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利用行波解法,研究了考虑交换各向异性和单离子各向异性的一维铁磁链,得出椭圆函数波解和孤子解,并讨论了单离子各向异性对椭圆函数波和孤子的影响.研究表明:单离子各向异性对一维铁磁链中椭圆函数波和孤子的激发及其稳定性有显著影响.单离子各向异性不利于易轴铁磁链中椭圆函数波和孤子解的激发,但有利于它们的稳定;而在易平面铁磁链中,单离子各向异性使椭圆函数波和孤子激发变得容易,但不利于它们的稳定.此外,还讨论了单离子各向异性对一维各向同性铁磁链中的孤子激发具有的影响.
关键词:
各向异性
单离子各向异性
孤子
铁磁链 相似文献
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以一维序参量守恒的反铁磁链为例,采用双子格模型和相干态表示,分析了Aharonov-Bohm磁通对一维反铁磁链中的孤子所产生的影响,结果表明Aharonov-Bohm磁通对孤子的峰值、宽度、静止能量和有效质量均有影响。 相似文献
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谢元栋 《原子与分子物理学报》2007,24(6):1251-1254
求出了一维反铁磁链中双亚格点模型的孤子解,并求出了孤子宽度、峰值、静止能量和有效质量.在al=bl 和al=-bl 两种情况下求方程的精确解. 相似文献
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比较了铁磁单层膜与铁磁/反铁磁双层膜结构中的磁畴演化行为, 发现由于反铁磁层膜对铁磁层膜的耦合作用使得系统的磁畴壁厚度、 磁畴壁等效质量、磁畴壁移动速度等发生了改变, 系统的矫顽场增强, 并出现了交换偏置场. 文章具体研究了反铁磁层耦合作用下其磁畴壁厚度、 等效质量以及磁畴壁移动速度等与反铁磁层的净磁化、 磁各向异性、界面耦合强度以及温度等的关系; 并研究了其对铁磁/反铁磁双层膜中的交换偏置场、矫顽场的影响. 进而 从磁畴结构的形成及其演化上揭示了铁磁/反铁磁双 层膜中出现交换偏置以及矫顽场增加的物理机制. 相似文献
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By using φ-mapping topological current theory and gauge potential decomposition, we discuss the self-dual equation and its solution in the SU(N) Dunne-Jackiw-Pi-Trugenberger model and obtain a new concrete self-dual equation with a δ function. For the SU(3) case, we obtain a new self-duality solution and find the relationship between the soliton solution and topological number which is determined by the Hopf index and Brouwer degree of φ-mapping. In our solution, the flux of this soliton is naturally quantized. 相似文献
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Topological edge solitons represent a significant research topic in the nonlinear topological photonics. They maintain their profiles during propagation, due to the joint action of lattice potential and nonlinearity, and at the same time are immune to defects or disorders, thanks to the topological protection. In the past few years topological edge solitons were reported in systems composed of helical waveguide arrays, in which the time-reversal symmetry is effectively broken. Very recently, topological valley Hall edge solitons have been demonstrated in straight waveguide arrays with the time-reversal symmetry preserved. However, these were scalar solitary structures. Here, for the first time, we report vector valley Hall edge solitons in straight waveguide arrays arranged according to the photonic lattice with innate type-II Dirac cones, which is different from the traditional photonic lattices with type-I Dirac cones such as honeycomb lattice. This comes about because the valley Hall edge state can possess both negative and positive dispersions, which allows the mixing of two different edge states into a vector soliton. Our results not only provide a novel avenue for manipulating topological edge states in the nonlinear regime, but also enlighten relevant research based on the lattices with type-II Dirac cones. 相似文献
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We present a class of exact solutions to the coupled (2+1)-dimensional nonlinear Schrödinger equation with spatially modulated nonlinearity and a special external potential, which describe the evolution of two-component vector solitons in defocusing Kerr-type media. We find a robust soliton solution, constructed with the help of Whittaker functions. For specific choices of the topological charge, the radial mode number and the modulation depth, the solitons may exist in various forms, such as the half-moon, necklace-ring, and sawtooth vortex-ring patterns. Our results show that the profile of such solitons can be effectively controlled by the topological charge, the radial mode number, and the modulation depth. 相似文献
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应用一维相对论电磁粒子模拟程序,研究了线性极化强激光入射到无碰撞密度均匀的次临界密度等离子体中所引起的受激陷俘电子声波散射不稳定性过程.不稳定性的早期行为与是否考虑离子动力学效应无关.当考虑离子动力学效应之后会激发一个随时间增长的离子声波,并且最终由于大振幅电磁孤立子的产生而中断.由于电磁孤立子内的静电场与电磁场所产生的离子加速与俘获效应,导致一个离子涡旋在离子相空间中形成;当电磁孤立子向后加速过程中,若干个离子涡旋结构随之形成.研究发现,离子涡旋结构同样存在于密度不均匀的次临界密度等离子体中.从拓扑的观
关键词:
粒子模拟
受激陷俘电子声波散射
电磁孤立子
离子涡旋 相似文献
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The Skyrme-Faddeev-Niemi (SFN) model, which is an O(3) σ model in three dimensional space, upto fourth-order in the first
derivative is regarded as a low-energy effective theory of SU(2) Yang-Mills theory. One can show from the Wilsonian renormalization
group argument that the effective action of Yang-Mills theory recovers the SFN in the infrared region. However, the theory
contains an additional fourth-order term which destabilizes the soliton solution. In this paper, we derive the second-derivative
term perturbatively and show that the SFN model with the second-derivative term possesses soliton solutions.
Presented at the International Colloquium “Integrable Systems and Quantum Symmetries”, Prague, 16–18 June 2005. 相似文献
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Interaction of in-band and in-gap lattice soliton trains in optically induced two-dimensional photonic lattices
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We demonstrate the coherent interactions of lattice
soliton trains, including in-band solitons (IBSs) and gap soliton
trains (GSTs), in optically induced two-dimensional photonic
lattices with self-defocusing nonlinearity. It is revealed that the
$\pi$-staggered phase structures of the lattice soliton trains will
lead to anomalous interactions. Solely by changing their initial
separations, the transition between attractive and repulsive
interaction forces or reversion of the energy transfer can be
obtained. The `negative refraction' effect of the soliton trains
on the interaction is also discussed. Moreover, two interacting IBSs
can merge into one GST when attraction or energy transfer
happens. 相似文献
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A direct approach has been developed for soliton perturbations based on the Green's function. We first linearized the soliton equation, and then derived the Green's function corresponding to approximation equations of different orders. Finally, we obtained the effects of perturbation on a soliton, namely both the slow time dependence of the soliton parameters and the corrections up to the second-order approximation. The higher-order effects can also be obtained in the same way. 相似文献
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根据光波耦合方程及亮-暗孤子对解,对稳态情况下多束互不相干的光束在有外加电场的双光子非光伏光折变晶体中的传播进行分析,给出产生亮-暗双光子光折变屏蔽光伏孤子族需满足的条件。证明有外加电场双光子非光伏光折变晶体中存在非相干耦合亮-暗混合屏蔽孤子族,孤子族由偏振态和波长都相同的多束互不相干的光形成。当外加电场方向和晶体光轴方向相同时,双光子光折变晶体可支持亮孤子族总峰值光强稍大于暗孤子族总峰值光强的的非相干耦合亮-暗混合孤子族,当外加电场方向与晶体光轴方向相反时,双光子光折变晶体可支持亮孤子族总峰值光强稍小于暗孤子族总峰值光强的非相干耦合亮-暗混合孤子族。 相似文献