2,583 research outputs found

    Hybrid Architecture for Engineering Magnonic Quantum Networks

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    We show theoretically that a network of superconducting loops and magnetic particles can be used to implement magnonic crystals with tunable magnonic band structures. In our approach, the loops mediate interactions between the particles and allow magnetic excitations to tunnel over long distances. As a result, different arrangements of loops and particles allow one to engineer the band structure for the magnonic excitations. Furthermore, we show how magnons in such crystals can serve as a quantum bus for long-distance magnetic coupling of spin qubits. The qubits are coupled to the magnets in the network by their local magnetic-dipole interaction and provide an integrated way to measure the state of the magnonic quantum network.Comment: Manuscript: 4 pages, 3 figures. Supplemental Material: 9 pages, 4 figures. V2: Published version in PRA: 14 pages + 8 figures. Substantial rearrangement of the content of the previous versio

    A proposito dell\u2019inchiesta della S. Congregazione dell\u2019Indice dei libri proibiti di fine \u2018500

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    Il paper \u2013 diviso in tre parti \u2013 muove dai risultati della \u201cRicerca sull\u2019inchiesta della Congregazione dell\u2019Indice\u201d che ha preso in esame i codici Vaticani Latini che conservano circa 9500 liste di titoli di libri posseduti dai religiosi italiani alla fine del XVI secolo. Roberto Rusconi sviluppa una panoramica introduttiva sulle biblioteche degli ordini religiosi alla fi ne del Cinquecento. Giovanna Granata sfrutta le molteplici potenzialit\ue0 informative dell\u2019Inchiesta, sia in termini di conoscenza di tali biblioteche, sia rispetto alle modalit\ue0 di circolazione delle diverse edizioni. Rosa Marisa Borraccini prende invece in esame un caso di studio come quello del 'Confessionario' di Girolamo da Palermo per dimostrare l\u2019importanza che un testo oggi quasi del tutto sconosciuto aveva all\u2019epoca della sua produzione. This paper \u2013 divided into three sections \u2013 expands upon the work undertaken in \u201cRicerca sull\u2019inchiesta della Congregazione dell\u2019Indice\u201d, which has examined the Codici Vaticani Latini, a collection which conserves around 9.500 lists of volumes owned by Italian monks and clerics at the end of the sixteenth century. Roberto Rusconi offers an introductory overview of the libraries of religious orders at the end of the sixteenth century. Giovanna Granata analyses the findings of the Inchiesta in terms of actual library holdings and in terms of the circulation of different editions. Rosa Marisa Borraccini examines the case study of the \u201cConfessionario\u201d of Girolamo da Palermo to demonstrate the importance certain texts, although now forgotten and largely ignored, had at the time of their production and circulation

    An innovative technique for the investigation of the 4-fold forbidden beta-decay of 50^{50}V

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    For the first time a Vanadium-based crystal was operated as cryogenic particle detector. The scintillating low temperature calorimetric technique was used for the characterization of a 22 g YVO4_4 crystal aiming at the investigation of the 4-fold forbidden non-unique β\beta^- decay of 50^{50}V. The excellent bolometric performance of the compound together with high light output of the crystal makes it an outstanding technique for the study of such elusive rate process. The internal radioactive contaminations of the crystal are also investigated showing that an improvement on the current status of material selection and purification are needed, 235/238^{235/238}U and 232^{232}Th are measured at the level of 28 mBq/kg, 1.3 Bq/kg and 28 mBq/kg, respectively. In this work, we also discuss a future upgrade of the experimental set-up which may pave the road for the detection of the rare 50^{50}V β\beta^- decay

    Cryogenic light detectors with enhanced performance for rare events physics

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    We have developed and tested a new way of coupling bolometric light detectors to scintillating crystal bolometers based upon simply resting the light detector on the crystal surface, held in position only by gravity. This straightforward mounting results in three important improvements: (1) it decreases the amount of non-active materials needed to assemble the detector, (2) it substantially increases the light collection efficiency by minimizing the light losses induced by the mounting structure, and (3) it enhances the thermal signal induced in the light detector thanks to the extremely weak thermal link to the thermal bath. We tested this new technique with a 16 cm2^2 Ge light detector with thermistor readout sitting on the surface of a large TeO2_2 bolometer. The light collection efficiency was increased by greater than 50\% compared to previously tested alternative mountings. We obtained a baseline energy resolution on the light detector of 20~eV RMS that, together with increased light collection, enabled us to obtain the best α\alpha vs β/γ\beta/\gamma discrimination ever obtained with massive TeO2_2 crystals. At the same time we achieved rise and decay times of 0.8 and 1.6 ms, respectively. This superb performance meets all of the requirements for the CUPID (CUORE Upgrade with Particle IDentification) experiment, which is a 1-ton scintillating bolometer follow up to CUORE.Comment: 6 pages, 4 figure

    Background suppression in massive TeO2_2 bolometers with Neganov-Luke amplified light detectors

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    Bolometric detectors are excellent devices for the investigation of neutrinoless double-beta decay (0νββ\nu\beta\beta). The observation of such decay would demonstrate the violation of lepton number, and at the same time it would necessarily imply that neutrinos have a Majorana character. The sensitivity of cryogenic detectors based on TeO2_2 is strongly limited by the alpha background in the region of interest for the 0νββ\nu\beta\beta of 130^{130}Te. It has been demonstrated that particle discrimination in TeO2_2 bolometers is possible measuring the Cherenkov light produced by particle interactions. However an event-by-event discrimination with NTD-based light detectors has to be demonstrated. We will discuss the performance of a highly-sensitive light detector exploiting the Neganov-Luke effect for signal amplification. The detector, being operated with NTD-thermistor and coupled to a 750 g TeO2_2 crystal, shows the ability for an event-by-event identification of electron/gamma and alpha particles. The extremely low detector baseline noise, RMS 19 eV, demonstrates the possibility to enhance the sensitivity of TeO2_2-based 0νββ\nu\beta\beta experiment to an unprecedented level

    Reducing the impact of radioactivity on quantum circuits in a deep-underground facility

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    As quantum coherence times of superconducting circuits have increased from nanoseconds to hundreds of microseconds, they are currently one of the leading platforms for quantum information processing. However, coherence needs to further improve by orders of magnitude to reduce the prohibitive hardware overhead of current error correction schemes. Reaching this goal hinges on reducing the density of broken Cooper pairs, so-called quasiparticles. Here, we show that environmental radioactivity is a significant source of nonequilibrium quasiparticles. Moreover, ionizing radiation introduces time-correlated quasiparticle bursts in resonators on the same chip, further complicating quantum error correction. Operating in a deep-underground lead-shielded cryostat decreases the quasiparticle burst rate by a factor fifty and reduces dissipation up to a factor four, showcasing the importance of radiation abatement in future solid-state quantum hardware

    New experimental limits on the alpha decays of lead isotopes

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    For the first time a PbWO4 crystal was grown using ancient Roman lead and it was run as a cryogenic detector. Thanks to the simultaneous and independent read-out of heat and scintillation light, the detector was able to discriminate beta/gamma interactions with respect to alpha particles down to low energies. New more stringent limits on the alpha decays of the lead isotopes are presented. In particular a limit of T_{1/2} > 1.4*10^20 y at a 90% C.L. was evaluated for the alpha decay of 204Pb to 200Hg

    Clinical and genetic factors associated with kidney tubular dysfunction in a real-life single centre cohort of HIV-positive patients

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    BACKGROUND: Tenofovir (TDF) is one of the most widely used antiretroviral drug. Despite the high degree of tolerability a small percentage of patients experienced alteration in tubular function during TDF use. Intracellular TDF disposition is regulated by ATP-binding cassette (ABC) drug efflux transporters and, a reduced transport activity may be implicated in accumulation of TDF into the cells. The aim of our study was to assess the major determinants of TDF associated tubular dysfunction (KTD) in a real-life setting including the usefulness of single-nucleotide polymorphisms (SNPs) mapping into ABCC2, ABCC4 and ABCC10 genes. METHODS: We retrospectively analyzed all HIV positive patients who were followed at the Infectious Diseases Unit, DIBIC Luigi Sacco, University of Milan from April 2013 to June 2016. All patients treated with TDF who underwent a genotypization for the functional variants mapping in ABCC2 rs717620 (-24 C > T), ABCC4 rs1751034 (3463 A > G) and ABCC10 rs2125739 (T > C) were evaluated. KTD was defined as the presence of urine phosphate wasting and/or proteinuria at 24 h urine analysis. RESULTS: One hundred fifty-eight patients were genotyped, of which 42 (26.6%) experienced signs of KTD. No statistical significant differences were observed among patients with or without KTD regarding age, gender, ethnicity and comorbidities (hypertension and diabetes). The percentage of patients with KTD was higher among those with "GG" genotype at rs1751034 of ABCC4 compared to patients without KTD [6 (14.3%) vs 4 (3.5%), p = 0.01]. No statistical significant differences were observed regarding the distribution of ABCC2 and ABCC10 SNPs. Carriers of "G" allele in homozygous status at rs1751034 of ABCC4 showed a significant association with KTD (Odds Ratio 4.67, 95% CI 1.25-17.46, p = 0.02) in bivariate analysis, but this association was lost in multivariable analysis. A significant association between bone diseases and KTD was observed (Odds Ratio 3.178, 95%CI 1.529-6.603, p = 0.002). CONCLUSIONS: According to our results ABCC4 rs1751034 could be a genetic determinant of KTD; however validation studies are needed for therapy personalization. Noteworthy, a strong association between bone disease and KTD was also observed

    Development of a Li2MoO4 scintillating bolometer for low background physics

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    We present the performance of a 33 g Li2MoO4 crystal working as a scintillating bolometer. The crystal was tested for more than 400 h in a dilution refrigerator installed in the underground laboratory of Laboratori Nazionali del Gran Sasso (Italy). This compound shows promising features in the frame of neutron detection, dark matter search (solar axions) and neutrinoless double-beta decay physics. Low temperature scintillating properties were investigated by means of different alpha, beta/gamma and neutron sources, and for the first time the Light Yield for different types of interacting particle is estimated. The detector shows great ability of tagging fast neutron interactions and high intrinsic radiopurity levels (< 90 \muBq/kg for 238-U and < 110 \muBq/kg for 232-Th).Comment: revised versio

    First bolometric measurement of the two neutrino double beta decay of 100^{100}Mo with a ZnMoO4_4 crystals array

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    The large statistics collected during the operation of a ZnMoO4_4 array, for a total exposure of 1.3 kg \cdot day of 100^{100}Mo, allowed the first bolometric observation of the two neutrino double beta decay of 100^{100}Mo. The observed spectrum of each crystal was reconstructed taking into account the different background contributions due to environmental radioactivity and internal contamination. The analysis of coincidences between the crystals allowed the assignment of constraints to the intensity of the different background sources, resulting in a reconstruction of the measured spectrum down to an energy of \sim300 keV. The half-life extracted from the data is T1/22ν_{1/2}^{2\nu}= [7.15 ±\pm 0.37 (stat) ±\pm 0.66 (syst)] \cdot 1018^{18} y.Comment: 6 pages, 2 figure, Accepted for publication in Journal of Physics G: Nuclear and Particle Physic
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