Dossier Sommaire
Publication date: March–April 2018Source: Comptes Rendus Physique, Volume 19, Issue 3Author(s): (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - July 11, 2018 Category: Physics Source Type: research
Foreword
Publication date: March–April 2018Source: Comptes Rendus Physique, Volume 19, Issue 3Author(s): Claude Weisbuch, Erich Spitz, Aurélien David (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - July 11, 2018 Category: Physics Source Type: research
Historical perspective on the physics of artificial lighting
We describe the evolution of lighting technologies used throughout the ages, and how the need for improvements was such that any new technology giving better and cheaper lighting was immediately implemented. Thus, every revolution in energy sources – gas, petrol electricity – was first put to large-scale use in lighting. We describe in some detail several “ancient” techniques of scientific interest, along with their physical limitations. Electroluminescence – the phenomenon by which LEDs directly convert electricity into light – was long thought to only be of use for indicators or flat panel displays supposed t...
Source: Comptes Rendus Physique - July 11, 2018 Category: Physics Source Type: research
Invention, development, and status of the blue light-emitting diode, the enabler of solid-state lighting
Publication date: March–April 2018Source: Comptes Rendus Physique, Volume 19, Issue 3Author(s): Daniel Feezell, Shuji NakamuraAbstractThe realization of the first high-brightness blue-light-emitting diodes (LEDs) in 1993 sparked a more than twenty-year period of intensive research to improve their efficiency. Solutions to critical challenges related to material quality, light extraction, and internal quantum efficiency have now enabled highly efficient blue LEDs that are used to generate white light in solid-state lighting systems that surpass the efficiency of conventional incandescent lighting by 15–20×. Here we dis...
Source: Comptes Rendus Physique - July 11, 2018 Category: Physics Source Type: research
LED lighting efficacy: Status and directions
Publication date: March–April 2018Source: Comptes Rendus Physique, Volume 19, Issue 3Author(s): Paul Morgan Pattison, Monica Hansen, Jeffrey Y. TsaoAbstractA monumental shift from conventional lighting technologies (incandescent, fluorescent, high intensity discharge) to LED lighting is currently transpiring. The primary driver for this shift has been energy efficiency and associated cost savings. LED lighting is now more efficacious than any of the conventional lighting technologies with room to still improve. Near term, phosphor-converted LED packages have the potential for efficacy improvement between 160 lm/W (now) t...
Source: Comptes Rendus Physique - July 11, 2018 Category: Physics Source Type: research
Dislocations hétéro-interfaciales vis perçant une plaquette mince
Publication date: Available online 26 April 2018Source: Comptes Rendus PhysiqueAuthor(s): Salem Neily, Hajer Ghabri, Sami Youssef, Roland BonnetRésuméEn microscopie électronique à transmission et haute résolution, l'échantillon est transparent aux électrons et son épaisseur est souvent inférieure à environ 10 nm. Lorsqu'il contient un défaut linéaire comme une dislocation vis, l'image obtenue peut montrer des perturbations plus ou moins importantes due à la relaxation élastique au voisinage des deux surfaces libres. Par conséquent, l'interprétation théorique d'une image doit inclure cette relaxation dans l...
Source: Comptes Rendus Physique - July 11, 2018 Category: Physics Source Type: research
Many-body localization: An introduction and selected topics
We present a basic introduction to the topic of many-body localization, using the simple example of a quantum spin chain that allows us to illustrate several of the properties of this phase. We then briefly review the current experimental research efforts probing this physics. The largest part of this review is a selection of more specialized questions, some of which are currently under active investigation. We conclude by summarizing the connections between many-body localization and quantum simulations.RésuméQue se passe-t-il dans un système quantique isolé lorsque celui-ci présente du désordre et des interactions ...
Source: Comptes Rendus Physique - July 11, 2018 Category: Physics Source Type: research
Temps de cohérence d'un condensat de Bose–Einstein dans un gaz isolé harmoniquement piégé
Publication date: Available online 7 May 2018Source: Comptes Rendus PhysiqueAuthor(s): Yvan Castin, Alice SinatraRésuméNous étudions la dynamique de phase à l'équilibre d'un condensat dans un gaz de bosons en interaction faible harmoniquement piégé et isolé de l'environnement. Nous trouvons qu'au bout d'un temps long devant le temps de collision typique entre les quasi-particules de Bogolioubov, la variance du déphasage du condensat comporte en général un terme balistique quadratique en temps et un terme diffusif affine en temps. Nous donnons des expressions analytiques des coefficients correspondants, à la lim...
Source: Comptes Rendus Physique - July 11, 2018 Category: Physics Source Type: research
Driven dissipative dynamics and topology of quantum impurity systems
We present different recent applications of this method: (i) how topological properties of the spin such as the Berry curvature and the Chern number can be measured dynamically, and how dissipation affects the topology and the measurement protocol, (ii) how quantum spin chains can experience synchronization dynamics via coupling with a common bath. In the second part of this review, we discuss quantum engineering of spin–boson and related models in circuit quantum electrodynamics (cQED), quantum electrical circuits, and cold-atoms architectures. In different realizations, the Ohmic environment can be represented by a lon...
Source: Comptes Rendus Physique - July 11, 2018 Category: Physics Source Type: research
RFID: A key technology for Humanity
Publication date: January–February 2018Source: Comptes Rendus Physique, Volume 19, Issues 1–2Author(s): Yvan Duroc, Smail TedjiniAbstractThe RFID (Radio Frequency IDentification) technology is a well-known wireless application for traceability, logistics, and access control. It became ubiquitous in industry and our daily life (ticketing, payment, passports, car keys, etc.). RFID is nowadays a standardized technology; its inherent advantages, which are unitary, identification, wireless communication, and low cost of tags, provide it with decisive practical benefits that drive new developments in terms of concepts and ap...
Source: Comptes Rendus Physique - July 5, 2018 Category: Physics Source Type: research
Editorial Board
Publication date: January–February 2018Source: Comptes Rendus Physique, Volume 19, Issues 1–2Author(s): (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - July 5, 2018 Category: Physics Source Type: research
Drone-borne GPR design: Propagation issues
The objective is to see if a solution can be found in the near future.RésuméDans cet article, nous allons aborder les problèmes de propagation d'onde électromagnétique qui permettra de déterminer la faisabilité d'un capteur radar à pénétration de sol, embarqué sur un drone, destiné aux applications humanitaires, notamment dans le cadre des catastrophes. L'étude de la fréquence, de la polarisation, de la diffusion, de l'atténuation et de la dispersion des signaux radar pénétrant sous la surface permettra de déterminer l'applicabilité d'un capteur sur drone. La fonctionnalité du radar est donc évaluée e...
Source: Comptes Rendus Physique - July 5, 2018 Category: Physics Source Type: research
From quantum physics to digital communication: Single sideband continuous phase modulation
Publication date: January–February 2018Source: Comptes Rendus Physique, Volume 19, Issues 1–2Author(s): Haïfa Farès, D. Christian Glattli, Yves Louët, Jacques Palicot, Christophe Moy, Preden RoulleauAbstractIn the present paper, we propose a new frequency-shift keying continuous phase modulation (FSK–CPM) scheme having, by essence, the interesting feature of single-sideband (SSB) spectrum providing a very compact frequency occupation. First, the original principle, inspired from quantum physics (levitons), is presented. Besides, we address the problem of low-complexity coherent detection of this new waveform, base...
Source: Comptes Rendus Physique - July 5, 2018 Category: Physics Source Type: research
Editorial Board
Publication date: January–February 2018Source: Comptes Rendus Physique, Volume 19, Issues 1–2Author(s): (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - July 5, 2018 Category: Physics Source Type: research
