Spatio-temporal second-order quantum correlations of surface plasmon polaritons

We present an experimental methodology to observe spatio-temporal second-order quantum coherence of surface plasmon polaritons which are emitted by nitrogen vacancy color centers attached at the apex of an optical tip. The approach relies on leakage radiation microscopy in the Fourier space and we use this approach to test wave-particle duality for surface plasmon polaritons

Analytic Regularity for Linear Elliptic Systems in Polygons and Polyhedra

We prove weighted anisotropic analytic estimates for solutions of second order elliptic boundary value problems in polyhedra. The weighted analytic classes which we use are the same as those introduced by Guo in 1993 in view of establishing exponential convergence for hp finite element methods in polyhedra. We first give a simple proof of the known weighted analytic regularity in a polygon, relying on a new formulation of elliptic a priori estimates in smooth domains with analytic control of derivatives. The technique is based on dyadic partitions near the corners. This technique can successfully be extended to polyhedra, providing isotropic analytic regularity. This is not optimal, because it does not take advantage of the full regularity along the edges. We combine it with a nested open set technique to obtain the desired three-dimensional anisotropic analytic regularity result. Our proofs are global and do not require the analysis of singular functions.Comment: 54 page

La nouvelle figure du travailleur précaire assisté

Avec l’instauration du Revenu de solidarité active (RSA) en juin 2009, la France connaît une réforme d’envergure de sa politique de lutte contre la pauvreté. D’abord expérimenté dans 34 départements, ce nouveau dispositif semble s’inscrire dans le prolongement des aménagements déjà instaurés dans le passé et visant à permettre le cumul d’un salaire et d’une partie d’un revenu minimum, ce que l’on a qualifié de mécanismes d’intéressement. Mais cette première analyse se révèle insuffisante pour rendre compte de cette réforme et de ses conséquences. Ce dispositif suscite d’importantes controverses entre ceux qui défendent la priorité à l’action contre le développement du phénomène des travailleurs pauvres, et ceux qui dénoncent un risque de fragilisation de la protection du droit du travail, mais aussi d’une partie des actifs occupés par le développement d’un sous-emploi. Dans cet article, nous interprétons cette évolution des politiques sociales en France, en référence à la définition de la pauvreté proposée par Simmel, en insistant sur le sens que pourrait avoir le brouillage des frontières entre travail et assistance.The arrival of the Active Solidarity Benefit (Revenu de solidarité active – RSA) in June 2009 marks a major reform of French anti-poverty policies. First piloted in 34 Departments, the recent programme is a continuation of previously implemented reforms. It permits recipients to receive social assistance while earning a salary. The programme has provoked major controversy between those who prioritise the struggle against the expansion of the category of the working poor and both those who denounce the programme as threatening to weaken labour rights and those who fear it menaces a portion of the employed with under-employment. In this article we provide a reading of this evolution in France’s social policies using Simmel’s definition of poverty, with particular attention going to the possible meaning of the blurring of boundaries between employment and social assistance

Modelling supported driving as an optimal control cycle: Framework and model characteristics

Driver assistance systems support drivers in operating vehicles in a safe, comfortable and efficient way, and thus may induce changes in traffic flow characteristics. This paper puts forward a receding horizon control framework to model driver assistance and cooperative systems. The accelerations of automated vehicles are controlled to optimise a cost function, assuming other vehicles driving at stationary conditions over a prediction horizon. The flexibility of the framework is demonstrated with controller design of Adaptive Cruise Control (ACC) and Cooperative ACC (C-ACC) systems. The proposed ACC and C-ACC model characteristics are investigated analytically, with focus on equilibrium solutions and stability properties. The proposed ACC model produces plausible human car-following behaviour and is unconditionally locally stable. By careful tuning of parameters, the ACC model generates similar stability characteristics as human driver models. The proposed C-ACC model results in convective downstream and absolute string instability, but not convective upstream string instability observed in human-driven traffic and in the ACC model. The control framework and analytical results provide insights into the influences of ACC and C-ACC systems on traffic flow operations.Comment: Submitted to Transportation Research Part C: Emerging Technologie

On the use of chaotic dynamics for mobile network design and analysis: towards a trace data generator

With the constant increase of the number of autonomous vehicles and connected objects, tools to understand and reproduce their mobility models are required. We focus on chaotic dynamics and review their applications in the design of mobility models. We also provide a review of the nonlinear tools used to characterize mobility models, as it can be found in the literature. Finally, we propose a method to generate traces for a given scenario involving moving people, using tools from the nonlinear analysis domain usually dedicated to topological analysis of chaotic attractors.Comment: 22 pages, 7 figures, to be published in Journal of Difference Equations and Application