The Willmore Flow of Tori of Revolution

We study long-time existence and asymptotic behavior for the $L^2$-gradient flow of the Willmore energy, under the condition that the initial datum is a torus of revolution. We show that if an initial datum has Willmore energy below $8\pi$ then the solution of the Willmore flow converges for $t \rightarrow \infty$ to the Clifford Torus, possibly rescaled and translated. The energy threshold of $8\pi$ turns out to be optimal for such a convergence result. We give an application to the conformally constrained Willmore minimization problem.