Bennett-Brassard 1984 quantum key distribution using conjugate homodyne detection

Journal Article · Wed Jan 20 00:00:00 EST 2021 · Physical Review A

DOI:https://doi.org/10.1103/physreva.103.012606· OSTI ID:1763480

Qi, Bing ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Optical homodyne detection has been widely used in continuous-variable (CV) quantum information processing for measuring field quadrature. In this paper we explore the possibility of operating a conjugate homodyne detection system in “photon counting” mode to implement discrete-variable (DV) quantum key distribution (QKD). A conjugate homodyne detection system, which consists of a beam splitter followed by two optical homodyne detectors, can simultaneously measure a pair of conjugate quadratures $X$ and $P$ of the incoming quantum state. In classical electrodynamics, $X^2+P^2$ is proportional to the energy (the photon number) of the input light. In quantum optics, $X$ and $P$ do not commute and thus the above photon-number measurement is intrinsically noisy. This implies that a blind application of standard security proofs of QKD could result in pessimistic performance. We overcome this obstacle by taking advantage of two special features of the proposed detection scheme. First, the fundamental detection noise associated with vacuum fluctuations cannot be manipulated by an external adversary. Second, the ability to reconstruct the photon number distribution at the receiver's end can place additional constraints on possible attacks from the adversary. As an example, we study the security of the BB84 QKD using conjugate homodyne detection and evaluate its performance through numerical simulations. This study may open the door to a family of QKD protocols, complementary to the well-established DV-QKD based on single-photon detection and CV-QKD based on coherent detection.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Cybersecurity, Energy Security, and Emergency Response (CESER); USDOE Office of Electricity (OE)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1763480
• Journal Information: Physical Review A, Journal Name: Physical Review A Journal Issue: 1 Vol. 103; ISSN 2469-9926
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
quantum cryptography