Propagation of spatially entangled qudits through free space

We show the propagation of entangled states of high-dimensional quantum systems. The qudits states were generated using the transverse correlation of the twin photons produced by spontaneous parametric down-conversion. Their free-space distribution was performed at the laboratory scale and the propagated states maintained a high-fidelity with their original form. The use of entangled qudits allow an increase in the quantity of information that can be transmitted and may also guarantee more privacy for communicating parties. Therefore, studies about propagating entangled states of qudits are important for the effort of building quantum communication networks.Comment: 5 Pages, 4 Figures, REVTeX

Differences in coastal and oceanic SST trends north of Yucatan Peninsula

The coastal area north of Yucatan has experienced a cooling SST trend from 1982 to 2015 during the upwelling season (May–September) that contrasts with the warming observed at the adjacent ocean area. Different drivers were analyzed to identify the possible causes of that unusual coastal cooling. Changes in coastal upwelling and in sea-atmosphere heat fluxes are not consistent with the observed coastal cooling. The eastward shift of the Yucatan Current observed over the last decades is hypothesized as the most probable cause of coastal cooling. This shift enhances the vertical transport of cold deeper water to the continental shelf from where it is pumped to the surface by upwelling favorable westerly winds.publishe

Plasmons in layered structures including graphene

We investigate the optical properties of layered structures with graphene at the interface for arbitrary linear polarization at finite temperature including full retardation by working in the Weyl gauge. As a special case, we obtain the full response and the related dielectric function of a layered structure with two interfaces. We apply our results to discuss the longitudinal plasmon spectrum of several single and double layer devices such as systems with finite and zero electronic densities. We further show that a nonhomogeneous dielectric background can shift the relative weight of the in-phase and out-of-phase mode and discuss how the plasmonic mode of the upper layer can be tuned into an acoustic mode with specific sound velocity.Comment: 18 pages, 6 figure

Graphene plasmons and retardation: strong light-matter coupling

We study the retardation regime of doped graphene plasmons, given by the nominal crossing of the unretarded plasmon and light-cone. In addition to modifications in the plasmon dispersion relation, retardation implies strong coupling between propagating light and matter, even for homogeneous graphene, which opens up the possibility of efficient plasmonics in simple graphene devices. We exemplify this enhancement in a double-layer configuration that exhibits {\em perfect} (if lossless) light transmissions across a classically forbidden region, providing a simpler analog of the corresponding phenomenon in perforated metal sheets. We also show that (broad) Fabry-P\'erot resonances present without graphene turn into sharply peaked, quasi-discrete modes in the presence of graphene where graphene's response function is given by the typical Fano lineshape.Comment: 6 pages, 4 figure

A data science approach for spatiotemporal modelling of low and resident air pollution in Madrid (Spain): Implications for epidemiological studies

Model developments to assess different air pollution exposures within cities are still a key challenge in environmental epidemiology. Background air pollution is a long-term resident and low-level concentration pollution difficult to quantify, and to which population is chronically exposed. In this study, hourly time series of four key air pollutants were analysed using Hidden Markov Models to estimate the exposure to background pollution in Madrid, from 2001 to 2017. Using these estimates, its spatial distribution was later analysed after combining the interpolation results of ordinary kriging and inverse distance weighting. The ratio of ambient to background pollution differs according to the pollutant studied but is estimated to be on average about six to one. This methodology is proposed not only to describe the temporal and spatial variability of this complex exposure, but also to be used as input in new modelling approaches of air pollution in urban areas. (c) 2018 The Author

Super-poissonian photon statistics and correlations between pump and probe fields in Electromagnetically Induced Transparency

We have measured the photon statistics of pump and probe beams after interaction with Rb atoms in a situation of Electromagnetically Induced Transparency. Both fields present super-poissonian statistics and their intensities become correlated, in good qualitative agreement with theoretical predictions in which both fields are treated quantum-mechanically. The intensity correlations measured are a first step towards the observation of entanglement between the fields.Comment: 4 pages, two-column, 4 figures, first submitted to PRL on Aug. 6, 200

Relación entre consumo de alcohol y autoestima en adolescentes

[Resumen] Numerosas investigaciones sobre las conductas de salud en los adolescentes, han intentado determinar los principales factores, tanto demográficos como psicosocia1es, implicados en el inicio y mantenimiento del consumo de alcohol. Aunque uno de los factores más estudiados ha sido la autoestima, los resultados sobre su relación con el alcohol no son claros. En el presente estudio se analiza la relación entre el consumo de alcohol y los niveles de autoestima en una muestra de 415 adolescentes, de edades comprendidas entre los 12 y los 18 años, que cursan entre 10 y 40 de la E.S.O. Además de analizar los niveles medios de autoestima, se ha dividido la muestra por subgrupos de sujetos con autoestima muy baja y autoestima muy alta, y se ha intentando determinar su relación con el consumo de alcohol, por sexos y cursos. Los resultados de los análisis no avalan la hipótesis de la existencia de una relación entre los niveles de autoestima y el consumo de alcohol en la presente muestra de adolescente

Relación entre consumo de alcohol y eutoestima en adolescentes

[Resumen] Numerosas investigaciones sobre las conductas de salud en los adolescentes, han intentado determinar los principales factores, tanto demográficos como psicosocia1es, implicados en el inicio y mantenimiento del consumo de alcohol. Aunque uno de los factores más estudiados ha sido la autoestima, los resultados sobre su relación con el alcohol no son claros. En el presente estudio se analiza la relación entre el consumo de alcohol y los niveles de autoestima en una muestra de 415 adolescentes, de edades comprendidas entre los 12 y los 18 años, que cursan entre 10 y 40 de la E.S.O. Además de analizar los niveles medios de autoestima, se ha dividido la muestra por subgrupos de sujetos con autoestima muy baja y autoestima muy alta, y se ha intentando determinar su relación con el consumo de alcohol, por sexos y cursos. Los resultados de los análisis no avalan la hipótesis de la existencia de una relación entre los niveles de autoestima y el consumo de alcohol en la presente muestra de adolescentes