2000-times repeated imaging of strontium atoms in clock-magic tweezer arrays

We demonstrate single-atom resolved imaging with a survival probability of $0.99932(8)$ and a fidelity of $0.99991(1)$, enabling us to perform repeated high-fidelity imaging of single atoms in tweezers for thousands of times. We further observe lifetimes under laser cooling of more than seven minutes, an order of magnitude longer than in previous tweezer studies. Experiments are performed with strontium atoms in $813.4~\text{nm}$ tweezer arrays, which is at a magic wavelength for the clock transition. Tuning to this wavelength is enabled by off-magic Sisyphus cooling on the intercombination line, which lets us choose the tweezer wavelength almost arbitrarily. We find that a single not retro-reflected cooling beam in the radial direction is sufficient for mitigating recoil heating during imaging. Moreover, this cooling technique yields temperatures below $5~\mu$K, as measured by release and recapture. Finally, we demonstrate clock-state resolved detection with average survival probability of $0.996(1)$ and average state detection fidelity of $0.981(1)$. Our work paves the way for atom-by-atom assembly of large defect-free arrays of alkaline-earth atoms, in which repeated interrogation of the clock transition is an imminent possibility.Comment: 6 pages, 5 figures, 1 vide

Mass Economy: The Labor Supply and Our Economic Future

Presents findings on the current health of the state's labor force and provides policy options for attracting and retaining workers, particularly older workers and immigrants

Reactors for microbial electrobiotechnology

From the first electromicrobial experiment to a sophisticated microbial electrochemical process - it all takes place in a reactor. Whereas the reactor design and materials used strongly influence the obtained results, there are no common platforms for MES reactors. This is a critical convention gap, as cross-comparison and benchmarking among MES as well as MES vs. conventional biotechnological processes is needed. Only knowledge driven engineering of MES reactors will pave the way to application and commercialization. In this chapter we first assess the requirements on reactors to be used for bioelectrochemical systems as well as potential losses caused by the reactor design. Subsequently, we compile the main types and designs of reactors used for MES so far, starting from simple H-cells to stirred tank reactors. We conclude with a discussion on the weaknesses and strengths of the existing types of reactors for bioelectrochemical systems that are scored on design criteria and draw conclusions for the future engineering of MES reactors. [GRAPHICS]

Applications hybrides et adaptatives basées Apache Cordova

National audienceDévelopper des applications multiplateformes pour les appareils mobiles est une tâche assez complexe car les différents systèmes qui les animent se sont rendus parfaitement incompatibles en termes de portage d'applications. Cordova, supporté par le groupe Apache, est une alternative de développement multiplateforme mobile se basant sur HTML5, CSS3 et JavaScript. Cordova est une forme de conteneur pour interfacer l'application Web avec les fonctionnalités natives de l'appareil mobile. Pour les étudiants R&T cette plateforme met en valeur les connaissances acquises dans les modules de développement Web et la programmation pour appareils mobiles

Alkaline earth atoms in optical tweezers

We demonstrate single-shot imaging and narrow-line cooling of individual alkaline earth atoms in optical tweezers; specifically, strontium-88 atoms trapped in $515.2~\text{nm}$ light. We achieve high-fidelity single-atom-resolved imaging by detecting photons from the broad singlet transition while cooling on the narrow intercombination line, and extend this technique to highly uniform two-dimensional arrays of $121$ tweezers. Cooling during imaging is based on a previously unobserved narrow-line Sisyphus mechanism, which we predict to be applicable in a wide variety of experimental situations. Further, we demonstrate optically resolved sideband cooling of a single atom close to the motional ground state of a tweezer. Precise determination of losses during imaging indicate that the branching ratio from $^1$P$_1$ to $^1$D$_2$ is more than a factor of two larger than commonly quoted, a discrepancy also predicted by our ab initio calculations. We also measure the differential polarizability of the intercombination line in a $515.2~\text{nm}$ tweezer and achieve a magic-trapping configuration by tuning the tweezer polarization from linear to elliptical. We present calculations, in agreement with our results, which predict a magic crossing for linear polarization at $520(2)~\text{nm}$ and a crossing independent of polarization at 500.65(50)nm. Our results pave the way for a wide range of novel experimental avenues based on individually controlled alkaline earth atoms in tweezers -- from fundamental experiments in atomic physics to quantum computing, simulation, and metrology implementations

Entangling, Controlling, and Detecting Individual Strontium Atoms in Optical Tweezer Arrays

We present a novel experimental platform for quantum and precision science: single strontium atoms trapped in arrays of optical tweezers. We demonstrate development of this platform along three important fronts: single-atom trapping, imaging, and cooling; coherent control of the ultra-narrow clock transition; and inter-atom entanglement via Rydberg interactions. In the context of single-atom physics, we demonstrate trapping in tweezer arrays of one- and two-dimensions as well as cooling to the motional ground state. We furthermore show high-fidelity single-atom imaging with extremely low loss, allowing us to image the same atoms thousands of times before losing them and in principle allowing for the assembly of defect-free atom arrays of several hundred sites. Notably, we show these results in tweezers that are at a magic wavelength for strontium's clock transition. This feature allows us to perform high-fidelity state rotations on the clock transition. We also demonstrate operation of a single-site resolved atomic-array optical clock -- a new atomic clock platform that combines several benefits of optical lattice and single-ion clocks. From the metastable clock state, we drive the atoms to highly-excited Rydberg states to introduce interactions between nearby atoms. Using a Rydberg blockade in an assembled array of atom pairs, we demonstrate generation of two-atom entangled Bell states with a fidelity of &gt;98%, or &gt;99% with correction for state preparation and measurement errors. Furthermore, we demonstrate an auto-ionization state-detection scheme for Rydberg atoms which improves on the infidelity of previous Rydberg state-detection schemes by over an order of magnitude. We conclude with several outlooks, including preliminary data on light-cone correlation spreading in a system of 17 interacting atoms. We also discuss prospects for implementing quantum gates, operating a spin-squeezed clock, increasing system size, quantifying many-body state fidelity, and reducing sources of infidelity.</p

Salle informatique "Administration Systèmes & Services Réseaux"

National audienceLa spécialité "Réseaux et Télécommunications" forme des techniciens supérieurs capables de s'insérer dans les secteurs des réseaux informatiques, télécommunications et du web, ou de poursuivent leurs études en licence professionnelle orientée vers la sécurité et l'administration des réseaux informatiques (ASUR). Le programme pédagogique national a nettement mis l'accent sur l'administration des systèmes et des services de l'Internet en l'affectant d'une charge d'environ 700 heures réparties sur 7 modules dans les 3 premiers semestres. D'une part, parce que ce type d'enseignement est très difficile à mener dans des salles informatiques banalisées, d'autre part, parce que la mise en place d'une pédagogie par projet nous semble être un gage d'une formation de qualité, il nous semble donc important la mise en place du matériels adéquats (Serveurs, Stations de travail, Unités mobiles) à vocation purement pédagogique pour l'équipement d'une salle de travaux pratiques afin de mettre en oeuvre une solution répondant aux exigences pédagogiques de nos modules d'enseignements. Ainsi, dans ce papier nous présentons la solution technique mise en place dans notre département R&T pour favoriser la pédagogie par projet et l'évaluation par compétences dans les modules administration systèmes et services réseaux

A Graph-Based Web Services Discovery Framework for IoT EcoSystem

Nowadays, the Internet of Things (IoT) represents an important topic and research domain with multiple objectives. However, most IoTs communicate poorly across the multitude of network interfaces. It should be preferably used a single universal application layer protocol for the devices and services interconnection, regardless of how they are physically connected. The IoT paradigm boosts the device connectivity and the user accessibility benefits of services introduced within the network of connected objects associated with a context-awareness. Within this frame of reference, Web service is the appropriate technological approach to exhibit a set of related IoT functionalities loosely coupled with other services discovered or composed through the Web. In this work, we consider the heterogeneity of connecting technologies for IoT and the applications and devices integration in a single interoperable framework as a research objective. With this in mind, we introduce a five layers multigraph model for Web Services discovery and recommendation, and we address Web services-based applications for IoT data integration. The launched service discovery process permits the interaction between the user/application and the IoT environment. In this context, the choice of suitable services represents a challenge that covers the functionality and the required quality to combine composite services, namely mashups for IoT data management and interconnection. For proof of concept, we test a RESTful Web Services framework as an experimental platform to animate a graph-based approach for dynamic IoT services discovery. We develop a recommender system that performs graph analytics to produce a set of services according to the user's request. The quality of the recommendation process is evaluated by analyzing the correlation of user satisfaction

High-Fidelity Control, Detection, and Entanglement of Alkaline-Earth Rydberg Atoms

Trapped neutral atoms have become a prominent platform for quantum science, where entanglement fidelity records have been set using highly excited Rydberg states. However, controlled two-qubit entanglement generation has so far been limited to alkali species, leaving the exploitation of more complex electronic structures as an open frontier that could lead to improved fidelities and fundamentally different applications such as quantum-enhanced optical clocks. Here, we demonstrate a novel approach utilizing the two-valence electron structure of individual alkaline-earth Rydberg atoms. We find fidelities for Rydberg state detection, single-atom Rabi operations and two-atom entanglement that surpass previously published values. Our results pave the way for novel applications, including programmable quantum metrology and hybrid atom–ion systems, and set the stage for alkaline-earth based quantum computing architectures