Tunable and robust long-range coherent interactions between quantum emitters mediated by Weyl bound states

Long-range coherent interactions between quantum emitters are instrumental for quantum information and simulation technologies, but they are generally difficult to isolate from dissipation. Here, we show how such interactions can be obtained in photonic Weyl environments due to the emergence of an exotic bound state whose wavefunction displays power-law spatial confinement. Using an exact formalism, we show how this bound state can mediate coherent transfer of excitations between emitters, with virtually no dissipation and with a transfer rate that follows the same scaling with distance as the bound state wavefunction. In addition, we show that the topological nature of Weyl points translates into two important features of the Weyl bound state, and consequently of the interactions it mediates: first, its range can be tuned without losing the power-law confinement, and, second, they are robust under energy disorder of the bath. To our knowledge, this is the first proposal of a photonic setup that combines simultaneously coherence, tunability, long-range, and robustness to disorder. These findings could ultimately pave the way for the design of more robust long-distance entanglement protocols or quantum simulation implementations for studying long-range interacting systems

Wavelength de-multiplexing properties of a single aperture flanked by periodic arrays of indentations

In this paper we explore the transmission properties of single subwavelength apertures perforated in thin metallic films flanked by asymmetric configurations of periodic arrays of indentations. It is shown how the corrugation in the input side can be used to transmit selectively only two different wavelengths. Also, by tuning the geometrical parameters defining the corrugation of the output side, these two chosen wavelengths can emerge from the structure as two very narrow beams propagating at well-defined directions. This new ability of structured metals can be used as a base to build micron-sized wavelength de-multiplexers.Comment: Accepted for publication in Photonics and Nanostructure

El consejo de administración y la reputación corporativa: un análisis empírico

Purpose – The purpose of this paper is to test the association between board of director characteristics and corporate reputation. Design/methodology/approach – Logistic and multivariate regressions are performed to analyse whether the board of director characteristics are associated with the level of corporate reputation. The sample is composed of listed companies in the Madrid Stock Exchange (Índice General de la Bolsa de Madrid)atleastonceduringtheperiod2004-2010.Corporategovernancedataweremanuallyextracted from governance reports released by Spanish companies. The data for the design of a corporate reputation measure were obtained from the Monitor Español de Reputación Corporativa (MERCO) institute web site. Findings – Results from the empirical analysis show that Spanish companies that appear high up in terms of ranking in the reputation index provided by MERCO tend to have a higher percentage of independent directors as well as more female directors on their board. Firm size and the image of the president of a firm are also linked to corporate reputation. Originality/value – The results have direct implications for the management of corporate governance mechanisms by shareholders who should take into account their role in the creation and maintenance of corporate reputation.Objetivo El objetivo de este trabajo es analizar la asociación entre las características de los consejos de administración y la reputación corporativa. Metodología La metodología empleada se basa en el uso de regresiones logísticas y multivariantes. Nuestra muestra se compone de las empresas que cotizaron en el Índice General de la Bolsa de Madrid (IGBM) durante el período 2004-2010. Los datos sobre gobierno corporativo se obtuvieron manualmente a partir de los informes de gobierno corporativo publicados por las empresas españolas. La información para diseñar la medida de la reputación corporativa se obtuvo de la página web de MERCO (Monitor Español de Reputación Corporativa). Resultados Los resultados del análisis empírico muestran que las empresas españolas que aparecen en las posiciones más altas del ranking de reputación corporativa proporcionado por MERCO tienden a tener un mayor porcentaje de directores independientes y de mujeres en sus consejos de administración. El tamaño de la empresa y la reputación del presidente también están relacionados con la reputación corporativa. Originalidad Los resultados tienen implicaciones directas para la gestión de los mecanismos de gobierno corporativo por parte de los accionistas, que deberían considerar el papel de los consejos de administración en la creación y mantenimiento de la reputación corporativa

Theory of extraordinary transmission of light through quasiperiodic arrays of subwavelength holes

By using a theoretical formalism able to work in both real and k-spaces, the physical origin of the phenomenon of extraordinary transmission of light through quasi-periodic arrays of holes is revealed. Long-range order present in a quasiperiodic array selects the wavevector(s) of the surface electromagnetic mode(s) that allows an efficient transmission of light through subwavelength holes.Comment: 4 pages, 4 figure