The DUNE Science Program

International audienceThe international collaboration designing and constructing the Deep Underground Neutrino Experiment (DUNE) at the Long-Baseline Neutrino Facility (LBNF) has developed a two-phase strategy for the implementation of this leading-edge, large-scale science project. The 2023 report of the US Particle Physics Project Prioritization Panel (P5) reaffirmed this vision and strongly endorsed DUNE Phase I and Phase II, as did the previous European Strategy for Particle Physics. The construction of DUNE Phase I is well underway. DUNE Phase II consists of a third and fourth far detector module, an upgraded near detector complex, and an enhanced > 2 MW beam. The fourth FD module is conceived as a 'Module of Opportunity', aimed at supporting the core DUNE science program while also expanding the physics opportunities with more advanced technologies. The DUNE collaboration is submitting four main contributions to the 2026 Update of the European Strategy for Particle Physics process. This submission to the 'Neutrinos and cosmic messengers', 'BSM physics' and 'Dark matter and dark sector' streams focuses on the physics program of DUNE. Additional inputs related to DUNE detector technologies and R&D, DUNE software and computing, and European contributions to Fermilab accelerator upgrades and facilities for the DUNE experiment, are also being submitted to other streams

Co-occurrence drives horizontal gene transfer among marine prokaryotes

Understanding the drivers of horizontal gene transfer (HGT) is a key question in microbial evolution. While co-occurring taxa have long been appreciated to undergo HGT more often, this association is confounded with other factors, most notably their phylogenetic distance.To disentangle these factors, we analyzed 15,339 isolate and metagenome-assembled marine genomes. We identified HGT events across these genomes, and identified enrichments for functions previously shown to be prone to HGT. By mapping metagenomic reads from 1,862 ocean samples to these genomes, we also identified co-occurrence patterns and environmental associations. Although we observed an expected negative association between phylogenetic distance and HGT rates, we only detected the association between cooccurrence and phylogenetic distance when restricted to closely related taxa. This observation refines the previously reported trend to closely related taxa, rather than a consistent pattern across all taxonomic levels, at least within marine environments. In addition, we identified a significant association between co-occurrence and HGT, which remains even after controlling for phylogenetic distance and measured environmental variables. Overall, our findings demonstrate the significant influence of ecological associations in shaping marine bacterial evolution through HGT.</p

Full-Shape analysis of the power spectrum and bispectrum of DESI DR1 LRG and QSO samples

International audienceWe present the first joint analysis of the power spectrum and bispectrum using the Data Release 1 (DR1) of the Dark Energy Spectroscopic Instrument (DESI), focusing on Luminous Red Galaxies (LRGs) and quasars (QSOs) across a redshift range of $0.4\leq z\leq2.1$. By combining the two- and three-point statistics, we are able to partially break the degeneracy between the logarithmic growth rate, $f(z)$, and the amplitude of dark matter fluctuations, $\sigma_\textrm{s8}(z)$, which cannot be measured separately in analyses that only involve the power spectrum. In comparison with the (fiducial) Planck $\Lambda$CDM cosmology we obtain $f/f^\textrm{fid}=\{0.888_{-0.089}^{+0.186},0.977_{-0.220}^{+0.182},1.030_{-0.085}^{+0.368}\}$, $\sigma_{s8}/\sigma^\textrm{fid}_\textrm{s8}=\{1.224_{-0.133}^{+0.091},1.071_{-0.163}^{+0.278},1.000_{-0.223}^{+0.088}\}$ respectively for the three LRG redshift bins, corresponding to a cumulative 10.1% constraint on $f$, and of 8.4% on $\sigma_\textrm{s8}$, including the systematic error budget. The cumulative constraints for the ShapeFit compressed parameters from our joint power spectrum-bispectrum analysis are respectively $\sigma_{\alpha_\textrm{iso}}=0.9\%$ (9% improvement with respect to our power spectrum-only analysis); $\sigma_{\alpha_\textrm{AP}}=2.3\%$ (no improvement with respect to power spectrum-only analysis, which is expected given that the bispectrum monopole has no significant anisotropic signal); $\sigma_{f\sigma_\textrm{s8}}=5.1\%$ (9% improvement); $\sigma_{m+n}=2.3\%$ (11% improvement). These results are fully consistent with the main DESI power spectrum analysis, demonstrating the robustness of the DESI cosmological constraints, and compatible with Planck $\Lambda$CDM cosmology

JENA Computing Initiative WP2 Report: Software and Heterogeneous Architectures

International audienceThe scientific communities of nuclear, particle, and astroparticle physics are continuing to advance and are facing unprecedented software challenges due to growing data volumes, complex computing needs, and environmental considerations. As new experiments emerge, software and computing needs must be recognised and integrated early in design phases. This document synthesises insights from ECFA, NuPECC and APPEC, representing particle physics, nuclear physics, and astroparticle physics, and presents collaborative strategies for improving software, computing frameworks, infrastructure, and career development within these fields

Efficient interaction-based offline runtime verification of distributed systems with lifeline removal

International audienceRuntime Verification (RV) refers to a family of techniques in which system executions are observed and confronted to formal specifications, with the aim of identifying faults. In offline RV, observation and verification are done in two separate and successive steps. In this paper, we define an approach to offline RV of Distributed Systems (DS) against interactions. Interactions are formal models describing communications within a DS. A DS is composed of subsystems deployed on different machines and interacting via message passing to achieve common goals. Therefore, observing executions of a DS entails logging a collection of local execution traces, one for each subsystem, collected on its host machine. We call multi-trace such observational artifacts. A major challenge in analyzing multi-traces is that there are no practical means to synchronize the ends of observations of all the local traces. We address this via an operation called lifeline removal, which we apply on-the-fly to the specification during the verification of a multi-trace once a local trace has been entirely analyzed. This operation removes from the interaction the specification of actions occurring on the subsystem that is no longer observed. This may allow further execution of the specification by removing potential deadlock. We prove the correctness of the resulting RV algorithm and introduce two optimization techniques, which we also prove correct. We implement a Partial Order Reduction (POR) technique by selecting a one-unambiguous action (as a unique first step to a linearization) whose existence is determined via the lifeline removal operator. Additionally, Local Analyses (LOC), i.e., the verification of local traces, can be leveraged during the global multi-trace analysis to prove failure more quickly. Experiments illustrate the application of our RV approach and the benefits of our optimizations

Transcriptomic response of the picoalga Pelagomonas calceolata to nitrogen availability: new insights into cyanate lyase function

International audienceAbstract. Cyanate (OCN − ) is an organic nitrogen compound found in aquatic environments potentially involved in phytoplankton growth. Given the prevalence and activity of cyanate lyase genes in eukaryotic microalgae, cyanate has been suggested as an alternative source of nitrogen in the environment. However, the conditions under which cyanate lyase is expressed and the actual capacity of microalgae to assimilate cyanate remain largely underexplored. Here, we studied the nitrogen metabolism in the cosmopolitan open-ocean picoalga Pelagomonas calceolata (Pelagophyceae and Stramenopiles) in environmental metatranscriptomes and transcriptomes from culture experiments under different nitrogen sources and concentrations. We observed that cyanate lyase is upregulated in nitrate-poor oceanic regions, suggesting that cyanate is an important molecule contributing to the persistence of P. calceolata in oligotrophic environments. Non-axenic cultures of P. calceolata were capable of growing on various nitrogen sources, including nitrate, urea, and cyanate, but not ammonium. RNA sequencing of these cultures revealed that cyanate lyase was downregulated in the presence of cyanate, indicating that this gene is not involved in the catabolism of extracellular cyanate to ammonia. Based on environmental data sets and laboratory experiments, we propose that cyanate lyase is important in nitrate-poor environments to generate ammonia from cyanate produced by endogenous nitrogenous compound recycling rather than being used to metabolize imported extracellular cyanate as an alternative nitrogen source.Importance. Vast oceanic regions are nutrient-poor, yet several microalgae thrive in these environments. While various acclimation strategies to these conditions have been discovered in a limited number of model microalgae, many important lineages remain understudied. Investigating nitrogen metabolism across different microalga lineages is crucial for understanding ecosystem functioning in low-nitrate areas, especially in the context of global ocean warming. This study describes the nitrogen metabolism of Pelagomonas calceolata , an abundant ochrophyte in temperate and tropical oceans. By utilizing both global scale in situ metatranscriptomes and laboratory-based transcriptomics, we uncover how P. calceolata adapts to low-nitrate conditions. Our findings reveal that P. calceolata can metabolize various nitrogenous compounds and relies on cyanate lyase to recycle endogenous nitrogen in low-nitrate conditions. This result paves the way for future investigations into the significance of cyanate metabolism within oceanic trophic webs

Cohérence quantique, mélange intercanal et dissipation dans les canaux de bords des effets Hall quantiques fractionnaires et entiers

This thesis focuses on the study of quantum decoherence, inter-channel tunneling, and dissipation in the integer and fractional quantum Hall states, using the platform of two-dimensional gases—notably formed at the interface of the n-doped GaAs/AlGaAs heterostructure used here. Quantum decoherence refers to the loss of quantum behavior of a studied system, which can be induced by coupling to the external environment. Quantum computing relies on the principle of quantum coherence, and understanding the mechanisms leading to decoherence would enhance our grasp of quantum computing theory, and quantum mechanics in general. During this thesis, the initial focus was on understanding the mechanisms by which decoherence occurs in two different situations: in the integer quantum Hall effect and in the fractional quantum Hall effect (2/3). Then, in the final part, the research was dedicated to the fabrication of a single-electron detector, the last missing link in the chain needed to perform operations with flying electronic qubits — qubits not defined by a two-level energy system, but by a system with two spatial positions. Firstly, in the case of the integer quantum Hall effect, the edge channels all propagate in the same direction, determined in this case by the direction of the magnetic field applied perpendicularly to the sample, and can have opposite spins, which does not favor inter-channel tunneling. However, the n-doped GaAs/AlGaAs heterostructure, due to symmetry breaking in the direction perpendicular to the 2D gas, possesses spin-orbit coupling via the Bychkov-Rashba effect. Thus, the spin can be flipped, which is conducive to elastic inter-channel tunneling. Furthermore, the presence of gates in the middle of the sample, such as the quantum point contact—which is associated with an electric field locally depleting the 2D gas beneath its surface—causes a sudden change in direction for the electrons, potentially leading to tunneling at the point of spatial curvature change. The presence of tunneling is then highlighted here by modeling the partition noise produced by a tunneling point and its measurement. Secondly, in the case of the fractional quantum Hall effect at 2/3, the edge channels are counter-propagating, favoring inter-channel tunneling, which occurs frequently, inelastically, and randomly. A very simple model of this effect can be reproduced by introducing "black boxes", the Landauer reservoirs—or equivalently, energy-preserving reservoirs—where inelastic tunneling is allowed within. The model converges to the historical KFP model when enough reservoirs are introduced. When a quantum point contact is introduced, a conductance plateau at 0.5e²/h is predicted and measured during the experiments conducted in this thesis. Additionally, the presence of dissipation is shown and validated. However, Hong-Ou-Mandel type interferometry experiments reveal a non-zero visibility, indicating that the dissipation mechanism does not cause a total loss of coherence. Finally, in addition to the previous experiments, a single-electron detector was conceived to preserve quantum coherence when measuring a flying qubit, allowing it to be reused for subsequent operations, thus paving the way for quantum computing in two-dimensional electron gases under the quantum Hall effect regime. While the detector has been realized and can detect up to several hundred electrons, the technical optimizations needed to detect a single electron could not be completed before the end of the allotted time for this thesis.Cette thèse porte sur l'étude de la décoherence quantique, du tunneling intercanal et de la dissipation dans les états entiers et fractionnaires de l'effet Hall quantique, en utilisant la plateforme des gaz bidimensionnels à deux dimensions — qui se forme notamment à l'interface de l'hétérostructure dopée n GaAs/AlGaAs, utilisée ici. La décohérence quantique traduit la perte du comportement quantique d'un système étudié, ce qui peut notamment être induit par couplage à l'environnement extérieur. L'informatique quantique repose sur le principe de cohérence quantique, et la compréhension des mécanismes donnant lieu à la décohérence permettrait de mieux saisir la théorie de l'informatique quantique, voire la mécanique quantique de manière générale. Lors de cette thèse, il a été question dans un premier temps de comprendre par quels mécanismes la décoherence a lieu, dans deux situations différentes : dans l'effet Hall quantique entier et dans l'effet Hall quantique fractionnaire (2/3). Puis, dans un dernier temps, la recherche a été dévouée à la fabrication d'un détecteur à électron unique, le dernier maillon de la chaîne manquant pour pouvoir réaliser des opérations avec les qubits volants électroniques — des qubits non pas définis par un système à deux niveaux d'énergie, mais par un système à deux positions spatiales.Premièrement, dans le cas de l'effet Hall quantique entier, les canaux de bords se propagent tous dans la même direction, fixée dans le cas présent par le sens du champ magnétique appliqué perpendiculairement à l'échantillon, et peuvent être de spin opposés, ce qui ne favorise pas le tunneling intercanal. Cependant, l'hétérostructure dopée n GaAs/AlGaAs, par brisure de symétrie dans la direction perpendiculaire au gaz 2D, possède un couplage spin-orbite par effet Bychkov-Rashba. Ainsi, le spin peut être renversé ce qui est propice au tunneling intercanal élastique. Par ailleurs, la présence de grilles au milieu de l'échantillon, comme le point de contact quantique — qui est associé à un champ électrique déplétant localement le gaz 2D sous sa surface — provoque un soudain changement de direction chez les électrons, et peut donc ainsi provoquer du tunneling au point de changement de courbure spatiale. La présence de tunneling est alors ici mise en évidence par une modélisation du bruit de partitionnement produit par un point de tunneling, et sa mesure.Secondement, dans le cas de l'effet Hall quantique fractionnaire à 2/3, les canaux de bords sont contre-propageants, favorisant le tunneling intercanal, qui se produit alors de manière fréquente, inélastique et aléatoire. Un modèle très simple de cet effet peut être reproduit en introduisant des “boîtes noires”, les réservoirs de Landauer — ou de manière équivalente, des réservoirs à conservation d'énergie — où le tunneling inélastique est autorisé en son sein. Le modèle converge vers le modèle historique de KFP lorsque suffisamment de réservoirs sont introduits. Et lorsqu'un point de contact quantique est introduit, un plateau de conductance à 0.5e²/h est prédit, et mesuré lors des expériences effectuées lors de cette thèse. Par ailleurs, la présence de dissipation est montrée et validée. Mais des expériences d'interférométrie de type Hong-Ou-Mandel révèlent une visibilité non nulle, le mécanisme de dissipation ne provoque pas de perte de cohérence quasi-totale. Finalement, en plus des expériences précédentes, il a été pensé un détecteur à électron unique préservant la cohérence quantique lors de la mesure d'un qubit volant; permettant à celui-ci d'être réutilisé pour des opérations ultérieures, ouvrant ainsi la voie à l'informatique quantique dans les gaz bidimensionnels d'électrons sous le régime d'effet Hall quantique. Si le détecteur a été réalisé, et peut détecter jusqu'à plusieurs centaines d'électrons, les optimisations techniques lui permettant de détecter l'électron unique n'ont pas pu être terminées avant la fin du temps imparti pour cette thèse

Document complémentaire à l'article "Étude de comparaisons de procédures de sélection de variables en régression linéaire gaussienne de grande dimension".

51 pages, 50 figuresDonnées supplémentaires pour un preprintThis supplementary file is an appendix of the work entitled "Comparison study of variable selection procedures in high-dimensional Gaussian linear regression". This file contains additional graphics summarizing the behavior of the variable selection methods applied on different datasets considered in the main document

Fixed point method for PET reconstruction with plug-and-play regularization

Deep learning has shown great promise for improving medical image reconstruction, often surpassing traditional model-based iterative methods. However, concerns remain about the stability and robustness of these approaches, particularly when trained on limited data. The Plug-and-Play framework offers a promising solution, showing that a convergent and robust reconstruction can be ensured, provided conditions on the plugged network. Yet, it has been underexplored in PET reconstruction.This paper introduces a convergent PnP algorithm for low-count PET reconstruction, leveraging the Douglas-Rachford splitting method and various networks trained on the fixed point conditions. We evaluate bias-standard deviation tradeoffs across multiple regions including an unseen pathological case and compared to model-based iterative reconstruction, post-reconstruction processing, and PnP with a Gaussian denoiser. Our findings emphasize the importance of how convergence conditions are imposed on the PnP networks. While spectral normalization underperformed, our deep equilibrium model remained competitive with convolutional architectures and generalized better on our unseen pathology. Our method achieved lower bias than post-reconstruction processing and reduced standard deviation at matched bias compared to model-based iterative reconstruction. Our results demonstrate PnP's potential to improve image quality and quantification accuracy in PET reconstruction

Bias dependent band alignment in Ga2O3 ferroelectric interface by operando HAXPES

International audienceWe present a fundamental study of the band alignment at the interface of HfZrO4 (HZO) with Ge-doped Ga2O3. Ge is an alternative n-type dopant for the wide band gap Ga2O3 due to its shallow donor level and favorable MBE growth conditions. In the perspective of using the ferroelectric polarization of hafnia based oxides, we have used a stack of HZO on highly Ge doped Ga2O3, the latter providing high carrier density. Electrical contacts were ensured by a TiN top electrode deposited on the HZO and an Au pad on the Ge:Ga2O3. The band alignment was measured by carrying out hard X-ray photoelectron spectroscopy (HAXPES) with in situ bias application across the HZO and following the evolution of both HZO and Ga2O3 energy level. Complementary high-resolution transmission electron microscopy (HRTEM) provided structural confirmation of the polar orthorhombic phase however electrical characterization showed that charge injection and trapping at the interface prevents stabilizing the ferroelectric polarization in HZO. The band alignment in the presence of a leaky HZO layer is therefore dominated by the bias induced band skewing