Iterative treatment of the Coulomb potential in laser–atom interactions

We discuss a Faddeev-like iterative approach which allows one to consistently include the Coulomb potential in strong field phenomena through a Born series. To assess the validity of this approach, we calculate the probability of excitation to given states of atomic hydrogen exposed to radiation pulses of various frequencies, durations and peak intensities and compare our results with those obtained by solving numerically the time-dependent Schrödinger equation. We obtain excellent agreement for a range of frequencies. As the frequency decreases, many high-order terms have to be included in order to get convergence of the Born series. Our results indicate that this Faddeev-like method is particularly suitable to treat the interaction of atoms with attosecond pulses. For the lowest frequency considered ( ω = 0.057 a.u.), we study in more detail the re-collision-based frustrated tunneling process in atomic hydrogen and compare our results with those existing in the literature. Graphic Abstract