2012年, 第58卷, 第04期　
刊出日期：2012-10-15

  

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  Integrable Deformations of the (2+1)-Dimensional Heisenberg Ferromagnetic Model

  颜昭雯, 陈敏茹, 吴可, 赵伟忠

  理论物理通讯. 2012, 58(04): 463-468.

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  Based on the covariant prolongation structure technique,we construct the integrable higher-order deformations of the (2+1)-dimensional Heisenberg ferromagnet model and obtain their su(2)×R(λ) prolongation structures.By associating these deformed multidimensional Heisenberg ferromagnet models with the moving space curve in Euclidean space and using the Hasimoto function,we derive their geometrical equivalent counterparts,i.e.,higher-order (2+1)-dimensional nonlinear Schrödinger equations.
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  A Finite Genus Solution of the Veselov's Discrete Neumann System

  曹策问, 许晓雪

  理论物理通讯. 2012, 58(04): 469-474.

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  The Veselov's discrete Neumann system is derived through nonlinearization of a discrete spectral problem.Based on the commutative relation between the Lax matrix and the Darboux matrix with finite genus potentials,a special solution is calculated with the help of the Baker-Akhiezer-Kriechever function.
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  The Quasi-Periodic Solutions for the Variable-Coefficient KdV Equation

  欧阳凤娇, 邓淑芳

  理论物理通讯. 2012, 58(04): 475-479.

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  Hirota method is used to directly construct quasi-periodic wave solutions for the nonisospectral soliton equation.One and two quasi-periodic wave solutions for the variable-coefficient KdV equation are studied.The well known one-soliton solution can be reduced from the one quasi-periodic wave solution.
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  Virial Theorem for a Class of Quantum Nonlinear Harmonic Oscillators

  王雪红, 郭军义, 李艳

  理论物理通讯. 2012, 58(04): 480-482.

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  In this paper,the Virial Theorem based on a class of quantum nonlinear harmonic oscillators is presented.This relationship has to do with parameter λ and ∂/∂λ,where the λ is a real number.When λ=0,the nonlinear harmonic oscillator naturally reduces to the usual quantum linear harmonic oscillator,and the Virial Theorem also reduces to the usual Virial Theorem.
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  Some Properties of D-Concurrence

  韦娜娜, 李愿

  理论物理通讯. 2012, 58(04): 483-486.

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  In this note,we give a new lower bound for the concurrence,which is related to D-concurrence.For the Werner states,we compare that this D-concurrence bound with the other known bound.In addition,some of new upper and lower bounds of D-concurrence are given.
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  Lower Bounds on the Capacities of Quantum Relay Channels

  石金晶, 施荣华, 彭小奇, 郭迎, 易留洋, 李门浩

  理论物理通讯. 2012, 58(04): 487-492.

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  Robust Generation of Three-Particle W State with Atoms Trapped in Separate Cavities

  辛斌, 贾仁需, 郑亦庄

  理论物理通讯. 2012, 58(04): 493-496.

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  This paper presents a scheme for generating three-particle W state of remote atoms trapped in leaky cavities.The scheme uses cavity decay to inject photons into a setup of optical devices which consist of a series of beam splitters and photon detectors.Photon detection on the output mode projects the atomic state into the W state.In the condition of “weakly driven approach”,it shows that the scheme is robust and has high fidelity.It also points out that the scheme is scalable to generate multi-atomic W state.
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  Investigation of PT-symmetric Hamiltonian Systems from an Alternative Point of View

  李军青, 李倩, 缪炎刚

  理论物理通讯. 2012, 58(04): 497-503.

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  Two non-Hermitian PT-symmetric Hamiltonian systems are reconsidered by means of the algebraic method which was originally proposed for the pseudo-Hermitian Hamiltonian systems rather than for the PT-symmetric ones.Compared with the way converting a non-Hermitian Hamiltonian to its Hermitian counterpart,this method has the merit that keeps the Hilbert space of the non-Hermitian PT-symmetric Hamiltonian unchanged.In order to give the positive definite inner product for the PT-symmetric systems,a new operator V,instead of C,can be introduced.The operator V has the similar function to the operator C adopted normally in the PT-symmetric quantum mechanics,however,it can be constructed,as an advantage,directly in terms of Hamiltonians.The spectra of the two non-Hermitian PT-symmetric systems are obtained,which coincide with that given in literature,and in particular,the Hilbert spaces associated with positive definite inner products are worked out.
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  Improved Canonical Quantization Method of Self Dual Field

  樊丰华, 黄永畅

  理论物理通讯. 2012, 58(04): 504-508.

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  In this paper,the improved canonical quantization method of the self dual field is given in order to overcome linear combination problem about the second class constraint and the first class constraint number maximization problem in the Dirac method.In the improved canonical quantization method,there are no artificial linear combination and the first class constraint number maximization problems,at the same time,the stability of the system is considered.Therefore,the improved canonical quantization method is more natural and easier accepted by people than the usual Dirac method.We use the improved canonical quantization method to realize the canonical quantization of the self dual field,which has relation with string theory successfully and the results are equal to the results by using the Dirac method.
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  Entropy Spectrum of Black Holes of Heterotic String Theory via Adiabatic Invariance

  Alexis Larrañaga, Luis Cabarique, Manuel Londoño

  理论物理通讯. 2012, 58(04): 509-512.

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  Using adiabatic invariance and the Bohr-Sommerfeld quantization rule we investigate the entropy spectroscopy of two black holes of heterotic string theory,the charged GMGHS and the rotating Sen solutions.It is shown that the entropy spectrum is equally spaced in both cases,identically to the spectrum obtained before for Schwarzschild,Reissner-Nordström and Kerr black holes.Since the adiabatic invariance method does not use quasinormal mode analysis,there is no need to impose the small charge or small angular momentum limits and there is no confusion on whether the real part or the imaginary part of the modes is responsible for the entropy spectrum.
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  Hawking Radiation of a Kaluza-Klein Black Hole Described by Landauer Transport Model

  兰小刚, 韦联福

  理论物理通讯. 2012, 58(04): 513-516.

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  We investigate the Hawking radiation of a Kaluza-Klein black hole by using one-dimensional(1D),non-equilibrium,Landauer transport model.The derived Hawking radiation temperature is in consistence with that obtained by using the usual anomaly method.With the Landauer transport model,we calculate the entropy flow out of the Kaluza-Klein black hole and the relevant entropy production rate.How these quantities depending on the physical parameters of the black hole is also discussed.
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  Entropy Quantization from a Neutral Black String

  方戈亮

  理论物理通讯. 2012, 58(04): 517-519.

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  Taking into account the Bekenstein-Hawking area law,based on the analysis of Zeng and Liu et al.that area spectrum is determined by the periodicity of an outgoing wave,we discuss on the quantization of entropy from a neutral black string.In addition,applying the adiabatic invariant quantity method proposed by Majhi and Vagenas,we further verify the entropy quantum of the neutral black string.As a result,two different methods show that the quantum of entropy is Δ S=2π,which is in agreement with Bekenstein's proposal.
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  A Novel Bit-level Image Encryption Method Based on Chaotic Map and Dynamic Grouping

  张国基, 沈彦

  理论物理通讯. 2012, 58(04): 520-524.

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  In this paper,a novel bit-level image encryption method based on dynamic grouping is proposed.In the proposed method,the plain-image is divided into several groups randomly,then permutation-diffusion process on bit level is carried out.The keystream generated by logistic map is related to the plain-image,which confuses the relationship between the plain-image and the cipher-image.The computer simulation results of statistical analysis,information entropy analysis and sensitivity analysis show that the proposed encryption method is secure and reliable enough to be used for communication application.
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  Impulsive Cluster Synchronization in Community Network with Nonidentical Nodes

  邓丽萍, 吴召艳

  理论物理通讯. 2012, 58(04): 525-530.

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  In this paper,cluster synchronization in community network with nonidentical nodes and impulsive effects is investigated.Community networks with two kinds of topological structure are investigated.Positive weighted network is considered first and external pinning controllers are designed for achieving cluster synchronization.Cooperative and competitive network under some assumptions is investigated as well and can achieve cluster synchronization with only impulsive controllers.Based on the stability analysis of impulsive differential equation and the Lyapunov stability theory,several simple and useful synchronization criteria are derived.Finally,numerical simulations are provided to verify the effectiveness of the derived results.
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  Rogue Waves of the Higher-Order Dispersive Nonlinear Schrödinger Equation

  王晓丽, 张卫国, 翟保国, 张海强

  理论物理通讯. 2012, 58(04): 531-538.

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  In this paper,the rogue waves of the higher-order dispersive nonlinear Schrödinger (HDNLS) equation are investigated,which describes the propagation of ultrashort optical pulse in optical fibers.The rogue wave solutions of HDNLS equation are constructed by using the modified Darboux transformation method.The explicit first and second-order rogue wave solutions are presented under the plane wave seeding solution background.The nonlinear dynamics and properties of rogue waves are discussed by analyzing the obtained rational solutions.The influence of little perturbation ε on the rogue waves is discussed with the help of graphical simulation.
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  The Limit of Noether Conserved Charges is the Number of Primary First-Class Constraints in a Constrained System

  王永龙, 吴朝霞, 潘洪哲, 卢伟涛, 蒋华, 陈丽

  理论物理通讯. 2012, 58(04): 539-543.

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  We discuss the stationarity of generator G for gauge symmetries in two directions.One is to the motion equations defined by total Hamiltonian H_T,and gives that the number of the independent coefficients in the generator G is not greater than the number of the primary first-class constraints,and the number of Noether conserved charges is not greater than that of the primary first-class constraints,too.The other is to the variances of canonical variables deduced from the generator G,and gives the variances of Lagrangian multipliers contained in extended Hamiltonian H_E.And a second-class constraint generated by a first-class constraint may imply a new first-class constraint which can be combined by introducing other second-class constraints.Finally,we supply two examples.One with three first-class constraints (two is primary and one is secondary) has two Noether conserved charges,and the secondary first-class constraint is combined by three second-class constraints which are a secondary and two primary second-class constraints.The other with two first-class constraints (one is primary and one is secondary) has one Noehter conserved charge.
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  Ground State Properties of Ds Isotopes Within the Relativistic Mean Field Theory

  张海飞, 张鸿飞, 李君清

  理论物理通讯. 2012, 58(04): 544-550.

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  The ground state properties of Ds (Z=110) isotopes (N=151-195) are studied in the framework of the relativistic mean field (RMF) theory with the effective interaction NL-Z2.The pairing correlation is treated within the conventional BCS approximation.The calculated binding energies are consistent with the results from finite-range droplet model (FRDM) and Macroscopic-microscopic method (MMM).The quadrupole deformation,α-decay energy,α-decay half-live,charge radius,two-neutron separation energy and single-particle spectra are analyzed for Ds isotopes to find new characteristics of superheavy nuclei (SHN).Among the calculated results it is rather distinct that the isotopic shift appears evidently at neutron number N=184.
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  Optomechanical Dark State in a Dual-Species Bose-Einstein Condensate

  景辉, D. S. Goldbaum

  理论物理通讯. 2012, 58(04): 551-556.

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  We study cavity optomechanics of ultracold dual-species atomic mixtures with nonlinear collisions.Interspecies interactions provide a direct parametric coupling of fictitious mechanical elements which,through interfering with the intracavity optical field,leads to a switchable optically-dark state for either species.This demonstrates a matter-wave analog of recently observed mechanical wave mixing and quantum motional-state swapping,with applications in the construction of integrated phononic devices,and the cavity-enhanced detection of quantum degenerate atomic mixtures.
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  Extension of Harmonic Cutoff and Generation of Isolated Sub-30 as Pulse in a Two-Color Chirped Laser Field

  张刚台, 白婷婷, 张美光

  理论物理通讯. 2012, 58(04): 557-564.

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  We theoretically investigate high-order harmonic and isolated attosecond pulse generation in a two-color chirped laser field,which is synthesized by a 9 fs/800 nm fundamental chirped pulse and a 9 fs/1600 nm controlling chirped pulse.Our numerical results show that,by using this method,not only is the harmonic cutoff significantly extended to the 948th order harmonic,but also the bandwidth of the supercontinuum spectrum is effectively broadened to about 1342 eV.In addition,due to the introduction of the chirp,the long quantum path is suppressed and only the short one is selected,and then an isolated 28 as pulse with a bandwidth of 155 eV is obtained directly.
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  An Exact Solution to the Two-Particle Boltzmann Equation System for Maxwell Gases

  Burenmandula, 赵迎春

  理论物理通讯. 2012, 58(04): 565-568.

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  An exact solution to the two-particle Boltzmann equation system for Maxwell gases is obtained with use of Bobylev approach.The relationship between the exact solution and the self-similar solution of the boltzmann equation is also given.
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  Effects of Relativistic and Ponderomotive Nonlinearities on an Intense Laser Pulse Propagation in a Plasma Channel

  刘明萍, 郑振, 刘三秋, 戴伟华, 刘杰

  理论物理通讯. 2012, 58(04): 569-572.

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  The optical guiding of a moderately intense laser pulse in a parabolic preformed plasma channel is analyzed by means of the variational method.Relativistic,ponderomotive and their coupling nonlinearities are included.The conditions for periodic defocusing and focusing,as well as constant spot size propagation are given.It is found that the laser focusing is released by the coupling of relativistic and ponderomotive nonlinearities.
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  Pauli Paramagnetic Susceptibility of an Ideal Anyon Gas within Haldane Fractional Exclusion Statistics

  覃昉, 陈继胜

  理论物理通讯. 2012, 58(04): 573-576.

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  The finite-temperature Pauli paramagnetic susceptibility of a three-dimensional ideal anyon gas obeying Haldane fractional exclusion statistics is studied analytically.Different from the result of an ideal Fermi gas,the susceptibility of an ideal anyon gas depends on a statistical factor g in Haldane statistics model.The low-temperature and high-temperature behaviors of the susceptibility are investigated in detail.The Pauli paramagnetic susceptibility of the two-dimensional ideal anyons is also derived.It is found that the reciprocal of the susceptibility has the similar factorizable property which is exhibited in some thermodynamic quantities in two dimensions.
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  Surface Passivation of Ti/4H-SiC Schottky Barrier Diode

  Muhammad Khalid, Saira Riaz, Shahzad Naseem

  理论物理通讯. 2012, 58(04): 577-582.

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  Surface properties of SiC power devices mostly depend on the passivation layer (PL).This layer has direct influence on electrical characteristics of devices.2D numerical simulation of forward and reverse characteristics with and without different (PLs) (SiO₂,HfO₂ and Si₃N₄) has been performed.Simulation results show that the breakdown voltage increases with increasing PL thickness,and there is a lesser significant effect on forward characteristics.The maximum breakdown voltage with and without SiO₂ PL is 1240 V and 276 V,respectively.SiO₂ PL has compatibility with SiC surface providing high breakdown voltage,6 and 8% higher than that of HfO₂ and Si₃N₄ respectively.Low leakage current is observed which then further decreases on reducing the thickness of PL.Furthermore,variation of forward current with dielectric constant and thickness of PLs was observed.Finally,it is suggested that matches of our results with published experimental results indicate that the Sentaurus TCAD simulator is a predictive tool for the SiC Schottky barrier diode simulation.
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  A Stochastic LWR Model with Consideration of the Driver's Individual Property

  唐铁桥, 王云鹏, 余贵珍, 黄海军

  理论物理通讯. 2012, 58(04): 583-589.

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  In this paper,we develop a stochastic LWR model based on the influences of the driver's individual property on his/her perceived density and speed deviation.The numerical results show that the driver's individual property has great effects on traffic flow only when the initial density is moderate,i.e.,at this time,oscillating traffic flow will occur and the oscillating phenomena in the traffic system consisting of the conservative and aggressive drivers is more serious than that in the traffic system consisting of the conservative (aggressive) drivers.
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  Impact of the Next-Nearest-Neighbor Interaction on Traffic Flow of Highway with Slopes

  李志鹏, 周盈

  理论物理通讯. 2012, 58(04): 590-598.

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  In this paper,we study the motion course of traffic flow on the slopes of a highway by applying a microscopic traffic model,which takes into account the next-nearest-neighbor interaction in an intelligent transportation system environment.Three common gradients of the highway,which are sag terrain,uphill terrain,and downhill terrain on a single-lane roadway,are selected to clarify the impact on the traffic flow by the next-nearest-neighbor interaction in relative velocity.We obtain the current-density relation for traffic flow on the sag,the uphill and the downhill under the next-nearest-neighbor interaction strategy.It is observed that the current saturates when the density is greater than a critical value and the current decreases when the density is greater than another critical value.When the density falls into the intermediate range between the two critical densities it is also found that the oscillatory jam,easily leads to traffic accidents,often appears in the downhill stage,and the next-nearest-neighbor interaction in relative velocity has a strong suppressing effect on this kind of dangerous congestion.A theoretical analysis is also presented to explain this important conclusion.
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  Modeling Dynamic Evolution of Online Friendship Network

  吴联仁, 闫强

  理论物理通讯. 2012, 58(04): 599-603.

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  In this paper,we study the dynamic evolution of friendship network in SNS (Social Networking Site).Our analysis suggests that an individual joining a community depends not only on the number of friends he or she has within the community,but also on the friendship network generated by those friends.In addition,we propose a model which is based on two processes:first,connecting nearest neighbors;second,strength driven attachment mechanism.The model reflects two facts:first,in the social network it is a universal phenomenon that two nodes are connected when they have at least one common neighbor;second,new nodes connect more likely to nodes which have larger weights and interactions,a phenomenon called strength driven attachment (also called weight driven attachment).From the simulation results,we find that degree distribution P(k),strength distribution P(s),and degree-strength correlation are all consistent with empirical data.
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  Feature Analysis and Modeling of the Network Community Structure

  袁超, 柴毅, 魏善碧

  理论物理通讯. 2012, 58(04): 604-612.

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  Community structure has an important influence on the structural and dynamic characteristics of the complex systems.So it has attracted a large number of researchers.However,due to its complexity,the mechanism of action of the community structure is still not clear to this day.In this paper,some features of the community structure have been discussed.And a constraint model of the community has been deduced.This model is effective to identify the communities.And especially,it is effective to identify the overlapping nodes between the communities.Then a community detection algorithm,which has linear time complexity,is proposed based on this constraint model,a proposed node similarity model and the Modularity Q.Through some experiments on a series of real-world and synthetic networks,the high performances of the algorithm and the constraint model have been illustrated.
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  Beyond the Friedmann-Lemaâtre-Robertson-Walker Big Bang Singularity

  Cristi Stoica

  理论物理通讯. 2012, 58(04): 613-616.

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  Einstein's equation,in its standard form,breaks down at the Big Bang singularity.A new version,equivalent to Einstein's whenever the latter is defined,but applicable in wider situations,is proposed.The new equation remains smooth at the Big Bang singularity of the Friedmann-Lemaâtre-Robertson-Walker model.It is a tensor equation defined in terms of the Ricci part of the Riemann curvature.It is obtained by taking the Kulkarni-Nomizu product between Einstein's equation and the metric tensor.