叠加qs相干态的非经典性质

构造了叠加qs相干态,并研究了它的压缩性质、反聚束效应等非经典性质.数值计算了叠加系数和形变参数q与s对非经典性质的影响.奇偶qs相干态的有关结果作为特例包含在本文的一般结论之中.     

光的两种模式间的一种非经典性质的转移

利用与不变量有关的幺正变换方法并利用数值计算，研究了光的两种模式间的一种非经典性质的转移问题：Fock态(为非经典态)与相干态的相互转换问题. 关键词：     

奇偶对相干态的维格纳函数和层析图函数

利用纠缠态η〉表象下的维格纳算符,重构了奇偶对相干态的维格纳函数.根据维格纳函数在相空间中随变量ρ和γ的变化规律,讨论了奇偶对相干态的非经典性质和量子干涉效应.研究发现,奇偶对相干态总呈现非经典性质,并且当q取奇数时,奇偶对相干态更容易出现非经典性质.奇偶对相干态的量子干涉效应的显著程度与q取值有关,但对于q的同一取值,奇对相干态的量子干涉效应更为显著.利用纠缠态η〉表象下的维格纳算符Δ1,2(ρ,γ)和纠缠态η,τ1,τ2〉的投影算符之间满足的拉东变换,获得了奇偶对相干态的量子层析图函数.     

双模场真空态与相干态的叠加态的准几率分布函数

辐射场的非经典态在量子光学中占有十分重要的位置,在实践中有着非常广泛的应用背景,因此如何构造出各种各样的非经典态引起了越来越多的人的极大兴趣和重视。本文中,我们构造了辐射场的一类新的非经典态,称之为双模真空态与相干态的叠加态。我们对该态做了详细的数值计算以及量子统计性质的讨论。我们构造了双模真空态与相干态的叠加态的数学结构,讨论了它的准几率分布函数。数值计算结果表明,双模真空态与相干态的叠加态具有非常显著的非经典性质,因此双模真空态与相干态的叠加态是一类新的非经典光场态。     

非简谐振子广义相干态的叠加态

研究了非简谐振子广义相干态的叠加态的非经典性质，得到了出现周期性压缩现象的充要条件并给出了反聚束效应与叠加系数之间的关系． 关键词：     

增、减光子奇偶相干态的Wigner函数

利用Fock态表象下的Wigner函数定义，重构了增、减光子奇偶相干态的Wigner函数，并据此 讨论了它们的非经典性质.结果表明：增光子奇偶相干态总呈现出非经典特征，而减光子奇 偶相干态分别仅在k为偶数和奇数时呈现出非经典特征. 关键词： 奇偶相干态 玻色算符的逆算符 Wigner函数     

增光子奇偶相干态的Wigner函数

利用相干态表象下的Wigner算符, 重构了增光子奇偶相干态的Wigner函数.根据此Wigner函数在相空间中随复变量α的变化关系, 讨论了增光子奇偶相干态的非经典性质. 结果表明, 增光子奇偶相干态总可呈现非经典性质, 且在m取奇(或偶)数时, 增光子偶(或奇)相干态更容易出现非经典性质. 根据增光子奇偶相干态的Wigner函数的边缘分布, 阐明了此Wigner函数的物理意义. 同时, 利用中介表象理论获得了增光子奇偶相干态的量子tomogram函数. 关键词： 增光子奇偶相干态 Wigner函数 中介表象 tomogram函数     

Λ型三能级原子与对相干态光场共振作用中的非经典性质

研究了对相干态光场与一个Λ型三能级原子的共振相互作用中的各种非经典性质,例如光场的反群聚效应,Cauchy-Schwart不等式违背,光场的双模压缩性质等,并发现这些非经典性质在对原子态进行测量后将得到增强.     

依赖强度耦合的级联三能级原子系统中双模压缩真空初态场的非经典性质

运用全量子理论研究了依赖强度耦合的级联三能级原子系统中双模压缩真空初态场的压缩及量子统计性质,并讨论了初始光场的压缩参量以及原子—光场单光子失谐量对光场非经典性质的影响.     

双模SU(2)相干态场与两个耦合原子相互作用的动力学

研究了SU(2)相干态场与两个原子非简并双光子相互作用系统中原子的动力学行为 和双模场的非经典性质,并讨论了双模场的总光子数,配分参量以及原子间偶极相互作用对 它们的影响. 关键词：     

Comparison between photon annihilation-then-creation and photon creation-then-annihilation thermal states:Non-classical and non-Gaussian properties

We investigate the nonclassical properties of arbitrary number photon annihilation-then-creation operation(AC) and creation-then-annihilation operation(CA) to the thermal state(TS), whose normalization factors are related to the polylogarithm function. Then we compare their quantum characters, such as photon number distribution, average photon number,Mandel Q-parameter, purity and the Wigner function. Because of the noncommutativity between the annihilation operator and the creation operator, the ACTS and the CATS have different nonclassical properties. It is found that nonclassical properties are exhibited more strongly after AC than after CA. In addition we also examine their non-Gaussianity. The result shows that the ACTS can present a slightly bigger non-Gaussianity than the CATS.     

Nonclassicality Generated by Applying Hermite–Polynomials Photon-Added Operator on the Even/Odd Coherent States

We examine nonclassical properties of the quantum state generated by applying Hermite polynomials photon-added operator on the even/odd coherent state (HPECS/HPOCS). Explicit expressions for its nonclassical properties, such as quantum statistical properties and squeezing phenomenon, are obtained. It is interesting to find that the HPECS/HPOCS exhibits sub-Poissonian distribution, anti-bunching effects and negative values of the Wigner function. Thus, we confirm the HPPECS/HPPOCS is a new nonclassical state. Finally, we reveal that the HPPECS/HPPOCS is a novel intelligent state by its squeezing effects in position distribution and quadrature squeezing.     

Supercurrent and Its Quantum Statistical Properkies in Mesoscopic Josephson Junction in the Presence of Nonclassical Light Fields

In this paper, we study the supercurrent in a mesoscopic Josephson junction (MJJ) and its quantum statistical properties in the presence of nonclassical light fields. We investigate in detail the influence of external nonclassical light fields on current-voltage step structures of the MJJ. We also study in detail quantum statistical properties of the supercurrent when the external quantum electromagnetic fields are even and odd coherent-sta!e light fields. It is shown that the supercurrent in the MJJ exhibits both squeezing effect and quantum coherence. It is demonstrated that the MJJ can feel the difference not only between classical light fields and nonclassical light fields but also between different nonclassical light fields.     

Higher-order nonclassical effects generated by multiple-photon annihilation-then-creation and creation-then-annihilation coherent states

We explore two observable nonclassical properties of quantum states generated by repeatedly operating annihilationthen-creation(AC) and creation-then-annihilation(CA) on the coherent state, respectively, such as higher-order subPoissonian statistics and higher-order squeezing-enhanced effect. The corresponding analytical expressions are derived in detail depending on m. By numerically comparing those quantum properties, it is found that these states above have very different nonclassical properties and nonclassicality is exhibited more strongly after AC operation than after CA operation.     

纠缠相干态的压缩特性

研究纠缠相干态的量子纠缠特性和压缩特性。计算和分析了纠缠相干态的纠缠度和单模、双模压缩特性。讨论了纠缠和压缩二种非经典效应的关系，发现可以通过操纵纠缠度来达到增加或减弱压缩的目的。并指出了单模压缩和双模压缩表现出完全不同的特性。     

利用分束器通过条件测量制备非经典光场态和量子纠缠态

把相干态和单粒子数态作为分束器的输入态，通过条件测量可以剪去输入相干态中的任意粒子数态，并研究了这些被剪切了的光场态的性质。结果显示剪去真空态和单粒子数态的输出态具有较强的压缩和亚泊松分布等非经典效应。把剪切了的输出态和真空态输入分束器，得到的输出态具有量子纠缠性质，从而制备出量子纠缠态，同时也验证了被剪切的输出态的非经典性。     

Superposition of Generalized q-Coherent States of the Non-harmonicOscillator and Their Nonclassical Properties

The superposition states, which are composed of the generalized q-coherent states of the non-harmonic oscillator, are presented. The quantum statistical properties of these states are studied. Then the influence of the superposition phase δ and the deformation parameter q on these nonclassical properties are discussed. It is shown that the superposition states exhibit higher-order (order of odd number) squeezing effect and antibunching effect respectively. When the superposition phase δ is taken values approach to 0 or π/2, these results approach the properties of the even or odd generalized q-coherent states of the non-harmonic oscillator. Especially, the effects are influenced by the parameter q. When the values of q is taken departure from 1 greatly, the nonclassical properties are more evidently.     

Higher-Order Nonclassicality in Photon Added and Subtracted Qudit States

Higher-order nonclassical properties of r photon added and t photon subtracted qudit states (referred to as rPAQS and tPSQS, respectively) are investigated here to answer: How addition and subtraction of photon can be used to engineer higher-order nonclassical properties of qudit states? To obtain the answer, higher-order moment of relevant bosonic field operators is first obtained and subsequently used to study the higher-order nonclassical properties (e.g., higher-order antibunching, higher-order squeezing, and higher-order sub-Poissonian photon statistics) of the corresponding states. These witnesses establish that rPAQS and tPSQS are highly nonclassical. To quantitatively establish this observation and to make a comparison between rPAQS and tPSQS, volumes of the negative part of Wigner function are computed. Finally, for the sake of verifiability of the obtained results, optical tomograms are also reported. Throughout the study, a particular type of qudit state named as a new generalized binomial state is used as an example.     

Quantum phase distribution and the number—phase Wigner function of the generalized squeezed vacuum states associated with solvable quantum systems

The quantum phase properties of the generalized squeezed vacuum states associated with solvable quantum systems are studied by using the Pegg-Barnett formalism.Then,two nonclassical features,i.e.,squeezing in the number and phase operators,as well as the number-phase Wigner function of the generalized squeezed states are investigated.Due to some actual physical situations,the present approach is applied to two classes of generalized squeezed states:solvable quantum systems with discrete spectra and nonlinear squeezed states with particular nonlinear functions.Finally,the time evolution of the nonclassical properties of the considered systems has been numerically investigated.