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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 {2. University,Changsha 410081,china~2.department of physics,Beijing {2. University,Beijing 100875,china~3 department of Electronic Engineering and physics,Hunan University of Science and Engineering,Yongzhou 42.100,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

X-ray spectra induced by slow highly charged Ar^(q+) ions in collision with Nb surface

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Science china(physics,Mechanics & Astronomy) 2008年第10期51卷 1463-1469页

作者： YANG ZhiHu1, CUI Ying2. CHEN XiMeng2. SONG ZhangYong1, SHAO JianXiong2. RUAN FangFang1, ZHANG HongQiang2. DU Juan2. LIU YuWen2. GAO ZhiMing2. ZHANG XiaoAn3, ZHU KeXin1, YU DeYang1 & CAI XiaoHong1 1 Institute of Modern physics, Chinese Academy of Sciences, Lanzhou 730000, china 2.{2. of Modern physics, Lanzhou University, Lanzhou 730000, china 3 {2. of physics, Xianyang normal college, Xianyang 712.00, china Institute of Modern physics Chinese Academy of Sciences Lanzhou China department of Modern physics Lanzhou University Lanzhou China department of physics Xianyang Normal College Xianyang China

The X-ray spectra of Nb surface induced by Arq+ (q =16,17) ions with the energy range from 10 to 2. keV/q were studied by the optical spectrum technology. The experimental results indicate that the multi-electron excitation occurred as a highly charged Ar16+ ion was neutralized below the metal surface. The K shell electron of Ar16+ was excited and then de-excited cascadly to emit K X-ray. The intensity of the X-ray emitted from K shell of the hollow Ar atom decreased with the increase of projectile kinetic energy. The intensity of the X-ray emitted from L shell of the target atom Nb increased with the increase of projectile kinetic energy. The X-ray yield of Ar17+ is three magnitude orders larger than that of Ar16+.

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

Density functional study on enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine

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Science china Chemistry 2006年第4期49卷 296-307页

作者： LI Ming1, ZHENG Wenxu2.& TIAN Anmin2.1. department of Chemistry, Southwest-china {2. University, Chongqing 400715, china 2. department of Chemistry, Sichuan University, Chengdu 610064, china department of Chemistry Southwest-China Normal University Chongqing China department of Chemistry Sichuan University Chengdu China

The enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine is discussed by the density functional theory (DFT) method. The main intermediates and transition states for this reaction are optimized completely at the B3LYP/6-31g(d) level, and the transition states are verified by vibrational modes. As shown, the chirality-controlled steps for this re- action are the hydride transfer from borane to carbonyl carbon and oxime carbon of keto oxime ether, and the chirality for the reduced products is determined in these two reaction steps. In all examined reaction paths, the first hydride is transferred via a six-membered ring and the second hydride via a five-membered ring or a four-membered ring.

关键词： keto oxime ether, oxazaborolidine, enantioselective reduction, DFT.

Observations favor the crossing of phantom divide lines

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Science china(physics,Mechanics & Astronomy) 2010年第3期53卷 562-566页

作者： HUANG TieTie1,2.3, WU PuXun2.3 & YU HongWei2.3 1department of physics, Xiangnan {2., Chenzhou 42.000, china 2.0} of physics and Institute of physics, Hunan normal University, Changsha 410081, china 3Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan normal University, Changsha 410081, china department of physics Xiangnan College Chenzhou China department of physics and Institute of physics Hunan Normal University Changsha China Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education Hunan Normal University Changsha China

Using three different parameterized dark energy models, we reconstruct the properties of dark energy from the latest 397 Sne Ia, CMB and BAO with the present matter density, Ωm0, given prior. We find that, when Ωm0 is not small, for example, Ωm0 = 0.2. or 0.32. an evolving dark energy with a crossing of phantom divide line is favored and this conclusion seems to be model independent. We also find that the evolving properties of dark energy become more and more evident with the increase of Ωm0 given prior.

关键词： cosmology auelerating expansion dark energy

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 {2., Chifeng 02.001, 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 11602., 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

K-uniformly rotund spaces and k-uniformly smooth spaces

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Chinese Science Bulletin 1998年第2期43卷 92-95页

作者： Suyalatu 1 and WU Congxin 2.1. department of Mathematics,Inner Mongolia normal University, Huhhot 01002.,{2. 2. department of Mathematics, Harbin Institute of Technology, Harbin 150006,{2. department of Mathematics Inner Mongolia Normal University Huhhot China department of Mathematics Harbin Institute of Technology Harbin China

The conception of k_uniform smoothness (KUS) is introduced. It is the extension of the conception of uniform smoothness. It is proved that the k_uniform smoothness and Sullivan’s K_uniform rotundity (KUR) are the daul notions. X+* is a KUR space if and only if X is a KUS space, X+* is a KUS space if and only if X is a KUR space. If X is a KUS space, then X is a (K+1)US space. It is also proved that the KUS space includes the Nan’s k_strongly smooth space.

关键词： K_uniform smoothness K_uniform convexity.

Recurrence spectra of He atoms in strong external fields

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Science china(physics,Mechanics & Astronomy) 2004年第4期47卷 477-484页

作者： LIN Shenglu1, LI Hongyun1, WANG Dehua2. ZHAO Wenli1 & GAO Feng1 1. department of physics, Shandong {2. University, Jinan 2.0014, china 2. department of Mathematics and physics, Shandong Institute of Architecture and Engineering, Jinan 2.0014, china department of physics Shandong Normal University Jinan China department of Mathematics and physics Shandong Institute of Architecture and Engineering Jinan China

By employing a model potential including the electron exchange energy, we extend the semiclassical closed orbit theory to study the multielectron atoms. Using special region-splitting consistent and iterative method, we figure out the closed orbits in the corresponding classical system and calculate the recurrence spectra of triplet helium atoms in parallel electric and magnetic fields at scaled energy ε=?0.03,n≈40,n=0. The core-scattering effects have been taken into account, which lead to more peaks in the spectra. It has also been confirmed by means of the direct comparison between the spectral portrait in such a plot and those of hydrogen case. In order to compare the theoretic results with experiment, we investigate the closed orbits and recurrence spectra of helium atoms for the similar exchange potential but applied only by single electric field at scaled energy ε=?2.7 case. The spectra are in good agreement with the experimental observation. We conclude that our model is correct and it is necessary to consider the exchange effect for determining the photoabsorption spectra of multielectron atoms in strong external fields.

关键词： exchange potential, recurrence spectra, semiclassical closed orbit theory, core-scattering.

The dynamical properties of Rydberg hydrogen atom near a metal surface

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Science china(physics,Mechanics & Astronomy) 2005年第6期48卷 667-675页

作者： GE Meihua1, ZHANG Yanhui1, WANG Dehua2. DU Mengli3 & LIN Shenglu1 1. college of physics and Electronics, Shandong {2. University, Jinan 2.0014, china 2. department of Mathematics and physics, Shandong Institute of Architecture and Engineering, Jinan 2.0014, china 3. Institute of Theoretical physics, Chinese Academy of Sciences, Beijing 100080, china college of physics and Electronics Shandong Normal University Jinan China department of Mathematics and physics Shandong Institute of Architecture and Engineering Jinan China Institute of Theoretical physics Chinese Academy of Sciences Beijing China

The dynamical properties of Rydberg hydrogen atom near a metal surface are presented by using the methods of phase space analysis and closed orbit theory. Transforming the coordinates of the Hamiltonian, we find that the phase space of the system is divided into vibrational and rotational region. Both the Poincaré surface of section and the closed orbit theory verify the same conclusion clearly. In this paper we choose the atomic principal quantum number as n = 2.. The dynamical character of the exited hydrogen atom depends sensitively on the atom-surface distance d. When d is sufficiently large, the atom-surface potential can be expressed by the traditional van der Waals force and the system is integrable. When d becomes smaller, there exists a critical value dc. For d > dc, the system is near-integrable and the motion is regular. While chaotic motion appears for d < dc, and the system tends to be non-integrable. The trajectories become unstable and the electron might be captured onto the metal surface.

关键词： Rydberg hydrogen atom, van der Waals interaction, Poincaré surface of section, closed orbit theory, chaos.

Entanglement Involved in Pair Coherent State Studied via Wigner Function Formalism

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Communications in Theoretical physics 2009年第12期52卷 1071-1075页

作者： HU Li-Yun~(1,2.and FAN Hong-Yi~2. college of physics and Communication Electronics, Jiangxi {2. University, Nanchang 33002., china2.department of physics, Shanghai Jiao Tong University, Shanghai 2.0030, china college of physics and Communication Electronics Jiangxi Normal University Nanchang 330022 China department of physics Shanghai Jiao Tong University Shanghai 200030 China

We calculate Wigner function,tomogram of the pair coherent state by using its Schmidt decompositionin the coherent state *** turns out that the Wigner function can be seen as the quantum entanglement(QE)between two two-variable Hermite polynomials(TVHP)and the tomogram is further simplified as QE of twosingle-variable Hermite *** Husimi function of pair coherent state is also calculated.

关键词： pair coherent state Wigner function Tomogram Husimi function