1983年, 第2卷, 第3期　
刊出日期：1983-05-30

  

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  A CLUSTER MODEL METHOD AND ITS APPLICATIONS TO CHEMISORPTIONS ON SEMICONDUCTOR SURFACES

  张开明, 徐永年, 谢希德

  理论物理通讯. 1983, 2(3): 1065-1073.

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  In the present paper the cluster model and charge self-consistent method are used to study the chemisorpti on Si(lll1), Ge(111), and GaAs(110) surfaces. The parameters in the calculations are selected to fit the respective bulk energy bands of Si, Ge, and GaAs. Some general rules of chemisorpti on Si(ll1) and Ge(ll1) are investigated and speculated. The three-fold hollow site geometry is favorable for group iii metals on Si(lll), whereas the one-fold top site is more stable for group vii elements, the reason being probably one of the favorable charge distribution. However, the situation for chemisorpti on Ge(ll1) is somewhat different. The adsorptions of group iii and v elements on GaAs(110) are also considered. The possible chemisorption geometries and the related electronic states for these systems are calculated and discussed.
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  U-SEQUENCES IN THE PERIODICALLY FORCED BRUSSELATOR

  郝柏林, 王光瑞, 张淑誉

  理论物理通讯. 1983, 2(3): 1075-1080.

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  We show numerical evidence of exact U-sequences in the periodically forced trimolecular model (the forced Brusselator). Interspersed among period-doubling bifurcation sequences star-ting with RLⁿ type periods, there are chaotic regions bounded on one side by period-doubling bifurcation sequences and on the other side by intermittent transitions. Along certain directions in the parameter space the most clearly seen periods appear in the same order as that in the logistic map, but along other directions the U-sequences may fold and give rise to deviations from the standard patterns. Our results show the coexistence of different "routes to chaos" in one and the same matheatical model and the necessity to enlarge the parameter space in both real and computer experiments on chaotic transitions.
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  THE QUANTUM ELECTRODYNAMICS IN A CONSTANT MAGNETIC FIELDTHE PERTURBATION THEORY IN FURRY PICTURE⁺

  宋燠

  理论物理通讯. 1983, 2(3): 1081-1097.

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  The second guantization in furry picture is carried out, the perturbation theory is built up and a new method for investigating the electromagnetic phenomena in a constant magnetic field is proposed in this paper. Since the treatment of this method is exact, it is especially suitable for very high magnetic fields.
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  THE MULTI-FOLD COMMUTATOR OF VARIATION OF POTENTIAL IN CHIRAL MODEL AND SDYM FIELD

  葛墨林, 王均义, 吴泳时

  理论物理通讯. 1983, 2(3): 1099-1106.

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  The multi-fold commutaror representation of hidden symmetry algebra in principal chiral model and the self-dual Yang-Mills field is explicitly shown. All the variations are taken with respect to the potential A_ξ other than field quantity g for principal chiral model in defining the usual operator Q(ξ,η) to give the G⊗c(t) algebra.
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  THE QUARK MASS EFFECT OF THE DISTRIBUTION AMPLITUDES IN γγ-EXCLUSIVE PROCESSES

  黄涛, 石最坚

  理论物理通讯. 1983, 2(3): 1107-1113.

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  In this paper we have analyzed the γ^*π°→γ, γγ→ππ and γγ→ρρ processes by using the sum rules of the distribution amplitude ФM(xi,Q²), which are obtained from the π°→γγ and the π→μν decay processes. Since the angular distributions of the γγ→π°π° and γγ→ρ_⊥ρ_⊥ amplitudes are sensitive to the shape of the distribution amplitude ФM(xi,Q²), there is a possibility to investigate the effect of the quark mass from the angular distributions of γγ→MM exclusive processes.
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  INSTABILITY OF THE MEAN FIELD VACUUM IN LATTICE GAUGE THEORIES

  郭硕鸿, 陈启洲, 刘金明, 纪哲锐

  理论物理通讯. 1983, 2(3): 1115-1119.

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  We calculate the interaction energy between heavy quark pair in the Hamiltonian formulation of lattice gauge theories. Mean field-variational calculations show that the upper limit of the string tension is zero in the weak coupling region if we use approximate vacuum state of the mean field type. The mean field vacuum is unstable against forming closed flux loops.
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  A STUDY OF THE REACTION K^-P→ΦΛ AC 4.2GeV/c

  Mujahid Kamran

  理论物理通讯. 1983, 2(3): 1121-1127.

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  The high statistics differential cross section, polarisa-tion and density matrix data on K^-P→ΦΛ obtained by the AmsterdamCERN-Nijmegen-Oxford collaboration at 4.2GeV/C is analysed using a Regge pole model with evasive Regge contribu-tions. The exchanges invoked are the K*, K**, K,KA and K_Z The K*-K** exchanges are taken to be non-degenerate and a simplifying assumption on their couplings in O+ζ→O+ζ reactions, advocated recently by Saleem and collaborators, is generalised to the present case. We do not find any need for the K_B in fitting data.
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  RADIATIVE DECAYS OF CHAKMONIUM AND CONSTITUENT QUARK MASSES

  赵光达

  理论物理通讯. 1983, 2(3): 1129-1135.

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  The problems of both El and M1 transitions of charmonium are discussed in the nonrelativistic potential model. It is found that these problems could be resolved by assuming larger constituent quark masses. With m_c=2.50GeV, m_b=5.84GeV in the typical linear plus Coulomb potential model we get satisfactory results for the mass spectra, the El and M1 transition rates, and the relative values of leptonic widths for the ψ and T families. The implication of the large constituent quark masses is also discussed.
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  IRREDUCIBLE REPRESENTATIONS OF SUPERALGEBRAS B(1,l) AND B(0,2)

  韩其智, 孙洪洲

  理论物理通讯. 1983, 2(3): 1137-1144.

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  In gauge supersymmetry and supersymmetry of nuclei we often meet the superal gebra osp(m/2n). Only the irreducible representations of osp(l/2) B(0,l) have been constructed so far^[1]. Here we construct all the finite-dimensional irreducible representations of osp(3/2)=B(l,l) and osp(l/4)=B(0,2), The conditions of grade star representations are discussed. Only a part of finitedimensional irreducible representations of B(1,1) and B(0,2) are grade star representations. These are different from those of B(0,l).
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  A MODEL OF NEUTRINO STELLAR SYSTEM AND THE UPPER BOUND OF NEUTRINO MASS OBTAINED FROM THE RCTATION CURVES OF SOME GALAXIES

  庆承瑞, 何炸麻, 张元仲

  理论物理通讯. 1983, 2(3): 1145-1151.

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  We discuss in this paper a stellar model of degenerate massive neutrinos with a core made of heavy matter. Dimension of the core is much smaller than the scale of neutrino star. The Oppenheimer-Volkoff equation is solved for such a system. Our calculation shows that under certain conditions, this neutrino halo will resemble a pure neutrino star. We have further obtained insides the neutrino star (or halo) the rdtation curve and the gravitational red shifts. It is interesting to note that the relative rotation velocity v(r)EV(r)/V(R) (R is the radius of the neutrino star) depends only on the relative coordinate ξ=r/R in the nonrelativistic cases. Therefore, all nonrelativistically degenerate neutrino systems will have a universa1 relative rotation curve(v versus ξ). Within the accuracy of numeri calcalculation, we have also obtained a useful relation connecting the maximum velocity V_m and the corresponding coordinate R_m as V_mR_m2=0.231. By comparing this relation with the observed rotation data at large distances for some galaxies, we have obtained an upper bound for neutrino mass of about 6-9eV.
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  EXPONENT BEHAVIORS OF SINGLE MODE LASER SYSTEM WITH SATURABLE ABSORBER NEAR THRESHOLD

  刘建民

  理论物理通讯. 1983, 2(3): 1153-1156.

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  In this letter we discuss the exponent behaviors near a threshold of single mode laser system in the presence of a saturable absorber. Four threshold exponents, β,δ,γ and α, and four threshold amplitudes B,D,г and A are obtained. They obey the generalized scaling laws of z=4.
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  A PHASE TRANSITION MODEL WITH PERPETUAL ORDER

  孙鑫

  理论物理通讯. 1983, 2(3): 1157-1160.

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  A simple model is given to show there exists a kind of phase transition for which the order parameter never vanishes; its characteristic is the second derivative of the order parameter rather than the order parameter itself, and its critical behavior satisfies the scaling.
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  ON THE EXTERIOR SOLUTIONS OF A CHARGED MASS POINT IN GAUGE THEORIES OF GRAVITATION

  张元仲

  理论物理通讯. 1983, 2(3): 1161-1163.

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  In a case of spherically symtric and static field, exterior solutions of a charged mass point for the nine-parameter R+R² gravitational theories are investigated. We obtain results as follows: in the case of coupling constant (zP-2r+s)=0, solution without torsion is the Reissner-Nordstrom metric; otherwise there is no solution with vanishing torsion.
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  A TROUBLE FOR COMPOSITE QUARK AND LEPTON MODELS

  朱重远

  理论物理通讯. 1983, 2(3): 1165-1168.

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  In composite quark and lepton models a factor which depends on the quark or lepton mass ratio appears in the effective weak coupling constant of quarks and leptons. It comes from the Lorentz (contraction of the composite quark and lepton wave functions and may cause a trouble for their weak coupling constant universality.
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  INVERSE SCATTER1 NG TRANSFORM AND REGULAR RIEMANN-HILBERT PROBLEM

  王世坤, 郭汉英, 吴可

  理论物理通讯. 1983, 2(3): 1169-1173.

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  It is shown that the inverse scattering transform method for solving the Lax pair of given nonlinear evolution equation can be reduced to a kind of Riemann-Hilbert (RH) problem of meromorphic functions with respect to the complex spectral parameter. The RH problem is generally regular no matter solitons are involved or not. The linear singular integral equation associated with the RH problem has been derived, which is essential1y equivalent to the Gel fand-Levitan-Marchenko equation.Furthermore, the regtllar RH problem satisfied by the Sacklund transformation from a fundamental solution set of the eigenvalue equations of Lax pair to a new set has Fen given as well. The RH problem reduced from the inverse scattering transform is in fact a special case of that satisfied by the Backlund transformation.