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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 0.34.2 (for odd-qubit chain) or 0.34.1 (for even-qubit chain) if the qubit number is large enough.

关键词： Heisenberg XX model local polarization pairwise entanglement

Optimal reactions for the synthesis of superheavy nucleus ^(270)Hs

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Science china(physics,Mechanics & Astronomy) 2006年第6期49卷 641-648页

作者： LIU Zuhua1,3 & BAO Jingdong1,2 1. Key Laboratory of Beam Technology and Material Modification of Ministry of Education, beijing Normal University, beijing 100875, china 2. physics {4., beijing Normal University, beijing 100875, china 3. china Institute of Atomic Energy, beijing 1024.3, china Key Laboratory of Beam Technology and Material Modification of Ministry of Education Beijing Normal University Beijing China china Institute of Atomic Energy Beijing China physics department Beijing Normal University Beijing China

The superheavy nucleus 270Hs is expected to be a “double-magic” deformed nucleus. We have calculated its cross sections of evaporation residue for the reactions 24.Cm(26Mg,4.)270Hs, 24.Pu(30Si,4.)270Hs, 238U(36S,4.)270Hs and 226Ra(4.Ca,4.)270Hs using a two-parameter Smoluchowski equation. It is found from our results that 226Ra(4.Ca,4.)270Hs and 238U(36S,4.)270Hs are two optimal reactions for the synthesis of the superheavy nucleus 270Hs due to their large negative Q-values.

关键词： diffused fusion barrier,Smoluchowski equation,superheavy nuclei.

Estimate of Exponential Convergence Rate in Total Variation by Spectral Gap

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Acta Mathematica Sinica,English Series 1998年第1期14卷 9-16页

作者： Chen Mufa department of Mathematics, beijing Normal University, beijing 100875, china 北京师范大学数学系北京

This note is devoted to study the exponential convergence rate in the total variation for reversible Markov processes by comparing it with the spectral gap. It is proved that in a quite general setup, with a suitable restriction on the initial distributions, the rate is bounded from below by the spectral gap. Furthemore, in the compact case or for birth-death processes or half-line diffosions, the rate is shown to be equal to the spectral gap.

关键词： Total variation Spectral gap Markov processes

Progress in the study of molecular organized assemblies by dielectric relaxation spectroscopy

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Progress in Natural Science:Materials International 2006年第3期16卷 221-230页

作者： ZHAO Kongshuang, HE Kejuan and WEI Suxiang (department of Chemistry, beijing Normal University, beijing 100875, china department of Chemistry, South china Normal University, Guangzhou 510631, china) department of Chemistry Beijing Normal University Beijing 100875 China department of Chemistry South China Normal University Guangzhou 510631 China

Because dielectric spectroscopy covers a great many problems in physical and chemical systems occurring in an extremely wide frequency range, the study of this method plays an important role in physical chemistry. As an effective tool to detect inner properties of substance systems, the dielectric spectroscopy method is widely used in chemical systems and has been dramatically developed in recent decade. This review paper describes the applications of the dielectric spectroscopy in the chemical field, and main concentrations are focused on the micelle, microemulsion and other so-called molecular organized assemblies. Some dielectric principles and models proposed for these systems are introduced. In addition, recent technical developments in dielectric spectroscopy and developing trend of this method in other chemical systems are reviewed.

关键词： dielectric relaxation micelle microemulsion vesicle relaxation time.

|m| Partial wave treatment for two-dimensional Coulomb-scattering and Regge pole

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Science china(physics,Mechanics & Astronomy) 2004年第6期47卷 676-684页

作者： WANG Jing & ZENG Jinyan department of physics,Tsinghua University,beijing 100084.china School of physics,Peking University,beijing 100871,china department of physics Tsinghua University Beijing 100084 China School of physics Peking University Beijing 100871 China

The symmetry and |m| partial-wave analysis for two-dimensional (2D) Coulomb-scattering is investigated. As a function of energyE, the |m| partial-wave scattering amplitudef |m|(θ) is analytically continuated to the, negativeE (complexk) plane, and it is found that the bound state energy eigenvalues (E<0) are just located at the poles off |m|(θ) on the positive imaginaryk axis as is expected. In addition, as a function of |m|,f |m|(θ) is analytically continuated to the complex |m| plane, the bound state energy eigenvalues are just located at the poles off |m|(θ) on the positive real |m| axis.

关键词： two-dimensional Coulomb scattering, |m| partial-wave, Regge pole.

On the stability of diffusion processes with state-dependent switching

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Science china Mathematics 2006年第9期49卷 1258-1274页

作者： XI Fubao & ZHAO Liqin department of Mathematics, beijing Institute of Technology, beijing 100081, china School of Mathematical Sciences, beijing Normal University, beijing 100875, china department of Mathematics Beijing Institute of Technology Beijing China School of Mathematical Sciences Beijing Normal University Beijing China

In this paper we consider the stability for diffusion processes with state-dependent switching. We first prove their Feller continuity by the coupling methods. Furthermore, we also prove their strong Feller continuity and their exponential ergodicity under some reasonable conditions. Finally, we append a very brief discussion about the regularity of these processes.

关键词： Feller continuity, coupling, strong Feller continuity, exponential ergodicity,state-dependent switching.

Target-Scarching on Percolation

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Communications in Theoretical physics 2005年第9期44卷 431-434页

作者： YANG Shi--Jie department of physics, beijing Normal University, beijing 100875, china

We study target-searching processes on a percolation, on which a hunter tracks a target by smelling odorsit emits. The odor intensity is supposed to be inversely proportional to the distance it propagates. The Monte Carlosimulation is performed on a 2-dimensional bond-percolation above the threshold. Having no idea of the location of thetarget, the hunter determines its moves only by random attempts in each direction. For lager percolation connectivityP0.90, it reveals a scaling law for the searching time versus the distance to the position of the target. The scalingexponent is dependent on the sensitivity of the hunter. For smaller P, the scaling law is broken and the prohability offinding out the target significantly reduces. The hunter seems trapped in the cluster of the percolation and can hardlyreach the goal.

关键词： percolation searching scaling law

Bell States and Two-Qubit Logic Gate with Superconducting Charge Qubits Coupling to a Nanomechanical Resonator

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Communications in Theoretical physics 2007年第12期48卷 999-1002页

作者： LIAO Jie-Qiao~1 and WANG Xin-Wen~(2,3)~1 department of physics,Hunan Normal University,Changsha 4.0081,china~2 department of physics,beijing Normal University,beijing 100875,china~3 department of Electronic Engineering and physics,Hunan University of Science and Engineering,Yongzhou 4.5100,china department of physics Hunan Normal University Changsha 410081 China department of physics Beijing Normal University Beijing 100875 China department of Electronic Engineering and physics Hunan University of Science and Engineering Yongzhou 425100 China

We propose a scheme for generating Bell states involving two SQUID-based charge qubits by coupling themto a nanomechanical *** also show that it is possible to implement a two-qubit logic gate between the twocharge qu... 详细信息

关键词： Bell states superconducting charge qubit two-qubit logic gate nanomechanical resonator

STUDY OF Ag DIFFUSION INTO Cu SINGLE CRYSTALS BY RUTHERFORD BACKSCATTERING SPECTROMETRY

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Acta Metallurgica Sinica(English Letters) 2003年第5期16卷 332-334页

作者： R.Wang 1) Key Laboratory of Beam Technology and Materials Modification, Ministry of Education, beijing 100875, china2) Institute of Low Energy Nuclear physics, beijing Normal University, beijing 100875, china3) beijing Radiation Center, beijing 100875, china Lab. of Beam Technol. Inst. of Low Energy Nucl. Phys. Beijing Normal Univ. Beijing 100875 China beijing Radiation Ctr. Beijing 100875 China

4.0Me V 7Li++ RBS was used for investigations of thermal diffusion of Ag in Cu single crystals. The annealing of samples was carried out in vacuum in the temperature range from 4.8K to 613K. The element depth concentration profiles transformed from RBS spectra indicate that the diffusion of Ag into Cu is a typical volume diffusion. The Arrhenius parameters corresponding to the diffusion were obtained.

关键词： Ag diffusion single crystal