Protocols and techniques for a scalable atom-photon quantum network

Quantum networks based on atomic qubits and scattered photons provide a promising way to build a largescale quantum information processor. We review quantum protocols for generating entanglement and operating gates between two distant atomic qubits, which can be used for constructing scalable atom–photon quantum networks. We emphasize the crucial role of collecting light from atomic qubits for large-scale networking and describe two techniques to enhance light collection using reflective optics or optical cavities. A brief survey of some applications for scalable and efficient atom–photon networks is also provided.