Ergodicity of 2D singular stochastic Navier-Stokes equations
Martin Hairer, Wenhao Zhao
TL;DR
This work proves ergodicity for the 2D stochastic Navier–Stokes equations driven by a rough noise with near-white-noise regularity. By introducing a novel two-frequency ansatz and a refined Da Prato–Debussche-type decomposition, the authors obtain a uniform-in-time Lyapunov bound and build invariant measures with stretched exponential tails. They then establish exponential mixing under a non-degeneracy condition on the noise, using strong Feller properties and a support theorem to obtain irreducibility. The results advance the understanding of singular SPDEs without strong damping, offering a framework potentially applicable to stochastic Yang–Mills-type models and other critical SPDEs.
Abstract
We consider the 2D stochastic Navier-Stokes equations driven by noise that has the regularity of space-time white noise but doesn't exactly coincide with it. We show that, provided that the intensity of the noise is sufficiently weak at high frequencies, this systems admits uniform bounds in time, so that it has an invariant measure, for which we obtain stretched exponential tail bounds.
