Donsker-Varadhan large deviation principle for locally damped and randomly forced NLS equations
Yuxuan Chen, Shengquan Xiang
TL;DR
This work establishes a Donsker–Varadhan large deviation principle for randomly forced PDEs with damping and degenerate noise acting on finite modes. It introduces a general LDP criterion for random dynamical systems, built on irreducibility and a fixed-rate squeezing condition, and overcomes the challenge of a non-vanishing squeezing rate with a novel bootstrap argument for Lipschitz bounds on Feynman–Kac semigroups. The authors verify the criterion in three settings: a nonlinear Schrödinger equation on $ ext{1D torus}$, a nonlinear wave equation, and the two-dimensional Navier–Stokes system with degenerate noise, obtaining uniform LDPs for empirical measures on the support of the unique invariant measure $ mu_*$. The results pave the way for LDP analyses of broader dissipative PDEs with degenerate forcing and offer a pathway to studying observables via the contraction principle. They also discuss the limitations related to initial data outside $ ext{supp}( mu_*)$ and outline future work on hyperbolic equations with white-in-time noise.
Abstract
We study large deviations from the invariant measure for nonlinear Schrödinger equations with colored noises on determining modes. The proof is based on a new abstract criterion, inspired by [V. Jakšić et al., Comm. Pure Appl. Math., 68 (2015), 2108-2143]. To address the difficulty caused by fixed squeezing rate, we introduce a bootstrap argument to derive Lipschitz estimates for Feynman-Kac semigroups. This criterion is also applicable to wave equations and Navier-Stokes system.
