位相相干态的数相高阶压缩

本文根据Ｐｅｇｇ－Ｂａｒｎｅｔｔ的量了相位理论和Ｈｏｎｇ－Ｍａｎｄｅｌ的高阶压缩概念，研究了有限维空间谐振子位相相干态中粒子数和相位的高阶压缩效应，研究结果表明，在特定的条件下，位相相干态的粒子数和相位都可呈出最大程度的高阶压缩。     

奇偶相干态中测量相位算符的涨落及其压缩

利用Ｂａｒｎｅｔｔ和Ｐｅｇｇ提出的测量相位算符讨论了奇偶相干态中的相位涨落及其高阶涨落，在测不准关系和高阶测不准关系基础上给出了测量相位压缩和高阶压缩的二类定义，并用这二类定义研究了奇偶相干态中测量相位的二阶和高阶压缩情况。     

原子相干态中角动量的高阶涨落及高阶压缩

利用SU(2)李代数讨论了原子相干态中角动量的二阶、四阶和六阶涨落,并在高阶不确定关系基础上提出了角动量高阶压缩的定义.研究了原子相干态中角动量涨落的二阶、四阶和六阶压缩情况.运用这里的定义和方法可进一步研究更高阶的压缩情况,从而把高阶压缩推广到原子算符的涨落上. 关键词： 原子相干态 Bloch态 SU(2)压缩     

q变形叠加态及其特性

利用ｑ－振子代数提出了一种由ｑ变形振子的本征态（ｑ变形光子数态）叠回由成的态。给出了这种ｑ有叠加态的定义,研究了它们的量子统计性质。也讨论了这种态的压缩和ｑ压缩,并进一步研究了它们的寻常高阶压缩和ｑ高阶压缩。ｑ变形振子是一种非线性振子,通过这些讨论,推广通常的叠加态。     

热噪声的相干态和压缩态中的高阶涨落

利用热场动力学的方法研究了具有热噪声的相干态和压缩态中场正交分量的高阶涨落和高阶压缩.利用测量相位算符讨论了这些热化态中相位的高阶涨落.从而得到在有限温度下这些态的低阶及高阶涨落与温度的关系和压缩特性与温度的关系.由于实际的场态总是在一有限的温度下，所以讨论温度对涨落和压缩的影响是很有意义的. 关键词：     

压缩真空态的高阶非经典性质

通过高阶压缩效应,高阶反聚束效应和二阶亚泊松分布等统计性质,研究了压缩真空态的高阶非经典性质。采用数值计算方法,讨论了压缩参数对态的高阶非经典性质的影响。研究结果表明:压缩真空态呈现出高阶压缩效应和四阶反聚束效应,并且这些非经典性质均随压缩参数增大而增强。但它未呈现出一至三阶反聚束效应,也没有展示出一阶亚泊松分布和二阶亚泊松分布等特性。     

原子偶极矩的高阶压缩

由高阶测不准关系给出了物理量的高阶基本量子涨落,并由此定义了原子偶极矩的高阶压缩。以光场初态是迭加态的双光子J-C模型为例进行了讨论。 关键词：     

原子薛定谔猫态中角动量的压缩及其时间演化

在低Q值腔内，原子相干态在一些特定时刻可以演化为原子薛定谔猫态.讨论了在这种原子薛定谔猫态中原子角动量的涨落和高阶涨落.根据不确定性原理，进一步研究了原子角动量的压缩和高阶压缩性质及其演化.研究表明，原子薛定谔猫态可以被压缩到二阶和六阶，但不能被压缩到四阶.当原子薛定谔猫态中被叠加的原子相干态数为无限多项时，其压缩特性与原子相干态相同. 关键词： 原子相干态 薛定谔猫态 角动量压缩 Bloch态     

相干态的叠加态的量子统计性质

本文研究了相干态的叠加态的量子统计性质.结果表明,相干态的叠加态仅存在奇次幂的高阶压缩效应,而不存在偶次幂的高阶压缩效应.给出了高阶压缩和高阶反聚束效应与叠加系数间的函数关系.高阶压缩要求叠加系数的辐角取值满足cosθ>exp(-2|α|²),而高阶反聚束效应则要求0.5π<θ<1.5π.奇偶相干态的有关结果均作为特例应包含在本文的一般结论之中.     

奇偶q-变形相干态的高阶压缩效应

研究了奇偶q变形相干态中光场的高阶压缩效应.数值计算结果发现,奇偶q变形相干态中光场的高阶压缩效应与参数值q有关,当参数q取偏离1较大的值时,q变形奇偶相干态均可具有奇次方阶压缩效应却无偶次方阶压缩效应,这与通常奇偶相干态的压缩特性是不同的 关键词： 光场 q变形相干态 高阶压缩效应     

Study of higher order non-classical properties of squeezed Kerr state

Recently, Prakash and Mishra [J. Phys. B: at. Mol. Opt. Phys., 39, 2291(2006); 40, 2531(2007)] have studied higher order sub-Poissonian photon statistic conditions for non-classicality in the form of general inequalities for expectation values of products of arbitrary powers of photon number and of photon-number fluctuation. It is, therefore, vital to study the generation of these higher order sub-Poissonian photon statistics (phase-insensitive behavior) in a physically realizable medium and their relations to higher order squeezing (phase-sensitive behavior). In the present paper, we study higher order non-classical properties, such as Hong and Mandel squeezing, amplitude-squared squeezing and higher order sub-Poissonian photon statistics, of squeezed Kerr state which is generated by squeezing the output of a Kerr medium whose input is coherent light. Such states can be realized if laser light is sent through an optical fiber and then into a degenerate parametric amplifier. It is established that the squeezed Kerr state can exhibit higher order non-classical properties.     

High-order squeezing of pure superposition states

Ｈｉｇｈ－ｏｒｄｅｒｓｑｕｅｅｚｉｎｇｏｆｐｕｒｅｓｕｐｅｒｐｏｓｉｔｉｏｎｓｔａｔｅｓＭＡＡｉｑｕｎ（ＨａｒｂｉｎＣｏｌｌｅｇｅ，Ｈａｒｂｉｎ，１５００２０，Ｃｈｉｎａ）ＺＨＡＮＧＹａｎｘｕｎ（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓ，ＨａｒｂｉｎＮ...     

Superposed graphene coherent states

Using an annihilation operator, coherent states related to the electron of graphene layer placed in a magnetic field, can be obtained. In this paper, we define even and odd superposed graphene coherent states and then, we consider their entanglement, squeezing and statistical properties. To study the entanglement, we use concurrence. The results show that odd superposed graphene coherent states are maximally entangled states for all values of coherence parameter. However, the entanglement of graphene coherent states and also even superposed depend on the coherence parameter. In addition, examining the Mandel parameter shows sub-Poissonian statistics for graphene coherent states and their odd superposition; while, even superposed states do not show sub-Poissonian statistics at all. Also, we find that graphene coherent states and even superposition may be squeezed while the odd states do not show squeezing.     

f-Deformed Squeezed Vacuum and First Excited States,Their Superposition and Corresponding Nonclassical Properties

In this paper, we introduce two new classes of nonlinear squeezed states that we name as f-deformed squeezed vacuum state|ξ, f even and f-deformed squeezed first excited state |ξ, f odd, which according to their production processes, essentially include only even and odd bases of Fock space, respectively. In the continuation, we introduce the superposition of these two distinct nonlinear squeezed states with a respective phase ?. Then, some of the criteria which imply the nonclassicality of the states, such as Mandel parameter, second-order correlation function, quadrature squeezing, amplitude-squared squeezing, Husimi and Wigner–Weyl quasi-distribution functions, are numerically examined. At last, by considering a well-known nonlinearity function associated with a nonlinear physical system, we present our results which outcome from the numerical calculations. It is shown that, the introduced f-deformed states can reveal high nonclassical features.     

Experimental demonstration of a simple method to engineer a single qutrit state with biphotons

A simple method to engineer qutrit state with biphotons is realized. The method is based on Hong–Ou–Mandel interferometer and it is insensitive to disturbance comparing to Mach–Zehnder interferometer in principle. Moreover, a tomography procedure is employed to reconstruct the output states.     

Photon-Added SU(1, 1) Coherent States and their Non-Classical Properties

The photon-added coherent states of Barut-Girardello and Perelomov types are constructed using Holstein-Primakoff realization of the su(1, 1) Lie algebra. Basic properties of the constructed states have been discussed. In addition, their non-classical features have been analyzed by computing photon detection probability distribution, Mandel Q-parameter and quadrature squeezing. It is shown that SU(1, 1) photon-added coherent states may exhibit sub-Poissonian statistics and quadrature squeezing for a chosen set of parameters. Moreover, it has been observed that their non-classical behavior increases as the number of added-photons increases.

     

多模辐射场的广义非线性高阶差压缩——N次方X压缩的一般理论

本文在发展现有理论的基础上,提出了多模(2q模)辐射场的广义非线性高阶差压缩(即N次方X压缩)的定义,给出N次方X压缩效应的压缩度的计算公式,并对N-X最小测不准态和N-X压缩最小测不准态等进行了详细讨论.指出,MarkHilery在文献6中所提出的有关双模辐射场的“差压缩”的定义,仅仅是本文所提出的多模辐射场的广义非线性高阶差压缩(即N次方X压缩)的一般性定义在q=1、N=1条件下的特例.     

Observation of bunching of two bell states

The bunching of two single photons on a beam splitter is a fundamental quantum effect, first observed by Hong, Ou, and Mandel. It is a unique interference effect that relies only on the photons' indistinguishability and not on their relative phase. We generalize this effect by demonstrating the bunching of two Bell states, created in two passes of a nonlinear crystal, each composed of two photons. When the two Bell states are indistinguishable, phase-insensitive destructive interference prevents the outcome of fourfold coincidence between the four spatial-polarization modes. For certain combinations of the two Bell states, we demonstrate the opposite effect of antibunching. We relate this result to the number of distinguishable modes in parametric down-conversion.