Spatial Atomic Layer Deposition (SALD), an emerging tool for energy materials. Application to new-generation photovoltaic devices and transparent conductive materials
Publication date: Available online 4 October 2017 Source:Comptes Rendus Physique Author(s): David Muñoz-Rojas, Viet Huong Nguyen, César Masse de la Huerta, Sara Aghazadehchors, Carmen Jiménez, Daniel Bellet Materials properties are the keystone of functional devices for energy including energy conversion, harvesting or storage. But to market new energy materials, the development of suitable processing methods allowing affordable prices is needed. Recently, a new approach to atomic layer deposition (ALD) has gained much momentum. This alternative approach is based on separating the precursors in space rather than...
Source: Comptes Rendus Physique - October 5, 2017 Category: Physics Source Type: research
The new paradigm of photovoltaics: From powering satellites to powering humanity
Publication date: Available online 2 October 2017 Source:Comptes Rendus Physique Author(s): Daniel Lincot The photovoltaic effect has been discovered by Edmond Becquerel in 1839. Then it took 115 years to make the first efficient solar cell, with a few watts produced, about 50 years to deploy 3 GW of production capacity worldwide, and only 13 years to reach 300 GW in 2016. 500 GW are expected in 2020, and the TW within the next decade. How did this occur? How photovoltaics work? What is the physical limit of conversion efficiency? What road map for photovoltaics in the energy transition? This paper aims at providing a r...
Source: Comptes Rendus Physique - October 3, 2017 Category: Physics Source Type: research
LEDs for lighting: Basic physics and prospects for energy savings
This article aims at giving an insight on LEDs physics, on the key inventions that led to the 2014 Nobel Prize and on the prospects for energy savings that LEDs could allow. (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - September 30, 2017 Category: Physics Source Type: research
Testing the formation of Majorana states using Majorana polarization
Publication date: Available online 28 September 2017 Source:Comptes Rendus Physique Author(s): Cristina Bena We study the formation of Majorana states in superconductors using Majorana polarization, which can locally evaluate the Majorana character of a given state. We introduce the definition of the Majorana polarization vector and of the corresponding criterion to identify a Majorana state, and we apply it to some simple cases such as a one-dimensional wire with spin-orbit coupling, subject to a Zeeman magnetic field, and proximitized by a superconductor, as well as to an NS junction made with such a wire. We also app...
Source: Comptes Rendus Physique - September 29, 2017 Category: Physics Source Type: research
Lighter structures for transports: The role of innovation in metallurgy
Publication date: Available online 28 September 2017 Source:Comptes Rendus Physique Author(s): Alexis Deschamps, Guilhem Martin, Rémy Dendievel, Hugo P. Van Landeghem The landscape of energy production and use is facing great challenges in the transportation sectors. The two main means of transportation, automobiles and airplanes, are mainly made from metals. The necessity of reducing their carbon emission translates into major stakes for weight reduction, which can only be the result of an interplay between improving the alloys and the part's geometry. This contribution discusses some of the strategies for structur...
Source: Comptes Rendus Physique - September 29, 2017 Category: Physics Source Type: research
ITER: A unique international collaboration to harness the power of the stars
Publication date: Available online 19 September 2017 Source:Comptes Rendus Physique Author(s): Bernard Bigot Harnessing the energy of thermonuclear fusion reactions is one of the greatest challenges of our time. Fusion, the nuclear reaction that powers the Sun and stars would provide mankind with a safe, environmentally benign, and virtually limitless source of energy. (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - September 20, 2017 Category: Physics Source Type: research
The multipurpose water uses of hydropower reservoir: The SHARE concept
Publication date: Available online 18 August 2017 Source:Comptes Rendus Physique Author(s): Emmanuel Branche The production and use of energy and the capture and use of water are vital to the economy and the health and welfare of all nations, and the wise stewardship of these resources is essential to the protection of the environment. After the 6th World Water Forum held in Marseille (France, 2012), Électricité de France (EDF) and the World Water Council (WWC) have agreed to work on “the multipurpose water uses of hydropower reservoirs”. This framework bridges between 6th Forum in Marseille and the 7th Forum in D...
Source: Comptes Rendus Physique - August 18, 2017 Category: Physics Source Type: research
Spectral action gravity and cosmological models
Publication date: Available online 29 May 2017 Source:Comptes Rendus Physique Author(s): Matilde Marcolli This paper surveys recent work of the author and collaborators on cosmological models based on the spectral action functional of gravity. A more detailed presentation of the topics surveyed here will be available in a forthcoming book [1]. (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - May 31, 2017 Category: Physics Source Type: research
Chalcogenide glasses and glass-ceramics: Transparent materials in the infrared for dual applications
Publication date: Available online 30 May 2017 Source:Comptes Rendus Physique Author(s): Laurent Calvez In this paper are described the different research activities that led to the awarding of the Lamb prize by the French Academy of Sciences in order to promote research work on the national defense of France. This research concerns the development of infrared materials for night vision and the development of thermal imagers useful for defense, but also for civilian applications. The contribution has been particularly innovative in different sectors: broadening of chalcogenide glasses window of transparency, IR glass-ce...
Source: Comptes Rendus Physique - May 31, 2017 Category: Physics Source Type: research
CDT and cosmology
Publication date: Available online 26 May 2017 Source:Comptes Rendus Physique Author(s): Lisa Glaser, Renate Loll In the approach of Causal Dynamical Triangulations (CDT), quantum gravity is obtained as a scaling limit of a non-perturbative path integral over space-times whose causal structure plays a crucial role in the construction. After some general considerations about the relation between quantum gravity and cosmology, we examine which aspects of CDT are potentially interesting from a cosmological point of view, focusing on the emergence of a de Sitter universe in CDT quantum gravity. (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - May 26, 2017 Category: Physics Source Type: research
Asymptotically safe cosmology – A status report
Publication date: Available online 26 May 2017 Source:Comptes Rendus Physique Author(s): Alfio Bonanno, Frank Saueressig Asymptotic safety, based on a non-Gaussian fixed point of the gravitational renormalization group flow, provides an elegant mechanism for completing the gravitational force at sub-Planckian scales. At high energies, the fixed point controls the scaling of couplings such that unphysical divergences are absent, while the emergence of classical low-energy physics is linked to a crossover between two renormalization group fixed points. These features make asymptotic safety an attractive framework for the...
Source: Comptes Rendus Physique - May 26, 2017 Category: Physics Source Type: research
Testing different approaches to quantum gravity with cosmology: An overview
Publication date: Available online 22 May 2017 Source:Comptes Rendus Physique Author(s): Aurélien Barrau Among the available quantum gravity proposals, string theory, loop quantum gravity, non-commutative geometry, group field theory, causal sets, asymptotic safety, causal dynamical triangulation, emergent gravity are the best motivated models. As an introductory summary to this dossier of Comptes Rendus Physique, I explain how those different theories can be tested or constrained by cosmological observations. (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - May 22, 2017 Category: Physics Source Type: research
Superconducting millimetre-wave cameras
Publication date: Available online 19 May 2017 Source:Comptes Rendus Physique Author(s): Alessandro Monfardini I present a review of the developments in kinetic inductance detectors (KID) for mm-wave and THz imaging-polarimetry in the framework of the Grenoble collaboration. The main application that we have targeted so far is large field-of-view astronomy. I focus in particular on our own experiment: NIKA2 (Néel IRAM KID Arrays). NIKA2 is today the largest millimetre camera available to the astronomical community for general purpose observations. It consists of a dual-band, dual-polarisation, multi-thousands pixels sy...
Source: Comptes Rendus Physique - May 20, 2017 Category: Physics Source Type: research
String cosmology and the landscape
Publication date: Available online 29 April 2017 Source:Comptes Rendus Physique Author(s): Iosif Bena, Mariana Graña String Theory is believed to have a landscape of 10500 vacua with properties that resemble those of our Universe. The existence of these vacua can be combined with anthropic reasoning to explain some of the hardest problems in cosmology and high-energy physics: the cosmological constant problem, the hierarchy problem, and the un-natural almost-flatness of the inflationary potential. We will explain the construction of these vacua, focusing on the challenges of obtaining vacua with a positive cosmologica...
Source: Comptes Rendus Physique - April 29, 2017 Category: Physics Source Type: research
Evolution of universes in causal set cosmology
Publication date: Available online 27 March 2017 Source:Comptes Rendus Physique Author(s): Fay Dowker, Stav Zalel The causal set approach to the problem of quantum gravity is based on the hypothesis that spacetime is fundamentally discrete. Spacetime discreteness opens the door to novel types of dynamical law for cosmology and the Classical Sequential Growth (CSG) models of Rideout and Sorkin form an interesting class of such laws. It has been shown that a renormalisation of the dynamical parameters of a CSG model occurs whenever the universe undergoes a Big Crunch–Big Bang bounce. In this paper we propose a way to m...
Source: Comptes Rendus Physique - March 28, 2017 Category: Physics Source Type: research
