Portail HAL du Collège de France
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Garden Culture, Water, and Spiritual Guidance: Shifting Trends from Byzantine Constantinople to Istanbul
No full textInternational audienc
MMC Array to Study X-ray Transitions in Muonic Atoms
No full textInternational audienceThe QUARTET collaboration aims to significantly improve the precision of the absolute nuclear charge radii of light nuclei from Li to Ne by using an array of metallic magnetic calorimeters to perform high-precision X-ray spectroscopy of low-lying states in muonic atoms. A proof-of-principle measurement with lithium, beryllium and boron is planned for fall 2023 at the Paul Scherrer Institute. We discuss the performance achieved with the maXs-30 detector module to be used. To place the detector close to the target chamber where the muon beam will impact the material under study, we have developed a new dilution refrigerator sidearm. We further discuss the expected efficiency given the transparency of the X-ray windows and the quantum efficiency of the detector. The expected muonic X-ray rate combined with the high resolving power and detection efficiency of the detector suggest that QUARTET will be able to study the de-excitation of light muonic atoms at an unprecedented level, increasing the relative energy resolution by up to a factor of 20 compared to conventional detector techniques
L'Appendice à la Consécration de l'Arcane selon le Khandro Nyingthik (mKha’ ‘gro snying thig gsang dbang gi lhan thabs)
No full textThe BMS group in D = 6 spacetime dimensions
No full textInternational audienceThe asymptotic structure of gravity in D = 6 spacetime dimensions is described at spatial infinity in the asymptotically flat context through Hamiltonian (ADM) methods. Special focus is given on the Bondi–Metzner–Sachs (BMS) supertranslation subgroup. It is known from previous studies that the BMS group contains more supertranslations as one goes from D = 4 to D = 5. Indeed, while the supertranslations are described by one single function of the angles in D = 4, four such functions are neeeded in D = 5. We consider the case D = 6 with the aim of determining whether the number of supertranslations keeps increasing with the dimension or remains equal to the number found in D = 5. We show that even though there is apparent room for more supertranslations, their number remains equal to the D = 5 value (four): the potentially new supertranslations turn out to define proper gauge transformations corresponding to a redundancy in the description of the system. Critical in the analysis are the boundary conditions chosen to yield a well-defined canonical formalism. Given the computational (but not conceptual) complexity as one increases the dimension, we explicitly discuss the linearized theory and argue that asymptotically, this analysis provides the correct picture. We conclude by considering higher spacetime dimensions where we indicate that the number of physically relevant supertranslations remains equal to four independently of the dimension ⩾ 5 . Contribution to Stanley Deser memorial volume ‘Gravity, Strings and Beyond
Adrian Palladino, Inventing Late Antique Reliquaries. Reception, Material History, and Dynamics of Interaction (4th -6th centuries CE), Rome - Brno, Viella - Masaryk University Press (Studia Artium Mediaevalium Brunensia, 12), 2022, 312 p., ISBN 978-88-3313-867-1 (48 €)
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Avigaïl : femme sage, prophétesse ou reine ? Une lecture de 1 Samuel 25
No full textInternational audienceAvigail only plays a significant role in 1 Samuel 25. Who is this mysterious Avigail: a wise woman? a prophetess? or a king’s wife? This paper presents a redactional hypothesis: in the original story, Avigail was a wise woman who intervened to save her threatened home. The Deuteronomistic school emphasizes the kingship of David, but also the sovereignty of YHWH. Avigail takes on the characteristics of a prophetess. Finally, a later version introduces the motif of marriage, making both Avigail and David conspirators
Symmetry: a fundamental resource for quantum coherence and metrology
No full textInternational audienceWe introduce a new paradigm for the preparation of deeply entangled states useful for quantum metrology. We show that when the quantum state is an eigenstate of an operator , observables which are completely off-diagonal with respect to have purely quantum fluctuations, as quantified by the quantum Fisher information, namely . This property holds regardless of the purity of the quantum state, and it implies that off-diagonal fluctuations represent a metrological resource for phase estimation. In particular, for many-body systems such as quantum spin ensembles or bosonic gases, the presence of off-diagonal long-range order (for a spin observable, or for bosonic operators) directly translates into a metrological resource, provided that the system remains in a well-defined symmetry sector. The latter is defined e.g. by one component of the collective spin or by its parity in spin systems; and by a particle-number sector for bosons. Our results establish the optimal use for metrology of arbitrarily non-Gaussian quantum correlations in a large variety of many-body systems
LRGrep : sélection de messages d'erreur pour les analyseurs LR
No full textLR parsers are highly suitable for syntactic analysis of programming languages as they guarantee linear-time recognition and ensure grammatical non-ambiguity. When processing an incorrect input, an LR parser recognizes the correct prefix (common with valid sentences) but does not inherently provide additional context. While this allows an LR parser to pinpoint the position of a syntax error, it does little to explain the issue to users. Consequently, LR parsers have developed a reputation for producing brief and unhelpful error reports. As a consequence, an alternative approach is often preferred when more informative feedback is necessary. This thesis challenges that perception. In an LR parser, the grammar, through the automaton, is available as an object which can be manipulated, for example, to study incorrect sentences and refine the parser's behavior in case of errors. To implement this idea, we propose a declarative language for specifying error messages, complementary to the grammar. We develop tools to recognize these specifications and facilitate their design, and we test the validity of this approach by reproducing or improving syntax error messages for three programming languages: OCaml, Catala, and Elm.Les analyseurs LR sont une technologie de choix pour l'analyse syntaxique des langages de programmation ; notamment, ils garantissent une reconnaissance en temps linéaire et l'absence d'ambiguïté grammaticale. Lorsqu'ils traitent une phrase incorrecte, ces analyseurs reconnaissent le préfixe correct (partagé avec des phrases du langage) mais ne fournissent a priori pas d'autre information. Cela permet de pointer la position d'une erreur syntaxique mais pas d'expliquer le problème à l'utilisateur. Les analyseurs LR ont donc acquis la réputation de produire des rapports d'erreur sommaires ; quand cet aspect est important, une autre approche que LR sera généralement préférée. Cette thèse remet en question cette idée. Dans un analyseur LR, la grammaire, via l'automate, est un objet qui peut être manipulé à part entière, par exemple pour étudier les phrases incorrectes et raffiner le comportement de l'analyseur en cas d'erreur. Pour réaliser cette idée, nous proposons un langage déclaratif de spécification des messages d'erreur, complémentaire à la grammaire. Nous développons des outils pour reconnaître ces spécifications et faciliter leur conception, et nous testons la validité de cette approche en reproduisant ou en améliorant les messages d'erreur syntaxiques pour trois langages de programmation : OCaml, Catala et Elm
New research perspective in the Western Himalayas : French-Nepali Archaeological Mission in Mustang (Nepal)
No full textInternational audienceThe Mustang District, located in north-west Nepal, is historically known as an important NScorridor following the course of the Kali Gandaki River and linking the Tibetan plateau to theIndian plains. Historical sources describing the region are scarce or even non-existent for periodspreceding the 7th century CE. Despite this lack of written sources and the region’s importance forunderstanding the different dynamics influencing regional trading routes and cultural exchanges,very little archaeological research has been carried out in Mustang. This is partly due to accessrestrictions as well as local beliefs, rendering archaeological excavations extremely difficult.Recent investigations in Mustang conducted by Marion Poux over the last 5 years have,however, revealed the vast archaeological richness of the Kali Gandaki Valley. These investigationsresulted in the identification of about 200 archaeological sites, 30 of which have been radiocarbondated. In order to better understand the development of early settlement sites in Upper Mustang, butalso to better characterize some of these newly identified sites, we have decided to develop a newresearch program. This paper will focus on the presentation of this project, and the initial resultsobtained during the 2023 fieldwork campaign. We will also present some of the solutions andmethodologies we have put in place in order to elaborate a more detailed chronological framework,as well as developing a better understanding of cultural interactions between Mustang andneighboring regions