1994年, 第21卷, 第3期　
刊出日期：1994-04-30

  

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  Behavior of N-Mode Truncated Navier-Stokes ii Equations with External Force Acting on Various Modes

  Hai-Ping FANG

  理论物理通讯. 1994, 21(3): 257-262.

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  The fixed points of N-mode truncated Navier-Stokes equations on a two-dimensional torus with force acting on various modes are investigated. heir behavior is rather different. If the absolute value of the wave vector for the excited mode (|k|) is small, behavior of the fixed point P₀ (to be defined in the text) approaches a limit without involving many modes. If |k| is large enough, in order to get a stabilized behavior, a great number of modes must be considered. Furthermore, fien two or more modes are present in the external force, the behaviour of the truncated equations is rather different from that of the truncated system with one mode excited directly only. In many models there is no fixed point P₀ at all.
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  Photo-Induced Excitation States in Halogen-Bridgen Nickel Complexes

  Jing-Cui PENG

  理论物理通讯. 1994, 21(3): 263-268.

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  Photo-induced absorption in halogen-bridgen nickel complexes is investigated by applying a simple 314 filled two-band discrete tight-binding Hubbard model, and the numerical result is obtained by making use of Green's function. The mechanism ofphoto-induced absorption in nickel complexes is discussed in detail.
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  Properties of a Magneto-Exciton in a Quantum Well

  Bao-Hua WEI, Kin-Wah YU, Shi-Wei GU

  理论物理通讯. 1994, 21(3): 269-272.

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  The ground state energies of an exciton in a GaAs/Ga_1-xAl_xAs quantum well structure for perpendicular magnetic field of arbitrary strength are studied. The results show that the energy of the magneto exciton will be increased with the increase of quantum well width and magnetic field strength.
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  Study of Cyclotron Resonance of Interface Polarons

  Ze CHENG, Shi-Wei GU

  理论物理通讯. 1994, 21(3): 273-280.

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  This paper presents a study of the cyclotron resonance of the interface polarons in a semiinfinite polar crystal. In the resonant magnetic field region the Landau-level corrections due to the resonant coupling of the electron with the bulk longitudinal-optical (LO) phonon and the surface optical (SO) phonon are calculated. At resonance the n-th Landau level (n > 0) splits into a triplet. The cyclotron-resonance mass of the electron is evaluated for an arbitrary magnetic-field strength. For the interface system the magneto-optical anomalies display three branches of the cyclotron-resonance mass spectra. The numerical results show that in the interface system the polaron effect is weakened with respect to the ideal twodimensional system. It is found that in the very weak magnetic fields the polaron effect is contributed mainly by the SO phonons, whereas in the large magnetic fields the LO-phonon contribution to the polaron.effect becomes predominant.
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  Critical Percolation Probabilities for the Next-Nearest-Neighbouring Site Problems on Sierpinski Carpets

  Hong-Bing NIE, Bo-Ming YU

  理论物理通讯. 1994, 21(3): 281-288.

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  In this paper, we compute the next-nearest-neighbouring site percolation (Connections exist not only between nearest-neighbouring sites, but also between next-nearest-neigh bouring sites.) probabilities PC on the two-dimensional Sierpinski carpets, using the translationaldilation method and Monte Carlo technique. We obtain a relation among PC, fractal dimensionality D and connectivity Q. For the family of carpets with central cutouts,(1 - P_c)/(1 - P_c^s) = (D - 1)^1.60, where P_c^s = 0.41, the critical percolation probability for the next-nearest-neighbouring site problem on square lattice. As D reaches 2, P_c = P_c^s = 0.41, which is in agreement with the critical percolation probability on 2-d square lattices with . next-nearest-neigh bouring interactions.
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  The Plateau and Symmetrical Structure of Lyapunov Exponents in 2-Dimensional Homogeneous. Dissipative Map

  Bing-Hong WANG

  理论物理通讯. 1994, 21(3): 289-298.

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  The universal crossover behavior of Lyapunov exponents in transition from conservative limit to dissipative limit of dynamical system is studied. We discover numerically and prove analytically that for homogeneous dissipative two-dimensional maps, along the equal dissipation line in parameter space, two Lyapunov exponents λ₁ and λ₂ of periodic orbits possess a plateau structure, and around this exponent plateau value, there is a strict symmetrical relation between λ₁ and λ₂ no matter whether the orbit is periodic, quasiperiodic, or chaotic.The method calculating stable window and Lyapunov exponent plateau widths is given. For Hénon map and 2-dimensional circle map, the analytical and numerical results of plateau structure of Lyapunov exponents for period-1,2 and 3 orbits are presented.
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  On the Consistent Constraint of the Deformation Parameter for q-Deformed Quantum Mechanics

  Kang LI, Yi-Xin CHEN, Zhong-Shui MA

  理论物理通讯. 1994, 21(3): 299-302.

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  The region for q values has been clarified by keeping the requirement of the uncertainty relation in the q-deformed quantum mechanics.
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  R-Matrices for Some Inhomogeneous Quantum Groups

  Bin CHBN, Ke WU

  理论物理通讯. 1994, 21(3): 303-310.

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  In this paper, some new generalized inhomogeneous quantum groups corresponding to the homogeneous multiparameter quantum groups GL_X,qij(N)are constructed, furthermore,the R-matrices for these inhomogeneous quantum groups are found.
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  Vector Coupling and Rho Meson in a Nonlocal Nambu-Jona-Lasinio Model

  W. Z. DENG, J. W. ZHANG, L. M. YANG

  理论物理通讯. 1994, 21(3): 311-316.

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  A vector coupling term apart from the scalar and pseudoscalar terms, is introduced into the nonlocal quark-(anti-)quark interaction in an extended Nambu-Jona-Lasinio model to investigate the vector rho meson mode in the relativistic random phase approximation (RPA). It is shown that a favorable choice of the vector coupling to fit the empirical data has to be the same form as that of the original scalar and pseudoscalar ones but with a necessary negative sign.
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  Monte Carlo Code ODIN and Energy Density Analysis in Relativistic Heavy Ion Collisions

  Soren P Sorensen, Wei-Qin CHAO

  理论物理通讯. 1994, 21(3): 317-326.

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  The energy density reached in relativistic heavy ion collisions is analyzed based on the Monte Carlo code ODIN. The effect of different parameters in ODIN code on the energy density is investigated. The results show that the actually reached energy density is lower than Bjorken's estimation due to the finite collision time.
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  The Odd-Even Differences of Nuclear Moment of Inertial

  Fu-Xin XU, Gong-Xing SUN

  理论物理通讯. 1994, 21(3): 327-332.

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  In this article, the odd-even differences of nuclear moment of inertia are systematically analyzed and calculated. The results show that when the odd nucleon is in high-j intruderorbit or in the lowest orbit from the spherical shell, the odd-even differences are very large. Besides, something new are found in our studies.
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  The Quarkonium Potential Within the Short and Intermediate Range in QCD

  Jian-Guo BIAN, Tao HUANG, Qi-Xing SHEN

  理论物理通讯. 1994, 21(3): 333-340.

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  A quark-antiquark potential is calculated by involving vacuum condensates up to dimension-6 in QCD in the background fields. The underlying assumption is that a gluon (quark) propagates, not in the empty space, but through the physics vacuum, filled with the background fields. The interactions of the gluon with the background fidds manifest themselves as the corrections of vacuum condensates to the free gluon propagator. It is shown that these corrections extend the potential from the short distances to the intermediate range. Indeed, with some reasonable parameters, the resulting potential is similar to those popular phenomenological potentials in shape in the region of 0.1 < γ < 1 fm.
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  Variational Cumulant Expansion on SU(2)⊗ SU(2) Chiral Model

  Liang-Xin HUANG, Tian-Lun CHEN

  理论物理通讯. 1994, 21(3): 341-348.

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  The phase transition of the two-dimensional SU(2)⊗ SU(2) lattice chiral model has been studied by a variational cumulant expansion method. The internal energy and the specific heat are calculated to the 4th order correction and they are in good agreement with the Monte Carlo (MC) resdits. Except the behavior of the crossover region, similarities between this model and the four-dimensional SU(2) lattice gauge model are also discussed.
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  A New Way of Bosonic Structure of Fermions

  Tu-Nan RUAN, Si-Cong JING, An-Min WANG

  理论物理通讯. 1994, 21(3): 349-352.

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  We propose a new approach to construct fermions in terms of usual bosons. The operator and normal product forms of the bosonic structure of fermions are obtained, and the extension of the method to many degrees of freedom and field theory is also given.
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  The Soliton-Like and instant on-Like Solutions of the Generalized ξφ⁶ Model

  Sen-Yue LOU, Guang-Jiong NI

  理论物理通讯. 1994, 21(3): 353-360.

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  The well-known ξφ⁶ scalar field model is extended to a more general form. It is shown that there exist various types (both topological and nontopological) of the soliton-like and instanton-like solitary wave solutions for the generalized ξφ⁶ model. Some special types of solutions of the conventional ξφ⁶ model can be transformed to that of the extended ξφ⁶ model with an arbitrary constant and then various cnoidal waves of the extended modei are also obtained. Especially, a large number of model-independent soliton-like, instanton-like and cnoidal wave solutions, which are the same as that of the usual ξφ⁶ model, are allowed.
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  Intrinsic Loop Regularization and Renormalization in φ⁴ Field Theory

  Zhong-Hua WANG, Han-Ying GUO

  理论物理通讯. 1994, 21(3): 361-368.

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  We find that there exist certain intrinsic relations between the divergent diagrams and the convergent ones at the same loop order in some renormalizable quantum field theories. Whereupon we propose a new method for regularization and renormalization of those divergent diagrams. ,We name it the intrinsic loop regularization. In this paper, we take the renormalized φ⁴ theory up to the second order of the coupling constant as an example to present this method.
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  Relation Between Shape Equations for Axisymmetric vesicles

  Wei-Mou ZHENG, Ji-Xing LIU

  理论物理通讯. 1994, 21(3): 369-380.

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  In deriving the shape equation for axisymmetric vesicles from the Helfrich free energy the variation must be taken with respect to the contour. It is pointed out that the widely used Helfiich shape equation and the other one given by Peterson were derived by improper variations, hence both equations need to be examined. The validity of the two equations is discussed based on analysis of their relation revealed by two derived first integrals. A newly found exact solution for the general shape equation is studied and the relation of this exact solution of spherical topology with that of the Helfrich shape equation is discussed.
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  The Screening Length in Quark-Gluon Plasma and J/φ Suppression

  Chao-Ran HU, Wan-Yun ZHAO

  理论物理通讯. 1994, 21(3): 381-384.

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  Perturbative methods are used to calculate the screening potential energy of a static quarkantiquark pair by considering the color-averaged Wilson line. Our results are in agreement with the current understanding of the behavior of QCD at high temperature, Comparison with a J/φ production experiment in ultra-relativistic heavy-ion collision is also discussed in thisletter.