Hamiltonian Forging of a Thermofield Double

International audienceWe address the variational preparation of Gibbs states as the ground state of a suitably engineered Hamiltonian acting on the doubled Hilbert space. The construction is exact for quadratic fermionic Hamiltonians and gives excellent approximations up to fairly high quartic deformations. We provide a variational circuit whose optimization returns the unitary diagonalizing operator, thus giving access to the whole spectrum. The problem naturally implements the entanglement forging ansatz, allowing the computation of Thermofield Doubles with a higher number of qubits than in competing frameworks

Comparing Compressed and Full-modeling Analyses with FOLPS: Implications for DESI 2024 and beyond

International audienceThe Dark Energy Spectroscopic Instrument (DESI) will provide unprecedented information about the large-scale structure of our Universe. In this work, we study the robustness of the theoretical modelling of the power spectrum of FOLPS, a novel effective field theory-based package for evaluating the redshift space power spectrum in the presence of massive neutrinos. We perform this validation by fitting the AbacusSummit high-accuracy $N$-body simulations for Luminous Red Galaxies, Emission Line Galaxies and Quasar tracers, calibrated to describe DESI observations. We quantify the potential systematic error budget of FOLPS, finding that the modelling errors are fully sub-dominant for the DESI statistical precision within the studied range of scales. Additionally, we study two complementary approaches to fit and analyse the power spectrum data, one based on direct Full-Modelling fits and the other on the ShapeFit compression variables, both resulting in very good agreement in precision and accuracy. In each of these approaches, we study a set of potential systematic errors induced by several assumptions, such as the choice of template cosmology, the effect of prior choice in the nuisance parameters of the model, or the range of scales used in the analysis. Furthermore, we show how opening up the parameter space beyond the vanilla $\Lambda$CDM model affects the DESI observables. These studies include the addition of massive neutrinos, spatial curvature, and dark energy equation of state. We also examine how relaxing the usual Cosmic Microwave Background and Big Bang Nucleosynthesis priors on the primordial spectral index and the baryonic matter abundance, respectively, impacts the inference on the rest of the parameters of interest. This paper pathways towards performing a robust and reliable analysis of the shape of the power spectrum of DESI galaxy and quasar clustering using FOLPS

Emerging Jordan blocks in the two-dimensional Potts and loop models at generic QQ

International audienceIt was recently suggested -- based on general self-consistency arguments as well as results from the bootstrap (arXiv:2005.07708, arXiv:2007.11539, arXiv:2007.04190) -- that the CFT describing the $Q$-state Potts model is logarithmic for generic values of $Q$, with rank-two Jordan blocks for $L_0$ and ${\mkern 1.5mu\overline{\mkern-1.5mu L\mkern-1.5mu}\mkern 1.5mu}_0$ in many sectors of the theory. This is despite the well-known fact that the lattice transfer matrix (or Hamiltonian) is diagonalizable in (arbitrary) finite size. While the emergence of Jordan blocks only in the limit $L\to\infty$ is perfectly possible conceptually, diagonalizability in finite size makes the measurement of logarithmic couplings (whose values are analytically predicted in arXiv:2007.11539, arXiv:2007.04190) very challenging. This problem is solved in the present paper (which can be considered a companion to arXiv:2007.11539), and the conjectured logarithmic structure of the CFT confirmed in detail by the study of the lattice model and associated "emerging Jordan blocks.

Vers une intégration des dosages de microARNs en pratique courante ? enjeux, preuves et freins

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No Robust Sign of Human Influence in the Unprecedented Atmospheric Circulation of Summer 2018 Over Northern Europe

International audienceThe summer of 2018 was characterized by prolonged heatwaves over Northern Europe, associated with persistent atmospheric blocking, and an unusually northward jet stream location over Scandinavia. Whilst event attribution studies tend to focus on the change in probability or magnitude of the extreme temperatures themselves, we provide context to these studies by examining whether there are human induced trends in the atmospheric circulation that might affect the likelihood of similar extreme circulation patterns and associated heat waves occurring in the future. We examine trends and variability in summer jet latitude, blocking frequency and overall circulation pattern over the Scandinavian sector in a variety of reanalyses and climate model ensembles. Both the number of blocked days, and the average jet location for summer 2018 were unprecedented in the reanalyses, and rare in climate model simulations. We found no robust evidence of past or future externally forced changes in summer blocking frequency over Scandinavia in model simulations, whilst trends in circulation analogs were also largely insignificant. Trends in jet latitude were dependent on the time period examined, models included and other analysis choices. Overall, we found no robust evidence for systematic trends in average or extreme years toward Summer 2018-like conditions for any of the three indices, nor in the frequency of co-occurring extreme northward jet latitude and high blocking frequency. We conclude that Summer 2018s circulation can likely be explained by internal atmospheric variability.Plain Language Summary Northern Europe experienced prolonged heatwaves during the summer of 2018. These were associated with an unusually far north jet-stream location and persistent atmospheric blocking over Scandinavia-(i.e., high atmospheric pressure which persists for days to weeks, blocking the passage of other weather systems and contributing to the buildup of heat). Studies on heatwaves commonly seek to quantify how the probability or severity of the hot temperatures has changed due to human-induced climate change. However, it is also important to examine whether the likelihood of the atmospheric circulation patterns leading to such heatwaves has changed, since this may affect how often they occur in the future. We look for trends in summer jet stream location and blocking frequency over Scandinavia, as well as in the number of days with a similar overall circulation pattern to summer 2018 over Europe. We use a combination of climate model simulations and observational data sets (reanalyses). We find that Summer 2018 had the furthest north jet stream location and most blocked days over Scandinavia ever seen since the reanalysis records began in 1948. However, we found no convincing evidence for human-induced trends toward an increased likelihood of such a circulation pattern occurring.</div

Author Correction: Record sea surface temperature jump in 2023–2024 unlikely but not unexpected

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Internal wave energetics and interactions with mesoscale structures in the Sicily Channel area

International audienceThe Sicily Channel plays a crucial role in the general circulation of the Mediterranean Sea. However, the internal wave dynamics is still sparsely characterized in this area which is a hotspot for internal tides. Here, we benefit from a high-resolution model of the Mediterranean Sea with and without tidal forcings to study the synoptic internal wave dynamics in the Sicily Channel area as well as their interactions with the (sub)mesoscale field. We found strong semi-diurnal internal tide generation in the Sicily Channel and the Messina Strait. Diurnal internal tides are generated in the Sicily Channel, Pelagie Islands and the Malta Plateau, and are bottom-trapped because of their sub-inertial frequency. In contrast near-inertial waves are mainly generated in winter in the Tyrrhenian Sea and the northern Ionian Sea. We show that the geometry of the Sicily Channel prevents near-inertial wave to propagate through it. Near-inertial waves are trapped in anticyclonic eddies. In summer, we show that diurnal-inertial internal waves generated by the intense thermal breeze near coastal areas are trapped in anticyclonic eddies with an effective inertial frequency close to the diurnal frequency even far from 30°N of latitude. Implications for turbulence and mixing are discussed. We present indirect evidence of an enhanced forward energy cascade in the presence of tidal motions. Future work will focus on the impact of tidal motions on the energy cascade using a nested non-hydrostatic numerical simulation

Demonstration of Efficient Radon Removal by Silver-Zeolite in a Dark Matter Detector

International audienceWe present the performance of an efficient radon trap using silver-zeolite Ag-ETS-10, measured with a spherical proportional counter filled with an argon/methane mixture. Our study compares the radon reduction capabilities of silver-zeolite and the widely used activated charcoal, both at room temperature. We demonstrate that silver-zeolite significantly outperforms activated charcoal by three orders of magnitude in radon capture. Given that radon is a major background contaminant in rare event searches, our findings highlight silver-zeolite as a highly promising adsorbent, offering compelling operational advantages for both current and future dark matter and neutrino physics experiments. Additionally, this holds great promise for developing future radon reduction systems in underground laboratories in order to increase their supporting capabilities for ton-scale experiments

Conformational dynamics of a multienzyme complex in anaerobic carbon fixation

International audienceIn the ancient microbial Wood-Ljungdahl pathway, carbon dioxide (CO 2 ) is fixed in a multistep process that ends with acetyl–coenzyme A (acetyl-CoA) synthesis at the bifunctional carbon monoxide dehydrogenase/acetyl-CoA synthase complex (CODH/ACS). In this work, we present structural snapshots of the CODH/ACS from the gas-converting acetogen Clostridium autoethanogenum , characterizing the molecular choreography of the overall reaction, including electron transfer to the CODH for CO 2 reduction, methyl transfer from the corrinoid iron-sulfur protein (CoFeSP) partner to the ACS active site, and acetyl-CoA production. Unlike CODH, the multidomain ACS undergoes large conformational changes to form an internal connection to the CODH active site, accommodate the CoFeSP for methyl transfer, and protect the reaction intermediates. Altogether, the structures allow us to draw a detailed reaction mechanism of this enzyme, which is crucial for CO 2 fixation in anaerobic organisms

Supporting Data for “Revealed Preferential Short-Range Anion Ordering in Disordered RbM₂O₅F (M = Nb, Ta) Pyrochlore-Type Oxyfluorides”

International audienceThis is the Supporting Dataset for the manuscript “Revealed Preferential Short-Range Anion Ordering in Disordered RbM2O5F (M = Nb, Ta) Pyrochlore-Type Oxyfluorides”. DOI: https://doi.org/10.1021/acs.inorgchem.5c00615The dataset comprises the following sections:Powder X-ray diffraction data. (directory)High-field solid-state nuclear magnetic resonance spectroscopy data. (directory)Steps for building and generating structural configurations from the unit cell of RbNb2O5F . (directory)First principle calculations data. (directory)Python scripts used to simulate the theoretical NMR spectra. (directory)Python scripts and raw numerical data for all figures included in the main manuscript and the Supporting Information. (directory)</p