Abstract
The twin-field (TF) quantum key distribution (QKD) protocol and its variants are highly attractive because they can beat the well-known fundamental limit of the secret key rate for point-to-point QKD without quantum repeaters (repeaterless bound). In this Letter, we perform a proof-of-principle experimental demonstration of TFQKD based on the protocol proposed by Curty, Azuma, and Lo, which removes the need for postselection on the matching of a global phase from the original TFQKD scheme and can deliver a high secret key rate. Furthermore, we employ a Sagnac loop structure to help overcome the major difficulty in the practical implementation of TFQKD, namely, the need to stabilize the phase of the quantum state over kilometers of fiber. As a proof-of-principle demonstration, the estimated secure key rate from our experimental TFQKD data at the high loss region surpasses the repeaterless bound of QKD with current technology.
- Received 27 February 2019
- Revised 8 May 2019
DOI:https://doi.org/10.1103/PhysRevLett.123.100506
© 2019 American Physical Society
Physics Subject Headings (PhySH)
Synopsis
Long-Haul Quantum Key Distribution
Published 5 September 2019
Two independent studies demonstrate the practicality of twin-field quantum key distribution—a promising approach to performing quantum cryptography over long distances.
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