Experimental Realization of a Multiplexed Quantum Memory of 225 Cells and Entanglement Between 25 Memory Cells

To realize long-distance quantum communication and quantum network, it is required to have multiplexed quantum memory with many memory cells. 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. We also generate multipartite entanglement between 25 (or 9) individually addressable quantum interfaces in a multiplexed atomic quantum memory array and confirm genuine 22 (or 9) partite entanglement, respectively. Experimental entanglement of a record-high number of quantum interfaces makes an important enabling step towards realization of quantum networks, long-distance quantum communication, and multipartite quantum information processing.