Interacting phase fields yielding phase separation on surfaces

TL;DR

This paper develops a diffuse interface model for two-phase biomembranes using coupled phase fields, proving key mathematical properties and applying the model to approximate complex membrane energies.

Contribution

It introduces a novel diffuse interface approach with coupled phase fields for modeling two-phase biomembranes, including mathematical analysis and energy approximation.

Findings

Proved compactness and lower bound results for phase field pairs.

Established a diffuse approximation of a two-phase Willmore functional.

Applied the model to simulate membrane line tension energy.

Abstract

In the present article we study diffuse interface models for two-phase biomembranes. We will do so by starting off with a diffuse interface model on $\mathbb{R}^n$ defined by two coupled phase fields $u,v$. The first phase field $u$ is the diffuse approximation of the interior of the membrane; the second phase field $v$ is the diffuse approximation of the two phases of the membrane. We prove a compactness result and a lower bound in the sense of $\Gamma$-convergence for pairs of phase functions $(u_\varepsilon,v_\varepsilon)$. As an application of this first result, we consider a diffuse approximation of a two-phase Willmore functional plus line tension energy.