Table of contents

15 August 1999, Volume 8 Issue 8 Previous issue    Next issue

GENERAL

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BOUND STATES OF THE KLEIN-GORDON EQUATION WITH VECTOR AND SCALAR WOOD-SAXON POTENTIALS HOU CHUN-FENG (侯春风), ZHOU ZHONG-XIANG (周忠祥), LI YAN (李焱) Acta Physica Sinica (Overseas Edition), 1999, 8 (8):  561-564.  DOI: 10.1088/1004-423X/8/8/001 Abstract ( 1254 )   PDF (69KB) ( 651 )   The S-wave Klein-Gordon equation with vector and scalar Wood-saxon potentials is solved and the energy levels are given through an equation.

NUCLEAR PHYSICS

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CLUSTER EFFECTS IN DEUTERIUM CLUSTER ION IMPLANTATION ON SOLIDS WANG TIE-SHAN (王铁山), KENTARO OCHIAI, KATHOHIKO MARUTA, AKITO TAKAHASHI Acta Physica Sinica (Overseas Edition), 1999, 8 (8):  565-570.  DOI: 10.1088/1004-423X/8/8/002 Abstract ( 1277 )   PDF (168KB) ( 406 )   Atomic and nuclear cluster effects of (D+3) were studied by alternative implantation of deuterium cluster ion beam and isolated deuteron (D+) beam on metal targets. The beam energy was adjusted from 10keV/d to 100keV/d in experiment. The atomic cluster effect was shown by the enhancement of X-ray emission induced by cluster deuterion. The average ratio of X-ray intensity induced by each cluster deuteron to that induced by each isolated deuteron is about 2.6 in the experimental energy region. The nuclear cluster effect is shown by the difference of D-D fusion rates induced by two kinds of deuterons under the same experimental conditions. The ratio of the D-D fusion rates induced by the two kinds of deuterons is energy dependent.

CLASSICAL AREAS OF PHENOMENOLOGY

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PHOTON STATISTICS OF THE MICROMASER WITH ULTRA COLD Λ-TYPE THREE-LEVEL ATOMS ZHANG　ZHI－MING (张智明), LI　XIAN－FENG (李先锋), ZHOU　SHI－KANG (周士康) Acta Physica Sinica (Overseas Edition), 1999, 8 (8):  571-576.  DOI: 10.1088/1004-423X/8/8/003 Abstract ( 1203 )   PDF (145KB) ( 420 )   We have established the master equation for the micromaser with the ultra-cold $\varLambda$-type three-level atoms and studied the photon statistics of the micromaser field. We find that as the atoms become colder,the change of the mean photon-number and the normalized standerd deviation become more regular, and their resonance peaks become sharper. For zero-temperature cavity,there are some regins in which the photon statistics are sub-Poissonian.With the increase of the cavity temperature,both the mean photon-number and the normalized standard deviation increase. When the cavity temperature is high enough, the sub-Poissonian property may disappear.

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NONCLASSICAL PROPERTIES OF PHOTON-ADDED PAIR COHERENT STATES LU HONG (路洪), GUO GUANG-CAN (郭光灿) Acta Physica Sinica (Overseas Edition), 1999, 8 (8):  577-582.  DOI: 10.1088/1004-423X/8/8/004 Abstract ( 1419 )   PDF (117KB) ( 605 )   The two-mode photon-added state defined by |$\zeta$,q;m>=a+mb+m|$\zeta$,q> up to a normalization constant is introduced, where |$\zeta$,q> is a pair coherent state and m an integer. It is shown that the fields in such a state have remarkable quantum features such as sub-Poissonian statistics, violations of Cauch-Schwarz inequalities, correlations in the number fluctuations and squeezing. We examine the influence of photon-adding on the properties of pair coherent of cavity quantum electrodynamics.

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POPULATION TRAPPING IN MULTI-LEVEL SYSTEM VIA QUANTUM INTERFERENCE DENG LE (邓乐), WANG WEI-SHENG (王蔚生), SUN ZHEN-RONG (孙真荣), DING LIANG-EN (丁良恩), WANG ZU-GENG (王祖赓) Acta Physica Sinica (Overseas Edition), 1999, 8 (8):  583-589.  DOI: 10.1088/1004-423X/8/8/005 Abstract ( 1192 )   PDF (190KB) ( 336 )   Population trapping via quantum interference in a multi-level system driven by a coherent field is investigated. The influences of the alignment of the transition dipole moments and the energy-level separation of the upper levels are taken into account. Detailed trapping population profiles under the different conditions are given. The research result is helpful for simplifying the theoretical model and selection rational energy level system.

PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

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A DIRECT PERTURBATION THEORY OF THE NONLINEAR SCHR$\ddot{\rm O}$DINGER EQUATION WITH CORRECTIONS CHEN SHI-RONG (陈世荣), CHEN ZHI-DE (陈芝得), YUAN XIAN-ZHANG (袁先漳), HUANG NIAN-NING (黄念宁) Acta Physica Sinica (Overseas Edition), 1999, 8 (8):  590-597.  DOI: 10.1088/1004-423X/8/8/006 Abstract ( 1322 )   PDF (205KB) ( 389 )   An exact direct perturbation theory of nonlinear Schrodinger equation with corrections is developed under the condition that the initial value of the perturbed solution is equal to the value of an exact multisoliton solution at a particular time. After showing the squared Jost functions are the eigenfunctions of the linearized operator with a vanishing eigenvalue,suitable definitions of adjoint functions and inner product are introduced. Orthogonal relations are derived and the expansion of the unity in terms of the squared Jost functions is naturally implied. The completeness of the squared Jost functions is shown by the generalized Marchenko equation. As an example,the evolution of a Raman loss compensated soliton in an optical fiber is treated.

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

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THE PROPERTIES OF THE GROUND STATE OF THE NONADIABATICALLY COUPLED ELECTRON-PHONON SYSTEMS WITH CORRELATED DISPLACEMENT AND SQUEEZING PANG XIAO-FENG (庞小峰), LI PING (李萍) Acta Physica Sinica (Overseas Edition), 1999, 8 (8):  598-606.  DOI: 10.1088/1004-423X/8/8/007 Abstract ( 1072 )   PDF (269KB) ( 352 )   Eeffcts of the nonadiabatic phonon fluctuations on the ground state of coupled onedimensional electron-phonon systems with high and low electron-densities were investigated by a new ansatz including correlated interaction of the displacement and squeezing. The correlated effect resulted in noticeable reduction of ground state energy of the systems, and obvious increases of binding energy of the polarons occurred. Thus,the stabilities of the polaron and of the systems were significantly enhanced,exactly steady ground state of the Holstein model, then,was obtained by the new ansatz for the coupled electron-phonon systems. In general,the new ansatz were found to be very relevant for the strong coupling and large squeezing cases in nonadiabatically coupled electron-photon systems.

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GROUP-CHAIN SCHEME ANALYSIS OF THE ENERGY LEVELS AND MAGNETIC PROPERTIES OF Nd3+ IN LiYF4 CRYSTAL CHEN XUE-YUAN (陈学元), LUO ZUN-DU (罗遵度) Acta Physica Sinica (Overseas Edition), 1999, 8 (8):  607-612.  DOI: 10.1088/1004-423X/8/8/008 Abstract ( 1055 )   PDF (177KB) ( 365 )   Based on the analysis of group-chain scheme, the crystal-field-level fitting of Nd3+: LiYF4 has been carried out, in which the Nd3+ inos occupy positions with site symmetry S4. The RMS deviation of energy-level fitting is 12.8cm-1. Using the obtained wave functions, g-factors of the fround state are calculated,which are g∥=2.067 and g⊥=2.631, in good agreement with the experimental values(g∥=1.978 and g⊥=2.554). The method proposed turns out to be effective in the study of spectral properties of localized centres in laser crystals.

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LATTICE MODEL OF STRIPE DOMAIN STRUCTURE IN FERROMAGNETIC ULTRATHIN FILMS HU LIANG-BIN (胡梁宾), LI HAI-JIN (厉海金), TAO RUI-BAO (陶瑞宝) Acta Physica Sinica (Overseas Edition), 1999, 8 (8):  613-623.  DOI: 10.1088/1004-423X/8/8/009 Abstract ( 1139 )   PDF (331KB) ( 388 )   A lattice model is proposed to describe the stripe domain sructure in a magnetic ultrathin film that consists of only a few or tens of monolayers and has a perpendicular anisotropy.The dipolar energies of the perpendicular and in-plane uniform magnetic states and the stripe domain structures in a magnetic ultrathin film are calculated separately using Ewald's lattice summation method. The thickness dependence of the stripe domain structure is investigated, and the stability of the stripe dimain structure is discussed. The results show that for magnetic ultrathin films the stripe dimain structure may have sensitive dependence on their thickness.

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EFFECT OF DOPANT ON THE UNIFORMITY OF InAs SELF-ORGANIZED QUANTUM DOTS WANG HAI-LONG (王海龙), ZHU HAI-JUN (朱海军), FENG SONG-LIN (封松林), NING DONG (宁东), WANG HUI (汪辉), WANG XIAO-DONG (王晓东), JIANG DE-SHENG (江德生) Acta Physica Sinica (Overseas Edition), 1999, 8 (8):  624-628.  DOI: 10.1088/1004-423X/8/8/010 Abstract ( 1229 )   PDF (149KB) ( 410 )   Low-temperature photoluminescence studies have been performed on Si-doped and Bedoped self-organized InAs/GaAs quantum dot(QD) samples to investigate the effect of doping. When Si or Be is doped into the sample,a remarkable decrease in line-width is observed. We relate this phenomenon to a model that takes the Si or Be atoms as the nucleation centers for the formation of QDs. When Si or Be is doped, more smalll uniform quantum dots are formed. The result will be of significance for the application of self-organized InAs quantum dots in semiconductor devices.