2017/07/31 by Pierre Vernaz-Gris, P. Vernaz-Gris, Kun Huang +7 · 168 citations
Computer Science · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Megabit #Multiplexing #Optical storage #Photonics #Quantum Information and Cryptography #Quantum computer #Quantum error correction #Quantum information #Quantum network #Quantum optics and atomic interactions #Qubit #quant-ph
paper · pdf · doi:10.1038/s41467-017-02775-8
published in Nature Communications 9(1), 363 (Nature Portfolio)
openalex created_date 2017/08/08 · openalex publication_date 2018/01/19 · arxiv created 2018/01/31 · arxiv updated 2018/02/02 · openalex updated_date 2026/08/05
Quantum memory for flying optical qubits is a key enabler for a wide range of applications in quantum information. A critical figure of merit is the overall storage and retrieval efficiency. So far, despite the recent achievements of efficient memories for light pulses, the storage of qubits has suffered from limited efficiency. Here we report on a quantum memory for polarization qubits that combines an average conditional fidelity above 99% and efficiency around 68%, thereby demonstrating a reversible qubit mapping where more information is retrieved than lost. The qubits are encoded with weak coherent states at the single-photon level and the memory is based on electromagnetically-induced transparency in an elongated laser-cooled ensemble of cesium atoms, spatially multiplexed for dual-rail storage. This implementation preserves high optical depth on both rails, without compromise between multiplexing and storage efficiency. Our work provides an efficient node for future tests of quantum network functionalities and advanced photonic circuits.