3,557 research outputs found

    Entanglement sharing in EϵE\otimes\epsilon Jahn-Teller model in the presence of a magnetic field

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    We discuss the ground state entanglement of the EϵE\otimes\epsilon Jahn-Teller model in the presence of a strong transverse magnetic field as a function of the vibronic coupling strength. A complete characterization is given of the phenomenon of entanglement sharing in a system composed by a qubit coupled to two bosonic modes. Using the residual II-tangle, we find that three-partite entanglement is significantly present in the system in the parameter region near the bifurcation point of the corresponding classical model

    Optimization of RPCs read-out panel with electromagnetic simulation

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    With the upgrade of the RPCs [1]-[2] and the increase of its performances, the study and the optimization of the read-out panel is necessary in order to maintain the signal integrity and to reduce the intrinsic crosstalk. Through Electromagnetic Simulation, performed with CST Studio Suite, new panels design are tested and their crosstalk property are studied. The behavior of different type of panel is shown, in particular a panel with the decoupling strip connected through their characteristic impedance to the ground plane is simulated

    Entanglement in Many-Body Systems

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    The recent interest in aspects common to quantum information and condensed matter has prompted a prosperous activity at the border of these disciplines that were far distant until few years ago. Numerous interesting questions have been addressed so far. Here we review an important part of this field, the properties of the entanglement in many-body systems. We discuss the zero and finite temperature properties of entanglement in interacting spin, fermionic and bosonic model systems. Both bipartite and multipartite entanglement will be considered. At equilibrium we emphasize on how entanglement is connected to the phase diagram of the underlying model. The behavior of entanglement can be related, via certain witnesses, to thermodynamic quantities thus offering interesting possibilities for an experimental test. Out of equilibrium we discuss how to generate and manipulate entangled states by means of many-body Hamiltonians.Comment: 61 pages, 29 figure

    Ageing test of the ATLAS RPCs at X5-GIF

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    An ageing test of three ATLAS production RPC stations is in course at X5-GIF, the CERN irradiation facility. The chamber efficiencies are monitored using cosmic rays triggered by a scintillator hodoscope. Higher statistics measurements are made when the X5 muon beam is available. We report here the measurements of the efficiency versus operating voltage at different source intensities, up to a maximum counting rate of about 700Hz/cm^2. We describe the performance of the chambers during the test up to an overall ageing of 4 ATLAS equivalent years corresponding to an integrated charge of 0.12C/cm^2, including a safety factor of 5.Comment: 4 pages. Presented at the VII Workshop on Resistive Plate Chambers and Related Detectors; Clermont-Ferrand October 20th-22nd, 200

    Wax: A benign hydrogen-storage material that rapidly releases H2-rich gases through microwave-assisted catalytic decomposition

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    Hydrogen is often described as the fuel of the future, especially for application in hydrogen powered fuel-cell vehicles (HFCV’s). However, its widespread implementation in this role has been thwarted by the lack of a lightweight, safe, on-board hydrogen storage material. Here we show that benign, readily-available hydrocarbon wax is capable of rapidly releasing large amounts of hydrogen through microwave-assisted catalytic decomposition. This discovery offers a new material and system for safe and efficient hydrogen storage and could facilitate its application in a HFCV. Importantly, hydrogen storage materials made of wax can be manufactured through completely sustainable processes utilizing biomass or other renewable feedstocks

    Development of gaseous particle detectors based on semi-conductive electrode plates

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    A new kind of particle detector based on RPC-like structure was developed. Semi-conductive electrodes with resistivity ρ up to 108 Ω·cm have been used to improve the RPC rate capability. The aim is to obtain a detector with sub-nanosecond time resolution capable of working in a high-rate environment (rate capability of the order of MHz/cm2). In this paper the results on two different detector structures are presented: one with 1 mm gas gap and both SI(Semi-Insulating)- GaAs electrodes (ρ ∼ 108 Ω·cm), and the other characterized by 1.5 mm gas gap, one SI-GaAs electrode and one intrinsic silicon electrode (ρ ∼ 104 Ω · cm)