1990年, 第13卷, 第3期　
刊出日期：1990-04-30

  

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  Global Convergence of Chaotic Orbit Computations for Non-Integrable Dissipative Systems

  WANG Bing-hong

  理论物理通讯. 1990, 13(3): 271-276.

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  The computational convergence problem of chaotic orbits is discussed for nonintegrable dissipative dynamical systems. It is demonstrated that although the detailed convergence has been lost, the asymptotic global behaviors generated by chaotic orbits are numerically convergent if computational round-off and truncation errors are decreased.
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  The Improved Subregular Model and the Phase Diagram of a Binary System

  CHEN Li-rong

  理论物理通讯. 1990, 13(3): 277-286.

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  In thia paper an improved subregular model is proposed. Using the thermodynamic theory the equations describing liquid-solid phase equilibrium curve are obtained. For some typical phase diagrams of a binary system we give their predictive criteria of the phase diagram type. We enumerate 4 binary alkali halide systems, their phase diagrams are calculated respectively, this improved model is tested. The results calculated show that the agreement between the theoretical phase diagram and its corresponding experimental points is good.
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  Green's Functions in Coupled-Cluster Form

  HU Cheng-zheng

  理论物理通讯. 1990, 13(3): 287-298.

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  The Green's function and coupled-cluster (CC) methods are two important tools of quantum many-body theory. It seems worthwhile to find their connection. In the present paper we demonstrate this connection and give the expressions of the Green's functions in the CC form. Diagrammatic techniques are used to write explicit algebraic expressions.
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  Asymptotic Behaviors of Multi-Soliton Solutions of the Cubic and the Modified Nonlinear Schrodinger Equation

  Zong-yun CHEN

  理论物理通讯. 1990, 13(3): 299-306.

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  From the determinant expressions of multi-soliton solutions of the cubic and the modified nonlinear Schrodinger equation which are obtained from the reduced Zakharov-Shabat equations, asymptotic behaviors of them in the case of t→±∞ are directly derived.
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  Balance Equations for Quantum Tunneling

  J. CAI, X.L. LEI

  理论物理通讯. 1990, 13(3): 307-316.

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  We have established a set of balance equations to demonstrate the hot electron effect in the quantum tunneling processes by using the well-known effective tunneling Hamiltonian model. The high field effects both in reservoirs and in barrier region are discussed in detail. We also find a new field-dependent characteristic time due to nonequilibrium of reservoirs (the left-and right-sides of the barrier region) in the double-barrier structure.
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  Statistical Fluctuation of Linear-System Driven by Colored Noise

  BA0 Jing-dong, ZHUO Yi-zhong, ZHANG Jing-shang

  理论物理通讯. 1990, 13(3): 317-326.

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  The Brownian motion driven by colored noise in the harmonic oscillator potential is studied, and the "best Fokker-Planck equationn" is proposed. The analytical formulse of the second moments of coordinate and velocity are obtained. The fluctuation behavior of a system under influence of the correlation time of colored noise is discussed.
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  Second Order Correction of Relativistic Optical Potential

  MA Zhong-yu, SUN Zi-yang, ZHUO Yi-zhong, GENG Tian-ming, ZHENG Chang-ying

  理论物理通讯. 1990, 13(3): 327-340.

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  The imaginary part of the off-energy shell optical potential of a nucleon in nuclear matter, where the polarization and correlation contribution of the exchanges of the σ and ω mesons are taken into account, is derived in the framework of the relativistic meson-nucleon field theory. The second order correction of the real part of the optical potential is calculated in terms of the dispersion relation and the effective mass of a nucleon in the nuclear medium is also investigated in this paper.
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  Clebsch-Gordan Coefficients, Racah Coefficients and Braiding Fusion of Quantum sl(2) Enveloping Algebra Ⅱ

  Bo-yu HOU, Bo-yuan HOU, Zhong-qi MA

  理论物理通讯. 1990, 13(3): 341-354.

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  The explicit forms of the quantum Clebsch-Gordan coefficients and the first-type quantum Racah coefficients for the quantum sl(2) enveloping algebra are computed in detail. Exact values of some coefficients are listed. An important relation, quantum Racah sum rule, is proved.
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  Some Possible Effects of the Absorptive Part of Penguin Diagram

  Dan-di WU, Xue-qian LI, Ping WANG

  理论物理通讯. 1990, 13(3): 355-364.

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  The absorptive part of the penguin diagram (APP) is one of the necessary conditions for some CP violation quantities. In this paper, we investigate some possible effects of APP in D^o and B^o systems including isospin asymmetry in the final states and phase shift in parameters, and decay rate difference of D^o and D^o, even though it is hard to observe them in near future and in contrast, this effect does not appear in K-system.
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  Pseudo-Scalar Meson Wavefunctions and Exclusive Decays of D and B Mesons

  Xin-heng GUO, Tao HUANG

  理论物理通讯. 1990, 13(3): 365-382.

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  Pseudo-scalar meson wavefunctions are proposed. Their moments are consistent with the QCD sum rule and lattice gauge results. The radii and transverse momenta of these wavefunctions are discussed. We develop a method and apply these wavefunctions to calculate the exclusive semileptonic and nonleptonic decays of D-and B-mesons. The results are in good agreement with experiments. We find an upper limit on |V_ub| as 0.01. We also find that the parameter ξ may not be zero in nonleptonic decays of D-and B-mesons.
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  Three-Loop Calculations and Low-Energy Effective Action in the Non-Linear Sigma Model

  Lin ZHANG, Shi-ke HU

  理论物理通讯. 1990, 13(3): 383-392.

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  We discuss dimensional regularization and calculate the UV divergences up to three loops in the two-dimensional non-linear sigma model with torsion.
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  The Phase Structure of Z(N) Lattice Gauge Theories by Variational Cumulant Expansion

  Chi-min WU, Pei-ying ZHA0

  理论物理通讯. 1990, 13(3): 393-404.

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  In the variational cumulant expansion approach, we get the phase structure of Z(N) lattice gauge theories analytically in four dimensions. The comparison with MC data is also presented.
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  Low Frequency Circular Polarized Soliton in a Ferromagnetic System Under a Strong Bias Magnetic Field

  Ying WU, Kai-lun YA0

  理论物理通讯. 1990, 13(3): 405-408.

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  The derivative nonlinear Schrodinger equation for the low frequency circular polarized wave, propagating parallel to the bias magnetic field in a ferromagnetic system, is derived by the reductive perturbation expansion method.
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  Investigation of the Occupation Function of Localized States in Amorphous Semiconductors Under Infrared-Light Excitation

  LIU Xu-feng, XU Zheng-yi

  理论物理通讯. 1990, 13(3): 409-414.

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  The occupation function of localized states in a-Si:H under i.r. light excitation is directly calculated from the observed infrared-stimulated photocurrent spectra. The calculated occupation function in dual-beam and one-beam excitation cases are compared. The overshot phenomenon in the dual-beam experiment is explained as the result of the difference of the initial condition between two cases when i.r. light is turned on. In the dual-beam excitation case, at the beginning, in the upper part of the band gap, there are many trapped electrons to be excited into the conduction band to cause the photoconductivity overshot.
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  The Energy Levels of a Surface Hydrogenic Impurity in an Arbitrary Strength Magnetic Field

  SHEN Zhong-jun, ZHANG Shu-an, GU Shi-wei

  理论物理通讯. 1990, 13(3): 415-418.

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  The strong-perturbation theory is employed to calculate the energy levels of a hydrogen-like system at the surface in a constant magnetic field of arbitrary strength.
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  Chiral Soliton with Influence on Sea Quark

  ZHANG Jian-wei, HOU Ren-chang, QIU Xi-jun

  理论物理通讯. 1990, 13(3): 419-424.

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  The solution of the chiral soliton with influence on the sea quark is studied in the one-loop approximation. The coupled equations of the motion for the quark and the chiral field are solved numerically by the self-consistent iterative method. The exact quark density of a hedgehog baryon is compared with the results of two kinda of approximations for the chiral angle. It is found that the influence of the chiral soliton on the sea quark can not be ignored.in the calculation of the energy structure or the distribution of the quark density of a baryon.