Continuous-variable quantum teleportation of even and odd coherent states through varied gain channels

This paper has investigated quantum teleportation of even and odd coherent states in terms of the EPR entanglement states for continuous variables. It discusses the relationship between the fidelity and the entanglement of EPR states, which is characterized by the degree of squeezing and the gain of classical channels. It shows that the quality of teleporting quantum states also depends on the characteristics of the states themselves. The properties of teleporting even and odd coherent states at different intensities are investigated. The difference of teleporting two such kinds of quantum states are analysed based on the quantum distance function.

Wigner functions and tomograms of the photon-depleted even and odd coherent states

Using the coherent state representation of Wigner operator and the technique of integration within an ordered product （IWOP） of operators, this paper derives the Wigner functions for the photon-depleted even and odd coherent states （PDEOCSs）. Moreover, in terms of the Wigner functions with respect to the complex parameter a the nonclassical properties of the PDEOCSs are discussed. The results show that the nonclassicality for the state ｜β, m〉o （or ｜β,m〉e） is more pronounced when m is even （or odd）. According to the marginal distributions of the Wigner functions, the physical meaning of the Wigner functions is given. Further, the tomograms of the PDEOCSs are calculated with the aid of newly introduced intermediate coordinate-momentum representation in quantum optics.

Even and Odd Coherent States for Time-Dependent Harmonic Oscillator

The dynamical invariant for a general time-dependent harmonic oscillator is constructed by making use of two linearly independent solutions to the classical equation of motion. In terms of this dynamical invariant we define the time-dependent creation and annihilation operators and relevantly introduce even and odd coherent states for time dependent harmonic oscillator. The mathematical and quantum statistical properties of these states are discussed in detail. The harmonic oscillator with periodically varying frequency is treated as a demonstration of our general approach.

Quantum Properties of Two-Mode Squeezed Even and Odd Coherent States

Two new types of quantum states are constructed by applying the operator s（ξ） = exp（ξ＊ ab - ξa＋b＋） on the two-mode even and odd coherent states. The mathematical and quantum statistical properties of such states are investigated. Various nonclassical features of these states, such as squeezing properties, the inter-mode photon bunching, and the violation of Cauchy-Schwarz inequality, are discussed. The Wigner function in these states are studied in detail.

Preparing quantum vortex states with odd Schrdinger cat states through a coupled waveguide system

A scheme is proposed for preparing a quantum vortex state with a coupled waveguide, in which a single-mode odd cat state with weak intensity and a single-mode coherent state are inserted in the input ports, respectively. The analytical wavefunction of the resulting state in the quadrature space is derived, and the vortex structure of the output state is analyzed. It is found that the obtained states, which may carry a vortex with topological charge index one, are entangled and nonclassical, depending only on the scaled propagation time and the weak intensity of the input odd cat state instead of the displacement parameter of the input coherent state. The phase distribution, however, in the quadrature space, depends on the displacement parameter of the input coherent state

Quasiprobability distributions of new kinds of even and odd nonlinear coherent states

Using a numerical computational method, quasiprobability distributions of new kinds of even and odd nonlinear coherent states （EONLCS） are investigated. The results show that the distributions of the new even nonlinear coherent states （NLCS） are distinct from those of the new odd NLCS and imply that the new EONLCS always exhibit some different nonclassical effects. Finally, with the aid of newly introduced intermediate coordinate-momentum representation in quantum optics, the tomograms of the new EONLCS are calculated. This is a new way of obtaining the tomogram function.

Amplitude-squared squeezing of the generalized odd-even coherent states of the anharmonic oscillator in a finite-dimensional Hilbert space

This paper discusses the properties of amplitude-squared squeezing of the generalized odd-even coherent states of anharmonic oscillator in finite-dimensional Hilbert space. It demonstrates that the generalized odd coherent states do exhibit strong amplitude-squared squeezing effects in comparison with the generalized even coherent states.

Phase properties of odd and even circular states

Phase properties of the even and odd circular states are studied within the Hermitian phase formalism of Pegg and Barnett. Exact analytical formulas for the distribution function and the variance of the phase operator are obtained and used to examine whether or not the even and odd circular states exhibit photon-number squeezing and phase squeezing.

Wigner functions and tomograms of the even and odd binomial states

Using the coherent state representation of Wigner operator and the technique of integration within an ordered product （IWOP） of operators, the Wigner functions of the even and odd binomial states （EOBSs） are obtained. The physical meaning of the Wigner functions for the EOBSs is given by means of their marginal distributions. Moreover, the tomograms of the EOBSs are calculated by virtue of intermediate coordinate-momentum representation in quantum optics.

Finite-dimensional even and odd nonlinear pair coherent states and their some nonclassical properties

In this paper a new class of finite-dimensional even and odd nonlinear pair coherent states （EONLPCSs）, which can be realized via operating the superposed evolution operators D±（τ） on the state ｜q, 0）, is constructed, then their orthonormalized property, completeness relations and some nonclassical properties are discussed. It is shown that the finite-dimensional EONLPCSs possess normalization and completeness relations. Moreover, the finite-dimensional EONLPCSs exhibit remarkably different sub-Poissonian distributions and phase probability distributions for different values of parameters q, η and ξ.

Properties of Phase and Their Evolutions in Damped Odd and Even Coherent States

The properties of measured phase operators in damped odd and even coherent states have been studied. The fluctuations associated with measured phase and their squeezing in these states are investigated. The phase properties in damped superposition coherent states are considered too with the help of measured phase operators. These fluctuations and their squeezing are affected by damping and evolve with time elapsing.

Studies on odd-parity states of the Sm atom

Two-step excitation and ionization processes are used to detect Sm atoms in many excited states populated with tunable lasers. The wavelength of the first laser is tuned to the resonances from the Sm 4f^6 6s^2 ^7FJ （J=0 6） states to many odd-parity states with different electronic configurations, where the atoms are detected by photoionization process using an ultraviolet laser with a wavelength of 355 nm. Precise measurements on the energy level and intensity for many Sm 4f^6 6s6p and 4f^5 5d6s^2 states have been carried out. In a theoretical analysis on the spectral data, such as peak position, relative intensity, many transitions can be identified as the resonances from the Sm 4f^6 6s^2 7FJ （J=0-6） states to the atomic states with 4f^6 6s6p and 4f^5 5d6s^2 electronic configurations. This work also reports many spectral data on the odd-parity states that cannot be found in the literature.

Superposition Coherent States and Their Properties

Special kinds of generalized superposition states, superposition coherent states, are studied in this paper. These states can be produced by superposing a pair of coherent states ｜ α 〉 and ｜- α 〉. Their quantum statistical properties, the fluctuations of field and squeezing have been discussed in detail. These properties are dependent on superposition phase. We also describe the squeezing regions in phase space for these states.

奇偶相干态信号场下的量子关联和纠缠

为了实现两原子之间的非经典关联,借助于电磁诱导光透明(electromagnetically induced optical transparency,EIT)机制,利用量子态的映射技术,研究原子系综内两原子的量子关联和纠缠。结果表明:分别通过测量扰动刻画的量子关联和并发度刻画的量子纠缠,发现它们都能够被绝热地生成,但是,随着平均光子数的增加,二者的演变完全不同。随着平均光子数的增加,无论信号场是奇数相干态还是偶数相干态,它们都有利于量子关联的生成。对于奇相干态信号场,量子纠缠随着光子数的增加而逐渐减小;对于偶相干态信号场,量子纠缠却经历了一个先增加后减小的过程。系综内原子个数的增加,使得原子间的退相干加剧,从而导致量子关联和纠缠都被削弱。

kth-order antibunching effect for a new kind of excited even and odd q-coherent states

A new kind of excited even q-coherent states （aq^-1）^m｜α〉q^e and excited odd q-coherent states （aq^-1）^m｜α〉q^o is constructed by acting with inverse boson operators on the even and odd q-coherent states. The m dependence of the kth-order antibunching effect is numerically studied for k = 2, 3, 4, 5. It is shown that the kth-order antibunching effect enhances as m increases. The larger k, the quicker the antibunching effect enhances.

Difference in Number of Electrons in Inner Shells of Charged or Uncharged Elements in Organic and Inorganic Chemistry: Compatibility with the Even-Odd Rule

The recently introduced even-odd rule has been shown to successfully represent chemical structures of ions and molecules. While comparing available drawings in the scientific literature with the list of compounds predicted by the even-odd rule, it became however obvious that existing compounds are fewer than expected. Several predicted compounds involving many covalent bonds have apparently never been experimentally observed. Neutral oxygen for instance is expected to have 6 valence electrons, whereas oxygen can only build a maximum of two bonds, as in water. This specificity is observed for elements in the top-right corner of the periodic table. For compounds to contain only single covalent bonds, and thus follow the even-odd rule, further explanations are necessary. The present paper proposes that those specific elements experience a transfer of electrons from the valence shell into the inner shell, making them unavailable for further bonding. These elements will be described as organic, hereby providing a clear and hopefully unifying definition of the term. In opposition, inorganic elements have a constant inner shell no matter their electrical state or the number of bonds they maintain. More than 70 compounds involving 11 elements of the main group are studied, revealing a progression from fully inorganic elements at the left of the periodic table to fully organic elements. The transition between inorganic or organic elements is made of few elements that take an organic form when negatively charged;they are labelled semi-organic. The article concludes that the fully organic elements of the main group are Oxygen and Fluorine, whereas semi-organic elements are more numerous: C, N, S, Cl, Se, Br and I. Thus, the even-odd rule becomes fully compatible with scientific knowledge of compounds in liquid or gaseous phase.

基于奇/偶互补磁场理论的自起动永磁同步电机两种运行状态研究

基于奇/偶互补磁场理论的新型自起动永磁同步电机(line-start permanent magnet synchronous motor,LSPMSM)根据定子绕组两种联结方式,可分为不同的运行状态。定子仅主绕组接入电网时,电机处于“互补磁场”状态,此时转子同位线圈电阻的折算值增大,电抗折算值不变,进而在起动初期缩小电机冲击电流的同时,增大起动转矩。定子主绕组与次绕组同时供电时,电机处于常规状态,此时定子绕组电磁性能等效于正规60°相带设计,稳态运行时性能与普通LSPMSM相同。该文分别对新型电机两种运行状态下的工作原理、等效电路和转矩–转速曲线进行分析。建立有限元仿真模型,对样机两种运行状态的堵转性能、起动性能进行研究,并分别研究样机在空载、重载起动条件下的切换过程。样机试验与仿真结果表明,轻载时在牵入同步速度附近切换运行状态,重载时在0.6倍额定转速前切换运行状态,新型电机能够兼顾高起动性能与高稳态性能。

基于决策树方法的奇A核基态自旋预测

作为原子核的基本性质,基态自旋一直是原子核数据与核结构基础研究领域的热点.本文采用决策树方法对核素图上的奇质量数原子核(奇A核),包括奇质子数原子核(奇Z核)与奇中子数原子核(奇N核),进行了深入的研究,并分别训练了奇Z核与奇N核的基态自旋预测模型.其中在以75%∶25%的比例随机划分训练集与验证集的情况下,奇Z核的训练集和验证集的正确率分别达到98.9%和79.3%;奇N核的训练集和验证集的正确率分别达到98.6%和71.6%.同时,通过1000次随机选择训练集和验证集进行重复验证,得到的正确率的标准误差均小于5%,进一步验证了决策树的可靠性和泛化性能;另一方面,决策树的正确率远高于核结构研究中常用的理论模型,如Skyrme-Hartree-Fock-Bogoliubov (SHFB)理论、协变密度泛函理论(CDFT)、有限程液滴模型等.接下来,以所有自旋确定的奇Z核和奇N核为学习集,对共计254和268个自旋未确定但有推荐值的奇Z核和奇N核的基态自旋值进行了预测,预测集符合率分别达到68.5%和69.0%.最后,选择Z=59,Z=77,N=41以及N=59四条奇质量数链,讨论了决策树的学习(预测)结果与相应原子核的实验(推荐)值,以及3种理论模型所给出结果的异同,进一步展示了决策树在原子核基态自旋方面的研究与应用价值.

Dynamics of Nonclassicality of Time-and Conductivity-Dependent Squeezed States and Excited Even/Odd Coherent States

Recently, the quantum description of electromagnetic waves in conducting media has been performed. It has been demonstrated that in particular case, the Hamiltonian of the corresponding field can be expressed by Caldirola–Kanai Hamiltonian. In this paper, using the associated annihilation and creation operators of the above-mentioned quantized field, the time-and conductivity-dependent squeezed vacuum and one-photon squeezed states as well as their superpositions, and also the time-and conductivity-dependent excited even and odd coherent states are produced. Also,using a few well-known nonclassicality criteria, the time evolution of nonclassicality features of the above classes of obtained states, in addition to the influence of medium conductivity on them are demonstrated, numerically. It has been shown that the nonclassicality indicators may be adjusted by tuning the conductivity of media.

多模奇相干态光场中的N-Y最小测不准态与N-H最小测不准态

本文根据新近建立的多模辐射场的广义非线性等阶高阶压缩理论，对多模奇相干态光场｜Ψ，ｏ〉ｑ中的Ｎ次方Ｙ压缩、Ｎ次方Ｈ压缩、Ｎ－Ｙ最小测不准态以及Ｎ－Ｈ最小测不准态等进行了详细研究．结果表明：１）当压缩阶数Ｎ为偶数时，多模奇相干态｜Ψ，ｏ〉ｑ总是恒处于Ｎ－Ｙ最小测不准态；当Ｎ为奇数时，态｜Ψ，ｏ〉ｑ既不处于Ｎ－Ｙ最小测不准态，也不呈现Ｎ次方Ｙ压缩效应．２）当ｑ·Ｎ为偶数时，多模奇相干态｜Ψ，ｏ〉ｑ总是恒处于Ｎ－Ｈ最小测不准态；当ｑ·Ｎ为奇数时，态｜Ψ，ｏ〉ｑ既不处于Ｎ－Ｈ最小测不准态，也不呈现Ｎ次方Ｈ压缩效应．３）多模奇相干态｜Ψ，ｏ〉ｑ恒处于Ｎ－Ｙ最小测不准态与恒处于Ｎ－Ｈ最小测不准态的条件明显不同。