2009/03/18 by Jeffrey H. Shapiro, Shapiro, Jeffrey H.
Computer Science · Physics and Astronomy · #FOS: Physical sciences #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum Physics (quant-ph) #quant-ph
paper · pdf · doi:10.48550/arxiv.0903.3150
4 pages, 2 figures; new version corrects several typographical errors and adds brief comments indicating that the analysis only treats passive eavesdropping
openalex publication_date 2009/03/18 · arxiv created 2009/04/28 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A new paradigm for secure communication, based on quantum illumination, is proposed. Alice uses spontaneous parametric down-conversion to send Bob a set of signal modes over a pure-loss channel while retaining the set of idler modes with which they are maximally entangled. Bob imposes a single information bit on the modes he receives from Alice via binary phase-shift keying. He then adds classical Gaussian noise and sends the noisy modulated modes back to Alice over the same pure-loss channel. Even though the loss and noise destroy any entanglement between the modes that Alice receives from Bob and the idler modes she has retained, she can decode Bob's bit with an error probability that can be orders of magnitude lower than what is achieved by a passive eavesdropper who receives all the photons that are lost en route from Alice to Bob and from Bob to Alice.