Exchange and Distribution of Multipartite Entanglement via Atomic Coherence

We present a convenient and efficient way to exchange and distribute multipartite entangled state via atomic coherence induced by electromagnetically induced transparency (EIT) in an atomic ensemble. By using the EIT-based nondegenerate four-wave mixing processes, the generation, exchange, and distribution of light-light, atom-light, and atom-atom multipartite entanglement can be achieved in a deterministic way with only coherent light fields. This EIT-induced atomic coherence acts as a quantum information processor and has the function of quantum beam splitter, quantum frequency converter, quantum entangler, and quantum repeater, which greatly facilitates the operations in quantum information processing, and holds promising applications in realistic scalable quantum communication and quantum networks