Hyperbolic $P(Φ)_2$-model on the plane
Tadahiro Oh, Leonardo Tolomeo, Yuzhao Wang, Guangqu Zheng
TL;DR
The paper advances the stochastic quantization of the two-dimensional hyperbolic $ ext{Φ}^{k+1}_2$-model on the plane by constructing a plane Gibbs measure as a large-torus limit and establishing global well-posedness and invariance for SdNLW with Gibbs-distributed data. It develops a rigorous framework of enhanced Gibbs measures to control the interplay between wave and heat analyses, leverages coming-down-from-infinity for the stochastic heat equation, and transfers invariant Gibbs dynamics from large tori to $bR^2$. A key technical achievement is the convergence of enhanced data sets and the associated Gibbs measures in weighted function spaces, ensuring invariance and global dynamics on the plane. The results also yield invariance of the parabolic $ ext{Φ}^{k+1}_2$-measure under the corresponding parabolic dynamics, linking parabolic and hyperbolic stochastic quantization in an unbounded setting.
Abstract
We study the hyperbolic $Φ^{k+1}_2$-model on the plane. By establishing coming down from infinity for the associated stochastic nonlinear heat equation (SNLH) on the plane, we first construct a $Φ^{k+1}_2$-measure on the plane as a limit of the $Φ^{k+1}_2$-measures on large tori. We then study the canonical stochastic quantization of the $Φ^{k+1}_2$-measure on the plane thus constructed, namely, we study the defocusing stochastic damped nonlinear wave equation forced by an additive space-time white noise (= the hyperbolic $Φ^{k+1}_2$-model) on the plane. In particular, by taking a limit of the invariant Gibbs dynamics on large tori constructed by the first two authors with Gubinelli and Koch (2021), we construct invariant Gibbs dynamics for the hyperbolic $Φ^{k+1}_2$-model on the plane. Our main strategy is to develop further the ideas from a recent work on the hyperbolic $Φ^3_3$-model on the three-dimensional torus by the first two authors and Okamoto (2021), and to study convergence of the so-called enhanced Gibbs measures, for which coming down from infinity for the associated SNLH with positive regularity plays a crucial role. By combining wave and heat analysis together with ideas from optimal transport theory, we then conclude global well-posedness of the hyperbolic $Φ^{k+1}_2$-model on the plane and invariance of the associated Gibbs measure. As a byproduct of our argument, we also obtain invariance of the limiting $Φ^{k+1}_2$-measure on the plane under the dynamics of the parabolic $Φ^{k+1}_2$-model.
