489 research outputs found
Is the pseudogap a topological state?
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 SR experiments.Comment: 12 pages, six figures, one tabl
Topologically stable gapped state in a layered superconductor
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 SR 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
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
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
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
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
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