On smoothing estimates in modulation spaces and the nonlinear Schrödinger equation with slowly decaying initial data

Abstract

We show new local $L^p$-smoothing estimates for the Schrödinger equation with initial data in modulation spaces via decoupling inequalities. Furthermore, we probe necessary conditions by Knapp-type examples for space-time estimates of solutions with initial data in modulation and $L^p$-spaces. The examples show sharpness of the smoothing estimates up to the endpoint regularity in a certain range. Moreover, the examples rule out global Strichartz estimates for initial data in $L^p({\mathbb{R}}^d)$ for $d\ge 1$ and $p>2$, which was previously known for $d\ge 2$. The estimates are applied to show new local and global well-posedness results for the cubic nonlinear Schrödinger equation on the line. Lastly, we show ${\ell }^2$-decoupling inequalities for variable-coefficient versions of elliptic and non-elliptic Schrödinger phase functions.

revised version, 32 pages

References in corpus (2)

• Kakeya sets of curves
• A local smoothing estimate in higher dimensions

Cited by in corpus (5)

• Local smoothing and Hardy spaces for Fourier integral operators
• Nonlinear wave equations with slowly decaying initial data
• Global well-posedness and equicontinuity for mKdV in modulation spaces
• Local smoothing and Hardy spaces for Fourier integral operators on manifolds
• Function spaces for decoupling