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Variational Approach to the Modulational Instability

Z. Rapti·P. G. Kevrekidis·A. Smerzi·A. R. Bishop
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Abstract

We study the modulational stability of the nonlinear Schrödinger equation (NLS) using a time-dependent variational approach. Within this framework, we derive ordinary differential equations (ODEs) for the time evolution of the amplitude and phase of modulational perturbations. Analyzing the ensuing ODEs, we re-derive the classical modulational instability criterion. The case (relevant to applications in optics and Bose-Einstein condensation) where the coefficients of the equation are time-dependent, is also examined.

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Z. Rapti, P. G. Kevrekidis, A. Smerzi, A. R. Bishop. 2004-04-25. Variational Approach to the Modulational Instability. https://doi.org/10.1103/physreve.69.017601

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