Critical points of the two-dimensional Ambrosio-Tortorelli functional with convergence of the phase-field energy

TL;DR

This paper studies the behavior of critical points of the Ambrosio-Tortorelli functional in two dimensions, showing convergence to Mumford-Shah critical points under phase-field energy convergence, without requiring full energy convergence.

Contribution

It extends previous results by proving convergence of critical points to Mumford-Shah critical points using only phase-field energy convergence in two dimensions.

Findings

Critical points converge in $L^2$ to a limit in $SBV^2$

Limit function is a Mumford-Shah critical point

Convergence holds under phase-field energy only

Abstract

We consider a family $\{(u_\varepsilon, v_\varepsilon)\}_{\varepsilon>0}$ of critical points of the Ambrosio-Tortorelli functional. Assuming a uniform energy bound, the sequence $\{(u_\varepsilon, v_\varepsilon)\}_{\varepsilon>0}$ converges in $L^2(\Omega)$ to a limit $(u, 1)$ as $\varepsilon \to 0$, where $u$ is in $SBV^2(\Omega)$. It was previously shown that if the full Ambrosio-Tortorelli energy associated to $(u_\varepsilon,v_\varepsilon)$ converges to the Mumford-Shah energy of $u$, then the first inner variation converges as well. In particular, $u$ is a critical point of the Mumford-Shah functional in the sense of inner variations. In this work, focusing on the two-dimensional setting, we extend this result under the sole convergence of the phase-field energy to the length energy term in the Mumford-Shah functional.