13,914 research outputs found

    Classical Emergence of Intrinsic Spin-Orbit Interaction of Light at the Nanoscale

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    Traditionally, in macroscopic geometrical optics intrinsic polarization and spatial degrees of freedom of light can be treated independently. However, at the subwavelength scale these properties appear to be coupled together, giving rise to the spin-orbit interaction (SOI) of light. In this work we address theoretically the classical emergence of the optical SOI at the nanoscale. By means of a full-vector analysis involving spherical vector waves we show that the spin-orbit factorizability condition, accounting the mutual influence between the amplitude (spin) and phase (orbit), is fulfilled only in the far-field limit. On the other side, in the near-field region, an additional relative phase introduces an extra term that hinders the factorization and reveals an intricate dynamical behavior according to the SOI regime. As a result, we find a suitable theoretical framework able to capture analytically the main features of intrinsic SOI of light. Besides allowing for a better understanding into the mechanism leading to its classical emergence at the nanoscale, our approach may be useful in order to design experimental setups that enhance the response of SOI-based effects.Comment: 10 pages, 5 figure

    A cross-country quarterly database of real house prices: a methodological note

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    We build from (mainly) publicly available national sources a database of (nominal and real) house prices—complemented with data on private disposable income (PDI)—for 19 advanced countries at a quarterly frequency, starting in the first quarter of 1975. We select a house price index for each country that is consistent with the U.S. FHFA quarterly nationwide house price index for existing single-family houses (formerly called OFHEO house price index), and extend the country series back to 1975 with available historical data whenever necessary. Each house price index is seasonallyadjusted over the entire sample period and then rebased to 2005 = 100.> ; The house price indexes are expressed in nominal terms, and also in real terms using the personal consumption expenditure (PCE) deflator of the corresponding country. PDIs are always quoted in per capita terms using working age population of the corresponding country and can be similarly expressed in real terms with the PCE deflator. We aggregate all 19 countries in our database, weighted by their purchasing power parity-adjusted GDP shares in 2005, to compute an average (nominal and real) house price series and an average (nominal and real) per capita PDI series.Macroeconomics - Econometric models ; Income ; Gross domestic product

    A historical look at the labor market during recessions

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    Turmoil in housing, credit and financial markets plunged the U.S. economy into a recession that has taken a heavy toll on the labor market. The weakness that began during the second half of 2007 gravely worsened during a period of extreme financial stress in 2008, and the labor market has yet to recover. To put the recession's labor-market impact into perspective, we compare the past two years to previous downturns, including the Great Depression. We also examine the data commonly used to assess labor market conditions. While unemployment rates and nonfarm payroll losses are widely reported, a firm grasp of what they measure is critical to understanding what they tell us about the current state of the labor market.Recessions ; Labor market ; Unemployment

    Increased real house price volatility signals break from Great Moderation

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    The shift toward more volatile real house price growth, unaccompanied by a shift in the volatility of real GDP growth, offers evidence that house price dynamics and real output growth may have diverged beginning around the 2001 recession.Gross domestic product

    Multiscale computational homogenization: review and proposal of a new enhanced-first-order method

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    This is a copy of the author 's final draft version of an article published in the Archives of computational methods in engineering. The final publication is available at Springer via http://dx.doi.org/10.1007/s11831-016-9205-0The continuous increase of computational capacity has encouraged the extensive use of multiscale techniques to simulate the material behaviour on several fields of knowledge. In solid mechanics, the multiscale approaches which consider the macro-scale deformation gradient to obtain the homogenized material behaviour from the micro-scale are called first-order computational homogenization. Following this idea, the second-order FE2 methods incorporate high-order gradients to improve the simulation accuracy. However, to capture the full advantages of these high-order framework the classical boundary value problem (BVP) at the macro-scale must be upgraded to high-order level, which complicates their numerical solution. With the purpose of obtaining the best of both methods i.e. first-order and second-order, in this work an enhanced-first-order computational homogenization is presented. The proposed approach preserves a classical BVP at the macro-scale level but taking into account the high-order gradient of the macro-scale in the micro-scale solution. The developed numerical examples show how the proposed method obtains the expected stress distribution at the micro-scale for states of structural bending loads. Nevertheless, the macro-scale results achieved are the same than the ones obtained with a first-order framework because both approaches share the same macro-scale BVP.Peer ReviewedPostprint (author's final draft

    The consequences of nihilism

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    Este estudio pretende aportar una imagen de lo que supone el nihilismo de Nietzsche y Heidegger a los ojos de un pensador como Gianni Vattimo. Para empezar se relatará de manera breve cuál es la concepción de ambos, en concreto que presta atención al concepto de la Verwindung. Las consecuencias que tal doctrina, apoyada siempre en el eterno retorno y la voluntad de poder, son las siguientes: la disolución del sujeto, la hermenéutica nihilista y el pensamiento débil. Todo ello se resume en la posmodernidad filosófica. El interés se reduce, por lo tanto, a intentar entender la época actual.This paper seeks to provide an image of what are the results of the nihilism inaugurated by Nietzsche and Heidegger and it is seen through Vattimo’s eyes. First of all, we are going to expose shortly the conception of both of them, in particular the German concept of Verwindung. The consequences of this doctrine, always based on the eternal return and the Will to power, are the following ones: subject’s dissolution, the nihilistic hermeneutics and the weak think. It can be summarized in the philosophical postmodernity. So, the interest here is reduced in an attempt to understand the present time

    On the Structure of Higher Order Voronoi Cells

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    The classic Voronoi cells can be generalized to a higher-order version by considering the cells of points for which a given kk-element subset of the set of sites consists of the kk closest sites. We study the structure of the kk-order Voronoi cells and illustrate our theoretical findings with a case study of two-dimensional higher-order Voronoi cells for four points.Comment: Minor correction
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