Finite point blowup for the critical generalized Korteweg-de Vries equation

TL;DR

This paper constructs solutions for the critical generalized Korteweg-de Vries equation that blow up at a finite point with a novel rate, addressing an open question about finite point blow-up and expanding understanding of blow-up dynamics.

Contribution

It introduces the first known finite point blow-up solutions with a new blow-up rate for the critical gKdV equation, challenging previous assumptions.

Findings

Constructed finite point blow-up solutions.

Discovered a new blow-up rate between known rates.

Reopened questions on possible blow-up rates.

Abstract

In the last twenty years, there have been significant advances in the study of the blow-up phenomenon for the critical generalized Korteweg-de Vries equation, including the determination of sufficient conditions for blowup, the stability of blowup in a refined topology and the classification of minimal mass blowup. Exotic blow-up solutions with a continuum of blow-up rates and multi-point blow-up solutions were also constructed. However, all these results, as well as numerical simulations, involve the bubbling of a solitary wave going at infinity at the blow-up time, which means that the blow-up dynamics and the residue are eventually uncoupled. Even at the formal level, there was no indication whether blowup at a finite point could occur for this equation. In this article, we answer this question by constructing solutions that blow up in finite time under the form of a single-bubble concentrating the ground state at a finite point with an unforeseen blow-up rate. Finding a blow-up rate intermediate between the self-similar rate and other rates previously known also reopens the question of which blow-up rates are actually possible for this equation.