1995年, 第24卷, 第3期　
刊出日期：1995-10-30

  

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  H₂O as a Three-Body system

  Guo-Chun QIU, En-Wei LIANG

  理论物理通讯. 1995, 24(3): 257-264.

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  The few-body method for treating water molecules is presented. H₂O can be regarded as a three-body system. The total three-body wavefunction is expanded in terms of the harmonic oscillator product states in the Jacobi coordinates. The binding energies are calculated by using a pairwise model potential in the variational approach. The geometry and modes of internal motion are analyzed by the shape density function. The results are E = -76.07 a. u, R_HO = 0.970 Å and ∠LHOH = 105.38°. These results are compared with some known calculations and experimental values.
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  Pair Fluctuation Theory of the Attractive Hubbard Model: A Unified Picture

  Shi-Min CUI

  理论物理通讯. 1995, 24(3): 265-276.

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  A three-dimensional attractive Hubbard model is investigated from a general point of view on the nature of pair fluctuations. A unified description is given for superconductivity on the basis of a functional integral formalism. By treating the pairing and particle density fluctuations on the same footing, we obtain a comprehensive, thermodynamically consistent theory for this model. It is applicable in the entire range of input parameters and is exact in both the weak- and strong-coupling limits.
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  Effects of the Fluctuations on Thermodynamic Properties of the Mixed Valence Compounds

  Liang-Bin HU, Fu-Ming YANG, Tsung-Han LIN

  理论物理通讯. 1995, 24(3): 277-290.

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  Based on the SU(Nd) Anderson lattice mode1 in the slave boson formalism, westudy the effect of fluctuations around the saddle-point approximation on the thermodynamic properties for mixed valence lattice systems. The fluctuation component of slave boson field is explicitly introduced and its interactions with electrons are studied. By using the Green's function technique we obtain modified self-consistent equations of mean-field parameters and free energy. The fluctuation correction to the pseudophase transition temperature is obtained, and the validity of the mean-field approximation is examined. In the limit of low energy and small moment um transfer, a fluctuation correction to the specific heat proportional to T3 lnT at low temperature is extracted. The chemical potential shift is also studied. In order to describe the thermodynamic properties correctly, it is important to determine the chemical potential shift properly.
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  Surface and Interface Optical-Phonon Modesin a Finite Four-Layer Heterostructure of Polar Crystals

  Jun-Jie SHI, Shao-Hua PAN

  理论物理通讯. 1995, 24(3): 291-298.

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  The dispersion relation and eigen vector for the surface and interface optical-phonon modes in a finite four-layer heterostructure of polar crystals have been derived by using the dielectric con tinu um model. Moreover, as practical examples, the dispersion relations for some interesting structures such as finite and semi-infinite step quantum wells and a semi-infinite single quantum well are given for the first time.
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  Systematics of Periodic Windows in the Double-Diffusive Convection System

  Z.H. LIU, H.P. FANG

  理论物理通讯. 1995, 24(3): 299-304.

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  The dynamics of truncated double-diffusive convection system on a parameter axis is studied with symbolic dynamics. It is found that the systematics of periodic windows interspersed in chaotic region for its one-dimensional (ID) return maps (to be defined in the text) can be fitted into the universal form for the ID mappings with two critical points and the antisymetric property.
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  The Mean First-Passage Time for Nonlinear Non-Markovian Continuous Noise

  Ming YANG, Li CAO, Da-Jin WU

  理论物理通讯. 1995, 24(3): 305-310.

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  A method for calculating the mean first-passage time for non-Markovian free processes driven by continuous noise is generalized to free process X(t)=g[F(t)] and unfree process X( t)=f[X(t)]g[F(t)] with nonlinear noise. When the switch distribution + rectangular, the exact analytic expressions of the mean first-passage time for free process X(t) = [F(t)]^m driven by nonlinear noise and X( t=) -k[X(t)]ⁿ[F(t)lm+ [F(t)]^m driven by both multiplicative and nonlinear additive noises are also given.
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  Fock Representations of Lie Algebras, Loop Algebras and Affine Lie Algebras

  Xu-Feng LIU, Min QIAN

  理论物理通讯. 1995, 24(3): 311-320.

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  Explicit Fock representations of the classical Lie algebras in terms of boson creation and annihilation operators with an arbitrary highest weight are derived, and a general rule to construct Fock represen tations of a loop algebra from a boson realization ofits corresponding Lie algebra is establislted. A new kind of lowest weight represen tations of the affine Lie algebras attached to the classical Lie algebras, which require a zero center, is also presented. Based on these, a simple affinization procedure is given to obtain the Fock representations of level 1 of these affine Lie algebras.
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  Relativistic and Thermodynamically Consistent Treatment for Finite-Volume Effect of Nucleons in Nuclear Matter (I) General Formulation

  Qi-Ren ZHANG

  理论物理通讯. 1995, 24(3): 321-330.

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  A previous thermodynamically consistent procedure for considering the finite volume effect of nucleons in nuclear matter is developed to be relativistic. Parameters are determined by fitting all five empirical data for normd nuclear matter. The resulting nuclear equations of state may be used in researches for neutron stars and for phase transitions between nuclear matter and quark-gluon plasma.
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  Photons, Dileptons and Hadrons Produced by Quark-Gluon Plasma

  Xiao-Ming XU

  理论物理通讯. 1995, 24(3): 331-338.

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  Altarelli-Parisi equations in perturbative QCD are applied to getting evolution equations of quark-gluon plasma. The equations describe the cooling process of quark-gluon plasma by emitting photons. The numbers of observable photons and dileptons are calculated directly from these equations. The cooled quark-gluon plasma hadronizes and the production rates of hadrons are calculated with separable scalar confinement potentials.
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  Three-Body Structure of ¹¹Li

  Yi-Wu DUAN, Si-Ping LI

  理论物理通讯. 1995, 24(3): 339-342.

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  A variational calculation for neutron rich nucleus l1 Li is made in the ⁹Li + n + n model. The ⁹Li-neutron and neutron-neutron interactions are chosen to be of the Gaussian potentials with a repulsive core and an attractive tail. The strlicture and interparticle correlations are studied. A direct verification supporting neutron halo structure is found by inspecting the correlated densities.
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  Thermodynamical and Chiral Limit in Computer Simulations of Lattice Quant um Field Theories

  Xiang-Qian LUO

  理论物理通讯. 1995, 24(3): 343-352.

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  The finite-size effects which appear in computer simulations of chiral-symmetry breaking in lattice gauge theory are analyzed. To reduce these systematic errors, a better method for extrapolating the chiral condensate to the infinite volume and chiral limit is proposed.
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  Heavy Hadron Spectra to the Order 1/M in Heavy Quark Effective Theory

  C.S. HUANG

  理论物理通讯. 1995, 24(3): 353-358.

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  The heavy meson and baryon spectra are studied to the order of 1/M_Q in heavy quark effective theory. A phenomenological formula for the dependence of the spectra on the isospin and strangeness of the light quark system contained in heavy hadrons is proposed and its predictions are in agreement with the present experimental data. The predictions of beauty hadron masses including the 1/M_Q corrections are given. The parameters of the order of 1/M_Q are estimated from phenomenological analyses.
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  The Contributions of PGBs in the One-Generation Technicolor Model on the Rare Decays t→cZ, cγ

  Xue-Lei WANG, Yi-Min ZHANG, Jin-Min YANG, Gong-Ru LU

  理论物理通讯. 1995, 24(3): 359-362.

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  The Contributions of PGBs in the One-Generation Technicolor Model on the Rare Decays Keeping all masses, we have calculated the contributions of PGBs in the one-generation technicolor model on the rare decays t→cZ, cγ. The branching fractions are B(t→cZ)～10^-7, B(t→cγ)～10^-8 in the most cases. The magnitude of these decays can be significantly enhanced by PGBs.
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  A Vector Dominance Model of the Radiative Decay ∑⁺ → pγ

  Xue-Lei CHEN, Chong-Shou GAO, Xue-Qian LI

  理论物理通讯. 1995, 24(3): 363-368.

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  In this work, we propose a new mechanism for the ΔS = 1 radiative decay ∑⁺ → pγ, where the reaction occurs via a decay to a proton and a virtual vector meson, which converts later into a real photon by virtue of the vector dominance mechanism. The numerical result shows that this mechanism may be the dominan t one, or at least, very important compared to the others. An implied direct CP violation is also discussed, its order is found to be 10^-4～10^-5
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  Transverse Motion of Energy on Reflection and Refraction of Electromagnetic Waves

  Xin-Ya LIU

  理论物理通讯. 1995, 24(3): 369-372.

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  The equation of motion of the centre of energy of the reflected and refracted electromagnetic waves on the interface of dielectric media is obtained, it is shown that the physical reason leading to the transverse shift (TS) is the spin-momentum coupling of the electromagnetic waves near the interface.
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  ξ(2230) Is Likely to Be a Glueball

  Kuang-Ta CHAO

  理论物理通讯. 1995, 24(3): 373-376.

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  On the basis of the recent results of ξ(2230) → π⁺π^-, pp and ξ(2230) → K⁺K^-, K_sK_s, measured by the BES Collaboration in J/ψ radiative decays, combined with the PSI85 experiment of pp → ξ(2230) → KK we argue that because of its very narrow partial decay widths to nn and KK (less than 1 MeV), its large production rate in J/ψ radiative decays (BR(J/ψ → γξ> 2.3×10^-3), and its flavor-symmetric couplings to ππ and KK, the ξ(2230) is very likely to to be a J^PC= (even)⁺⁺ glueball.
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  Relationship Between Negative Binomial State and SU(1, l) Coherent State and Its q-Deformed Generalization

  Hong-Yi FAN, Si-Cong JING

  理论物理通讯. 1995, 24(3): 377-380.

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  By choosing a suitable single-mode boson realization of SU(1,1) algebra we show that the associated SU(1,1) cohkrent state can be directly reformed as a negative binomial state. The q-deformed negative binomial state is introduced, and the relationship between this state and the SU_q(1,1) coherent state is also demonstrated.
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  Analysis of Relative Diffusion in Homogeneous Isotropic Turbulence

  Xiao-Hong WANG, Ke-Lin WANG

  理论物理通讯. 1995, 24(3): 381-383.

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  The relative diffusion in homogeneous isotropic turbulence is studied in this letter. The mean square of the separation (Y²)∝t³ has been shown by the mean-field approximation as well as the analysis based upon the assumption that the particle displacement has the Gaussian distribution. The analytical results are in agreement with the conclusion of Richardson 4/3 law.
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  Comment on the Comment on Weformation of Quantum Mechanics

  You-Quan LI, Zheng-Mao SHENG

  理论物理通讯. 1995, 24(3): 384-384.

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  This is a reply to the comment by Chung and Chung [J. Phys. A27 (1994) 50371. We point out that the discussion there is imperfect.