1997年, 第28卷, 第2期　
刊出日期：1997-09-15

  

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  An (n+1)-Dimensional Integrable Model: Painlevé Test

  LOU Senyue

  理论物理通讯. 1997, 28(2): 129-132.

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  A (3+1)-dimensional model is proposed at first. The integrability of the model is proved by using the standard Painlevk analysis. Then the model is extended to (n + 1)-dimensional case. The model is space-isotropic and is a type of the modified KdV extension in higher dimensions.
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  R-Line Thermal Shift and Thermal Broadenings of R, R',and B Lines for Ruby

  CHEN Jurong, MA Dongping, LIU Yanyun

  理论物理通讯. 1997, 28(2): 133-138.

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  The unified theoretical calculation of thermal shifts (TS) of R₁ and R₂ lines and thermal broadenings (TB) of R, R' and B lines for ruby was carried out for the first time.The calculated results are in very good agr&ment with a great number of experimental data. Especially, by using quantum theory and taking into account all the admixtures of wavefunctions within d³ electronic configuration, all the TM in electron-phonon interaction (EPI), the electronic energy spectrum and lattice-vibration Spectrum, the very important contributions to TS and TB from single-phonon direct process were theoretically calculated in detail. The microscopic essentials of various contributions are revealed, and the mistakes in previous work are remedied.
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  An Alternative Approach to Jaynes-Cummings Model with Dissipation at Finite Temperature

  KUANG Leman, CHEN Guanghong, GE Molin

  理论物理通讯. 1997, 28(2): 139-148.

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  An alternative approach to the Jaynes-Cummings model (JCM) with dissipation at a finite environmental temperature is presented in terms of a new master equation under Born-Markovian approximation. An analytic solution of the dissipation JCM is obtained. A variety ofphysical quantities of interest are calculated analytically. Dynamical properties of the atom and the field are investigated in some detail. It is shown that both cavity damping and environmental temperature strongly affect nonclassical effects in JCM, such as collapse and revivals of the atomic inversion, oscillations of the photon-number distribution, quadrature squeezing of the field and sub-Poissonian photon statistics.
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  Calculation of the Storage Time of the Ions Confined in a Paul Trap

  LUO Xueli, ZHU Xiwen, WU Dajin

  理论物理通讯. 1997, 28(2): 149-156.

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  A Brownian motion model for the energy of the ions trapped in the pseudopotential well of a Paul trap is proposed and the exact solutions of the storage time in terms of the mean first passage time (MFPT) in the cases of white noises and colored noises are theoretically calculated. The relationships with the damping coefficient, noise parameters and the energy distribution of the ions are also discussed.
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  The Modes of Internal Motion and Classification of a Three-Electron State in Quantum Dots

  LI Xungui

  理论物理通讯. 1997, 28(2): 157-166.

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  The physics underlying the low-lying states of a three-electron system (S = 1/2, L = 0 to 6) confined in a two-dimensional quantum dot by a parabolic potential has been investigated. The modes ofinternal motion in the low-lying states have been identified based on an analysis of the inherent nodal surfaces originating from the quantum mechanical symmetry. Furthermore, a classification for the low-lying states has been proposed.
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  Plasmons in Finite Three-Tile Quasiperiodic Superlattices: On-Site Model

  LIU Nianhua, FENG Weiguo, WU Xiang

  理论物理通讯. 1997, 28(2): 167-172.

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  We investigate the plasmon spectrum of a finite semiconductor superlattice in which the quantum wells are located at periodic sites but the electron densities are arranged in a three-tile quasiperiodic sequence. It is found that the branching rule of the on-site model is different from that of the transfer model. The quasiperiodic arrangement of the electron densities results in a number of surface modes. The localization of the modes is discussed.
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  Retrieval Properties of the Neural Networks with Clipped Synapses

  HU Beilai, CAO Xihui

  理论物理通讯. 1997, 28(2): 173-178.

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  The exact pardel dynamical equation for a diluted, dipped Hopfield neural network is derived by prol;abilistic approach. The retrieval properties of the network are discussed in detail. The presented results show that the clipped synapses strongly influence the dynamical behavior and retrieval properties of the network, which make the size of retrieval attractor smaller. The maximum critical loading capacity a_c = 0.40 for the clipped network is observed.
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  Phase Dynamics in Nonlinear Coupled Oscillators

  WANG Kaige, WANG Jian, YANG Guojian

  理论物理通讯. 1997, 28(2): 179-186.

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  We discuss the phase dynamics in the system of a set of nonlinear coupled oscillators. We find a direct and simple geometric method to observe the geometric phase for this system, and it provides a possibility for the experimental measurements.
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  Quantum Statistical Properties of Even and Odd qs-Coherent States

  WANG Jisuo, SUN Changyong

  理论物理通讯. 1997, 28(2): 187-190.

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  In this paper, we use the numerical method to study the influences of q and s deformations on the quantum statistical Properties of even and odd qs-coherent states. It is shown that nonclassical properties of the even and odd qs-coherent states are very different from those of the usual even and odd coherent states. It is found that squeezing and antibunching effect appear for both even and odd qs-coherent states in some range of the parameters q, s and r. The smaller the q (q < 1) and s are, the.Jarger the difference between the even and odd qs-coherent states and the usual even and odd coherent states is.
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  On q-Defomed Creation Operator α

  YANG Yaping, ZHAO Chunfeng, YU Zurong

  理论物理通讯. 1997, 28(2): 191-194.

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  In this paper, we construct the eigenstate of q-deformed creation operator α by using the contour integral representation of δ function. Some of its properties are presented.
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  The Effects of Vacuum Fluctuations on ρ Meson Masses in Hot and Dense Matter

  ZHANG Yijun, GAO Song, SU Rukeng

  理论物理通讯. 1997, 28(2): 195-200.

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  Based on the thermo field dynamics, the temperature- and density-dependent effective mass and screening mass of ρ meson in the vector-tensor ρ-meson-nucleon-nucleon coupling model have been calculated. The effects of the vacuum fluctuation corrections through the effective nudeon mass are examined. We have shown that the vacuum fluctuation gives an important correction to the self-energy of ρ meson and leads to a reduction of ρ-meson mass in hot and dense matter.
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  The Q-Effect of the Structures of Three-Body Systems

  XIE Wenfang, BAO Chengguang

  理论物理通讯. 1997, 28(2): 201-206.

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  By making use of two different modes, we made further investigation of how the competition between internal vibration energy and collective rotation energy affects the geometric structures and internal motions of three-body systems.
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  The Density Effects on the Thermal Production Rate of Dilepton in QGP

  GAO Song, SU Rukeng, LI Xueqian

  理论物理通讯. 1997, 28(2): 207-216.

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  In the framework of the thermo field dynamics (TFD) we discuss thermal production of dileptons in quark gluon plasma (QGP) of finite temperature and density up to the first order of QCD correction. We show that the temperature effect to the thermal production rate is rather different from that of the chemical potential, in fact, they give rise to opposite effects which may influence the observation of the dilepton production in QGP.
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  Complex Chiral Bosons and Their Weyl Fermionic Representation

  MA Zhongshui

  理论物理通讯. 1997, 28(2): 217-220.

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  The complex chiral boson model is proposed. We quantize the theory by using Dirac algorithm and discuss the BRST aspects of the complex chiral boson theory. It is also shown that at the quantum level the theory can be expressed in terms of a Weyl fermionic representation. This suggests that the chiral bosons and Weyl fermions in two dimensions be equivalent in their dual form.
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  Nontrivial Q²-Dependence in the Gottfried Sum Induced by Nonperturbative Effect

  YANG Jianjun, MA Boqiang, LI Guanglie

  理论物理通讯. 1997, 28(2): 221-224.

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  In consideration of the lowest dimensional condensate contributions to the free quark propagator, we obtain the nonperturbative quark propagator with the nonvanishing vacuum average value for quark composite operator (|qq|), Using the -corrected quark propagator and basing on the simple quark-parton model, we discuss the nonperturbative effect in the nucleon structure function. It is shown that the nonperturbative effect modifies the conventional quark-parton model formula of the nucleon structure function at finite Q² and suggests a nontrivial Q²-dependence in the Gottfried sum.
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  Nonlocal Scalar Electrodynamics from Chern-Simons Theory

  LIN Qionggui

  理论物理通讯. 1997, 28(2): 225-230.

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  The theory of a complex scalar interacting with a pure Chern-Simons gauge field is quantized canonically. Dynamical and nondynarnical variables are separated in a gaugeindependent way. In the physical subspace of the full Hilbert space, this theory reduces to a pure scalar theory with nonlocal interaction. Several scattering processes are studied and the cross sections are calculated.
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  The Two-Variable Coherent States of the Quantum Algebra su_q(l,1)

  GONG Renshan

  理论物理通讯. 1997, 28(2): 231-236.

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  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.
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  Total Photoabsorption Cross Section and Excitation Function in the Quasi-Deuteron Energy Region

  U. Lucia

  理论物理通讯. 1997, 28(2): 237-240.

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  In photofission a lot of studies have been made to analyze the energy of the nuclei to understand their inner structure. The relevance of the excitation function has been pointed out. The Rami J tonian of interaction for the photofission was deduced and connected to the excitation function.
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  Convergence of the Variational Cumulant Expansion

  CHEN Ying, ZHU Yunlun

  理论物理通讯. 1997, 28(2): 241-244.

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  In this article we discuss the convergence of the variational cumulant expansion (VCE) in the Ising model and lattice φ⁴ model. We find that in critical region VCE results do not converge so quickly as elsewhere and the analyticity of thermo-dynamical functions and the strong correlation in the critical region are responsible for this fact.
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  An Analytical Study of the O(N) Nonlinear σ Models on Lattice

  ZHAO Peiying, WU Jimin

  理论物理通讯. 1997, 28(2): 245-248.

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  In the variational cumulant expansion approach, we calculate the internal energy for the d-dimensional O(N) nonlinear σ models on lattice. Specially, we give the results for two-dimensional O(3), O(4) and O(5) models. A comparison with Monte-Carlo (MC) data is also presented. Our formalism can given the results for O(N) nonlinear σ models (for any N and any dimensionality d) straightforwardly.
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  Three Formulations of Jeans Rule

  GAO Chongyi

  理论物理通讯. 1997, 28(2): 249-252.

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  Jeans rule can be formulated in the forms of velocity, height and energy. These forms are completely equivalent and can be taken freely. Taking the standpoint of energy,Jeans rule can be explained more easily.
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  Solit on Model for Energy Transport in Collagen Molecules

  XIAO Yi, LIN xianzhe

  理论物理通讯. 1997, 28(2): 253-256.

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  A new possible channel for energy transport in collagen molecules is proposed. Based on this channel, a three-chain model of a collagen molecule is presented. Soliton dynamics of this model is investigated for symmetric and asymmetric cases.