746 research outputs found
High intrinsic energy resolution photon number resolving detectors
Transition Edge Sensors (TESs) are characterized by the intrinsic figure of
merit to resolve both the energy and the statistical distribution of the
incident photons. These properties lead TES devices to become the best single
photon detector for quantum technology experiments. For a TES based on titanium
and gold has been reached, at telecommunication wavelength, an unprecedented
intrinsic energy resolution (0.113 eV). The uncertainties analysis of both
energy resolution and photon state assignment has been discussed. The thermal
properties of the superconductive device have been studied by fitting the bias
curve to evaluate theoretical limit of the energy resolution
E-beam evaporated ZnO thin films: Fabrication and characterization as UV detector
partially_open5In the present paper, fabrication and structural, optical and electrical characterization of ZnO thin films grown by electron gun technique are reported and the performances of a prototype of UV photodetector based on them are illustrated. ZnO thin films, fabricated on sapphire by e-beam evaporation followed by a two-step ex situ treatment (annealing and oxidation), are polycrystalline, with a smooth surface and show very good visible transparency and an energy gap of 3.2 eV. Preliminary results on fabrication and characterization of an UV detector are reported. The Al interdigitated contacts show a Schottky behavior, which is strongly desired in view of applications since it has many advantages in the aspects of high quantum efficiency, response time, low dark current, high UV/visible contrast and possible zero-bias operation.partially_openPortesi C; Lolli L; Taralli E; Rajteri M; Monticone EPortesi, Chiara; Lolli, L; Taralli, Emanuele; Rajteri, Mauro; Monticone, Eugeni
Order Picking Systems: A Queue Model for Dimensioning the Storage Capacity, the Crew of Pickers, and the AGV Fleet
Designing an order picking system can be very complex, as several interrelated control variables are involved. We address the sizing of the storage capacity of the picking bay, the crew of pickers, and the AGV fleet, which are the most important variables from a tactical viewpoint in a parts-to-pickers system. Although order picking is a widely explored topic in the literature, no analytical model that can simultaneously deal with these variables is currently available. To bridge this gap, we introduce a queue model for Markovian processes, which enables us to jointly optimise the aforementioned control variables. A discrete-event simulation is then used to validate our model, and we then test our proposal with real data under different operative scenarios, with the aim of assessing the usefulness of the proposal in real settings
Quantifying the Direct Radiative Effect of Absorbing Aerosols for Numerical Weather Prediction: A Case Study
We conceptualize aerosol radiative transfer processes arising from the hypothetical coupling of a global aerosol transport model and a global numerical weather prediction model by applying the US Naval Research Laboratory Navy Aerosol Analysis and Prediction System (NAAPS) and the Navy Global Environmental Model (NAVGEM) meteorological and surface reflectance fields. A unique experimental design during the 2013 NASA Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) field mission allowed for collocated airborne sampling by the high spectral resolution Lidar (HSRL), the Airborne Multi-angle SpectroPolarimetric Imager (AirMSPI), up/down shortwave (SW) and infrared (IR) broadband radiometers, as well as NASA A-Train support from the Moderate Resolution Imaging Spectroradiometer (MODIS), to attempt direct aerosol forcing closure. The results demonstrate the sensitivity of modeled fields to aerosol radiative fluxes and heating rates, specifically in the SW, as induced in this event from transported smoke and regional urban aerosols. Limitations are identified with respect to aerosol attribution, vertical distribution, and the choice of optical and surface polarimetric properties, which are discussed within the context of their influence on numerical weather prediction output that is particularly important as the community propels forward towards inline aerosol modeling within global forecast systems
Self consistent, absolute calibration technique for photon number resolving detectors
Well characterized photon number resolving detectors are a requirement for
many applications ranging from quantum information and quantum metrology to the
foundations of quantum mechanics. This prompts the necessity for reliable
calibration techniques at the single photon level. In this paper we propose an
innovative absolute calibration technique for photon number resolving
detectors, using a pulsed heralded photon source based on parametric down
conversion. The technique, being absolute, does not require reference standards
and is independent upon the performances of the heralding detector. The method
provides the results of quantum efficiency for the heralded detector as a
function of detected photon numbers. Furthermore, we prove its validity by
performing the calibration of a Transition Edge Sensor based detector, a real
photon number resolving detector that has recently demonstrated its
effectiveness in various quantum information protocols.Comment: 9 pages, 2 figure
The Wonder of Colors and the Principle of Ariadne
The Principle of Ariadne, formulated in 1988 ago by Walter Carnielli
and Carlos Di Prisco and later published in 1993, is an infinitary principle that is independent of the Axiom of Choice in ZF, although it can be consistently added to
the remaining ZF axioms. The present paper surveys, and motivates, the foundational importance of the Principle of Ariadne
and proposes the Ariadne Game, showing that the Principle of Ariadne,
corresponds precisely
to a winning strategy for the Ariadne Game. Some relations to other
alternative. set-theoretical principles
are also briefly discussed
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