  To realize long-distance quantum communication and quantum network, it is
required to have multiplexed quantum memory with many memory cells. Each memory
cell needs to be individually addressable and independently accessible. Here we
report an experiment that realizes a multiplexed DLCZ-type quantum memory with
225 individually accessible memory cells in a macroscopic atomic ensemble. As a
key element for quantum repeaters, we demonstrate that entanglement with flying
optical qubits can be stored into any neighboring memory cells and read out
after a programmable time with high fidelity. Experimental realization of a
multiplexed quantum memory with many individually accessible memory cells and
programmable control of its addressing and readout makes an important step for
its application in quantum information technology.
