5,209 research outputs found

    Evolution of quantum observables: from non-commutativity to commutativity

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    A fundamental aspect of the quantum-to-classical limit is the transition from a non- commutative algebra of observables to commutative one.However, this transition is not possible if we only consider unitary evolutions. One way to describe this transition is to consider the Gamow vectors, which introduce exponential decays in the evolution. In this paper, we give two mathematical models in which this transition happens in the infinite time limit. In the first one, we consider operators acting on the space of the Gamow vectors, which represent quantum resonances. In the second one, we use an algebraic formalism from scattering theory. We construct a non-commuting algebra which commutes in the infinite time limit.MINECO Grant MTM2014- 57129-C2-1-P. Junta de Castilla y Leon Grants BU229P18, VA137G18

    Neutrinos in the simplest little Higgs scenario and TeV leptogenesis

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    The little Higgs scenario may provide an interesting framework to accommodate TeV scale leptogenesis because a TeV Majorana mass of the right-handed neutrino that we employ for the latter may find a natural place near the ultraviolet cutoff of the former. In this work we study how a light neutrino spectrum, generated radiatively, and TeV scale leptogenesis can be embedded in the simplest little Higgs framework. Alternatively, we highlight how the neutrino Yukawa textures of the latter are constrained.Comment: 10 pages, latex, v2: refs and comments added, to appear in PR

    Ammoniakemissie en emissiereductie van het balansballensysteem bij vleesvarkens

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    This research was conducted to measure the effect of the “balansballen” system, with and without VevoVitall®, on the ammonia emission from growing-finishing pigs housed in partly slatted pens that were fully equipped with a manure pit underneath. These emissions were compared to a reference system (without VevoVitall® and without the “balansballen” system) in order to determine the emission reduction of both treatments. The measurements were performed according to the measurement protocol “Ammonia emission from animal houses 2007”

    Symmetry Nonrestoration at High Temperature in Little Higgs Models

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    A detailed study of the high temperature dynamics of the scalar sector of Little Higgs scenarios, proposed to stabilize the electroweak scale, shows that the electroweak gauge symmetry remains broken even at temperatures much larger than the electroweak scale. Although we give explicit results for a particular modification of the Littlest Higgs model, we expect that the main features are generic. As a spin-off, we introduce a novel way of dealing with scalar fluctuations in nonlinear sigma models, which might be of interest for phenomenological applications.Comment: 23 pages, LaTeX, 4 figure

    Semantic Web-enabled Protocol Mediation for the Logistics Domain

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    Among the problems that arise when trying to make different applications interoperate with each other, protocol mediation is one of the most difficult ones and for which less relevant literature can be found. Protocol mediation is concerned with non-matching message interaction patterns in application interaction. In this paper we describe the design and implementation of a protocol mediation component that has been applied in the interoperation between two heterogeneous logistic provider systems (using two different standards: RosettaNet and EDIFACT), for a specific freight forwarding task

    Leptogenesis beyond the limit of hierarchical heavy neutrino masses

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    We calculate the baryon asymmetry of the Universe in thermal leptogenesis beyond the usual lightest right-handed (RH) neutrino dominated scenario (N_1DS) and in particular beyond the hierarchical limit (HL), M_1 << M_2 << M_3, for the RH neutrino mass spectrum. After providing some orientation among the large variety of models, we first revisit the central role of the N_1DS, with new insights on the dynamics of the asymmetry generation and then discuss the main routes departing from it, focusing on models beyond the HL. We study in detail two examples of `strong-strong' wash-out scenarios: one with `maximal phase' and the limit of very large M_3, studying the effects arising when delta_2=(M_2-M_1)/M_1 is small. We extend analytical methods already applied to the N_1DS showing, for example, that, in the degenerate limit (DL), the efficiency factors of the RH neutrinos become equal with the single decay parameter replaced by the sum. Both cases disprove the misconception that close RH neutrino masses necessarily lead to a final asymmetry enhancement and to a relaxation of the lower bounds on M_1 and on the initial temperature of the radiation-dominated expansion. We also explain why leptogenesis tends to favor normal hierarchy compared to inverted hierarchy for the left-handed neutrino masses.Comment: 30 pages, 8 figures; corrected typo in Eq. (67); shortened Introduction, Section 3 and Conclusions; one figure removed; added 2 references; to appear in JCA

    Personal eBanking Solutions Based on Semantic Web Services

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    We describe how Semantic Web Service technology can be used for the provision of personal e-banking online services. We describe two deployed applications: an overdraft notification service and a mortgage comparison service. The former accesses the bank accounts of a user as well as utility goods Web sites where invoicing information is stored and estimates whether the user will be in an overdraft situation in the near future, alerting him/her by e-mail or SMS. The latter accesses the mortgage information provided by the heterogeneous Web sites of different banks and allows users to compare them according to different types of criteria. The chapter not only focuses on the technological decisions followed to implement and deploy these services, but also on the added value of applying Semantic Web Services for them
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