谱的结构特征主要由Kerr效应决定,由于原子与腔场的耦合被抑制,腔场谱的非线性特征趋于消失.     

利用原子与光场的非最大纠缠态传送薛定谔猫态

利用二能级原子与腔场的共振相互作用Jaynes-Cummings(J-C)模型，制备出原子与光场的纠缠态，通过改变相互作用时间，可以控制纠缠态的纠缠程度。提出了利用这个原子与光场的非最大纠缠态，通过大失谐的J-C模型传送腔场的薛定谔猫态的方案。     

光场诱导的原子激光的量子相干性

基于伞量子理论,分别研究了几种重要的光场作用下,从原子玻色-爱因斯坦凝聚(BEC)体耦合输出的原子激光的量子相干特性.结果表明,粒子数态光场诱导的原子激光总是反聚束的,相干态光场诱导的原子激光是任意阶相干的,而压缩相干态光场诱导的原子激光总是聚束的.表明用光场诱导产生的原子激光具有与初始光场完全相间的量子相干性质.     

级联三能级原子与单模场相互作用下的腔场谱

研究了高Q腔内级联三能级原子与单模光场相互作用模型的腔场谱.结果表明,原子初态处于上能级时，随R=g2/g1的增大,真空场的拉比峰个数按2→6→4→2→4的规律变化，在R1时，所有的拉比峰都消失.在初始场较弱时,腔场谱可出现3峰、5峰或7峰.在初始场很强时,腔场谱中只有单一的经典共振峰.如果原子初态处在中能级且R=1,腔场谱为简单的对称双峰结构，与标准J-C模型的谱相似. 关键词： 级联三能级原子 单模光场 腔场谱     

两个双能级原子与辐射场的喇曼相互作用

研究了两个双能级原子与单模辐射腔场的喇曼相互作用。分别计算了两个原子与光场之间具有不同耦合常数和两个原子虽与光场具有相同耦合常数但同时考虑了原子间偶极-偶极相互作用两种情形下的辐射谱。分析了两个原子与辐射场之间耦合常数的相对大小和两原子间偶极作用的计入对辐射谱的影响。 关键词：     

原子在压缩光场中的共振辐射

本文应用随机统计理论方法获得了一二能级原子系综在多模压缩光驱动下的共振辐射光谱。对应于光场起伏的不同压缩程度,辐射光谱的中峰出现亚自然线宽与超自然线宽现象。它的边峰在任意情况下都被展宽,而且当光场起伏的压缩方向与光场振幅的相干激发方向不平行或不垂直时,辐射光谱均呈现不对称分布。 关键词：     

The physical transient spectrum for a V-type three-level atom interacting with a binomial field via multi-photon process and nonlinearities

We study the interaction of a multi-photon three-level atom with a single mode field in a cavity, taking explicitly into account the existence of forms of nonlinearities of both the field and the intensitydependent atom-field coupling. The analytical form of the emission spectrum is calculated using the dressed states of the system. The effects of photon multiplicities, mean photon number, detuning, Kerr-like medium, and the intensity-dependent coupling functional on the emission spectrum are analyzed.     

Entanglement of a General Formalism V-Type Three-Level Atom Interacting with a Single-Mode Field in the Presence of Nonlinearities

We investigate the evolution of the atomic quantum entropy and the atom-field entanglement in a system of a V-configuration three-level atom interacting with a single-mode field with additional forms of nonlinearities of both the field and the intensity-dependent atom-field coupling. With the derivation of the unitary operator within the frame of the dressed state and the exact results for the state of the system we perform a careful investigation of the temporal evolution of the entropy. A factorization of the initial density operator is assumed, considering the field to be initially in a squeezed coherent or binomial state. The effects of the mean photon number, detuning, Kerr-like medium and the intensity-dependent coupling functional on the entropy are analyzed.     

Population Dynamics and Emission Spectrum of a Cascade Three-Level Jaynes-Cummings Model with Intensity-Dependent Coupling in a Kerr-like Medium

By using the method of eigenvectors, the atomic populations and emission spectrum are investigated in a system that consists of a cascade three-level atom resonantly interacting with a single-mode field in a Kerr-like medium.The atom and the field are assumed to be initially in the upper atomic state and the Fock state, respectively. Results for models with intensity-dependent coupling and with intensity-independent coupling are compared. It is found that both population dynamics and emission spectrum show no indications of atom-field decoupling in the strong field limit if the intensity-dependent coupling is taken into account.     

Emission and absorption spectra of a Λ type three-level atom driven by a two-mode cavity field with nonlinearities

An analytical expression of the emission and absorption spectra for a Λ type three-level cavity-bound atom interacting with a two-mode cavity field is given using the dressed states of the system. We take into account explicitly the nonlinearities of both the field and the intensity-dependent atom-field coupling. The characteristics of the emission and absorption spectra when one of the two-mode cavity fields is in a binomial state and the other is in a squeezed coherent state are exhibited. The effects of the mean number of photons, detuning, and the kinds of nonlinearities on the spectra are analyzed.     

Treatment of the emission and absorption spectra for a Λ-type three-level atom driven by a single-mode field with nonlinearities

The treatment of a Λ-type three-level atom interacting with a single mode field in a cavity, explicitly taking the existence of forms of nonlinearities of both the field and the intensity-dependent atom-field coupling into account. Analytical expressions of the emission and absorption spectra are presented using the dressed states of the system. The characteristics of the emission and absorption spectra for binomial state and squeezedcoherent state inputs are exhibited. The effects of the mean number of photons, the detuning, and the nonlinearities on the spectra are investigated. It is shown that the features of the fluorescence and absorption spectra are influenced significantly by the kinds of nonlinearities.     

A treatment of the emission and absorption spectra of a general formalism V-type three-level atom driven by a single-mode field with nonlinearities

A treatment of a V-type three-level atom interacting with a single mode field in a cavity, taking explicitly the existence of forms of nonlinearities of both the field and the intensity-dependent atom-field coupling into account. Analytical expressions of the emission and absorption spectra are presented using the dressed states of the system. The characteristics of the emission and absorption spectra for a binomial state and a squeezed coherent state inputs are exhibited. The effects of the mean number of photons, detuning and the nonlinearities on the spectra are investigated. It is shown that features of the fluorescence and absorption spectra are influenced significantly by the kinds of the nonlinearities.     

原子运动和场模结构对原子动力学特性的影响

研究了双光子Jaynes-Cummings(J-C)模型中原子的动力学特性,讨论了在不同初态下,原子运动和场模结构对体系中原子反转的演化特性及原子偶极矩k阶压缩的影响.研究结果表明,原子的动力学特性不仅决定于原子和场的初态参量,而且通过时间因子g^Θ(t)=2^-1gt-(4_p)^-1sin(2_pgt)决定于原子的运动速度与场模结构参量.     

Entanglement Dynamics of Linear and Nonlinear Interaction of Two Two-Level Atoms with a Quantized Phase-Damped Field in the Dispersive Regime

In this paper we study the linear and nonlinear (intensity-dependent) interactions of two two-level atoms with a single-mode quantized field far from resonance, while the phase-damping effect is also taken into account. To find the analytical solution of the atom-field state vector corresponding to the considered model, after deducing the effective Hamiltonian we evaluate the time-dependent elements of the density operator using the master equation approach and superoperator method. Consequently, we are able to study the influences of the special nonlinearity function \(f (n) = \sqrt {n}\), the intensity of the initial coherent state field and the phase-damping parameter on the degree of entanglement of the whole system as well as the field and atom. It is shown that in the presence of damping, by passing time, the amount of entanglement of each subsystem with the rest of system, asymptotically reaches to its stationary and maximum value. Also, the nonlinear interaction does not have any effect on the entanglement of one of the atoms with the rest of system, but it changes the amplitude and time period of entanglement oscillations of the field and the other atom. Moreover, this may cause that, the degree of entanglement which may be low (high) at some moments of time becomes high (low) by entering the intensity-dependent function in the atom-field coupling.     

Engineering entanglement of a general three-level system interacting with a correlated two-mode nonlinear coherent state

In this article a treatment of a three-level atom interacting with two modes of light in a cavity with arbitrary forms of nonlinearities of both the fields and the intensity-dependent atom-field coupling is presented. A factorization of the initial density operator is assumed, with the privileged field modes being in a pair-coherent state. We derive and illustrate an exact expression for the time evolution of the density operator, by means of which we identify and numerically demonstrate the region of parameters where significantly large entanglement can be obtained. We show that entanglement can be significantly influenced by different kinds of nonlinearities. The nonlinear medium yields the superstructure of atomic Rabi oscillation. We propose a generation of Bell-type states having a simple initial state preparation of the present system. Received 29 July 2002 / Received in final form 18 October 2002 Published online 21 January 2003 RID="a" ID="a"e-mail: abdelaty@uni-flensburg.dePresent address: Institut für Mathematik, Universit?t Flensburg, Germany.     

Emission and absorption spectra of a general formalism Ξ-type three-level atom driven by a single-mode field with nonlinearities

We study the interaction of a three-level atom with a single-mode field in a cavity. We take explicitly into account the existence of the forms of nonlinearities of both the field and the intensity-dependent atom-field coupling. The wavefunction for the atomic system of the Ξ configuration is obtained when the atom is initially prepared in the excited state. The electromagnetic field may assume a squeezed coherent or binomial state. The analytical forms of the fluorescence and absorption spectra are calculated using the dressed states of the system. We investigate the influences of the mean number of photons, detunings, and the nonlinearities forms on the spectrum of the resulting field states. It is shown that the features of the fluorescence and absorption spectra are influenced significantly by the kinds of nonlinearities.