Multi-qubit time-bin quantum RAM
  We have proposed a scheme of multi-qubit \textit{quantum random access memory} (qRAM) based on the impedance matched photon echo quantum memory incorporated together with the control three-level atom in two coupled QED cavities. A set of matching conditions for basic physical parameters of the qRAM scheme that provides an efficient quantum control of the fast single photon storage and read-out has been found. In particular, it was found that the qRAM operation is determined by the properties of the photonic molecular realized in the qRAM dynamics. Herein, the maximal efficiency of the qRAM is achieved when the cooperativety parameter of the photonic molecular equals to unity that can be easily experimentally implemented. The quantum address of the stored photonic qubits can be put into practice when the address is encoded in photonic multi-time-bin state. We discuss the advantages of the qRAM in terms of working with multi-qubit states and the implementation by current quantum technologies in the optical and microwave domains. 
E. S. Moiseev and S. A. Moiseev
quant-ph