1991年, 第15卷, 第3期　
刊出日期：1991-04-30

  

• 全选
  |

• Select
  Magnetic Excitation at the Surface of a Substitutionally Disordered Antiferrornagnet

  HONG Qiang, LIN Tsunghan

  理论物理通讯. 1991, 15(3): 257-262.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The magnetic excitation at the auiface of a substitutionally disordered antiferromagnet is etudied by using the Bethe-lattice method. Some numerical resulte are presented.
• Select
  Real Time Feynman Rules for Thermodynamic Green's Functions of an Electron Gas

  XU Honghua, TSAI Chienhua

  理论物理通讯. 1991, 15(3): 263-270.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The Feynman rules are established for thermodynamic Green's functions of an electron gas by means of the closed-time-path Green's function formalism which avoids infinite sums over discrete frequencies and analytical continuations. The thermodynamic potential of the system is 0btained.h a closed form in the random phase approximation which reduces correctly at 0° K to the RPA correlation energy of the ground state theory.
• Select
  An Inverse Scattering Transformation for the Modified Nonlinear Schrijdinger Equation

  CHEN Zongyun

  理论物理通讯. 1991, 15(3): 271-276.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  A new Lax pair of the modified nonlinear Schrödinger equation is introduced in terme of the variable of the Fourier transform λ. The Lax pair has no usual symmetries between 12 and 21 elements and avoids the factor λ^1/2. The basic equation of inverse scattering transformation is deduced in the Zakharov-Shabat form as well as in the Marchenko form.
• Select
  Cyclotron Resonance of an Interface Magnetopolaron at Finite Temperatures

  WEI Baohua, GU Shiwei

  理论物理通讯. 1991, 15(3): 277-284.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  Taking into account the interaction of an electron with both bulk longitudinal-optical (LO) and interface-optical (IO) phonons, the cyclotron resonance of an interface magnetopolaron at finite temperatures is investigated by using the generalized Larsen perturbation-theory method. It is shown that the absorption and emission resonance must be considered at the same time at finite temperatures. The results also show the important role played by the electron-IO phonon interaction. For the GaAa/GaSb structure, splitting of the cyclotron resonance spectrum and temperature dependence of the threefold splitting cyclotron resonance mass of the magnetopolaron in the resonant magnetic field region are studied.
• Select
  Calculation of Binding Energies of the Ground and Excited States of a Donor in GaAs-A1_xGa_l-xAs Step Quantum Wells

  GU Benyuan, HUO Chongru

  理论物理通讯. 1991, 15(3): 285-302.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  In this paper we present for the first time completely analytical variational expressions for calculating the binding energies of the low-lying bound states of a hydrogenic donor in a quantum well (QW). These expressions can be used for the problem of the binding energy of an impurity in a general manner, e.g. for calculating the binding energies of a donor associated with subband states of any order in the QW with any arbitrary potential profile. 70 demonstrate the utilization of these expressions we have theoretically studied the binding energies for the ground and a few low-lying excited etates of a hydrogenic donor in a stepped quantam well (SQW). The variations of the binding energies for these donor etates with impurity positions are investigated for different heights of the step potential. The numerical calculation results show that the binding-energy curves in the SQW, in contrast to the case of the flat quantum wells (FQW's), exhibit a non-symmetrical structure relative to the center of the QW and depend on the sub-barrier potential. The peak position in the binding energy curves shifts away from the region occupied by the sub-barrier as increasing sub-barrier height. The maximum in the binding energies increases as the step potential increaaes. These effects can be interpreted by referring to the variation of the electron probability-density distribution and of the lowest subband in the SQW. The shape of the binding-energy curves related to the 2po-like state is different from the other states. It is associated with the particular feature of the wave function of the 2po state in the QW.
• Select
  Bethe-Salpeter Equation With Self- Energy Graphs Ⅱ——Spectral Analysis for Scalar BS Equation

  CHENG Geng

  理论物理通讯. 1991, 15(3): 303-308.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  Bethe-Salpeter equation in ladder approximation with self-energy graphs is diecussed for the model problem of two dftinguiahable equal-mass scalar particles exchanging a single maesive ecalar boson. The spectral features are analyzed.
• Select
  The Finite Temperature Effects on the Coleman Phase Transition in Double Sine-Gordon Model

  LOU Senyue

  理论物理通讯. 1991, 15(3): 309-318.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  By means of the finite temperature Gaussian effective potential (FTGEP) method, the (1+1) and (2+1) dimensional quantum double sine-Gordon (DsG) field theories are studied nonperturbatively for finite temperature. The explicitly FTGEP is obtained for both (1+1) and (2+1) dimensional DaG models. The temperature-dependent Coleman phase transition conditions obtained by us would reduce to the known results g_cr² when T→0. The alternative explanation of the Coleman phase transition at finite temperature is that for fixed coupling constantg² there is a critical temperature T_cr (whose value depends ong²) such that the theory becomes unstable when the temperature of the system exceeds the critical value T_cr.
• Select
  Proof of Chiral Symmetry Breaking and Persistent Mass Condition in Vector- Like Gauge Theory

  ZHOU Bangrong

  理论物理通讯. 1991, 15(3): 319-330.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  We give the details of rigorous proof of some mass inequalitiee in a vector-like gauge theory based on any simple group G. These mass inequalitiee lead to the conclusions that in auch a theory the chiral symmetries associated with all G representations of quarks must be spontaneously broken, and the persistent mass condition ie justified for any composite particles when the vacuum angle is zero or massless quarks exist.
• Select
  More Nonlocal Conserved Currents in Chiral Sigma Models

  CHAO Liu, LU Jingfa

  理论物理通讯. 1991, 15(3): 331-338.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The infinite many nonlocal conserved currents are given for the principal chiral model. Wess-Zuminc-Witten chiral model and the supersymmetric chiral model with respect to the new hidden symmetry transformatione. It is shown that these conserved currents are related to the classical r-matrix and thus decompose into many families. The approach used here provides a systematic method to derive the Casimir operators for the infinite dimensional Lie algebras in its nonunitary and nonhighest weight representations.
• Select
  Geometric Quantization of Anyon Systems

  YU Yue, ZHU Zhongyuan

  理论物理通讯. 1991, 15(3): 339-346.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  Geometric quantization of multiparticle systems in 2 dimensions is studied. The interpretation of the global geometry to the phase factors describing the quantum statistics of the systems is presented.
• Select
  Universal, Solution of Oppenheimer-Volkov Equatiops for Strange Stellar System Based on the MIT Bag Model

  WANG Chengshing, WANG Wenyan

  理论物理通讯. 1991, 15(3): 347-352.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The universal solution of Oppenheimer-Volkov equations with strange quark matter equation of state of the MIT bag model is calculated in a reduced form which is independent of the MIT constant B. The lower limit of the observational pulse period of pulsars (0.69 ma) is predicted by the MIT bag constant B=(146 MeV)⁴ which ia fitted to the hadronic spectrum, while the observed lower limit of pulse period of pulaara (1.56 ms) gives an astrophysical restriction on the lower limit of the MIT bag constant as B>(97 MeV)⁴.
• Select
  The Post-Newtonian Effects of the Rotation of the Central Body on the Motion of the Celestial Body in Three Gravitational Theories

  LI Linsen

  理论物理通讯. 1991, 15(3): 353-358.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The post-Newtonian effects of the rotation of the central body on the variation of celestial orbital elements are studied according to the post-Newtonian metric theory. The variation of celestial orbital elements caused by the rotation of the central body in three gravitational theories of Einstein, Brans-Dicke and Nordtvedt is obtained by using the method of general perturbation. The resulting effects are the periodic variation of inclination, eccentricity and mean anomaly; the periodic and secular variation of longitudes of periastron and ascending node and mean longitudes of epoch, but the semimajor axis remains unperturbed (no variation). In addition, the obtained theoretical results are applied to the calculation of the post-Newtonian effect of the rotation of the sun on the variation of the orbital elements of planets in solar system. The numerical results are given in nble 1. Finally, the obtained results are discussed and compared with other theories.
• Select
  The Cluster-Cluster Growth of the Small Meta1-Particle

  DENG Zhaojing, LIU Cunye

  理论物理通讯. 1991, 15(3): 359-364.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  A detailed discussion on experiment reported in Ref. [1] is presented. By decomposing the real gold-ultrafine-particle system into three subsystems S¹, S² and S³, we find that the number of clusters especially large clusters for system S³ increases rapidly in CCA process, and the subsystem S¹, in which the average particle size,is smaller than that in subsystem S², is still more stable than S². This result is consistent with the consequence of "Atomistic Method".
• Select
  The Modified Nonlinear Schriidinger Equation:Darboux Transformation and Projection Matrices

  XIAO Yi

  理论物理通讯. 1991, 15(3): 365-368.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The Darboux transformation and Bkklund transformation for the modified nonlinear Schrödinger equation are derived by a recently presented method and a new solution is obtained by using them.
• Select
  A New Approach to Elucidating Quantum-Mechanical SO(3) Rotation

  FAN Hongyi, LIU Fangxin

  理论物理通讯. 1991, 15(3): 369-372.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  In this letter, the logarithm of the three-dimensional Euclidean rotation matrix R is calculated, and its physical meaning is discussed. The new rotation operator identity D(R)≡ƒd³|Rr ><(r| = exp{a_i^†(lnR)_ija_j} (where a_i^†(a_i) are creation (annihilation) operators of a three-dimensional harmonic oscillator), which is deduced by the technique of integration within ordered product, motivates us to discuss In R. The present work, together with the previous one^[2], provides a new approach to elucidating quantum-mechanical rotation.
• Select
  A New q-Deformed Boson Realization of the Quantum Algebra C_q(l) and Its Representations

  LIU Xufeng, SUN Changpu

  理论物理通讯. 1991, 15(3): 373-376.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  A new q-deformed boson realization of the quantum algebra C_q(l) is given and some of its finite dimensional representations are explicitly presented when q is a root of unity.
• Select
  On Solutions to the q-Deformed Oscillator Systems and the q-Oscillator Algebra H_q (4)

  YAN Hong

  理论物理通讯. 1991, 15(3): 377-382.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  Discussions upon the q-oscillator systems and the q-oscillator algebra H_q(4) are provided,and the case of |q| = 1 ia detailed. A remarkable connection between SH_q(2) and H_q(4) is indicated and investigated. The single q-oscillator system t solved and shown to be analogous to the parafermion (PF), with the specific case analogous to the third order PF discussed in detail. The properties of the representations and a finite chain model are exploited.
• Select
  A Simple Calculation of the Central Charge for XXZ Heisenberg Chain

  XU Bowei

  理论物理通讯. 1991, 15(3): 383-384.

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The XXZ Heisenberg chain ie equivalent to the Thirring model, from which we can. calculate the central charge. The result coincides with that by other meane.