Kerr效应和虚光场对"两个二能级原子-单模光场"系统光子统计演化特性的影响

研究Kerr介质中,非旋波近似下两个二能级原子与单模光场相互作用的平均光子数的时间演化规律,讨论了Kerr效应和虚光场效应对系统光子统计演化特性的影响.结果表明虚光场的影响使系统出现量子噪声,光场频率ω、Kerr介质常量μ和原子间耦合系数g的增大都将使量子噪声减小;原子间耦合系数g和Kerr介质常量μ的增大使光子统计演化的拉比振荡的振幅变小.     

Kerr介质中级联型三能级原子与压缩相干光场相互作用系统的粒子布居几率

利用相互作用绘景，采用完全量子化理论，研究了充满Kerr介质的高Q腔中级联型三能级原子与压缩相干态光场相互作用系统粒子布居几率的时间演化规律；讨论了Kerr介质强度系数、光场压缩因子和光场相干振幅分量模平方对粒子布居几率的影响，结果发现：Kerr介质强度系、光场压缩因子和光扬相干振幅分量模平方都直接影响了粒子布局几率演化曲线的量子崩塌－复苏的周期性和Rabi振荡频率，而非线性的Kerr介质的存在会削弱光场与原子的相互作用；当场与原子的初始相互作用和Kerr效应增加到一定程度时，都会导致光场与原子的关联程度逐渐减弱直到至退耦。     

Kerr介质中耦合双原子与压缩相干态光场相互作用的光子统计演化

在相互作用绘景中，采用全量子化理论，研究了充满Kerr介质的高Q腔中两个耦合二能级原子与压缩相干态光场相互作用系统的光子统计演化规律；讨论了Kerr介质、光场相干振辐分量和压缩参量以及原子间耦合系数对系统平均光子数演化规律的影响。     

类Kerr介质中双模SU(1,1)相干态场与四能级原子相互作用中的场熵演化

利用类Kerr介质中双模SU(1，1)相干态场与四能级原子相互作用系统的态函数导出了场熵的计算公式，研究了Kerr效应和初始光场强度对场熵演化的影响。     

非线性Jaynes-Cummings模型中原子与光场的纠缠特性

利用密度矩阵的部分转置矩阵负本征值,研究了附加Kerr介质依赖强度耦合Jaynes-Cummings模型中原子与光场纠缠度随时间的演化特性,讨论了Kerr介质与不同初始光场对原子—光场纠缠度的影响.结果表明:原子—光场纠缠度随时间作周期性演化,其演化周期由光场与原子耦合强度以及光场与介质相互作用强度来确定,并随耦合强度和相互作用强度的增加而减小,其纠缠程度会随光场的初始状态的不同而产生明显的变化.     

Kerr介质中"Λ"型三能级原子与压缩相干态光场相互作用系统的光子统计分布特性

该文利用相互作用绘景,研究了充满Kerr介质的高Q腔中"Λ"型三能级原子与压缩相干态光场相互作用系统的光子统计分布特性的时间演化规律;讨论了Kerr介质强度系数μ、光场压缩因子γ、光场相干振幅分量模平方|α|2和原子-场的耦合系数λ对光子统计分布特性的影响.结果发现:μ、γ、|α|2和λ都影响了Mandel因子Q(t)的量子崩塌-复苏效应的周期性,同时,也影响了辐射场的光子统计分布的状态和特性.     

Kerr介质中耦合双原子与场相互作用的原子占居态几？…

研究了类克尔介质中初始时刻分别处于激发态和基态的耦合双原子与场相互作用过程,原子占居几率的量子动力学性质：讨论了Ｋｅｒｒ介质－场耦合系数μ、原子间偶极－偶极相互作用的耦合系数ｇａ及激发场强ｎ对它的影响。     

Kerr介质中双模纠缠相干光场与Bell态原子相互作用系统的原子布居数演化

运用全量子理论和数值计算方法, 研究Kerr介质腔中处于Bell态的两个全同二能级纠缠原子与双模纠缠相干光场相互作用系统的原子布居数演化特性. 讨论了双原子体系的初态、 初始光场的平均光子数、 双模纠缠相干光场的纠缠程度及Kerr介质与双模光场的耦合强度对原子布居时间演化特性的影响. 结果表明, 当双原子体系的初态为|β₁₁〉时, 原子布居均不随时间变化; 当双原子体系的初态为|β₀₀〉,|β₀₁〉或|β₁₀〉且初始平均光子数达到一定值时, 演化特性呈现周期性的崩塌-回复效应, 并随初始光子数的增加, 其演化曲线的振荡频率增大, 振幅减小; 双模纠缠相干光场的纠缠程度不影响Rabi振荡频率, 但对振幅影响显著; Kerr介质与光场耦合系数达到一定值时, 对Rabi振荡频率和幅度及原子布居的崩塌-回复周期产生强烈影响.      

非Jaynes-Cummings模型下二能级系统随时间演化问题的研究

应用相干态近似方法研究了与单模玻色子耦合的二能级系统 ,计算了该系统下的能量占有几率Pi(t) ,并且在各种不同的条件下与Jaynes Cummings模型计算出的结果进行了比较 .通过比较得出 :当J C模型已经不再适合的条件下 ,相干态近似方法仍可以用于处理二能级系统 .当考虑到占有几率Pi(t)的微分效应时 ,相干近似方法能够提供更好的近似结果 .相干态近似方法是一种非微扰的非变分的近似方法 ,可以通过提高近似的阶次来满足对数据精度的要求     

Kerr介质中“∧”型三能级原子与压缩相干态光场相互作用系统的光子统计分布特性

该文利用相互作用绘景，研究了充满Kerr介质的高Q腔中“∧”型三能级原子与压缩相干态光场相互作用系统的光子统计分布特征性的时间演化规律；讨论了Kerr介质强度系数ц、光场压缩因子γ、光场相干振幅分量模平方|α|^2和原子-场的耦合系数λ对光子统计分布特性的影响。结果发现：ц、γ、|α|^2和λ都影响了Mandel因子Q(t)的量子崩塌-复苏效应的周期性，同时，也影响了辐射场的光子统计分布的状态和特性。     

依赖强度耦合JC模型的原子动力学

本文研究了依赖强度耦合ＪＣ模型中二能级原子的动力学行为，着重讨论了初始光场分别为Ｇｌａｕｂｅｒ相干态和ＳＵ（１，１）相干态时原子初态、失谐量以及平均光子数对原子反转的影响。     

Kerr效应对双光子J-C模型中光场和原子偶极的压缩效应的影响

研究了一充满Kerr介质的高Q腔中双光子J-C模型中光场和原子偶极的压缩效应,指出了腔中Kerr效应对它们的不同影响。     

激光金等离子体中Au50+的光谱跃迁和能级寿命的相对论多组态计算

根据扩展的相对论多组态Dirac-Fock理论，采用“多功能相对论原子结构程序（GRASP2）”，计算了类铜金Au^50 的能级寿命和能级宽度及光谱跃迁波长、跃迁几年和振子强度，分析了轨道极化对能级的影响，指出了Au^50 离子内部的确存在轨道极化现象。计算所得波长值与实验值符合较好，能级寿命与能级宽度的大小关系符合海森堡的能量与时间测不准原理。     

Observation of coherent optical information storage in an atomic medium using halted light pulses

Electromagnetically induced transparency is a quantum interference effect that permits the propagation of light through an otherwise opaque atomic medium; a 'coupling' laser is used to create the interference necessary to allow the transmission of resonant pulses from a 'probe' laser. This technique has been used to slow and spatially compress light pulses by seven orders of magnitude, resulting in their complete localization and containment within an atomic cloud. Here we use electromagnetically induced transparency to bring laser pulses to a complete stop in a magnetically trapped, cold cloud of sodium atoms. Within the spatially localized pulse region, the atoms are in a superposition state determined by the amplitudes and phases of the coupling and probe laser fields. Upon sudden turn-off of the coupling laser, the compressed probe pulse is effectively stopped; coherent information initially contained in the laser fields is 'frozen' in the atomic medium for up to 1 ms. The coupling laser is turned back on at a later time and the probe pulse is regenerated: the stored coherence is read out and transferred back into the radiation field. We present a theoretical model that reveals that the system is self-adjusting to minimize dissipative loss during the 'read' and 'write' operations. We anticipate applications of this phenomenon for quantum information processing.     

Quantum nonlinear optics with single photons enabled by strongly interacting atoms

The realization of strong nonlinear interactions between individual light quanta (photons) is a long-standing goal in optical science and engineering, being of both fundamental and technological significance. In conventional optical materials, the nonlinearity at light powers corresponding to single photons is negligibly weak. Here we demonstrate a medium that is nonlinear at the level of individual quanta, exhibiting strong absorption of photon pairs while remaining transparent to single photons. The quantum nonlinearity is obtained by coherently coupling slowly propagating photons to strongly interacting atomic Rydberg states in a cold, dense atomic gas. Our approach paves the way for quantum-by-quantum control of light fields, including single-photon switching, all-optical deterministic quantum logic and the realization of strongly correlated many-body states of light.     

双光子J—C模型中非旋转波效应项对原子压缩效应影响的研究

应用数值计算方法计算双光子Ｊ－Ｃ模型中原子的压缩效应．在ＲＷＡ下原子具有较强的压缩效应．当虚光场介入时,弱耦合时还会出现相对较弱的压缩效应,强耦合时,压缩效应消失;而横向Ｓｔａｒｋ效应在弱耦合和强耦合时都使原子的压缩效应相对减弱．当两者皆存在时,即ＮＲＷＡ下原子的压缩效应减弱甚至消失．     

Au激光等离子体中Au48+的跃迁谱线和能级寿命的理论计算

根据扩展的相对论多组态Dirac-Fock理论,采用“全相对论原子结构程序（GRASP2）”,考虑重要核的有限体积效应、量子电动力学效应（QED）和Breit修正以及组态间的相互作用,计算类镓Au^48＋的能级寿命、能级宽度、跃迁波长、跃迁几率和振子强度。结果表明：计算所得的波长与最新的实验数据及其他参考数据较吻合;能级寿命与能级宽度的关系符合海森保的能量与时间测不准原理;在类镓Au^48＋的跃迁中,3d-4f是一条较强的通道。     

Kerr介质中非关联双模相干态场与V型三能级原子的相互作用原子布居概率的时间演化

导出了充满Ｋｅｒｒ介质的高Ｑ腔中非关联双模相干态场与Ｖ型三能原子相互作用系统的态矢量，通过数值计算，分析了Ｋｅｒｒ介质对原子能级布局概率的影响，绘出了原子布居概率的时间演化曲线，结果发现，原子布居概率受克尔效应的影响较大，随着克尔效应的增强在该曲线上附加一低频起伏．     

Electromagnetically induced transparency with resonant nuclei in a cavity

The manipulation of light-matter interactions by quantum control of atomic levels has had a profound impact on optical sciences. Such manipulation has many applications, including nonlinear optics at the few-photon level, slow light, lasing without inversion and optical quantum information processing. The critical underlying technique is electromagnetically induced transparency, in which quantum interference between transitions in multilevel atoms renders an opaque medium transparent near an atomic resonance. With the advent of high-brilliance, accelerator-driven light sources such as storage rings or X-ray lasers, it has become attractive to extend the techniques of optical quantum control to the X-ray regime. Here we demonstrate electromagnetically induced transparency in the regime of hard X-rays, using the 14.4-kiloelectronvolt nuclear resonance of the M?ssbauer isotope iron-57 (a two-level system). We exploit cooperative emission from ensembles of the nuclei, which are embedded in a low-finesse cavity and excited by synchrotron radiation. The spatial modulation of the photonic density of states in a cavity mode leads to the coexistence of superradiant and subradiant states of nuclei, respectively located at an antinode and a node of the cavity field. This scheme causes the nuclei to behave as effective three-level systems, with two degenerate levels in the excited state (one of which can be considered metastable). The radiative coupling of the nuclear ensembles by the cavity field establishes the atomic coherence necessary for the cancellation of resonant absorption. Because this technique does not require atomic systems with a metastable level, electromagnetically induced transparency and its applications can be transferred to the regime of nuclear resonances, establishing the field of nuclear quantum optics.