The “father” of microanalysis: Raymond Castaing, creator of a generation of scientific instruments, still in worldwide operation
Publication date: Available online 15 February 2019Source: Comptes Rendus PhysiqueAuthor(s): Christian ColliexAbstractThis manuscript emphasizes the leading role of Raymond Castaing in the conception, realization, and use of three major families of scientific instruments for local analysis of matter. Starting from his early studies with his research director, André Guinier, on the visualization of the GP zones in metal alloys, Raymond Castaing has introduced different stages of innovation for the identification of the elements present in the smallest volume of material. These were successively the X-ray electron probe, th...
Source: Comptes Rendus Physique - February 16, 2019 Category: Physics Source Type: research
The early days of quantum optics in France
Publication date: Available online 15 February 2019Source: Comptes Rendus PhysiqueAuthor(s): Claude Cohen-TannoudjiAbstractWe review a few early studies on atom–photon interactions which took place in France after World War II and before the seventies. Several examples are discussed, including double resonance and optical pumping, radiofrequency multiphoton processes, quantum interference effects in radiative processes, master equation description of atom–photon interactions, optical resonators and laser media, etc. We try to point out the continuity which exists between these early studies and more recent investigatio...
Source: Comptes Rendus Physique - February 16, 2019 Category: Physics Source Type: research
Completion and extension of the periodic table of elements beyond uranium
Publication date: Available online 15 February 2019Source: Comptes Rendus PhysiqueAuthor(s): Robert GuillaumontAbstractIn the 1940s, the search for elements beyond uranium led to the discoveries of the neutron-induced fission of uranium and of eleven trans-uranium radioelements, belonging to the actinide series. The best-known of the actinide elements is plutonium. Plutonium suffers neutron fission, as uranium, and, since 1940, humanity lives in the nuclear age, the age of the release of the fantastic nuclear energy. These discoveries resulted from continuous research efforts on natural radioelements, initiated in 1898 by ...
Source: Comptes Rendus Physique - February 16, 2019 Category: Physics Source Type: research
Les origines du système métrique en France et la Convention du mètre de 1875, qui a ouvert la voie au Système international d'unités et à sa révision de 2018
Publication date: Available online 14 February 2019Source: Comptes Rendus PhysiqueAuthor(s): Suzanne Débarbat, Terry QuinnRésuméL'importante révision du Système international d'unités (SI), qui est intervenue lors de la 26e Conférence générale des poids et mesures (CGPM), en novembre 2018, constitue l'aboutissement de près de 250 années de développement des idées quant à la meilleure façon de définir un système d'unités de mesures qui soit le plus étroitement lié à la nature. Dans la première partie, nous évoquons l'histoire des unités ayant abouti à la création du système métrique décimal en F...
Source: Comptes Rendus Physique - February 15, 2019 Category: Physics Source Type: research
Étalement de la phase et cohérence temporelle d'un gaz de fermions condensé par paires à basse température
Publication date: Available online 8 February 2019Source: Comptes Rendus PhysiqueAuthor(s): Yvan CastinRésuméUn condensat de paires dans un gaz tridimensionnel de fermions de spin 1/2 isolé, homogène, non polarisé, de taille finie et de température extrêmement basse, mais non nulle, subit au cours du temps un changement de phase θˆ(t)−θˆ(0) avec une composante aléatoire, ne serait-ce que par couplage aux phonons thermiques du gaz. À l'aide de la seconde relation de Josephson quantique reliant dθˆ/dt aux opérateurs nombres d'occupation des modes de phonons et d'équations cinétiques linéarisées donnant ...
Source: Comptes Rendus Physique - February 8, 2019 Category: Physics Source Type: research
Pierre-Gilles de Gennes: Beautiful and mysterious liquid crystals
Publication date: Available online 30 January 2019Source: Comptes Rendus PhysiqueAuthor(s): Pawel PieranskiAbstractThe articles of Pierre-Gilles de Gennes on liquid crystals published between 1968 and 1972 in the Comptes rendus de l'Académie des sciences appear today as models of conciseness. On barely three pages, with a few words and equations, de Gennes was able to give answers to enigmas posed by strange and often beautiful phenomena occurring in liquid crystals. Thread-like disclinations in nematics and cholesterics, dislocations in smectics or milky aspect of nematics due to light scattering are a few examples of th...
Source: Comptes Rendus Physique - January 30, 2019 Category: Physics Source Type: research
Silicon spheres for the future realization of the kilogram and the mole
Publication date: Available online 17 January 2019Source: Comptes Rendus PhysiqueAuthor(s): Horst Bettin, Kenichi Fujii, Arnold NicolausAbstractNew definitions of the units for amount of substance – the mole – and for mass – the kilogram – will presumably come into force on the World Metrology Day 2019. In the revised SI, the mole will be defined by a fixed value of the Avogadro constant and the kilogram by a fixed value of the Planck constant. The X-ray-crystal-density (XRCD) method has been used for the determination of these fundamental constants by counting the number of atoms in 28Si-enriched spheres. Thus, si...
Source: Comptes Rendus Physique - January 18, 2019 Category: Physics Source Type: research
A consistent unified framework for the new system of units: Matter–wave optics
Publication date: Available online 11 January 2019Source: Comptes Rendus PhysiqueAuthor(s): Christian J. BordéAbstractThanks to considerable progress in quantum techniques, it has been possible to redefine all SI base units from fundamental constants. A last challenge is to produce a unified framework for fundamental metrology in which all base quantities and relevant fundamental constants appear naturally and consistently. We suggest a generalized 5D framework in which both gravito-inertial and electromagnetic interactions have a natural geometrical signification and in which all measurements can be reduced to phase dete...
Source: Comptes Rendus Physique - January 12, 2019 Category: Physics Source Type: research
Determinations of the Boltzmann constant
Publication date: Available online 20 December 2018Source: Comptes Rendus PhysiqueAuthor(s): Laurent Pitre, Mark D. Plimmer, Fernando Sparasci, Marc E. HimbertAbstractWe review measurements of the Boltzmann constant, k, the value of which is soon to be fixed at exactly 1.380649×10−23 J⋅K−1 for the future revised Système international of units. In addition to a description of the theoretical background and of diverse experimental techniques (acoustic thermometry, Johnson noise thermometry, dielectric constant gas thermometry, and Doppler broadened molecular spectroscopy), the article highlights the decisive role of ...
Source: Comptes Rendus Physique - December 20, 2018 Category: Physics Source Type: research
Editorial Board
Publication date: December 2018Source: Comptes Rendus Physique, Volume 19, Issue 8Author(s): (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - December 6, 2018 Category: Physics Source Type: research
Dossier Sommaire
Publication date: December 2018Source: Comptes Rendus Physique, Volume 19, Issue 8Author(s): (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - December 6, 2018 Category: Physics Source Type: research
Foreword
Publication date: December 2018Source: Comptes Rendus Physique, Volume 19, Issue 8Author(s): Jean-Philippe Couzinié, François Willaime (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - December 6, 2018 Category: Physics Source Type: research
Editorial Board
Publication date: December 2018Source: Comptes Rendus Physique, Volume 19, Issue 8Author(s): (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - December 6, 2018 Category: Physics Source Type: research
Dossier Sommaire
Publication date: November 2018Source: Comptes Rendus Physique, Volume 19, Issue 7Author(s): (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - November 30, 2018 Category: Physics Source Type: research
Editorial Board
Publication date: November 2018Source: Comptes Rendus Physique, Volume 19, Issue 7Author(s): (Source: Comptes Rendus Physique)
Source: Comptes Rendus Physique - November 30, 2018 Category: Physics Source Type: research
