Non-local planelike minimizers and $Γ$-convergence of periodic energies to a local anisotropic perimeter
Serena Dipierro, Matteo Novaga, Enrico Valdinoci, Riccardo Villa
TL;DR
The paper addresses homogenization of a non-local, periodic interface energy by proving the existence of planelike minimizers via a cell-problem framework and calibrations, and establishing that rescaled energies $\mathscr{F}_\varepsilon$ Γ-converge to a local anisotropic perimeter $\mathscr{F}_\phi$. The stable norm $\phi$ is well-defined, continuous, and captures macroscopic anisotropy as the large-scale limit of microscopic non-local interactions. Key contributions include minimality and density estimates for level sets, controlled oscillations implying slab-like planelike interfaces, and a full Γ-convergence theory comprising both liminf and limsup inequalities. The results connect microscopic non-local dynamics to an effective anisotropic surface energy, enabling rigorous homogenization and paving the way for understanding large-scale interface behavior in periodic media.
Abstract
We investigate a homogenization problem related to a non-local interface energy with a periodic forcing term. We show the existence of planelike minimizers for such energy. Moreover, we prove that, under suitable assumptions on the non-local kernel and the external field, the sequence of rescaled energies $Γ$-converges to a suitable local anisotropic perimeter, where the anisotropy is defined as the limit of the normalized energy of a planelike minimizer in larger and larger cubes (i.e., what is called in jargon "stable norm"). To obtain this, we also establish several auxiliary results, including: the minimality of the level sets of the minimizers, explicit bounds on the oscillations of the minimizers, density estimates for almost minimizers, and non-local perimeter estimates in the large.
