Domain Decomposition Method for the $N$-body Time-Independent and Time-Dependent Schr\"odinger Equation

This paper is devoted to the derivation of a pleasingly parallel Galerkin method for the time-independent $N$-body Schr"odinger equation, and its time-dependent version modeling molecules subject to an external electric field. In this goal, we develop a Schwarz Waveform Relaxation (SWR) Domain Decomposition Method (DDM) for the $N$-body Schr"odinger equation. In order to optimize the efficiency and accuracy of the overall algorithm, i) we use mollifiers to regularize the singular potentials and to approximate the Schr"odinger Hamiltonian, ii) we select appropriate orbitals, and iii) we carefully derive and approximate the SWR transmission conditions. Some low dimensional numerical experiments are presented to illustrate the methodology.