University of Toronto PDE/Applied Math/Analysis Seminar Monday 12 February, 12:10-1:00pm 6183 Bahen Center SPEAKER: Jeremy Marzuola (UC Berkeley) TITLE: Stable perturbations of a minimal mass soliton for a saturated NLSE in 3d. ABSTRACT: A nonlinear Schr\"odinger equation with a saturated, focusing nonlinearity will have both orbitally stable and unstable soliton solutions. In particular, we explore stable perturbations of "minimal mass" solitons that live precisely at the boundary of those solutions. Previous works have shown that such solutions are in fact nonlinearly unstable. In the spirit of the works of Schlag and Krieger-Schlag, we construct a stable class (manifold) of perturbations for the minimal mass soliton based on spectral projections and regularity assumptions. Along the way, we discuss various numerical/ analytical techniques for verifying the existence and properties of said solitons, as well as the spectral assumptions required. ------------------------------------------------------------------ University of Toronto PDE/Applied Math/Analysis Seminar http://www.math.toronto.edu/appmath/ 2006-2007 organizers: Pieter Blue pblue@ math.toronto.edu Almut Burchard almut@ math.toronto.edu Robert McCann mccann@ math.toronto.edu ------------------------------------------------------------------