2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/116701In this paper we are interested in constructing WKB approximations for the non linear cubic Schrödinger equation on a Riemannian surface which has a stable geodesic. These approximate solutions will lead to some instability properties of the equation.20 pagesAnalysis of PDEs35Q55; 35B35; 35R25The WKB method and geometric instability for non linear Schrodinger equations on surfacestext