Central to NQIT’s goal is the ability to interconnect multiple small-scale quantum processors, which requires a reliable interface between atoms and photons. The challenge here is to engineer interactions between atoms and photons, as the quantum information is usually lost before it can be transferred from the moving qubit (the photon) to the stationary qubit (the atom). This prevents us from building an efficient network of quantum processors without using further tricks. We use devices called optical cavities (or simply cavities) to enhance the interaction between atoms and photons.