  An improved quantum trajectory Monte Carlo method involving the Stark shift
of the initial state, Coulomb potential, and multielectron polarization-induced
dipole potential is used to revisit the origin of the low-energy interference
structure in the photoelectron momentum distribution of the xenon atom
subjected to an intense laser field, and resolve the different contributions of
these three effects. In addition to the well-studied radial finger-like
interference structure, a ring-like interference structure induced by
interference among electron wave packets emitted from multi-cycle time windows
of the laser field is found in the low energy part of the photoelectron
momentum spectrum. It is attributed to the combined effect of the Coulomb
potential and Stark shift. Our finding provides new insight into the imaging of
electron dynamics of atoms and molecules with intense laser fields.
