Single-step Propagators for calculation of time evolution in quantum   systems with arbitrary interactions
  We propose and develop a general method of numerical calculation of the wave function time evolution in a quantum system which is described by Hamiltonian of an arbitrary dimensionality and with arbitrary interactions. For this, we obtain a general n-order single-step propagator, which could be used for the numerical solving of the problem with any prescribed accuracy. We demonstrate an applicability of the proposed approach by considering a propagation of an electron in focused electromagnetic field with vortex electric field component. 
Ivan Gonoskov and Mattias Marklund
physics.atom-ph