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arXiv · 2504.00094

Quantum cryptography integrating an optical quantum memory

H. Mamann·T. Nieddu·F. Hoffet·M. Bozzio·F. Garreau de Loubresse·I. Kerenidis·E. Diamanti·A. Urvoy·J. Laurat
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Abstract

Developments in scalable quantum networks rely critically on optical quantum memories, which are key components enabling the storage of quantum information. These memories play a pivotal role for entanglement distribution and long-distance quantum communication, with remarkable advances achieved in this context. However, optical memories have broader applications, and their storage and buffering capabilities can benefit a wide range of future quantum technologies. Here we present the first demonstration of a cryptography protocol incorporating an intermediate quantum memory layer. Specifically, we implement Wiesner's unforgeable quantum money primitive with a storage step, rather than as an on-the-fly procedure. This protocol imposes stringent requirements on storage efficiency and noise level to reach a secure regime. We demonstrate the implementation with polarization encoding of weak coherent states of light and a high-efficiency cold-atom-based quantum memory, and validate the full scheme. Our results showcase a major capability, opening new avenues for quantum memory utilization and network functionalities.

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H. Mamann, T. Nieddu, F. Hoffet, M. Bozzio, F. Garreau de Loubresse, I. Kerenidis, E. Diamanti, A. Urvoy, J. Laurat. 2025-03-31. Quantum cryptography integrating an optical quantum memory. https://doi.org/10.1126/sciadv.adx32

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