Correlations between Rabi oscillations and atomic translational dynamics

We analyze some aspects of the internal and translational dynamics of a two-level atom interacting with a resonant standing wave of an ideal cavity. We show that the cavity vacuum field can split the incoming wave packet of the excited two-level atom into two parts, whose scalar product in the Hilbert space determines the behavior of the Rabi oscillations. The state of the whole system is derived and allows us to study the correlations between the internal and the translational atomic dynamics. We find that these correlations become negligible when the two parts are sufficiently away from each other in the space.