489 research outputs found

    Is the pseudogap a topological state?

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    We conjecture that the pseudogap is an inhomogeneous condensate above the homogeneous state whose existence is granted by topological stability. We consider the simplest possible order parameter theory that provides this interpretation of the pseudogap and study its angular momentum states. The normal state gap density, the breaking of the time reversal symmetry and the checkerboard pattern are naturally explained under this view. The pseudogap is a lattice of skyrmions and the inner weak local magnetic field falls below the experimental threshold of observation given by NMR/NQR and μ\muSR experiments.Comment: 12 pages, six figures, one tabl

    Topologically stable gapped state in a layered superconductor

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    We show that a layered superconductor, described by a two-component order parameter, has a gapped state above the ground state, topologically protected from decay, containing flow and counter flow in the absence of an applied magnetic field. This state is made of skyrmions, breaks time reversal symmetry and produces a weak local magnetic field below the present threshold of detection by μ\muSR and NMR/NQR. We estimate the density of carriers that condense into the pseudogap.Comment: 6 pages, 4 figure

    Planeamiento estratégico para la provincia de Ascope

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    El presente Planeamiento Estratégico para la provincia de Ascope se elaboró con la finalidad de descentralizar el crecimiento de la región, propiciar un avance económico y garantizar un crecimiento sostenible en el tiempo. Este planeamiento estratégico articula todas las ventajas competitivas de la provincia, priorizando el bienestar de la población. Por las bondades de su clima y suelo fértil, la provincia cuenta con atractivos naturales y es propicio no sólo para la agricultura y turismo, sino también para desarrollar aquellas industrias de desarrollo sustentables con el medio ambiente. Es así que al analizar las fortalezas y debilidades de la provincia se proponen el desarrollo de tres pilares: agroindustria, energías renovables y el turismo. Cabe resaltar que en este proceso se profundiza la participación ciudadana y del gobierno, luchando así contra la pobreza e incentivando la inclusión social, esto con el fin de convertir a la provincia de Ascope en una región con un ambiente seguro para vivir, trabajar y visitarThe present Strategic Planning for the province of Ascope was developed with the purpose of decentralizing the growth of the region, propitiate an economic advance and guarantee a sustainable way. This strategic planning articulates all the competitive advantages of the province, prioritizing the welfare of the population. Due to the benefits of its climate and fertile soil, the province has natural attractions and is conducive not only for agriculture and tourism, but also to develop those sustainable development industries with the environment. Thus, when analyzing the strengths and weaknesses of the province, we proposed the development of three pillars is proposed: agroindustry, renewable energies and geriatric tourism. It is worth noting that this process deepens the participation of citizens and the government, thus fighting against poverty and encouraging social inclusion, this with the aim of to convert the Ascope province in a region with a safe environment to live, work and visitTesi

    The Principle Of Local Rotational Invariance And The Coexistence Of Magnetism, Charge And Superconductivity

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    We propose a macroscopic description of the superconducting state in presence of an applied external magnetic field in terms of first order differential equations. They describe a corrugated two-component order parameter intertwined with a spin-charged background, caused by spin correlations and charged dislocations. The first order differential equations are a consequence of a Weitzenb\"ock-Liechnorowitz identity which renders a SUL(2) \otimes UL(1) invariant ground state, based on (L) local rotational and electromagnetic gauge symmetry. The proposal is based on a long ago developed formalism by \'Elie Cartan to investigate curved spaces, viewed as a collection of small Euclidean granules that are translated and rotated with respect to each other. \'Elie Cartan's formalism unveils the principle of local rotational invariance as a gauge symmetry because the global SU(2) invariance of the order parameter is turned local by the interlacement of spin and charge to pairing.Comment: 19 pages, 3 figure

    Shape-resonant superconductivity in nanofilms: from weak to strong coupling

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    Ultrathin superconductors of different materials are becoming a powerful platform to find mechanisms for enhancement of superconductivity, exploiting shape resonances in different superconducting properties. Here we evaluate the superconducting gap and its spatial profile, the multiple gap components, and the chemical potential, of generic superconducting nanofilms, considering the pairing attraction and its energy scale as tunable parameters, from weak to strong coupling, at fixed electron density. Superconducting properties are evaluated at mean field level as a function of the thickness of the nanofilm, in order to characterize the shape resonances in the superconducting gap. We find that the most pronounced shape resonances are generated for weakly coupled superconductors, while approaching the strong coupling regime the shape resonances are rounded by a mixing of the subbands due to the large energy gaps extending over large energy scales. Finally, we find that the spatial profile, transverse to the nanofilm, of the superconducting gap acquires a flat behavior in the shape resonance region, indicating that a robust and uniform multigap superconducting state can arise at resonance.Comment: 7 pages, 4 figures. Submitted to the Proceedings of the Superstripes 2016 conferenc

    Local hydrological conditions influence tree diversity and composition across the Amazon basin

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    Tree diversity and composition in Amazonia are known to be strongly determined by the water supplied by precipitation. Nevertheless, within the same climatic regime, water availability is modulated by local topography and soil characteristics (hereafter referred to as local hydrological conditions), varying from saturated and poorly drained to well-drained and potentially dry areas. While these conditions may be expected to influence species distribution, the impacts of local hydrological conditions on tree diversity and composition remain poorly understood at the whole Amazon basin scale. Using a dataset of 443 1-ha non-flooded forest plots distributed across the basin, we investigate how local hydrological conditions influence 1) tree alpha diversity, 2) the community-weighted wood density mean (CWM-wd) – a proxy for hydraulic resistance and 3) tree species composition. We find that the effect of local hydrological conditions on tree diversity depends on climate, being more evident in wetter forests, where diversity increases towards locations with well-drained soils. CWM-wd increased towards better drained soils in Southern and Western Amazonia. Tree species composition changed along local soil hydrological gradients in Central-Eastern, Western and Southern Amazonia, and those changes were correlated with changes in the mean wood density of plots. Our results suggest that local hydrological gradients filter species, influencing the diversity and composition of Amazonian forests. Overall, this study shows that the effect of local hydrological conditions is pervasive, extending over wide Amazonian regions, and reinforces the importance of accounting for local topography and hydrology to better understand the likely response and resilience of forests to increased frequency of extreme climate events and rising temperatures

    Estimating the global conservation status of more than 15,000 Amazonian tree species

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