完整力学系统的高阶运动微分方程

从质点系的牛顿动力学方程出发,引入系统的高阶速度能量,导出完整力学系统的高阶Lagrange方程、高阶Nielsen方程以及高阶Appell方程,并证明了完整系统三种形式的高阶运动微分方程是等价的.结果表明,完整系统高阶运动微分方程揭示了系统运动状态的改变与力的各阶变化率之间的联系,这是牛顿动力学方程以及传统分析力学方程不能直接反映的.因此,完整系统高阶运动微分方程是对牛顿动力学方程及传统Lagrange方程、Nielsen方程、Appell方程等二阶运动微分方程的进一步补充. 关键词： 高阶速度能量 高阶Lagrange方程 高阶 Nielsen方程 高阶Appell方程     

高阶效应影响下高阶孤子在超常介质中的传输特性研究

基于描述超短脉冲在超常介质中传输的非线性薛定谔方程,本文数值研究了高阶效应影响下高阶亮、暗孤子在超常介质中的传输情况。数值模拟表明,三阶色散和自陡峭效应都会引起高阶孤子的分裂和辐射,破坏高阶亮孤子周期性演化特性,导致高阶暗孤子分裂出的灰孤子不对称;孤子的阶数越高,三阶色散和自陡峭的影响越大。利用超常介质可控的色散和非线性特性,通过调节三阶色散和自陡峭效应的系数,发现超常介质中可以基本支持二阶亮孤子、二阶暗孤子和三阶暗孤子的稳定演化。本文的研究结果为将来进一步研究超常介质中高阶亮、暗孤子的存在及传输特性提供了一定的参考价值。     

Higher-Order Lagrangian Equations of Higher-Order Motive Mechanical System

In this paper, if the condition of variation δt=0 is satisfied, the higher-order Lagrangian equations and higher-order Hamilton's equations, which show the consistency with the results of traditional analytical mechanics, are obtained from the higher-order Lagrangian equations and higher-order Hamilton's equations. The results can enrich the theory of analytical mechanics.     

Higher-order squeezing of quantum field and higher-order uncertainty relations in non-degenerate four-wave mixing

It is found that the field of the combined mode of the probe wave and the phase conjugate wave in the process of non-degenerate four-wave mixing exhibits higher-order squeezing to all even orders. The higher-order squeezed parameter and squeezed limit due to the modulation frequency are investigated. The smaller the modulation frequency is, the stronger the degree of higher-order squeezing becomes. Furthermore, the higher-order uncertainty relations in the process of non-degenerate four-wave mixing are presented for the first time. The product of higher-order noise moments is related to even order number N and the length L of the medium.     

Higher-order squeezing of quantum electromagnetic fields and higher-order uncertainty relations in two-mode squeezed states

It is found that the two-mode output quantum electromagnetic field in two-mode squeezed states exhibits higherorder squeezing to all even orders, and the degree of higher-order squeezing is greater than that of the second-order.The higher-order squeezed parameter and squeezed limit due to the modulation frequency are investigated. The smaller the modulation frequency is, the stronger the degree of higher-order squeezing becomes. Furthermore, the higher-order uncertainty relations in two-mode squeezed states are presented for the first time. The product of higher-order noise moments is related to even order number N and the squeeze factor r.     

Higher-order differential variational principle and differential equations of motion for mechanical systems in event space

In this paper we study the higher-order differential variational principle and differential equations of motion for mechanical systems in event space. Based on the higher-order d＇Alembert principle of the system, the higher-order velocity energy and the higher-order acceleration energy of the system in event space are defined, the higher-order d＇Alembert- Lagrange principle of the system in event space is established, and the parametric forms of Euler-Lagrange, Nielsen and Appell for this principle are given. Finally, the higher-order differential equations of motion for holonomic systems in event space are obtained.     

Topological invariants for anomalous Floquet higher-order topological insulators

We review the recent development in constructing higher-order topological band insulators under strong periodic drivings. In particular, we focus on various approaches in formulating the anomalous Floquet topological invariants beyond (quasi-)static band topology, and compare their different physical consequences.     

高阶效应对自相似抛物线脉冲相互作用的影响

讨论高阶效应对自相似抛物线脉冲传输中相互作用的影响.数值研究结果证明高阶效应使得自相似抛物线脉冲形状畸变非常严重,并加剧脉冲间的相互作用.我们分析了不同的高阶效应对脉冲间相互作用的具体影响.而且我们可通过幅度调制和脉冲压缩技术,获得较高质量的自相似抛物线脉冲串传输.这些结果对进一步研究高质量的自相似抛物线脉冲在高功率超短脉冲光纤放大器、激光器和传输系统中的应用有重要的意义.     

Higher-order solitons in amplitude-disordered waveguide arrays

We investigate the existence and stability of different families of spatial solitons in optical waveguide arrays whose amplitudes obey a disordered distribution. The competition between focusing nonlinearity and linearly disordered refractive index modulation results in the formation of spatial localized nonlinear states. Solitons originating from Anderson modes with few nodes are robust during propagation. While multi-peaked solitons with in-phase neighboring components are completely unstable, multipole-mode solitons whose neighboring components are out-of-phase can propagate stably in wide parameter regions provided that their power exceeds a critical value. Our findings, thus, provide the first example of stable higher-order nonlinear states in disordered systems.     

吸收材料对超导高频腔高次模抑制的实验研究

束流粒子通过加速腔的基模加速,以达到所需的能量值. 由于腔本身的多谐性,束流在超导腔里面会激发起高次模,其中其电场分布对粒子加速起到负面作用的,称之谓有害高次模,减小或抑制有害高次模是加速腔研究的一个重要环节,利用铝模型腔对超导腔的高次模抑制进行研究,给出测量结果,研究表明:铁氧体是很好的微波吸收材料,对于所研究的超导腔内的高次模有着良好的吸收效果.     

Symmetries in a Constrained System with a Singular Higher-Order Lagrangian

A simple algorithm to construct the generator of gauge transformation for a constrained canonical system with a singular higher-order Lagrangian in field theories is developed. Based on phase-space generating functional of Green function for such a system, the generalized canonical Ward identities under the non-local transformation have been deduced. For the gauge-invariant system, based on configuration-space generating functional, the generalized Ward identities under the non-local transformation have been also derived.The conservation laws are deduced at the quantum level. The applications of the above results to the gauge invariance massive vector field and non-Abelian Chern–Simons(CS) theories with higher-order derivatives are given, a new form of gauge-ghost proper vertices, and Ward–Takahashi identity under BRS transformation and BRS charge at the quantum level are obtained. In the canonical formulation one does not need to carry out the integration over canonical momenta in phase-space path integral as usually performed.     

Tunneling dynamics of Bose-Einstein condensates with higher-order interactions in optical lattice

The nonlinear Landau-Zener tunneling and nonlinear Rabi oscillations of Bose-Einstein condensate (BEC) with higher-order atomic interaction between the Bloch bands in an accelerating optical lattice are discussed. Within the two-level model, the tunneling probability of BEC with higher-order atomic interaction between Bloch bands is obtained. We finds that the tunneling rate is closely related to the higher-order atomic interaction. Furthermore, the nonlinear Rabi oscillations of BEC with higher-order atomic interaction between the bands are discussed by imposing a periodic modulation on the level bias. Analytical expressions of the critical higher-order atomic interaction for suppressing/enhancing the Rabi oscillations are obtained. It is shown that the critical value strongly depends on the modulation parameters (i.e., the modulation amplitude and frequency) and the strength of periodic potential.     

Bose-Einstein Condensates in Optical Lattices with Higher-Order Interactions

The higher-order interactions of Bose-Einstein condensate in multi-dimensional optical lattices are discussed both analytically and numerically.It is demonstrated that the effects of the higher-order atomic interactions on the sound speed and the stabilities of Bloch waves strongly depend on the lattice strength.In the presence of higher-order effects,tighter and high-dimensional lattices are confirmed to be two positive factors for maintaining the system's energetic stability,and the dynamical instability of Bloch waves can take place simultaneously with the energetic instability.In addition,we find that the higher-order interactions exhibit a long-range behavior and the long-lived coherent Bloch oscillations in a tilted optical lattice exist.Our results provide an effective way to probe the higher-order interactions in optical lattices.     

High-order perturbed corrections with scaling transformation

The performance of the so-called superconvergent quantum perturbation theory （Wenhua Hal et al2000 Phys. Rev. A 61 052105） is investigated for the case of the ground-state energy of the helium-like ions. The scaling transformation τ → τ/Z applied to the Hamiltonian of a two-electron atomic ion with a nuclear charge Z （in atomic units）. Using the improved Rayleigh-SchrSdinger perturbation theory based on the integral equation to helium-like ions in the ground states and treating the electron correlations as perturbations, we have performed a third-order perturbation calculation and obtained the second-order corrected wavefunctions consisting of a few terms and third-order energy corrections. We find that third-order and higher-order energy corrections are improved with decreasing nuclear charge. This result means that the former is quadratically integrable and the latter is physically meaningful. The improved quantum perturbation theory fits the higher-order perturbation case. This work shows that it is a development on the quantum perturbation problem of helium-like systems.     

Theoretical Investigations of Third-Order Dispersion Term on Relative Intensity Noise for Dispersive Optical Communication System

In this article we present improved theoretical investigations into relative intensity noise (RIN), including the impact of a third-order dispersion term for dispervive optical communication systems. It has been shown that the third-order dispersion term has no impact on RIN even at high noise frequencies as reported by other authors, but with second-order dispersion compensation, the RIN can be dramatically reduced, thereby improving overall system performance. Further, the impact of fiber length and laser linewidth has been investigated for RIN. It has been shown that, as the fiber length increases, the value of RIN increases but the improvement over RIN with second-order dispersion compensation decreases. Also, with decrease in the value of linewidth, the RIN can be reduced to a great extent.     

Higher-order corrected Higgs bosons in FeynHiggs2.4

Large higher-order corrections enter the Higgs boson sector of the MSSM via Higgs-boson self-energies. Their effects have to be taken into account for the correct treatment of loop-corrected Higgs-boson mass eigenstates as external (on-shell) or internal particles in Feynman diagrams. We review how the loop corrections, including momentum dependence and imaginary contributions, are correctly taken into account for external (on-shell) Higgs boson and how effective couplings can be derived. The procedures are implemented in the code FeynHiggs2.4.      

Propagation of bright femtosecond pulses in a nonlinear optical fibre with the third- and fourth-order dispersions

We solve the generalized nonlinear Schr\"{o}dinger equation describing the propagation of femtosecond pulses in a nonlinear optical fibre with higher-order dispersions by using the direct approach to perturbation for bright solitons, and discuss the combined effects of the third- and fourth-order dispersions on velocity, temporal intensity distribution and peak intensity of femtosecond pulses. It is noticeable that the combined effects of the third- and fourth-order dispersions on an initial propagated soliton can partially compensate each other, which seems to be significant for the stability controlling of soliton propagation features.     

Higher-order nonclassical effects generated by multiple-photon annihilation-then-creation and creation-then-annihilation coherent states

We explore two observable nonclassical properties of quantum states generated by repeatedly operating annihilationthen-creation(AC) and creation-then-annihilation(CA) on the coherent state, respectively, such as higher-order subPoissonian statistics and higher-order squeezing-enhanced effect. The corresponding analytical expressions are derived in detail depending on m. By numerically comparing those quantum properties, it is found that these states above have very different nonclassical properties and nonclassicality is exhibited more strongly after AC operation than after CA operation.     

基于高阶统计量双相干理论的图像篡改识别算法

随着图像处理技术的快速地发展和广泛地应用,图像篡改变得越来越容易和普及.恶意篡改的图像会对新闻、司法等领域造成极大的负面影响.对基于高阶统计量双相干理论的图像篡改检测方法进行了深入研究,论述了该方法的原理,并应用该方法进行了大量的分类真假图像对照实验,分析了该方法的适用条件和局限性,实验结果表明,该方法的识别准确率与拼...