7,317 research outputs found

    Neutrino and antineutrino quasielastic interactions with nuclei

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    We investigate the interaction of neutrinos and antineutrinos with nuclei. We explore in particular the role played by the multinucleon excitations which can contaminate the quasielastic cross section. For neutrinos the multinucleon term produces a sizable increase of the quasielastic cross section. Part of the effect arises from tensor correlations. For antineutrinos this influence is smaller owing to the axial-vector interference which increases the relative importance of the terms which are not affected by these multinucleon excitations

    Multiparticle Quantum Superposition and Stimulated Entanglement by Parity Selective Amplification of Entangled States

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    A multiparticle quantum superposition state has been generated by a novel phase-selective parametric amplifier of an entangled two-photon state. This realization is expected to open a new field of investigations on the persistence of the validity of the standard quantum theory for systems of increasing complexity, in a quasi decoherence-free environment. Because of its nonlocal structure the new system is expected to play a relevant role in the modern endeavor on quantum information and in the basic physics of entanglement.Comment: 13 pages and 3 figure

    Complete and Deterministic discrimination of polarization Bell state assisted by momentum entanglement

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    A complete and deterministic Bell state measurement was realized by a simple linear optics experimental scheme which adopts 2-photon polarization-momentum hyperentanglement. The scheme, which is based on the discrimination among the single photon Bell states of the hyperentangled state, requires the adoption of standard single photon detectors. The four polarization Bell states have been measured with average fidelity F=0.889±0.010F=0.889\pm0.010 by using the linear momentum degree of freedom as the ancilla. The feasibility of the scheme has been characterized as a function of the purity of momentum entanglement.Comment: 4 pages, v2, comments adde

    Continuous variable cloning via network of parametric gates

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    We propose an experimental scheme for the cloning machine of continuous quantum variables through a network of parametric amplifiers working as input-output four-port gates.Comment: 4 pages, 2 figures. To appear on Phys. Rev. Let

    Neutrino interactions with nuclei

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    We present a model for neutrino-nucleus scattering in the energy region relevant for present and forthcoming neutrino-oscillation experiments. The model is based on the RPA treatment of the nuclear responses in the quasi-elastic and Delta-resonance region. It includes also in a phenomenological way nucleon knock-out. It aims at the description, within a single framework, of several final state channels i.e. quasi-elastic, incoherent and coherent one-pion production and two- or several-nucleon knock-out.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

    Architectural approaches to build the Museum of the Person

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    The Museum of the Person (Museu da Pessoa, MP) is a virtual museum aimed at exhibiting life stories of common people. Its assets are composed of several interviews involving people whose stories we want to perpetuate. So the museum holds an heterogeneous collection of XML (eXtensible Markup Language) documents that constitute the working repository. The main idea is to extract automatically the information included in the repository in order to build the web pages that realize the museum's exhibition rooms. This project started by creating a specific ontology (OntoMP) for the knowledge repository of MP. That ontology is intended to allow a conceptual navigation over the available information. We will adopt the standard for museum ontologies CIDOC-CRM (CIDOC Conceptual Reference Model) refined with FOAF to represent OntoMP. The objective of this paper is to discuss different architectural approaches to build a system that will create the virtual rooms from the XML repository to enable visitors to lookup individual life stories and also intercross information among them. The first architecture is based on a TripleStore and uses SPARQL (SPARQL Protocol and RDF Query Language) technology to extract the information, while the second proposal is based on a Relational Database and uses CaVa Generator to query the repository and build the exhibition spaces.info:eu-repo/semantics/publishedVersio

    OntoMP, an ontology to build the museum of the person

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    This paper is concerned with the creation of a specific ontology for the knowledge repository of the Museum of the Person (Museu da Pessoa). The Museum of the Person assets are composed of several interviews (collected previously for a large cultural project) involving common people, to perpetuate their life stories. The museum holds an heterogeneous collection of XML documents. In such format, the collection items are many times not recognizable and understandable by the visitors who wish to explore it. Therefore, we intend to use an ontology that allows a conceptual navigation over the available information, enabling the visitors to extract knowledge during the visit to these life stories. So, this paper aims at presenting the ontology we have developed using CIDOC Conceptual Reference Model (CIDOC-CRM)[1] to enable visitors to lookup individual life stories, read them, and also intercross information among a cluster of life stories to build up the story of a company/institution or to study social behaviors and customs.This work has been supported by FCT - Fundacao para a Ciencia e Tecnologia within the Project Scope: UID/CEC/00319/2013. The work of Ricardo G. Martini is supported by CNPq, grant 201772/2014-0.info:eu-repo/semantics/publishedVersio

    Quaternionic spherical harmonics and a sharp multiplier theorem on quaternionic spheres

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    A sharp Lp spectral multiplier theorem of Mihlin–Hörmander type is proved for a distinguished sub-Laplacian on quaternionic spheres. This is the first such result on compact sub-Riemannian manifolds where the horizontal space has corank greater than one. The proof hinges on the analysis of the quaternionic spherical harmonic decomposition, of which we present an elementary derivation

    Superscaling in electroweak excitation of nuclei

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    Superscaling properties of 12C, 16O and 40Ca nuclear responses, induced by electron and neutrino scattering, are studied for momentum transfer values between 300 and 700 MeV/c. We have defined two indexes to have quantitative estimates of the scaling quality. We have analyzed experimental responses to get the empirical values of the two indexes. We have then investigated the effects of finite dimensions, collective excitations, meson exchange currents, short-range correlations and final state interactions. These effects strongly modify the relativistic Fermi gas scaling functions, but they conserve the scaling properties. We used the scaling functions to predict electron and neutrino cross sections and we tested their validity by comparing them with the cross sections obtained with a full calculation. For electron scattering we also made a comparison with data. We have calculated the total charge-exchange neutrino cross sections for neutrino energies up to 300 MeV.Comment: 19 pages, 12 figures, 1 table; to be published in Physical Review

    Pre-discovery and Follow-up Observations of the Nearby SN 2009nr: Implications for Prompt Type Ia SNe

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    We present photometric and spectroscopic observations of the Type Ia supernova SN 2009nr in UGC 8255 (z=0.0122). Following the discovery announcement at what turned out to be ten days after peak, we detected it at V ~15.7 mag in data collected by the All Sky Automated Survey (ASAS) North telescope 2 weeks prior to the peak, and then followed it up with telescopes ranging in aperture from 10-cm to 6.5-m. Using early photometric data available only from ASAS, we find that the SN is similar to the over-luminous Type Ia SN 1991T, with a peak at Mv=-19.6 mag, and a slow decline rate of Dm_15(B)=0.95 mag. The early post-maximum spectra closely resemble those of SN 1991T, while the late time spectra are more similar to those of normal Type Ia SNe. Interestingly, SN 2009nr has a projected distance of 13.0 kpc (~4.3 disk scale lengths) from the nucleus of the small star-forming host galaxy UGC 8255. This indicates that the progenitor of SN 2009nr is not associated with a young stellar population, calling into question the conventional association of luminous SNe Ia with the "prompt" component directly correlated with current star formation. The pre-discovery observation of SN 2009nr using ASAS demonstrates the science utility of high cadence all sky surveys conducted using small telescopes for the discovery of nearby (d=<50 Mpc) supernovae.Comment: 11 pages, 11 figures, 4 tables. Accepted for publication in ApJ on 11/02/201
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