107 research outputs found
Detection of Quantum Phase Transitions with a Lee-Yang Formalism and Many-Body Algorithms
No full textPhase transitions in many-body quantum systems arise from the collective behaviour of many degrees of freedom. For many interacting quantum many-body systems, it remains challenging to determine their phase diagram due to the exponential growth in the Hilbert space size and the difficulty of existing numerical techniques to tackle generic interacting quantum many-body systems.
In this thesis, we combine state-of-the-art numerical techniques with an approach to symmetrybreaking phase transitions inspired by the works of Lee and Yang on the zeros of partition functions in the complex plane. Specifically, we study the behaviour and distribution of zeros of the momentgenerating function of the relevant order parameters to locate the phase transitions. We refer to these zeros as Lee-Yang zeros. Our approach involves using tensor networks and neural quantum states as variational states to describe the ground states or finite temperature density matrices of the systems studied. While tensor networks allow for a direct evaluation of the moment-generating function, and therefore a direct determination of the position of these Lee-Yang zeros, this is not possible for neural quantum states. Therefore, we also present a method that uses high cumulants of the order parameter combined with knowledge about the symmetries of the Lee-Yang zeros to estimate their locations. By extrapolating the distance from the origin to these zeros to the thermodynamic limit, the presence of a phase transition can be determined. Using this Lee-Yang formalism, we map out the phase diagram of the transverse field Ising model and a fermionic chain, thereby showing its practical applicability to specific quantum many-body models.
Also using neural quantum states and tensor networks, we determine the phase diagram of a tetramerized antiferromagnetic spin-1/2 J₁-J₂ Heisenberg model on the square lattice. Without relying on our Lee-Yang formalism, we are able to trace out the phase diagram using conventional means, such as studying the susceptibility, spin structure factor and the many-body gap. This model, which has been recently realized in experiment, exhibits an intriguing competition between conventional magnetically ordered phases and a higher-order symmetry protected topological phase. By mapping out its phase diagram, we contribute to guiding experiments towards the parameter regimes of interest
Samuel Beckett and the Writers of Port-Royal
No full textIt has been observed that ‘the literary influences on Beckett have been far more important than has been acknowledged, and more important indeed, than the philosophical influences’ (Smith 2002: 3). The truth of this statement is evidenced by the description that scholars have given of Samuel Beckett’s relationship to seventeenth century French classicism. To date, critical interest has been limited for the most part to the figure of the philosopher René Descartes on the (fragile) grounds that Beckett was exclusively concerned with the Cartesian imperative of clarity and order, the fundamental dualism between body and mind, and Nominalism.
Together with the assumption that Beckett’s vision was essentially Cartesian, his literary filiation with Pascal was suggested by critics, but only in terms of Beckett’s formal approach to the theatre. In his short article on En attendant Godot in 1953, the playwright Jean Anouilh was among the first reviewers to suggest that Beckett’s drama synthesizes the encounter between ‘classicism’ and a ‘modern’ form of art. It is well known that Beckett retained a lifelong admiration for Pascal – indeed, Pascal was one of his ‘old chestnuts’ (Knowlson 1997: 653). Little attention has been paid, however, to the originality of Pascal’s thought, the specific nature of his prose, and the impact these might have had upon Beckett’s mature work, especially the trilogy and the subsequent short prose. Yet, in the literary and philosophical context of post-war France, Beckett’s filiation with Pascal, their corresponding preoccupations, were evident to his contemporaries, who identified Pascal as an underlying presence in his works
Pascal Quignard : music and poetics of default
No full textBrassage de savoirs, retour des formes anciennes, esthétique du minuscule, éclatement des genres, moi qui se fond dans la graphie, l’écriture de Pascal Quignard caractérise les enjeux de la littérature contemporaine. En ce sens, la poétique de la défaillance devient l’outil herméneutique qui donne à l’œuvre sa singularité. Cette poétique met en relief une quête spéculative centrée sur la hantise des origines et le rapport problématique avec le langage, le savoir, l’Histoire, la musique, la pensée et l’autobiographie. Dans un premier temps, nous abordons la défaillance langagière. La langue est acquise et cette acquisition nous soumet à une forme de domination sociale. La littérature quignardienne est vouée à désamorcer ce lien grâce au travail de l’auteur qui écrit en lisant. Il en résulte une œuvre qui détient un appareil intertextuel complexe et une écriture à la fois récapitulative et fragmentaire que l’étude des noms, des contes et des rêves met en lumière. Dans un deuxième temps, nous étudions la défaillance sonore. Il s’agit d’analyser l’expérience de la musique en tant que négativité, son rôle dans le milieu concentrationnaire, sa place à l’ère de la reproduction technique, son rapport au silence, à l’indicible et à la mort. Pour finir, nous examinons les raisons de l’hermétisme de cette œuvre et de son obscurité, ainsi que les difficultés qui s’en dégagent. Œuvre qui inclut son propre cheminement herméneutique, nous interrogeons à la fois la place du critique littéraire qu’elle invente et la place du sujet dans le cadre du renouvellement des écritures de soi.The stirring of knowledge, the return of old forms, the aesthetics of smallness, the explosion of genres, the ’I’ that is based on graphics: the works of Pascal Quignard characterise what is at stake in contemporary literature. In this sense, the poetics of default becomes the hermeneutic tool that gives the work its singularity. This poetics highlights a speculative quest focused on the obsession of origins and on the problematic relation with language, knowledge, History, music, thought and autobiography. First, we shall analyse the default of language. Language is acquired and acquiring it makes us undergo a form of social domination. Quignardian literature is destined to disarm this bound thanks to the work accomplished by an author who writes while reading. The result is a work that encompasses a complex intertextual mechanism and a both recapitulative and fragmentary style of writing that the study on names, tales and dreams highli! ghts. Secondly, we shall study the default of sound. We will mean to analyse the experience of music as negativity, its role in the concentration camps, its place in the era of technical reproduction, its relation to silence, to the unutterable and to death. Finally, we shall examine the reasons for the hermetism and obscurity of this work, as well as the difficulties that arise thereof. Since this work includes its own hermeneutic development, we shall question the role of both the literary critic invented by this work and of the subject in the context of the renewal of this style of writing oneself
First observation of Bs → J/ψf0(980) decays
No full textUsing data collected with the LHCb detector in proton–proton collisions at a centre-of-mass energy of 7 TeV, the hadronic decay is observed. This CP eigenstate mode could be used to measure mixing-induced CP violation in the system. Using a fit to the π+π− mass spectrum with interfering resonances gives . In the interval ±90 MeV around 980 MeV, corresponding to approximately two full f0 widths we also find , where in both cases the uncertainties are statistical and systematic, respectively
Semi-Supervised Image Classification based on a Multi-Feature Image Query Language
No full textThe area of Content-Based Image Retrieval (CBIR) deals with a wide range of research disciplines. Being closely related to text retrieval and pattern recognition, the probably most serious issue to be solved is the so-called \semantic gap". Except for very restricted use-cases, machines are not able to recognize the semantic content of digital images as well as humans.
This thesis identifies the requirements for a crucial part of CBIR user interfaces, a multimedia-enabled query language. Such a language must be able to capture the user's
intentions and translate them into a machine-understandable format. An approach to tackle this translation problem is to express high-level semantics by merging low-level image features. Two related methods are improved for either fast (retrieval) or accurate(categorization) merging.
A query language has previously been developed by the author of this thesis. It allows the formation of nested Boolean queries. Each query term may be text- or content-based and the system merges them into a single result set. The language is extensible by arbitrary new feature vector plug-ins and thus use-case independent.
This query language should be capable of mapping semantics to features by applying machine learning techniques; this capability is explored. A supervised learning algorithm based on decision trees is used to build category descriptors from a training set. Each resulting \query descriptor" is a feature-based description of a concept which is comprehensible and modifiable. These descriptors could be used as a normal query and return a result set with a high CBIR based precision/recall of the desired category. Additionally, a method for normalizing the similarity profiles of feature vectors has been
developed which is essential to perform categorization tasks.
To prove the capabilities of such queries, the outcome of a semi-supervised training session with \leave-one-object-out" cross validation is compared to a reference system. Recent work indicates that the discriminative power of the query-based descriptors is similar and is likely to be improved further by implementing more recent feature vectors
Reinardus 2
No full textItems include are:Jean Batany, Renart au XVe siècle: une réécriture du Livre des Bêtes de Raymond Lulle par Jean Juvénal des Ursins; Roger Bellon, L'art du remaniement. Les aventures de Primaut le loup dans les mss A et C; Issachar Ben-Ami, Le monde sacré et animal: contenu et message; Anne Cobby, The Fabliau of Le Prestre et le Chevalier: aspects of illumination and reflection; Jean Lacroix, Du Je à l'Autre ou: Le pacte autobiographique de la fable des animaux-qui-parlent: Rainaldo e Lesengrino; Brian Levy, Leading a merry dance: Le rondel des fabliaux; Marie-Thérèse Lorcin, Les revenants dans les fabliaux; Gianni Mombello, Un Recueil anonyme (Ph.-B. Moreau de Mauour?); Jean-Marc Pastré, Zoomorphisme et typologie littéraire: le personnage de Kunin dans le Reinhart Fuchs; Jacques Ribard, Et si les fabliaux n'etaient pas des contes à rire?; Luigi Sasso, La questione del genere nel Detto del gatto lupesco; Alain-Julien Surdel, Divertissement pascal et latinité médiévale. L'Ecbasis cuiusdam captivi per tropologiam; Patrice Uhl, Notes sur le Lignage du Limeçons armés dans les Fatrasies d'Arras; Erwin Verzandvoort, The Dutch Chapbooks of Reynaert de Vos and their Illustrations; Isabelle Weill, La Parodie de l'énonciation épique dans le Roman de Renart; Haijo J. Westra, The speech of animals in the Ysengrimus and the subversion of a Christian hierarchy of discourse; Charity Cannon Willard, Le bon chien Souillard; Book Review; Illustrations. See for the T of C: http://www.hull.ac.uk/Hull/FR_Web/content2.html.Language note: Bilingual: English/FrenchEdited by Brian Levy & Paul Wacker
The Impact of Advanced Glycation End-Products (AGEs) on Proliferation and Apoptosis of Primary Stem Cells: A Systematic Review
No full textStem cell-based regenerative therapies hold great promises to treat a wide spectrum of diseases. However, stem cell engraftment and survival are still challenging due to an unfavorable transplantation environment. Advanced glycation end-products (AGEs) can contribute to the generation of these harmful conditions. AGEs are a heterogeneous group of glycated products, nonenzymatically formed when proteins and/or lipids become glycated and oxidized. Our typical Western diet as well as cigarettes contain high AGEs content. AGEs are also endogenously formed in our body and accumulate with senescence and in pathological situations. Whether AGEs have an impact on stem cell viability in regenerative medicine remains unclear, and research on the effect of AGEs on stem cell proliferation and apoptosis is still ongoing. Therefore, this systematic review provides a clear overview of the effects of glycated proteins on cell viability in various types of primary isolated stem cells used in regenerative medicine.Figures were created using images from Servier Medical Art Commons Attribution 3.0 Unported License (http://smart.servier.com). Servier Medical Art by Servier is licensed under a Creative Commons Attribution 3.0 Unported License. This work was supported by a Bijzonder onderzoeksfonds (BOF) grant from Hasselt University (grant number: 16NI05BOF). HB benefits from an aspirant PhD mandate (grant number: 1154120N) of the `Research Foundation-Flanders' (fonds voor wetenschappelijk onderzoek (FWO)). PG is also supported by the FWO (grant numbers: 12U7718N and 1502120N).Bito, V (corresponding author), Hasselt Univ, Biomed BIOMED Res Inst, Agoralaan Bldg C, B-3590 Diepenbeek, Belgium.
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Pascal Quignard : musique et poétique de la défaillance
No full textThe stirring of knowledge, the return of old forms, the aesthetics of smallness, the explosion of genres, the ’I’ that is based on graphics: the works of Pascal Quignard characterise what is at stake in contemporary literature. In this sense, the poetics of default becomes the hermeneutic tool that gives the work its singularity. This poetics highlights a speculative quest focused on the obsession of origins and on the problematic relation with language, knowledge, History, music, thought and autobiography. First, we shall analyse the default of language. Language is acquired and acquiring it makes us undergo a form of social domination. Quignardian literature is destined to disarm this bound thanks to the work accomplished by an author who writes while reading. The result is a work that encompasses a complex intertextual mechanism and a both recapitulative and fragmentary style of writing that the study on names, tales and dreams highli! ghts. Secondly, we shall study the default of sound. We will mean to analyse the experience of music as negativity, its role in the concentration camps, its place in the era of technical reproduction, its relation to silence, to the unutterable and to death. Finally, we shall examine the reasons for the hermetism and obscurity of this work, as well as the difficulties that arise thereof. Since this work includes its own hermeneutic development, we shall question the role of both the literary critic invented by this work and of the subject in the context of the renewal of this style of writing oneself.Brassage de savoirs, retour des formes anciennes, esthétique du minuscule, éclatement des genres, moi qui se fond dans la graphie, l’écriture de Pascal Quignard caractérise les enjeux de la littérature contemporaine. En ce sens, la poétique de la défaillance devient l’outil herméneutique qui donne à l’œuvre sa singularité. Cette poétique met en relief une quête spéculative centrée sur la hantise des origines et le rapport problématique avec le langage, le savoir, l’Histoire, la musique, la pensée et l’autobiographie. Dans un premier temps, nous abordons la défaillance langagière. La langue est acquise et cette acquisition nous soumet à une forme de domination sociale. La littérature quignardienne est vouée à désamorcer ce lien grâce au travail de l’auteur qui écrit en lisant. Il en résulte une œuvre qui détient un appareil intertextuel complexe et une écriture à la fois récapitulative et fragmentaire que l’étude des noms, des contes et des rêves met en lumière. Dans un deuxième temps, nous étudions la défaillance sonore. Il s’agit d’analyser l’expérience de la musique en tant que négativité, son rôle dans le milieu concentrationnaire, sa place à l’ère de la reproduction technique, son rapport au silence, à l’indicible et à la mort. Pour finir, nous examinons les raisons de l’hermétisme de cette œuvre et de son obscurité, ainsi que les difficultés qui s’en dégagent. Œuvre qui inclut son propre cheminement herméneutique, nous interrogeons à la fois la place du critique littéraire qu’elle invente et la place du sujet dans le cadre du renouvellement des écritures de soi
First observation of the decay Bs0→K*0K*0
No full textThe first observation of the decay B0s→K∗0K∗0 is reported using 35 pb−1 of data collected by LHCb in proton–proton collisions at a centre-of-mass energy of 7 TeV. A total of 49.8±7.5 B0s→(K+π−)(K−π+) events are observed within ±50 MeV/c2 of the B0s mass and 746 MeV/c2 < mKπ < 1046 MeV/c2, mostly coming from a resonant B0s→K∗0K∗0 signal. The branching fraction and the CP-averaged K∗0 longitudinal polarization fraction are measured to be B(B0s→K∗0K∗0)=(2.81±0.46(stat.)±0.45(syst.)±0.34(fs/ fd))×10−5 and fL =0.31±0.12(stat.)±0.04(syst.)
Globalization, Social Movements, and the Construction of Europe: The Example of the European Parliament Elections in France, CES Working Paper, no. 74, August 2000
No full textThough social scientists have lately devoted themselves to the study of globalization (Waters 1995; Hirst and Thompson 1999), most of these studies have concentrated on its economic and social consequences. Globalization is often seen as a fundamentally unjust process that causes confusion and destroys more than it creates. In many areas, the substantive implications of globalization are left untouched. In this paper, I examine the link between regional integration in Western Europe and the transformation of domestic politics through the example of the European Parliament elections. I argue that globalization through European integration is having a significant impact on French domestic politics. More precisely, the elections to the European Parliament, a supranational political institution, have contributed to the political mobilization of traditionally voiceless groups such as the unemployed and to the introduction into public discussion of new issues tied to Europe, transforming political culture and the relationship between national politics and multinational bargaining (Keohane and Hoffmann 1990, 295). Not only has European political integration provided marginal groups in France with an access to national politics through European Parliament elections, it has also supplied the government and the presidency with new resources, connecting them to trans-European circles and networks that are developing their own political culture. The success of neoliberal economic doctrines in the European Union may have in part to do with these networks. National ministers spend half their time wrestling with European affairs in the Council of Ministers of the European Union and in transnational party structures, developing a common culture and outlook on politics and economics. The main ingredients for this Weltanschauung are well known: electoral cycles should not interfere with economic policy and unemployment figures should not have priority over other monetary indices in the evaluation of economic and political success
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