  Large scale quantum information processing requires stable and long-lived
quantum memories. Here, using atom-photon entanglement, we propose an
experimentally feasible scheme to realize decoherence-free quantum memory with
atomic ensembles, and show one of its applications, remote transfer of unknown
quantum state, based on laser manipulation of atomic ensembles, photonic state
operation through optical elements, and single-photon detection with moderate
efficiency. The scheme, with inherent fault-tolerance to the practical noise
and imperfections, allows one to retrieve the information in the memory for
further quantum information processing within the reach of current technology.
