Work

Long-range photonic device-independent quantum key distribution using spontaneous parametric down-conversion sources and linear optics

Year: 2026

Type: article

Abstract: We address the question of the implementation of long-distance device-independent quantum key distribution (DI QKD) by proposing two experimentally viable schemes. Those schemes use only spontaneous parametric down-conversion sources and linear optics. They achieve favorable key rate scaling proportional to the square root of channel transmittance η t , matching the twin-field protocol advantage. We demonstrate positive asymptotic key rates at detector efficiencies as low as 80%, bringing DI QKD within the reach of current superconducting detector technology. Our security analysis employs the entropy accumulation theorem to establish rigorous finite-size bounds, achieving finite-key rates at a detector efficiency of 90%. This work represents a critical milestone toward device-independent security in quantum communication networks, providing experimentalists with practical implementation pathways while maintaining the strongest possible security guarantees against quantum adversaries.

Source: Physical Review Research

DOI: 10.1103/ycd9-nc6q

Authors: Morteza Moradi, Maryam Afsary, Piotr Mironowicz, Enky Oudot, Magdalena Stobińska-Moretto