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Japanese and Chinese Porcelains and the Role of Jesuit Missionaries
No full textInternational audienceThe role of Jesuit missionaries from Europe (predominantly Portugal, Spain and France) to the Imperial Courts of Japan and China in the sixteenth, seventeenth and eighteenth centuries and their influence upon the production and decoration of Arita and Chinese porcelains imported into Europe. The critical revelation of the composition and production processes of Chinese porcelains at Jingdezhen by Father Xavier Dentrecolles in Peking to his superior Father Orry in Paris in the first two decades of the eighteenth century and its impetus on European porcelain manufacture thereafter. The Jesuits and their diplomatic gifts of Limoges, Blois and Paris enamelled metalwares to the Emperor Kangxi and the resultant upsurge in the Chinese polychrome porcelain decoration and trade with Europe in pigments, especially cobalt blue, gold rose and Naples yellow: the rise of famille verte and famille rose decorated porcelains
Cobalt Blues, Smalts
No full textInternational audienceThe cobalt blues, cobalt sources and their mining, European, Middle Eastern and Chinese origins of cobalt blue pigments on porcelains from analytical studies and presence of minor components such as manganese, bismuth, zinc and arsenic. Extraction of cobalt from mined ores. Smalt, zaffre, natural and synthetic ultramarine. Modern equivalents
Lapis Lazuli
No full textInternational audienceThe presence of lapis lazuli minerals in blue pigments, glasses and glazes, its principal sourcing in Badakhshan, Afghanistan, and the identification of its occurrence using the radical polysulfide anion chromophores detectable in low concentrations by resonance Raman spectroscopy. Modern alternatives
Adaptive optimal estimation of irregular mean and covariance functions
No full textInternational audienceWe propose straightforward nonparametric estimators for the mean and the covariance functions of functional data. Our setup covers a wide range of practical situations. The random trajectories are, not necessarily differentiable, have unknown regularity, and are measured with error at discrete design points. The measurement error could be heteroscedastic. The design points could be either randomly drawn or common for all curves. The definition of our nonparametric estimators depends on the local regularity of the stochastic process generating the functional data. We first propose a simple estimator of this local regularity which takes strength from the replication and regularization features of functional data. Next, we use the "smoothing first, then estimate" approach for the mean and the covariance functions. The new nonparametric estimators achieve optimal rates of convergence. They can be applied with both sparsely or densely sampled curves, are easy to calculate and to update, and perform well in simulations. Simulations built upon a real data example on household power consumption illustrate the effectiveness of the new approach
Using the as a Standard Candle to Reach the Top: Calibrating Energy Correlator Based Top Mass Measurements
No full textInternational audienceThe top quark mass plays a central role in our understanding of the Standard Model and its extrapolation to high energies. However, precision measurements of the top quark mass at hadron colliders are notoriously difficult, motivating the development of qualitatively new approaches to take advantage of the enormous datasets of top quarks at the Large Hadron Collider (LHC). Recent advances in jet substructure have enabled the precise theoretical description of angular correlations in energy flux. However, their application to precision mass measurements is less direct since they measure a dimensionless angular scale. Inspired by the use of standard candles in cosmology, we introduce a single energy correlator-based observable that reflects the characteristic angular scales of both the -boson and the top quark masses. This gives direct access to the dimensionless quantity , from which can be extracted in a well-defined short-distance mass scheme as a function of the well-known (our LHC Cepheid variable). We perform a Monte-Carlo-based study to demonstrate the properties of our observable and the statistical feasibility of its extraction from the Run 2 and 3 and High-Luminosity LHC data sets. The resulting has remarkably small uncertainties from non-perturbative effects and is insensitive to the parton distribution functions. We believe that our proposed observable provides a road map for a rich program to achieve a record precision top quark mass measurement at the LHC
Triviality proof for mean-field -theories
No full textInternational audienceThe differential equations of the Wilson renormalization group are a powerful tool to study the Schwinger functions of Euclidean quantum field theory. In particular renormalization theory can be based entirely on inductively bounding their perturbatively expanded solutions. Recently the solutions of these equations for scalar field theory have been analysed rigorously without recourse to perturbation theory, at the cost of restricting to the mean-field approximation. In particular it was shown there that one-component -theory is trivial if the bare coupling constant of the UV regularized theory is not large. This paper presents progress w.r.t. Kopper's previous paper on asymptotically free solutions of the mean-field scalar flow equations: 1. The upper bound on the bare coupling is sent to infinity and the proof is extended to vector models. 2. The unphysical infrared cutoff used for technical simplicity is replaced by a physical mass
Galactic transient sources with the Cherenkov Telescope Array
No full textInternational audienceA wide variety of Galactic sources show transient emission at soft and hard X-ray energies: low-mass and high-mass X-ray binaries containing compact objects (e.g., novae, microquasars, transitional millisecond pulsars, supergiant fast X-ray transients), isolated neutron stars exhibiting extreme variability as magnetars as well as pulsar wind nebulae. Although most of them can show emission up to MeV and/or GeV energies, many have not yet been detected in the TeV domain by Imaging Atmospheric Cherenkov Telescopes. In this paper, we explore the feasibility of detecting new Galactic transients with the Cherenkov Telescope Array (CTA) and the prospects for studying them with Target of Opportunity observations. We show that CTA will likely detect new sources in the TeV regime, such as the massive microquasars in the Cygnus region, low-mass X-ray binaries with low-viewing angle, flaring emission from the Crab pulsar-wind nebula or other novae explosions, among others. We also discuss the multi-wavelength synergies with other instruments and large astronomical facilities
Strategic geometric graphs through mean field games
No full textInternational audienceWe exploit the structure of geometric graphs on Riemannian manifolds to analyze strategicdynamic graphs at the limit, when the number of nodes tends to infinity. This frameworkallows to preserve intrinsic geometrical information about the limiting graph structure, suchas the Ollivier curvature. After introducing the setting, we derive a mean field game system,which models a strategic equilibrium between the nodes. It has the usual structure withthe distinction of being set on a manifold. Finally, we establish existence and uniquenessof solutions to the system when the Hamiltonian is quadratic for a class of non-necessarilycompact Riemannian manifolds, referred to as manifolds of bounded geometry
Searches for Higgs boson production through decays of heavy resonances
No full textInternational audienceThe discovery of the Higgs boson has led to new possible signatures for heavy resonance searches at the LHC. Since then, search channels including at least one Higgs boson plus another particle have formed an important part of the program of new physics searches. In this report, the status of these searches by the CMS Collaboration is reviewed. Searches are discussed for resonances decaying to two Higgs bosons, a Higgs and a vector boson, or a Higgs boson and another new resonance, with proton-proton collision data collected at = 13 TeV in the years 2016-2018. A combination of the results of these searches is presented together with constraints on different beyond-the-standard model scenarios, including scenarios with extended Higgs sectors, heavy vector bosons and extra dimensions. Studies are shown for the first time by CMS on the validity of the narrow-width approximation in searches for the resonant production of a pair of Higgs bosons. The potential for a discovery at the High Luminosity LHC is also discussed
Fourier-Laplace transforms in polynomial Ornstein-Uhlenbeck volatility models
No full textInternational audienceWe consider the Fourier-Laplace transforms of a {broad} class of polynomial Ornstein-Uhlenbeck (OU) volatility models, including the well-known Stein-Stein, Schöbel-Zhu, one-factor Bergomi, and the recently introduced Quintic OU models motivated by the SPX-VIX joint calibration problem. We show the connection between the joint {Fourier-Laplace} functional of the log-price and the integrated variance, and the solution of an infinite dimensional Riccati equation. Next, under some non-vanishing conditions of the Fourier-Laplace transforms, we establish an existence result for such Riccati equation and we provide a discretized approximation of the joint characteristic functional that is exponentially entire. On the practical side, we develop a numerical scheme to solve the stiff infinite dimensional Riccati equations and demonstrate the efficiency and accuracy of the scheme for pricing SPX options and volatility swaps using Fourier and Laplace inversions, with specific examples of the Quintic OU and the one-factor Bergomi models and their calibration to real market data