650 research outputs found

    Valencian Reconquest churches. Study of the archaeological remains found in the Algemesí Capilla de la Comunión.

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    [EN] The present paper deals with the examination and research to the vestiges of an ancient church discovered in the basement of the Algemesi Communion Chapel, dating back to the beginnings of Christianity in the city. Considering the disposition of the constructive elements and the documented historical facts that date back to the first parish in the 13th century, it was deduced that the remains found were part of a temple with diaphragmatic arches and a woody roof. These facts are the paradigm of the ecclesiastical architecture that prevailed, by its execution speed, in the kingdom of Valencia after Jaime I reconquest. The study includes the comparison with other buildings of the same nature that allowed reconstructing its hypothetical volume, as well as the analysis of the techniques and materials that shaped its structure. Its identification ascribes another example to the Valencian protogothic architecture.García Sentamans, J.; Fernández-Plazaola, I.; Ferrandis Montesinos, JV.; Sáez Landete, A. (2019). Valencian Reconquest churches. Study of the archaeological remains found in the Algemesí Capilla de la Comunión. Architecture Civil Engineering Environment. 12(4):37-50. https://doi.org/10.21307/ACEE-2019-050S375012

    Recovery and musealization of war trenches

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    [EN] At a time of incresing popularity of the war heritage of the province of Teruel, the coordination between different territorial administrations and the establishment of common guidelines is more necessary than ever to lead interventions in this type of sites. The work carried out in the positions of Santa Bárbara and Loma de Casares in Celadas (Teruel) are an example of how the authors understand that the conservation and enhancement of the vestiges of the Spanish Civil War should be approached, in which difficulties such as access to the position, great extension, poor workmanship and an advanced state of abandonment and deterioration converge. This work also illustrates the integral and interdisciplinary character recommended in this type of projects, which addresses the historical documentation, the interpretation of the position and the delimitation of the intervention areas, the work of archaeological excavation, the adequacy of accesses, and even signaling, promotion and tourist diffusion.[ES] En un momento en el que el patrimonio bélico de la provincia de Teruel goza de una popularidad creciente, se hace más necesario que nunca la coordinación entre las distintas administraciones territoriales y el establecimiento de unas directrices comunes que guíen las intervenciones en este tipo de enclaves. Los trabajos realizados en las posiciones de Santa Bárbara y Loma de Casares en Celadas (Teruel) son un ejemplo de cómo los autores entienden que deben abordarse la conservación y puesta en valor de los vestigios de la guerra civil española, en los que confluyen dificultades como el acceso al enclave, su gran extensión, una pobre factura y un avanzado estado de abandono y deterioro. En este trabajo también se ilustra el carácter integral e interdisciplinar que se recomienda en este tipo de proyectos, y que aborda desde la documentación histórica, la interpretación de la posición y la delimitación de las zonas de intervención, hasta las labores de excavación arqueológica, adecuación de accesos, señalización, promoción y difusión turística.García Enguita, A.; Ibáñez González, J.; Sáez Abad, R.; Villalba Alegre, I. (2023). Recuperación y musealización de trincheras de guerra. Loggia, Arquitectura & Restauración. (36):92-105. https://doi.org/10.4995/loggia.2023.19983921053

    Photon statistics in collective strong coupling: Nanocavities and microcavities

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    There exists a growing interest in the properties of the light generated by hybrid systems involving a mesoscopic number of emitters as a means of providing macroscopic quantum light sources. In this work, the quantum correlations of the light emitted by a collection of emitters coupled to a generic optical cavity are studied theoretically using an effective Hamiltonian approach. Starting from the single-emitter level, we analyze the persistence of photon antibunching as the ensemble size increases. Not only is the photon blockade effect identifiable, but photon antibunching originated from destructive interference processes, the so-called unconventional antibunching, is also present. We study the dependence of these two types of negative correlations on the spectral detuning between cavity and emitters, as well as its evolution as the time delay between photon detections increases. Throughout this work, the performance of plasmonic nanocavities and dielectric microcavities is compared: despite the distinct energy scales and the differences introduced by their respectively open and closed character, the bunching and antibunching phenomenology presents remarkable similarities in both types of cavitiesThis work has been funded by the European Research Council under Grant Agreements No. ERC-2011-AdG 290981 and No. ERC-2016-STG-714870, the EU Seventh Framework Programme (Grants No. FP7-PEOPLE-2013-CIG-630996 and No. FP7-PEOPLE-2013-CIG-618229), and the Spanish MINECO under Contracts No. MAT2014-53432-C5-5-R and No. FIS2015-64951-R, as well as through the “María de Maeztu” programme for Units of Excellence in R&D (Grant No. MDM-2014-0377)

    Organic polaritons enable local vibrations to drive long-range energy transfer

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    Long-range energy transfer in organic molecules has been experimentally obtained by strongly coupling their electronic excitations to a confined electromagnetic cavity mode. Here, we shed light into the polariton-mediated mechanism behind this process for different configurations: donor and acceptor molecules either intermixed or physically separated. We numerically address the phenomenon by means of Bloch-Redfield theory, which allows us to reproduce the effect of complex vibrational reservoirs characteristic of organic molecules. Our findings reveal the key role played by the middle polariton as the nonlocal intermediary in the transmission of excitations from donor to acceptor molecules. We also provide analytical insights on the key physical magnitudes that help to optimize the efficiency of the long-range energy transferThis work has been funded by the European Research Council under Grant Agreements No. ERC-2011-AdG 290981 and No. ERC- 2016-STG-714870, the EU Seventh Framework Programme (FP7-PEOPLE-2013-CIG-630996 and FP7-PEOPLE-2013- CIG-618229), and the Spanish MINECO under Contracts No. MAT2014-53432-C5-5-R and No. FIS2015-64951-R, as well as through the “María de Maeztu” programme for Units of Excellence in R&D (MDM-2014-0377)

    Enhancing photon correlations through plasmonic strong coupling

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    © 2017 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibitedThere is an increasing scientific and technological interest in the design and implementation of nanoscale sources of quantum light. Here, we investigate the quantum statistics of the light scattered from a plasmonic nanocavity coupled to a mesoscopic ensemble of emitters under low coherent pumping. We present an analytical description of the intensity correlations taking place in these systems and unveil the fingerprint of plasmon-exciton-polaritons in them. Our findings reveal that plasmonic cavities are able to retain and enhance excitonic nonlinearities, even when the number of emitters is large. This makes plasmonic strong coupling a promising route for generating nonclassical light beyond the single-emitter levelFP7 Ideas: European Research Council (IDEASERC) (ERC-2011-AdG 290981, ERC-2016-STG-714870, FP7-PEOPLE-2013-CIG-618229, FP7-PEOPLE-2013-CIG630996); Ministerio de Economía y Competitividad (MINECO) (FIS2015-64951-R, MAT2014-53432-C5-5-R, MDM-2014-0377

    Modifications in the distribution of met-enkephalin in the cat spinal cord after administration of clonidine. An immunocytochemical study

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    We have studied the modifications in the distribution of methionine-enkephalin in the cat spinal cord after intravenous or intrathecal administration of clonidine by using an immunocytochemical technique. In animals not treated with the substance, a very high density of immunoreactive fibers was found in layers I and 11; a high density in the dorso-lateral funiculus and in the reticular formation; a moderate density in layers 111, IV and V; and a low density in layer VI. However, after intravenous or intrathecal administration of clonidine a decrease in fibers containing met-enkephalin was observed in layers I and I1 (high or moderate density), the dorso-lateral funiculus, and the reticular formation (moderate or low density), and in layers IV and V (low or very low density). In all cases, the decrease in the immunoreactivity was more marked when clonidine was administered intrathecally. Our results suggest that clonidine induces the release of metenkephalin in the spinal cord. They further suggest that the opioid peptide released could be involved in the control of nociceptive transmission by inhibiting the release of neurotransmitters (e.g., substance P). In summary, our study shows that clonidine could be involved in antinociceptive mechanisms in the cat spinal cord

    Quantum entanglement patterns in the structure of atomic nuclei within the nuclear shell model

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    Quantum entanglement offers a unique perspective into the underlying structure of strongly-correlated systems such as atomic nuclei. In this paper, we use quantum information tools to analyze the structure of light and medium mass berillyum, oxygen, neon and calcium isotopes within the nuclear shell model. We use different entanglement metrics, including single-orbital entanglement, mutual information, and von Neumann entropies for different equipartitions of the shell-model valence space and identify mode/entanglement patterns related to the energy, angular momentum and isospin of the nuclear single-particle orbitals. We observe that the single-orbital entanglement is directly related to the number of valence nucleons and the energy structure of the shell, while the mutual information highlights signatures of proton-proton and neutron-neutron pairing. Proton and neutron orbitals are weakly entangled by all measures, and in fact have the lowest von Neumann entropies among all possible equipartitions of the valence space. In contrast, orbitals with opposite angular momentum projection have relatively large entropies. This analysis provides a guide for designing more efficient quantum algorithms for the noisy intermediate-scale quantum era.Comment: Submitted to EPJA Topical Issue "Quantum computing in low-energy nuclear theory

    Painlev\'e-Gullstrand synchronizations in spherical symmetry

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    A Painlev\'e-Gullstrand synchronization is a slicing of the space-time by a family of flat spacelike 3-surfaces. For spherically symmetric space-times, we show that a Painlev\'e-Gullstrand synchronization only exists in the region where (dr)21(dr)^2 \leq 1, rr being the curvature radius of the isometry group orbits (22-spheres). This condition says that the Misner-Sharp gravitational energy of these 2-spheres is not negative and has an intrinsic meaning in terms of the norm of the mean extrinsic curvature vector. It also provides an algebraic inequality involving the Weyl curvature scalar and the Ricci eigenvalues. We prove that the energy and momentum densities associated with the Weinberg complex of a Painlev\'e-Gullstrand slice vanish in these curvature coordinates, and we give a new interpretation of these slices by using semi-metric Newtonian connections. It is also outlined that, by solving the vacuum Einstein's equations in a coordinate system adapted to a Painlev\'e-Gullstrand synchronization, the Schwarzschild solution is directly obtained in a whole coordinate domain that includes the horizon and both its interior and exterior regions.Comment: 16 page

    The Cotton tensor in Riemannian spacetimes

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    Recently, the study of three-dimensional spaces is becoming of great interest. In these dimensions the Cotton tensor is prominent as the substitute for the Weyl tensor. It is conformally invariant and its vanishing is equivalent to conformal flatness. However, the Cotton tensor arises in the context of the Bianchi identities and is present in any dimension. We present a systematic derivation of the Cotton tensor. We perform its irreducible decomposition and determine its number of independent components for the first time. Subsequently, we exhibit its characteristic properties and perform a classification of the Cotton tensor in three dimensions. We investigate some solutions of Einstein's field equations in three dimensions and of the topologically massive gravity model of Deser, Jackiw, and Templeton. For each class examples are given. Finally we investigate the relation between the Cotton tensor and the energy-momentum in Einstein's theory and derive a conformally flat perfect fluid solution of Einstein's field equations in three dimensions.Comment: 27 pages, revtex
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