Propagation of Gevrey regularity over long times for the fully discrete Lie Trotter splitting scheme applied to the linear Schroedinger equation

François Castella (1, 2) , Guillaume Dujardin (1)

1 IPSO - Invariant Preserving SOlvers
2 IRMAR - Institut de Recherche Mathématique de Rennes

In this paper, we study the linear Schroedinger equation over the d-dimensional torus, with small values of the perturbing potential. We consider numerical approximations of the associated solutions obtained by a symplectic splitting method (to discretize the time variable) in combination with the Fast Fourier Transform algorithm (to discretize the space variable). In this fully discrete setting, we prove that the regularity of the initial datum is preserved over long times, i.e. times that are exponentially long with the time discretization parameter. We here refer to Gevrey regularity, and our estimates turn out to be uniform in the space discretization parameter. This paper extends a previous text by Dujardin and Faou, where a similar result has been obtained in the semi-discrete situation, i.e. when the mere time variable is discretized and space is kept a continuous variable.

Mots clés: Splitting; KAM theory; resonance; normal forms; Gevrey regularity; Schrödinger equation

Domaines: Equations aux dérivées partielles [math.AP]

François Castella, Guillaume Dujardin. Propagation of Gevrey regularity over long times for the fully discrete Lie Trotter splitting scheme applied to the linear Schroedinger equation. ESAIM: Mathematical Modelling and Numerical Analysis, 2009, 43 (4), pp.651--676. ⟨10.1051/m2an/2009028⟩. ⟨hal-00777098⟩