Synchronous Quantum Memories with Time-symmetric Pulses

We propose a dynamical approach to quantum memories using a synchronous oscillator-cavity model, in which the coupling is shaped in time to provide the optimum interface to a symmetric input pulse. This overcomes the known difficulties of achieving high quantum input-output fidelity with storage times long compared to the input signal duration. Our generic model is applicable to any linear storage medium ranging from a superconducting device to an atomic medium. We show that with temporal modulation of coupling and/or detuning, it is possible to mode-match to time-symmetric pulses that have identical pulse shapes on input and output.