Almost sure global nonlinear smoothing for the 2D NLS

Abstract

In this article, we prove an almost-sure global in time nonlinear smoothing effect for NLS on the two-dimensional torus. For deterministic data, this phenomenon was proved for the NLS on the circle by Erdoğan--Tzirakis, which remains unknown on multidimensional torus. Our argument is based on a quantitative quasi-invariance of Gaussian measures with covariance operator $(1-\hat{I}”{)}^{-s}$ for $s>2$.

37pages, comments are welcome