Noise excess free record/upload of non-classical states to continuous-variable quantum memory

In a recent continuous-variable quantum memory experiment, one quadrature of light pulse is directly uploaded by the light-atom coupling whereas complementary quadrature is obtained by homodyne measurement of the out-coupled light. Subsequently, information from homodyne mea- surement is written into the memory by feed-back electro-optical control of the atomic state. Using the same experimental set-up, a deterministic noise excess free record of unknown quantum states to continuous-variable quantum atomic memory is proposed. Further, the memory experiment is extended by the pre-squeezing of the recorded state of light and squeezing post-correction of the recorded state. To upload a resource to the memory, as single-photon state or superposition of co- herent states, the post-selection of the measurement results from homodyne detection is suggested. Then such the probabilistic upload approaches even a lossless transfer of these highly nonclassical states into the quantum memory.