7,317 research outputs found
Neutrino and antineutrino quasielastic interactions with nuclei
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
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
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 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
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
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
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
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
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
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
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
- …