PARAMETRIC SIMULTONS IN ONE-DIMENSIONAL NONLINEAR LATTICES

• 来源期刊: 中国物理(英文版)
• 学科: 物理学
• 关键词: nonlinear lattice waves solitons simultons
• 年，卷（期）: 2001,（6）
• 页码范围: 523-530
• 页数: 8页
• 分类号: O4
• 语种: 英文

摘要

Parametric simultaneous solitary wave (simulton) excitations are shown to be possible in nonlinear lattices. Taking a one-dimensional diatomic lattice with a cubic potential as an example, we consider the nonlinear coupling between the upper cut-off mode of acoustic branch (as a fundamental wave) and the upper cut-off mode of optical branch (as a second harmonic wave). Based on a quasi-discreteness approach the Karamzin-Sukhorukov equations for two slowly varying amplitudes of the fundamental and the second harmonic waves in the lattice are derived when the condition of second harmonic generation is satisfied. The lattice simulton solutions are given explicitly and the results show that these lattice simultons can be nonpropagating when the wave vectors of the fundamental wave and the second harmonic waves are exactly at π/a (where a is the lattice constant) and zero, respectively.