We study the dynamics of a two-level atom trapped in a double well potential while the atom couples either to a single electromagnetic field mode of a cavity, or to the full continuum of electromagnetic modes in three dimensions. Both studies are within the Lamb-Dicke regime concerning transitions to higher vibrational states, but beyond the Lamb-Dicke regime concerning the tunneling split groundstate. We show that in the first case the coupling between internal and external degrees of freedom of the atom induced by the cavity mode can dramatically change the tunneling behavior, and explore how the tunneling can be controlled coherently through the quantum state of the field mode. In the second case, the tunneling in general shows decoherence, but with a rather counter-intuitive dependence on the spontaneous emission rate. We investigate the light emitted from the tunneling atom and establish that under certain conditions interference fringes may be observed in the emitted light, making thus directly visible the coherent superposition of the atom in two different positions.


Seminar, 18^th of June, 14:30h. Conference Room

Hosted by Dr. Geza Toth