Minimum Noise Optical Coatings for Interferometric Detectors of Gravitational Waves

Coating Brownian noise is the dominant noise term, in a frequency band from a few tens to a few hundreds Hz, for all Earth-bound detectors of gravitational waves. Minimizing such noise is mandatory to increase the visibility distance of these instruments, and eventually reach their quantum limit. Several strategies are possible to achieve this goal. Layer thickness optimization is the simplest option, yielding a sensible noise reduction with limited technological challenges. Experimental results confirm the accuracy of the underlying theory, and the robustness of the design.Comment: 6 pages, 9 figures, 50 references, Proc of the IEEE International Workshop on Metrology for Aerospace 201

Robust Gravitational Wave Burst Detection and Source Localization in a Network of Interferometers Using Cross Wigner Spectra

We discuss a fast cross-Wigner transform based technique for detecting gravitational wave bursts, and estimating the direction of arrival, using a network of (three) non co-located interferometric detectors. The performances of the detector as a function of signal strength and source location, and the accuracy of the direction of arrival estimation are investigated by numerical simulations.Comment: accepted in Class. Quantum Gravit

Modeling the Impulsive Noise Component and its Effect on the Operation of a Simple Coherent Network Algorithm for Unmodeled Gravitational Wave Bursts Detection

An analytic model a la Middleton of the impulsive noise component in the data of interferometric gravitational wave detectors is proposed, based on an atomic representation of glitches. A fully analytic characterization of the coherent network data analysis algorithm proposed by Rakhmanov and Klimenko is obtained, for the simplest relevant case of triggered detection of unmodeled gravitational wave bursts, using the above noise model. The detector's performance is evaluated under a suitable central-limit hypothesis, and the effects of both the noisiness of the pseudo-templates, and the presence of the impulsive noise component are highlighted.Comment: 15 pages, 8 figure

Enhanced Photoluminescence with Dielectric Nanostructures: A review

Abstract Resonant dielectric subwavelength structures made of high-refractive-index materials are an emerging powerful platform with unique advantages compared to plasmonic based nanostructures. Owing to the low ohmic losses, to their ability to localize optical near-field at nanoscale, and exciting both electric and magnetic resonant modes, high-index dielectric materials are being used in various applications. Starting from the first principles, we aim at showing how resonant dielectric nanostructures can be efficiently used to enhance photoluminescence signal from an excited molecule, and we review the most recent results present in the Literature

Coaching educativo y compromiso laboral docente en una institución educativa particular de los Olivos, Lima, 2022

El estudio presentó como objetivo general establecer la relación entre el coaching educativo y el compromiso laboral de los docentes en una Institución Educativa Particular de los Olivos, Lima, 2022. Se trato de una investigación básica, con un diseño no experimental, enfoque cuantitativo y nivel correlacional. En cuanto a la población estuvo integrado por 50 docentes de una Institución Educativa Particular de los Olivos, siendo la muestra igual que la población, por lo que se utilizó el muestreo no probabilístico. Para el recojo de datos se aplicó la encuesta y como instrumento el cuestionario para medir ambas variables, siendo validados por los jurados expertos en materia, asimismo arrojo una confiabilidad usando el coeficiente de Alfa de Cronbach. Según los resultados señalaron que la variable coaching educativo se sostuvo en un nivel bueno según el 60%, mientras que el compromiso laboral también se ubicó en un nivel bueno según el 70%. Concluyendo que existe relación positiva y perfecta entre el coaching educativo y el compromiso laboral de los docentes en una Institución Educativa Particular de los Olivos, Lima, 2022, según (r= 0,908) y sig (p<0,05)

Gestión de seguridad ciudadana y la calidad de servicio en la municipalidad del distrito de San Borja, Lima, 2023

Esta investigación tuvo por objetivo determinar como la gestión de seguridad ciudadana se relaciona con la calidad de servicio en la municipalidad de San Borja, Lima, 2023. Se desarrolló bajo el enfoque cuantitativo, con diseño no experimental, nivel correlacional, de corte transversal. La población estuvo integrada por 600 miembros del área de seguridad ciudadana, con una muestra representativa de 234 encuestados, se recopilaron los datos mediante la técnica de la encuesta y el instrumento cuestionario, conformado por 15 ítems para cada variable, que previamente pasaron la prueba de fiabilidad usando el coeficiente Alfa de Cronbach, obteniendo un valor (α = 0.682) para la variable gestión de seguridad ciudadana y un valor (α = 0.808) para la variable calidad de servicio. Con respecto al análisis estadístico de los datos para verificar la hipótesis general, se obtuvo un coeficiente Rho de Spearman (Rho = 0.562) y significancia bilateral (p = 0.000 < 0,05) el cual indica una correlación positiva moderada entre las variables, lo que nos lleva a la conclusión de que los esfuerzos realizados en estrategias de gestión ciudadana permiten elevar el nivel de calidad de servicio ofrecido a los ciudadanos

Measurement of Thermal Noise in Multilayer Coatings with Optimized Layer Thickness

A standard quarter-wavelength multilayer optical coating will produce the highest reflectivity for a given number of coating layers, but in general it will not yield the lowest thermal noise for a prescribed reflectivity. Coatings with the layer thicknesses optimized to minimize thermal noise could be useful in future generation interferometric gravitational wave detectors where coating thermal noise is expected to limit the sensitivity of the instrument. We present the results of direct measurements of the thermal noise of a standard quarter-wavelength coating and a low noise optimized coating. The measurements indicate a reduction in thermal noise in line with modeling predictions.Comment: 8 pages, 14 figure

Material loss angles from direct measurements of broadband thermal noise

International audienceWe estimate the loss angles of the materials currently used in the highly reflective test-mass coatings of interferometric detectors of gravitational waves, namely Silica, Tantala, and Ti-doped Tantala, from direct measurement of coating thermal noise in an optical interferometer testbench, the Caltech TNI. We also present a simple predictive theory for the material properties of amorphous glassy oxide mixtures, which gives results in good agreement with our measurements on Ti-doped Tantala. Alternative measurement methods and results are reviewed, and some critical issues are discussed

The role of Physicists in the «rebirth of a scientific movement» in Portugal during the inter war period

The advent of Republic in 1910 brought important higher education reforms in Portugal. In spite of strong political and financial difficulties in the next two decades, Portuguese universities supported graduation studies of young physics teachers abroad. However these relevant initiatives Portuguese republican government was not successful in creating a national institution able to promote and funding the organization of scientific research. Only in 1929 the government was able to set up this kind of institution, the “National Board of Education” [Junta de Educação Nacional], with the aim of funding research centres in the universities, as well as of providing grants for students to continue their studies at advanced level both at home and abroad. In the thirties an important group of young researchers went on to study in universities and laboratories of European advanced scientific countries, where some of them got their PhD degree. In Chemistry, Mathematics and Physics the school more demanded was Paris University. During this period Curie’s laboratory received an important group of Portuguese students. After four years stay abroad, having established important international scientific links, back at home, some of these young scientists played an important role in their universities promoting a rebirth of a scientific movement. This lasted till the end of the Second World War, when a good number of them were dismissed from their positions because of their active opposition to Salazar’s regime. Arriving home having experienced living in cities with intense political activity, some of these young scientists demonstrated a strong political commitment against the dictatorship regime and supported important activity in scientific associations and cultural organizations. The study of the scientific, cultural and political activity of this group is the purpose of this communication