Two-Scale Macro-Micro decomposition of the Vlasov equation with a strong magnetic field

In this paper, we build a Two-Scale Macro-Micro decomposition of the Vlasov equation with a strong magnetic field. This consists in writing the solution of this equation as a sum of two oscillating functions with circonscribed oscillations. The first of these functions has a shape which is close to the shape of the Two-Scale limit of the solution and the second one is a correction built to offset this imposed shape. The aim of such a decomposition is to be the starting point for the construction of Two-Scale Asymptotic-Preserving Schemes.Comment: Mathematical Models and Methods in Applied Sciences 00, 00 (2012) 1 --

Heisenberg-limited qubit readout with two-mode squeezed light

We show how to use two-mode squeezed light to exponentially enhance cavity-based dispersive qubit measurement. Our scheme enables true Heisenberg-limited scaling of the measurement, and crucially, is not restricted to small dispersive couplings or unrealistically long measurement times. It involves coupling a qubit dispersively to two cavities, and making use of a symmetry in the dynamics of joint cavity quadratures (a so-called quantum-mechanics-free subsystem). We discuss the basic scaling of the scheme and its robustness against imperfections, as well as a realistic implementation in circuit quantum electrodynamics.Comment: 5 pages, 4 figures, Supplemental Materia

Low Voltage Totally Free Flexible RF MEMS Switch With Anti-Stiction System

This paper concerns a new design of RF MEMS switch combined with an innovative process which enable low actuation voltage (<5V) and avoid stiction. First, the structure described with principal design issues, the corresponding anti-stiction system is presented and FEM simulations are done. Then, a short description of the process flow based on two non polymer sacrificial layers. Finally, RF measurements are presented and preliminary experimental protocol and results of anti-stiction validation is detailed. Resulting RF performances are -30dB of isolation and -0.45dB of insertion loss at 10 GHz.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/16838

Emerging visualization techniques to support public participation in urban mass transit planning context

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1999.Includes bibliographical references (leaves 101-104).With the post-modern turn in planning theory, the public's input is now required in a wider variety of areas. Nevertheless, the discourse about planning has remained too technically oriented, depriving the general public from a real understanding of the issues at stake. The development of multi-media, web-based tools could provide the public with common concepts and a common vocabulary to discuss and elaborate a shared vision on planning-related issues. This thesis develops such a tool to educate the public about urban transportation auditory impacts. By combining movies, sounds and simulations, we offer multiple representations of sound in an interactive and interpretative way which could augment the social knowledge about those issues. Furthermore, the same framework could easily be expanded to encompass other technical elements. This tool prefigures one of the multiple ways by which information technologies will impact the planning practice. This thesis will also suggest some of the possible evolutions in the planner's role within this new technology-enhanced environment.by Nicolas A. Ferrand.M.C.P

Infestation hépatique massive et exceptionnelle d’un agneau par des ascaris

Nicolas J. A., Pestre-Alexandre Madeleine. Infestation hépatique massive et exceptionnelle d'un agneau par des ascaris . In: Bulletin de l'Académie Vétérinaire de France tome 127 n°2, 1974. pp. 73-74

The imitation game: Proca stars that can mimic the Schwarzschild shadow

Can a dynamically robust bosonic star (BS) produce an (effective) shadow that mimics that of a black hole (BH)? The BH shadow is linked to the existence of light rings (LRs). For free bosonic fields, yielding mini-BSs, it is known that these stars can become ultra-compact - i.e., possess LRs - but only for perturbatively unstable solutions. We show this remains the case even when different self-interactions are considered. However, an effective shadow can arise in a different way: if BSs reproduce the existence of an innermost stable circular orbit (ISCO) for timelike geodesics (located at $r_{\rm ISCO}=6M$ for a Schwarzschild BH of mass M), the accretion flow morphology around BHs is mimicked and an effective shadow arises in an astrophysical environment. Even though spherical BSs may accommodate stable timelike circular orbits all the way down to their centre, we show the angular velocity along such orbits may have a maximum away from the origin, at $R_{\Omega}$; this scale was recently observed to mimic the BH's ISCO in some scenarios of accretion flow. Then: (i) for free scalar fields or with quartic self-interactions, $R_{\Omega}\neq 0$ only for perturbatively unstable BSs; (ii) for higher scalar self-interactions, e.g. axionic, $R_{\Omega}\neq 0$ is possible for perturbatively stable BSs, but no solution with $R_{\Omega}=6M$ was found in the parameter space explored; (iii) but for free vector fields, yielding Proca stars (PSs), perturbatively stable solutions with $R_{\Omega}\neq 0$ exist, and indeed $R_{\Omega}=6M$ for a particular solution. Thus, dynamically robust spherical PSs can mimic the shadow of a (near-)equilibrium Schwarzschild BH with the same M, in an astrophysical environment, despite the absence of a LR, at least under some observation conditions, as we confirm by comparing the lensing of such PSs and Schwarzschild BHs.Comment: Abstract abridged due to arXiv length limit; 22 pages, 9 figure

Charged black holes with axionic-type couplings: classes of solutions and dynamical scalarization

We consider an augmented Einstein-Maxwell-scalar model including an axionic-type coupling between the scalar and electromagnetic field. We study dyonic black hole solutions in this model. For the canonical axionic coupling emerging from high energy physics, all charged black holes have axion hair. We present their domain of existence and investigate some physical properties. For other axionic-type couplings, two classes of black hole solutions may coexist in the model: scalar-free Reissner-Nordström black holes and scalarized black holes. We show that in some region of the parameter space the scalar-free solutions are unstable. Then, there is nonuniqueness since new scalarized black hole solutions with the same global charges, which are entropically preferred over the scalar-free solutions and, moreover, emerge dynamically from the instability of the former, also exist.publishe

Steady State Behavior of Mechanically Perturbed Spin Glasses and Ferromagnets

A zero temperature dynamics of Ising spin glasses and ferromagnets on random graphs of finite connectivity is considered, like granular media these systems have an extensive entropy of metastable states. We consider the problem of what energy a randomly prepared spin system falls to before becoming stuck in a metastable state. We then introduce a tapping mechanism, analogous to that of real experiments on granular media, this tapping, corresponding to flipping simultaneously any spin with probability $p$, leads to stationary regime with a steady state energy $E(p)$. We explicitly solve this problem for the one dimensional ferromagnet and $\pm J$ spin glass and carry out extensive numerical simulations for spin systems of higher connectivity. The link with the density of metastable states at fixed energy and the idea of Edwards that one may construct a thermodynamics with a flat measure over metastable states is discussed. In addition our simulations on the ferromagnetic systems reveal a novel first order transition, whereas the usual thermodynamic transition on these graphs is second order.Comment: 11 pages, 7 figure

A counterintuitive way to speed up pedestrian and granular bottleneck flows prone to clogging: can 'more' escape faster?

Dense granular flows through constrictions, as well as competitivepedestrian evacuations, are hindered by a propensity to form clogs. We use simulations of model pedestrians and experiments with granular disks to explore an original strategy to speed up these flows, which consists in including contact-averse entities in the assembly. On the basis of a minimal cellular automaton and a continuous agent-based model for pedestrian evacuation dynamics, we find that the inclusion of polite pedestrians amid a given competitive crowd fails to reduce the evacuation time when the constriction (the doorway) is acceptably large. This is not surprising, because adding agents makes the crowd larger. In contrast, when the door is so narrow that it can accommodate at most one or two agents at a time, our strategy succeeds in substantially curbing long-lived clogs and speeding up the evacuation. A similar eect is seen experimentally in a vibrated two-dimensional hopper flow with an opening narrower than 3 disk diameters. Indeed, by adding to the initial collection of neutral disks a large fraction of magnetic ones, interacting repulsively, we observe a shortening of the time intervals between successive egresses of neutral disks, as reflected by the study of their probability distribution. On a more qualitative note, our study suggests that the much discussed analogy between pedestrian flows and granular flows could be extended to some behavioural traits of individualpedestrians.Fil: Nicolas, Alexandre. Université Paris Sud; Francia. Centre National de la Recherche Scientifique; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ibáñez, Santiago Agustín. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Universidad Nacional de Río Negro. Sede Andina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kuperman, Marcelo Nestor. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Universidad Nacional de Río Negro. Sede Andina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bouzat, Sebastian. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Universidad Nacional de Río Negro. Sede Andina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin