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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 710061 China Beijing National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China institute of modern physics Northwest University Xi’an 710069 China Department of physics Ningbo University Ningbo 315211 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

Potential energy surfaces for low-lying electronic states of SO_2

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Science china Chemistry 2006年第4期49卷 289-295页

作者： LI Anyang1, SUO Bing2, WEN Zhenyi2 & WANG Yubin2 1. Shanxi Key Laboratory of Physico-inorganic Chemistry, Department of Chemistry, northwest university, xi’an 710069, china 2. institute of modern physics, northwest university, xi’an 710069, china 1. Shanxi Key Laboratory of Physico-inorganic Chemistry Department of Chemistry Northwest University Xi’an 710069 China 2. institute of modern physics Northwest University Xi’an 710069 China

The potential energy surfaces for the nine low-lying electronic states of SO2 have been constructed by using the multi-reference second order perturbation theory (MRPT2) with the basis set cc-pVTZ. The optimized geometries and the adiabatic excitation energies of these states are in good agreement with experiments and previous calculations. The crossings and avoided crossings dis- played in the potential energy surfaces are expounded.

关键词： cross of PES, MRPT2, SO2 (sulfur dioxide).

Analytical Model of Non-dispersion-limited Transient Stimulated Raman Scattering in Single-mode Silica Fiber in WDM Optical Communication System

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Chinese Journal of Lasers 2000年第2期9卷 175-181页

作者： GONG Jiamin FANG Qiang LIU Juan WANG Yongchang (Insitute of modern physics, xi' an Jiaotang university, xi' an 710049, china Department of Telecommunications, xi' an institute of Posts and Telecommunications, xi' an 710061, china ) 西安交通大学陕西西安西安邮电学院陕西西安

The non-dispersion-limited analytic acutions of unidirectional N-channel transient stimulated Raman scattering (SRS) coupling wave equation which governing the propagation of the optical signals in single-mode (SM) silica fiber have been presented. Taking into account the SRS cross coupling among the N- channels, the analytic solutions are applicable to the system with arbitrary channel separation and input signal light power.

关键词： stimulated Raman scattering (SRS) wavelength division multiplexing (WDM) fused silica fiber Raman amplification Raman crosstalk

X-ray spectra induced by ^(12.)Xe^(q+) impacting the metal surface

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Science china(physics,Mechanics & Astronomy) 2008年第1期51卷 82-89页

作者： ZHANG xiaoAn 1,2 ,xiAO GuoQing 1 ,YANG ZhiHu 1 ,CHEN xiMeng 3 ,ZHAO YongTao 1 , LI FuLi 4 ,WANG Li 1,2 ,CUI Ying 3 ,ZHANG HongQiang 3 &ZHAN WenLong 1 1institute of modern physics,Chinese Academy of Sciences,Lanzhou 730000,china 2Department of physics,xianyang Normal university,xianyang 712.00,china 3Department of modern physics,Lanzhou university,Lanzhou 730000,china 4Department of Applied physics,xi’an Jiaotong university,xi’an 710049,china 1. institute of modern physics Chinese Academy of Sciences Lanzhou 730000 China 2. Department of physics Xianyang Normal University Xianyang 712000 China 3. Department of modern physics Lanzhou University Lanzhou 730000 China 4. Department of Applied physics Xi’an Jiaotong University Xi’an 710049 China

Using the slow highly charged ions 12. Xe q+ (q=25,26,27;initial kinetic T0≤4.65 keV/a.u.)to impact Au surface,the Au atomic Mαcharacteristic X-ray spectrum is *** result shows that as long as the charge state of projectile is high enough,the heavy atomic characteristic X-ray can be effectively excited even though the incident beam is very weak(nA magnitude),and the X-ray yield per ion is in the order of 10-8and increases with the kinetic energy and potential energy of *** measuring the Au Mα-X-ray spectra,Au atomic N-level lifetime is estimated at about 1.33×10-18s based on Heisenberg uncertainty relation.

关键词： slow highly charged ions characteristic X-ray level lifetime

Classification and Functional Separable Solutions to Extended Nonlinear Wave Equations

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Communications in Theoretical physics 2005年第10期44卷 589-596页

作者： ZHANG Shun--Li LOU Sen--Yue QU Chang--Zheng YUE Rui--Hong institute of modern physics, northwest university, xi'an 710069, china Department of Mathematics, northwest university, xi'an 710069, china Center of Nonlinear Science, Ningbo university, Ningbo 315211, china Department of physics, Shanghai Jiao Tong university, Shanghai 200030, china institute of modern physics Northwest University Department of Mathematics Northwest University Center of Nonlinear Science Ningbo University Department of physics Shanghai Jiao Tong University

The generalized conditional Symmetry approach is applied to study the variable separation of the extendedwave equations. Complete classification of those equations admitting functional separable solutions is obtained ... 详细信息

关键词： nonlinear wave equations functional separable solutions generalized conditional symmetry

Electronic structure and magnetism of Fe-doped SiC nanotubes

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Science china(physics,Mechanics & Astronomy) 2010年第9期53卷 1582-1589页

作者： ZHANG WeiHu1,2,3,ZHANG FuChun3,ZHANG ZhiYong4,LU ShuYuan5 & YANG YanNing3 1 xi’an institute of Optics and Precision Mechanics,Chinese Academy of Sciences,xi’an 710068,china 2 Graduate university of Chinese Academy of Sciences,Beijing 100049,china 3 College of physics and Electronic Information,Yan’an university,Yan’an 716000,china 4 Information Science and Technology Institution,northwest university,xi’an 71012.,china 5 Department of Telecommunications,xi’an institute of Posts and Telecommunications,xi’an 71012.,china 1. xi’an institute of Optics and Precision Mechanics Chinese Academy of Sciences Xi’an 710068 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. College of Physics and Electronic Information Yan’an University Yan’an 716000 China4. Information Science and Technology Institution Northwest University Xi’an 710127 China5. Department of Telecommunications Xi’an Institute of Posts and Telecommunications Xi’an 710121 China

The electronic structure and magnetic properties of Fe-doped SiC nanotubes are investigated by using the first-principles method based on density functional theory(DFT) in the local spin density approximation(LSDA).The calculation results indicate that the SiC nanotube of Fe substitution for C exhibits antiferromagnetism while ferromagnetism features prominently when Fe substitutes *** is a kind of half-metal magnetic *** formation energy calculation results show that the formation energy of ferromagnetic structure is 3.2 eV lower than that of antiferromagnetic *** atoms are more likely to replace Si ***-orbit coupling induces electron spin polarization in the ground ***,the doping Fe atoms make relaxation towards the outside of the tube to some extent and larger geometric distortion occurs when Fe substitutes C,but the whole geometric structure of SiC nanotubes is not damaged due to the *** is revealed in the calculation of energy band structure and density of states that more dispersed distribution of energy levels is produced near the Fermi *** Fe substitution for Si,obviously there are spin-split and intense p-d hybrid effects by Si 3p electron spins and Fe 3d electron spins localized at the exchanging interactions between magnetic transitional metal(TM) *** electronic density results indicate that system magnetic moments are mainly generated by the unpaired 3d electrons of Fe *** these results show that the transition metal doping SiC nanotube could be a potential route to fabricating the promising magnetic materials.

关键词： SiC nanotube the first-principles doped magnetic properties

X-ray spectra induced in highly charged 40Ar^q+ interacting with Au surface

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Science china(physics,Mechanics & Astronomy) 2006年第2期49卷 203-212页

作者： ZHANG xiao’an1,2, xiAO Guoqing1, YANG Zhihu1, CHEN ximeng3, ZHAO Yongtao1, LI Fuli4, ZHANG Yinping1, CUI Ying3, ZHANG Hongqiang3, XU Xu3, SHAO Jianxiong3 & ZHAN Wenlong11. institute of modern physics, Chinese Academy of Sciences, Lanzhou 730000, china 2. Department of physics, xianyang Normal university, xianyang 712.00, china 3. Department of modern physics, Lanzhou university, Lanzhou 730000, china 4. Department of Applied physics, xi’an Jiaotong university, xi’an 710049, china 1. institute of modern physics Chinese Academy of Sciences Lanzhou 730000 China 2. Department of physics Xianyang Normal University Xianyang 712000 China 3. Department of modern physics Lanzhou University Lanzhou 730000 China 4. Department of Applied physics Xi’an Jiaotong University Xi’an 710049 China

By use of optical spectrum technology, the spectra of X-ray induced by highly charged 40Arq+ ions interacting with Au surface have been studied. The results show that the argon Kα X-ray were emitted from the hollow atoms formed below the surface. There is a process of multi-electron exciting in neutralization of the Ar16+ion, with electronic con-figuration 1s2 in its ground state below the solid surface. The yield of the projectile Kα X-ray is related to its initial electronic configuration, and the yield of the target X-ray is related to the projectile kinetic energy.

关键词： highly charged ion hollow multi-electron excitation X- ray.

Parameter Estimation of Sub-/Super-synchronous Oscillation Based on Interpolated All-phase Fast Fourier Transform with Optimized Window Function

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Journal of modern Power Systems and Clean Energy 2024年第4期12卷 1031-1041页

作者： Bo Sun xi Wu xi Chen Zixiao Zou Qiang Li Bixing Ren School of Electrical Engineering Southeast UniversityNanjingChina State Grid Jiangsu Electric Power Company Limited Research institute NanjingChina

In recent years,with increasing amounts of renew-able energy sources connecting to power grids,sub-/super-syn-chronous oscillations(SSOs)occurred more *** to the time-variant nature of SsO magnitudes and frequencies,as well as the mutual interferences among SsO modes with close frequencies,the accurate parameter estimation of SsO has be-come a particularly challenging *** solve this issue,this paper proposes an improved spectrum analysis method by im-proving the window function and a spectrum correction method to achieve higher ***,by aiming at the sidelobe characteristics of the window function as evaluation criteria,a combined cosine function is optimized using a genetic algorithm(GA).Furthermore,the obtained window function is self-con-volved to extend its excellent characteristics,which have better performance in reducing mutual interference from other SSO ***,a new form of interpolated all-phase fast Fourier transform(IpApFFT)using the optimized window func-tion is proposed to estimate the parameters of *** meth-od allows for phase-unbiased estimation while maintaining algo-rithmic simplicity and *** performance of the pro-posed method is demonstrated under various conditions,com-pared with other estimation *** results vali-date the effectiveness and superiority of the proposed method.

关键词： Sub-/Super-synchronous oscillation(SSO) window function parameter estimation interpolated all-phase fast Fourier transform(ApFFT)

DFT Thermodynamic Research of the Pyrolysis Mechanism of the Carbon Matrix PrecursorTol uene for Carbon Material

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Chemical Research in Chinese Universities 2001年第2期17卷 219-225页

作者： WANG Hui, YANG Hai-feng, RAN xin-quan WEN Zheng-yi and SHI Qi-zhen (Chemistry Department, modern physics institute and, Key Laboratory of physics Inorganic Chemistry of Shan-xi Province, northwest university, xi’an 710069, P. R. china) NW Univ xian Dept Chem Xian 710069 Peoples R China NW Univ xian Inst Modern Phys Xian 710069 Peoples R China NW Univ xian Key Lab Phys Inorgan Chem Shan Xi Province Xian 710069 Peoples R China

Based on the experiments, the standard enthalpy△H■of the possible pyrolysis reactions of the carbon matrix precursor toluene was investigated by means of DFT method UB3LYP/ 3-21G *(based on semi-empirical method UAM1 and ab initio method UHF/3-21G*). The com- putation results with UB3LYP/3-21G* coincide with the experimental values well. Then, the mechanism for all types of the pyrolysis reactions of toluene was studied by UB3LYP/3-21G * The geometries of the reactant and the product radicals were optimized, meanwhile, the standard thermodynamic parameters of the pyrolysis reaction at different temperatures (298, 773, 843, 963 and 1 073 K) were calculated. The thermodynamic computation result shows that when the pyrolysis temperature of toluene is lower than 963 K, the reaction path supported by thermody- namics is that the C-H bond of the methyl on the benzene ring breaks and bitoluene form, while the temperature increases (about 1 073 K), the thermodynamic calculation result turns to support the reaction path producing phenyl radicals and methyl radicals. This mechanism is in accord with the experiments.

关键词： Carbon/carbon composites Toluene Pyrolysis mechanism UB3LYP/3-21G