Excess-noise-free recording and uploading of nonclassical states to continuous-variable quantum memory

A deterministic excess-noise-free recording of unknown quantum states to continuous-variable quantum atomic memory is proposed. To reach this, the memory experiment is extended by the presqueezing of the recorded state of light and deterministic squeezing post-correction of the recorded state. To upload highly nonclassical resources to the memory, such as single-photon state or superposition of coherent states, a probabilistic method is suggested. With the help of presqueezing of the resource state of light and probabilistic squeezing post-correction, this probabilistic upload approaches a lossless transfer of these highly nonclassical states into the quantum memory. Without the squeezing post-correction, the highly nonclassical state can still be probabilistically uploaded in the limit of a weak light-atom coupling.