High fidelity and flexible quantum state transfer in the atom-coupled cavity hybrid system

We investigate a system composed of N coupled cavities (linear array) and two-level atoms interacting one at a time. Adjusting appropriately the atom-field detuning, and making the hopping rate of photons between neighboring cavities, A, greater than the atom-field coupling g (i.e. A >> N (3/2) g), we can eliminate the interaction of the atom with the non-resonant normal modes reducing the dynamics to the interaction of the atom with only a single-mode. As an application of this interaction, we propose a two-step protocol for quantum communication of an arbitrary atomic quantum state between distant coupled cavities. In the ideal case, the coupled cavities system acts as a perfect quantum bus and we obtain a flexible and perfect quantum communication for any N. Considering the influence of dissipation, an interesting parity effect emerges and we still obtain a high fidelity quantum state transfer for an appreciable number of cavities with current experimental parameters. We also studied important sources of imperfections during the procedure.