6,506 research outputs found

    Revealing quantum statistics with a pair of distant atoms

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    Quantum statistics have a profound impact on the properties of systems composed of identical particles. In this Letter, we demonstrate that the quantum statistics of a pair of identical massive particles can be probed by a direct measurement of the exchange symmetry of their wave function even in conditions where the particles always remain spatially well separated and thus the exchange contribution to their interaction energy is negligible. We present two protocols revealing the bosonic or fermionic nature of a pair of particles and discuss possible implementations with a pair of trapped atoms or ions.Comment: 4+13 pages, v2 corresponds to the version published by PR

    A simple abstraction of arrays and maps by program translation

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    We present an approach for the static analysis of programs handling arrays, with a Galois connection between the semantics of the array program and semantics of purely scalar operations. The simplest way to implement it is by automatic, syntactic transformation of the array program into a scalar program followed analysis of the scalar program with any static analysis technique (abstract interpretation, acceleration, predicate abstraction,.. .). The scalars invariants thus obtained are translated back onto the original program as universally quantified array invariants. We illustrate our approach on a variety of examples, leading to the " Dutch flag " algorithm

    Integration of nonsmooth 2-forms: From Young to Itô and Stratonovich

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    We show that geometric integrals of the type ∫Ωfdg1∧dg2 can be defined over a two-dimensional domain Ω when the functions f, g1, g2:R2→R are just Hölder continuous with sufficiently large Hölder exponents and the boundary of Ω has sufficiently small dimension, by summing over a refining sequence of partitions the discrete Stratonovich or Itô type terms. This leads to a two-dimensional extension of the classical Young integral that coincides with the integral introduced recently by R. Züst. We further show that the Stratonovich-type summation allows to weaken the requirements on Hölder exponents of the map g=(g1,g2) when f(x)=F(x,g(x)) with F sufficiently regular. The technique relies upon an extension of the sewing lemma from Rough paths theory to alternating functions of two-dimensional oriented simplices, also proven in the paper

    Scaling Bounded Model Checking By Transforming Programs With Arrays

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    Bounded Model Checking is one the most successful techniques for finding bugs in program. However, model checkers are resource hungry and are often unable to verify programs with loops iterating over large arrays.We present a transformation that enables bounded model checkers to verify a certain class of array properties. Our technique transforms an array-manipulating (ANSI-C) program to an array-free and loop-free (ANSI-C) program thereby reducing the resource requirements of a model checker significantly. Model checking of the transformed program using an off-the-shelf bounded model checker simulates the loop iterations efficiently. Thus, our transformed program is a sound abstraction of the original program and is also precise in a large number of cases - we formally characterize the class of programs for which it is guaranteed to be precise. We demonstrate the applicability and usefulness of our technique on both industry code as well as academic benchmarks

    Control of Fusarium head blight and accumulation of deoxynivalenol in durum wheat grain, semolina and bran

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    To verify the effects of E.B.I. fungicides on Fusarium head blight and to determine the deoxynivalenol (DON) content in grain, semolina and bran, three separate trials were carried out in fields near Bologna (Italy) on susceptible durum wheat varieties artificially inoculated with F. graminearum and F. culmorum, responsible of this disease. Treatments with bromuconazole, prochloraz, tebuconazole applied in the field had significantly reduced the FHB disease incidence and severity by 56% and 73% respectively and the numbers of kernels infected by F. graminearum and F. culmorum by 66.6%. These products reduced also DON content in kernels, semolina and bran, compared to the non treated samples. The correlation (r) between DON and the incidence of F. graminearum and F. culmorum infected kernels was in the Original Sample (OS) 0.90

    Catalysis in non--local quantum operations

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    We show how entanglement can be used, without being consumed, to accomplish unitary operations that could not be performed with out it. When applied to infinitesimal transformations our method makes equivalent, in the sense of Hamiltonian simulation, a whole class of otherwise inequivalent two-qubit interactions. The new catalysis effect also implies the asymptotic equivalence of all such interactions.Comment: 4 pages, revte

    Power calculation for gravitational radiation: oversimplification and the importance of time scale

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    A simplified formula for gravitational-radiation power is examined. It is shown to give completely erroneous answers in three situations, making it useless even for rough estimates. It is emphasized that short timescales, as well as fast speeds, make classical approximations to relativistic calculations untenable.Comment: Three pages, no figures, accepted for publication in Astronomische Nachrichte

    Cathode Active Material Recycling from Spent Lithium Batteries: A Green (Circular) Approach Based on Deep Eutectic Solvents

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    The transition to a circular economy vision must handle the increasing request of metals required to satisfy the battery industry; this can be obtained by recycling and feeding back secondary raw materials recovered through proper waste management. Here, a novel and green proof-of-concept was developed, based on deep eutectic solvents (DESs) to fully and easily recover valuable metals from various cathode active materials, including LiMn2O4, LiNi0.5Mn1.5O4, and LiNi0.8Co0.2O2. DES composed of choline chloride and lactic acid could leach Li, Mn, Co, and Ni, achieving efficiency of 100 % under much milder conditions with respect to the previous literature. For the first time, to our best knowledge, a two-step approach was reported in the case of LiNi0.8Co0.2O2 for selective recovery of Li, Co, and Ni with high yield and purity. Furthermore, other cathode components, namely aluminum current collector and binder, were found to be not dissolved by the proposed DES, thus making a simple separation from the active material possible. Finally, this strategy was designed to easily regenerate and reuse the leaching solvents for more than one extraction, thus further boosting process sustainability

    Rilievo in tempo reale di difetti superficiali su corpi in movimento a velocità elevata con ultrasuoni senza contatto

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    Il rilievo di difetti superficiali durante le ispezioni periodiche è importante poiché in genere le sollecitazioni sono maggiori in superficie e possono accelerare la crescita delle discontinuità. I difetti superficiali possono essere rilevati utilizzando alcuni metodi tradizionali di controllo non distruttivo, quali correnti indotte, liquidi penetranti, polveri magnetiche ed ultrasuoni. Alcuni tra questi metodi possono essere usati solo in condizioni statiche; gli altri presentano delle limitazioni per l’ispezione dinamica. I progressi recenti nel campo dei sensori ultrasonori senza contatto ci hanno permesso di sviluppare un sistema semplice per l’ispezione in tempo reale di corpi in movimento a velocità elevata. Nel lavoro viene presentata la possibilità di usare, col sistema sviluppato, due metodologie, basate sugli ultrasuoni generati e ricevuti senza contatto con la struttura, per rilevare difetti superficiali su corpi in movimento a 100 km/h, così da poter effettuare l’ispezione anche in servizio. Una metodologia, basata sull’uso di laser e trasduttori senza contatto, utilizza i vantaggi delle onde superficiali generate con il laser; l’analisi viene fatta sull’onda riflessa, creata dall’interazione dell’onda superficiale con il difetto. Lo spessore superficiale ispezionato è selezionabile dalla lunghezza d’onda dell’onda superficiale generata. L’altra metodologia, basata sull’uso di trasduttori senza contatto, sfrutta gli svantaggi della trasmissione degli ultrasuoni all’interfaccia aria/metallo; l’analisi viene fatta sulla diffrazione dell’onda riflessa dalla superficie. L’esecuzione delle ispezioni risulta semplice con entrambe le tecniche. I risultati sperimentali indicano una buona efficienza delle due metodologie proposte per il rilievo, in tempo reale, di difetti superficiali su corpi in movimento ad alta velocità
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