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Pairwise entanglement and local polarization of Heisenberg model

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Science china(physics,Mechanics & Astronomy) 2008年第10期51卷 1515-1522页

作者： XI XiaoQiang1,2, ZHANG Tao3, YUE RuiHong3,4 & LIU WuMing2 1 Department of Applied Mathematics and physics, Xi’an institute of Post and Telecommunications, Xi’an 710061, china 2 beijing National Laboratory for Condensed Matter physics, institute of physics, chinese academy of sciences, beijing 100080, china 3 institute of Modern physics, Northwest University, Xi’an 710069, china 4 Department of physics, Ningbo University, Ningbo 315211, china Department of Applied Mathematics and physics Xi’an Institute of Post and Telecommunications Xi’an China beijing National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing China institute of Modern physics Northwest University Xi’an China Department of physics Ningbo University Ningbo China

The characteristics of pairwise entanglement and local polarization (LP) are dis-cussed by studying the ground state (states) of the Heisenberg XX model. The re-sults show that: the ground state (states) is (are) composed of the micro states with the minimal polarization (0 for even qubit and 1/2 for odd qubit); LP and the prob-ability of the micro state have an intimate relation, i.e. the stronger the LP, the smaller the probability, and the same LP corresponds to the same probability; the pairwise entanglement of the ground state is the biggest in all eigenvectors. It is found that the pairwise entanglement is decreased by the state degeneracy and the system size. The concurrence approaches a fixed value of about 0.3412 (for odd-qubit chain) or 0.3491 (for even-qubit chain) if the qubit number is large enough.

关键词： Heisenberg XX model local polarization pairwise entanglement

New Dispersed Phase of Electrorheological Fluids:TiO_2 Coating Graphite Particles

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Journal of Materials Science & Technology 2000年第5期16卷 529-530页

作者： Sujuan XU+ and Biao WANG (Harbin institute of Technology, Harbin 150001, china) Shouqiang MEN and Kunquan LU (institute of physics, chinese academy of sciences, beijing 100080, china) Harbin institute of Technology Harbin 150001 China institute of physics Chinese Academy of Sciences Beijing 100080 China

We have prepared novel coated particles, with a conductor graphite core and a dielectric TiO2 coating, as the dispersed phase of electrorheological fluids. One order of magnitude enhancement in the shear stress is obtained by using such composite particles, when it is compared with that of TiO2 particles. The experimental results show a way to get excellent ER system.

关键词： New Dispersed Phase of Electrorheological Fluids Graphite TiO

Adjoint method for the optimum planning of industrial pollutant sources

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Science china Earth sciences 2005年第8期48卷 1270-1279页

作者： LIU Feng1,2, HU Fei2 & ZHU Jiang2 1. College of Environmental sciences, Peking University, beijing 100871, china 2. LAPC, institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china College of Environmental sciences Peking University Beijing China LAPC Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

The optimum planning of industrial pollutant sources, which optimizes the economic object without violating environmental constraints, is an important and hard task to be conquered. In this paper, an adjoint method is developed to solve the problem. The penalty function is in-troduced to deal with the environmental inequality constraints, and Lagrange function is con-structed to derive the adjoint equation and the gradient of the object function. In this means, the gradient of the object function can be calculated by solving the adjoint equation, and the infor-mation from the gradient is used to make the object function descend and approach to an optimal solution after some iterations. A two-dimensional, simplified model is used for numerical experi-ments. The theoretical derivations are verified by the results of the experiments. Furthermore, the adjoint method is shown to be of excellent convergence and efficiency, which is adaptive to the fast development of air quality numerical models and super computers.

关键词： optimum planning, industrial pollutant sources, adjoint equation, penalty function, gradient.

High resistance modulation by the electric field based on La_(0.9)Sr_(0.1)MnO_3/SrTiO_3/Si structure

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Science china(physics,Mechanics & Astronomy) 2009年第9期52卷 1299-1301页

作者： YANG Fang, HE Meng, WEN Juan, JIN KuiJuan, LU HuiBin & YANG GuoZhen beijing National Laboratory for Condensed Matter physics, institute of physics, chinese academy of sciences, beijing 100190, china beijing National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing China

A field-effect configuration based on La0.9Sr0.1MnO3/SrTiO3/Si structure is fabricated on Si substrate by laser molecular-beam epitaxy. The resistance modulation by electric field of the La0.9Sr0.1MnO3/SrTiO3/Si structure is investigated in detail. An evident resistance modulation effect is observed at 80 K. The channel resistance modulation by field effect reaches 1.4×107% and 2.6×106% when VDS are -2 and -6.5 V, respectively. The ON/OFF ratio of approximately 4000 is obtained. The present results are worthy of further investigations for potential applications of resistance modulation by electrostatic field in the heterostructures consisting of perovskite oxides and Si.

关键词： field effect perovskite oxide thin films resistance modulation

Numerical simulation of Meiyu front and the diagnosis of moist vorticity vector

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Progress in Natural Science:Materials International 2007年第11期17卷 1341-1347页

作者： Ping Fan1,2 and Luo Zhexian2(1. institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china 2. Nanjing University of Information sciences & Technology, Nanjing 210044, china) institute of Atmospheric physics Chinese Acad. of Sci. Beijing 100029 China Nanjing University of Information sciences and Technology Nanjing 210044 China

Moist vorticity vector is introduced to study the development and evolution of mesoscale convective vortex (MCV) in the Meiyu front precipitation with the Advanced Regional Predication System (ARPS). In this study, the heavy rainfall is simulated to investigate the genesis, development and dissipation of middle scale convective vortex, which occurred from 0000 UTC 3 July to 1200 UTC 5 July over the Jianghuai River valley. Moist vorticity vector (MVV) has zonal, radial and vertical components in its 3D spatial distribution. The simulation shows that the vertical component of moist vorticity vector well demonstrates the spatial distribution characteristics of middle scale convective vortex, especially in the process of Meiyu front precipitation. Diagnosis upon zonal, radial averaged and mass-integrated quantities of MVV shows that its vertical component and the surface precipitating ratio are in phase with a correlation coefficient of 0.68, indicating that the vertical component of MVV is closely associated with the Meiyu front precipitation. In addition, the tendency of the vertical component of MVV is mainly determined by the interaction between the vorticity and the zonal and radial gradient of condensational or depositional heating.

关键词： moist vorticity vector mesoscale convective vortex Meiyu front precipitation

Brownian ratchets driven by flashing noise strength

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chinese Science Bulletin 1999年第21期44卷 1956-1961页

作者： ZHAO Tongjun, ZHAN Yong, ZHUO Yizhong and WU XizhenDepartment of Applied Mathematics and physics , Hebei University of Technology , Tianjin 300130, china china institute of Atomic Energy, beijing 102413, china institute of theoretical physics, chinese academy of sciences , beijing 100080, china Corresponding author Dept. of Appl. Math. and physics Hebei University of Technology Tianjin 300130 China china institute of Atomic Energy Beijing 102413 China institute of theoretical physics Chinese Academy of Sciences Beijing 100080 China

The stochastic transport driven by flashing multi-noise sources in a ratchet is studied. The stationary current versus the noise strength and the colored noise correlated time T is obtained . At a fixed flip rate and strength of the colored noises, the novel phenomenon of the current reversal occurs as T reaches a certain value. More than one reversal point exists when

关键词： flashing force ratchet current reversal Langevian equation.

Strengthening of the boreal winter Hadley circulation and its connection with ENSO

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Progress in Natural Science:Materials International 2007年第11期17卷 1327-1333页

作者： Ma Jie1,2 and Li Jianping2(1. College of Atmospheric sciences, Lanzhou University, Lanzhou 730000, china 2. LASG, institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china) College of Atmospheric sciences Lanzhou University Lanzhou 730000 China LASG Institute of Atmospheric Physics Chinese Acad. of Sci. Beijing 100029 China

Empirical orthogonal function (EOF) analysis is carried out for the year-to-year variability of the boreal winter (DJF) mass stream function of the mean meridional circulation (MMC) during the period 1948—2005. The results demonstrate that it is dominated by the equatorially asymmetric and symmetric modes. Further analysis shows that the former mode is linked with the boreal winter Hadley cell mainly on the decadal time-scale, and the latter on the interannual time-scale. The asymmetric mode index (AMI) with a clear upward trend contributes to the decadal strengthening of the boreal Hadley circulation, and is closely correlated with the tropical SST warming, especially in the region of Indo-west Pacific warm pool (INWP). Furthermore, the AMI also contributes to the abrupt change of the correlation coefficient between the boreal Hadley circulation and ENSO after 1976. The symmetric mode index (SMI) with robust and stable linkage with ENSO shows a significant interannual variability, suggesting that the variability of the Hadley circulation is mainly associated with ENSO on the interannual time-scale.

关键词： the Hadley circulation interannual time-scale decadal time-scale

Carbon nanotube transistors with graphene oxide films as gate dielectrics

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Science china(physics,Mechanics & Astronomy) 2010年第5期53卷 828-833页

作者： FU WangYang,LIU Lei,WANG WenLong,WU MuHong,XU Zhi,BAI XueDong & WANG EnGe beijing National Laboratory for Condensed Matter physics,institute of physics,chinese academy of sciences,beijing 100190,china beijing National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing China

Carbon nanomaterials,including the one-dimensional(1-D) carbon nanotube(CNT) and two-dimensional(2-D) graphene,are heralded as ideal candidates for next generation *** essential component for the development of advanced nanoelectronics devices is processing-compatible ***,in analogy to the widespread use of silicon dioxide(SiO2) in silicon microelectronic industry,we report the proof-of-principle use of graphite oxide(GO) as a gate dielectrics for CNT field-effect transistor(FET) via a fast and simple solution-based processing in the ambient *** exceptional transistor characteristics,including low operation voltage(2 V),high carrier mobility(950 cm2/V-1 s-1),and the negligible gate hysteresis,suggest a potential route to the future all-carbon nanoelectronics.

关键词： carbon-based nanoelectronics graphene oxide gate dielectrics

Anomalous dielectric behavior in nanocrystalline γ-Fe_2O_3

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chinese Science Bulletin 1999年第2期44卷 186-189页

作者： YE Xisheng , SHA Jian , CHEN Bin , JIAO Zhengkuan ZHANG LideDepartment of physics, Zhejiang University, Hangzhou 310027, china Northwest institute of Nuclear Technology, Xi’ an 710024, china institute of theoretical physics, chinese academy of sciences, beijing 100080, china institute of Solid State physics, chinese academy of sciences, Hefei 230031, china Department of physics Zhejiang University Hangzhou China Northwst institute of Nuclear Technology Xi’an China institute of theoretical physics Chinese Academy of Sciences Beijing China institute of Solid State physics Chinese Academy of Sciences Hefie China

The measurements of electric capacities and dielectric loss angles for nanocrystalline yFe2O3 under air and vacuum atmospheres have been conducted by using ac LRC method, and the conductivity and the polarization relaxation time have also been calculated from the frequency spectra of real and imaginary parts of the dielectric constants. The anomalous dielectric behavior implies the existence of two kinds of polarization mechanisms with different relaxation times, which are caused by the defects and the dangling bonds in the interfaces, respectively. The experimental and calculated results indicated that the polarization loss and the conductance loss are dominant in air atmosphere and vacuum, respectively.

关键词： nanocrystalline γ-Fe2O3 dielectric behavior polarization mechanism.