Table of contents

20 October 1996, Volume 5 Issue 10 Previous issue    Next issue

ATOMIC AND MOLECULAR PHYSICS

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EFFECT OF CONFIGURATION INTERACTION ON EXCITATION AUTOIONIZATION CROSS SECTIONS HU WEI (胡畏), CHEN CHONG-YANG (陈重阳), FANG DU-FEI (方渡飞), WANG YAN-SEN (王炎森), YANG FU-JIA (杨福家), TENG HUA-GUO (滕华国) Acta Physica Sinica (Overseas Edition), 1996, 5 (10):  721-727.  DOI: 10.1088/1004-423X/5/10/001 Abstract ( 1416 )   PDF (202KB) ( 476 )   The effect of configuration interaction (CI) on the theoretical calculation of autoionization cross section for Li-like ions are studied in detail by employing the distorted wave Born exchange approximation. We consider the 1s22s→1s2s2p and 1s22s→1s2s3p transitions for Cs3+ and Al10+ ions. These two transitions account for the largest excitation autoionization cross section. It is found that the CI has a significant effect on the calculated results. The effect becomes larger with increasing atomic number.

CLASSICAL AREAS OF PHENOMENOLOGY

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AZOBENZENE POLYMER FILMS FOR OPTICAL STORAGE AND HIGH-ORDER DIFFRACTION (I)——POLY[4'-BIS(N, N-OXYETHYLENE) IMINO-4-NITROAZOBENZENE SUCCINYL] FILM WEI XIONG (魏雄), YAN XING-ZHONG (颜星中), LIN WEI-ZHU (林位株), MO DANG (莫党), LIANG ZHAO-XI (梁兆熙) Acta Physica Sinica (Overseas Edition), 1996, 5 (10):  728-736.  DOI: 10.1088/1004-423X/5/10/002 Abstract ( 1321 )   PDF (241KB) ( 374 )   The properties of phase conjugated (PC) beam and stable optical storage in an azobenzene polymer film were studied by degenerate four-wave mixing. With low-intensity incident waves (peak value of the pulses of the order of W/cm2), the PC beam as well ms diffraction beams were observed and then disappeared after turning off one of the three incident Beams. When the peak intensities of the incidenl beams reached the order of 10 W/cm2, the PC beam did not disappear but decreased to some extent after turning off the writing beams. As the peak intensities of incident beams increased to the order of l03 W/cm2, diffraction up to 4th-order was observed. When all of the three incident waves were turned on, three groups of high-order forward and backward diffraction heams were observed. Turning off two of the three incident beams, the diffraction beams of the other incident beams did not decrease obviously, i.e., stable optical storage was realized. After the experiments, brilliant hologram spot was observed and could be maintained over 120 days without obvious change.

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QUANTUM PHASE AND DYNAMICAL PROPERTIES OF LIGHT IN THE JAYNES-CUMMINGS MODEL VIA PHASE COUPLING FAN AN-FU (范安辅) Acta Physica Sinica (Overseas Edition), 1996, 5 (10):  737-749.  DOI: 10.1088/1004-423X/5/10/003 Abstract ( 1271 )   PDF (311KB) ( 434 )   It is pointed out here that quantum phase properties, as well as dynamical prop-erties, of light exhibit a sensitivity to the relative phase between the atomic dipole and light when the atom is prepared in a coherent superposition of its states in the two-level Jaynes-Cummings model interacting with a coherent state of light. The existence of the coherent-trapping of light is demonstrated by looking not only at the variance of the light phase about the coherent state value, and the number-phase uncertainty relation, but also at the factorization of the electric-field operator, and the photon-number distribution. We find also the factorization expression of the com-pound state of the atom-field system. We show once more that the phase properties of light based on the phase operator formalism of Pegg-Barnett and the coherence properties of light based on the coherence theory of Glauber are complementary in description of the optical quantum coherence.

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SECOND HARMONIC GENERATION WITH PHOTON NUMBER SQUEEZED LIGHT AS INPUT WU MEI-JUAN (吴美娟), WU LING-AN (吴令安), LI SHI-QUN (李师群) Acta Physica Sinica (Overseas Edition), 1996, 5 (10):  750-755.  DOI: 10.1088/1004-423X/5/10/004 Abstract ( 1388 )   PDF (142KB) ( 366 )   We investigate the quantum statistics of the fields produced in second harmonic generation when photon number squeezed light ia used as input. It is found that the squeezed properties of the pump beam can be transferred to a certain extent to the second harmonic beam. The normalized photon fluctuations, or Fano factors, of the fundamental and second harmonic output fields are derived for various values of the interaction parameters.

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MAXIMAL EMITTED POWER OF HYPERRADIANCE FROM PERTURBED JOSEPHSON SYSTEMS HAI WEN-HUA (海文华), XIAO YI (肖奕) Acta Physica Sinica (Overseas Edition), 1996, 5 (10):  756-763.  DOI: 10.1088/1004-423X/5/10/005 Abstract ( 1241 )   PDF (213KB) ( 370 )   Consider two magnetically coupled and perturbed long Josephson junctions which operate in synchronized modes. Under first order approximation, the soliton solution of the system is derived by using a new perturbation technique. It is shown that the perturbing parameters limit the emitted power from the system, and the physically relevant coupling parameter leads to the increase of power. The formula of maximal emitted power is given for a particular power input. The results solve some important problems left over by previous analysis.

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SUPERPOSITION OF COHERENT STATES IN KERR MEDIUM WU JIN-WEI (吴锦伟), GUO GUANG-CAN (郭光灿) Acta Physica Sinica (Overseas Edition), 1996, 5 (10):  764-768.  DOI: 10.1088/1004-423X/5/10/006 Abstract ( 1370 )   PDF (88KB) ( 428 )   The evolution of the input coherent state in the Kerr medium is studied. Upon the derivation we know that the output state at time t which corresponds to a rational number is Schr$\ddot{\rm o}$dinger's cat state. Using Fourier integral of the evolution operator, we obtain the integral expression of the output state at time t which corresponds to an irrational number. It is a kind of one-dimensional continuous superposition of coherent states, not an ordinary Schr$\ddot{\rm o}$dinger's cat state.

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GROUP-VELOCITY DISPERSION IN CHIRPED-PULSE AMPLIFIER SHEN YU-ZHEN (沈宇震), XING QI-RONG (邢岐荣), SHI JI-YING (石季英), WANG QING-YUE (王清月) Acta Physica Sinica (Overseas Edition), 1996, 5 (10):  769-780.  DOI: 10.1088/1004-423X/5/10/007 Abstract ( 1245 )   PDF (372KB) ( 397 )   By using the pulse propagation equation in the nonlinear dispersive medium, the effects of second- and third-order group-velocity dispersion on pulse evolution in the stretching, amplification and compressing are studied when chirped pulse am-plification is applied to the pulses of a width <30fs, and the optimum dispersion-compensated conditions among the stretcher, amplifier and compressor are deter-mined. From the standpoint of dispersion compensation and control and the com-pressor adjustment, it is proposed that low-groove-density gratings (≤800 line/mm) are the better choices for stretching and compressing the pulses of a width <30fs in chirped-pulse amplification. It is also shown that, with a proper adjustment of the compressor incident angle and grating separation, an exact null in both second- and third-order dispersions can be achieved without any additional dispersion- compensated elements.

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

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MAGNETIZATION CHARACTERISTICS OF YBaCuO BULK MATERIAL FABRICATED BY THE SEEDING TECHNIQUE CAI CHUAN-BING (蔡传兵), FU YAO-XIAN (傅耀先), SUN YUE (孙越), GONG SHANG-MING (龚尚敏) Acta Physica Sinica (Overseas Edition), 1996, 5 (10):  781-789.  DOI: 10.1088/1004-423X/5/10/008 Abstract ( 1269 )   PDF (267KB) ( 375 )   YBaCuO (YBCO) bulk materials with large superconductive domains were fab-ricated using a small SmBa2Cu3Ox grain as the seed for growth, The capacities of strong flux pinning and well grain linking in the material have been shown in the investigations on magnetization loop end ac susceptibility. The strong flux pinning made it possible for the large YBCO bulk to capture a great dea. l of flux and keep the residual magnetism stable. The residual field intensity Hrem was shown to have a maximum of 0.125 T after the 0.5 T NdFeB magnetizing field was moved away. We did not find much decline of Hrem in a short time. The magnetized YBCO bulk pro-duced repulsive force upon another YBCO bulk as the permanent magnet did. We measured and calculated the force between two YBCO bulks. The theoretical result was in agreement with the experimental one by and large.