Allard-Type Regularity for Varifolds with Prescribed Contact Angle

Abstract

Given a bounded $C^2$ domain in $\mathbb{R}^{n+1}$ and an integral $n$-rectifiable varifold $V$ with bounded first variation and bounded generalized mean curvature. Given a $C^1$ function $\theta$ defined on the boundary of the domain with range $(0,\pi)$, we assume $V$ has prescribed contact angle $\theta$ with $\partial \Omega$ and the tangent cone of $V$ at a point $X \in \partial \Omega$ is a half-hyperplane of density one. Then we can show that the support of $V$ is a $C^{1,\gamma}$ hypersurface with boundary near $X$ for some $\gamma \in (0,1)$

Publication
Submitted. arXiv:2403.17415, 2024

Main results

This paper establishes a boundary Allard theorem for varifolds with prescribed contact angle, including variable angles and ambient metrics of low regularity.

Boundary regularity

A multiplicity-one tangent half-plane gives smooth structure

If a boundary point admits a multiplicity-one tangent half-hyperplane, then the support is locally a $C^{1,\gamma}$ hypersurface with boundary for some $\gamma\in(0,1)$.

Contact angle

The variational angle is recovered geometrically

On the regular support, the geometric contact angle is the prescribed angle (apart from the explicitly identified orthogonal alternative); the ambiguity disappears under a natural nonorthogonality condition.

Density criterion

Mass control alone suffices in favorable regimes

For two-dimensional varifolds, or in every dimension when the angle is sufficiently close to $90^\circ$, a quantitative boundary density bound implies the required regularity.

Proof strategy

The proof is carried out in a flattened half-space equipped with a $C^1$ metric, so it remains intrinsic to the codimension-one contact-angle problem. It combines a boundary monotonicity formula with an $L^2$ height and tilt estimate, a blow-up analysis, and geometric excess decay. A reflection idea inspired by Leon Simon explains how the boundary term and the capillary angle are incorporated into a stationary comparison object.

Gaoming Wang
Gaoming Wang
Assistant Professor

My research interests include Geometric Analysis and Partial Differential Equations.