508 research outputs found
Persistent oscillations after quantum quenches in d dimensions
No full textWe obtain analytical results for the time evolution of local observables in systems undergoing quantum quenches in d spatial dimensions. For homogeneous systems we show that oscillations undamped in time occur when the state produced by the quench includes single-quasiparticle modes and the observable couples to those modes. In particular, a quench of the transverse field within the ferromagnetic phase of the Ising model produces undamped oscillations of the order parameter when d>1. For the more general case in which the quench is performed only in a subregion of the whole d-dimensional space occupied by the system, the time evolution occurs inside a light cone spreading away from the boundary of the quenched region as time increases. The additional condition for undamped oscillations is that the volume of the quenched region is extensive in all dimensions
Isovector and hidden-beauty partners of the X(3872)
No full text4 pagesThe isovector partners of the X(3872), recently found at BES III, Belle and CLEO-c were predicted in a simple model based on the chromomagnetic interaction among quarks (H. Hogaasen, J-M. Richard and P. Sorba, Phys. Rev. D73, 054013, 2006). The extension to the hidden-beauty sector is discussed
Interface in presence of a wall. Results from field theory
No full textWe consider three-dimensional statistical systems at phase coexistence in the half-volume with boundary conditions leading to the presence of an interface. Working slightly below the critical temperature, where universal properties emerge, we show how the problem can be studied analytically from first principles, starting from the degrees of freedom (particle modes) of the bulk field theory. After deriving the passage probability of the interface and the order parameter profile in the regime in which the interface is not bound to the wall, we show how the theory accounts at the fundamental level also for the binding transition and its key parameter
RF potentials analysis using TOPICA
No full textRadio-frequency (RF) heating is fully dependent on edge plasma conditions and particularly on the acceleration of charged particles which can damage the antennas and surroundings. Rectified RF field induces drifts on ions that can hit the first wall, causing hot spots, sputtering, impurities, fuel dilution and, eventually, disruption. These phenomena mainly depend on the antenna geometry and materials, on the plasma density profile at the edge and on the connection patterns. The heat flux attributed to accelerated ions is somehow proportional to the RF potential in front of the antenna. Because of this, the understanding of the RF potential generation in front of the antenna is crucial for every high RF power systems, in order to predict the deleterious particle flux and therefore mitigate its effect by means of a proper design. The TOPICA code, an innovative tool realized for the analysis and design of ICRH and LH antennas, has been upgraded to evaluate the RF potential in front of the antenna. The solution of the Maxwell's equations in plasma combined with the RF field map at the plasma edge (standard outputs of TOPICA calculation) allow for the computation of the RF fields also in the plasma region. A new TOPICA module has been developed to account for a rigorous procedure to obtain the RF potentials and RF potential mitigation techniques through antenna geometrical modifications have been studied and will be presented
La parafrasi anticofrancese del salmo 44 (Eructavit cor meum)
No full textIl lavoro è volto all’allestimento dell’edizione critica della parafrasi anticofrancese del salmo 44 («Eructavit cor meum»), composta sul finire del XII secolo per Maria di Champagne e testimoniata oggi da 20 manoscritti.
Il primo capitolo si concentra sulla definizione del contesto storico e culturale in cui si origina l’opera: si sintetizzano i contenuti e si approfondisce la dedica alla contessa di Champagne, sono presentati gli elementi su cui basare una datazione e si approfondiscono le proposte di attribuzione che nel tempo sono state avanzate per l’Eructavit, con particolare attenzione all’attribuzione a Adam de Perseigne. Si aggiunge inoltre la scoperta di una singolare affinità tra un passo dell’«Eructavit» e uno del «Chronicon» di Robert de Saint-Marien, finora non notato dagli studi, che potrebbe indicare una possibile provenienza da Auxerre dell’autore. Si passa, in seguito, a collocare l’«Eructavit» all’interno della produzione volgare di derivazione biblica del XII secolo, per concludere il capitolo con una rassegna ragionata e commentata della bibliografia critica dedicata all’opera, al fine di approfondirne il valore letterario nelle sue relazioni con opere di ambito sia cortese, sia religioso.
A questa sezione introduttiva segue una descrizione dettagliata di ciascuno dei testimoni conosciuti, completa di datazione e localizzazione. Successivamente, si affronta lo studio della tradizione dal punto di vista testuale, su cui sarà fondata l’edizione critica. A partire da una collazione completa di tutti i testimoni, si sono individuati tre principali gruppi di manoscritti: il primo, chiamato α, è caratterizzato dalla prevalente provenienza piccarda dei codici contenuti, mentre il secondo, β, è meno omogeneo sotto questo punto di vista. Il terzo, γ, infine, parrebbe derivare principalmente da una versione del testo di α, ma con numerosi punti di contatto con β per via di contaminazione, di conseguenza difficilmente collocabile nello stemma. In aggiunta, si è ritenuto di individuare un archetipo a partire dall’errore di datazione del profeta Davide a circa 700 anni prima di Cristo, contraddetta da parte della tradizione stessa dell’«Eructavit» in un altro punto dell’opera e non supportata da alcuna altra fonte medievale che sia stata possibile consultare nel corso del lavoro.
Come strumento d’ausilio all’interpretazione dell’opera e in ottica di conoscenza del testimone, nel capitolo che segue si fornisce uno studio dei tratti grafici, fonetici e morfologici del codice siglato I che si è scelto di usare come manoscritto di riferimento per l’aspetto linguistico dell’edizione. Anche la lingua dell’autore è stata indagata a partire dal lessico e dai dati reperibili dalle rime, tuttavia con risultati poco significativi per quanto riguarda una sua possibile localizzazione.
Infine, è presentato il testo critico, allestito in ottica ricostruttiva e corredato di un ricco apparato di varianti sostanziali. Nelle note di commento si chiariscono le ragioni della constitutio textus e della scelta tra le lezioni nei casi in cui lo stemma non venga in aiuto all’editore. Inoltre, sempre nelle note si trovano rimandi alle fonti che è stato possibile individuare e varie osservazioni di natura interpretativa, storica e letteraria volti a illustrare gli aspetti di non immediata comprensione dell’opera. La traduzione che segue va ugualmente compresa tra gli strumenti di sussidio all’interpretazione, naturalmente di più ampio respiro rispetto alle note di commento puntuale. Infine, un formario lemmatizzato e un indice dei nomi propri e dei toponimi raccolgono esaustivamente tutte le forme presenti nel testo, per facilitare ricerche lessicali o tematiche, o per esplicitare eventuali aspetti di interpretazione morfo-sintattica non messi in luce nelle note o nella traduzione.The aim of this work is to prepare a critical edition of the Old French paraphrase of Psalm 44 («Eructavit cor meum»), composed at the end of the 12th century for Marie de Champagne.
The first chapter explores the historical and cultural context in which the paraphrase originated: it summarises the content of the work, examines the dedication to the Countess of Champagne, and reviews the hypothesis regarding its dating and attribution. Particular attention is given to the attribution to Adam de Perseigne, which is critically analysed and ultimately dismissed as unfounded, based on the most recent research. Furthermore, a previously unnoticed connection between a passage from the «Eructavit» and one from Robert de Saint-Marien’s «Chronicon» is highlighted, suggesting a possible origin of the author from Auxerre. The chapter also situates the «Eructavit» within the 12th-century tradition of vernacular biblical adaptations and concludes with a thorough review of the critical bibliography on the work.
The second chapter provides a detailed description of the 20 known manuscripts, including their dating and origin when identifiable.
The third chapter focuses on the textual tradition, establishing the foundation for the following critical edition. A collation of all witnesses reveals three principal groups of manuscripts. The first group (α) is primarily associated with Picardian origins, while the second (β) is less regionally uniform. The third group (γ) appears to derive largely from a version of α but shows significant contamination with β, making its placement in the stemma codicum challenging. Additionally, the presence of a notable dating error regarding King David – placed approximately 700 years before Christ, but in contradiction with an other section of the text and unsupported by the medieval sources – provides evidence of an archetype.
To aid in the interpretation of the work, the fourth chapter examines the graphic, phonetic, and morphological features of manuscript I, selected as the reference for the linguistic aspects of the edition. The author’s language is also analysed through the lexicon and rhymes, though without remarkable results regarding its geographic localization.
Finally, the critical edition of the text is presented, aimed at reconstructing the original version and accompanied by a comprehensive apparatus of variant readings. The commentary notes that follow explain the constitutio textus, providing the reasons for editorial choices among various variants, especially in cases where the stemma fails to guide the editor decisively. These notes also include references to biblical, patristic and medieval Latin sources identified during the research, along with interpretative, historical and literary observations to clarify elements of the text that may not be immediately apparent. Additionally, a translation is offered as an interpretative tool with a broader scope than the notes. The thesis concludes with a lemmatized index of all forms found in the text.Ce travail à pour objectif de présenter l’édition critique de la paraphrase en ancien français du psaume 44 («Eructavit cor meum»), composée pour Marie de Champagne à la fin du XIIe siècle et aujourd’hui attestée par 20 manuscrits.
Le premier chapitre définit le contexte historique et culturel dans lequel l’œuvre a été rédigée : il contient un résumé du texte et une analyse de la dédicace à la comtesse de Champagne. Des éléments de datation sont présentés, qui, bien que non univoques ni particulièrement nets, situent probablement la composition de l’œuvre entre les années 1183 et 1187. Sur cette base, sont examinées les hypothèses d’attribution avancées jusqu’ici, en réservant une attention toute particulière à l’attribution à Adam de Perseigne, la quelle, bien que généralement acceptée par les chercheurs, a été remise en question à la lumière des recherches les plus récentes. Plus particulièrement, une affinité non remarquée jusqu’à présent entre un passage de l’«Eructavit» et un extrait du «Chronicon» de Robert de Saint-Marien est ici mise en évidence : elle pourrait indiquer une origine possible de l’auteur dans l’auxerrois. Le chapitre prend ensuite en considération la place de l'«Eructavit» dans la production vernaculaire de dérivation biblique au XIIe siècle. Il se termine par un recensement raisonné et commenté de la bibliographie critique consacrée à l’ouvrage, mettant en lumière sa valeur littéraire, notamment ses relations avec des œuvres d’origine à la fois courtoise et religieuse.
Ensuite, après une description détaillée de chacun des témoins connus, avec leur datation et leur localisation, nous passons à l’étude de la tradition textuelle, en définissant la base sur laquelle sera construite l’édition critique. À partir d’une collation complète de tous les témoins, trois groupes principaux de manuscrits ont été identifiés : le premier, appelé ici α, se distingue par la provenance picarde de la majorité des manuscrits qu’il contient, tandis que le second, β, présente moins d’homogénéité à cet égard. Le troisième, γ, semble dériver d’une version du texte issue d’α, mais montre de nombreux points de contact avec β, des contacts certainement dus à la contamination. Une conjecture sur l’existence d’un archétype est aussi avancée à partir d’une erreur de datation concernant le prophète David, qui est dit avoir vécu environ 700 ans avant Jésus-Christ. Cette erreur est contredite par la tradition même de l'«Eructavit» (comme le montrent d’autres passages à l’intérieur du texte) et n’est soutenue par aucune autre source médiévale consultée.
Afin de mieux connaître le témoin utilisé comme manuscrit de base pour la graphie du texte critique et pour faciliter l’interprétation de l’œuvre, le chapitre suivant propose une étude des caractéristiques graphiques, phonétiques et morphologiques du manuscrit siglé I. La langue de l’auteur est également analysée à partir du lexique et des données disponibles dans les rimes, les résultats sont pourtant peu significatifs pour ce qui concerne la possibilité de parvenir à une localisation.
Suit enfin le texte critique, établi selon une perspective reconstructive et accompagné d’un riche apparat de variantes de nature substantielle (non purement graphiques ou linguistiques). Les notes de commentaire qui suivent donnent raison de la constitutio textus et des choix effectués entre plusieurs variantes, chaque fois que le stemma codicum n’est pas à mesure d’aider l’éditeur. Les notes signalent aussi les références faites aux sources bibliques, patristiques ou latines contemporaines qu’il nous a été possible d’identifier, ainsi que plusieurs commentaires interprétatifs, historiques et littéraires éclaircissant les aspects du texte qui ne sont pas d’une compréhension immédiate. Une traduction est également proposée, conçue comme un outil d’interprétation d’une portée plus large que les notes. A la fin de la thèse a été fournie une lemmatisation exhaustive de toutes les formes présentes dans le texte
Se-doping dependence of the transport properties in CBE-grown InAs nanowire field effect transistors
No full textWe investigated the transport properties of lateral gate field effect transistors (FET) that have been realized by employing, as active elements, (111) B-oriented InAs nanowires grown by chemical beam epitaxy with different Se-doping concentrations. On the basis of electrical measurements, it was found that the carrier mobility increases from 103 to 104 cm2/(V × sec) by varying the ditertiarybutyl selenide (DtBSe) precursor line pressure from 0 to 0.4 Torr, leading to an increase of the carrier density in the transistor channel of more than two orders of magnitude. By keeping the DtBSe line pressure at 0.1 Torr, the carrier density in the nanowire channel measures ≈ 5 × 1017 cm-3 ensuring the best peak transconductances (> 100 mS/m) together with very low resistivity values (70 Ω × μm) and capacitances in the attofarad range. These results are particularly relevant for further optimization of the nanowire-FET terahertz detectors recently demonstrated
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