Einstein-Yang-Mills theory : I. Asymptotic symmetries

Asymptotic symmetries of the Einstein-Yang-Mills system with or without cosmological constant are explicitly worked out in a unified manner. In agreement with a recent conjecture, one finds a Virasoro-Kac-Moody type algebra not only in three dimensions but also in the four dimensional asymptotically flat case.Comment: 12 pages Latex fil

Three-dimensional asymptotically flat Einstein-Maxwell theory

Three-dimensional Einstein-Maxwell theory with non trivial asymptotics at null infinity is solved. The symmetry algebra is a Virasoro-Kac-Moody type algebra that extends the bms3 algebra of the purely gravitational case. Solution space involves logarithms and provides a tractable example of a polyhomogeneous solution space. The associated surface charges are non-integrable and non-conserved due to the presence of electromagnetic news. As in the four dimensional purely gravitational case, their algebra involves a field-dependent central charge.Comment: 19 pages. Typos corrected, one section added for discussing the main result. To appear in Classical and Quantum Gravit

Conformal symmetries of gravity from asymptotic methods: further developments

In this thesis, the symmetry structure of gravitational theories at null infinity is studied further, in the case of pure gravity in four dimensions and also in the case of Einstein-Yang-Mills theory in $d$ dimensions with and without a cosmological constant. The first part of this thesis is devoted to the presentation of asymptotic methods (symmetries, solution space and surface charges) applied to gravity in the case of the BMS gauge in three and four spacetime dimensions. The second part of this thesis contains the original contributions. Firstly, it is shown that the enhancement from Lorentz to Virasoro algebra also occurs for asymptotically flat spacetimes defined in the sense of Newman-Unti. As a first application, the transformation laws of the Newman-Penrose coefficients characterizing solution space of the Newman-Unti approach are worked out, focusing on the inhomogeneous terms that contain the information about central extensions of the theory. These transformations laws make the conformal structure particularly transparent, and constitute the main original result of the thesis. Secondly, asymptotic symmetries of the Einstein-Yang-Mills system with or without cosmological constant are explicitly worked out in a unified manner in $d$ dimensions. In agreement with a recent conjecture, a Virasoro-Kac-Moody type algebra is found not only in three dimensions but also in the four dimensional asymptotically flat case. These two parts of the thesis are supplemented by appendices.Comment: PhD thesis, 144 pages; v2: reference 35 has been update

Une belle gauloise... A propos d'une fibule inscrite de Laon

International audienceA Roman brooch in shoe sole shape, found at Laon (Aisne), shows an inscription associating Latin and Gaulish : ave vimpi. The morphological study of the item, replaced in its typo-chronolgical context of the 2nd c. AD, gives the opportunity to re-examine the dali life accessories using the two languages, with special focus on the occurrences of the Gaulish word "vimpi".Une fibule romaine en forme de semelle de chaussure, trouvée à laon (Aisne), porte une inscription associant latin et gaulois : ave vimpi. L'étude morphologique de cet objet, replacé dans le cadre typo-chronologique du IIe s. de n. ère, fournit l'occasion de revenir sur les objets de la vie quotidienne utilisant ces deux langues, et notamment les attestations du mot gaulois "vimpi"

Les ZIEE - un nouveau moyen d'imposer des projets économiques dans les territoires

International audienceLes lois de décentralisation, suivies des lois Grenelle, avaient eu, semble-t-il, pour objectif d'inciter à un développement économique moins centralisé, adapté aux besoins et aux enjeux des territoires, en termes d'emploi, de capacités et de sensibilité environnementale. On assiste cependant aujourd'hui à une inversion de tendance : la reprise en main de l'Etat se manifeste dans une ambition qui consiste désormais à trouver des territoires d'accueil pour les projets économiques, quel que soit leur coût écologique, plutôt que développer des projets de territoires conçus localement et dans le respect de l'environnement. L'article 16 de la loi n° 2014-1 du 2 janvier 2014 habilitant le Gouvernement à simplifier et sécuriser la vie des entreprises, en autorisant i le Gouvernement à définir par ordonnance des « zones présentant un intérêt majeur pour l'implantation d'activités économiques identifiées [ZIEE], dans lesquelles les enjeux environnementaux font l'objet d'un traitement anticipé » et à en fixer le régime juridique dérogatoire est une manifestation évidente de cette évolution

Ten Years of Valuation of the Local Impact of Atmospheric Pollution: from Scientific Assessments to Political Decisions

This paper focuses on the economic valuation of the impact of local air pollution. Two main issues are considered: 1. The scientific issue: what is estimated, how and why? The main studies from the nineties are presented here. Two strong issues are stressed, with the diversity of valuation methods, on the one hand, and the debates on how to take the long term into account and the discount technique, on the other. 2. The political issue: how the results from the economic field are analysed and used to establish official values for public policies? The methods used in the transport sector in three different European countries (France, Sweden and Switzerland) are studied here.To conclude, we highlight the discrepancy between these two processes and, wherever possible, offer solutions to reach better synergy.Local air pollution ; External costs ; Economic valuation ; Official values ; Public decision ; International comparison

Bulletin of the University of San Diego College for Men 1964-1965

114 pages : illustrations, photographs ; 21.5 cmhttps://digital.sandiego.edu/coursecatalogs-cfm/1011/thumbnail.jp

Scaling properties of work fluctuations after quenches at quantum transitions

We study the scaling properties of the statistics of the work done on a generic many-body system at a quantum phase transition of any order and type, arising from quenches of a driving control parameter. For this purpose we exploit a dynamic finite-size scaling framework. Namely, we put forward the existence of a nontrivial finite-size scaling limit for the work distribution, defined as the large-size limit when appropriate scaling variables are kept fixed. The corresponding scaling behaviors are thoroughly verified by means of analytical and numerical calculations in two paradigmatic many-body systems as the quantum Ising model and the Bose-Hubbard model.Comment: 30 pages, 6 figures. Revised versio