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Nondestructive optomechanical detection scheme for Bose-Einstein condensates
No full textInternational audienceWe present a two-tone heterodyne optical readout scheme to extract unequal-time density correlations along an arbitrary stationary interaction path from a pancake-shaped Bose-Einstein condensate, using a modulated laser probe. Analysing the measurement noise both from imprecision and backaction, we identify the standard quantum limit for the signal-extraction scheme, and examine how a class of two-mode squeezed initial states can be used to push beyond this limit. As an application, we show how the readout scheme can be used for an experimental realisation of acceleration-dependence of quantum-vacuum fluctuations in the system, including the analogue spacetime circular motion Unruh effect
A Lazy, Concurrent Convertibility Checker
No full textInternational audienceConvertibility checking — determining whether two lambda-terms are equal up to reductions — is a crucial component of proof assistants and dependently-typed languages. Practical implementations often use heuristics to quickly conclude that two terms are or are not convertible without reducing them to normal form. However, these heuristics can backfire, triggering huge amounts of unnecessary computation. This paper presents a novel convertibility-checking algorithm that relies crucially on laziness and concurrency} Laziness is used to share computations, while concurrency is used to explore multiple convertibility subproblems in parallel or via fair interleaving. Unlike heuristics-based approaches, our algorithm always finds an easy solution to the convertibility problem, if one exists. The paper presents the algorithm in process calculus style and discusses its mechanized proof of partial correctness, its complexity, and its lightweight experimental evaluation
Early hominins from Morocco basal to the Homo sapiens lineage
No full textInternational audiencePalaeogenetic evidence suggests that the last common ancestor of present-day humans, Neanderthals and Denisovans lived around 765–550 thousand years ago (ka)1. However, both the geographical distribution and the morphology of these ancestral humans remain uncertain. The Homo antecessor fossils from the TD6 layer of Gran Dolina at Atapuerca, Spain, dated between 950 ka and 770 ka (ref. 2), have been proposed as potential candidates for this ancestral population3. However, all securely dated Homo sapiens fossils before 90 ka were found either in Africa or at the gateway to Asia, strongly suggesting an African rather than a Eurasian origin of our species. Here we describe new hominin fossils from the Grotte à Hominidés at Thomas Quarry I (ThI-GH) in Casablanca, Morocco, dated to around 773 ka. These fossils are similar in age to H. antecessor, yet are morphologically distinct, displaying a combination of primitive traits and of derived features reminiscent of later H. sapiens and Eurasian archaic hominins. The ThI-GH hominins provide insights into African populations predating the earliest H. sapiens individuals discovered at Jebel Irhoud in Morocco4 and provide strong evidence for an African lineage ancestral to our species. These fossils offer clues about the last common ancestor shared with Neanderthals and Denisovans
Trivalence and Transparency: a non-dynamic approach to anaphora
No full textThis paper offers a new theory of donkey anaphora that does not include any dynamic component. Even if the approach is not dynamic, it retains a key aspect of the dynamic tradition, namely the view that information states include not just factual information about the world, but also information about discourse referents, e.g., variables. It also makes crucial use of plural assignment functions (sets of standard assignments, cf. van der Berg 1996; Nouwen 2003; Brasoveanu 2008). Unlike dynamic approaches, sentences are evaluated as true or false relative to a pair (w, G), where w is a possible world and G is a plural assignment, with no reference to contexts or information states, and compositional semantics does not refer in any way to context update. In order to predict adequate meanings and felicity conditions, I combine two ingredients that have been used to account for presupposition projection, namely Trivalence (Peters 1979; Beaver and Krahmer 2001) and Schlenker’s Transparency Principle (Schlenker 2007, 2008a). Two ideas play a crucial role in the proposal. First, a sentence such as ‘Shex came’ comes with the presupposition that the variable x is ‘valued’ and denotes an atomic individual, which means that every atomic assignment in G maps x to the same atomic value. Second I adopt Mandelkern’s (2022) witness condition: an existential statement such as ‘Someonex came’ is undefined in (w, G) if it is classically true in w but G does not map x to a witness of the existential statement. Importantly, undefinedness is not equated with Presupposition Failure (e.g., even though ‘Someonex came’ can be undefined, it is in fact never a presupposition failure). Rather, presupposition projection is governed by Schlenker’s Transparency Principle (Schlenker 2007, 2008a): the presupposition ‘x is valued and atomic’ should be redundant in the syntactic position in which ‘Shex came’ occurs. In the end of the paper, I discuss well-known ambiguities with donkey sentences (weak vs. strong, existential vs. universal readings) and show how they can be addressed in my system. The theory is presented here as a non-standard semantics for first-order logic, rather than a fragment of a natural language. Free variables are the counterparts of syntactically unbound pronouns, and existential quantifiers those of singular indefinites
Exploited marine fish distributions in Europe under past climates
No full textSpecies distribution modelling is widely used to assess the responses of exploited marine species to environmental change, as shifts in their spatial distributions directly affect food security and fisheries-dependent socio-economic activities. To date, most studies have focused on forecasting future range shifts under ongoing climate change. In contrast, far fewer studies have examined how past environmental changes shaped the historical distributions of exploited marine fishes, despite the potential of such reconstructions to inform both archaeological research and expectations of future responses. Here, we investigate past spatial changes in the distributions of 17 of the most commonly exploited teleost fish species in Mediterranean and European waters using a species distribution modelling framework. We reconstructed species’ distributions under two contrasted palaeoclimatic periods, the Mid-Holocene (6 ka BP) and the Last Glacial Maximum (LGM; 21 ka BP), spanning markedly different thermal regimes. Hindcast projections were further used to characterize latitudinal patterns of past environment suitability, providing a broad-scale perspective on how climatic variability historically constrained or redistributed suitable environmentsfor exploited species.Our results reveal negligible differences in environmentalsuitability between the Mid-Holocene and present-day conditions for all species, indicating limited large-scale environmental changes during the Holocene. In contrast, the LGM induced pronounced and species-specific reorganizations of suitable environment. Distributional responses were primarily driven by temperature and distance to the coast. Temperate species generally exhibited latitudinal shifts toward lower latitudes, whereas subtropical species showed widespread decreases in predicted suitability and stronger contractions of suitable area. Coastal species experienced major reductions in potential habitat extent, while offshore species were comparatively less affected. By providing spatially explicit environmental baselines, this study contributes to the interpretation of archaeological evidence and offers a long-term reference for discussing contemporary exploitation patterns in relation to past environmental constraints
Ordres de charge et de spin dans le modèle t-U-V-J : une approche de particule esclave de spin 1
No full textStrongly-correlated fermion systems on a lattice have been a subject of intense focus in the field of condensed-matter physics. These systems are notoriously difficult to solve, even with state-of-theart numerical methods, especially in regimes of parameters where degrees of freedom compete or cooperate at similar energy and length scales. Here, we introduce a spin-1 slave-particle technique to approximately treat the t-U -V -J fermionic model at arbitrary electron dopings in a simple manner. This formalism relies on a self-consistent cluster mean-field method, and it couples effective pseudo-spin and pseudo-fermion sectors, representing the original electron charge and spin degrees, respectively. We study the phase diagram of the model under various conditions and report the appearance of charge and spin stripes within this formalism. These stripes are a consequence of the cluster mean-field treatment of the pseudo-particle sectors and have not been detected in previous slave-particle studies.Les systèmes de fermions fortement corrélés sur un réseau ont fait l'objet d'une attention particulière dans le domaine de la physique de la matière condensée. Ces systèmes sont réputés difficiles à résoudre, même avec les méthodes numériques les plus avancées, en particulier dans les régimes de paramètres où les degrés de liberté entrent en concurrence ou coopèrent à des échelles d'énergie et de longueur similaires. Nous présentons ici une technique de particule esclave de spin 1 permettant de traiter de manière simple et approximative le modèle fermionique t-U-V-J à des dopages électroniques arbitraires. Ce formalisme repose sur une méthode de champ moyen de cluster auto-cohérente et couple les secteurs pseudo-spin et pseudo-fermion effectifs, représentant respectivement les degrés de charge et de spin électroniques d'origine. Nous étudions le diagramme de phase du modèle dans diverses conditions et signalons l'apparition de bandes de charge et de spin dans ce formalisme. Ces bandes sont une conséquence du traitement par champ moyen sur cluster des secteurs de pseudo-particules et n'ont pas été détectées dans les études précédentes de particules esclaves
Le conspirationnisme comme outil d’intégration. L’antimaçonnisme catholique dans le débat intellectuel de la seconde moitié de l’ère Meiji (1880-1912)
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GWTC-4.0: Updating the Gravitational-Wave Transient Catalog with Observations from the First Part of the Fourth LIGO-Virgo-KAGRA Observing Run
No full textInternational audienceVersion 4.0 of the Gravitational-Wave Transient Catalog (GWTC-4.0) adds new candidates detected by the LIGO, Virgo, and KAGRA observatories through the first part of the fourth observing run (O4a: 2023 May 24 15:00:00 to 2024 January 16 16:00:00 UTC) and a preceding engineering run. In this new data, we find 128 new compact binary coalescence candidates that are identified by at least one of our search algorithms with a probability of astrophysical origin and that are not vetoed during event validation. We also provide detailed source property measurements for 86 of these that have a false alarm rate < 1 \rm{yr}^{-1}. Based on the inferred component masses, these new candidates are consistent with signals from binary black holes and neutron star-black hole binaries (GW230518_125908 and GW230529_181500). Median inferred component masses of binary black holes in the catalog now range from (GW230627_015337) to (GW231123_135430), while GW231123_135430 was probably produced by the most massive binary observed in the catalog. For the first time we have discovered binary black hole signals with network signal-to-noise ratio exceeding 30, GW230814_230901 and GW231226_01520, enabling high-fidelity studies of the waveforms and astrophysical properties of these systems. Combined with the 90 candidates included in GWTC-3.0, the catalog now contains 218 candidates with and not otherwise vetoed, doubling the size of the catalog and further opening our view of the gravitational-wave Universe
Phylogeny, systematics and evolution of mimicry patterns in Neotropical limenitidine butterflies
No full textDATA AVAILABILITY STATEMENT: The data that support the findings of this study are openly available in the Dryad repository at https://doi.org/10.5061/dryad.7h44j104b (Pàez et al, 2025). Newly generated sequences were deposited in GenBank at https://www.ncbi.nlm.nih.gov and are registered with the following accession numbers: PX243222–PX243274, PX244453–PX244551 (COI); PX114826–PX114854 (EF1a); PX172283–PX172334 (GAPDH); PX172335, PX254824–PX254850 (IDH); PX254786–PX254823 (RpS5); PX207538–PX207552 (ArgKin); PX172259–PX172282 (CAD); PX207522–PX207537 (CycY); PX172235–PX172258 (DDC); PX270910–PX270945 (Exp1); PX172202–PX172234 (Nex9); PX114965–PX115012 (PolII); PX114932–PX114964 (ProSup); PX114890–PX114931 (PSb); PX114855–PX114889 (RpS2); PX207556–PX207592 (UDPG6DH) (see Table S1 for details).International audienceThe Neotropical butterfly genus Adelpha Hübner exhibits remarkable species diversity and striking convergence in wing colour patterns potentially explained by mimicry, making it an exceptional model for exploring trait evolution and its relationship with speciation. To date, unresolved phylogenetic relationships hinder a comprehensive understanding of the evolutionary biology of the genus. Using a novel multi‐marker dataset combining one mitochondrial and 15 nuclear gene fragments, we generate the most comprehensive phylogeny of the genus Adelpha to revisit its systematics and investigate the evolution of mimicry colour patterns. Our dataset encompasses 83 of the 87 known extant species and six Limenitis species that were recently excluded from Adelpha (134 of c . 160 subspecies in total), collectively displaying 14 distinct mimicry patterns. We provide conclusive evidence that corroborates previous work on the polyphyly of Adelpha as historically conceived and describe the genus Adelphina Páez & Willmott n. gen . to stabilise the nomenclature. The comprehensive phylogeny provided in this study lays a solid foundation for future research into the processes driving diversification within these species interacting through mimicry. Ancestral character state reconstruction reveals the gradual evolution of mimicry patterns. The more common mimicry pattern IPHICLUS (forewing with orange subapical spot and white band) is inferred as ancestral, but repeated convergent evolution is also recovered. Evolutionary convergence is also observed for the second most abundant mimicry pattern, COCALA (orange‐white banded). Increased rates of mimicry pattern evolution are also found towards the equator. These results underscore the complexity of mimicry evolution in the Neotropical limenitidines, i.e., Adelpha and Adelphina n. gen. , emphasising the need to explore its interplay with other biotic and abiotic factors
