1993年, 第19卷, 第1期　
刊出日期：1993-01-30

  

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  Launching of Antiprotons from the Catching Penning Trap by Evaporation Method

  G.Z. LI, R. Poggiani, G. Testera

  理论物理通讯. 1993, 19(1): 1-12.

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  In this paper the launching of antiprotons from the catching Penning trap by evaporation method has been studied. The distributions of velocity and time-of-flight spectrum of launching antiprotons depend on the methods of reducing the trapping electric potential.
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  Local Bifurcations of Equilibria of Ordinary Differential Equations

  Gang HU, Shun-Quan ZHU

  理论物理通讯. 1993, 19(1): 13-20.

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  The complete bifurcation set of equilibria of multi-dimensional ordinary differential equations is generally provided via explicit criteria. A comparison of our criteria with the Routh-Hurwith theorem is illustrated.
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  Symbolic Analysis of the Hénon Map at a = 1.4 and b = 0.3

  Hong ZHAO, Wei-Mou ZHENG

  理论物理通讯. 1993, 19(1): 21-26.

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  The symbolic dyhamics of the Lozi map is applied to the Hgnon map at a = 1.4 and b = 0.3. The fundamental forbidden zone, inside which points correspond to forbidden symbolic sequences, is constructed from a numerically determined bartition line. All the allowed periodic orbits up to period 7 are determined, and chaotic orbits are derived.
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  The Polaron Self-Energy in a Parabolic Quantum Dot

  Ka-Di ZHU, Shi-Wei GU

  理论物理通讯. 1993, 19(1): 27-30.

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  Polaronic states in a parabolic quantum dot are investigated by using the second order Rayleigh-Schrödinger perturbation theory. It is shown that the absolute values of the ground state energy correction and the excited state energy correction as well as the relevant transition energies increase with decreasing the size of the quant um dot. The results also indicate that the polaron effects in small quantum dots are stronger than those in the corresponding bulk materials.
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  High Phonon Frequency Approximation in the Calculation of Phonon Drag Magnetothermopower

  G. QIN, P.N. Butcher, T.M. Fromhold

  理论物理通讯. 1993, 19(1): 31-38.

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  At high magnetic fields and low temperatures the phonon drag magnetothermopower is dominated by phonons with energies much greater than k_BT. This fact is used to develop an approximate formula which can be evaluated in a few percent of the time required by the rigorous result. We show that the predominant contribution to the magnetothermopower comes from the transition process in which both the initial Landau level and the final Landau level have the same quantum number n = n'= n_f where nf distinguishes the level nearest to the Fermi energy. A double summation over n and n'can therefore be neglected. In the temperature range of 1.275 K to 5.005 K, all the HPFA results agree with the experimental data and the rigorous theoretical results qualitatively. At T = 2.495 and 2.937 K, the HPFA results arein fair quantitative accordance with the experimental data and the rigorous theoretical results.
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  Effective Potential Method for Positron Annihilation at Zero Temperature

  Xiao-Wu HUANG, Yi WANG, Xiang-Bin WANG

  理论物理通讯. 1993, 19(1): 39-42.

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  By using the theory of Green's function and the effective potential method, we calculate the total positron annihilation rates for twenty-nine types of chemical elements. Our theoretical results are in agreement with the experimental values.
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  The Superfluidity of the Charged Bosons'System

  Zhong-Yi LU

  理论物理通讯. 1993, 19(1): 43-48.

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  We establish a model of bosons in which a boson carries a charge-|e| and there exists a positive and homogeneous background which makes the system neutral. We show that the superfluidity may emerge in very general conditions for the model in support of some superconductivity theories based on the formation of bosonic bound state of two electrons.
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  The Temperley-Lieb-Jones Algebra and Symmetry Group in Heisenberg Spin Models in One and Two Dimensions

  Shao-Ming FEI, Hong YAN

  理论物理通讯. 1993, 19(1): 49-56.

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  We present a systematic method to construct the spin models of Heisenberg type in higher dimensions with nearesband non-nearest neighbour interactions. These models constructed in this way are of Temperley-Lieb-Jones (TLJ) algebraic structures and SU(2)-invariances. The TLJ algebra is generalized to adjusting the lattice spin models. The Hamiltonians of Heisenberg spin models in one dimension (including second nearest neighbour interactions) and in two-dimensional triangular lattice (with nearest interaction) are constructed explicitly. The hidden symmetries are shown to be the SU(2) group, and the terms in Ilamiltonian for different lattice cells are explicitly shown to be the representations of elements of (TLJ) algebra.
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  symmetries of the Z_n × Z_n Belavin Model

  Rui-Hong YUE, Yi-Xin CHEN

  理论物理通讯. 1993, 19(1): 57-62.

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  It is shown that there exist some symmetries in the Z_n × Z_n Belavin model. These symmetric properties can be used to construct the new exactly solvable statistical model with nontrivial boundary terms.
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  On the Kac-Moody ⊗ Virasoro Algebraic Structures of the Symmetries of Super AKNS Integrable Systems

  Li-Ning ZHANG, Yi-Shen LI

  理论物理通讯. 1993, 19(1): 63-70.

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  AKNS systems, as one of the integrable systems, are supersymmetrized. After the calculation of the corresponding recursion operator, two sets of symmetries are obtained. Their Lie brackets constit u te Kac-Moody ⊗ Virasoro algebra.
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  On the Intermittency in Nuclear Fragmentations

  Yu-Ming ZHENG, Hong-Min LIU, Ben-Hao SA, Zhong-Dao LU, Zhong-Qi WANG, Xiao-Ze ZHANG

  理论物理通讯. 1993, 19(1): 71-74.

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  A simple Monte Carlo simulation and even a partition method can be used to reproduce quite well the power law behavior between the factorial moment and the charge interval of fragment charge distributions from the multifragmentation of ¹⁹⁷Au nucleus bombarding emulsion at～1 GeV/nucleon. This indicates that the above power law seems not to be a unique precursor of the intermittent behavior in nuclear multifragmentations.
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  Three-Body Problem with Two Charged Particles (I) The Neutron Induced Nuclear Reaction

  Lian-Yuan CHU, Zi-Li CHU

  理论物理通讯. 1993, 19(1): 75-84.

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  We present the details of an exact method for the treatment of Coulomb effects in neutron induced three-body n uclear reactions. Based on the three-body in tegral equations, the formalist allows the practical calculation of elastic, inelastic, and breakup processes without an approxima tion of C.M. Coulomb interaction.
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  A Microscopic Calculation of Nucleon-Antinucleon Bound States

  Zuo-Qun CHEN, Jun-Chen SU, Yu-Bing DONG, Shi-Shu WU

  理论物理通讯. 1993, 19(1): 85-96.

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  A microscopic study of nucleon-antinucleon (N N) bound states is achieved starting from the relativistic Pauli-Schrödinger equation for q³q³ bound states. From this equation, a complex off-shell qq one-gluon-exchange potential is derived. Use of this potential and the resonating group method to calculate the NN bound states leads to results which are useful to analyze some of the NN experimental data reported in recent years.
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  The Contribution to Δs and Δg from the Hybrid Components of a proton

  Chao-Hsi CHANG, Chao-Shang HUANG, Jian-Guo HU, Xue-Qian LI

  理论物理通讯. 1993, 19(1): 97-106.

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  The hybrid components of a pro ton can give rise to direct contribution to Δg due to the gluon operator and Δs due to the axial current operator as well. We evaluate such contribution precisely within the framework of the bag model, but the result shows that the contribution is not significant.
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  The Grin Alice Sees Is Not from Cheshire Cat RHIC-a Good Place for Observing Glueballs

  Chong-Shou GAO, Xue-Qian LI, Wei LU

  理论物理通讯. 1993, 19(1): 107-112.

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  In the recent study on the relativistic heavy ion collisions (RHIC), the crucial problem is how one can identify the formation of quark-gluon-plasma (QGP). In this paper, we find that the number of glueballs produced from QGP is sizable and definitely affect the flavor and rapidity distributions of mesons which finally reach detectors. We propose that RllIC would be a good candidate for observing glueballs. We also suggest that the recent K⁺/π⁺ ratio may not indicate the QGP formation.
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  Does Shadowing Relate to Nuclear Radius?

  W. ZHU, X.Y. FU

  理论物理通讯. 1993, 19(1): 113-116.

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  The A-dependence of nuclear shadowing in the partonic shadowing model is analysed. We point out that the nuclear shadowing is related to the average number of shadowed nucleons rather than the nuclear radius.
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  A Supersymmetric Model for 17 KeV Neutrino

  Dong-Sheng DU, Chun LIU

  理论物理通讯. 1993, 19(1): 117-120.

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  A supersymmetric model for accommodating the 17 KeV neutrino is proposed. The rank-two Majorana mass matrix for right-handed neutrinos can be obtained in a natural way. The neutrino spectrum is the same as that in the Glashow's model. The lifetime of the 17 KeV neutrino can satisfy the cosmological constraints.
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  Phenomenological Connection Between Hadronic Wavefunction and Its Radius

  Xin-Heng GU0, Tao HUANG

  理论物理通讯. 1993, 19(1): 121-124.

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  A picture for the hadronic structure is discussed based on previous work^[1]. The radius contributed from the valence Fock-state wavefunction (i.e., qq component) is calculated in ~ the light-cone framework. We propose a concept of the characteristic length λ to represent the contributions of higher Fock states to hadronic radii phenomenologically and calculate its value. Using an equivalence between the "intrinsic" radii of constituent quarks and the radii coming from higher Fock states we put forward a constraint on the hadronic wavefunctions of mesons. It is found that these wavefunctions lead to consistency between theories and experiments for D and B exclusive decays. We also give the radii for K, D and B mesons. The results show that the radius of K meson is in good agreement with experimental data.
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  Remarks on the Quantization of Self-Dual Fields

  Yan-Gang MIAO

  理论物理通讯. 1993, 19(1): 125-128.

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  We investigate the Srivastava's and the Floreanini-Jackiw's formalisms of self-dual fields. By imposing an additional constraint on phase space we overcome the former's non-unitarity at the quantum level and simultaneously translate the former into the latter. Through introducing a parameter to extend the self-duality condition we show that both formalisms guarantee that it is only the self-dual field that exists in a consistent Hamiltonian quantum theory.