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Main Author: Knezevitch, Alexis
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2506.12582
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author Knezevitch, Alexis
author_facet Knezevitch, Alexis
contents We consider the Schrödinger equation on the one dimensional torus with a general odd-power nonlinearity $p \geq 5$, which is known to be globally well-posed in the Sobolev space $H^σ(\mathbb{T})$, for every $σ\geq 1$, thanks to the conservation and finiteness of the energy. For regularities $σ< 1$, where this energy is infinite, we explore a globalization argument adapted to random initial data distributed according to the Gaussian measures $μ_s$, with covariance operator $(1-Δ)^s$, for $s$ in a range $(s_p,\frac{3}{2}]$. We combine a deterministic local Cauchy theory with the quasi-invariance of Gaussian measures $μ_s$, with additional $L^q$-bounds on the Radon-Nikodym derivatives, to prove that the Gaussian initial data generate almost surely global solutions. These $L^q$-bounds are obtained with respect to Gaussian measures accompanied by a cutoff on a renormalization of the energy; the main tools to prove them are the Boué-Dupuis variational formula and a Poincaré-Dulac normal form reduction. This approach is similar in spirit to Bourgain's invariant argument and to a recent work by Forlano-Tolomeo.
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publishDate 2025
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spellingShingle Quantitative quasi-invariance of Gaussian measures below the energy level for the 1D generalized nonlinear Schrödinger equation and application to global well-posedness
Knezevitch, Alexis
Analysis of PDEs
We consider the Schrödinger equation on the one dimensional torus with a general odd-power nonlinearity $p \geq 5$, which is known to be globally well-posed in the Sobolev space $H^σ(\mathbb{T})$, for every $σ\geq 1$, thanks to the conservation and finiteness of the energy. For regularities $σ< 1$, where this energy is infinite, we explore a globalization argument adapted to random initial data distributed according to the Gaussian measures $μ_s$, with covariance operator $(1-Δ)^s$, for $s$ in a range $(s_p,\frac{3}{2}]$. We combine a deterministic local Cauchy theory with the quasi-invariance of Gaussian measures $μ_s$, with additional $L^q$-bounds on the Radon-Nikodym derivatives, to prove that the Gaussian initial data generate almost surely global solutions. These $L^q$-bounds are obtained with respect to Gaussian measures accompanied by a cutoff on a renormalization of the energy; the main tools to prove them are the Boué-Dupuis variational formula and a Poincaré-Dulac normal form reduction. This approach is similar in spirit to Bourgain's invariant argument and to a recent work by Forlano-Tolomeo.
title Quantitative quasi-invariance of Gaussian measures below the energy level for the 1D generalized nonlinear Schrödinger equation and application to global well-posedness
topic Analysis of PDEs
url https://arxiv.org/abs/2506.12582