Vertex Intrinsic Fitness: How to Produce Arbitrary Scale-Free Networks

We study a recent model of random networks based on the presence of an intrinsic character of the vertices called fitness. The vertices fitnesses are drawn from a given probability distribution density. The edges between pair of vertices are drawn according to a linking probability function depending on the fitnesses of the two vertices involved. We study here different choices for the probability distribution densities and the linking functions. We find that, irrespective of the particular choices, the generation of scale-free networks is straightforward. We then derive the general conditions under which scale-free behavior appears. This model could then represent a possible explanation for the ubiquity and robustness of such structures.Comment: 4 pages, 3 figures, RevTe

MiniBooNE

The physics motivations, design, and status of the Booster Neutrino Experiment at Fermilab, MiniBooNE, are briefly discussed. Particular emphasis is given on the ongoing preparatory work that is needed for the MiniBooNE muon neutrino to electron neutrino oscillation appearance search. This search aims to confirm or refute in a definitive and independent way the evidence for neutrino oscillations reported by the LSND experiment.Comment: 3 pages, no figures, to appear in the proceedings of the 9th International Conference on Astroparticle and Underground Physics (TAUP 2005), Zaragoza, Spain, 10-14 Sep 200

Narrow Linewidth 780 nm Distributed Feedback Lasers for Cold Atom Quantum Technology

Cold atom quantum technology systems have a wide range of potential applications which includes atomic clocks, rotational sensors, inertial sensors, quantum navigators, magnetometers and gravimeters. The UK Quantum Technology Hub in Sensors and Metrology has the aim of developing miniature cold atom systems using an approach similar to that pioneered by the chip scale atomic clock where microfabricated vacuum chambers have atomic transitions excited and probed by lasers. Whilst narrow linewidth Ti:Sa and external cavity diode lasers have been required for cooling and control, such lasers are too large, power hungry and expensive for future miniature cold atom systems. Here we demonstrate 1 mm long 780.24 nm GaAs/AlGaAs distributed feedback (DFB) lasers aimed at 87Rb cold atom systems operating at 20 ˚C with over 50 mW of power and side-mode suppression ratios of 46 dB using sidewall gratings and no regrowth. Rb spectroscopy is used to demonstrate linewidths below the required 6.07 MHz natural linewidth of the 87Rb D2 optical transition used for cooling. Initial packaged fibre-coupled devices demonstrate lifetimes greater than 200 hours. We also investigate the use of integrated semiconductor amplifiers (SOAs) and longer devices to further reduce the linewidths well below 1 MHz. A range of options to control the populations of electrons in the hyperfine split energy levels spaced by 3.417 GHz are examined. Two integrated lasers, integrated electro-absorption modulators (EAMs) and the direct modulation of a single DFB laser approaches are investigated and we will discuss which is best suited to integrated cold atom systems

Realization of quantum walks with negligible decoherence in waveguide lattices

Quantum random walks are the quantum counterpart of classical random walks, and were recently studied in the context of quantum computation. Physical implementations of quantum walks have only been made in very small scale systems severely limited by decoherence. Here we show that the propagation of photons in waveguide lattices, which have been studied extensively in recent years, are essentially an implementation of quantum walks. Since waveguide lattices are easily constructed at large scales and display negligible decoherence, they can serve as an ideal and versatile experimental playground for the study of quantum walks and quantum algorithms. We experimentally observe quantum walks in large systems (similar to 100 sites) and confirm quantum walks effects which were studied theoretically, including ballistic propagation, disorder, and boundary related effects

Nuclear effects in electron reactions and their impact on neutrino processes

We suggest that superscaling in electroweak interactions with nuclei, namely the observation that the reduced electron-nucleus cross sections are to a large degree independent of the momentum transfer and of the nuclear species, can be used as a tool to obtain precise predictions for neutrino-nucleus cross sections in both charged and neutral current-induced processes.Comment: 11 pages, 7 figures, proceedings of NUINT09, 6th International Workshop of Neutrino-Nucleus Interactions in the Few-Gev Region, Sitges (Spain), May 18-22, 200

Neutrino Interactions Importance for Nuclear Physics

We review the general interplay between Nuclear Physics and neutrino-nucleus cross sections at intermediate and high energies. The effects of different reaction mechanisms over the neutrino observables are illustrated with examples in calculations using several nuclear models and ingredients.Comment: To appear in the proceedings of 6th International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region (NuInt09), Sitges, Spain, 18 - 22 May 200

VLSI implementation of the edge sampling using a conditionned data flow specification

The paper presents a novel approach to automatically synthesize a VLSI circuit implementing an algorithm specified and verified with a conditionned data flow graph . An edge sampling algorithm, classically used in image processing, is taken to experimen t the approach. It is specified and verified with the conditionned data flow language SIGNAL. This allows to produce easily, using straitforward rules, the digital logic diagram, which will be exploited by an automatic synthesis CAD software to produce a VLSI circuit.Cet article présente une nouvelle approche permettant de synthétiser automatiquement le circuit VLSI implantant un algorithme spécifié et vérifié avec un graphe flot de données conditionné. Un algorithme d'échantillonnage de contour, classique en traitement d'images, est utilisé comme exemple pour illustrer l'approche. On le spécifie et on le vérifie avec le langage synchrone flot de données conditionné SIGNAL afin de produire directement, en utilisant des règles simples, le schéma logique correspondant. Ce dernier servira d'entrée à un logiciel de CAO de synthèse automatique de circuit, pour produire un circuit VLSI