Abstract

We study the corrector equation in stochastic homogenization for a simplified Bernoulli percolation model on $\mathbb{Z}^d$, $d > 2$. The model is obtained from the classical $\{0,1\}$-Bernoulli bond percolation by conditioning all bonds parallel to the first coordinate direction to be open. As a main result we prove (in fact for a slightly more general model) that stationary correctors exist and that all finite moments of the corrector are bounded. This extends a previous result of Gloria & Otto, where uniformly elliptic conductances are treated, to the degenerate case. With regard to the associated random conductance model, we obtain as a side result that the corrector not only grows subinearly, but slower than any polynomial rate. Our argument combines a quantification of ergodicity by means of a Spectral Gap on Glauber dynamics with regularity estimates on the gradient of the elliptic Green's function.

Highlights

  • We consider the lattice graph (Zd, Bd), d > 2, where Bd denotes the set of nearest-neighbor edges

  • Given a stationary and ergodic probability measure · on Ω – the space of conductance fields a : Bd → [0, 1] – we study the corrector equation from stochastic homogenization, i.e. the elliptic difference equation

  • The goal of the present paper is to extend this result to the case of conductances with degenerate ellipticity

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Summary

Introduction

We consider the lattice graph (Zd, Bd), d > 2, where Bd denotes the set of nearest-neighbor edges. While the asymptotic result of stochastic homogenization holds for general stationary and ergodic coefficients (at least in the uniformly elliptic case), the derivation of error estimates requires a quantification of ergodicity. Since the elliptic estimates that we require are less sensitive to the geometry of the graph, and can be obtained by simpler arguments, we opt for a self-contained proof that only relies on elliptic regularity theory Another interesting, and – as we believe – advantageous property of our approach is that (thanks to the Spectral Gap Estimate) probabilistic and deterministic considerations are well separated, e.g. Proposition 1 is pointwise in a and does not involve the ensemble.

General framework
Lattice and discrete differential calculus
Random conductance field
Main result
Outline and Proof of Theorem 1
Proof of Lemma 3
Proof of Lemma 4 and Lemma 5
Proof of Proposition 1 – Green’s function estimates
Conclusion
Proof of Lemma 6
Full Text
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