2016年, 第65卷, 第05期　
刊出日期：2016-05-01

  

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  Rashba Effect in Presence of Time-Dependent Interaction

  Hadi Sobhani, Hassan Hassanabadi

  理论物理通讯. 2016, 65(05): 543-545.

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  Rashba effect in presence of a time-dependent interaction has been considered. Then time-evolution of such a system has been studied by using Lewis-Riesenfeld dynamical invariant and unitary transformation method. So appropriate dynamical invariant and unitary transformation according the considered system have been constructed as well as some special cases have come into this article which are common in physics.
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  Lump Solution of (2+1)-Dimensional Boussinesq Equation

  马红彩, 邓爱平

  理论物理通讯. 2016, 65(05): 546-552.

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  A class of lump solutions of (2+1)-dimensional Boussinesq equation are obtained with the help of Maple by using Hirota bilinear method. Some contour plots with different determinant values are sequentially made to show that the corresponding lump solution tends to zero when the determinant approaches zero. The particular lump solutions with specific values of the involved parameters are plotted, as illustrative examples.
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  Recovering Navier-Stokes Equations from Asymptotic Limits of the Boltzmann Gas Mixture Equation

  Carlo Bianca, Christian Dogbe

  理论物理通讯. 2016, 65(05): 553-562.

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  This paper is devoted to the derivation of macroscopic fluid dynamics from the Boltzmann mesoscopic dynamics of a binary mixture of hard-sphere gas particles. Specifically the hydrodynamics limit is performed by employing different time and space scalings. The paper shows that, depending on the magnitude of the parameters which define the scaling, the macroscopic quantities (number density, mean velocity and local temperature) are solutions of the acoustic equation, the linear incompressible Euler equation and the incompressible Navier-Stokes equation. The derivation is formally tackled by the recent moment method proposed by [C. Bardos, et al., J. Stat. Phys. 63 (1991) 323] and the results generalize the analysis performed in [C. Bianca, et al., Commun. Nonlinear Sci. Numer. Simulat. 29 (2015) 240].
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  Solving Space-Time Fractional Differential Equations by Using Modified Simple Equation Method

  Melike Kaplan, Arzu Akbulut, Ahmet Bekir

  理论物理通讯. 2016, 65(05): 563-568.

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  In this article, we establish new and more general traveling wave solutions of space-time fractional Klein-Gordon equation with quadratic nonlinearity and the space-time fractional breaking soliton equations using the modified simple equation method. The proposed method is so powerful and effective to solve nonlinear space-time fractional differential equations by with modified Riemann-Liouville derivative.
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  Exact Solutions of Schrödinger Equation with Improved Ring-Shaped Non-Spherical Harmonic Oscillator and Coulomb Potential

  Akpan Ndem Ikot, Ita O. Akpan, T. M. Abbey, Hassan Hassanabadi

  理论物理通讯. 2016, 65(05): 569-574.

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  We propose improved ring shaped like potential of the form, V(r,θ)=V(r)+(?²/2Mr²) [(βsin²θ +γcos²θ +λ)/sin θcosθ]² and its exact solutions are presented via the Nikiforov-Uvarov method. The angle dependent part V(θ)=(?²/2Mr²) [(βsin²θ +γcos²θ +λ)/sin θcosθ]², which is reported for the first time embodied the novel angle dependent (NAD) potential and harmonic novel angle dependent potential (HNAD) as special cases. We discuss in detail the effects of the improved ring shaped like potential on the radial parts of the spherical harmonic and Coulomb potentials.
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  Stability of Quark Star Models

  M. Azam, S. A. Mardan, M. A. Rehman

  理论物理通讯. 2016, 65(05): 575-584.

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  In this paper, we investigate the stability of quark stars with four different types of inner matter configurations; isotropic, charged isotropic, anisotropic and charged anisotropic by using the concept of cracking. For this purpose, we have applied local density perturbations technique to the hydrostatic equilibrium equation as well as on physical parameters involved in the model. We conclude that quark stars become potentially unstable when inner matter configuration is changed and electromagnetic field is applied.
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  Second-Order Controllability of Multi-Agent Systems with Multiple Leaders

  刘波, 史运涛, 苏厚胜, 韩潇

  理论物理通讯. 2016, 65(05): 585-592.

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  This paper proposes a new second-order continuous-time multi-agent model and analyzes the controllability of second-order multi-agent system with multiple leaders based on the asymmetric topology. This paper considers the more general case: velocity coupling topology is different from location coupling topology. Some sufficient and necessary conditions are presented for the controllability of the system with multiple leaders. In addition, the paper studies the controllability of the system with velocity damping gain. Simulation results are given to illustrate the correctness of theoretical results.
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  How the X(5568) Challenges Our Understanding of QCD

  郭奉坤, Ulf-G. Meißner, 邹冰松

  理论物理通讯. 2016, 65(05): 593-595.

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  We discuss the X(5568) particle recently announced by the D0 Collaboration. Several types of models were proposed to explain this structure in the literature. As pointed out by Burns and Swanson (arXiv:1603.04366), none of them provides a satisfactory description of the observation. We provide additional arguments using general properties of QCD, and conclude that the observation of the X(5568), if confirmed, poses serious challenges to our understanding of nonperturbative QCD.
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  Room-Temperature Steady-State Entanglement in a Four-Mode Optomechanical System

  王涛, 张锐, 苏雪梅

  理论物理通讯. 2016, 65(05): 596-600.

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  Stationary entanglement in a four-mode optomechanical system, especially under room-temperature, is discussed. In this scheme, when the coupling strengths between the two target modes and the mechanical resonator are equal, the results cannot be explained by the Bogoliubov-mode-based scheme. This is related to the idea of quantum-mechanics-free subspace, which plays an important role when the thermal noise of the mechanical modes is considered. Significantly prominent steady-state entanglement can be available under room-temperature.
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  Synthesis of Two-Color Laser Pulses for the Harmonic Cutoff Extension

  王国利, 周丽华, 赵松峰, 周效信

  理论物理通讯. 2016, 65(05): 601-605.

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  Increasing simultaneously both the cutoff energy and efficiency is a big challenge to all applications of high-order harmonic generation (HHG). For this purpose, the shaping of the waveform of driving pulse is an alternative approach. Here, we show that the harmonic cutoff can be extended by about two times without reducing harmonic yield after considering macroscopic propagation effects, by adopting a practical way to synthesize two-color fields with fixed energy. Our results, combined with the experimental techniques, show the great potential of HHG as a tabletop light source.
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  Nonlinear Dust Acoustic Waves in Dissipative Space Dusty Plasmas with Superthermal Electrons and Nonextensive Ions

  A. M. El-Hanbaly, E. K. El-Shewy, M. Sallah, H. F. Darweesh

  理论物理通讯. 2016, 65(05): 606-612.

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  The nonlinear characteristics of the dust acoustic (DA) waves are studied in a homogeneous, collisionless, unmagnetized, and dissipative dusty plasma composed of negatively charged dusty grains, superthermal electrons, and nonextensive ions. Sagdeev pseudopotential technique has been employed to study the large amplitude DA waves. It (Sagdeev pseudopotential) has an evidence for the existence of compressive and rarefractive solitons. The global features of the phase portrait are investigated to understand the possible types of solutions of the Sagdeev form. On the other hand, the reductive perturbation technique has been used to study small amplitude DA waves and yields the Korteweg-de Vries-Burgers (KdV-Burgers) equation that exhibits both soliton and shock waves. The behavior of the obtained results of both large and small amplitude is investigated graphically in terms of the plasma parameters like dust kinematic viscosity, superthermal and nonextensive parameters.
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  Comparative Study on Two Melting Simulation Methods: Melting Curve of Gold

  刘中利, 孙俊生, 李瑞, 张修路, 蔡灵仓

  理论物理通讯. 2016, 65(05): 613-616.

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  Melting simulation methods are of crucial importance to determining melting temperature of materials efficiently. A high-efficiency melting simulation method saves much simulation time and computational resources. To compare the efficiency of our newly developed shock melting (SM) method with that of the well-established two-phase (TP) method, we calculate the high-pressure melting curve of Au using the two methods based on the optimally selected interatomic potentials. Although we only use 640 atoms to determine the melting temperature of Au in the SM method, the resulting melting curve accords very well with the results from the TP method using much more atoms. Thus, this shows that a much smaller system size in SM method can still achieve a fully converged melting curve compared with the TP method, implying the robustness and efficiency of the SM method.
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  Positron Characteristics in Cadmium and Zinc Chalcogenides

  N. Bouarissa, Z. Rouabah, C. Champion

  理论物理通讯. 2016, 65(05): 617-621.

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  Electron energy levels and positron states have been calculated for cadmium and zinc chalcogenide compounds within the pseudo-potential approach and the independent particle model. Furthermore, the present contribution deals with the electron and positron chemical potentials allowing the calculation of the positron affinity to different materials of interest and hetero-structures formed by these materials. Besides, we here determine the positron diffusion constant by means of the positron deformation potential. An attempt has been made to scale positron affinity and diffusion constant with the lattice constant and the band gap energy, respectively. Such scaling is found to be not possible. The information gathered by the present study is of prime importance for a better understanding of positron trapping at interfaces and precipitates and should be useful in slow positron beam experiments.
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  Quantum Transport through a Triple Quantum Dot System in the Presence of Majorana Bound States

  江兆潭, 曹智远, 仲成成

  理论物理通讯. 2016, 65(05): 622-628.

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  We study the electron transport through a special quantum-dot (QD) structure composed of three QDs and two Majorana bound states (MBSs) using the nonequilibrium Green's function technique. This QD-MBS ring structure includes two channels with the two coupled MBSs being Channel 1 and one QD being Channel 2, and three types of transport processes such as the electron transmission (ET), the Andreev reflection (AR), and the crossed Andreev reflection (CAR). By comparing the ET, AR, and CAR processes through Channels 1 and 2, we make a systematic study on the transport properties of the QD-MBS ring. It is shown that there appear two kinds of characteristic transport patterns for Channels 1 and 2, as well as the interplay between the two patterns. Of particular interest is that there exists an AR-assisted ET process in Channel 2, which is different from that in Channel 1. Thus a clear "X" pattern due to the ET and AR processes appears in the ET, AR, and CAR transmission coefficients. Moreover, we study how Channel 2 affects the three transport processes when Channel 1 is tuned in the ET and CAR regimes. It is shown that the transport properties of the ET, AR and CAR processes can be adjusted by tuning the energy level of the QD embedded in Channel 2. We believe this research should be a helpful reference for understanding the transport properties in the QD-MBS coupled systems.
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  Scanning Tunneling Electron Transport into a Kondo Lattice

  羊富彬, 吴华

  理论物理通讯. 2016, 65(05): 629-634.

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  We theoretically present the results for a scanning tunneling transport between a metallic tip and a Kondo lattice. We calculate the density of states (DOS) and the tunneling current and differential conductance (DC) under different conduction-fermion band hybridization and temperature in the Kondo lattice. It is found that the hybridization strength and temperature give asymmetric coherent peaks in the DOS separated by the Fermi energy. The corresponding current and DC intensity depend on the temperature and quantum interference effect among the c-electron and f-electron states in the Kondo lattice.
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  Influence of In-N Clusters on Band Gap Energy of Dilute Nitride In_xGa_1-xN_yAs_1-y

  赵传阵, 郭恒飞, 陈力颖, 唐春晓, 卢克清

  理论物理通讯. 2016, 65(05): 635-638.

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  The In-N clusters form in the dilute nitride In_xGa_1-xN_yAs_1-y alloys after annealing. It is found that the formation of the In-N clusters not only raises the N levels lying above the conduction band minimum (CBM) of InGaAs, but also raises the N levels below the CBM of InGaAs, leading to the variation of the impurity-host interaction. The blueshift of the band gap energy is relative to the variation of the impurity-host interaction. In order to describe the blueshift of the band gap energy due to the formation of the In-N clusters, a model is developed. It is found that the model can describe the blueshift of the band gap energy well. In addition, it is found the blueshift of the band gap energy due to the atom interdiffusion at the interface can be larger than that due to the formation of the In-N clusters.
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  Effects of Ionic Dependence of DNA Persistence Length on the DNA Condensation at Room Temperature

  毛伟, 刘艳辉, 胡林, 许厚强

  理论物理通讯. 2016, 65(05): 639-644.

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  DNA persistence length is a key parameter for quantitative interpretation of the conformational properties of DNA and related to the bending rigidity of DNA. A series of experiments pointed out that, in the DNA condensation process by multivalent cations, the condensed DNA takes elongated coil or compact globule states and the population of the compact globule states increases with an increase in ionic concentration. At the same time, single molecule experiments carried out in solution with multivalent cations (such as spermidine, spermine) indicated that DNA persistence length strongly depends on the ionic concentration. In order to revolve the effects of ionic concentration dependence of persistence length on DNA condensation, a model including the ionic concentration dependence of persistence length and strong correlation of multivalent cation on DNA is provided. The autocorrelation function of the tangent vectors is found as an effective way to detect the ionic concentration dependence of toroidal conformations. With an increase in ion concentration, the first periodic oscillation contained in the autocorrelation function shifts, the number of segment contained in the first periodic oscillation decreases gradually. According to the experiments, the average long-axis length is defined to estimate the ionic concentration dependence of condensation process further. The relation between long-axis length and ionic concentration matches the experimental results qualitatively.
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  Tachyon Cosmology with Gauss-Bonnet and Non-Minimal Kinetic Couplings

  A. Banijamali

  理论物理通讯. 2016, 65(05): 645-652.

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  We consider a tachyonic model of dark energy in which scalar field non-minimally coupled with curvature and kinetic part of its Lagrangian density. Additionally the model contains the Gauss-Bonnet coupling to the scalar field through an arbitrary function. The non-minimal Gauss-Bonnet coupling function and scalar field potential have been obtained for power-law solution and then for a dynamically varying equation of state. We have extracted the required condition for the so-called phantom divide line crossing in the model and represented such a crossing numerically.
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  Anisotropic Inflationary Scenario Via Generalized Chaplygin Gas Model

  Abdul Jawad, Shamaila Rani

  理论物理通讯. 2016, 65(05): 653-658.

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  We investigate generalized chaplygin gas for warm inflationary scenario in the context of locally rotationally symmetric Bianchi type I universe model. We assume two different cases of dissipative coefficient, i.e., constant as well as function of scalar field. We construct dynamical equations as well as a relationship between scalar and radiation energy densities under slow-roll approximation. We also derive slow-roll parameters, scalar and tensor power spectra, scalar spectral index, tensor to scalar ratio for analyzing inflationary background during high dissipative regime. We also use the WMAP7 data for the discussion of our parameters.