Photon counting for quantum key distribution with Peltier cooled InGaAs/InP APD's

The performance of three types of InGaAs/InP avalanche photodiodes is investigated for photon counting at 1550 nm in the temperature range of thermoelectric cooling. The best one yields a dark count probability of $2.8\cdot 10^{-5}$ per gate (2.4 ns) at a detection efficiency of 10% and a temperature of -60C. The afterpulse probability and the timing jitter are also studied. The results obtained are compared with those of other papers and applied to the simulation of a quantum key distribution system. An error rate of 10% would be obtained after 54 kilometers.Comment: 8 pages, 10 figures, submitted to Journal of Modern Optic

Fast and User-friendly Quantum Key Distribution

Some guidelines for the comparison of different quantum key distribution experiments are proposed. An improved 'plug & play' interferometric system allowing fast key exchange is then introduced. Self-alignment and compensation of birefringence remain. Original electronics implementing the BB84 protocol and allowing user-friendly operation is presented. Key creation with 0.1 photon per pulse at a rate of 486 Hz with a 5.4% QBER - corresponding to a net rate of 210Hz - over a 23 Km installed cable was performed.Comment: 21 pages, 6 figures, added referenc

Quantum cloning with an optical fiber amplifier

It has been shown theoretically that a light amplifier working on the physical principle of stimulated emission should achieve optimal quantum cloning of the polarization state of light. We demonstrate close-to-optimal universal quantum cloning of polarization in a standard fiber amplifier for telecom wavelengths. For cloning 1 --> 2 we find a fidelity of 0.82, the optimal value being 5/6 = 0.83.Comment: 4 pages, 3 figure

Describing adverse events in Swiss hospitalized oncology patients using the Global Trigger Tool

The occurrence rate of adverse events (AEs) related to care among hospitalized oncology patients in Switzerland remains unknown. The primary objective of this study was to describe, for the first time, the occurrence rate, type, severity of harm, and preventability of AEs related to care, reported in health records of hospitalized hematological and solid-tumor cancer patients in three Swiss hospitals.; Using an adapted version of the validated Global Trigger Tool (GTT) from the Institute for Healthcare Improvement, we conducted a retrospective record review of patients discharged from oncology units over a 6-week period during 2018. Our convenience sample included all records from adult patients (≥18 years of age), diagnosed with cancer, and hospitalized (>24 hours). Per the GTT method, two trained nurses independently assessed patient records to identify AEs using triggers, and physicians from the included units analyzed the consensus of the two nurses. Together, they assessed the severity and preventability of each AE.; From the sample of 224 reviewed records, we identified 661 triggers and 169 AEs in 94 of them (42%). Pain related to care was the most frequent AE (n = 29), followed by constipation (n = 17). AEs rates were 75.4 per 100 admissions and 106.6 per 1000 patient days. Most of the identified AEs (78%) caused temporary harm to the patient and required an intervention. Among AEs during hospitalization (n = 125), 76 (61%) were considered not preventable, 28 (22%) preventable, and 21 (17%) undetermined.; About half of the hospitalized oncology patients suffered from at least one AE related to care during their hospitalization. Pain, constipation, and nosocomial infections were the most frequent AEs. It is, therefore, essential to identify AEs to guide future clinical practice initiatives to ensure patient safety

Quantum Cryptography

Quantum cryptography could well be the first application of quantum mechanics at the individual quanta level. The very fast progress in both theory and experiments over the recent years are reviewed, with emphasis on open questions and technological issues.Comment: 55 pages, 32 figures; to appear in Reviews of Modern Physic

International Conference on Quantum Technologies for High-Energy Physics (QT4HEP22)

Keynote talk and discussion on current challenges and opportunitie

Automated 'plug & play' quantum key distribution

An improved 'plug & play' interferometric system for quantum key distribution is presented. Self-alignment and compensation of birefringence remain, while limitations due to reflections are overcome. Original electronics implementing the BB84 protocol makes adjustment simple. Key creation with 0.1 photon per pulse at a rate of 325Hz with a 2.9% QBER, corresponding to a net rate of 210Hz, over a 23km installed cable was realised