Quantum Statistical Properties of Binomial Field Interacting with Two Entangled Atoms

Quantum statistical properties of the binomial field interacting with the two entangled atoms are investigated for the different initial conditions. It is found that the sub-Poissonian distribution and the antibunching effect can be presented for the certain ranges of the involved parameters.     

Entropy of the Binomial Field Interacting with the Two Entangled Atoms

In this paper, we investigate entropy properties of the single-mode binomial field interacting with the two entangled two-level atoms. It is found that the different initial conditions lead to the different evolutions of entropy of the binomial field.     

Entropy of Field Interacting With Two Atoms in Bell State

In this paper, we investigate entropy properties of the single-mode coherent optical field interacting with the two two-level atoms initially in one of the four Bell states. It is found that the different initial states of the two atoms lead to different evolutions of field entropy and the intensity of the field plays an important role for the evolution properties of field entropy.     

Entanglement and Other Nonclassical Properties of Two Two-Level Atoms Interacting with a Two-Mode Binomial Field: Constant and Intensity-Dependent Coupling Regimes

In this paper, we consider the interaction between two two-level atoms and a two-mode binomial field with a general intensity-dependent coupling regime. The outlined dynamical problem has explicit analytical solution, by which we can evaluate a few of its physical features of interest. To achieve the purpose of the paper, after choosing a particular nonlinearity function, we investigate the quantum statistics, atomic population inversion and at last the linear entropy of the atom-field system which is a good measure for the degree of entanglement. In detail, the effects of binomial field parameters, in addition to different initial atomic states on the temporal behavior of the mentioned quantities have been analyzed. The results show that, the values of binomial field parameters and the initial state of the two atoms influence on the nonclassical effects in the obtained states through which one can tune the nonclassicality criteria appropriately. Setting intensity-dependent coupling function equal to 1 reduces the results to the constant coupling case. By comparing the latter case with the nonlinear regime, we will observe that the nonlinearity disappears the pattern of collapse-revival phenomenon in the evolution of Mandel parameter and population inversion (which can be seen in the linear case with constant coupling), however, more typical collapse-revivals will be appeared for the cross-correlation function in the nonlinear case. Finally, in both linear and nonlinear regime, the entropy remains less than (but close to) 0.5. In other words the particular chosen nonlinearity does not critically affect on the entropy of the system.     

克尔介质中"耦合双原子-场"模型的光场压缩效应

利用全量子理论，研究克尔介质中耦合二能级双原子与场相互作用的压缩效应，着重讨论了克尔介质对光场压缩效应的影响，并揭示了初始场强及原子间耦合系数的变化与光场压缩效应的关系。     

Interaction of Negative Binomial States with Two-Level Atoms

We study the interaction of negative binomial states with two-level atoms. The dynamical evolutions of atomic population inversion, field entropy, Q function, and phase distribution are investigated in detail. The field becomes a superposition of negative binomial states at certain times, and this is confirmed further by its photon number distribution.     

双模相干态和压缩真空态光场-非等同两原子体系的腔场谱

研究了两个非等同二能级原子与双模腔场相互作用过程的腔场谱.导出了双模初始光场处于任意量子态时腔场谱的计算公式,给出了光场处于相干态和压缩真空态时的数值结果,讨论了相对耦合常数R=g2/g1和初始场强对腔场谱的影响.发现相干态光场的腔场谱在R很小时为双峰,在R接近于1时为3峰.压缩真空态的腔场谱在弱场条件下表现为复杂的多峰结构,在强场条件下则只有单一经典共振峰或裂距很小的双峰.     

两耦合原子与双模二项式光场相互作用系统的腔场谱

研究了高Q腔中具有偶极相互作用的两个等同二能级原子与双模二项式光场相互作用过程的腔场谱,重点研究了两模腔场谱的干涉效应对谱结构的影响。结果表明:两模光场平均场强相等时,每模腔场谱一般出现对称多峰结构。随着初始场强的增加中间3峰趋于iω和ωi±0.7g处,而边峰消失。当两模初始场的频率差Δ大于6g(g为原子与腔场的耦合常量)时,两模间的干涉效应可以忽略;在Δ小于6g时,模间的干涉效应对腔场谱结构有明显的影响;尤其当Δ从1.4g逐渐减少时,模Ⅰ和模Ⅱ的三个主峰开始逐渐重叠,两模腔场谱之间出现了十分明显的干涉现象。     

与两等同Bell态纠缠原子相互作用光场的量子场熵

利用全量子理论,并通过数值计算,研究了初始处于Fock态的单模光场与两等同双能级纠缠原子单光子共振相互作用过程中单模光场量子场熵的时间演化特性.结果发现:当两原子初始处于第一种Bell态时,光场量子场熵的时间演化周期为π/g2(2n+1);随着初始光强的增大,光场与原子之间的量子纠缠现象减弱;特别是当时间t为演化周期的整数倍时,场－原子系统处于退纠缠状态.当两原子初始处于第二种Bell态时,光场量子场熵不随时间变化,恒为零.当两原子初始分别处于第三种和第四种Bell态时,光场量子场熵的时间演化曲线呈现不等幅周期振荡现象;并且随着初始光场光子数的增加,光场量子场熵的振荡周期逐渐增大,但振荡幅值逐渐减小.     

与量子光场相互作用的运动原子的熵压缩

运用量子信息熵理论,研究了与量子光场相互作用的二能级运动原子的熵压缩,讨论了原子运动和场模结构对原子熵压缩的影响,并且比较了分别从基于信息熵测不准关系和海森伯测不准关系出发得出的结果,表明原子的运动导致了原子熵压缩的周期性演化;随着场模结构参量的增大,熵压缩的演化周期缩短,压缩时间延长;选择适当的系统参量,运动原子能够呈现长时间的持续熵压缩效应。当原子反转为零时,基于海伯堡测不准关系的方差压缩定义不再有效,而熵压缩实现了对原子压缩效应的高灵敏量度。     

双模压缩真空场与二能级原子相互作用系统中光场的压缩特性

研究了双模压缩真空场与二能级原子双光子跃迁相互作用系统中光场的压缩特性及虚光了过程对光场压缩特性的影响。数值计算结果表明,光场呈现出周期性压缩现象,而虚光子过程则对光场的压缩有抑制作用并产生了量子噪声,光场的压缩与系统初始状态及本身性质密切相关。     

二项式光场与运动二能级原子相互作用系统的保真度

利用数值计算的方法研究了运动的二能级原子在二项式光场作用下系统的保真度随时间的演化,并讨论了不同的初始态对保真度的影响。结果表明,原子的运动速度仅仅影响保真度的振荡周期,而原子的不同初态及光场的参数对保真度的影响较大,当原子处于叠加态以及光场初始平均光子数较大的情况下系统的保真度较高。     

与运动原子相互作用的场的压缩效应

采用量子光学中时间演化算符方法，研究了与运动原子相互作用的场的压缩效应，揭示了光场的初始平均光子数和场模结构参数对光场压缩特性的影响，结果表明：适当选择系统参数，可获得在时间上持续压缩的压缩光。     

非等同两原子与光场相互作用系统的腔场谱

研究了两个二能级原子与单模腔场具有不同耦合常量系统的腔场谱,讨论了量子化光场分别处于不同的光子数态时腔场谱结构随相对耦合常量R变化的新特性。发现随着R由0到1的增加,腔场谱各对应峰峰位相对腔场原共振频率ω0对称偏移;真空场（n=0）的峰高在0〈R〈0．3内变化较快,其拉比峰个数按2→6→4规律变化;弱场（n=1）峰高在0〈R〈0．5内变化较快,其峰数量按2→6→12→9→7规律变化;强场（n=8）峰高在0〈R〈0．1内改变迅速,其峰数量按2→8→11→5规律变化,谱结构显得更加复杂;进一步的计算表明,当n〉〉8时。其峰的数量按3→5→3规律变化。同时发现,R=0和R=1时,峰的数量相对较少。各峰峰高之和由最小单调增至最大,这在物理上反映了原子的协作效应。     

Information Entropy Squeezing of a Two-Level Atom Interacting with Two-Mode Coherent Fields

From a quantum information point of view we investigate the entropy squeezing properties for a two-level atom interacting with the two-mode coherent fields via the two-photon transition. We discuss the influences of the initial state of the system on the atomic information entropy squeezing. Our results show that the squeezed component number, squeezed direction, and time of the information entropy squeezing can be controlled by choosing atomic distribution angle, the relative phase between the atom and the two-mode field, and the difference of the average photon number of the two field modes, respectively. Quantum information entropy is a remarkable precision measure for the atomic squeezing.     

Information Entropy Squeezing of a Two-Level Atom Interacting with Two-Mode Coherent Fields

From a quantum information point of view we investigate the entropy squeezing properties for a two-level atom interacting with the two-mode coherent fields via the two-photon transition. We discuss the influences of the initial state of the system on the atomic information entropy squeezing. Our results show that the squeezed component number,squeezed direction, and time of the information entropy squeezing can be controlled by choosing atomic distribution angle,the relative phase between the atom and the two-mode field, and the difference of the average photon number of the two field modes, respectively. Quantum information entropy is a remarkable precision measure for the atomic squeezing.     

Exactly Solvable Model of a Two-Level Quantum System Interacting with Spin Environment

An exactly solvable model of a two-level quantum system interacting with spin environment is considered. The interaction is assumed to be such that the state of the environment is conserved. Dynamics of the reduced density matrix of the two-level system is calculated for arbitrary coupling strength. The stationary state of the spin is obtained explicitly in the t limit.     

与非等同双原子相互作用下光场的量子特性

研究了具有不同偶极矩的两个原子与双模压缩真空场相互作用系统中光场的量子特性.讨论了两个原子与双模压缩真空场的相对耦合常数(R=g1/g2)和光场的初始压缩因子r对光场的压缩效应和光子的聚束与反聚束效应的影响.数值计算结果表明,光场量子涨落的震荡幅度、最大压缩深度、压缩时间及二阶相干度的震荡振幅与光场的初始压缩因子r的大小有关.两原子与双模光场的相对耦合常数R影响着光场量子涨落和二阶相干度的震荡规律,因而也影响着压缩时间、光场处于非经典态的时间及光子的反聚束程度,但对光场的压缩深度无明显影响.     

Quantum Correlation of Two Entangled Atoms Interacting with the Binomial Optical Field

Quantum correlations of two atoms in a system of two entangled atoms interacting with the binomial optical field are investigated. In eight different initial states of the two atoms, the influence of the strength of the dipole-dipole interaction, probabilities of a the Bernoulli trial and particle number of the binomial optical field on the temporal evolution of the geometrical quantum discord between two atoms are discussed. The result shows that two atoms always exist the correlation for different parameters. In addition, when and only when the two atoms are initially in the maximally entangled state, the temporal evolution of geometrical quantum discord is not affected by the parameters, and always keep in the degree of geometrical quantum discord that is a fixed value.     

Kerr介质中耦合V型三能级原子与相干态光场作用场的量子性质

研究了Kerr介质中相干态光场与耦合V型三能级原子相互作用过程中场的量子性质.利用量子光学中光场与原子相互作用的耦合Tavis-Cummings模型,对系统的动力学过程进行了求解.讨论了系统初始状态、失谐量、原子间偶极相互作用强度及Kerr系数对光场量子性质随时间演化的影响.数值计算结果表明:初态中场的平均光子数比较小时,光场能够展现出明显的量子效应|初始时刻原子激发态概率幅从小变大时,光场的反聚束效应变得越明显,而光场的压缩深度会先增大后减小|失谐量的变化对场的量子性质的影响不大,只是改变光场二阶相关函数和压缩参量振荡的周期|原子间耦合强度的增大使光场的反聚束效应减弱和光场的压缩深度变浅|Kerr系数的增大会增强光场的反聚束效应,而使光场的压缩深度变浅.