2015年, 第64卷, 第05期　
刊出日期：2015-11-01

  

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  Darboux Transformation for Drinfel'd-Sokolov-Wilson Equation

  牛晓星, 刘青平

  理论物理通讯. 2015, 64(05): 491-494.

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  A coupled system known as the Drinfel'd-Sokolov-Wilson equation is reexamined. With the help of a Lax operator of fourth order, its proper Darboux transformation is constructed. Also, a nonlinear superposition formula is worked out for the associated Bäcklund transformation and some solutions are calculated.
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  Discontinuity and Protection of Quantum Fisher Information for a Two-Qubit System

  王国友, 袁季兵, 曾浩生

  理论物理通讯. 2015, 64(05): 495-500.

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  We analytically investigate the dynamics of quantum Fisher information of two qubits in independent environments for both uncorrelated and entangled input states. Especially, we observe that, in the non-Markovian regime and resonant case, quantum Fisher information of uncorrelated input state vanishes only at discrete time point whereas that of entangled input state can disappear during finite time interval. It shows that quantum Fisher information, which determines the parameter estimation precision, is strongly affected by the environment memory effects, and the advantage of entanglement-enhance metrology no longer exists even for a very short time. We also note that quantum Fisher information for two kinds of input states can be preserved under appropriate qubit-reservoir detuning.
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  Equivalence of a Bit Pixel Image to a Quantum Pixel Image

  Carlos Ortega Laurel, DONG Shi-Hai, M. Cruz-Irisson

  理论物理通讯. 2015, 64(05): 501-506.

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  We propose a new method to transform a pixel image to the corresponding quantum-pixel using a qubit per pixel to represent each pixels classical weight in a quantum image matrix weight. All qubits are linear superposition, changing the coefficients level by level to the entire longitude of the gray scale with respect to the base states of the qubit. Classically, these states are just bytes represented in a binary matrix, having code combinations of 1 or 0 at all pixel locations. This method introduces a qubit-pixel image representation of images captured by classical optoelectronic methods.
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  Analysis on Patterns of Globally Coupled Phase Oscillators with Attractive and Repulsive Interactions

  王鹏飞, 阮晓东, 许忠斌, 付新

  理论物理通讯. 2015, 64(05): 507-514.

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  The Hong-Strogatz (HS) model of globally coupled phase oscillators with attractive and repulsive interactions reflects the fact that each individual (oscillator) has its own attitude (attractive or repulsive) to the same environment (mean field). Previous studies on HS model focused mainly on the stable states on Ott-Antonsen (OA) manifold. In this paper, the eigenvalues of the Jacobi matrix of each fixed point in HS model are explicitly derived, with the aim to understand the local dynamics around each fixed point. Phase transitions are described according to relative population and coupling strength. Besides, the dynamics off OA manifold is studied.
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  Compacton-Like Solutions in a Camassa-Holm Type Equation

  李红, 王侃民, 马立林

  理论物理通讯. 2015, 64(05): 515-518.

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  This paper shows that a Camassa-Holm type equation can be reduced to Hamiltonian system by transformation of variables. The hamiltonian system is studied by making use of the dynamical systems theory and the qualitative behavior of degenerate singular points is presented. In particular, new type of compacton-like solutions is obtained by setting the partial differential equation under boundary condition →±∞ψ(ξ)=A.
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  An Underlying Symmetry Determines all Elements of CKM and PMNS up to a Universal Constant?

  柯红卫, 李学潜

  理论物理通讯. 2015, 64(05): 519-524.

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  Observing the CKM matrix elements written in different parametrization schemes, one can notice obvious relations among the sine-values of the CP phases in those schemes. Using the relations, we establish a few parametrization-independent equations, by which the matrix elements of the CKM matrix can be completely fixed up to a universal parameter. If it is true, we expect that there should exist a hidden symmetry in the nature, which determines the relations. Moreover, it requires a universal parameter, naturally it would be the famous Jarlskog invariant, which is also parametrization independent. Thus the four parameters (three mixing angles and one CP phase) of the CKM matrix are not free, but determined by the symmetry and the universal parameter. As we generalize the rules to the PMNS matrix for neutrino mixing, the CP phase of the lepton sector is predicted to be within a range of 0~59° centered at 39° (in the P_a parametrization) which will be tested in the future experiments.
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  The Role of One Single Lambda Hyperon on Binding Energy Difference of Hypernuclear Mirror Pair

  吕洪凤, 刘玉颖

  理论物理通讯. 2015, 64(05): 525-528.

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  Investigation on isospin symmetry in light Lambda hypernuclei is one of the most important issues in hypernuclear physics. In order to know the influences introduced by a single Lambda hyperon, we study the binding energy difference of mirror hypernuclear pair with mass A=16, 18, 28, 40, and 42 using a time-odd triaxial relativistic mean field theory. Effects as the spin-orbit interaction, the time-odd component of vector fields, the core polarization, the proton-neutron mass difference, and the center-of-mass energy correction are self-consistently considered. Compared to the reported results of ordinary nuclei, the binding energy difference of mirror hypernuclei shows trivial change. With core polarization modified by an impurity hyperon, the isospin nonconserving effect between proton and neutron is hardly reduced for nuclei in study.
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  Propagation of Electron Acoustic Soliton, Periodic and Shock Waves in Dissipative Plasma with a q-Nonextensive Electron Velocity Distribution

  A. M. El-Hanbaly, E. K. El-Shewy, A. Elgarayhi, A. I. Kassem

  理论物理通讯. 2015, 64(05): 529-536.

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  The nonlinear properties of small amplitude electron-acoustic (EA) solitary and shock waves in a homogeneous system of unmagnetized collisionless plasma with nonextensive distribution for hot electrons have been investigated. A reductive perturbation method used to obtain the Kadomstev-Petviashvili-Burgers equation. Bifurcation analysis has been discussed for non-dissipative system in the absence of Burgers term and reveals different classes of the traveling wave solutions. The obtained solutions are related to periodic and soliton waves and their behavior are shown graphically. In the presence of the Burgers term, the EXP-function method is used to solve the Kadomstev-Petviashvili-Burgers equation and the obtained solution is related to shock wave. The obtained results may be helpful in better conception of waves propagation in various space plasma environments as well as in inertial confinement fusion laboratory plasmas.
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  Study of Radially Varying Magnetic Field on Blood Flow through Catheterized Tapered Elastic Artery with Overlapping Stenosis

  S. Nadeem, S. Ijaz

  理论物理通讯. 2015, 64(05): 537-546.

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  A precise model has been developed for studying the influence of metallic nanoparticles on blood flow through catheterized tapered elastic arteries with radially varying magnetic field. The model is solved under the mild stenosis approximation by considering blood as viscous fluid. The influence of different flow parameters associated with this problem such as Hartmann number, nanoparticle volume fraction, Grashof number and heat source or sink parameter is analyzed by plotting the graphs of the wall shear stress, resistance impedance to blood flow and stream lines. The influence of the radially varying magnetic field on resistance impedance to flow is analyzed and it is observed that the significantly strong magnetic force tends to increase in resistance.
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  Mathematical Analysis for Peristaltic Flow of Two Phase Nanofluid in a Curved Channel

  S. Nadeem, Iqra Shahzadi

  理论物理通讯. 2015, 64(05): 547-554.

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  This paper describes the theoretical analysis for peristaltic motion of water base nanofluid containing distinct types of the nanoparticles like Cu, TiO₂, and Al₂O₃. Equations of nano fluid are modelled and simplified by constructing the suppositions of low Reynolds number as well as long wave length. The reduced equations are solved exactly. Solutions are represented through graphs. Outcomes for the velocity, temperature, pressure rise and stream lines are analyzed graphically. The work presented here is based on the fictitious values, however some other values can be tested experimentally.
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  Multi-ion Double Layers in a Magnetized Plasma

  M. Shahmansouri, H. Alinejad, M. Tribeche

  理论物理通讯. 2015, 64(05): 555-564.

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  A theoretical investigation is carried out to study the existence, formation and basic properties of ion acoustic (IA) double layers (DLs) in a magnetized bi-ion plasma consisting of warm/cold ions and Boltzmann distributed electrons. Based on the reductive perturbation technique, an extended Korteweg de-Vries (KdV) equation is derived. The propagation of two possible modes (fast and slow), and their evolution are investigated. The effects of obliqueness, magnitude of the magnetic field, ion concentration, polarity of ions, and ion temperature on the IA DL profile are analyzed, and then the ranges of parameters for which the IA DLs exist are investigated in details.
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  Self-Focusing of Quadruple Gaussian Laser Beam in an Inhomogenous Magnetized Plasma with Ponderomotive Non-Linearity: Effect of Linear Absorption

  Munish Aggarwal, Shivani Vij, Niti Kant

  理论物理通讯. 2015, 64(05): 565-570.

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  The propagation of quadruple Gaussian laser beam in a plasma characterized by axial inhomogeneity and nonlinearity due to ponderomotive force in the paraxial ray approximation is investigated. An appropriate expression for the nonlinear dielectric constant has been developed in the presence of external magnetic field, with linear absorption and due to saturation effects for arbitrary large intensity. The effects of different types of plasma axial inhomogeneities on self-focusing of laser beam have been studied with the typical laser and plasma parameters. Self-focusing of quadruple Gaussian laser beam in the presence of externally applied magnetic field and saturating parameter is found significantly improved in the case of extraordinary mode. Our results reveal that initially converging beam shows oscillatory convergence whereas initially diverging beam shows oscillatory divergence. The beam is more focussed at lower intensity in both cases viz. extraordinary and ordinary mode.
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  Dispersion Properties of High- and Low-Frequency Electrostatic Oscillations of Plasma Spheres: Application to the Metallic Nanoparticles

  Afshin Moradi

  理论物理通讯. 2015, 64(05): 571-575.

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  The dispersion properties of high- and low-frequency electrostatic oscillations of a spherical metallic plasma consisting of hot electrons and cold ions are investigated. The main interest and the key first applications of this system are the spherical metal nanoparticles. General expressions of dispersion relations are obtained for the so-called surface and bulk plasmon waves, and surface and bulk ion-acoustic waves in spherical geometry, using hydrodynamic equations and Poisson equation with appropriate boundary conditions. Numerical results show that dispersion effects become large for metallic particles of small radii, particularly in the range of few nanometers.
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  Acetone Adsorption on Pristine and Pt-doped Graphene: A First-Principles vdW-DF Study

  Masoud Darvish Ganji, Hoda Mazaheri, Azadeh Khosravi

  理论物理通讯. 2015, 64(05): 576-582.

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  Using van der Waals corrected density functional theory (vdW-DF) method we have investigated the adsorption of acetone molecule on pristine and Pt-doped graphene. Several active sites for both the interacting systems have been considered in the adsorption process including full geometry optimization. We have analyzed the structural and electrical properties of energetically favorable configurations. The results show that adsorption of acetone molecule on the Pt-doped graphene is energetically preferable. The binding energy and bonding distance are determined to be -5.277 eV and 2.206 Å, respectively, accompanying with charge transfer of 1.11 e. Furthermore, the Pt-O bond is rather significantly elongated when acetone is adsorbed on Pt-doped graphene. Compared to pristine graphene, the Pt-doped graphene has stronger interaction with the acetone and may provide more sensitive signal for a single acetone molecule. Meanwhile, practically, the band gap of Pt-doped graphene would become reduced after acetone adsorption. Consequently, our first-principles study presents evidence for a coherent benchmark for the applicability of Pt-doped graphene for acetone adsorption and detection.
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  Electronic Correlation Effects on the Optical Properties of SiC, BeO and Boron Nitride Nanotubes and Monolayers

  H. Rezania, Z. Aghaii Manesh

  理论物理通讯. 2015, 64(05): 583-589.

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  We present numerical calculation of the impact of electron-electron interaction on the behavior of density of states and optical properties of BeO, SiC and Boron-Nitride nanotubes and sheets. Hubbard model hamiltonian is applied to describe the dynamics of electrons on the lattice structure of theses compounds. The excitation spectrum of the system in the presence of local electronic interactions has been found using mean field approach. We find the band gap width in both optical absorption and density of states reduces with local Hubbard electronic interaction parameter. The absorption spectra exhibits the remarkable peaks, mainly owing to the divergence behavior of density of states and excitonic effects. Also we compare optical absorption frequency behavior of BeO, SiC and Boron-Nitride nanotubes with each other. Furthermore we investigate the optical properties of BeO and SiC sheets. A novel feature of optical conductivity of these structures is the decrease of frequency gap in the optical spectrum due to electronic interaction.
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  Generalized Ghost Pilgrim Scalar Field Models of Dark Energy

  Abdul Jawad, Ujjal Debnath, Fazal Batool

  理论物理通讯. 2015, 64(05): 590-596.

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  We assume generalized ghost Pilgrim dark energy (GGPDE) model in the presence of cold dark matter in flat FRW universe. With suitable choice of interaction term between GGPDE and cold dark matter, we investigate the nature of equation of state parameter for GGPDE. Also, we investigate the natures of dynamical scalar field models (such as quintessence, tachyon, k-essence, and dilaton dark energy) and concerned potentials through the correspondence phenomenon between GGPDE and these models.
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  Generalized Second Law of Thermodynamics in Parabolic LTB Inhomogeneous Cosmology

  A. Sheykhi, H. Moradpour, K. Rezazadeh Sarab, B. Wang

  理论物理通讯. 2015, 64(05): 597-604.

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  We study thermodynamics of the parabolic Lemaitre-Tolman-Bondi (LTB) cosmology supported by a perfect fluid source. This model is the natural generalization of the flat Friedmann-Robertson-Walker (FRW) universe, and describes an inhomogeneous universe with spherical symmetry. After reviewing some basic equations in the parabolic LTB cosmology, we obtain a relation for the deceleration parameter in this model. We also obtain a condition for which the universe undergoes an accelerating phase at the present time. We use the first law of thermodynamics on the apparent horizon together with the Einstein field equations to get a relation for the apparent horizon entropy in LTB cosmology. We find out that in LTB model of cosmology, the apparent horizon's entropy could be feeded by a term, which incorporates the effects of the inhomogeneity. We consider this result and get a relation for the total entropy evolution, which is used to examine the generalized second law of thermodynamics for an accelerating universe. We also verify the validity of the second law and the generalized second law of thermodynamics for a universe filled with some kinds of matters bounded by the event horizon in the framework of the parabolic LTB model.