1992年, 第17卷, 第2期　
刊出日期：1992-03-15

  

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  Flux States, Anyons and High T_c Superconductivity

  Jian-Bin WU, Wen-Zhou LI, He-Ping YING, Qian NIU

  理论物理通讯. 1992, 17(2): 129-138.

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  In this paper, we studied the statistical behavior of anyons with isospin degrees of freedom, in which the fluctuation of isospjn degrees of freedom satisfies the O(3) nonlinear σ model. Under the mean field treatment, this model is in somewhat equivalent to the doped or frustrated Heisenberg an tiferromagnetic (AFM) model. We also studied the relation between the statistical field A_μ, and Skyrmion current B_μ. Finally, we set up the relation between flux states and spinon statistics, and the conditions of Bose condensation of holons. In particular, for π-flux state of A_μ, the spinons are bosons, the holons satisfy 2/3 fractional statistics.
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  Envelope Solitons of the High Frequency Extraordinary Waves in Ferromagnetic Systems

  Ying WU, Xiao-Xue YANG

  理论物理通讯. 1992, 17(2): 139-144.

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  It is shown thatJhe high frequency extraordinary waves, propagatingperpendicular to the dc magnetic field in ferromagnetic systems, are governed by the nonlinear Schrsdinger equation and are modulationally unstable and may-evolve as solitons.
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  Reflection of Electrons from a Fibonacci Coupled Quantum Dots System

  Wen-Sheng PING, Wei-Guo FENG, Xiang WU

  理论物理通讯. 1992, 17(2): 145-150.

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  The reflectivity of electrons from a kind of quasi-period one-dimensional system is investigated. This system consists of a sequence of Fibonacci coupled quantum dots. Using the transfer-matrix method, and taking account of the experimental technique, we proposed the formalism of the electron reflection rate for the chain of quantum dots. fiom the numerical results, we analyzed the influences of the generation number, the transmission rate of single quantum dot and the phase for reflection amplitude, and we found that the reflection spectra of the system have a rich structure of self-similarity.
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  Computation of Dimensions for Strange Attractors by the Box Counting Renormalization Method

  Wei-Ming YANG, Wei-Mou ZHENG

  理论物理通讯. 1992, 17(2): 151-156.

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  The scaling ansats for box counting functions is verified numerically for the reverse doubling sequence of the logistic map. A box counting renormalisation method is developed to calculate dimensions for strange attractors.
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  Multiple Exchange-Mediated Interaction and Superconductivity

  Fu-Sui LIU

  理论物理通讯. 1992, 17(2): 157-166.

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  It is shown that in a strongly correlated system there exists multiple exchange-mediated interaction (MEIW). From the numerical calculations of T_c, (T_c vs. x and y for La_2-xSr_xCuO₄ and Y₁Ba₂Cu₃O_7-y), the small isotope effect, the large gap and some explanations for the observed phenomena, this paper affirms that the high-T, superconductivity is caused by the MEIW, the phonon-mediated interaction and the tunneling coupling. The heavy-fermion superconductivity is mainly caused by the MEMI, and, in the meantime, the phonon-mediated interaction h h also some contributions. The extremely large gap below T_N in AF Chevrel phase, some AF materials come from the MEMI. The organic superconductivity might be caused mainly by the MEMI.
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  Symbolic Dynamics for the Tél Map

  Wei-Mou ZHENG

  理论物理通讯. 1992, 17(2): 167-174.

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  In terms of contracting and expanding foliations the two-dimensional Tél map is decomposed into two coupled one-dimensional maps. Symbolic sequences are assigned to the two classes of foliations, and their ordering is discussed. The pruning front is constructed. A necessary and sufficient condition for admissible sequences is proposed.
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  Algebraic Approach to Gauge Theory and Its Non-Commutative Extension

  Ke WU, Ren-Jie ZHANG

  理论物理通讯. 1992, 17(2): 175-182.

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  We propose an alternative algebraic construction of the connection theory on the fiber bundle, and find its non-commutative extension, i.e., the connection theory based on guantum groups. In thb construction, the Yang-Baxter equation arises ae the exchange relations of connections and a deformed trace of quantum groups is introduced to build up the characteristic classes.
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  Quantum Groups and Spectra of Diatomic Molecules

  Zhe CHANG, Han-Ying GUO, Hong YAN

  理论物理通讯. 1992, 17(2): 183-204.

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  We briefly review and further investigate the quantum group theoretic approach to the spectra of the diatomic molecules presented by the authors recently. The vibration-rotational structures as well as the interactions of vibrations and rotations are described in the quantum group theoretic approach satisfactorily. When nylor expanded, the analytic formulae of the new approach reproduce the results of nonlinear vibratingrotator model. For some particular states of randomly selected molecules, the parameters of the new approach are computed to fit the phenomenological data to high accuracies. We also supply an analysis of the (pseudo-) potential implied in the new model, and compare it with the conventional model of the local potential that is applied in the explanation of the Dunham formula of energy spectra.
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  Massive Yang-Mills Field Theory with Conformal (Weyl) Invariance

  Shu-Cheng ZHAO

  理论物理通讯. 1992, 17(2): 205-210.

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  A massive Yang-Mills field theory with the conformal (Weyl) invariance^[1] and gauge invariance is proposed. It involves the gravitational and various gauge interactions, in which all the mass terms appear as the uniform interactional form m(x) = KΦ(x). When the conformal and gauge symmetries are broken spontaneously, the Einstein gravitation emerges and all the fields obtain masses, this theory is renormalizable and unitary with the gravitation ignored. Finally we give a relation between the theory and the Higgs mechanism.
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  Conformal Affine Toda Fields from a Gauged WZNW

  Liu CHAO

  理论物理通讯. 1992, 17(2): 211-218.

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  The general conformal affine Toda (CAT) fields are derived as the result of imposing the constraint explicitly on the gauged WZNW action. The reduction procedure naturally indicates the integrability of the resulting system. The action, equations of motion, canonical Poisson brackets for this system are derived from WZNW model. The energy momentum tensor is derived also and is shown to be traceless after being improved.
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  Drift-Alfven Vortex in Low β Magnetized Plasma

  Yin-Hua CHEN, Ji-Xing LIU

  理论物理通讯. 1992, 17(2): 219-224.

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  Nonlineaidrift-Alfven waves in low β magnetized plasma are reconsidered. Sets of nonlinear equations describing drift-Alfven waves are derived and corresponding dipolar vortex solutions are given. The reault shows that the solution belongs to intrinsic magnetized vortex for which the corresponding perturbed magnetic field line and perturbed electric current on the boundary of vortex are continuous.
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  Hydrogen Chemisorption on Disordered Binary Alloys

  Zong-Xian YANG, Fu-He WANG, Tao ZHANG, Mian WANG, W.K. LIU

  理论物理通讯. 1992, 17(2): 225-228.

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  The one-dimensional tight-binding model and the Green's function method are used to study the chemisorption energy of an atomic H on disordered binary alloys within the average T-matrix approximation. The one-electron chemisorption theory is used to describe the chemisorption process. The chemisorption energy is calculated as a function of the concentration percentages of the two components of the disordered binary alloys. The effect of the surface segregation of the CuNi system is also investigated.
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  Donor Impurity States on Rough Semiconductor Interface

  Hong SUN, Shi-Wei GU

  理论物理通讯. 1992, 17(2): 229-234.

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  Ground state energies of shallow states of donor impurities on cosine-shaped, periodically rough interfaces formed by two isotropic semiconductors, such as GaAs/Ga_1-xAl_xAs or GaAs/vacuum, are calculated variationally with the approximation that the interfaces represent infinitely high potential barriers. The results show that changes in the ground state energies of in teriaces impurity states caused by rough in teriace are not negligible especially for GaAs/Ga_1-xAl_xAs interfaces with sharp or dense interface defects.
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  Critical Exponents of Fully Directed Flights: A Laplacian Transformation Method

  Jia-Fu WANG, Kai-Lun YAO

  理论物理通讯. 1992, 17(2): 235-238.

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  A Laplacian transformation method is presented for d-dimensional fully directed flights (FDFs) with continuous steplengths. The correlation exponents we obtained are in agreement with the simulation study for fully directed Levy flight and the analytical results for FDF on a simple lattice. We believe that all FDFs in isotropic space belong to the same universality class.
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  Fractal Dimensions of Correlation Clusters for Conformal Fields

  S.G. CHEN

  理论物理通讯. 1992, 17(2): 239-342.

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  The fractal dimensions of correlation clusters at the critical point of continuous phase transition are studied within the framework of conformal field theory. The generalized dimensions D_n(n = 2,3, …), the singularity strength a and its distribution f(α) are derived rigorously, and their meanings are discussed.
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  q-Analogue Charged Coherent State and SU(3) Charged, Hypercharged Coherent State

  Hong-Yi FAN, Chang-Pu SUN

  理论物理通讯. 1992, 17(2): 243-246.

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  We generahe the conception of q-analogue coherent state to the cases of charged coherent state and charged, hypercharged coherent state. Their explicit expressions in the ordinary Fock space are derived.
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  The Construction of q-Boson Realizations and q-Differential Realizations for Quantum Algebras

  Hong-Chen FU

  理论物理通讯. 1992, 17(2): 247-252.

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  A general method to construct the q-boson realixations and their corresponding q-differential realizations of quantum algebras is developed with SUq(2) as an example. All poeeible q-boson and q-differential realisations of quantum algebras can be obtained in this way.
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  Feynman Transformation Matrix Element for a type of Hamiltonian of Angular Momentum system

  Hong-Yi FAN

  理论物理通讯. 1992, 17(2): 253-256.

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  Using the technique of integration within ordered product (IWOP) of operators and the Schwinger boson representation for the angular momentum theory as well as the coherent state's method, we evaluate the Feynman transformation matrix element for the angular momentum system whose Hamiltonian is H = AJ_x + BJ_y + CJ_x (A, B, C real). The eigenstate of H is derived and the comparison between it and the SU(2) coherent state is made.