170 research outputs found
Secure Key from Quantum Discord
The study of quantum information processing seeks to characterize the
resources that enable quantum information processing to perform tasks that are
unfeasible or inefficient for classical information processing. Quantum
cryptography is one such task, and researchers have identified entanglement as
a sufficient resource for secure key generation. However, quantum discord,
another type of quantum correlation beyond entanglement, has been found to be
necessary for guaranteeing secure communication due to its direct relation to
information leakage. Despite this, it is a long-standing problem how to make
use of discord to analyze security in a specific quantum cryptography protocol.
Here, based on our proposed quantum discord witness recently, we successfully
address this issue by considering a BB84-like quantum key distribution protocol
and its equivalent entanglement-based version. Our method is robust against
imperfections in qubit sources and qubit measurements as well as basis
misalignment due to quantum channels, which results in a better key rate than
standard BB84 protocol. Those advantages are experimentally demonstrated via
photonic phase encoding systems, which shows the practicality of our results
Unbalanced-basis-misalignment tolerant measurement-device-independent quantum key distribution
Measurement-device-independent quantum key distribution (MDIQKD) is a
revolutionary protocol since it is physically immune to all attacks on the
detection side. However, the protocol still keeps the strict assumptions on the
source side that the four BB84-states must be perfectly prepared to ensure
security. Some protocols release part of the assumptions in the encoding system
to keep the practical security, but the performance would be dramatically
reduced. In this work, we present a MDIQKD protocol that requires less
knowledge of encoding system to combat the troublesome modulation errors and
fluctuations. We have also experimentally demonstrated the protocol. The result
indicates the high-performance and good security for its practical
applications. Besides, its robustness and flexibility exhibit a good value for
complex scenarios such as the QKD networks.Comment: 22 pages, 9 figure
A phase 4 multicentre, 2×2 factorial randomised, double-blind, placebo-controlled trial to investigate the efficacy and safety of tobramycin inhalation solution for Pseudomonas aeruginosa eradication in bronchiectasis:Erase
Chronic Pseudomonas aeruginosa (PA) infection significantly contributes to morbidity and mortality in bronchiectasis patients. Initiating antibiotics early may lead to the eradication of PA. Here we outline the design of a trial (ERASE; NCT06093191) assessing the efficacy and safety of inhaled tobramycin, alone or with oral ciprofloxacin, in bronchiectasis patients with a new isolation of PA. This multicentre, 2×2 factorial randomised, double-blind, placebo-controlled, parallel-group trial includes a 2-week screening period, a 12-week treatment phase (with a combination of ciprofloxacin or a placebo at initial 2 weeks) and a 24-week follow-up. 364 adults with bronchiectasis and a new PA isolation will be randomly assigned to one of four groups: placebo (inhaled saline and ciprofloxacin placebo twice daily), ciprofloxacin alone (750 mg ciprofloxacin and inhaled saline twice daily), inhaled tobramycin alone (inhaled 300 mg tobramycin and ciprofloxacin placebo twice daily) or a combination of both drugs (inhaled 300 mg tobramycin and 750 mg ciprofloxacin twice daily). The primary objective of this study is to assess the proportion of patients successfully eradicating PA in each group by the end of the study. Efficacy will be evaluated based on the eradication rate of PA at other time points (12, 24 and 36 weeks), the occurrence of exacerbations and hospitalisations, time to first pulmonary exacerbations, patient-reported outcomes, symptom measures, pulmonary function tests and the cost of hospitalisations. To date no randomised trial has evaluated the benefit of different PA eradication strategies in bronchiectasis patients. The ERASE trial will therefore generate crucial data to inform future clinical guidelines.</p
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