Small-amplitude self-similar solutions for one-dimensional nonlinear dispersive equations
Simão Correia, Gonçalo Pereira, Thyago S. R. Santos
TL;DR
The work addresses the existence of small-amplitude self-similar solutions for 1D scale-invariant dispersive equations, including the cubic NLS, mBO, DNLS, and 4KdV. It develops a robust Fourier-analytic framework that absorbs divergent high-frequency interactions through explicit ansätze (e.g., $S_A$ and $S_{A,a,B}$) and employs fixed-point theory in Fourier-Lebesgue-type spaces, supported by detailed multilinear estimates. The main contributions are the construction of self-similar profiles for all four models with precise frequency-space asymptotics, the establishment of data-to-scattering maps linking low- and high-frequency data, and the demonstration that these maps yield unique small-amplitude self-similar solutions. The results illuminate the role of self-similar structures in dispersive dynamics, providing a path toward finite-energy self-similar solutions and informing long-time behavior and potential blow-up scenarios in 1D systems.
Abstract
Given a nonlinear dispersive equation which admits a scaling invariance, there may exist self-similar solutions. In this work, we present a systematic approach for the construction of small-amplitude self-similar solutions, together with precise asymptotic descriptions at both small and large frequency scales. These ideas are then applied to three classic dispersive models: the modified Benjamin-Ono, the quartic Korteweg-de Vries and the cubic nonlinear Schrödinger equations.
