We show that an unknown quantum state can be teleported from one free-space atomic ensemble to another by using only coherent light. Neither non-classical light nor cavities are needed in the scheme, which greatly simplifies its experimental implementation.
Protocols for quantum communication between massive particles, such as atoms, are usually based on making use of nonclassical light, and/or superhigh finesse optical cavities are normally needed to enhance interaction between atoms and photons. We demonstrate a remarkable result: by using only coherent light, entanglement can be generated between distant free space atomic ensembles, and an unknown quantum state can thus be teleported from one to another. Neither nonclassical light nor cavities are needed in the scheme, which greatly simplifies its experimental implementation.