English

Renormalization of a 1d quadratic Schr{\"o}dinger model with additive noise

Analysis of PDEs 2025-12-03 v3 Probability

Abstract

The study is devoted to the interpretation and wellposedness of the stochastic NLS model \begin{equation*} (\imath \partial_t-\Delta)u=|u|^2+\dot{B}, \quad u_0=0,\quad \quad t\in \mathbb{R}, \ x\in \mathbb{T}, \end{equation*} where B˙\dot{B} stands for a space-time fractional noise with index H=(H0,H1)H=(H_0,H_1) in a subset of (0,1)2(0,1)^{2}. We first establish that in the situation where 0<2H0+H120<2H_0+H_1\leq 2, the equation cannot be interpreted in a (classical) functional sense.\\ \indent Our investigations then focus on the rough regime corresponding to the condition 74<2H0+H12\frac74<2H_0+H_1\leq 2. In this specific case, we exhibit an \textit{explicit} renormalization procedure allowing to restore the (local) convergence of the approximated solutions. We follow a pathwise-type approach emphasizing the distinction between the stochastic objects at the core of the dynamics and the general deterministic machinery.

Keywords

Cite

@article{arxiv.2304.03114,
  title  = {Renormalization of a 1d quadratic Schr{\"o}dinger model with additive noise},
  author = {Aurélien Deya and Reika Fukuizumi and Laurent Thomann},
  journal= {arXiv preprint arXiv:2304.03114},
  year   = {2025}
}

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59 pages