2018年, 第69卷, 第04期　
刊出日期：2018-04-01

  

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  A Super mKdV Equation: Bosonization, Painlevé Property and Exact Solutions

  任博, 楼森岳

  理论物理通讯. 2018, 69(04): 343-346.

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  The symmetry of the fermionic field is obtained by means of the Lax pair of the mKdV equation. A new super mKdV equation is constructed by virtue of the symmetry of the fermionic form. The super mKdV system is changed to a system of coupled bosonic equations with the bosonization approach. The bosonized SmKdV (BSmKdV) equation admits Painlevé property by the standard singularity analysis. The traveling wave solutions of the BSmKdV system are presented by the mapping and deformation method. We also provide other ideas to construct new super integrable systems.
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  On Non-Abelian Extensions of 3-Lie Algebras

  宋丽娜, Abdenacer Makhlouf, 唐荣

  理论物理通讯. 2018, 69(04): 347-356.

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  In this paper, we study non-abelian extensions of 3-Lie algebras through Maurer-Cartan elements. We show that there is a one-to-one correspondence between isomorphism classes of non-abelian extensions of 3-Lie algebras and equivalence classes of Maurer-Cartan elements in a DGLA. The structure of the Leibniz algebra on the space of fundamental objects is also analyzed.
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  Self-Consistent Sources Extensions of Modified Differential-Difference KP Equation

  葛根哈斯, 李雅倩, 张朵朵

  理论物理通讯. 2018, 69(04): 357-366.

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  In this paper, we investigate a modified differential-difference KP equation which is shown to have a continuum limit into the mKP equation. It is also shown that the solution of the modified differential-difference KP equation is related to the solution of the differential-difference KP equation through a Miura transformation. We first present the Grammian solution to the modified differential-difference KP equation, and then produce a coupled modified differential-difference KP system by applying the source generation procedure. The explicit N-soliton solution of the resulting coupled modified differential-difference system is expressed in compact forms by using the Grammian determinant and Casorati determinant. We also construct and solve another form of the self-consistent sources extension of the modified differential-difference KP equation, which constitutes a Bäcklund transformation for the differential-difference KP equation with self-consistent sources.
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  N-fold Darboux Transformation for Integrable Couplings of AKNS Equations

  虞静, 陈守婷, 韩敬伟, 马文秀

  理论物理通讯. 2018, 69(04): 367-374.

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  For the integrable couplings of Ablowitz-Kaup-Newell-Segur (ICAKNS) equations, N-fold Darboux transformation (DT) T_N, which is a 4×4 matrix, is constructed in this paper. Each element of this matrix is expressed by a ratio of the (4N+1)-order determinant and 4N-order determinant of eigenfunctions. By making use of these formulae, the determinant expressions of N-transformed new solutions p^[N], q^[N], r^[N] and s^[N] are generated by this N-fold DT. Furthermore, when the reduced conditions q=-p^* and s=-r^* are chosen, we obtain determinant representations of N-fold DT and N-transformed solutions for the integrable couplings of nonlinear Schrödinger (ICNLS) equations. Starting from the zero seed solutions, one-soliton solutions are explicitly given as an example.
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  Wave Functions for Time-Dependent Dirac Equation under GUP

  张梦瑶, 龙超云, 隆正文

  理论物理通讯. 2018, 69(04): 383-386.

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  In this work, the time-dependent Dirac equation is investigated under generalized uncertainty principle (GUP) framework. It is possible to construct the exact solutions of Dirac equation when the time-dependent potentials satisfied the proper conditions. In(1+1) dimensions, the analytical wave functions of the Dirac equation under GUP have been obtained for the two kinds time-dependent potentials.
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  Phase Properties of Photon-Added Coherent States for Nonharmonic Oscillators in a Nonlinear Kerr Medium

  F. Jahanbakhsh, G. Honarasa

  理论物理通讯. 2018, 69(04): 387-392.

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  The potential of nonharmonic systems has several applications in the field of quantum physics. The photon-added coherent states for annharmonic oscillators in a nonlinear Kerr medium can be used to describe some quantum systems. In this paper, the phase properties of these states including number-phase Wigner distribution function, Pegg-Barnett phase distribution function, number-phase squeezing and number-phase entropic uncertainty relations are investigated. It is found that these states can be considered as the nonclassical states.
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  Proper Conformal Killing Vectors in Kantowski-Sachs Metric

  Tahir Hussain, Muhammad Farhan

  理论物理通讯. 2018, 69(04): 393-398.

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  This paper deals with the existence of proper conformal Killing vectors (CKVs) in Kantowski-Sachs metric. Subject to some integrability conditions, the general form of vector filed generating CKVs and the conformal factor is presented. The integrability conditions are solved generally as well as in some particular cases to show that the non-conformally flat Kantowski-Sachs metric admits two proper CKVs, while it admits a 15-dimensional Lie algebra of CKVs in the case when it becomes conformally flat. The inheriting conformal Killing vectors (ICKVs), which map fluid lines conformally, are also investigated.
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  Repulsive Effect for Unbound High Energy Particles Along Rotation Axis in Kerr-Taub-NUT Spacetime

  张禄, 陈松柏

  理论物理通讯. 2018, 69(04): 399-406.

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  We have investigated the acceleration of the unbound high energy particles moving along the rotation axis in the Kerr-Taub-NUT spacetime, and then study the dependence of the repulsive effects on the NUT charge for the particles in the spacetime. Whether the repulsive effects with the NUT charge become stronger depends on the Carter constant, the position and velocity of the particles themselves. We also present numerically the changes of the observable velocity and acceleration with the NUT charge for the unbound particles in the Kerr-Taub-NUT spacetime.
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  Quasi Three-Body Decay of D Meson

  T. Estabar, H. Mehraban

  理论物理通讯. 2018, 69(04): 407-416.

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  The aim of this work is to provide a phenomenological analysis of the contribution of D⁰ meson to K^*(892)⁰π⁺π^-(K^*(892)⁰→π⁺K^-), K^-π⁺ω (ω→π⁺π-π⁰) and K^-π⁺?(?(1020)→K⁺K^-) quasi-three-body decays. The analysis of mentioned multi-body decays is such as to factorize into the three-body decay and several channels observed. Hadronic three-body decays receive both resonant and non-resonant contribution. Based on the factorization method, there are tree and emission annihilation diagrams for these decay modes. In the case of D⁰ to vector pseudoscalar states appeared in factored terms, the matrix elements of the vector and axial vector currents between the D⁰ and PV mesons can be computed by using D^*+ pole. Considering the non-resonant and resonant amplitude in our computation, the theoretical values of the branching ratio are (9.78±0.46)×10^-3, (2.74±0.17)×10^-2, and (3.53±0.23)×10^-5, while the experimental results of them are (9.9±2.3)×10^-3, (2.7±0.5)×10^-2, and (4±1.7)×10^-5 respectively. Comparing computational analysis values with experimental values show that our results are in approximately agreement with them.
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  Effects of a Weakly Interacting Light U Boson on Protoneutron Stars Including the Hyperon-Hyperon Interactions

  喻孜, 许妍, 张贵清, 胡涛平

  理论物理通讯. 2018, 69(04): 417-424.

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  In the framework of the relativistic mean field theory including the hyperon-hyperon (YY) interactions, protoneutron stars with a weakly interacting light U boson are studied. The U-boson leads to the increase of the star maximum mass. The modification to the maximum mass by the U-boson with the strong YY interaction is larger than that with the weak YY interaction. The maximum mass of the protoneutron star is less sensitive to the U-boson than that of the neutron star. The inclusion of the U-boson narrows down the mass window for the hyperonized protoneutron stars. As g²/μ² increases, the species of hyperons, which can appear in a stable protoneutron star decrease. The rotation frequency, the red shift, the momentum of inertia and the total neutrino fraction of PSR J1903-0327 are sensitive to the U-boson and change with g²/μ² in an approximate linear trend. The possible way to constrain the coupling constants of the U-boson is discussed.
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  Direct Urca Processes Involving Proton ¹S₀ Superfluidity in Neutron Star Cooling

  许妍, 喻孜, 张晓军, 范存波, 刘广洲, 赵恩广, 黄修林, 刘承志

  理论物理通讯. 2018, 69(04): 425-433.

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  A detailed description of the baryon direct Urca processes A:n→p+e+ν_e,B:Λ→p+e+ν_e and C:Ξ^-→Λ+e+ν_e related to the neutron star cooling is given in the relativistic mean field approximation. The contributions of the reactions B and C on the neutrino luminosity are calculated by means of the relativistic expressions of the neutrino energy losses. Our results show that the total neutrino luminosities of the reactions A, B and C within the mass range (1.603--2.067) M_⊙ ((1.515--1.840) M_⊙ for TM1 model) for GM1 model are larger than the corresponding values for neutron star without hyperons. Furthermore, although the neutrino emissivity of the reaction A is suppressed with the appearance of the proton ¹S₀ superfluid,the contribution of the reactions B and C can still quicken a massive neutron star cooling.In particular,the reaction C in PSR J1614-2230 and J0348+0432 is not suppressed by the proton ¹S₀ superfluid due to the higher threshold density of the reaction C,which will further speed up the two pulsars cooling.
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  Controlling Thermal Conduction by Graded Materials

  季钦, 黄吉平

  理论物理通讯. 2018, 69(04): 434-440.

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  Manipulating thermal conductivities are fundamentally important for controlling the conduction of heat at will. Thermal cloaks and concentrators, which have been extensively studied recently, are actually graded materials designed according to coordinate transformation approaches, and their effective thermal conductivity is equal to that of the host medium outside the cloak or concentrator. Here we attempt to investigate a more general problem: what is the effective thermal conductivity of graded materials? In particular, we perform a first-principles approach to the analytic exact results of effective thermal conductivities of materials possessing either power-law or linear gradation profiles. On the other hand, by solving Laplace's equation, we derive a differential equation for calculating the effective thermal conductivity of a material whose thermal conductivity varies along the radius with arbitrary gradation profiles. The two methods agree with each other for both external and internal heat sources, as confirmed by simulation and experiment. This work provides different methods for designing new thermal metamaterials (including thermal cloaks and concentrators), in order to control or manipulate the transfer of heat.
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  Melting Heat in Radiative Flow of Carbon Nanotubes with Homogeneous-Heterogeneous Reactions

  Tasawar Hayat, Khursheed Muhammad, Taseer Muhammad, Ahmed Alsaedi

  理论物理通讯. 2018, 69(04): 441-448.

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  The present article provides mathematical modeling for melting heat and thermal radiation in stagnation-point flow of carbon nanotubes towards a nonlinear stretchable surface of variable thickness. The process of homogeneous-heterogeneous reactions is considered. Diffusion coefficients are considered equal for both reactant and autocatalyst. Water and gasoline oil are taken as base fluids. The conversion of partial differential system to ordinary differential system is done by suitable transformations. Optimal homotopy technique is employed for the solutions development of velocity, temperature, concentration, skin friction and local Nusselt number. Graphical results for various values of pertinent parameters are displayed and discussed. Our results indicate that the skin friction coefficient and local Nusselt number are enhanced for larger values of nanoparticles volume fraction.
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  Numerical Study of Mixed Convective Peristaltic Flow through Vertical Tube with Heat Generation for Moderate Reynolds and Wave Numbers

  Tariq Javed, B. Ahmed, M. Sajid

  理论物理通讯. 2018, 69(04): 449-460.

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  The current study focuses on the numerical investigation of the mixed convective peristaltic mechanism through a vertical tube for non-zero Reynolds and wave number. In the set of constitutional equations, energy equation contains the term representing heat generation parameter. The problem is formulated by dropping the assumption of lubrication theory that turns the model mathematically into a system of the nonlinear partial differential equations. The results of the long wavelength in a creeping flow are deduced from the present analysis. Thus, the current study explores the neglected features of peristaltic heat flow in the mixed convective model by considering moderate values of Reynolds and wave numbers. The finite element based on Galerkin's weighted residual scheme is applied to solve the governing equations. The computed solution is presented in the form of contours of streamlines and isothermal lines, velocity and temperature profiles for variation of different involved parameters. The investigation shows that the strength of circulation for stream function increases by increasing the wave number and Reynolds number. Symmetric isotherms are reported for small values of time-mean flow. Linear behavior of pressure is noticed by vanishing inertial forces while the increase in pressure is observed by amplifying the Reynolds number.
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  Influence of Non-linear Radiation Heat Flux on Rotating Maxwell Fluid over a Deformable Surface: A Numerical Study

  M. Mustafa, A. Mushtaq, T. Hayat, A. Alsaedi

  理论物理通讯. 2018, 69(04): 461-466.

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  Mathematical model for Maxwell fluid flow in rotating frame induced by an isothermal stretching wall is explored numerically. Scale analysis based boundary layer approximations are applied to simplify the conservation relations which are later converted to similar forms via appropriate substitutions. A numerical approach is utilized to derive similarity solutions for broad range of Deborah number. The results predict that velocity distributions are inversely proportional to the stress relaxation time. This outcome is different from that observed for the elastic parameter of second grade fluid. Unlike non-rotating frame, the solution curves are oscillatory decaying functions of similarity variable. As angular velocity enlarges, temperature rises and significant drop in the heat transfer coefficient occurs. We note that the wall slope of temperature has an asymptotically decaying profile against the wall to ambient ratio parameter. From the qualitative view point, temperature ratio parameter and radiation parameter have similar effect on the thermal boundary layer. Furthermore, radiation parameter has a definite role in improving the cooling process of the stretching boundary. A comparative study of current numerical computations and those from the existing studies is also presented in a limiting case. To our knowledge, the phenomenon of non-linear radiation in rotating viscoelastic flow due to linearly stretched plate is just modeled here.
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  Effects of Low Anisotropy on Generalized Ghost Dark Energy in Galileon Gravity

  H. Hossienkhani, V. Fayaz, A. Jafari, H. Yousefi

  理论物理通讯. 2018, 69(04): 467-476.

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  The definition of the Galileon gravity form is extended to the Brans-Dicke theory. Given, the framework of the Galileon theory, the generalized ghost dark energy model in an anisotropic universe is investigated. We study the cosmological implications of this model. In particular, we obtain the equation of state and the deceleration parameters and a differential equation governing the evolution of this dark energy in Bianchi type I model. We also probe observational constraints by using the latest observational data on the generalized ghost dark energy models as the unification of dark matter and dark energy. In order to do so, we focus on observational determinations of the Hubble expansion rate (namely, the expansion history) H(z). As a result, we show the influence of the anisotropy (although low) on the evolution of the universe in the statefinder diagrams for Galileon gravity.