2018年, 第69卷, 第01期　
刊出日期：2018-01-01

  

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  Density-Dependent Conformable Space-time Fractional Diffusion-Reaction Equation and Its Exact Solutions

  Kamyar Hosseini, Peyman Mayeli, Ahmet Bekir, Ozkan Guner

  理论物理通讯. 2018, 69(01): 1-4.

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  In this article, a special type of fractional differential equations (FDEs) named the density-dependent conformable fractional diffusion-reaction (DDCFDR) equation is studied. Aforementioned equation has a significant role in the modelling of some phenomena arising in the applied science. The well-organized methods, including the exp (-φ (ε))-expansion and modified Kudryashov methods are exerted to generate the exact solutions of this equation such that some of the solutions are new and have been reported for the first time. Results illustrate that both methods have a great performance in handling the DDCFDR equation.
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  Group Analysis, Fractional Explicit Solutions and Conservation Laws of Time Fractional Generalized Burgers Equation

  王岗伟, A. H. Kara

  理论物理通讯. 2018, 69(01): 5-8.

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  The generalized fractional Burgers equation is studied in this paper. Using the classical Lie symmetry method, all of the vector fields and symmetry reduction of the equation with nonlinearity are constructed. In particular, an exact solution is provided by using the ansatz method. In addition, other types of exact solution are obtained via the invariant subspace method. Finally, conservation laws for this equation are derived.
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  On Superintegrable Systems with a Cubic Integral of Motion

  尚琳, 黄晴

  理论物理通讯. 2018, 69(01): 9-13.

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  We present a variety of superintegrable systems in polar coordinates possessing a cubic and a quadratic integral of motion, where Noether integrals of kinetic energy are used to build the integrals. In addition, the associated polynomial Poisson algebras with their algebraic dependence relations are exhibited.
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  A Direct Algorithm Maple Package of One-Dimensional Optimal System for Group Invariant Solutions

  张琳, 韩众, 陈勇

  理论物理通讯. 2018, 69(01): 14-22.

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  To construct the one-dimensional optimal system of finite dimensional Lie algebra automatically, we develop a new Maple package One Optimal System. Meanwhile, we propose a new method to calculate the adjoint transformation matrix and find all the invariants of Lie algebra in spite of Killing form checking possible constraints of each classification. Besides, a new conception called invariance set is raised. Moreover, this Maple package is proved to be more efficiency and precise than before by applying it to some classic examples.
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  Comparative Effect of an Addition of a Surface Term to Woods-Saxon Potential on Thermodynamics of a Nucleon

  B. C. Lütfüoğlu

  理论物理通讯. 2018, 69(01): 23-27.

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  In this study, we reveal the difference between Woods-Saxon (WS) and Generalized Symmetric Woods-Saxon (GSWS) potentials in order to describe the physical properties of a nucleon, by means of solving Schrödinger equation for the two potentials. The additional term squeezes the WS potential well, which leads an upward shift in the spectrum, resulting in a more realistic picture. The resulting GSWS potential does not merely accommodate extra quasi bound states, but also has modified bound state spectrum. As an application, we apply the formalism to a real problem, an α particle confined in Bohrium-270 nucleus. The thermodynamic functions Helmholtz energy, entropy, internal energy, specific heat of the system are calculated and compared for both wells. The internal energy and the specific heat capacity increase as a result of upward shift in the spectrum. The shift of the Helmholtz free energy is a direct consequence of the shift of the spectrum. The entropy decreases because of a decrement in the number of available states.
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  Note on Resonant and Non-resonant Peaks in Electron-Atom Total Scattering Cross Sections

  Karl-Erik Thylwe, Patrick McCabe

  理论物理通讯. 2018, 69(01): 28-30.

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  Certain broad low-energy peaks caused by a single partial wave in total cross sections are explained in terms of phase shifts. Such peaks have been associated with the real part of a Regge pole trajectory, having a maximum near an integer value of the angular momentum quantum number. At the peak energies, the pertinent partial-wave phase shift was shown to have a local maximum near a value π/2 modulo π. This implies no time delay in the semiclassical context. The phenomenon is a quantum effect, lacking a semiclassical interpretation.
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  A Quantum Private Query Protocol for Enhancing both User and Database Privacy

  周艺华, 白雪玮, 黎雷蕾, 侍伟敏, 杨宇光

  理论物理通讯. 2018, 69(01): 31-36.

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  In order to protect the privacy of query user and database, some QKD-based quantum private query (QPQ) protocols were proposed. Unfortunately some of them cannot resist internal attack from database perfectly; some others can ensure better user privacy but require a reduction of database privacy. In this paper, a novel two-way QPQ protocol is proposed to ensure the privacy of both sides of communication. In our protocol, user makes initial quantum states and derives the key bit by comparing initial quantum state and outcome state returned from database by ctrl or shift mode instead of announcing two non-orthogonal qubits as others which may leak part secret information. In this way, not only the privacy of database be ensured but also user privacy is strengthened. Furthermore, our protocol can also realize the security of loss-tolerance, cheat-sensitive, and resisting JM attack etc.
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  Atomic Interferometric Gravitational-Wave Space Observatory (AIGSO)

  高东峰, 王谨, 詹明生

  理论物理通讯. 2018, 69(01): 37-42.

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  We propose a space-borne gravitational-wave detection scheme, called atom interferometric gravitational-wave space observatory (AIGSO). It is motivated by the progress in the atomic matter-wave interferometry, which solely utilizes the standing light waves to split, deflect and recombine the atomic beam. Our scheme consists of three drag-free satellites orbiting the Earth. The phase shift of AIGSO is dominated by the Sagnac effect of gravitational-waves, which is proportional to the area enclosed by the atom interferometer, the frequency and amplitude of gravitational-waves. The scheme has a strain sensitivity < 10^-20/√Hz in the 100 mHz-10 Hz frequency range, which fills in the detection gap between space-based and ground-based laser interferometric detectors. Thus, our proposed AIGSO can be a good complementary detection scheme to the space-borne laser interferometric schemes, such as LISA. Considering the current status of relevant technology readiness, we expect our AIGSO to be a promising candidate for the future space-based gravitational-wave detection plan.
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  Electromagnetic Coupling of Negative Parity Nucleon Resonances N (1535) Based on Nonrelativistic Constituent Quark Model

  Sara Parsaei, Ali Akbar Rajabi

  理论物理通讯. 2018, 69(01): 43-49.

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  The electromagnetic transition between the nucleon and excited baryons has long been recognized as an important source of information for understanding strong interactions in the domain of quark confinement. We study the electromagnetic properties of the excitation of the negative parity the N^*(1535) resonances in the nonrelativistic constituent quark model at large momentum transfers and have performed a calculation the longitudinal and transverse helicity amplitudes. Since the helicity amplitudes depend strongly on the quark wave function in this paper, we consider the baryon as a simple, non-relativistically three-body quark model and also consider a hypercentral potential scheme for the internal baryon structure, which makes three-body forces among three quarks. Since the hyper central potential depends only on the hyper radius, therefore, the Cornell potential which is a combination of the Coulombic-like term plus a linear confining term is considered as the potential for interaction between quarks. In our work, in solving the Schrodinger equation with the Cornell potential, the Nikiforov-Uvarov method employed, and the analytic eigen-energies and eigen-functions obtained. By using the obtained eigen-functions, the transition amplitudes calculated. We show that our results in the range Q² > 2 GeV² lead to an overall better agreement with the experimental data in comparison with the other three non-relativistic quark models.
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  A Study of ρ-ω Mixing in Resonance Chiral Theory

  陈云华, 姚德良, 郑汉青

  理论物理通讯. 2018, 69(01): 50-58.

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  The strong and electromagnetic corrections to ρ-ω mixing are calculated using an SU(2) version of resonance chiral theory up to next-to-leading orders in 1/N_C expansion, respectively. Up to our accuracy, the effect of the momentum dependence of ρ-ω mixing is incorporated due to the inclusion of loop contributions. We analyze the impact of ρ-ω mixing on the pion vector form factor by performing numerical fit to the data extracted from e⁺e^-→π⁺π^- and τ→ν_τ2π, while the decay width of ω→ π⁺π^- is taken into account as a constraint. It is found that the momentum dependence is significant in a good description of the experimental data. In addition, based on the fitted values of the involved parameters, we analyze the decay width of ω → π⁺π^-, which turns out to be highly dominated by the ρ-ω mixing effect.
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  Spatial Dependent Spontaneous Emission of an Atom in a Semi-Infinite Waveguide of Rectangular Cross Section

  宋海希, 孙晓祺, 卢竞, 周兰

  理论物理通讯. 2018, 69(01): 59-67.

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  We study a quantum electrodynamics (QED) system made of a two-level atom and a semi-infinite rectangular waveguide, which behaves as a perfect mirror in one end. The spatial dependence of the atomic spontaneous emission has been included in the coupling strength relevant to the eigenmodes of the waveguide. The role of retardation is studied for the atomic transition frequency far away from the cutoff frequencies. The atom-mirror distance introduces different phases and retardation times into the dynamics of the atom interacting resonantly with the corresponding transverse modes. It is found that the upper state population decreases from its initial as long as the atom-mirror distance does not vanish, and is lowered and lowered when more and more transverse modes are resonant with the atom. The atomic spontaneous emission can be either suppressed or enhanced by adjusting the atomic location for short retardation time. There are partial revivals and collapses due to the photon reabsorbed and re-emitted by the atom for long retardation time.
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  Unique Outcomes of Internal Heat Generation and Thermal Deposition on Viscous Dissipative Transport of Viscoplastic Fluid over a Riga-Plate

  Z. Iqbal, Ehtsham Azhar, Zaffar Mehmood, E. N. Maraj

  理论物理通讯. 2018, 69(01): 68-76.

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  Boundary layer stagnation point flow of Casson fluid over a Riga plate of variable thickness is investigated in present article. Riga plate is an electromagnetic actuator consists of enduring magnets and gyrated aligned array of alternating electrodes mounted on a plane surface. Physical problem is modeled and simplified under appropriate transformations. Effects of thermal radiation and viscous dissipation are incorporated. These differential equations are solved by Keller Box Scheme using MATLAB. Comparison is given with shooting techniques along with Range-Kutta Fehlberg method of order 5. Graphical and tabulated analysis is drawn. The results reveal that Eckert number, radiation and fluid parameters enhance temperature whereas they contribute in lowering rate of heat transfer. The numerical outcomes of present analysis depicts that Keller Box Method is capable and consistent to solve proposed nonlinear problem with high accuracy.
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  Discrete Boltzmann Method with Maxwell-Type Boundary Condition for Slip Flow

  张玉东, 许爱国, 张广财, 陈志华

  理论物理通讯. 2018, 69(01): 77-85.

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  The rarefied effect of gas flow in microchannel is significant and cannot be well described by traditional hydrodynamic models. It has been known that discrete Boltzmann model (DBM) has the potential to investigate flows in a relatively wider range of Knudsen number because of its intrinsic kinetic nature inherited from Boltzmann equation. It is crucial to have a proper kinetic boundary condition for DBM to capture the velocity slip and the flow characteristics in the Knudsen layer. In this paper, we present a DBM combined with Maxwell-type boundary condition model for slip flow. The tangential momentum accommodation coefficient is introduced to implement a gas-surface interaction model. Both the velocity slip and the Knudsen layer under various Knudsen numbers and accommodation coefficients can be well described. Two kinds of slip flows, including Couette flow and Poiseuille flow, are simulated to verify the model. To dynamically compare results from different models, the relation between the definition of Knudsen number in hard sphere model and that in BGK model is clarified.
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  Electron Acceleration by Beating of Two Intense Cross-Focused Hollow Gaussian Laser Beams in Plasma

  Saleh T. Mahmoud, Rakhi Gauniyal, Nafis Ahmad, Priyanka Rawat, Gunjan Purohit

  理论物理通讯. 2018, 69(01): 86-94.

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  This paper presents propagation of two cross-focused intense hollow Gaussian laser beams (HGBs) in collisionless plasma and its effect on the generation of electron plasma wave (EPW) and electron acceleration process, when relativistic and ponderomotive nonlinearities are simultaneously operative. Nonlinear differential equations have been set up for beamwidth of laser beams, power of generated EPW, and energy gain by electrons using WKB and paraxial approximations. Numerical simulations have been carried out to investigate the effect of typical laser-plasma parameters on the focusing of laser beams in plasmas and further its effect on power of excited EPW and acceleration of electrons. It is observed that focusing of two laser beams in plasma increases for higher order of hollow Gaussian beams, which significantly enhanced the power of generated EPW and energy gain. The amplitude of EPW and energy gain by electrons is found to enhance with an increase in the intensity of laser beams and plasma density. This study will be useful to plasma beat wave accelerator and in other applications requiring multiple laser beams.
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  Simultaneous Effects of Impurity and Electric Field on Entropy Behavior in Double Cone-Like Quantum Dot

  R. Khordad, H. R. Rastegar Sedehi, H. Bahramiyan

  理论物理通讯. 2018, 69(01): 95-100.

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  In this work, the simultaneous effects of electric field and impurity on the non-extensive entropy of a GaAs/Ga_0.5In_0.5As double cone-like quantum dot that is grown on a GaAs wet layer are studied. The system is under an external electric field directed along the -x direction. First, we have solved the Schrödinger equation using the finite element method. Then, we have used the Tsallis formalism and calculated the entropy of the system for different temperatures, electric fields and impurity locations. It is found that the entropy decreases with increasing the electric field and temperature. Since the electric field directed along the -x direction, the entropy reduces when the impurity moves toward the left hand side.
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  Ti Impurity Effect on the Optical Coefficients in 2D Cu₂Si: A DFT Study

  Bromand Nourozi, Arash Boochani, Ahmad Abdolmaleki, Elmira Sartpi, Pezhman Darabi, Sirvan Naderi

  理论物理通讯. 2018, 69(01): 101-106.

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  The electronic and optical properties of 2D Cu₂Si and Cu₂Si:Ti are investigated based on the density functional theory (DFT) using the FP-LAPW method and GGA approximation. The 2D Cu₂Si has metallic and non magnetic properties, whereas adding Ti impurity to its structure changes the electronic behavior to the half-metallic with 3.256 μ_B magnetic moment. The optical transition is not occurred in the infrared and visible area for the 2D Cu₂Si in x-direction and by adding Ti atom, the real part of dielectric function in the x-direction, Re(ε(ω))_x is reached to a Dirac peak at this energy range. Moreover, the absorption gap tends to zero in x-direction of the 2D Cu₂Si:Ti.
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  Solitary Potential in a Space Plasma Containing Dynamical Heavy Ions and Bi-Kappa Distributed Electrons of Two Distinct Temperatures

  M. Sarker, B. Hosen, M. R. Hossen, A. A. Mamun

  理论物理通讯. 2018, 69(01): 107-114.

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  The heavy ion-acoustic solitary waves (HIASWs) in a magnetized, collisionless, space plasma system (containing dynamical heavy ions and bi-kappa distributed electrons of two distinct temperatures) have been theoretically investigated. The Korteweg-de Vries (K-dV), modified K-dV (MK-dV), and higher-order MK-dV (HMK-dV) equations are derived by employing the reductive perturbation method. The basic features of HIASWs (viz. speed, polarity, amplitude, width, etc.) are found to be significantly modified by the effects of number density and temperature of different plasma species, and external magnetic field (obliqueness). The K-dV and HM-KdV equations give rise to both compressive and rarefactive solitary structures, whereas the MK-dV equation supports only the compressive solitary structures. The implication of our results in some space and laboratory plasma situations are briefly discussed.