1999年, 第32卷, 第4期　
刊出日期：1999-12-15

  

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  Spatiotemporal Chaos Control with Pinning Signals in Distributed Systems

  GAO JiHua, XIAO JingHua, YAO YiGui, HU Gang

  理论物理通讯. 1999, 32(4): 481-488.

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  We suggest a local pinning feedback control for stabilizing periodic pattern in spatially extended systems. Analytical and numerical investigations of this method for a system described by the one-dimensional complex Ginzburg-Landau equation are carried out. We found that it is possible to suppress spatiotemporal chaos by using a few pinning signals in the presence of a large gradient force. Our analytical predictions well coincide with numerical observations.
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  Enhancement of B(E2) Collectivity in the sdg-Interacting Boson Model

  LONG GuiLu, JI HuaYing, ZHU ShengJiang

  理论物理通讯. 1999, 32(4): 489-492.

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  It is pointed out that the difficulty in boson models in explaining the large B(E2) experimental data is not due to the lack of collectivity in boson model wavefunction. This long standing problem of reduction in collectivity of wavefunction in boson models can be solved by choosing an appropriate E2 transition operator in the SU(3) limit of the sdg-interacting boson model. The ratio B(E2, L + 2 → L)/B(E2,2 → 0) can be almost any large number.
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  Sum Rule in a Consistent Relativistic Random-Phase Approximation

  MA ZhongYu

  理论物理通讯. 1999, 32(4): 493-498.

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  A fully consistent relativistic random-phase approximation (RRPA) is studied in the sense that the relativistic mean-field (RMF) wavefunction of nucleus and the particlehole residual interactions in the RRPA are calculated from the same effective Lagrangian. A consistent treatment of RRPA within the RMF approximation, i.e., no sea approximation, has to include also the pairs formed from the Dirac states and occupied Fermi states, which is essential for satisfying the current conservation. The inverse energy-weighted sum rule for the isoscalar giant monopole mode is investigated in the constrained RMF. It is found that the sum rule is fulfilled only in the case where the Dirac state contributions are included.
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  M-Theory Inspired Low Energy Phenomenology

  HUANG ChaoShang, LI TianJun, LIAO Wei, YAN QiShu, ZHU ShuHua

  理论物理通讯. 1999, 32(4): 499-506.

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  In both the scalar quasi-massless SUSY breaking scenario and dilaton-dominant SUSY breaking scenario, we analyze experimental constraints to the parameter space in M theory compactified on S¹/Z₂. The sparticle spectrum and some phenomenological predictions are given.
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  A Study of Brane Solutions in D-Dimensional Coupled Gravity System

  ZHOU Bin, ZHU ChuanJie

  理论物理通讯. 1999, 32(4): 507-514.

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  We use only the equation.of motion for an interacting system of gravity, dilaton and antisymmetric tensor to study the soliton solutions by making use of a Poincaré-invariant ansatz. We show that the system of equations is completely integrable and the solution is unique with appropriate boundary conditions. Some new classes of solutions are also given explicitly.
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  The Optical Properties of (C₅₉N)₂

  WAN XianGang, DONG JinMing, XING DingYu

  理论物理通讯. 1999, 32(4): 515-520.

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  Using the extended Hubbard model and sum-over-state method, we have calculated the linear polarizability α and the third-order nonlinear polarizability γ for (C₅₉N)₂. We find that (C₅₉N)₂ has very big γ value (around esu), and its α and γ values are bigger than those of C₅₉N. In particular, when 1.2 eV≤3ω, (C₅₉N)₂ as much larger γ values than C₅₉N.
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  Time Evolution for Relative Phase of Two Bose-Einstein Condensates

  YI XueXi, SUN ChangPu

  理论物理通讯. 1999, 32(4): 521-524.

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  Considering the collisions between the two condensates and the tunneling effects, we study the time evolution of the relative phase of two Bose-Einstein condensates (BECs). The phase amplitude is given in coherent picture for many cases, which furnishes us a new method to study the interference of two BECs.
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  Approximate Good Quantum Numbers in Cs Stark States

  LI Yong, LI BaiWen

  理论物理通讯. 1999, 32(4): 525-532.

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  Using Cs atom zero-field wavefunctions from a kind of atomic potential model, and the mean value of z-component of spin angular momentum (S_z) in each Stark state, we numerically investigate the approximate good quantum numbers in Cs Stark states. Our results quantitatively confirm the concept that m_t and m_s, can be taken as the approximate good quantum numbers in two cases, except for some Stark states in a few special field points or ranges; however we also find that m_t and m_s, cannot be treated as the approximate good quantum numbers for these special Stark states.
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  Effect of the Aharonov-Bohm Potential on the Optical Polaron Soliton Motion in One-Dimensional Rings

  YU ChaoFan, LUO YiPing

  理论物理通讯. 1999, 32(4): 533-536.

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  The effect of the Aharonov-Bohm potential on the optical polaron solitons is considered by making use of vibration configuration resulting from the energy minimum. Two new polaron solutions with solitary wave form and their relevant properties have been obtained. The results show that the soliton's shape, location, self-trapping energy and effective mass depend on the Aharonov-Bohm dux. At the same time, the bell solitons appear at the polaron energy band, while the kink excitation at the top.
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  Possible Propagating Intrinsic Localized Vibrational Modes for One-Dimensional Klein-Gordon Lattice

  ZHOU GuangHui, YAN JiaRen, TANG Yi

  理论物理通讯. 1999, 32(4): 537-544.

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  A11 possible existed propagating intrinsic localized vibrational modes for the discrete Klein-Gordon lattice are obtained analytically in the whole w(q) space of the system by means of the so-called semidiscrete approximation, with which the carrier wave is treated explicitly while the envelope is described in the continuum approximation. Our investigation shows that, in general, both the pulse-like and kink (antikink) envelope types of the vibrational modes for the system can occur with certain carrier wavenumbers and frequencies in the separated parts of the ω(q) space. And the propagating velocity of the pulse-like modes is either subsonic or nearsonic, abd that of the kink (antikink) modes is either subsonic or supersonic. Our results are similar to or consistent with some results for Klein-Gordon lattice model or other related nonlinear lattice systems by some different methods.
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  Magic Numbers and Ground-State Transitions of Coupled Quantum Dots

  XIE WenFang, CHEN ChuanYu

  理论物理通讯. 1999, 32(4): 545-548.

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  The methods for few-body physics are introduced to extract features of a double dot contained three electrons. We find that the electron correlation in double dot leads to angular momentum magic numbers being distinct from those of a single dot. Discontinuous groundstate transitions induced by an external magnetic field have been predicted. The decisive effect of symmetry has been emphasized.
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  Ergodic Properties and Thermodynamics in Anharmonic Oscillator Systems

  ZHENG ZhiGang

  理论物理通讯. 1999, 32(4): 549-556.

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  Ergodic properties of anharmonic oscillator systems with only a few degrees of freedom are both theoretically and numerically investigated. Statistical mechanics and thermodynamics of ergodic Hamiltonian systems are built. The Henon-Heiles systems with reflecting walls and the diamagnetic Kepler problem are studied
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  A Free-Fermion Type Solution of Quantum Dynamical Yang-Baxter Equation

  JU GuoXing, LUO XuDong, WANG ShiKun, WU Ke

  理论物理通讯. 1999, 32(4): 557-562.

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  The symmetries of the quantum dynamical Yang-Baxter (QDYB) equation without spectral parameters for glz are discussed. The classification of the six-vertex type solu tjons to the QDYB equation without spectral parameters is given and a free-fermion type solution is obtained.
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  Exact Solitary Wave Solutions of Surface Waves in a Convecting Fluids

  LOU SenYue, ZHU YueJin, WANG LieYan

  理论物理通讯. 1999, 32(4): 563-566.

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  In the standard Painlevé analysis, the singular manifold can be extended to many different forms because of its arbitrariness. Using some kinds of standard and nonstandard truncation approaches for the extended singular manifolds to a convecting fluid, we can obtain abundant solitary wave structures.
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  The Collective Excitation Spectra of σ, ω and π Mesons in Nuclear Matter

  LIU LiangGang

  理论物理通讯. 1999, 32(4): 567-574.

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  The recent progress on the study of the collective excitation in relativistic nuclear matter is reviewed. The collective excitation modes are derived by meson propagators in nuclear matter. The mesons we studied are σ, ω, γ and π mesons. For pion, we derived not only the relativistic particle-hole, delta-hole excitations but also antiparticle excitations, suchas particle-antiparticle, antidelta-particle, delta-antiparticle excitations. By calculating the dispersion relation and the spin-isospin-dependent response function, the effects of all these excitation are studied.
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  Zero-Density Phase Transition to Quark-Gluon Plasma and the Relativistic Finite Baryon Volume Effect in Hadronic Matter

  ZHANG XiaoBing, ZHANG QiRen

  理论物理通讯. 1999, 32(4): 575-582.

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  We examine the role of relativistic finite baryon volume effect in the phase transition between hadronic matter and quark-gluon plasma at vanishing baryon density. It is found that the appearance of abnormal state at high temperature may enhance the baryon-antibaryon excitation, which has large influence on the quark-gluon plasma formation. The numerical results show that the occurence of this phase transition depends on how to extrapolate the nucleon-scalar meson coupling constant to the baryonic resonance-scalar meson coupling.
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  Preliminary Test of Calculation Results of Two-Body Correlation Transport Theory for Heavy-Ion Collision

  LIU JianYe, M. Di Toro, LIU Hang, ZUO Wei

  理论物理通讯. 1999, 32(4): 583-592.

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  In order to test the two-body correlation transport theory proposed early (J.Y. Liu, et al., Nucl. Phys. A604 (1996) 341), we make a detailed comparison of the preliminary numerical results of it with those of quantum molecular dpamical model because which has been extensively and successfully used for describing the dynamical process of heavy-ion collisions. The comparisons show that all behaviors of quantities studied for different incident conditions of the heavy-ion collisions are very similar for two theories. This implies that the two-body. correlation transport theory is promising for the description of heavy-ion collision dynamics.
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  Mixing of Pseudo-Goldstone Bosons and Effects on HERA High-Q² Events

  XIAO ZhenJun, ZHANG JinYu

  理论物理通讯. 1999, 32(4): 593-600.

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  We study the mixing of pseudo-Goldstone bosons predicted by technicolor theory and the effects on HERA high-Q² events. We find that: (a) there eyist two F = 0 scalar leptoquarks P₃′ with m(P₃′) = 200 GeV and P₃⁰ with m(₃⁰) =225 GeV for β₁ = β₂ = 0.4; (b) the P₃′ and P₃⁰ can contribute the required cross section to account for the excesses of NC and CC high-Q² events; (c) the coexistence of P₃′ and P₃⁰ may be responsible for the splitting of averaged mass of the H1 and ZEUS high-Q² neutral current events.
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  Thermal QCD

  ZHAO WanYun

  理论物理通讯. 1999, 32(4): 601-606.

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  By the methbd of the gauge field theory at finite temperature, the static thermodynamic properties in quark-gluon plasma are studied in detail. According to the renormalization group equation, an analytic expression of the running coupling constant g(T, p) with the temperature T is obtained.
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  Residue Entropy of Overscreen Multi-Channel Kondo Model: a Study of Large K Expansion

  SHAW Ming, JIN Duo

  理论物理通讯. 1999, 32(4): 607-610.

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  We study the residue entropy of overscreen multi-channel Kondo model by means of perturbathe renormalization group. In this field theory framework one must use pseudofermion representation for local spin operator, and the constraint of pseudofermion must be treated properly. We treat the constraint by a method developed recently. In this method the partition function of the Kondo model is separated into proper weighted partition functions of subsystems. We study the overscreen multi-channel Kondo model through M-subsystem. F'rom calculating the residue entropy of M-subsystem, we obtain the residue entropy of original system which agrees with the result of conformal field theory.
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  Differential Forms of Completeness Relation in Two-Mode <ξ|- <η| Representations

  FAN HongYi, LIU NaiLe

  理论物理通讯. 1999, 32(4): 611-614.

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  On the basis of the common eigenvectors <ξ| and <η|, which respectively are eigenvectors of two particles'relative position and total momentum as well as center-of-mass coordinate and relative momentum, we find that there exist differential forms of completeness relation. The applications of the new completeness relation are pointed out. Throughout our discussion the technique of differentiation within an ordered product of operators is fully employed.
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  On q-Commutator in the Case q^s+l = 1

  YANG YaPing, FENG WeiGuo, WU Xiang

  理论物理通讯. 1999, 32(4): 615-616.

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  In this letter, the representations of q-commutator in the case q^s+l = 1 and the eigenstates of annihilation operator have been discussed.
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  SU(3)_L × U(l)_X Model and N-Particle as Dark Matter Particle

  CHEN FengZhi

  理论物理通讯. 1999, 32(4): 617-620.

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  We proposed an SU(3)_L × U(l)_X gauge model for the electroweak interactions. In the model each lepton family contains two neutral particles. We show that the new neutral lepton (N-particle) can play the role of dark matter particle.