Source-linked AI summary
Continuous variable quantum key distribution in non-Markovian channels
Ruggero Vasile, Stefano Olivares, Matteo G A Paris, Sabrina Maniscalco
TL;DR
Losses can hide an eavesdropper, while realistic channels may have nonuniform, non-Markovian damping. The paper proposes a coherent-state protocol that compares signals sent through two channel lengths; suitably engineered losses support security at arbitrarily low overall transmission.
Problem
Losses can let eavesdroppers hide, while realistic channels may have nonuniform, environment-dependent losses beyond the uniform damping of Markovian models.
Source: p. 1Method
Alice adds a delay to create two channel-length choices and compares Bob’s measurement distributions to detect an eavesdropper.
Source: pp. 1–2Results
A suitably engineered decay rate supports security at arbitrarily low overall transmission, while non-Markovian loss-rate variation can reveal and sometimes locate Eve.
Source: pp. 1, 3Takeaways & Limitations
Because the detection scheme relies on channel properties rather than distribution-specific features, the authors foresee applying it to squeezed- or entangled-state CV QKD.
Source: p. 4Finite quadrature precision can leave attacks at tE > tE* undetected; security then requires ηNM ≥ ηth.
Source: p. 4
Abstract
from arXiv · showhide
We address continuous variable quantum key distribution (QKD) in non-Markovian lossy channels and show how the non-Markovian features may be exploited to enhance security and/or to detect the presence and the position of an eavesdropper along the transmission line. In particular, we suggest a coherent states QKD protocol which is secure against individual attacks for arbitrarily low values of the overall transmission line. Our scheme relies on specific non-Markovian properties, and cannot be implemented in ordinary Markovian channels characterized by uniform losses.