High-detection efficiency and low-timing jitter with amorphous superconducting nanowire single-photon detectors

Recent progress in the development of superconducting nanowire single-photon detectors (SNSPDs) made of amorphous material has delivered excellent performances, and has had a great impact on a range of research fields. Despite showing the highest system detection efficiency (SDE) ever reported with SNSPDs, amorphous materials typically lead to lower critical currents, which impacts on their jitter performance. Combining a very low jitter and a high SDE remains a challenge. Here, we report on highly efficient superconducting nanowire single-photon detectors based on amorphous MoSi, combining system jitters as low as 26 ps and a SDE of 80% at 1550 nm. We also report detailed observations on the jitter behaviour, which hints at intrinsic limitations and leads to practical implications for SNSPD performance

High-efficiency and fast photon-number resolving parallel superconducting nanowire single-photon detector

Photon-number resolving (PNR) single-photon detectors are an enabling technology in many areas such as photonic quantum computing, non-classical light source characterisation and quantum imaging. Here, we demonstrate high-efficiency PNR detectors using a parallel superconducting nanowire single-photon detector (P-SNSPD) architecture that does not suffer from crosstalk between the pixels and that is free of latching. The behavior of the detector is modelled and used to predict the possible outcomes given a certain number of incoming photons. We apply our model to a 4-pixel P-SNSPD with a system detection efficiency of 92.5%. We also demonstrate how this detector allows reconstructing the photon-number statistics of a coherent source of light, which paves the way towards the characterisation of the photon statistics of other types of light source using a single detector.Comment: 8 pages, 7 figure

GHz detection rates and dynamic photon-number resolution with superconducting nanowire arrays

Superconducting-nanowire single-photon detectors (SNSPDs) have enabled the realization of several quantum optics technologies thanks to their high detection efficiency, low dark-counts, and fast recovery time. However, the widespread use of technologies such as linear optical quantum computing (LOQC), quasi-deterministic single photon sources and quantum repeaters requires faster detectors that can distinguish between different photon number states. Here, we report the fabrication of an SNSPD array composed of 14 independent pixels, achieving a system detection efficiency (SDE) of 90% in the telecom band. By reading each pixel of the array independently we show that the detector can detect telecom photons at 1.5 GHz with 45% absolute SDE. We exploit the dynamic PNR of the array to demonstrate accurate state reconstruction for different photon-number statistics for a wide range of light inputs, including operation with long-duration light pulses, as commonly obtained with some cavity-based sources. We show 2-photon and 3-photon fidelities of 74% and 57% respectively, which represent state-of-the-art results for fiber-coupled SNSPDs

Heralded distribution of single-photon path entanglement

We report the experimental realization of heralded distribution of single-photon path entanglement at telecommunication wavelengths in a repeater-like architecture. The entanglement is established upon detection of a single photon, originating from one of two spontaneous parametric down conversion photon pair sources, after erasing the photon's which-path information. In order to certify the entanglement, we use an entanglement witness which does not rely on post-selection. We herald entanglement between two locations, separated by a total distance of 2 km of optical fiber, at a rate of 1.6 kHz. This work paves the way towards high-rate and practical quantum repeater architectures.Comment: 5+9 pages, 7 figure

Fast Single Photon Detectors and real-time Key Distillation: Enabling High Secret Key Rate QKD Systems

Quantum Key Distribution has made continuous progress over the last 20 years and is now commercially available. However, the secret key rates (SKR) are still limited to a few Mbps. Here, we present a custom multipixel superconducting nanowire single-photon detectors and fast acquisition and real-time key distillation electronics, removing two roadblocks and allowing an increase of the SKR of more than an order of magnitude. In combination with a simple 2.5 GHz clocked time-bin quantum key distribution system, we can generate secret keys at a rate of 64 Mbps over a distance of 10.0 km and at a rate of 3.0 Mbps over a distance of 102.4 km with real-time key distillation.Comment: 5 pages, 5 figures, submitted to Nature Photonic

Antibodies to TRIM46 are associated with paraneoplastic neurological syndromes.

Paraneoplastic neurological syndromes (PNS) are often characterized by the presence of antineuronal antibodies in patient serum or cerebrospinal fluid. The detection of antineuronal antibodies has proven to be a useful tool in PNS diagnosis and the search for an underlying tumor. Here, we describe three patients with autoantibodies to several epitopes of the axon initial segment protein tripartite motif 46 (TRIM46). We show that anti-TRIM46 antibodies are easy to detect in routine immunohistochemistry screening and can be confirmed by western blotting and cell-based assay. Anti-TRIM46 antibodies can occur in patients with diverse neurological syndromes and are associated with small-cell lung carcinoma

Superconducting nanowire single photon detectors for high-rate quantum communication

The important development of quantum technologies during the past decade brought the need for efficient, fast and precise single-photon detection. Superconducting Nanowire Single-Photon Detectors (SNSPDs) are currently considered as the detection method of choice when extreme performances are required. This thesis aimed at investigating this technology, with the objective of improving existing detectors for high-rate applications in quantum communication. This document presents the work and result achieved over four years dedicated to the subject. During this thesis, single-photon detection based on superconducting nanowire has been investigated, with a particular focus on specific requirements for high speed quantum communication applications. The work achieved ranges from the design and nano-fabrication of the structures, to the characterization and the understanding of the physics, detection models and fundamental limits of the devices

THERMO-ENVIRONOMIC EVALUATION OF AMMONIA PRODUCTION

The thermo-environomic assessment of the industrial production of ammonia has been investigated in this project. Thermodynamic models for the ammonia synthesis were developed on the flowsheeting software Vali based on the techniques used at LENI. Several process configurations were evaluated for the steam-methane reforming and the biomass gasification processes. Optimized values for key performance indicators were obtained based on sensitivity analysis and multi-objective optimization with respect to maximizing the energy yield while minimizing capital investment and carbon dioxide emissions. Life cycle assessment was performed on the optimized process configuration in order to address the possible process GWP reduction. Energy yields of 65.6% and 50.6%, respectively for the SMR and biomass processes have been obtained with process costs of 201.2 and 330.1 USD/MWh. Associated with literature data, the optimized process designs developed in this project allow to assess the potential of a biomass feedstock for ammonia as transportation fuel

Les taux plasmatiques des nouveaux antiépileptiques reflètent-ils leur efficacité dans l'état de mal ?

L'état de mal épileptique est une urgence neurologique. Deux nouveaux antiépileptiques, le lévétiracétam et le lacosamide, sont de plus en plus utilisés pour sa prise en charge. Il n'existe actuellement que peu de données dans la littérature concernant la dose de charge idéale et les taux plasmatiques cibles pour obtenir un effet thérapeutique. Pour chacun des traitements, nous avons corrélé les taux sanguins médicamenteux, récoltés de manière rétrospective, avec les doses de charge administrées et la réponse clinique, récoltées de manière prospective. La réponse clinique est définie de manière dichotomique comme l'arrêt de l'état de mal après la dose de charge du médicament, ceci dans les 24h et sans introduction d'une autre ligne de traitement. Les corrélations ont été standardisées avec les autres caractéristiques de l'état de mal. Pour le lévétiracétam, nous avons intégré toutes les données de laboratoire disponibles dans un modèle pharmacocinétique destiné à étudier l'exposition moyenne au médicament. Nous avons récolté les données de 40 patients pour le lacosamide et 29 patients pour le lévétiracétam. Dans les deux situations, nous n'avons pas constaté de différence statistiquement significative de taux plasmatiques ou de doses de charge entre les répondeurs et les non-répondeurs. Nous avons cependant identifié des doses de charges minimales (9mg/kg pour le lacosamide, 30mg/kg pour le lévétiracétam) associées à des taux plasmatiques considérés comme « thérapeutiques » en pratique courante. Nous mettons également en évidence la faible corrélation entre les doses de charge de lévétiracétam et les taux plasmatiques correspondants. Nous concluons que les taux plasmatiques ne sont pas corrélés à la réponse clinique. Ceci est probablement dû à un faible effet du traitement lui-même par rapport aux autres facteurs pronostiques de l'état de mal. Nous soulignons la nécessité de la réalisation de nouvelles études prospectives de plus grande taille et avec une récolte standardisée des taux plasmatiques pour répondre à la question de la dose de charge idéale

Thermo-environomic evaluation of the ammonia production

Within the global challenge of sustainable energy supply and greenhouse gas emissions mitigation, carbon capture and storage (CCS) and the deployment of renewable resources are considered as promising solutions. In this context, the production of ammonia mainly used in the fertilizer industry that is responsible for a large part of the global CO2 emissions is analyzed in detail in this study. Considering natural gas and biomass as a resource and the option for CO2 capture and storage, different process configurations are systematically compared with regard to energetic, economic and environmental considerations. A consistent thermo-environonomic optimization approach combining flowsheeting, process integration techniques, economic performance evaluation, life cycle assessment and multi-objective optimization is applied for the conceptual process design and the assessment of the competitiveness and the trade-offs. It is highlighted that the quality of the process integration is a key factor for improving the process performance by valorizing the heat excess through electricity cogeneration. Including CO2 mitigation in the ammonia production allows to reduce the emissions, but leads to a slight efficiency decrease due to the additional energy consumption for the compression. For the natural gas fed process yielding an energy efficiency around 65%, the overall life cycle emissions can however be reduced to 0.79kgCO2/kgNH3 with CO2 capture compared to 1.6kgCO2/kgNH3 without capture and to -1.79kgCO2/kgNH3 for the biomass process having an energy efficiency of 50%. The economic competitiveness highly depends on the resource price and the introduction of a carbon tax. This study reveals the potential of the decarbonization of the fertilizer industry