30 January 1985, Volume 4 Issue 1

    

• Select all
  |

General
• Select
  MULTIPHONON NOPRADIATIVE TRANSITION OF RARE-EARTH IONS

  MA Dong-ping, XU Yi-sun

  Communications in Theoretical Physics. 1985, 4(1): 1-11.

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Based on the general theory^[2-4], the formula of RE³⁺ multiphonon nonradiative transition probability is derived by adopting simplified approximations involving single-frequency model. Satisfactory agreement is obtained through the comparison of theory and experiment. The principal differences between the present paper and relevant literatures as well as the validity of simplified approximation are discussed.
• Select
  ON DIFFICULTIES ASSOCIATED WITH THE SECOND OUANTUPI RULE IN THE PHYSICAL REPRESENTATION

  FU Hong

  Communications in Theoretical Physics. 1985, 4(1): 13-19.

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Two difficulties of the second quantum rule in the star-unitary transformation theory are discussed. First,by using perturbation theory at order four, we show that the energy superoperator p_ℜ can not be diagonalized for a class of Hamiltonians. Second,if the transformation Λ has the property Λ·≠Ⅱ which is a result of the second quantum rule for some models, we point out that the microcanonical equilibrium will not lead to the minimum H-quantity.
• Select
  DYfNAMICAL THEORY OF CLASSICAL SURFACE PLASMAS II

  LU De-xin, Kenneth I. Golden

  Communications in Theoretical Physics. 1985, 4(1): 21-37.

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  The first and second equations of the.Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy have been solved for the 20 electron gas. Adopting a procedure parallel to 3D Coste calculation for 2D situation, the authors obtain a new expression for the dynamical polarizability α(k,ω,γ)a lid over the entire range of (k,ω). In the long wavelength limit, the dumamical superposition structure emerges as remarkable ?? and ?a clusters. Low frequency response i s formulated. Both the collisional and correlational corrections have been, explicitly calculated. We also discuss the structure of the low frequency excitation modes and ultimately determine the collisional contribution and the leading term of the correlational contribution to the darnping.
• Select
  THE PHASE TRANSITION FROM THE "ROTATION" TO VIBRATION SPECTRA IN THE LIPKIN SU(2) MODEL

  XU Gong-ou, LI Fu-li

  Communications in Theoretical Physics. 1985, 4(1): 39-49.

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  The collective monopole excitation spectra of the Lipkin SU(2) model aresolveaexactly in the truncated monopole phonon representation and also approximately in the continuous variable representation. The transition from the "rotation" to vibration spectra for lowly-lying exclted states with the increase of the particle number in the upper level and the disappearance of the monopole "deformation" with the increase of the excitation energy are exhibited. The origin of these phase transitions is explained and the shape transition of real nuclei with the number of valence nucleons i s briefly discussed.
• Select
  HOW TO DETERMINE THE NUCLEAR MATRIX ELEMENT IN 2β-Decay?-A DISCUSSION OF PCAC, 2β-DECAY AND DOUBLE-CHARGE EXCHANGE REACTION OF PIONS ON NUCLEI

  CHING Cheng-rui, HO Tso-hsiu

  Communications in Theoretical Physics. 1985, 4(1): 51-56.

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  It is shown that by applying PCAC, the 2β-decay process can be directly related to double-charge-exchange reaction. Therefore, by studying double-charge-exchange reactions one is able to determine the nuclear matrix element of the relevant 2β-decay experimentally. A preliminary analysis has indicated that if the experimental data of forward-angle cross section on Ca⁴⁰ with pion beam at 164 Mev^[9] are used and extrapolated to Ca⁴⁸, then the squared nuclear matrix element thus determined is smaller than that calculated for Ca⁴⁰→Ti⁴⁸+2e^-+2v^[11] by 10⁵～10⁶.
• Select
  HARMONIC EMSSIONS FROM LASER-PRODUCED PLASMAS

  YU Wei, XU Zhi-zhan

  Communications in Theoretical Physics. 1985, 4(1): 57-66.

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Haimonic veneration as a result of resonant absorption in laser-roduced plasmas is investigated by considering the steepened plasma density gradients in the vicinity of the critical density. We obtained an efficiency of the second harmonic emission which is in better agreement with experiments than previous theories. The present calculation has also been extended to including the efficiency of the third harmonic emission, the results obtained indicate that at sufficiently high laser intensities, the third harmonic emission generated by the resonant absorption can also be observed.
• Select
  THE B-S EQUATION OF THE COMPLEX SCALAR FIELD

  LI Hong-cai, CHING Cheng-rui, RUAN Tu-nan

  Communications in Theoretical Physics. 1985, 4(1): 67-76.

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  The renormalization properties of the self-interacting complex scalar field are discussed, its Dyson equation is the presented,the B-S equation of the identical- bosons and relation between the irreducible kernel and the vertex function are derived.
• Select
  THE SIMPLIFIED EQUATION FOR RELATIVISTIC NEUTRON'S MOTION IN EXTERNAL MAGNETIC FIELD

  ZHANG Yong-de, WU Min, ZHANG Tai-yong, YAN Mu-lin, RVAN Tu-nan

  Communications in Theoretical Physics. 1985, 4(1): 77-90.

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  In this paper the Dirac's equation for the neutron in external magnetic fields is given. After decoupling into two equations of the simple spinors, the simplified equations are obtained by some reasonable approximations. The corresponding second order non-relativistic approximation, Green's function and single particle,spectrum are derived. It is shown that, apart from easy solution, the precision of the simplified equation is sufficiently high, its applications are universal.
• Select
  ANOf}ALIES OF ARBITRARY GAUGE GROUP AND ITS REDUCTION GROUP, EINSTEIN AND LORENTZ ANOMALIES

  Kuang-chao CHOU, Han-ying GUO, Ke WU

  Communications in Theoretical Physics. 1985, 4(1): 91-101.

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Based upon the properties of the characteristic classes and their Chern-Simons secondary characteristic classes. the "Abelian" anomalies in M²ⁿ⁺²,the Euler-Heisenberq effective actions in M²ⁿ⁺¹, as well as the non-Abelian anomalies in M²ⁿ for arbitrary gauge gzoup and its reduction subgroup have been investigated thoroughly and the application to the gravitational anomalies is made. It is shown that the "Ahelian" anomalies of such groups are equal to each other, their Eu1er-Xeisenberg actions are also closely related to each, other,and their non-Abelian anomalies are also equivalent if their common generating functional can be taken as a counter-term.For the gravitational anomalies we present the common genera- ting functional for both non-Abelian Einstein and Lorentz anomalies M⁴ⁿ⁺² and show the relationship between them.
• Select
  FURTHER DISCUSSIONS OF THE EXACT GAUGE COUPLING β FUNCTION IN SUPERSYMMETRIC YANG-MLLLS THEORIES

  Fang-xiao Dong, Tung-sheng TU, Pei-you XUE, Xian-jian ZHOU

  Communications in Theoretical Physics. 1985, 4(1): 103-112.

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  The exact gauge coupling β function in the N-extended pure supersymmetric Yang-Mi11s (SYM) theories is extended to arbitraru gauge group and the exact β function in N=2 SyM theories with N=2 matter multiplets is obtained. Its vanishing in the latter cases is explicitly checked at two-loop level.
• Select
  CHERN-SIMONS TYPE CHARACTERISTIC CLASSES

  GUO Han-ying, WU Ke, WANG Shi-kun

  Communications in Theoretical Physics. 1985, 4(1): 113-122.

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  It is shown that one can generalize the concept of well-known Chern-Simons secondary characteristic classes to introducing a sequence of new characteristic classes named the Chern-Simons type characteristic classes. One of the important properties is given by a theorem which can be interpreted as that the exterior differential of a ktb Chern-Simons type characteristic class is exactly equal to the coboundary of the cochain of the k-1st Chern-Simons type characteristic classes.
• Select
  ON THE TWO DIMENSIONAL NON-LINEAR σ MODEL WITH WESS-ZUMINO TERM II QUANTUM THEORY

  CHOU Kuang-chao, DAI Yuan-ben

  Communications in Theoretical Physics. 1985, 4(1): 123-127.

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  The canonical quantization is carried out for the two dimensional non-Linear a model with wess-2umino term. It is shown that the currents in this model satisfy a Kac-Moody algebra for arbitrary values of the coupling constant.
• Select
  THE SYMMETRY BREAKING IN LIVING SYSTEMS Ⅱ. MULECULAR CHIRALITY AfdD MORPHOLOGICAL CHIRALITY

  DING Da-fu, XU Jing-hua

  Communications in Theoretical Physics. 1985, 4(1): 129-144.

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  This article is a further study on the chiral symmetry breaking in living systems.Even when the instability of racemic thermodynamic branch and parity violating force exist simultaneously, the preferred synthesis of handed molecules can not be guaranteed.The coupling between a chiral field and macroscopic mode of a morphologically chiral symmetry in molecular sense. The specific conditions which ensure the molecular sense.The specific condition which ensure the molecular chiral symmetry breaking are elabrated.
• Select
  ANOMALIES, COHOMOLOGY AND ChIERN-SIMONS COCHAINS

  GUO Han-ying, HOU Bo-yu, WANG Shi-kun, WU Ke

  Communications in Theoretical Physics. 1985, 4(1): 145-155.

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  We present a concept of the gauge transformations, establish the homomorphic relation between this conomology group and the Chern-Simons type. charaateric class sequence,and analyse their applacatons to the non-Abelian anomaly, the gauge invariant Wess-Zumino effective action and the Schwinger term etc.we show that the present approaches.includes faddeev's song's and zumino'sapproaches.