Threshold for the existence of scattering states for nonlinear Schrödinger equations without gauge invariance
Hayato Miyazaki, Motohiro Sobajima
TL;DR
This work identifies a sharp threshold for scattering in nonlinear Schrödinger equations lacking gauge invariance, showing that in a weighted space $\mathcal{F}H^{\alpha}$ with $\alpha\ge s_c$, no nontrivial scattering states exist when the nonlinearity power satisfies $1<p<p_{\rm st}(d)$. The authors develop a test-function, weak-solution framework and a lower-bound argument tied to the Strauss exponent, demonstrating that even data with compact support can be non-scattering. The results highlight the Strauss exponent as a boundary between scattering and non-scattering behavior in the non-gauge-invariant setting, contrasting with the gauge-invariant case where scattering can persist under certain regimes. The methodology and weighted-space perspective offer a natural approach to the long-time behavior of solutions for subcritical nonlinearities and emphasize the role of structural assumptions on the nonlinearity.
Abstract
This paper is concerned with a threshold phenomenon for the existence of scattering states for nonlinear Schrödinger equations. The nonlinearity includes a non-oscillatory term of the order lower than the Strauss exponent. We show that no scattering states exist for the equation in a weighted Sobolev space. It is emphasized that our method admits initial data with good properties, such as compactly supported smooth functions. The result indicates that the Strauss exponent acts as a threshold for the power of the nonlinearity that determines whether solutions scatter or not in the weighted space.
