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The information storage technology based on anisotropic ferromagnets with sufficiently high magneto-optical effects has received much attention in recent years. The magneto-optical recording combines the merits of magnetic and optical techniques. We investigate the magneto-optical effects on a biquadratic ferromagnet and show that the dynamics of the system is governed by a perturbed nonlinear Schrödinger equation. The evolutions of amplitude and velocity of the soliton are found to be time independent, thereby admitting the lossless propagation of electromagnetic soliton in the medium, which may have potential applications in accordance with the soliton based optical communication systems. We also exploit the role of perturbation, which has a significant impact on the propagation of electromagnetic soliton. 相似文献
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Magnetization dynamics in uniformly magnetized ferromagnetic media is studied by using Landau-Lifshitz-Gilbert equation. The nonlinear evolution equation is integrable with site-dependent and biquadratic exchange interaction by means of Landau-Lifshitz (LL) equation which is well understood. In the present work, we construct the exact solitary solutions of the nonlinear evolution equation, particularly, we employ the modified extended tangent hyperbolic function method. We show the shape changing property of solitons for the given integrable system in the presence of damping as well as inhomogeneities. 相似文献
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《Physics letters. A》2001,278(6):331-338
We study the propagation of electromagnetic wave (EMW) in a linear as well as in a nonlinear anisotropic ferromagnetic medium which are assumed to be free from electric charges by making a nonuniform perturbation analysis. It is found that as the EMW propagates through the linear anisotropic ferromagnetic medium, the magnetic induction and hence the magnetic field component of the EMW are being modulated in the form of solitons. Also, the magnetization of the ferromagnetic medium is excited in the form of solitons. While the magnetic induction soliton is restricted to the plane normal to the direction of propagation, the magnetization excitations are not restricted to any particular plane. Unsaturated nonlinear ferromagnetic media is also found to give similar results. 相似文献
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We study the nonlinear spin dynamics of Heisenberg helimagnet under the effect of electromagnetic wave (EM) propagation. The basic dynamical equation of the spin evolution governed by Landau–Lifshitz equation resembles the director dynamics of the twist in a cholestric liquid crystal. With the use of reductive perturbation technique the perturbation is invoked for the spin magnetization and magnetic field components of the propagating electromagnetic wave. A steady-state solution is derived for the weakly nonlinear regime and for the next order, the components turn around s plane perpendicular to the propagation direction. It is found that as the electromagnetic wave propagates in the medium, both the magnetization and magnetic field modulate in the form of kink soliton modes by introducing amplitude fluctuation in the tail part of the same. 相似文献
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The interaction of bright solitons with impurities in the on-site anisotropy of a ferromagnetic chain is studied. This type of impurities leads to linear and nonlinear perturbing terms in the corresponding nonlinear Schrödinger equation. We have found static soliton-impurity bound states and considered the conditions for their formation. For large values of the anisotropy the character of the impurities is mainly linear. The interaction of propagating solitons with the impurities is also investigated. We have obtained that the solitons can be transmitted, trapped or reflected. The behavior depends on the soliton velocity and width, magnetic parameters and the impurity strength. 相似文献
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Through the example of a uniaxial crystal, it is shown that inverted (negative) refraction of an electromagnetic wave in an anisotropic medium (in contrast to an isotropic medium) may occur even when the spatial dispersion of the dielectric tensor is neglected. 相似文献
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Solving nonlinear evolution partial differential equations has been a longstanding computational challenge. In this paper, we present a universal paradigm of learning the system and extracting patterns from data generated from experiments. Specifically, this framework approximates the latent solution with a deep neural network, which is trained with the constraint of underlying physical laws usually expressed by some equations. In particular, we test the effectiveness of the approach for the Burgers' equation used as an example of second-order nonlinear evolution equations under different initial and boundary conditions. The results also indicate that for soliton solutions, the model training costs significantly less time than other initial conditions. 相似文献
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We propose an effective scheme of the deep learning method for high-order nonlinear soliton equations and explore the influence of activation functions on the calculation results for higher-order nonlinear soliton equations. The physics-informed neural networks approximate the solution of the equation under the conditions of differential operator, initial condition and boundary condition. We apply this method to high-order nonlinear soliton equations, and verify its efficiency by solving the fourth-order Boussinesq equation and the fifth-order Korteweg–de Vries equation. The results show that the deep learning method can be used to solve high-order nonlinear soliton equations and reveal the interaction between solitons. 相似文献
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Summary The theory of diffraction of electromagnetic waves by an ultrasonic wave in a crystal is discussed above. Expressions are obtained for the diffraction field in the near and the far zones. In the near zone the system is shown to be describable by the scattering matrix S of a 2(N+1)-pole, thus enabling the matrix method of network theory to be used for in vestigating different kinds of cascade connection of such systems. The expressions obtained contain the classical formulas of scalar diffraction in an isotropic layer as particular cases.Izvestiya VUZ. Radiofizika, Vol. 9, No. 1, pp. 16–32, 1966 相似文献
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Integrodifferential equations for the cross section of the scatterer and a collocation method are used to obtain a numerical
solution of the problem of scattering of an H-polarized wave by an anisotropic layer of a three-layer dielectric structure.
Zh. Tekh. Fiz. 68, 84–88 (January 1998) 相似文献
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Spatiotemporal evolution of continuous-wave field and dark soliton formation in a microcavity with normal dispersion 下载免费PDF全文
Stable dark soliton and dark pulse formation in normally dispersive and red-detuned microcavities are investigated by numerically solving the normalized Lugiato-Lefever equation. The soliton essence is proved by fitting the calculated field intensity profile with the analytical formula of a dark soliton. Meanwhile, we find that a dark soliton can be generated either from the nonlinear evolution of an optical shock wave or narrowing of a locally broad dark pulse with smoother fronts. Explicit analytical expression is obtained to describe the oscillatory fronts of the optical shock wave. Furthermore,from the calculation results, we show that for smaller frequency detunings, e.g., α 3, in addition to the dark soliton formation, a single dark pulse with an oscillatory dip can also arise and propagate stably in the microcavity under proper pump detuning and pump strength combination. The existence region together with various field intensity profiles and the corresponding spectra of single dark pulse are demonstrated. 相似文献
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This paper studies the propagation of dipole solitons in
highly nonlocal medium by using the variational method. It finds
that the dipole solitons will be stable when the input power obeys a
restrict value. When the incident power does not satisfy the stable
conditions, the nonlocal accessible dipole solitons will undergo
linear harmonic oscillation. It shows such evolution behaviours in
detail. 相似文献