Tunneling and traversal of ultracold atoms through vacuum-induced potentials - art. no. 065802

We examine the pas,;age of ultracold two-level atoms through the potential produced by the vacuum of the cavity field. We find that the phase time may be considered as the appropriate measure of the time required for the atom to traverse the cavity. The phase tunneling time for ultracold atoms exhib its both super- and sub-classical time and we show how this behavior may be understood in terms of the momentum dependence of the phase of transmissio n amplitude. The passage of the atom through the cavity is unique, as it in volves a coherent addition of the transition amplitudes corresponding to bo th barrier and well.