# On the Radius of Analyticity of Solutions to the Cubic Szeg\"o Equation

Authors
Type
Preprint
Publication Date
Aug 06, 2013
Submission Date
Mar 25, 2013
Identifiers
arXiv ID: 1303.6148
Source
arXiv
This paper is concerned with the cubic Szeg\H{o} equation $$i\partial_t u=\Pi(|u|^2 u),$$ defined on the $L^2$ Hardy space on the one-dimensional torus $\mathbb T$, where $\Pi: L^2(\mathbb T)\rightarrow L^2_+(\mathbb T)$ is the Szeg\H{o} projector onto the non-negative frequencies. For analytic initial data, it is shown that the solution remains spatial analytic for all time $t\in (-\infty,\infty)$. In addition, we find a lower bound for the radius of analyticity of the solution. Our method involves energy-like estimates of the special Gevrey class of analytic functions based on the $\ell^1$ norm of Fourier transforms (the Wiener algebra).