  Experiments on atoms in intense laser pulses and the corresponding exact ab
initio solutions of the time-dependent Schr\"odinger equation (TDSE) yield
photoelectron spectra with low-energy features that are not reproduced by the
otherwise successful work horse of strong field laser physics: the "strong
field approximation" (SFA). In the semi-classical limit, the SFA possesses an
appealing interpretation in terms of interfering quantum trajectories. It is
shown that a conceptually simple extension towards the inclusion of Coulomb
effects yields very good agreement with exact TDSE results. Moreover, the
Coulomb quantum orbits allow for a physically intuitive interpretation and
detailed analysis of all low-energy features in the semi-classical regime, in
particular the recently discovered "low-energy structure" [C.I. Blaga et al.,
Nature Physics 5, 335 (2009) and W. Quan et al., Phys. Rev. Lett. 103, 093001
(2009)].
