Defesa de Tese.

Banca examinadora: Prof. Alexei A. Mailybaev (IMPA), orientador Prof. André Nachbin (IMPA) Prof. Felipe Linares (IMPA) Prof. Pavel Lushnikov (University of New Mexico, USA) Prof. Simon Thalabard (Université Cote d'Azur, França) Dr. Dmitry Agafontsev (Shirshov Institute of Oceanology, Russia), suplente

Abstract: In this work we present a systematic numerical study of the post-blowup dynamics of singular solutions of the 1D focusing critical NLS equation in the framework of a nonlinear damped perturbation. The first part of this study shows that initially the post-blowup is well described by the adibatic approximation, in which the collapsing core approaches an universal profile and the solution width is governed by a system of ODEs (reduced system). After that, a non-adiabatic regime is observed soon after the maximum of the solution, in which our direct numerical simulations show a clear deviation from the dynamics based on the reduced system. Our study suggests that such non-adiabatic regime is caused by the increasing influx of mass into the collapsing core of the solution, which is not considered in the derivation of the reduced system. Also, adiabatic theoretical predictions related to the wave-maximum and wave-dissipation are compared with our numerical simulations. The second part of this work corresponds to the non-adiabatic dynamics. Here, numerical simulations reveal a dominant linear regime, caused by the rapid defocusing process. A fact observed in this linear regime is the numerical verification that the collapsing core approaches the universal profile, after removing some oscillations resulting from the interference with the tail. Finally, our numerical study indicates that in the limit of vanishing dissipation, and in a free-space domain, the critical mass is radiated to infinity instantly at the collapse time .