单核子在具有八极形变的平均势场中的混沌运动(I)相干态在势场中传播的理论表示

单核子在具有八极以上形变的平均势场中发现有混沌运动．通过研究系统非定态波函数的时间演化特征,而使研究量子混沌与研究经典混沌的思路更趋一致,特别是能体现量子状态对初始条件的敏感性。给出了当初态选为二维不对称谐振子动力学对称条件下的、满足坐标动量最小测不准关系的相干态时,八极形变耦合作用下量子状态正则变量的期望值及测不准度随时间演化的理论表示．     

单粒子在非轴对称八极形变势场中的混沌运动

针对单粒子处在长椭球谐振子势加上Y₃₂+Y_3－2形变势场中的情况, 从经典和量子两个角度分析了粒子在非轴对称八极形变势场中的混沌运动. 通过经典的轨道稳定性分析, 指出了系统等势能面性质对粒子运动特点的重要性. 又通过对体系存在的能级免交叉现象, 三维不对称谐振子相干态在势场中的演化特征的研究, 具体地说明了八级形变势的非轴对称性使单粒子更容易出现混沌运动.     

经典粒子在轴对称八极形变势场中的混沌运动

在自然界中长的变形核数目多于扁的变形核数目, 这一事实发现与核子的混沌运动有关. 经典理论的初步研究表明, 粒子在扁椭球加八极形变场中比在长椭球加八极形变场中的运动能在更小的形变参数下产生混沌运动, 原因是前者的势能面能在更小的形变参数下出现负曲率.     

Chaotic Motion of a Nucleon in Heavy Nuclei with Necked-in Shape

In the framework of two-center shell model the nearest neighboring level spacing distribution and spectral rigidity of the nucleon in heavy nuclei are calculated when the shape parameters are changed systematically. Two regions of shape parameter in which the chaotic motion of the nucleon occurs are found. It is shown that the chaotic motion appears not only in the heavy nuclei with oblate shapes but also in prolate ones with a considerable neck, which is quite different from the conclusions of Ref. [2]. Bohigas Giannoni Schmit conjecture is corroborated once again by the good quantum-classical correspondence of nucleonic regular (chaotic) motion. In addition, the present work suggests that nuclear dissipation is shape-dependent,strong dissipation is expected for medium or larger separations, and provides nuclear dissipation with a dynamical understanding.     

SU(2)对称破缺下的氰化氘分子的混沌运动

用SU(2 )陪集表象来表示氰化氘分子 (DCN)两个耦合的伸缩振动模式 ,在混沌运动研究中 ,这是一个最简单的SU (2 )对称被破坏的模型。研究表明 ,当振动能量小于 1 2 5 0 2cm- 1 时 ,体系呈现规则运动 ;能量处于 1 2 5 0 2cm- 1 和 1 82 4 6cm- 1 之间 ,规则和混沌运动并存 ;能量高于 1 82 4 6cm- 1 时 ,体系呈现完全的混沌运动。同时 ,在庞加莱截面上观察到了周期 3轨道 ,由Sarkovskii定理 ,这意味着混沌的出现。另外还表明 ,D -C伸缩键的量子数激发决定体系的混沌运动     

Generalized Coherent States of a Particle in a Time-Dependent Linear Potential

We derive, with an invariant operator method and unitary transformation approach, that the Schr6dinger equation with a time-dependent linear potential possesses an infinite string of shape-preseving wave-packet states 1φ,λ （t） having classical motion. The qualitative properties of the invariant eigenvalue spectrum （discrete or continuous） are described separately for the different values of the frequency ω of a harmonic oscillator. It is also shown that, for a discrete eigenvalue spectrum, the states 1φ,λ （t） could be obtained from the coherent state 1φ,λ （t）.     

Q形变的非简谐振子广义相干态

利用变换算符导出了Q形变的非简谐振子代数,由此得到Q形变的非简谐振子广义相干态．这些状态具有过完备性,是Q形变的自然算符的极小测不准状态．在主压缩区间中偶相干态的相对压缩率随形变程度的增大而增大．     

The Multicomponent Coherent States of the Lie Algebra SO(4)

The multicomponent coherent states associated with the Lie algebra SO(4) are presented. An inhomogeneous differential realization of SO(4) in this multicomponent coherent state space is obtained.     

Physical Properties,Field Purity,and Quantum Phase for a Two-Level Atom in Photon-Added Coherent States for the Morse Potential

In this paper, we consider a two-level atom (TLA) interacting with a field mode, which is initially in the photon-added coherent state for the Morse potential (PACSMP). We investigate the dynamical behavior of quantum entropy, the geometric phase, and the Mandel parameter and discuss the statistical and nonclassical properties of the field with regards to its PACSMP through the evolution of the Mandel parameter. We examine the effects of the number of added photons, the initial-state setting, and the Morse-potential parameters. We establish the relationship between the field purity, nonclassical properties, and geometric phase of the system state during the time evolution. The results show that the numbers of added photons and CSMP strength have the potential to affect the time evolution of the field purity, the geometric phase, and the Mandel parameter. We explore some important physical phenomena such as sudden death and sudden birth of the nonlocal correlation between TLA and field systems.     

Levitation of Extended States in a Random Magnetic Field with a Finite Mean

We study the localization properties of electrons in a two-dimensional system in a random magnetic field B(r)=B₀+δB(r) with the average B₀ and the amplitude of the magnetic field fluctuations δB. The localization length of the system is calculated by using the finite-size scaling method combined with the transfer-matrix technique. In the case of weak δB, we find that the random magnetic field system is equivalent to the integer quantum Hall effect system, namely, the energy band splits into a series of disorder broadened Landau bands, at the centers of which states are extended with the localization length exponent ν=2.34±0.02. With increasing δB, the extended states float up in energy, which is similar to the levitation scenario proposed for the integer quantum Hall effect.     

Effective Two-Loop Thermodynamic Potential with Fermions in the Real-Time Formalism of Thermal Field Theory

Within the real-time formalism of thermal field theory, we apply the hard thermal loop resummation technique to calculate effective two-loop thermodynamic potential in quarkgluon and its renormalization. The result with collective effects is obtained, which is valid for an arbitrary number of quark flavors with masses.     

Study of Concurrence and D-Concurrence on Two-QubitsResulted in Pair Coherent States in Language of SU(2) Coherent States

Pair coherent state, is a state of a two-mode radiation field that is known as a state with non-gaussian wave function. In this paper, study on the pair coherent state, we notice that with superposition of two first terms of this states, one two-qubits formed. Because of the importance of two-qubits in theory of quantum entanglement, with two different measures with the title of concurrence and D-concurrence, we have studied the amount of entanglement and
discussed its details. At the end, we describe these measures for pair coherent states as a function of the amplitude of the SU(2) coherent states.     

减少光子奇(偶)对相干态的非经典特性

构造了减少光子奇对相干态与减少光子偶对相干态,并用数值模拟方法研究了它们的非经典特性。结果表明,从奇对相干态与偶对相干态的第一个场模取走光子,可以显著地增强第二个场模的光子统计亚泊松分布特性;从奇对相干态的第一个场模取走光子后,在双模光子消灭算符本征值的模较小时可以增强第一个场模的光子反聚束性质。从偶对相干态的第一个场模取走光子,在双模光子消灭算符本征值的模较小时第二个场模的光子反聚束效应得到明显增强。     

On the Mean Field Equations of Motion in the Theories with Unstable Vacuum

The problem of finding the mean field equations of motion in the theories with unstable vacuum is considered. The one- and two-loop quantum corrections to classical equations of motion are obtained. It is shown that these quantum corrections are real and causal.     

The Two-Variable Coherent States of the Quantum Algebra suq(l,1)

By means of the k-order q-boson realizations of su_q(1,1), a new kind of q-coherent states, the two-variable coherent states, are introduced for the quantum algebra su_q(l,1).They are relative to a definite irreducible representation of su_q(1,1) and shown to satisfy a completeness relation in a subspace of q-boson's Fock space. With the help of these coherent states the z-representation, representation in functional space, for su_q(1,1) is also discussed.     

Paul阱的含时广义SU(1,1)相干态

利用参量相关的Bogoliubov变换公式,导出描写Paul阱系统含时哈密顿的精确本征态--广义SU(1,1)相干态,讨论了关于这些态的粒子数涨落和平方振幅压缩特性.     

与核密度及温度相关的核子相对论微观光学势

在Walecka模型、热场动力学和相对论Dirac-Bruckner-Hartree-Fock计算结果基础上,研究了在不同核密度和各种温度情况下的核子相对论微观光学势及其相应的薛定谔等效势和平均自由程,计算结果表明,对于不同的温度,核子的薛定谔等效势与平均自由程随核密度变化较为敏感,而核温度对核子的薛定谔等效势和平均自由程的影响随着核密度的增加变大.     

与双原子相互作用的双模关联场的相位性质

根据Pegg和Barnett相位理论研究了与双原子相互作用的双模SU（1,1）相干场的相位特性,证明了光场每个模的相位及两个模的相位差均保持随机分布,给出了光场两个模的相位和方差的表达式,揭示了在适当的初始条件下,系统呈现原子的相干捕获现象。