Extended Bose-Hubbard models with Rydberg macrodimer dressing

Extended Hubbard models have proven to bear novel quantum states, but their experimental realization remains challenging. In this work we propose to use bosonic quantum gases dressed with molecular bound states in Rydberg interaction potentials for the observation of these quantum states. We study the molecular Rabi coupling with respect to principal quantum number and trapping frequency of the ground state atoms for various molecular potentials of Rubidium and Potassium, and the hereby resulting dressed interaction strength. Additionally, we propose a two-color excitation scheme which significantly increases the dressed interaction and cancels AC Stark shifts limiting the atomic motion in the itinerant regime. We study the various equilibrium phases of the corresponding extended Bose-Hubbard model by means of the Cluster Gutzwiller approach and perform time evolution simulations via the Lindblad master equation. We find a supersolid phase by slowly ramping the molecular Rabi coupling of an initially prepared superfluid and discuss the role of dissipation.Comment: 11 pages, 7 figure

Le métier de chef de projet comme activité prudentielle.

Si la gestion de projet est une activité désormais répandue dans les entreprises, le contenu du travail qu’elle implique reste paradoxalement mal connu. En s’appuyant sur une enquête menée auprès de chefs de projet d’un groupe industriel et sur les catégories de l’activité « prudentielle » proposées par Florent Champy, cet article rend intelligible ce contenu. Il montre que le chef de projet adopte un regard global sur son projet, surveille les contingences pouvant nuire à son déroulement et mobilise un « sens du possible » pour résoudre les problèmes auxquels il est confronté et arbitrer entre des exigences contradictoires. Le lien de subordination inhérent à son statut de salarié contraint son autonomie, mais lui procure aussi un certain nombre d’appuis organisationnels confortant la construction de sa vision globale du projet, de sa vigilance et de son sens du possible : la prudence apparaît sous la forme d’une qualité distribuée dans un réseau étroit de dispositifs organisationnels.The paper, based on a survey conducted with project managers of an industrial group, sheds light on the effective content of project management. Indeed, whereas this task has a real social visibility, its content is not well known. This text mobilizes the categories of “prudential activity” put forward by Florent Champy and shows that the project manager adopts a global view of his project, monitors the contingencies that may impede project progress, uses both his intuition and his experience to solve his problems and to arbitrate between conflicting requirements. The relationship of subordination that results from his status as an employee limits his autonomy, but also gives him organizational supports that consolidate his global view, his vigilance, and his intuition: prudence appears as a quality shared out within a narrow network of organizational devices

Evaluation of kernel low-rank compressed sensing in preclinical diffusion magnetic resonance imaging

Compressed sensing (CS) is widely used to accelerate clinical diffusion MRI acquisitions, but it is not widely used in preclinical settings yet. In this study, we optimized and compared several CS reconstruction methods for diffusion imaging. Different undersampling patterns and two reconstruction approaches were evaluated: conventional CS, based on Berkeley Advanced Reconstruction Toolbox (BART-CS) toolbox, and a new kernel low-rank (KLR)-CS, based on kernel principal component analysis and low-resolution-phase (LRP) maps. 3D CS acquisitions were performed at 9.4T using a 4-element cryocoil on mice (wild type and a MAP6 knockout). Comparison metrics were error and structural similarity index measure (SSIM) on fractional anisotropy (FA) and mean diffusivity (MD), as well as reconstructions of the anterior commissure and fornix. Acceleration factors (AF) up to 6 were considered. In the case of retrospective undersampling, the proposed KLR-CS outperformed BART-CS up to AF = 6 for FA and MD maps and tractography. For instance, for AF = 4, the maximum errors were, respectively, 8.0% for BART-CS and 4.9% for KLR-CS, considering both FA and MD in the corpus callosum. Regarding undersampled acquisitions, these maximum errors became, respectively, 10.5% for BART-CS and 7.0% for KLR-CS. This difference between simulations and acquisitions arose mainly from repetition noise, but also from differences in resonance frequency drift, signal-to-noise ratio, and in reconstruction noise. Despite this increased error, fully sampled and AF = 2 yielded comparable results for FA, MD and tractography, and AF = 4 showed minor faults. Altogether, KLR-CS based on LRP maps seems a robust approach to accelerate preclinical diffusion MRI and thereby limit the effect of the frequency drift

Functional Discretization of Space Using Gaussian Processes for Road Intersection

International audienceThis paper propose a new framework to discretize the space within and around a cross intersection. The main purpose of our approach is to capture the manner in which drivers manoeuvre in an intersection in order to facilitate and understand the decision-making tasks. Gaussian processes are used to learn and predict the most likely trajectories taken by multiple drivers in different situations. The merging and crossing areas are found by searching for the overlap between two predicted trajectories, whereas the area approaching the intersection is discretized by using the most probable occupancy. The generated areas are stored in a map. It was possible to show the correlation between this discretization and the drivers’ behaviour by looking at how the proposed framework also discretizes the velocity profile, which can then be applied to decision making

Probabilistic Decision-Making at Road Intersections: Formulation and Quantitative Evaluation

International audienceAs drivers approach a road intersection, they must decide whether to cross it or to come to a stop. For this purpose, drivers make a situation assessment and adapt their behaviour accordingly. When this task is performed by a computer, the available information is partial and uncertain. Any decision requires the system to use this information as well as taking into account the behaviour of other drivers to avoid collisions. However, metrics such as collision rate can remain low in an interactive environment because of other driver’s actions. Consequently, evaluation metrics must depend on other driving aspects. In this paper a decision-making mechanism and metrics to evaluate such a system at road intersection crossing are presented. For the former, a Partially Observable Markov Decision Process is used to model the system with respect to uncertainties in the behaviour of other drivers. For the latter, different key performance indicators are defined to evaluate the resulting behaviour of the system with different configurations and scenarios. The approach is demonstrated within an automotive grade simulator. It has showed at times, that whilst the vehicle can cross safely the intersection, it might not satisfy other key performance indicators related to highway code

CD1 Gene Polymorphisms and Phenotypic Variability in X-Linked Adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is characterized by marked phenotypic variation ranging from adrenomyeloneuropathy (AMN) to childhood cerebral ALD (CCALD). X-ALD is caused by mutations in the ABCD1 gene, but no genotype-phenotype correlation has been established so far and modifier gene variants are suspected to modulate phenotypes. Specific classes of lipids, enriched in very long-chain fatty acids that accumulate in plasma and tissues from X-ALD patients are suspected to be involved in the neuroinflammatory process of CCALD. CD1 proteins are lipid- antigen presenting molecules encoded by five CD1 genes in human (CD1A-E). Association studies with 23 tag SNPs covering the CD1 locus was performed in 52 patients with AMN and 87 patients with CCALD. The minor allele of rs973742 located 4-kb downstream from CD1D was significantly more frequent in AMN patients (χ2 = 7.6; P = 0.006). However, this association was no longer significant after Bonferroni correction for multiple testing. The other polymorphisms of the CD1 locus did not reveal significant association. Further analysis of other CD1D polymorphisms did not detect stronger association with X-ALD phenotypes. Although the association with rs973742 warrants further investigations, these results indicate that the genetic variants of CD1 genes do not contribute markedly to the phenotypic variance of X-ALD

Evaluating the Potential of Commercial Forest Inventory Data to Report on Forest Carbon Stock and Forest Carbon Stock Changes for REDD+ under the UNFCCC

In the context of the adoption at the 16th Conference of the Parties in 2010 on the REDD+ mitigation mechanism, it is important to obtain reliable data on the spatiotemporal variation of forest carbon stocks and changes (called Emission Factor, EF). A re-occurring debate in estimating EF for REDD+ is the use of existing field measurement data. We provide an assessment of the use of commercial logging inventory data and ecological data to estimate a conservative EF (REDD+ phase 2) or to report on EF following IPCC Guidance and Guidelines (REDD+ phase 3). The data presented originate from five logging companies dispersed over Gabon, totalling 2,240 plots of 0.3 hectares.We distinguish three Forest Types (FTs) in the dataset based on floristic conditions. Estimated mean aboveground biomass (AGB) in the FTs ranges from 312 to 333 Mg ha-1. A 5% accuracy is reached with the number of plots put in place for the FTs and a low sampling uncertainty obtained (± 10 to 13 Mg ha-1). The data could be used to estimate a conservative EF in REDD+ phase 2 and only partially to report on EF following tier 2 requirements for a phase 3