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The Monte Carlo Generator for J／ψ Decays with Angular Distribution

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Chinese Physics Letters 2005年第6期22卷 1309-1311页

作者：平荣刚杜书先 ccast(worldlaboratory) POBox8730Beijing100080//InstituteofHighEnergyPhysicsChineseAcademyofSciencesBeijing100049 InstituteofHighEnergyPhysics ChineseAcademyofSciencesBeijing100049

We present a Monte Carlo scheme to generate events of J/psi decays with angular distributions based on the acceptance-rejection sampling method. We test this scheme with J/psi -> p (p) over bar and J/psi -> Lambda(Lambda) over bar -> p (p) over bar pi(+)pi(-), and the results show that the input angular distributions are well reproduced, and efficiency of the HOWL generator of this scheme is also discussed.

关键词： DETECTOR MONTE-CARLO CALCULATION Scheme Monte Carlo technique Hypoderma MONTE CARLO THEORY Decay Bar Angular distribution peak-to-peak

Comparison Sutdy of Critical Properties of the Bond—Diluted Blume—Capel Model under the Condition of Two Different Random Crystal Fields

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Communications in Theoretical Physics 2003年第4期39卷 481-486页

作者： YANShi－Lei DENGLing－Ling ccast（worldlaboratory） P.O.Box8730Beijing100080China DepartmentofPhysics SuzhouuniversitySuzhou215006China

Citical properties of the bond diluted Blume-Capel model with random crystal filed are considered in the framework of the effective field *** emphasis is places on the comparison study of critical properties under the condition of two different random crystal fleds on square *** results show that the random crystal field plays an important role in the determination of the order of phase *** distributions of diffeeent random crystal fields,such as symmetrical and dilution crystal field,lead to apparent charactersitic *** not only give the description of a detailed phase diagram but also compare the difference between the critical properties of two different random crystal field *** comparison study has not been revealed in previous reports.

关键词：铁磁体无粘结力 Blume-Capel模型晶体场相变对比研究临界性质

Probabilistic Teleportation of One-Particle State of S-level

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Communications in Theoretical Physics 2003年第3X期40卷 273-278页

作者： YANFeng-Li BAIYan-Kui ccast(worldlaboratory) P.O.Box8730Beijing100080China DepartmentofPhysics HebeiNormalUniversityShijiazhuang050016China

A scheme for probabilistically teleporting an unknown one-particle state of S-level by a group of pairs of partially entangled 2-level particle state is proposed. In this scheme unitary transformation and local measurement take the place of Bell state measurement, then proper unitary transformation and the measurement on an auxiliary qubit with the aid of classical communication are performed. In this way the unknown one-particle state of S-level can be transferred onto a group of remote 2-level particles with certain probability. Furthermore, the receiver can recover the initial signal state on an S-level particle at his hand.

关键词：直接傅里叶变换概率输运二阶粒子态量子输运量子态量子论局部测量

Projection Operator and Propagator for an Arbitrary Half—Integral Spin

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Chinese Physics Letters 2003年第2期20卷 209-212页

作者：黄时中阮图南等 DepartmentofPhysics AnhuiNormalUniversityWuhu241000 ccast(worldlaboratory) POBox8730Beijing100080 DepartmentofModernPhysics UniversityofScienceandTechnologyofChinaHefei230027

Based on the solution to Bargmann-Wigner equation for an arbitrary half-integral spin, a direct derivation of the projection operator and propagator for an arbitrary half-integral spin is presented. The projection operator constructed by Behrends and Fronsdal is confirmed and simplified. The commutation rules and a general expression for the Feynman propagator for a free particle with arbitrary half-integral spin are deduced. Explicit expressions for the propagators for spins 3/2, 5/2 and 7/2 are provided.

关键词： HELICITY-COUPLING AMPLITUDES BARGMANN-WIGNER EQUATION COVARIANT

Ionization of Atoms and the Thomas－Fermi Model for the Electric Field in Crystal Planar Channels

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Communications in Theoretical Physics 2002年第9期37卷 361-364页

作者： LIUYing－Tai ZHANGQi－Ren DepartmentofPhysics PekingUniversityBeijing100871China ccast（worldlaboratory） P.O.Box8730Beijing100080China

The electric field in the crystal planar channels is studied by the Thomas-Fermi method. The Thomas-Fermi equation and the corresponding boundary conditions are derived for the crystal planar channels. The numerical solution for the electric field in the channels between (110) planes of the single crystal silicon and the critical angles of channelling protons in them arc shown. Reasonable agreements with the experimental data are obtained. The results show that the Thomas-Fermi method for the crystal works well in this study, and a microscopic research of the channel electric field with the contribution of all atoms and the atomic ionization being taken into account is practical.

关键词： ionization of atoms Thomas-Fermi method for the crystal electric field in channels

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Heisenberg Model in a Rotating Magnetic Field

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Communications in Theoretical Physics 2005年第4期43卷 621-626页

作者： LINQiong-Gui DepartmentofPhysics SunYat-SenUniversityGuangzhou510275China／／CCAST（WorldLaboratory）P.O.Box8730Beijing100080China

We study the Hcisenberg moder under the influence of a rotating magnetic field. By using a time- dependent unitary transformation, the time evolution operator for the Schrodinger equation is obtained, which involves no chronological product. The spin vectors (mean values of the spin operators) are obtained as explicit functions of time in the most general case. A series of cyclic solutions are presented. The nonadiabatic geometric phases of these cyclic solutions are caleulated, and are expressed in terms of the solid angle subtended by the closed trace of thc total spin vector, as well as in terms of those of the individual spins.

关键词： Heisenberg model rotating magnetic field cyclic solutions geometric phase

Projection Operator and Propagator for an Arbitrary Integral Spin

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Chinese Physics Letters 2002年第12期19卷 1767-1770页

作者：黄时中吴宁等 DepartmentofPhysics AnhuiNormalUniversityWuhu241000 ccast(worldlaboratory) POBox8730Beijing100080 InstituteofHighEnergyPhysics ChineseAcademyofSciencesBeijing100039

Based on the solution of the Bargmann-Wigner equation for an arbitrary integral spin, a direct derivation of the projection operator and propagator for an arbitrary integral spin is presented. The explicit form for the spin projection operators constructed by Behrends and Fronsdal is confirmed, the commutation rules and a general expression for the Feynman propagator for a free particle of arbitrary integral spin are deduced.

关键词： HELICITY-COUPLING AMPLITUDES COVARIANT

Enhancement of Magnetoresistance in Granular CrO2／Polystyrene Composites

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Chinese Physics Letters 2003年第9期20卷 1578-1581页

作者：陈亚杰张晓渝李振亚 LaboratoryofSolidStateMicrostructures NanjingUniversityNanjing210093 DepartmentofPhysics SuzhouUniversitySuzhou215006 ccast(worldlaboratory) POBox8730Beijing100080

We present a study of magnetotransport in CrO2/polystyrene (PS) composites over a range of polystyrene concentration (0-30 wt.%). In the experiment, an obvious enhancement in magnetoresistance (MR) is observed at 77 K and at room temperature as the half-metallic CrO2 particles are encapsulated with a thin layer of insulating polystyrene. The enhanced MR can be interpreted in terms of spin-dependent intergranular tunneling with 4-nm-thick PS barrier. Moreover, it is found that the novel PS barrier contributes to room-temperature MR more significantly than that at 77 K. Temperature dependence of resistance is good agreement with ～ T-1/4 in the temperature range from 77 to 298 K.

关键词： Polystyrenes

Explicit and Dynamical Chiral Symmetry Breaking in an Effective Quark-Quark Interaction Model

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Chinese Physics Letters 2004年第1期21卷 43-46页

作者：宗红石吴小华侯丰尧赵恩广 DepartmentofPhysics NanjingUniversityNanjing210093 DepartmentofPhysics SichuanUniversityChengdu610064 ccast(worldlaboratory) POBox8730Beijing100080

A method for obtaining the small current quark mass effect on the dressed quark propagator from an effective quark-quark interaction model is developed. Within this approach both the explicit and dynamical chiral symm... 详细信息

关键词： Physical properties