Both cavity quantum electrodynamics and photons are promising candidates for quantum information processing. We consider a combination of both candidates with a single photon going through spatially separate cavities to entangle the atomic qubits, based on the input-output process of the cavities. We present a general expression for the input-output process regarding the low-
Q cavity confining a single atom, which works in a wide range of parameters. Focusing on low-
Q cavity case, we propose some schemes for quantum information processing with Faraday rotation using single photons, which is much different from the high-
Q cavity and strong-coupling cases.
A interaction model of multi-photon process in the“multi-coupled-atom-cavity”system is constructed.In terms of the cavity quantum electrodynamics,the properties of quantum information transfer in the process of coupled atoms interacting with cavity fields are studied,and the effect of the coupling between atoms on the quantum information transfer is analyzed.It is found that quantum information can be transferred back and forth or be preserved between the cavity fields and atoms in certain time period.The dipole interaction between atoms leads to the quantum entanglement information partially transferred and partially preserved.
We propose a method to implement cavity QED and quantum-information processing in high-
Q cavities with a single trapped but nonlocalized atom. The system is beyond the Lamb-Dicke limit due to the atomic thermal motion. Our method is based on adiabatic passages, which make the relevant dynamics insensitive to the randomness of the atom position with an appropriate interaction configuration. The validity of this method is demonstrated from both approximate analytical calculations and exact numerical simulations. We also discuss various applications of this method based on the current experimental technology.