5,281 research outputs found
Constraints on the cosmic ray diffusion coefficient in the W28 region from gamma-ray observations
GeV and TeV gamma rays have been detected from the supernova remnant W28 and
its surroundings. Such emission correlates quite well with the position of
dense and massive molecular clouds and thus it is often interpreted as the
result of hadronic cosmic ray interactions in the dense gas. Constraints on the
cosmic ray diffusion coefficient in the region can be obtained, under the
assumption that the cosmic rays responsible for the gamma ray emission have
been accelerated in the past at the supernova remnant shock, and subsequently
escaped in the surrounding medium. In this scenario, gamma ray observations can
be explained only if the diffusion coefficient in the region surrounding the
supernova remnant is significantly suppressed with respect to the average
galactic one.Comment: To appear in the proceedings of "Journ\'ees de la SF2A 2010"
Marseille 21-24 June 2010, 4 pages, 4 figure
Quality Assurance Indicators of Long-Term Care in European Countries
This study reports on the quality indicators that were collected by the ANCIEN project partners in each country
considered in Work Package 5 (Quality in Long-Term Care). The main contribution of this report is a classification of
the quality assurance indicators in different European countries according to three dimensions: organisation type
(indicators applied to formal institutional care \u2013 FIC, formal home-based care \u2013 FHBC, formal home nursing care -
FHNC, and informal home care - IHC); quality dimensions (indicators about effectiveness, safety, patient value
responsiveness, or coordination) and system dimensions (input, process, or outcome indicators). The countries that
provided quality indicators, which are used at a national level or are recommended to be used at a local level by a
national authority, are: Estonia, Finland, France, Germany, Hungary, Italy, Latvia, the Netherlands, Spain, Sweden and
the United Kingdom. In total, we collected 390 quality indicators. Each quality indicator has been assigned to one or
more options in each dimension
Deep Strong Coupling Regime of the Jaynes-Cummings model
We study the quantum dynamics of a two-level system interacting with a
quantized harmonic oscillator in the deep strong coupling regime (DSC) of the
Jaynes-Cummings model, that is, when the coupling strength g is comparable or
larger than the oscillator frequency w (g/w > 1). In this case, the
rotating-wave approximation cannot be applied or treated perturbatively in
general. We propose an intuitive and predictive physical frame to describe the
DSC regime where photon number wavepackets bounce back and forth along parity
chains of the Hilbert space, while producing collapse and revivals of the
initial population. We exemplify our physical frame with numerical and
analytical considerations in the qubit population, photon statistics, and
Wigner phase space.Comment: Published version, note change of title: DSC regime of the JC mode
Zeno physics in ultrastrong circuit QED
We study the Zeno and anti-Zeno effects in a superconducting qubit
interacting strongly and ultrastrongly with a microwave resonator. Using a
model of a frequently measured two-level system interacting with a quantized
mode, we show different behaviors and total control of the Zeno times depending
on whether the rotating-wave approximation can be applied in the
Jaynes-Cummings model, or not. We exemplify showing the strong dependence of
our results with the properties of the initial field states and suggest
applications for quantum tomography.Comment: 5 pages, 3 figure
Digital Quantum Simulation of the Holstein Model in Trapped Ions
We propose the implementation of the Holstein model by means of digital
methods in a linear chain of trapped ions. We show how the simulation fidelity
scales with the generation of phononic excitations. We propose a decomposition
and a stepwise trapped-ion implementation of the Holstein Hamiltonian. Via
numerical simulations, we study how the protocol is affected by realistic
gates. Finally, we show how measurements of the size of the simulated polaron
can be performed.Comment: 5 pages + supplemental material, 3+3 figures. Accepted in Physical
Review Letter
Measuring Entanglement in a Photonic Embedding Quantum Simulator
Measuring entanglement is a demanding task that usually requires full
tomography of a quantum system, involving a number of observables that grows
exponentially with the number of parties. Recently, it was suggested that
adding a single ancillary qubit would allow for the efficient measurement of
concurrence, and indeed any entanglement monotone associated to antilinear
operations. Here, we report on the experimental implementation of such a
device---an embedding quantum simulator---in photonics, encoding the entangling
dynamics of a bipartite system into a tripartite one. We show that bipartite
concurrence can be efficiently extracted from the measurement of merely two
observables, instead of fifteen, without full tomographic information.Comment: Updated versio
HfO2 based memory devices with rectifying capabilities
We report on the fabrication and characterization of metal/insulator/metal capacitor like devices, with both rectifying and hysteretic features. Devices are formed by two junctions, Ti/HfO2 and Co/HfO2. Each junction exhibits highly repetitive hysteretic I-V curves with a sharp transition from a high to a low resistance state (3–4 orders of magnitude jump). The opposite transition (from low to high) is induced by polarity reversal. The rectifying non-crossing characteristics of the I-V branches denote their potential use as a multifunctional device, acting as a built-in rectifier and memory cell in a single device. Based on the phenomenological model description by Zazpe et al. [Appl. Phys. Lett. 103, 073114 (2013)], we propose a circuital equivalent representation supported on switchable rectifying junctions. By exploring different electrode connections, we disentangle the role of the bulk transport in HfO2 devices.Fil: Quinteros, Cynthia Paula. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zaspe, R.. CIC nanoGUNE; EspañaFil: Marlasca, F. G.. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; ArgentinaFil: Golmar, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Casanova, F.. CIC nanoGUNE; España. Fundación Vasca para la Ciencia; EspañaFil: Stoliar, Pablo Alberto. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Centre National de la Recherche Scientifique; Francia. Universite de Nantes; FranciaFil: Hueso, L.. Fundación Vasca para la Ciencia; España. CIC nanoGUNE; EspañaFil: Levy, Pablo Eduardo. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
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