Gradient flow finite element discretisations with energy-based adaptivity for excited states of Schrödingers equation

Abstract: We present an effective numerical procedure, which is based on the computational scheme from [Heid et al., arXiv:1906.06954], for the numerical approximation of excited states of Schr\"odingers equation. In particular, this procedure employs an adaptive interplay of gradient flow iterations and local mesh refinements, leading to a guaranteed energy decay in each step of the algorithm. The computational tests highlight that this strategy is able to provide highly accurate results, with optimal convergence rate with respect to the number of degrees of freedom.