Experimental realization of random access quantum memory of 105 qubits

To realize long-distance quantum communication through the quantum repeater network, it is desirable to have a random access quantum memory with many memory cells to have the capability of storing many qubits. And each qubit can be individually addressed in the memory cells, programmable written into and read out from the memory cell to a flying qubit with location independent access time. Here we report an experiment that realizes a random access quantum memory of 210 individually accessible memory cells in a macroscopic atomic ensemble, which can store at least 105 qubits. As a key enabler for a wide range of applications in quantum repeater, we demonstrate that quantum information can be stored into any neighboring memory cells with high fidelity, and more than one flying optical qubits can be stored into pair of memory cells individually one time and then read out after a programmable time in controllable order with high fidelity. The memory is based on electromagnetically-induced transparency in a single spatially-multiplexed ensemble of Rb atoms.