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Open Data from LIGO, Virgo, and KAGRA through the First Part of the Fourth Observing Run
No full textInternational audienceLIGO, Virgo, and KAGRA form a network of gravitational-wave observatories. Data and analysis results from this network are made publicly available through the Gravitational Wave Open Science Center. This paper describes open data from this network, including the addition of data from the first part of the fourth observing run (O4a) and selected periods from the preceding engineering run, collected from May 2023 to January 2024. The public data set includes calibrated strain time series for each instrument, data from additional channels used for noise subtraction and detector characterization, and analysis data products from version 4.0 of the Gravitational-Wave Transient Catalog
Observation of emergent scaling of spin–charge correlations at the onset of the pseudogap
No full textInternational audienceIn strongly correlated materials, interacting electrons are entangled and form collective quantum states, resulting in rich low-temperature phase diagrams. Notable examples include cuprate superconductors, in which superconductivity emerges at low doping out of an unusual “pseudogap” metallic state above the critical temperature. The Fermi–Hubbard model, describing a wide range of phenomena associated with strong electron correlations, still offers major computational challenges despite its simple formulation. In this context, ultracold atoms quantum simulators have provided invaluable insights into the microscopic nature of correlated quantum states. Here, we use a quantum gas microscope Fermi–Hubbard simulator to explore a wide range of dopings and temperatures in a regime where a pseudogap is known to develop. By measuring multipoint correlation functions up to fifth order, we uncover a universal scaling behavior in magnetic and higher-order spin–charge correlations characterized by a doping-dependent temperature scale. Accurate comparisons with determinant Quantum Monte Carlo and Minimally Entangled Typical Thermal States simulations confirm that this temperature scale is comparable to the pseudogap temperature T ∗ . Our quantitative findings reveal a qualitative behavior of magnetic properties and spin–charge correlations in an emergent pseudogap and pave the way toward the exploration of charge pairing and collective phenomena expected at lower temperatures
Superfluid fraction in an interacting spatially modulated Bose-Einstein condensate
No full textAt zero temperature, a Galilean-invariant Bose fluid is expected to be fully superfluid. Here we investigate theoretically and experimentally the quenching of the superfluid density of a dilute Bose-Einstein condensate due to the breaking of translational (and thus Galilean) invariance by an external 1D periodic potential. Both Leggett's bound fixed by the knowledge of the total density and the anisotropy of the sound velocity provide a consistent determination of the superfluid fraction. The use of a large-period lattice emphasizes the important role of two-body interactions on superfluidity
Techniques et économies de la Méditerranée antique: [résumé des cours et travaux : 2021-2022]
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Histoire des pouvoirs en Europe occidentale, XIIIᵉ-XVIᵉ siècle: [résumé des cours et travaux : 2021-2022]
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L’invention de l’Europe par les langues et les cultures (chaire annuelle 2021-2022): [résumé des cours et travaux : 2021-2022]
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Biodiversité et écosystèmes (chaire annuelle 2021-2022): [résumé des cours et travaux : 2021-2022]
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On the design and implementation of Modular Explicits
No full textInternational audienceWe present and discuss the design and implementation of modular explicits, an extension of OCaml first-class modules with module-dependent functions, i.e., functions taking first-class modules as arguments. We show some difficulties with the present use of first-class modules and how modular explicits solve them in a simpler, more direct way. Modular explicits are fully compatible with, and can be presented as an extension of first-class modules, which can be precisely formalized by elaboration of OCaml modules and mode-dependent functions into F ω . Interestingly, type inference for modular explicits reuses the mechanism designed to ensure principal types in the presence of semi-explicit first-class polymorphism, already used in OCaml for the typechecking of polymorphic methods and its recent extension with polymorphic parameters. Modular explicits are meant to be the underlying language in which modular implicits, i.e., module arguments left implicit from their signatures, should be elaborated.<