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Entropy product measure for multipartite pure states

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Science china(physics,Mechanics & Astronomy) 2006年第5期49卷 606-615页

作者： CAO Wancang1,2, LIU Dan2, PAN Feng3.& LONG Guilu2,4 1. department of physics, Chifeng College, Chifeng 024001, china 2. Key Laboratory for Quantum Information and Measurements, department of physics, Tsinghua University, Beijing 100084, china 3. department of physics, Liaoning Normal University, Dalian 116029, china 4. Key Laboratory for Atomic and Molecular Nano-Sciences, Tsinghua University, Beijing 100084, china correspondence should be addressed to Long Guilu department of physics Chifeng College Chifeng China Key Laboratory for Quantum Information and Measurements Department of Physics Tsinghua University Beijing China department of physics Liaoning Normal University Dalian China Key Laboratory for Atomic and Molecular Nano-Sciences Tsinghua University Beijing China

An entanglement measure for multipartite pure states is formulated using the product of the von Neumann entropy of the reduced density matrices of the constituents. Based on this new measure, all possible ways of the maximal entanglement of the triqubit pure states are studied in detail and all types of the maximal entanglement have been compared with the result of ‘the average entropy’. The new measure can be used to calculate the degree of entanglement, and an improvement is given in the area near the zero entropy.

关键词： multipartite pure state von Neumann entropy entanglement measure

Spectral anomalies and spectral switches of partially coherent and polychromatic light diffracted at an aperture

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Science china(physics,Mechanics & Astronomy) 2004年第1期47卷 24-35页

作者： Lü Baida1, 3.& PAN Liuzhan1, 2 1. Institute of Laser physics and Chemistry, Sichuan University, Chengdu 610064, china 2. department of physics, Luoyang Normal College, Luoyang 471022, china 3. State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan 43.074, china correspondence should be addressed to L Baida (email: badalu@***) Received July 10, 2003 Institute of Laser physics and Chemistry Sichuan University Chengdu China State Key Laboratory of Laser Technology Huazhong University of Science and Technology Wuhan China department of physics Luoyang Normal College Luoyang China

Based on the propagation theory of partially coherent light in the space-frequency domain, the anomalous spectral behavior and spectral switches in the far field of partially coherent and polychromatic light diffracted at an aperture are studied. It is shown that, as compared with spatially fully coherent and polychromatic light whose spectral anomalies are induced only by aperture diffraction, the spectral anomalies and spectral switches of partially coherent and polychromatic light depend on the aperture diffraction, spatial correlationβ and bandwidth of the original spectrum. Detailed numerical calculations are made to illustrate the behavior of spectral switches of partially coherent and polychromatic light, and the results for spatially fully coherent and polychromatic light are treated as a special case ofβ=1 and included in our theory.

关键词： spectral anomaly spectral switch partially coherent and polychromatic light far field aperture diffraction

Approaches to improving critical current density of YBCO superconducting thick films deposited by electrophoresis

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Science china(physics,Mechanics & Astronomy) 2004年第2期47卷 165-172页

作者： ZHU Yabin1,2, ZHOU Yueliang2, LIU Zhen2, WANG Shufang2, CHEN zhenghao2, L?Huibin2, YANG Guozhen2, XIAO Ling3. REN Hongtao3. JIAO Yulei3.& zheng Minghui3.1. department of {3., College of Science, Beijing Jiaotong University, Beijing 100044, china 2. Laboratory of Optical {3., Institute of {3. and Center for Condensed Matter {3., Chinese Academy of Sciences, Beijing 100080, china 3. General Research Institute for Nonferrous Metals, Beijing 100088, china correspondence should be addressed to Zhu Yabin (email: ybzhu@***) department of physics College of Science Beijing Jiaotong University Beijing China Laboratory of Optical physics Institute of physics and Center for Condensed Matter physics Chinese Academy of Sciences Beijing China General Research Institute for Nonferrous Metals Beijing China

Fabrication of YBCO superconducting thick films by electrophoresis has been widely reported. However, the value of critical current density (J c) is far from what the practical application requires. The superconducting thick films are obtained using top-seeded melt growth method with different proportional Y2BaCuO5 (Y211) addition. High-pressure oxygen has been used in the annealing process to improve the uniformity of the oxygen content in the superconducting thick films. When 40mol% Y211 powder is added to the YBa2Cu3.7–5 (Y123. powder,J c for the superconducting thick film by approaches described above reaches 7.008×103.A/cm2 (77 K, 0 T), which is greater than the value ever reported.

关键词： YBCO thick films, electrophoretic deposition, melt-textured.

Investigation of True Ni^(2+)-Halide Distances in Alkali Halide Lattices

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Journal of Materials Science & Technology 1994年第2期10卷 154-156页

作者： Xuanrong MA(department of physics, Ningxia University, Yinchuan, 750021, china)Maolu DU(Institute of Solid State physics, Sichuan Normal University, Chengdu, 610066, china)(To whom correspondence should be addressed) Ningxia Univ Yinchuan China

Using the μKα model of Ni2+-6X- cluster, the true distances between impurity Ni2+ cation and halide anion in alkali halide lattices are estimated from the optical spectra data. The results suggest that the true impurity cation- ligand anion distances are close to the sum of ionic radii of the impurity cation and ligand anion but not the cation - anion distance of the perfect lattices in the case of that the ionic radius of host cation is more larger than that of impurity cation

关键词： True Cl Br Investigation of True Ni Halide Distances in Alkali Halide Lattices

Fuzzy cluster analysis of the provenance of ancient Yaozhou porcelain body

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Chinese Science Bulletin 2003年第1期48卷 27-30页

作者： LI Guoxia1, ZHAO Weijuan1, LI Rongwu2, XIE Jianzhong1, FENG Songlin3. FAN Dongyu3. ZHANG Ying3. CAI Zhifang3. ZHUO Zhenxi4 & GAO zhengyao1 1. Faculty of Physical Engineering, zhengzhou University, zhengzhou 450052, {3. 2. department of physics, Beijing Normal University, Beijing 100875, {3. 3. High Energy physics Institute, the Chinese Academy of Sciences, Beijing 100080, {3. 4. Archaeology Research Institute, Shanxi Province, Xian 710000, {3. correspondence should be addressed to Li Guoxia (e-mail: Liguoxia@ ***) Faculty of Physical Engineering Zhengzhou University Zhengzhou 450052 China department of physics Beijing Normal University Beijing 100875 China High Energy physics Institute Chinese Academy of Sciences Beijing 100080 China Archaeology Research Institute Shanxi Province Xi'an 710000 China

The technique of neutron activation analysis (NAA) has been employed to measure the content of 29 kinds of elements in the sample of Yaozhou porcelain bodies. Then a fuzzy cluster analysis has been conducted to the NAA data and a diagram of the dynamic fuzzy cluster analysis has been achieved. The results indicate that the batch of ancient Yaozhou porcelain bodies, which were of different overglaze color and were produced by different kilns during a period of over 800 years from the Tang Dynasty (618—907 A.D.) to the Yuan Dynasty (1271—13.8 A.D.), has shared a stable and concentrated raw material source. Provenances of por-celain bodies from different times, though having their spe-cific independence, enjoy a close relationship and are not far from one another. Provenances of porcelain bodies made during the Tang Dynasty and the Five Dynasties (907—960 A.D.) are found to be closer to one another, while those of the Song (960—1279 A.D.) and the Jin Dynasty (1115—123. A.D.) are comparatively concentrated in certain areas and are dif-ferent from those of the Tang Dynasty. Both the tri-colored glazed pottery made in Yaozhou kilns during the Tang Dy-nasty and the Yaozhou porcelain bodies of the Tang period are from the same provenance.

关键词：古代姚州瓷胎窑址粘土矿原料来源中子活化分布模糊聚类分析

Giant magneto-impedance and low-frequency magneto-resistance effect in NiFeB coated composite wires

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Chinese Science Bulletin 2004年第10期49卷 1002-1005页

作者： YUAN Wangzhi WANG Xinzheng ZHAO Zhenjie RUAN Jianzhong LI Xiaodong YANG Xielong department of physics, East {3. Normal University, Shanghai 200062,{3. correspondence should be addressed to Zhao Zhenjie department of physics East China Normal University Shanghai 200062 China

Composite wires of 100 μm insulated CuBewire plated with a layer of NiFeB were produced by elec-troless-deposition, and their magnetic properties were stud-led. The results showed that a good magneto-impedance (MI)effect can be obtained at relatively low frequency. The largestMI ratio (△Z/Z)max obtained is 250% at 500 kHz. Mag-neto-resistance effect was also observed at low frequency,with the (△R/R)max observed to be -8.5% at 540 Hz and 3..7% at 10 kHz. Results are discussed, and the equivalent resistance and inductance as the result of the NiFeB layer are taken into account.

关键词：巨磁阻抗无电沉积涡流电流损耗合成导线低频电机电阻

Three types of maximally entangled states for a two-particle system

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Science china(physics,Mechanics & Astronomy) 2004年第1期47卷 36-41页

作者： RUAN Manqi, XU Gang & ZENG Jinyan department of physics, Tsinghua University, Beijing 100084, china department of physics, Peking University, Beijing 100871, china correspondence should be addressed to Zeng Jinyan (email: jyzeng@***) Received June 16, 2003 department of physics Tsinghua University Beijing China department of physics Peking University Beijing China

For a two-particle (spin 1/2) system, three fundamental forms of complete sets of commuting observables (CSCO) composed of two-body operatorsσ 1α σ 2α are given. The corresponding simultaneous eigenstates constitute three types of maximally entangled states, one of which is the well known Bell basis. This paper discusses the possible pairs of spin observables whose simultaneous measurement outcomes are definitely correlated in probabilistic fashion.

关键词： spin entangled state, complete set of commuting observables, two-body operator.

Effect of excess Y_2O_3.addition on the physical properties of melt processed YBCO bulks

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Science china(physics,Mechanics & Astronomy) 2004年第1期47卷 17-23页

作者： YANG Wanmin1,2,3. ZHOU Lian2, FENG Yong2, ZHANG Pingxiang2, WU Minzhi3.& W. GAWALEK3.1. department of physics, Shaanxi Normal University, Xi抋n 710062, china 2. Northwest Institute for Nonferrous Metal Research. Xi抋n 710016, china 3. Institute fur Physikalische Hochtechnologie e.V(IPHT), Jena, Germany correspondence should be addressed to Yang Wanmin (email: wm-yang@***) Received June 27, 2003 department of physics Shaanxi Normal University Xi’an China Northwest Institute for Nonferrous Metal Research Xi’an China Institute fur Physikalische Hochtechnologie e.V (IPHT) Jena Germany

The YBCO superconductors with Y2O3.addition were prepared by a modified melt textured process and the effects of excess Y2O3.addition on the physical properties of melt textured YBCO have been investigated. It is found that the melt temperature of YBCO samples decreases drastically with the increasing Y2O3. and the maximum levitation forces are drastically different for samples with different Y2O3.addition. It is also found that the optimal Y2O3.addition to YBCO is about 10wt%. Considering the microstructure and the starting composition, the results are well discussed and interpreted.

关键词： YBCO superconductor, melt growth, Y2O3 addition, levitation force.

Time-division phase modulated single-photon interference in a Sagnac interferometer

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Chinese Science Bulletin 2003年第16期48卷 1704-1708页

作者： WU Guang, ZHOU Chunyuan & ZENG Heping Key Laboratory of Optical and Magnetic Resonance Spectroscopy and department of physics, East china Normal University, Shanghai 200062, china correspondence should be addressed to Zeng Heping (e-mail: hpzeng @***) Key Laboratory of Optical and Magnetic Resonance Spectroscopy anddepartment of physics East China Normal University Shanghai China

We introduce a stable, long-distance single- photon Sagnac interferometer, which has a balanced con-figuration to efficiently compensate phase drift caused by change of the fiber-optic path. By using time-division phase modulation, single-photon interference was realized at 1550 nm in a 5-km-long as well as 27-km-long Sagnac fiber loops, with a fringe visibility higher than 90% and long-term sta-bility. The stable performance of the single-photon interfer-ence indicated that the time-division phase-modulated Sag- nac interferometer might readily lead to practical applica-tions in single-photon routing and quantum cryptography.

关键词：单光子干涉干涉仪基本结构相位补偿时分相位调制稳定性量子密码