A classification of solitons for the surface diffusion flow of entire graphs
Piotr Rybka, Glen Wheeler
TL;DR
The paper classifies solitons for the surface diffusion flow acting on entire graphs, proving that under general conditions every graphical soliton—steady states, forward/backward self-similar profiles, or travelling waves—must be linear, namely $\\phi(y)=Ay$. The authors develop a curvature-based framework with $k[\\phi]$ and $v[\\phi]$, derive a key angle bound, and employ convex functionals along self-similar profiles to enforce rigidity; for travelling waves, they reduce the profile to a linear form $\\phi(y)=\\frac{b}{a}y$. These results clarify that nontrivial graphical solitons do not exist in this setting, highlighting a sharp contrast with non-graphical solitons and emphasizing the need for unbounded initial data theory to capture richer dynamics.
Abstract
In this article we classify solitons (equilibria, self-similar solutions and travelling waves) for the surface diffusion flow of entire graphs of function over the real line.
