1,315 research outputs found
Nonlocality in many-body quantum systems detected with two-body correlators
Contemporary understanding of correlations in quantum many-body systems and
in quantum phase transitions is based to a large extent on the recent intensive
studies of entanglement in many-body systems. In contrast, much less is known
about the role of quantum nonlocality in these systems, mostly because the
available multipartite Bell inequalities involve high-order correlations among
many particles, which are hard to access theoretically, and even harder
experimentally. Standard, "theorist- and experimentalist-friendly" many-body
observables involve correlations among only few (one, two, rarely three...)
particles. Typically, there is no multipartite Bell inequality for this
scenario based on such low-order correlations. Recently, however, we have
succeeded in constructing multipartite Bell inequalities that involve two- and
one-body correlations only, and showed how they revealed the nonlocality in
many-body systems relevant for nuclear and atomic physics [Science 344, 1256
(2014)]. With the present contribution we continue our work on this problem. On
the one hand, we present a detailed derivation of the above Bell inequalities,
pertaining to permutation symmetry among the involved parties. On the other
hand, we present a couple of new results concerning such Bell inequalities.
First, we characterize their tightness. We then discuss maximal quantum
violations of these inequalities in the general case, and their scaling with
the number of parties. Moreover, we provide new classes of two-body Bell
inequalities which reveal nonlocality of the Dicke states---ground states of
physically relevant and experimentally realizable Hamiltonians. Finally, we
shortly discuss various scenarios for nonlocality detection in mesoscopic
systems of trapped ions or atoms, and by atoms trapped in the vicinity of
designed nanostructures.Comment: 46 pages (25.2 + appendices), 7 figure
Editorial: Teaching history in the era of globalization: epistemological and methodological challenges
The COVID-19 pandemic has highlighted the need of several changes within the field of History Education. Firstly, the need of a methodological change that integrates active learning methods, digital resources, and emerging technologies in order to attend the non-presential lessons for the students. Secondly, the need of a multicultural approach on teaching history, social, and gender equality moving away from supremacists' dogma. It is necessary for teachers to change their conception of why and for what reasons they teach history. This need has become more acute with the COVID-19 pandemic: fighting vs. hate speeches through argumentation and critical analysis of sources to avoid fake news and to develop a learning perception evidences. This Research Topic is focused both on Primary and Secondary Education, but also on Higher Education, considering History teachers training courses. Particularly, this book focuses to know the development of the skills of active and future History teachers who are trained at programs at universities to bring a profound methodological and content change in the way History is taught..
Characterization of the Hamamatsu R11410-10 3-Inch Photomultiplier Tube for Liquid Xenon Dark Matter Direct Detection Experiments
To satisfy the requirements of the next generation of dark matter detectors
based on the dual phase TPC, Hamamatsu, in close collaboration with UCLA, has
developed the R11410-10 photomultipler tube. In this work, we present the
detailed tests performed on this device. High QE (>30%) accompanied by a low
dark count rate (50 Hz at 0.3 PE) and high gain (10^7) with good single PE
resolution have been observed. A comprehensive screening measurement campaign
is ongoing while the manufacturer quotes a radioactivity of 20 mBq/PMT. These
characteristics show the R11410-10 to be particularly suitable for the
forthcoming zero background liquid xenon detectors.Comment: 19 pages, 18 figure
Scattering polarization of hydrogen lines from electric-induced atomic alignment
We consider a gas of hydrogen atoms illuminated by a broadband, unpolarized
radiation with zero anisotropy. In the absence of external fields, the atomic
J-levels are thus isotropically populated. While this condition persists in the
presence of a magnetic field, we show instead that electric fields can induce
the alignment of those levels. We also show that this electric alignment cannot
occur in a two-term model of hydrogen (e.g., if only the Ly-alpha transition is
excited), or if the level populations are distributed according to Boltzmann's
law.Comment: 10 pages, 4 figures. Accepted by J.Phys.B: At.Mol.Opt.Phy
Endovascular treatment for acute basilar artery occlusion: Descriptive analysis of the experience in a comprehensive stroke centre
Objectives: To describe the clinical and epidemiological characteristics of patients with basilar artery occlusion (BAO) treated with mechanical thrombectomy (MT) in Aragón, and to compare its anaesthetic management, technical effectivity, security, and prognosis with those of anterior circulation. Methods: 322 patients from the prospective registry of mechanical thrombectomies from Aragon were assessed: 29 with BAO and 293 with an anterior circulation large vessel occlusion. Baseline characteristics, procedural, clinical and safety outcomes variables were compared. Results: Out of 29 patients with BAO that underwent endovascular therapy (62.1% men; average age 69.8 ± 14.05 years) 18 (62.1%) received endovascular therapy (EVT) alone and 11 (37.9%) EVT plus intravenous thrombolysis. Atherothrombotic stroke was the most common etiology (41%). The BAO group had longer Door-to-groin (160 vs 141 min; P = 0.043) and Onset-to-reperfusion times (340 vs 297 min; P = 0.005), and higher use of general anaesthesia (60.7% vs 14.7%; P < 0.01). No statistically significant difference was found for Procedure time (60 vs 50 min; P = 0.231) nor the rate of successful recanalization (72.4% vs 82.7%; P = 0.171). Functional independence at 90 days was significantly worse in the BAO group (17.9% vs 38.2%; P < 0.01). Conclusions: Patients with basilar artery occlusion had higher morbimortality despite similar angiographic results. Mechanical thrombectomy for BAOs is a safe and effective procedure in selected patients. A consensus about the effect of anaesthesia has yet to be reached, for BAO general anaesthesia remains the most frequently used technique
Correction to: Wnt3a induces exosome secretion from primary cultured rat microglia
Correction to: BMC Neuroscience 2012, 13:144 http://www.biomedcentral.com/1471-2202/13/14
O Processo de coloração a seco de porcelanato. Parte 1: Variáveis envolvidas e influência sobre as propriedades das peças
Dentre as tipologias de revestimentos cerâmicos atualmente produzidos o porcelanato tem se destacado pela grande expansão em sua produção, observada nos últimos anos. O sucesso do produto se deve pelas propriedades técnicas e estéticas oferecidas. Dentro deste contexto a técnica de coloração a seco surge como alternativa a ser adotada no processamento da massa do material, pois confere ao produto características estéticas que podem ser obtidas através de uma simples mistura de pigmentos e grânulos atomizados. Entretanto, pouco se conhece sobre as variáveis envolvidas neste processo de mistura e a real interferência de cada uma delas nas propriedades apresentadas pelo produto queimado. Este trabalho apresenta o resultado de um estudo que revela o efeito das principais variáveis relacionadas à mistura do pigmento com os grânulos atomizados sobre as propriedades apresentadas pelo produto fina
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