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Implementation of a multiple round quantum dense coding using nuclear magnetic resonance

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Science china(Physics,Mechanics & Astronomy) 2005年第6期48卷 706-715页

作者： ZHANG Jingfu1, XIE Jingyi2. WANG Chuan1, DENG Zhiwei3, LU Zhiheng4, & LONG Guilu1,5 1. Key Laboratory For Quantum Information and Measurements of MOE, department of Physics, Tsinghua university, {2. 100084,china 2. department of Materials Science and Engineering, beijing normal university, beijing 100875, china 3. Testing and Analytical Center, beijing normal university, beijing 100875,china 4. department of Physics, beijing normal university, beijing 100875, china 5. Key Laboratory For atomic and Molecular Nanosciences, Tsinghua university, {2. 100084,china 1. Key Laboratory For Quantum Information and Measurements of MOE Department of Physics Tsinghua University 100084 Beijing China 2. department of Materials science and Engineering Beijing Normal University 100875 Beijing China 3. Testing and Analytical Center Beijing Normal University 100875 Beijing China 4. department of Physics Beijing Normal University 100875 Beijing China 5. Key Laboratory For Atomic and Molecular Nanosciences Tsinghua University 100084 Beijing China

A multiple round quantum dense coding scheme based on the quantum phase estimation algorithm is proposed and implemented in a three qubit nuclear magnetic resonance (NMR) quantum computer. Using an m + 1 qubit system, Bob can transmit one of 2.+1 messages to Alice, through manipulating only one qubit and exchanging it between Alice and Bob for m rounds. The information capacity is enhanced to m + 1 bits as compared to m bits in a classical scheme. The scheme has been demonstrated in NMR system, and the experimental results show a good agreement between theory and experiment.

关键词： quantum dense coding, multiple round, nuclear magnetic resorance

On asymptotics of t-type regression estimation in multiple linear model

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Science china Mathematics 2004年第4期47卷 628-639页

作者： GUI Hengjiandepartment of Mathematics, beijing normal university,{2., china 1. department of Mathematics Beijing Normal University 100875 Beijing China

We consider a robust estimator (t-type regression estimator) of multiple linear regression model by maximizing marginal likelihood of a scaled t-type error *** marginal likelihood can also be applied to the de-correlated response when the withinsubject correlation can be consistently estimated from an initial estimate of the model based on the independent working assumption. This paper shows that such a t-type estimator is consistent.

关键词： t-type regression estimator, M-estimator, one-step estimate, consistency, asymptotic normality.

THE HAUSDORFF MEASURE FOR THE SAMPLE PATH OF THE WESTWATER PROCESS

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Chinese Annals of Mathematics,Series B 1996年第3期17卷 375-388页

作者： ZHOU XIANYIN(Depatment of Mathematics, beijing normal university beijing 100875,{2.) beijing normal UNIV DEPT MATHBEIJING 100875PEOPLES R CHINA

It is proved that φ(s) = s2.log |logs| is the correct function to give the Hausdorff measureof a sample path of the Westwater process.

关键词： Hausdorff measure Wiener process Westwater process Sojourn time

Constraints on Cardassian universe from Gamma ray bursts

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Science china(Physics,Mechanics & Astronomy) 2010年第9期53卷 1720-1725页

作者： WANG TaiShan1 & LIANG Nan2.1 department of Physics & Center for Astrophysics,Tsinghua university,{2. 100084,china 2.department of Astronomy,{2. normal university,{2. 100875,china 1. department of Physics & Center for Astrophysics Tsinghua University Beijing 100084 China2. Department of Astronomy Beijing Normal University Beijing 100875 China

Constraints on the original Cardassian model and the modified polytropic Cardassian model are examined from the recently derived 42.gamma-ray bursts(GRBs) data calibrated with the method that can avoid the circularity *** results show that GRBs can be an optional observation to constrain the Cardassian *** the GRBs data with the newly de-rived size of baryonic acoustic oscillation peak from the Sloan Digital Sky Survey(SDSS),and the position of the first acoustic peak of the Cosmic Microwave Background radiation(CMB) from Wilkinson Microwave Anisotropy Probe(WMAP),we find Ωm0=0.2.+0.02.0.02.n=0.06+0.07-0.08(1σ) for the original Cardassian model,and Ωm0=0.2.+0.2.-0.02.n=-0.09+0.2.-1.91,β=0.82.2.10-0.62.1σ) for the modified polytropic Cardassian model.

关键词： Cardassian Gamma ray burst Cosmic Microwave Background baryonic acoustic oscillation

Linear estimation and distribution of the limit cycles bifurcated from a kind of degenerate polycycles

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Science china Mathematics 2007年第3期50卷 334-344页

作者： Li-qin ZHAO department of Mathematics, beijing normal university,{2., china department of Mathematics Beijing Normal University Beijing 100875 China

In this paper, we investigate the number and the distribution of the limit cycles bifurcated from a kind of degenerate planar polycycles through three singular points: a saddle-node P 0, a fine saddle P 1 with finite order m ∈ N, a contractive (attracting) saddle P 2.with the hyperbolicity ratio q 2.0) ? Q. The connection between P 0 and P 1 is of hh-type and the connection between P 0 and P 2.is of hp-type. It is assumed that the connections between P 0 to P 2.and P 0 to P 1 keep unbroken. We obtain that the cyclicity of this polycycle is not more than 3m + 1, which is linearly dependent on the order of the resonant saddle P 1. We also show that the cyclicity is not more than m + 3 if q 2.0) > m, and that the nearer q 2.0) is close to 1, the more the limit cycles are bifurcated.

关键词： degenerate polycycle cyclicity finitely-smooth normal form transition map 34C05 34C2. 58F14

The Goldbach 3-primes property for polynomial rings over certain infinite fields

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Chinese Science Bulletin 1998年第15期43卷 1256-1260页

作者： WANG Shiqiang department of Mathematics, beijing normal university,{2., china department of Mathematics Beijing Normal University Beijing China

On the basis of Effinger and Hayes’ theorem about the Goldbach 3_primes property of polynomial rings F over finite fields F , by model_theoretic method it is proved that for each characteristic k (including 0), there... 详细信息

关键词： model theory polynomial 3 primes property.

Quasi-critical ring of a primitive ring with nonzero socle

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Chinese Science Bulletin 1997年第3期42卷 189-192页

作者： JIANG Zimeidepartment of Mathematics, beijing normal university,{2., china department of Mathematics Beijing Normal University Beijing China

IN ref. [1] Jacobson proved the structure theorem for primitive rings with nonzero socles that R is a primitive ring withsocle S≠{0} if and only if there is a pair of dual vector spaces (M,M’) over a division ring ... 详细信息

IN ref. [1] Jacobson proved the structure theorem for primitive rings with nonzero socles that R is a primitive ring withsocle S≠2. if and only if there is a pair of dual vector spaces (M,M’) over a division ring Δ such that S=F(M, M’)(?) R(?)(?)(M, M’), where (?)(M, M’)-{ω∈Ω|ωM’(?)M’, Ω is the complete ring of linear transformations of M over Δ}, F(M, M’) is the set of all linear transformations of (?)(M, M’) of finite rank. After that, some people reproved this theorem by using different methods such as those in refs. [2. 3]. In

关键词： primitive ring socle conjugate space total subspace of conjugate space.

Particle tunnels across the horizon of Garfinkle-Horowitz-Strominger dilaton black hole

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Science china(Physics,Mechanics & Astronomy) 2007年第5期50卷 601-610页

作者： FANG HengZhong1 & ZHAO Zheng2.1 department of Physics, china {2. of Petroleum, Dongying 2.7061, china 2.department of Physics, beijing normal university, beijing 100875, china department of Physics China University of Petroleum Dongying 257061 China department of Physics Beijing Normal University Beijing 100875 China

We promote the work of Parikh and Wilczek on the black hole radiation to the emission of massive and charged particles from Garfinkle-Horowitz-Strominger black hole. The energy and charge of the space-time are conservational during the course of the evaporation. The calculation shows that the emission spectrum is not precisely thermal, while has a correction, and the conclusion supports the view- point of information conservation.

关键词： Hawking radiation, black body spectrum, barrier, information loss, entropy of black hole, Komar energy

Theoretical study on thermal decomposition of azoisobutyronitrile in ground state

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Science china Chemistry 2004年第5期47卷 373-380页

作者： SUN Chengke1,2. ZHAO Hongmei1 & LI Zonghe1 1. department of Chemistry, beijing normal university,{2., china 2. department of Chemistry, Qujing normal College, Qujing 655000, china 1. department of Chemistry Beijing Normal University 100875 Beijing China 2. department of Chemistry Qujing Normal College 655000 Qujing China

The thermal decomposition mechanisms of azoisobutyronitrile (AIBN) in the ground state have been investigated systematically. Based on the potential energy surfaces (PES) of various possible dissociation paths obtained using the semiempirical AM1 method with partial optimization, the density function theory B3LYP/6-311G* method was employed to optimize the geometric parameters of the reactants, the intermediates, the products and the transition states, which were further confirmed by the vibrational analysis. The obtained results show that the re- action process of the two-bond (three-body) simultaneous cleavage Me2.CN)C─ N=N─ C(CN)Me2. 2.e2.CN)C?+N2.is much more favorable than the reaction process of the two one- bond asynchronous cleavage Me2.CN)CN=N─C(CN)Me2.? Me2.CN)CN=N?+ Me2.CN)C?? Me2.CN)C?+ N2. It was suggested that the electron shrinking effect of double bond (─N=N─) in AIBN and the stabilities of the Me2.CN)C?radical as well as N2.molecule are main factors of leading to the reaction proceeding in the former pathway. The calculation results were consistent with all the experimental facts.

关键词： azoisobutyronitrile, radicals, thermal decomposition, density function theory (DFT).