共查询到20条相似文献,搜索用时 109 毫秒
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We conduct an experimental investigation of nonlinearity management in optics using femtosecond pulses and layered Kerr media consisting of glass and air. By examining the propagation properties over several diffraction lengths, we show that wave collapse can be prevented. We corroborate these experimental results with numerical simulations of the (2+1)-dimensional focusing cubic nonlinear Schr?dinger equation with piecewise constant coefficients and a theoretical analysis of this setting using a moment method. 相似文献
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C. Q. Dai Y. J. Xu R. P. Chen S. Q. Zhu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,59(3):457-461
By means of the similarity transformation, we obtain exact bright
and dark similariton-pair solutions in nonlinear waveguides for
the generalized nonlinear Schr?dinger equation exhibiting
spatial inhomogeneity, inhomogeneous nonlinearity and gain or loss
at the same time. Then we investigate the interaction behaviors of
these solitonic similaritons in a periodic distributed
amplification system. 相似文献
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We develop an averaging method for solitons of the nonlinear Schr?dinger equation with a periodically varying nonlinearity coefficient, which is used to effectively describe solitons in Bose-Einstein condensates, in the context of the recently proposed technique of Feshbach resonance management. Using the derived local averaged equation, we study matter-wave bright and dark solitons and demonstrate a very good agreement between solutions of the averaged and full equations. 相似文献
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The formation and propagation of dipole domains in superlattices are studied both by the modified discrete drift model and by the nonlinear schroedinger equation,the spatiotemporal distribution of the electric field and electron density are presented.The numerical results are compared with the soliton solutions of the nonlinear Schroedinger equation and analysed.It is shown that the numerical solutions agree with the soliton solutions of the nonlinear Schroedinger equation.The dipole electric-field domains in semiconductor superlattices have the properties of solitons. 相似文献
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Frequency-resolved optical gating is used to characterize the propagation of intense femtosecond pulses in a nonlinear, dispersive medium. The combined effects of diffraction, normal dispersion, and cubic nonlinearity lead to pulse splitting. The role of the phase of the input pulse is studied. The results are compared with the predictions of a three-dimensional nonlinear Schr?dinger equation. 相似文献
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By using the solutions of an auxiliary elliptic equation, a direct algebraic method is proposed to construct the exact solutions of nonlinear Schrfdinger type equations. It is shown that many exact periodic solutions of some nonlinear Schro^edinger type equations are explicitly obtained with the aid of symbolic computation, including corresponding envelope solitary and shock wave solutions. 相似文献
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The dynamics of matter waves in linear and nonlinear optical lattices subject to a spatially uniform linear force is studied both analytically and numerically. It is shown that by properly designing the spatial dependence of the scattering length it is possible to induce long-living Bloch oscillations of gap-soliton matter waves in optical lattices. This occurs when the effective nonlinearity and the effective mass of the soliton have opposite signs for all values of the crystal momentum in the Brillouin zone. The results apply to all systems modeled by the periodic nonlinear Schr?dinger equation, including propagation of light in photonic and photorefractive crystals with tilted band structures. 相似文献
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E. S. Sedov A. P. Alodjants S. M. Arakelian Y. Y. Lin R. -K. Lee 《Bulletin of the Russian Academy of Sciences: Physics》2012,76(6):657-662
The coherent and nonlinear properties of a polaritonic crystal (PolC), formed by trapped two-level atoms in an optical cavity array and interacting with an optical field, are analyzed. The nonlinear Schr?dinger equation is considered for the dynamics of coupled atom-light states and low-branch polaritons associated with PolCs in the continuous medium limit. The existence of a stable ground-state PolC wave function is predicted using the variational approach. For negative scattering lengths, the wave function collapses in the presence of small quintic nonlinearity. 相似文献
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We demonstrate that families of vortex solitons are possible in a bidispersive three-dimensional nonlinear Schr?dinger equation. These solutions can be considered as extensions of two-dimensional dark vortex solitons which, along the third dimension, remain localized due to the interplay between dispersion and nonlinearity. Such vortex solitons can be observed in optical media with normal dispersion, normal diffraction, and defocusing nonlinearity. 相似文献
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S. K. Adhikari 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(2):279-286
Using variational and numerical solutions we show that
stationary
negative-energy localized (normalizable) bound states can appear in the
three-dimensional nonlinear Schr?dinger equation with a finite
square-well potential for a range of nonlinearity parameters. Below a
critical attractive nonlinearity, the system becomes unstable and
experiences collapse. Above a limiting repulsive nonlinearity, the
system becomes highly repulsive and cannot be bound. The system also
allows nonnormalizable states of infinite norm at positive energies in
the continuum. The normalizable negative-energy bound states could be
created in BECs and studied in the laboratory with present knowhow. 相似文献
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We construct the fourth-order inhomogeneous generalized HS model and investigate the integrability property of the supersymmetric integrable system. Moreover, in terms of the gauge transformation, we investigate the corresponding gauge equivalent counterparts under two constraints, i.e., the super inhomogeneous generalized nonlinear Schr?dinger equation and the fermionic inhomogeneous generalized nonlinear Schr?dinger equation. 相似文献
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R. A. Caetano F.A.B.F. de Moura M. L. Lyra 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,80(3):321-324
In this work, we investigate the competition of disorder, nonlinearity and non-adiabatic process on the wave packet dynamics
in 1D. We follow the time evolution of the second moment of the wave packet distribution to characterize its spreading behavior.
In order to describe the dynamical behavior of one-electron wave packets, we solve a discrete nonlinear Schr?dinger equation
which effectively takes into account a diagonal disorder and a nonlinear contribution. Going beyond the adiabatic regime,
we consider that the nonlinearity relaxes in time according to a Debye-like law. In the adiabatic regime, it has been recently
demonstrated that the interplay of disorder and nonlinearity leads to a sub-diffusive spread of the wave packet. Here, we
numerically demonstrate that no sub-diffusive spreading of the second moment of the wave packet distribution takes place when
the finite response time of the nonlinearity is taken into account. 相似文献
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E.V. Doktorov 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):227-231
We argue that the integrable modified nonlinear Schr?dinger equation with the nonlinearity dispersion term is the true starting
point to analytically describe subpicosecond pulse dynamics in monomode fibers. Contrary to the known assertions, solitons
of this equation are free of self-steepening and the breather formation is possible.
Received 29 September 2001 / Received in final form 25 January 2002 Published online 2 October 2002
RID="a"
ID="a"doktorov@dragon.bas-net.by 相似文献
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Nonlinear losses accompanying self-focusing substantially impact the dynamic balance of diffraction and nonlinearity, permitting the existence of localized and stationary solutions of the 2D + 1 nonlinear Schr?dinger equation, which are stable against radial collapse. These are featured by linear, conical tails that continually refill the nonlinear, central spot. An experiment shows that the discovered solution behaves as a strong attractor for the self-focusing dynamics in Kerr media. 相似文献
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We analyze in detail the expansion of a 1D Bose gas after removing the axial confinement. We show that during its one-dimensional expansion the density of the Bose gas does not follow a self-similar solution. Our analysis is based on a nonlinear Schr?dinger equation with variable nonlinearity whose validity is discussed for the expansion problem, by comparing with an exact Bose-Fermi mapping for the case of an initial Tonks-Girardeau gas. For this case, the gas is shown to expand self-similarly, with a different scaling law compared to the one-dimensional Thomas-Fermi condensate. 相似文献
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Freak waves in random oceanic sea states. 总被引:7,自引:0,他引:7
Freak waves are very large, rare events in a random ocean wave train. Here we study their generation in a random sea state characterized by the Joint North Sea Wave Project spectrum. We assume, to cubic order in nonlinearity, that the wave dynamics are governed by the nonlinear Schr?dinger (NLS) equation. We show from extensive numerical simulations of the NLS equation how freak waves in a random sea state are more likely to occur for large values of the Phillips parameter alpha and the enhancement coefficient gamma. Comparison with linear simulations is also reported. 相似文献