Tight scaling of key rate for differential-phase-shift quantum key distribution
Year: 2024
Type: article
Abstract: The performance of quantum key distribution protocols is evaluated based on the ease of implementation and key generation rate. Among major protocols, the differential-phase-shift (DPS) protocol has the advantage of simple implementation using a train of coherent pulses and a passive detection unit. Unfortunately, however, its key rate is known to be at least proportional to η 2 with respect to channel transmission η → 0 . If one can only prove the rate proportional to η 2 and cannot improve the analysis beyond that, then the DPS protocol will be deemed inferior to other major protocols, such as the decoy BB84 protocol. In this paper, we consider a type of DPS protocol in which the phase of each emitted block comprising n pulses is randomized and significantly improves the analysis of its key rate. Specifically, we reveal that the key rate is proportional to η 1 + 1 n − 2 and this scaling is tight. This implies that the DPS protocol can achieve a key rate proportional to η for a large number of n , which is the same scaling as the decoy BB84 protocol. Our result suggests that the DPS protocol can achieve a combination of both advantages of ease of implementation and a high key generation rate. Published by the American Physical Society 2024
Source: Physical Review Research
Authors: Akihiro Mizutani, Toyohiro Tsurumaru
Institutions: University of Toyama, Mitsubishi Electric (Japan)
Language: English
Subfield: Artificial Intelligence
Field: Computer Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,625
OpenAlex ID: W4405620864