Dynamics of the Driven Jaynes-Cummings Model

We study the dynamical features of the Jaynes-Cummings model with the atomdriven by an external classical field in the case that the cavity field is initially in a Fock state.We find the dynamical variables by using dressed states in the bare atom representation. Weshow that the dynamical behavior of the cavity field can be strongly modified by the externalclassical field. We also find that the cavity field is super-Poissonian after some interaction timeif the external field is strong enough.     

Quantum Entropy Controlling in the Damping Jaynes-Cummings Model

The quantum entropy of the damping Jaynes-Cummings model is investigated in different decay coefficients under detuning conditions. The results indicate that the larger the decay coefficient is, the more quickly the entropy decays. The detuning of the atom and field frequencies reduce the entanglement maximum in short time regions, but delays the damping process of the entanglement. The sine modulation enhances the entanglement in short time regions.     

Influences of Detuning on Geometrical Quantum Discord Dynamics in Double Jaynes-Cummings System

We consider the case that the two-level atom off-resonantly interacts with cavity field via a one-photon hopping in double Jaynes-Cummings system. Geometrical quantum discord (GQD) is adopted to quantify the degree of correlation between two subsystems. GQD dynamics between two atoms, between cavity fields, as well as between atom and cavity fields are studied. The influences of detuning on GQD are discussed. The results obtained using the numerical method show that GQD between two atoms, between cavity fields, and between atom and cavity fields all display periodic oscillations. Furthermore, their periodic oscillations frequencies increase with the increase of detuning. On the other hand, GQD between two cavity fields and that between atom and cavity are weakened with increase of detuning.

     

Kerr介质中J-C模型的色散近似耗散动力学

应用全量子论研究了含Kerr介质的Jaynes-Cummings模型在色散近似下系统和子系统的相干性丢失及纠缠特性,在输入场为相干场假设下计算了线性熵.结果表明,原子相干性丢失与Kerr效应无关,场和原子-场系统的相干性丢失因Kerr介质的存在而增强,原子与场之间的纠缠因Kerr效应而受到压制,场的相干性时间演化规律在定性和定量两方面都受到腔耗的影响.Kerr介质对场线性熵的作用要通过腔耗才能展现出来.     

真空态多光子Jaynes—Cummings模型中场的非经典性

研究了一初始处于原子相干态的二能级原子与真空场相互耦合的多光子Jaynes-Cummings模型中辐射场展示的亚泊松分布,压缩和振幅平方压缩等非经典效应.     

频率变化场J-C模型中的量子态保真度

利用Jaynes-Cummings模型,考虑场频率受微扰的情况,在旋波近似下研究了二能级原子与单模辐射场相互作用系统中量子态保真度的演化.利用数值计算方法给出量子态保真度随时间的演化曲线.研究了场频率随时间正弦函数形式变化对系统、光场和原子的量子态保真度演化的影响.结果表明:场频率随时间正弦函数形式变化对系统和光场的量子态保真度的演化的影响很小,但对原子的量子态保真度的演化有显著影响.     

等同双原子Jaynes-Cummings模型的量子特性及系统光谱

在全量子理论的背景下提出两个二能级原子分别与一单模腔场相互作用的系统模型,利用量子主方程和数值模拟计算等方法,研究该体系中腔场平均光子数、Mandel's Q因子及二阶量子相关度在非稳态时的变化规律。此外,对体系中原子及腔场中光谱结构进行了分析。结果表明:减小腔场耗散系数,增大原子间耦合系数,体系量子特性愈加明显。体系光谱呈现出Mollow三重峰结构,且原子辐射谱强度远大于腔场辐射谱强度。当原子跃迁频率与腔场跃迁频率为近共振时,Mollow峰值为三峰中最大值。此外,增大原子与腔场间耦合系数,可增大原子光谱的中峰强度;而增大腔场光谱的中峰强度,则需减小原子与腔场间耦合系数。     

Dynamics of Information Entropies of Atom-Field Entangled States Generated via the Jaynes-Cummings Model

In this paper we have studied the dynamical evolution of Shannon information entropies in position and momentum spaces for two classes of(nonstationary)atom-field entangled states,which are obtained via the JaynesCummings model and its generalization.We have focused on the interaction between two-and(1)-type three-level atoms with the single-mode quantized held.The three-dimensional plots of entropy densities in position and momentum spaces are presented versus corresponding coordinates and time,numerically.It is observed that for particular values of the parameters of the systems,the entropy squeezing in position space occurs.Finally,we have shown that the well-known BBM(Beckner,Bialynicki-Birola and Mycielsky)inequality,which is a stronger statement of the Heisenberg uncertainty relation,is properly satisfied.     

类克尔介质光腔中原子的纠缠动力学研究

初始处于纠缠的原子与附加类克尔介质的光腔相互作用,运用共生纠缠的度量方法对原子间的纠缠演化动力学进行研究,分析了腔场粒子数、介质非线性效应及原子与腔场的失谐量对纠缠演化的影响,发现处于腔场真空态下原子间的纠缠作周期性震荡演化,而处在腔场粒子数态下的原子在演化过程中发生纠缠突然死亡现象;在非线性克尔介质作用下,处于腔场粒子数较小范围内(n≤5)的原子间也会产生纠缠突然死亡现象;但随着腔场粒子数的增加纠缠突然死亡现象消失而且一定程度上可以达到纠缠初始值;当腔场处于任意粒子数态时,由于非线性效应的影响,均可抑制纠缠突然死亡现象的发生;当腔场在没有类克尔介质作用时,原子与腔场间的失谐量同样可以避免纠缠突然死亡现象的发生.     

The Dynamics of Quantum Entanglement and General Quantum Correlations in the Double Tavis-Cumming Model

We study the dynamics of quantum correlations involving entanglement and discord of two pairs of two-level atoms in cavity QED. In the model, two atoms A and C are coupled with a single-mode cavity field via Tavis-Cumming interaction at one location, and the same for B and D at another location. The two locations are connected by the entanglement of the atoms AB and CD while there are no any direct interactions between them. Through comparing the robustness of entanglement and discord of the atoms in various initial conditions of cavities, it is shown the discord is more robust than the entanglement and would be useful in quantum information technology.     

Sensitive Response of the Quantum Entropies to Jaynes-Cummings Model in Presence of a Second Harmonic Generation

The behavior of a modified Jaynes-Cummings Hamiltonian model (two-level atom in interaction with an electromagnetic field) in the presence of degenerate parametric amplification is introduced. We have examined two different cases, one when the field frequency ω is not equal to the splitting photon frequency ε for which the off-resonance case is considered. In the second case we have taken each frequencies to be equal (ω = ε) and considered the system to be at exact resonance. The wave function for both cases is obtained and the result used to calculate the density matrix from which we manage to discuss the field entropy as well as the phase entropy. It is shown that the system is sensitive to any change in the splitting photon frequency ε.     

与压缩真空相互作用的具有强度耦合的广义Jaynes-Cummings模型的相位动力学

考虑具有强度耦合的广义Jaynes-Cummings模型与压缩真空相互作用.根据Pegg和Barnett新的相位理论,不仅得到了压缩真空场的相位分布,相位期待值和相位涨落的普遍表示式,及其演化图示,而且还导出了弱压缩真空和强压缩真空情形的近似角析表示式.对于压缩真空的压缩量与相位特性之间的关系进行了简要讨论.     

Nonlinear Quantum Optical Springs and Their Nonclassical Properties

The original idea of quantum optical spring arises from the requirement of quantization of the frequencyof oscillations in the Hamiltonian of harmonic oscillator. This purpose is achieved by consideringa spring whose constant (and so its frequency) depends on the quantum states of another system.
Recently, it is realized that by the assumption of frequencymodulation ofω toω(1+μa^\dagger a)^1/2the mentioned idea can be established.
In the present paper, we generalize the approach of quantum optical springwith particular attention to thedependence of frequency to the intensity of radiation fieldthatnaturally observes in thenonlinear coherent states}, from which we arrive ata physical system has been called by us as nonlinear quantum optical spring.Then, after the introduction of the generalized Hamiltonian of nonlinear quantum optical spring and it's solution,we will investigate the nonclassical properties of the obtained states. Specially, typical collapse and revivalin the distribution functions and squeezing parameters, as particular quantum features, will berevealed.     

Entanglement Dynamics in a Model Tripartite Quantum System

A Λ-type atom interacting with two radiation fields exhibits electromagnetically induced transparency and other nonclassical effects that appear in the entanglement dynamics of the atomic subsystem and in appropriate field observables. Both EIT and field-atom entanglement are important for quantum information processing. We investigate the roles played by specific initial field states, detuning parameters, field nonlinearities and intensity-dependent field-atom couplings on EIT and the entanglement between subsystems. Departure from coherence of the initial field states produces significant effects. We investigate these aspects in a model that exhibits the salient features of entangled tripartite systems. For initial photon-added coherent states, collapses and revivals of the atomic subsystem von Neumann entropy appear as the intensity parameter varies over a narrow range of values. These features could be useful in enabling entanglement.     

Nonclassical Field States in Quantum Optics and Particle Physics

The primary aim of the present paper is to draw the attention of particle physicists to new developments in studying squeezed and correlated states of the electromagnetic field, and those working on the latest developments to new findings about multiplicity distributions and other specific effects in quantum chromodynamics. New types of nonclassical states used in quantum optics such as squeezed states, correlated states, and even and odd coherent states (Schrödinger cat states) for one-mode and multimode interactions are reviewed. Their distribution functions are analyzed according to the method first used for multiplicity distributions in high-energy particle interactions. The phenomenon of oscillations of particle distribution functions of squeezed fields is described and related to the phenomenon of oscillations of cumulant moments of some distributions for squeezed and correlated field states. Possible extension of the method to fields different from the electromagnetic field (gluons, pions, etc.) is conjectured, and some predictions of specific effects in nucleus-nucleus interactions at high energies are presented.     

失谐量对多模场非简并多光子Jaynes-Cummings模型量子场熵演化的影响

利用Von Neumann约化熵理论研究了多模相干态场与二能级原子非简并多光子相互作用系统中量子场熵的时间演化特性,得到了含有失谐量的多模场熵的解析表达式,并通过数值计算讨论了光场为三模场时频率失谐量对场熵演化的影响.结果发现：当近共振时,失谐量几乎不影响场与原子之间的纠缠特性;而当远离共振时,量子场熵很强地依赖于失谐量的大小,特别是当失谐量足够大时,场与原子几乎总是处于纠缠态.     

依赖于时间和强度耦合Jaynes-Cummings模型中原子的量子特性

本文研究了依赖于时间和强度耦合Jaynes-Cummings模型中原子的动力学行为.详细讨论了脉冲宽度和腔场强度对原子能级布居数反转的影响.