Oblique and checkerboard patterns in the quenched Cahn-Hilliard model

TL;DR

This paper investigates the emergence of oblique and checkerboard patterns in a two-dimensional quenched Cahn-Hilliard model, using bifurcation analysis and functional analytic methods to understand pattern selection under heterogeneities.

Contribution

It introduces an abstract framework for analyzing pattern formation in quenched Cahn-Hilliard systems, including bifurcation analysis and numerical investigation of specific examples.

Findings

Patterns arise via an $O(2)$-Hopf bifurcation as quenching speed varies.

The approach addresses neutral spectrum and mass-flux issues using exponential weights and restrictions.

Explicit example demonstrates the applicability of the theoretical results.

Abstract

We consider transversely modulated fronts in a directionally quenched Cahn-Hilliard equation, posed on a two-dimensional infinite channel, with both parameter and source-term type heterogeneities. Such quenching heterogeneities travel through the domain, excite instabilities, and can select the pattern formed in their wake. We in particular study striped patterns which are oblique to the quenching direction and checkerboard type patterns. Under generic spectral assumptions, these patterns arise via an $O(2)$-Hopf bifurcation as the quenching speed is varied, with symmetries arising from translations and reflections in the transverse variable. We employ an abstract functional analytic approach to establish such patterns near the bifurcation point. Exponential weights are used to address neutral continuous spectrum, and a co-domain restriction is used to address neutral mass-flux. We also give a method to determine the direction of bifurcation of fronts. We then give an explicit example for which our hypotheses are satisfied and for which bifurcating fronts can be investigated numerically.