Some $L^\infty$ solutions of the hyperbolic nonlinear Schrödinger equation and their stability

 11 December 2018
 Mathematics - Research News

Simão Correia, Mário Figueira. Source: Advances in Differential Equations, Volume 24, Number 1/2, 1--30.Abstract:
Consider the hyperbolic nonlinear Schrödinger equation $\mathrm {(HNLS)}$ over $\mathbb R^d$ $$ iu_t + u_{xx} - \Delta_{\textbf{y}} u + \lambda |u|^\sigma u=0. $$ We deduce the conservation laws associated with $\mathrm {(HNLS)}$ and observe the lack of information given by the conserved quantities. We build several classes of particular solutions, including hyperbolically symmetric solutions , spatial plane waves and spatial plane waves , which never lie in $H^1$. Motivated by this, we build suitable functional spaces that include both $H^1$ solutions and these particular classes, and prove local well-posedness on these spaces. Moreover, we prove a stability result for both spatial plane waves and spatial standing waves with respect to small $H^1$ perturbations.