共查询到20条相似文献,搜索用时 0 毫秒
1.
By using the traditional perturbation method, we obtain the nonlinear Sehrodinger equation for one-dimensional Schrodinger-Poisson system. Some of its solutions can explain previous results. 相似文献
2.
The wave packets, both linear and nonlinear (like solitons) signals described by a complex time-dependent function, are mapped onto positive probability distributions (tomograms). The quasidistributions, wavelets, and tomograms are shown to have an intrinsic connection. The analysis is extended to signals obeying to the von Neumann-like equation. For solitons (nonlinear signals) obeying the nonlinear Schrödinger equation, the tomographic probability representation is introduced. It is shown that in the probability representation the soliton satisfies a nonlinear generalization of the Fokker–Planck equation. Solutions to the Gross–Pitaevskii equation corresponding to solitons in a Bose–Einstein condensate are considered. 相似文献
3.
To study the nonlinear phenomena in rod-like magnetic liquid crystals (RMLCs), this paper establishes the dynamic model of molecular motion when giving a twisting disturbance to the molecules under external magnetic field. We find the twist of the molecules under magnetic field can be propagated in the form of a traveling wave. The dynamic equation of the molecular twisting we derived satisfies the form of Sine-Gordon equation. We obtain two solutions of the Sine-Gordon equation by theoretical calculation: the kink and anti-kink solitons and breathers. The characteristics of those solitons and breathers are discussed. 相似文献
4.
5.
飞秒暗孤子间相互作用的数值研究 总被引:7,自引:1,他引:6
通过数值模拟对飞秒暗孤子间的相互作用进行了研究,并且同飞秒亮孤子和皮秒暗孤子分别进行了比较,结果表明:同飞秒亮孤子相比,飞秒暗孤子间的相互作用比较小,前者表现为相互吸引、碰撞、合二为一,然后相互排斥,不具有周期性;而后者从一开始就相互排斥,且这种排斥作用较亮孤子来说相当微弱,同样也不具有周期性。此外,数值模拟的结果还表明,飞秒暗孤子间的相互作用同皮秒尺度下暗孤子间的相互作用基本一致,并且通过计算表明,飞秒暗孤子间的相互作用在一定范围内仍可利用皮秒尺度下暗孤子间相互作用的经验公式。但是,数值模拟结果显示,两孤子的初始间距越小,由经验公式计算结果所带来的误差就越大。 相似文献
6.
Charis Anastopoulos 《Foundations of Physics》2006,36(11):1601-1661
We demonstrate in this paper that the probabilities for sequential measurements have features very different from those of single-time measurements. First, they cannot be modelled by a classical stochastic process. Second, they are contextual, namely they depend strongly on the specific measurement scheme through which they are determined. We construct Positive-Operator-Valued measures (POVM) that provide such probabilities. For observables with continuous spectrum, the constructed POVMs depend strongly on the resolution of the measurement device, a conclusion that persists even if we consider a quantum mechanical measurement device or the presence of an environment. We then examine the same issues in alternative interpretations of quantum theory. We first show that multi-time probabilities cannot be naturally defined in terms of a frequency operator. We next prove that local hidden variable theories cannot reproduce the predictions of quantum theory for sequential measurements, even when the degrees of freedom of the measuring apparatus are taken into account. Bohmian mechanics, however, does not fall in this category. We finally examine an alternative proposal that sequential measurements can be modeled by a process that does not satisfy the Kolmogorov axioms of probability. This removes contextuality without introducing non-locality, but implies that the empirical probabilities cannot be always defined (the event frequencies do not converge). We argue that the predictions of this hypothesis are not ruled out by existing experimental results (examining in particular the “which way” experiments); they are, however, distinguishable in principle. 相似文献
7.
一维光伏空间灰孤子及其稳定性研究 总被引:4,自引:2,他引:2
从考虑背景光的光伏作用后的光束在光伏媒质中传播的方程出发,证明了在折射率改变为正的光伏媒质中也可以形成灰孤子。光束以灰孤子状态在光伏晶体中传播时,其横向相位必须具有一个与光强分布有关的形式分布,表达式为φ(s)=v[η-∫y^-2(η)dη],其中v是灰孤子的横向运动速度,η是无量纲化坐标,y(η)是归一化的光场振幅。分别讨论了光束灰度、光强振幅、信号光与背景光的有效Glass系数之比R对一维的光伏空间灰孤子宽度、横向总相移和横向运动速度的影响,并分析了光伏灰孤子的稳定性。当光束的灰度m为0时,这一理论可直接退化为光伏暗孤子的理论。 相似文献
8.
In a recent paper, a “distance” function,
, was defined which measures the distance between pure classical and quantum systems. In this work, we present a new definition of a “distance”, D, which measures the distance between either pure or impure classical and quantum states. We also compare the new distance formula with the previous formula, when the latter is applicable. To illustrate these distances, we have used 2 × 2 matrix examples and two-dimensional vectors for simplicity and clarity. Several specific examples are calculated. 相似文献
9.
In this Letter we study the sine-Gordon and the Liouville hierarchies in laboratory coordinates from a bi-Hamiltonian point
of view. Besides the well-known local structure these hierarchies possess a second compatible nonlocal Poisson structure. 相似文献
10.
MA Song-Hua QIANG Ji-Ye FANG Jian-Ping 《理论物理通讯》2007,48(4):662-666
By means of an improved mapping method and a variable separation method, a series of variable separation solutions including solitary wave solutions, periodic wave solutions and rational function solutions) to the (2+1)-dimensional breaking soliton system is derived. Based on the derived solitary wave excitation, we obtain some special annihilation solitons and chaotic solitons in this short note. 相似文献
11.
A nonlinear electrodynamics Lagrangian is considered and the electric field associated to an electric point-like charge is
derived. The corresponding expression for the total field energy which has finite value in our model, is obtained. The chiral
form of the Lagrangian is also presented. Topological, finite-energy, spherically symmetric solutions of the chiral model
are studied and some of their properties are discussed. 相似文献
12.
Peter Lynds 《Foundations of Physics Letters》2003,16(4):343-355
It is postulated there is not a precise static instant in time underlying a dynamical physical process at which the relative position of a body in relative motion or a specific physical magnitude would theoretically be precisely determined. It is concluded it is exactly because of this that time (relative interval as indicated by a clock) and the continuity of a physical process is possible, with there being a necessary trade off of all precisely determined physical values at a time, for their continuity through time. This explanation is also shown to be the correct solution to the motion and infinity paradoxes, excluding the Stadium, originally conceived by the ancient Greek mathematician Zeno of Elea. Quantum Cosmology, Imaginary Time and Chronons are also then discussed, with the latter two appearing to be superseded on a theoretical basis. 相似文献
13.
Thierry Dauxois Nikos Theodorakopoulos Michel Peyrard 《Journal of statistical physics》2002,107(3-4):869-891
Many thermodynamic instabilities in one dimension (e.g., DNA thermal denaturation, wetting of interfaces) can be described in terms of simple models involving harmonic coupling between nearest neighbors and an asymmetric on-site potential with a repulsive core, a stable minimum and a flat top. The paper deals with the case of the Morse on-site potential, which can be treated exactly in the continuum limit. Analytical expressions for correlation functions are derived; they are shown to obey scaling; numerical transfer-integral values obtained for a discrete version of the model exhibit the same critical behavior. Furthermore, it is shown in detail that the onset of the transition can be characterized by an entropic stabilization of an—otherwise unstable—nonlinear field configuration, a soliton-like domain wall (DW) with macroscopic energy content. The statistical mechanics of the DW provides an exact estimate of the critical temperature for a wide range of the discretization parameter; this suggests that the transition can be accurately viewed as being driven by a nonlinear entity. 相似文献
14.
From the unified statistical thermodynamics of quantum gases, the virial coefficients of ideal Bose and Fermi gases, trapped under generic power law potential are derived systematically. From the general result of virial coefficients, one can produce the known results in d=3 and d=2. But more importantly we found that, the virial coefficients of Bose and Fermi gases become identical (except the second virial coefficient, where the sign is different) when the gases are trapped under harmonic potential in d=1. This result suggests the equivalence between Bose and Fermi gases established in d=1 (J. Stat. Phys. DOI 10.1007/s10955-015-1344-4). Also, it is found that the virial coefficients of two-dimensional free Bose (Fermi) gas are equal to the virial coefficients of one-dimensional harmonically trapped Bose (Fermi) gas. 相似文献
15.
16.
双芯耦合光纤中高阶色散对光孤子相互作用的影响 总被引:3,自引:0,他引:3
利用变分原理对耦合纤芯中传输光孤子之间的相互作用和形成束缚孤子态的条件进行了研究,发现高阶色散减弱甚至可以消除光孤子之间的相互作用。这一结果为耦合光纤器件的设计提供了一种实用消除光孤子之间相互作用的方法。 相似文献
17.
在矩形域[-a,a]×[-a,a]内对微分算子L=(ə2)/(əx2)+(ə2)/(əy2)用5点差分格式将二维非定常Sine Gordon方程离散化为一个2×7992阶非线性Hamilton系统.对该系统使用Euler中心格式,得到一个非线性方程组.对此方程组建立迭代解法并给出了这个迭代方法的收敛条件和收敛速度.Sine Gordon方程单孤子和双孤子的数值模拟试验显示该辛算法是有效的. 相似文献
18.
The formation and propagation of shocks and solitons are investigated in anunmagnetized, ultradense plasma containing degenerate Fermi gas of electrons and positrons, and classical ion gas by employing Thomas-Fermi model. For this purpose, a deformed Korteweg-de Vries-Berger (dKdVB) equation is derived using the reductive perturbative technique for cold, adiabatic, and isothermal ions. Localized analytical solutions of dKdVB equation in planar geometry are obtained for dispersion as well as dissipation dominant cases. For nonplanar (cylindrical and spherical) geometry, time varying numerical shock wave solution of dKdVB equation is found. Its dispersion dominant case leading to the soliton solution is also discussed. The effect of ion temperature, positron concentration and dissipation is found significant on these nonlinear structures. The relevance of the results to the systems of scientific interest is pointed out. 相似文献
19.
Anjan Biswas 《International Journal of Theoretical Physics》2009,48(1):256-260
This paper obtains the 1-soliton solution of the nonlinear Schr?dinger’s equation with Kerr law nonlinearity and time-dependent
dispersion, nonlinearity and attenuation. The solitary wave ansatze is used to obtain this solution. The constraint relation
between these time-dependent coefficients is also obtained for the solitons to exist. The variation of the soliton velocity
also falls out by this method. 相似文献
20.
In this letter, we prove that non-trivial compact Yamabe solitons or breathers do not exist. In particular our proof in the
two dimensional case depends only on properties of the determimant of the Laplacian and turns out to be independent of the
classical uniformization theorem (UT). Using this remarkable fact we are able to explain how an independent proof of the UT
for Riemann surfaces can be obtained using the Yamabe–Ricci flow.
Luca Fabrizio Di Cerbo was partially supported by a Renaissance Technology Fellowship. 相似文献