1991年, 第16卷, 第4期　
刊出日期：1991-12-15

  

• 全选
  |

• Select
  The Test and Comparison of Three Equations of State for Solids

  Li-Rong CHEN, Qing-Hu CHEN

  理论物理通讯. 1991, 16(4): 385-392.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  Vinet equation, Couchman-Reynolds equation and Birch equation are tested and compared by using the data of compressibility for 29 kinds of metals and 9 alkali halide compounds. The rerrults show that the Vinet equation is the best one among three equations, and its universality is very prominent.
• Select
  SU(2) Lattice Gauge Theory Formulation of the (2+1)-Dimensional Antiferromagnetic Heisenberg Model

  Wen-Zhou LI, C. I. TAN

  理论物理通讯. 1991, 16(4): 393-400.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The equivalence of 2+1 antiferromagnetic Heisenberg model and the SU(2) Kogut Susskind lattice gauge theory is recapitulated and the naive Euclidean lattice action of the threedimensional an tiferromagnetic Heisen berg model is derived. The three-dimensional lattice gauge fermion theory is formulated to give the consistent lattice gauge theory of antiferromagnetic Heisenberg model. In continu um limit the two copies of two flavor fermions are resulted, which give the negative results of the microscopic derivation of the Chern-Simons terms. The Chern-Simons terms, the gauge invariant problem of effective action and the '%hiralityn are discussed.
• Select
  Study of Double-Layer Heisenberg Antiferromagnetic Systems

  Shi-Min CUI

  理论物理通讯. 1991, 16(4): 401-406.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  A double-layer square lattice Heisen berg an tiferromagnetic system is studied by using Green's function technique. It is shown that the sublattice magnetization increases with the increase of the antiferromagnetic interlayer exchange coupling J_I for small J_I , while it turne to decrease for large J_I. In contrast to the conventional spin-wave calculations, there always exists a finite zero-temperature staggered magnetisation. The transition from the antiferromagnetic phase to disordered phase is also discussed.
• Select
  The Temperature Dependence of the Effective Mass of a Two-Dimensional Polaron

  Wai-Sang LI, Shi-Wei GU

  理论物理通讯. 1991, 16(4): 407-414.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The properties of a two-dimensional polaron in the polar crystal are discussed by means of a model which takes account of the atomicity of the lattice. The lattice vibration and the interaction between the electron and the lattice displacement are treated by second quantization-method. The self-trapped energy and the effective mass of the two-dimensional polaron are derived.
• Select
  Exact Stationary Solution of Fokker-Planck Equation and Generalized Potential for Non-Equilibrium Systems Without Detailed Balance

  Cun-Zheng NING, Gang HU

  理论物理通讯. 1991, 16(4): 415-420.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  An exact analogy is approached between systems in thermal equilibrium and those far from equilibrium which can be the cases without detailed balance. The analogy is based on the requirement that a given drift in the Fokker-Planck equation can be decomposed into two parts, one of which is divergence-free and the other can be derived from a potential which is invariant along the direction of the first part. If the conditions are fulfilled the Fokker-Planck equation changes in to a standard Poisson equation. The relations of this requirement to other conditions are diecussed. As a concrete example, the stationary Fokker-Planck equation for optical bistability is solved by using"this method.
• Select
  An Example of the Absence of the Non-Standard Solutions of QYBE

  Mo-Lin GE, Guo-Chen YU, Kang XUE, Xi-Fu WANG

  理论物理通讯. 1991, 16(4): 421-426.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  In this paper by employing the weight conservation and the diagrammatic techniques we solved the quantum Yang-Baxter equations. It is shown that the solutions associated with the 6 of SU(3) are standard alone.
• Select
  The Braid Group Representation of IRF Model

  Hong-Kang ZHAO

  理论物理通讯. 1991, 16(4): 427-432.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The braid group representations (BGRs) corresponding to IRF model are discussed by solving the spectral-independent Yang-Baxter Equation in the cases q = 2 and 3. The BGRB obtained here are constant matrices.
• Select
  Boson Representations of Subalgebra Chain for Quantum Algebra (C_l)_q with q a Root of Unity

  Chang-Pu SUN, Xu-Feng LIU, Mo-Lin GE

  理论物理通讯. 1991, 16(4): 433-438.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The method of q-deformed boson realization is extended to the caee that q is a root of unity. By using thb method, many irreducible and indecomposable representations of each su balgebra in a su balgebra chain of the quantum universal enveloping algebra (quan tum algebra) (C_l)_q are obtained on the q-deformed Fock space and its quotient space. AB an example, the representations of (C₃)_q are constructed in explicit forms. Besides, by embedding (A₁)_q = (C_l)_q, into the subalgebra chain, a new realisation of (A₁)_q and its representations are obtained.
• Select
  The Estimation of the Difference Between d(d, n)³He and d(d, p)T Cross Sections in the Cold Fusion

  Jing-Shang ZHANG

  理论物理通讯. 1991, 16(4): 439-442.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The difference between two reaction cross sections of d(d, p)T and d(d, n)³He has been estimated in the cold fusion. It is caused by the different potential wall transmission and the angular distribution due to the structure.of deuterons. The rough estimation indicates that the branching ratio b about two orders of magnitude.
• Select
  The Nonperturbative QCD Correction to the Quark-Quark Pot ential

  Peng-Nian SHEN, Xue-Qian LI, Xin-Heng GUO

  理论物理通讯. 1991, 16(4): 443-450.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  A potential describing the interaction between quarks is obtained by considering not only perturbative effects of QCD, but also the nonperturbative contributions via (qq) and condensates. In this potential, a linear confinement type term and a new r³ term can be automatically obtained. A tendency to flatten the potential at large distance is observed and it L consistent with the phenomenologically introduced potential which giva a better fit for nucleon spectrum.
• Select
  Higher Genus Solutions for the N × N Matrix Model

  Zhan-Ning HU, Hua WEI

  理论物理通讯. 1991, 16(4): 451-456.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  For the N × N Hermitian matrix model with a potential of quartic anharmonic term, a general expression of vacuum energy E_H for arbitrary genus H is presented, and higher genus solutions E₃, E₄ and E₅ are evaluated explicitly.
• Select
  Calculation of Phase Diagram of Lattice SU(3) Mixed Model

  Yong XU, Xi-Te ZHENG

  理论物理通讯. 1991, 16(4): 457-462.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The variational-cumulant expansion method has been extended to SU(3) mixed-action lattice gauge theories. By using the method, the phase diagrams of SU(3) mixed model are obtained in four and five dimensions. The results are in good agreement with the Monte Carlo results. The comparison with results of the mean field method and the mean plaquette method is abo given.
• Select
  Weak Transition Form Factors Among Heavy to Light and Heavy to Heavy Baryons

  Y. L. WU

  理论物理通讯. 1991, 16(4): 463-470.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The matrix elements among heavy to light and heavy to heavy baryons are evaluated by using the method developed by the author in previous paper. It is found from this method that the form factors can be written down in a simple constructing rule by introducing a set of useful spin tensors. The method also allows us to obtain absolutely normalized form factors at the maximum momentum transfer for Q → Q' or q induced weak transitions among baryon states such as 1/2⁺ → 1/2⁺, 3/2⁺, 1/2^-, 3/2^- etc.
• Select
  Comment on the Calculations for Some Bound State Annihilation and creation

  Chao-Hsi CHANG, Yu-Qi CHEN, Yu-Ping KUANG, Yu-Ping KUANG

  理论物理通讯. 1991, 16(4): 471-476.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  For a process, involving annihilation or creation of a (quark-antiquark pair) bound state with two or more vertices i.e. at least there is one propagator in the corresponding Feynman diagram(s), we point out that the bound state effects in such a process need to be treated more precisely if requiring a more accurate estimate, due to the propagator(s) involved, rather than to make so crude approximation, to attribute the effects so simple as a factor proportional to the wavefunction at origin of the bound state into the amplitude of the process finally.
• Select
  Solution of the Schwinger-Dyson Equation Involving the Gluon condensate Kernel

  Xin-Heng GUO, Tao HUANG

  理论物理通讯. 1991, 16(4): 477-484.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The form of the quantum chromodynamic Schwinger-Dyson (SD) equation modified by the nonperturbative kernel associated with the gluon condensate is obtained. It is shown that the eolution for the renormalisation group invariant quark condensate from the SD equation is in agreement with that obtained from the consistent equation for quark condensate when the leading behavior of the dynamical quark mass is concerned^[1]. It is also found that the gluon condensate kernel makes the critical coupling constant above which the chiral symmetry breaks smaller and increases the value of the quark condensate.
• Select
  Pseudospin Wave State in One-Dimensional Half-Filled Hubbard Model

  Zhi SONG, Hong SHEN

  理论物理通讯. 1991, 16(4): 485-488.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  All the eigenfunctione with spin S = (M - 1)/2 of one-dimeneional half-filled Hubbard model are obtained by ueing a eimple method (M is the number of the sites). These eigenfunctions depend on U, t, and the momentum k. It ie shown that the eigenetates we obtained can describe varioue kinde of pseudospin waves with wave vector k and these pseudoepin wave etates are accompanied with a charge transferring. This is in agreement with the exact diagonalisation results for emall eitee ring.
• Select
  Strong Electromagnetic Standing Waves in a Ferromagnetic System

  Ying WU, Xiao-Xue YANG

  理论物理通讯. 1991, 16(4): 489-492.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  Strong nonlinear circularly polarixed elec tromagnetic standing waves modulated in the direction of the dc magnetic field in a ferromagnetic syetem are investigated. Four distinct classes of standing wave solutions are shown to exist.
• Select
  Ward Identities for W_∞ Conformal Field Theories on a Torus

  Chao-Shang HUANG, Liang-Xin LI, De-Hai ZHANG

  理论物理通讯. 1991, 16(4): 493-496.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  From the PRS algebra, Ward identities are derived for W_∞ algebra on a torus in the character sense. We find.an n-point amplitude with energy-momentum tensor insertion or with any other spin field insertion related by the Ward identity to that with all other spin field insertions and ib derivatives with respect to the modular parameters. Ward identities are also derived in conventional sense. Similarly, these Ward identities are infinitely correlative.
• Select
  Heteroclinic Orbit on the KdV-Burgers Equation and Fisher Equation

  Shi-Kuo LIU, Shi-Da LIU

  理论物理通讯. 1991, 16(4): 497-500.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The heteroclinic orbit between the saddle and node points or the saddle and focus points on the KdV-Burgers equation and Fisher equation is analyzed. The corresponding travelling wave lrolutions are obtained.
• Select
  A Note on Two-Nucleon Mechanism in the Neutrinoless Double Beta, Decay

  Hui-Fang WU, Hong-Qiu SONG

  理论物理通讯. 1991, 16(4): 501-504.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  One-pion exchange correction to the conventional two-nucleon mechanism in the nuclear neutrinoless double beta (Ovββ) decay Q discussed. A numerical calculation is carried out for ⁴⁸Ca Ovββ decay. The result8 indicate that thie correction is absolutely negligible, compared with the conventional two-nucleon mechanism.
• Select
  ChiraESymmetry Breaking in (1+l)-Dimensional Lattice Gauge Theories

  Xiang-Qian LUO

  理论物理通讯. 1991, 16(4): 505-508.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The (1+1)-dimensional Hamiltonian lattice gauge theories and the Mcuum structure with fermions are studied analytically by using a unitary transformation and the variational method. The matching of the φφ operators in the continuum and on the lattice is discussed. The chiral symmetry is shown to be broken spontaneously. The effect of species doubling is also analyzed. Satisfactory scaling behavior for the chiral order parameter and coincidence with the continuum predictions are obtained.
• Select
  CKM Angles, B_d⁰ - B_d⁰ Mixing and the Mass of the Top Quark

  Jia-Fu LIU, Ling-De WAN, Gong-Ru LU

  理论物理通讯. 1991, 16(4): 509-512.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The ranges of the sines and cosines of the CKM angles are analyzed, the B_d⁰ - B_d⁰ mixing is reviewed, and the maas of the top quark ie calculated. The results show that m_t > 76 GeV, the effect of the uncertainty of S₂ on mt is very important, and S₂ must be very small.