Blowup rate for rotational NLS with a repulsive potential
Yi Hu, Yongki Lee, Shijun Zheng
TL;DR
Addressing the mass-critical nonlinear Schrödinger equation with rotation and a repulsive harmonic potential, the paper proves a log-log blowup rate for initial data near the ground state, via a virial identity and the $\mathcal{R}_\gamma$-transform that connects RNLS to the classical NLS. It establishes an $L^2$-threshold framework, analyzes limiting behavior and mass concentration near blowup, and shows that larger $|\gamma|$ can yield global solutions, contrasting with the attractive case. The results are complemented by numerics in 2D that illustrate blowup profiles and rates, supporting the theoretical predictions. Overall, the work extends the log-log blowup theory to rotating, repulsive-oscillator settings and provides a detailed mechanism for mass concentration and lifespan modulation by the repulsive potential.
Abstract
In this paper we give an analytical proof of the ``$\log$-$\log$'' blowup rate for mass-critical nonlinear Schrödinger equation (NLS) with a rotation ($Ω\neq 0$) and a repulsive harmonic potential $V_γ(x) = \textrm{sgn}(γ) γ^2 |x|^2$, $γ< 0$ when the initial data has a mass slightly above that of $Q$, the ground state solution to the free NLS. The proof is based on a virial identity and an $\mathcal{R}_γ$-transform, a pseudo-conformal transform in this setting. Further, we obtain a limiting behavior description concerning the mass concentration near blowup time. A remarkable finding is that increasing the value $|γ|$ for the repulsive potential $V_γ$ can give rise to global in time solution for the focusing RNLS, which is in contrast to the case where $γ$ is positive. This kind of phenomenon was earlier observed in the non-rotational case $Ω= 0$ in Carles' work. In addition, we provide numerical simulations to partially illustrate the blowup profile along with the blowup rate using dynamic rescaling and adaptive mesh refinement method.
