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Verification of the global gyrokinetic stellarator code XGC-S for linear ion temperature gradient driven modesMay 14 2019XGC (X-point Gyrokinetic Code) is a whole-volume, total-f gyrokinetic particle-in-cell code developed for modelling tokamaks. In recent work, XGC has been extended to model more general 3D toroidal magnetic configurations, such as stellarators. These ... More

Gyroaveraging operations using adaptive matrix operatorsFeb 26 2018Apr 20 2018A new adaptive scheme to be used in Particle-In-Cell codes for carrying out gyroaveraging operations with matrices is presented. This new scheme uses an intermediate velocity grid whose resolution is adapted to the local thermal Larmor radius. The charge ... More

A tight-coupling scheme sharing minimum information across a spatial interface between gyrokinetic turbulence codesJun 13 2018Jul 20 2018A new scheme that tightly couples kinetic turbulence codes across a spatial interface is introduced. This scheme evolves from considerations of competing strategies and down-selection. It is found that the use of a composite kinetic distribution function ... More

End-to-End Kernel Learning with Supervised Convolutional Kernel NetworksMay 20 2016In this paper, we propose a new image representation based on a multilayer kernel machine that performs end-to-end learning. Unlike traditional kernel methods, where the kernel is handcrafted or adapted to data in an unsupervised manner, we learn how ... More

Dialog state tracking, a machine reading approach using a memory-enhanced neural networkJun 13 2016Jun 29 2016In an end-to-end dialog system, the aim of dialog state tracking is to accurately estimate a compact representation of the current dialog status from a sequence of noisy observations produced by the speech recognition and the natural language understanding ... More

Extensions of generic measure-preserving actionsJan 21 2012Feb 15 2013We show that, whenever Gamma is a countable abelian group and Delta is a finitely-generated subgroup of Gamma, a generic measure-preserving action of Delta on a standard atomless probability space (X,mu) extends to a free measure-preserving action of ... More

Accretion disc coronae in black hole binariesJul 11 2007Most of the luminosity of accreting black hole is emitted in the X-ray band. This radiation is believed to emerge, through inverse Compton process, from a hot (Te ~ 10^8 -10^9 K) optically thin (Thomson optical depth ~ 1) plasma probably located in the ... More

Jet disc coupling in black hole binariesJun 25 2007In the last decade multi-wavelength observations have demonstrated the importance of jets in the energy output of accreting black hole binaries. The observed correlations between the presence of a jet and the state of the accretion flow provide important ... More

A quasi-spherical inner accretion flow in Seyfert galaxies ?Apr 17 2001We study a phenomenological model for the continuum emission of Seyfert galaxies. In this quasi-spherical accretion scenario, the central X-ray source is constituted by a hot spherical plasma region surrounded by spherically distributed cold dense clouds. ... More

Gluon fusion correction to $H W^+ W^- / H Z Z$ production in the POWHEG-BOXSep 19 2016The study of the Higgs boson properties is one of the most important tasks to be accomplished in the next years, at the Large Hadron Collider (LHC) and at future colliders such as the Future Circular Collider in hadron-hadron mode (FCC-hh), the potential ... More

The Hochschild-Kostant-Rosenberg isomorphism for quantized analytic cyclesSep 04 2011Mar 29 2012In this article, we provide a detailed account of a construction sketched by Kashiwara in an unpublished manuscript concerning generalized HKR isomorphisms for smooth analytic cycles whose conormal exact sequence splits. It enables us, among other applications, ... More

Galois and biGalois objects over monomial non semisimple Hopf algebrasApr 05 2004We describe the Galois objects and biGalois groups of monomial nonsemisimple Hopf algebras. The main feature of our description is the use of modified versions of the second cohomology group of the grouplike elements. These computations generalize the ... More

The Supersymmetric Higgs bounds at the Tevatron and the LHCMay 05 2011MSSM Higgs bosons are the most promising way to discover Higgs physics at hadronic colliders since their cross section is enhanced compared to that of the Standard Model. We will present theoretical predictions for their production and decay in the Higgs$\to ... More

Statistical mechanics of the self-gravitating gasesSep 27 2005The self-gravitating systems are formed by particles interacting through gravity. They describe structure formation in the universe. As a consequence of the long range interaction of gravity, they are inhomogeneous even at thermal equilibrium. We study ... More

Translation and modern interpretation of Laplace's Théorie Analytique des Probabilités, pages 505-512, 516-520Jul 27 2009The text of Laplace, \textit{Sur l'application du calcul des probabilit\'es \`a la philosophie naturelle,} (Th\'eorie Analytique des Probabilit\'es. Troisi\`eme \'Edition. Premier Suppl\'ement), 1820, is quoted in the context of the Gram-Schmidt algorithm. ... More

Infinitesimal deformations of rational surface automorphismsOct 26 2012Feb 14 2016If $X$ is a rational surface without nonzero holomorphic vector field and $f$ is an automorphism of $X$, we study in several examples the Zariski tangent space of the local deformation space of the pair $(X, f)$.

From maps between coloured operads to Swiss-Cheese algebrasMar 23 2016Nov 23 2016In the present work, we extract pairs of topological spaces from maps between coloured operads. We prove that those pairs are weakly equivalent to explicit algebras over the one dimensional Swiss-Cheese operad SC_{1}. Thereafter, we show that the pair ... More

Littlewood-Paley decomposition of operator densities and application to a new proof of the Lieb-Thirring inequalityJun 22 2015The goal of this note is to prove a analogue of the Littewood-Paley decomposition for densities of operators and to use it in the context of Lieb-Thirring inequalities.

Compléments sur les extensions entre séries principales p-adiques et modulo p de G(F)Jul 17 2014Jun 08 2016We complete the results of a previous article. Let $G$ be a split connected reductive group over a finite extension $F$ of $\mathbb{Q}_p$. When $F=\mathbb{Q}_p$, we determine the extensions between unitary continuous $p$-adic and smooth mod $p$ principal ... More

Partitions of large unbalanced bipartitesJan 31 2014Oct 15 2014We compute the asymptotic behaviour of the number of partitions of large vectors $(n_1,n_2)$ of $\mathbb{Z}_+^2$ in the critical regime $n_1 \asymp \sqrt{n_2}$ and in the subcritical regime $n_1 = o(\sqrt{n_2})$. This work completes the results established ... More

Optimization with First-Order Surrogate FunctionsMay 14 2013In this paper, we study optimization methods consisting of iteratively minimizing surrogates of an objective function. By proposing several algorithmic variants and simple convergence analyses, we make two main contributions. First, we provide a unified ... More

Calculs effectifs de congruences entre caractères de DirichletDec 15 2012This article aims to find explicit congruences between Dirichlet characters and gives various results on how to find some effectively on a computer. It ends with concrete examples putting those ideas in application.

A quantum ergodic theorem for mapping class groups action on character varietyJan 22 2016We state a theorem relating the ergodicity of the action of a given subgroup of the mapping class group of a surface on the character variety, to the asymptotic of its invariant subspaces through the Reshetikhin-Turaev representations. As application ... More

On the stability of the Wulff shapeNov 15 2015Given a positive function F on S n satisfying an appropriate con-vexity assumption, we consider hypersurfaces for which a linear combination of some higher order anisotropic curvatures is constant. We define the varia-tional problem for which these hypersurfaces ... More

Local Energy Decay and Diffusive Phenomenon in a Dissipative Wave GuideJan 20 2016We prove the local energy decay for the wave equation in a wave guide with dissipation at the boundary. It appears that for large times the dissipated wave behaves like a solution of a heat equation in the unbounded directions. The proof is based on resolvent ... More

Limiting absorption principle for the dissipative Helmholtz equationMay 04 2009May 29 2009Adapting Mourre's commutator method to the dissipative setting, we prove a limiting absorption principle for a class of abstract dissipative operators. A consequence is the resolvent estimates for the high frequency Helmholtz equation when trapped trajectories ... More

Semiclassical measure for the solution of the Helmholtz equation with an unbounded sourceFeb 04 2013We study the high frequency limit for the dissipative Helmholtz equation when the source term concentrates on a submanifold of R^n. We prove that the solution has a unique semi-classical measure, which is precisely described in terms of the classical ... More

Semiclassical measure for the solution of the dissipative Helmholtz equationNov 23 2009We study the semiclassical measures for the solution of a dissipative Helmholtz equation with a source term concentrated on a bounded submanifold. The potential is not assumed to be non-trapping, but trapped trajectories have to go through the region ... More

Duality of Schramm-Loewner EvolutionsNov 13 2007In this note, we prove a version of the conjectured duality of Schramm-Loewner Evolutions, by establishing exact identities in distribution between some boundary arcs of chordal $\SLE_\kappa$, $\kappa>4$, and appropriate versions of $\SLE_{\hat\kappa}$, ... More

Microcanonical solution of lattice models with long range interactionsOct 11 2001We present a general method to obtain the microcanonical solution of lattice models with long range interactions. As an example, we apply it to the long range Ising chain, focusing on the role of boundary conditions.

A conformally invariant gauge fixing equation and a field strength for the symmetric traceless field over four dimensional conformally flat Einstein spacetimesMay 08 2015Jun 15 2016The conformally invariant symmetric traceless field $A$ is considered on conformally flat Einstein space-time. If $d=4$ this field possess a scalar gauge invariance. In that case, we provide a conformally invariant gauge condition which generalizes in ... More

Geometric interpretation of simplicial formulas for the Chern-Simons invariantNov 13 2010We give a direct interpretation of Neumann's combinatorial formula for the Chern-Simons invariant of a 3-manifold with a representation in PSL(2,C) whose restriction to the boundary takes values in upper triangular matrices. Our construction does not ... More

Derived geometry of the first formal neighborhood of a smooth analytic cycleMay 17 2015Nov 15 2015If $X$ is a smooth scheme of characteristic zero or a complex analytic manifold, and $S$ is a locally split infinitesimal thickening of $X$, we compute explicitly the derived self-intersection of $X$ in $S$.

Quantum automorphism groups of finite graphsFeb 04 1999We determine the quantum automorphism groups of finite graphs. These are quantum subgroups of the quantum permutation groups defined by Wang. The quantum automorphism group is a stronger invariant for finite graphs than the usual one. We get a quantum ... More

Reflected planar Brownian motions, intertwining relations and crossing probabilitiesFeb 20 2003Prompted by an example arising in critical percolation, we study some reflected Brownian motions in symmetric planar domains and show that they are intertwined with one-dimensional diffusions. In the case of a wedge, the reflected Brownian motion is intertwined ... More

SLE and trianglesDec 01 2002Jun 03 2003By analogy with Carleson's observation on Cardy's formula describing crossing probabilities for the scaling limit of critical percolation, we exhibit ``privileged geometries'' for Stochastic Loewner Evolutions with various parameters, for which certain ... More

Four-component relativistic range-separated density-functional theory: Short-range exchange local-density approximationDec 05 2018We lay out the extension of range-separated density-functional theory to a four-component relativistic frame-work using a Dirac-Coulomb-Breit Hamiltonian in the no-pair approximation. This formalism combines a wave-function method for the long-range part ... More

A functional limit convergence towards brownian excursionDec 01 2010We consider a random walk $S$ in the domain of attraction of a standard normal law $Z$, \textit{ie} there exists a positive sequence $a_n$ such that $S_n/a_n$ converges in law towards $Z$. The main result of this note is that the rescaled process $(S_{\lfloor ... More

Compact metrizable groups are isometry groups of compact metric spacesMay 24 2005Jun 22 2005This note is devoted to proving the following result: given a compact metrizable group G, there is a compact metric space K such that G is isomorphic (as a topological group) to the isometry group of K.

A note on Hjorth's oscillation theoremJul 02 2009We reformulate, in the context of continuous logic, an oscillation theorem originally proved by G. Hjorth. We give a proof of the theorem in that setting which is similar to, but simpler than, Hjorth's original one. The point of view presented here clarifies ... More

Internal shocks at the origin of the flat spectral energy distribution of compact jetsOct 16 2012An internal shock model is proposed to interpret the radio to infrared (IR) emission of the compact jets observed in the hard spectral state of X-ray binaries. Assuming that the specific bulk Lorentz factor of the jet at its base varies with a flicker ... More

Singularites des courants d'AhlforsJul 20 2005We prove that an algebraic curve charged by a current coming from an entire curve is rational or elliptic. This answers a question by M. Paun.

Sur le lemme de BrodyJan 02 2007Brody's lemma is a basic tool in complex hyperbolicity. We present a version of it making more precise the localization of an entire curve coming from a diverging sequence of holomorphic discs. As a byproduct we characterize hyperbolicity in terms of ... More

Galois groups of the basic hypergeometric equationsSep 20 2007In this paper we compute the Galois groups of basic hypergeometric equations.

Classification rationnelle et confluence des systemes aux differences singuliers reguliersOct 19 2006By using meromorphic "characters" and "logarithms" built up from Euler's Gamma function, and by using convergent factorial series, we will give, in a first pat, a "normal form" to the solutions of a singular regular system. It will enable us to define ... More

Impact of the spectral hardening of TeV cosmic rays on the prediction of the secondary positron fluxNov 12 2010May 12 2011The rise in the cosmic-ray positron fraction measured by the PAMELA satellite is likely due to the presence of astrophysical sources of positrons, e.g. pulsars, on the kpc scale around the Earth. Nevertheless, assessing the properties of these sources ... More

10 GeV dark matter candidates and cosmic-ray antiprotonsJul 29 2010Nov 03 2010Recent measurements performed with some direct dark matter detection experiments, e.g. CDMS-II and CoGENT (after DAMA/LIBRA), have unveiled a few events compatible with weakly interacting massive particles. The preferred mass range is around 10 GeV, with ... More

Indirect detection of Dark Matter with antimatter: Demystifying the clumpiness boost factorsDec 04 2007The hierarchical scenario of structure formation, in the frame of the $\Lambda$-CDM cosmology, predicts the existence of dark matter (DM) sub-halos down to very small scales, of which the minimal size depends on the microscopic properties of the DM. In ... More

From maps between coloured operads to Swiss-Cheese algebrasMar 23 2016In the present work, we extract pairs of topological spaces from maps between coloured operads. We prove that those pairs are weakly equivalent to explicit algebras over the one dimensional Swiss-Cheese operad SC_{1}. Thereafter, we show that the pair ... More

Complexity and cohomology for cut and projection tilingsApr 01 2008We consider a subclass of tilings, the tilings obtained by cut and projection. Under somewhat standard assumptions, we show that the natural complexity function has polynomial growth. We compute its exponent \alpha in terms of the ranks of certain groups ... More

Double D-term inflationNov 05 1998Mar 02 1999Comparisons of cosmological models to current data show that the presence of a non-trivial feature in the primordial power spectrum of fluctuations, around the scale k=0.05 h/Mpc, is an open and exciting possibility, testable in a near future. This could ... More

Loop quantum cosmology in the cosmic microwave backgroundJun 07 2012The primordial Universe can be used as a laboratory to set constraints on quantum gravity. In the framework of Loop Quantum Cosmology, we show that such a proposal for quantum gravity not only solves for the big bang singularity issue but also naturally ... More

A Remark on Almost Umbilical HypersurfacesOct 26 2007Oct 09 2012In this article, we prove new stability results for almost-Einstein hypersurfaces of the Euclidean space, based on previous eigenvalue pinching results. Then, we deduce some comparable results for almost umbilical hypersurfaces.

The group of bi-Galois objects over the coordinate algebra of the Frobenius-Lusztig kernel of SL(2)Sep 26 2014We construct, for q a root of unity of odd order, an embedding of the projective special linear group PSL(n) into the group of bi-Galois objects over u_q(sl(n))*, the coordinate algebra of the Frobenius-Lusztig kernel of SL(n), which is shown to be an ... More

The information content of galaxy surveysJun 23 2014A large fraction of this thesis is dedicated to the study of the information content of random fields with heavy tails, in particular the lognormal field, a model for the matter density fluctuation field. It is well known that in the nonlinear regime ... More

Decomposition of some Reshitekhin-Turaev representations into irreducible factorsJun 17 2014Oct 14 2014We give the decomposition into irreducible factors of the SU(2) Reshitekhin-Turaev representations of the mapping class group of surfaces when the level is p=4r or p=2r^2 with r an odd prime or when p=2r_1r_2 with r_1,r_2 two distinct odd primes, under ... More

Sur la théorie d'Ahlfors des surfacesNov 07 2013We revisit Ahlfors theory of covering surfaces thanks to Stokes theorem.

Decomposition of the Weil representations at even levels into irreducible factorsOct 01 2013Jan 22 2016We give the decomposition into irreducible factors of Weil representations of the symplectic groups at even levels, generalizing the decompositions of Kloosterman and Cliff-Mc Neilly-Szechtman at odd levels. As application, we derive the decomposition ... More

Stochastic Majorization-Minimization Algorithms for Large-Scale OptimizationJun 19 2013Sep 10 2013Majorization-minimization algorithms consist of iteratively minimizing a majorizing surrogate of an objective function. Because of its simplicity and its wide applicability, this principle has been very popular in statistics and in signal processing. ... More

TASI Lectures on Cosmological PerturbationsFeb 19 2013We present a self-contained summary of the theory of linear cosmological perturbations. We emphasize the effect of the six parameters of the minimal cosmological model, first, on the spectrum of Cosmic Microwave Background temperature anisotropies, and ... More

Formality of derived intersectionsFeb 01 2013Jun 18 2013We study derived intersections of smooth analytic cycles, and provide in some cases necessary and sufficient conditions for this intersection be formal. In particular, if X is a complex submanifold of a complex manifold Y, we prove that X can be quantized ... More

Spectral components in black hole X-ray binariesNov 18 2015This paper summarises our current understanding of the spectral continuum components observed in black hole X-ray binaries. The consequences for theoretical models are discussed with an emphasis on the constraints set by observations on the nature of ... More

Two Pinning Models with Markov disorderDec 15 2010Disordered pinning models deal with the (de)localization tran- sition of a polymer in interaction with a heterogeneous interface. In this paper, we focus on two models where the inhomogeneities at the interface are not independent but given by an irreducible ... More

On quenched and annealed critical curves of random pinning model with finite range correlationsMar 22 2009Feb 23 2011This paper focuses on directed polymers pinned at a disordered and correlated interface. We assume that the disorder sequence is a q-order moving average and show that the critical curve of the annealed model can be expressed in terms of the Perron-Frobenius ... More

Mourre's method for a dissipative form perturbationNov 27 2014We prove uniform resolvent estimates for an abstract operator given by a dissipative perturbation of a self-adjoint operator in the sense of forms. For this we adapt the commutators method of Mourre. We also obtain the limiting absorption principle and ... More

Exponential decay for the Schr{ö}dinger equation on a dissipative waveguideMar 03 2014Jun 01 2015We prove exponential decay for the solution of the Schr{\"o}dinger equation on a dissipative waveguide. The absorption is effective everywhere on the boundary but the geometric control condition is not satisfied. The proof relies on separation of variables ... More

Finite size scaling for homogeneous pinning modelsFeb 07 2008Apr 07 2009Pinning models are built from discrete renewal sequences by rewarding (or penalizing) the trajectories according to their number of renewal epochs up to time $N$, and $N$ is then sent to infinity. They are statistical mechanics models to which a lot of ... More

Typage fort et typage souple des collections topologiques et des transformationsDec 24 2009Topological collections allow to consider uniformly many data structures in programming languages and are handled by functions defined by pattern matching called transformations. We present two type systems for languages with topological collections and ... More

Typing rule-based transformations over topological collectionsDec 24 2009Pattern-matching programming is an example of a rule-based programming style developed in functional languages. This programming style is intensively used in dialects of ML but is restricted to algebraic data-types. This restriction limits the field of ... More

Topological properties of punctual Hilbert schemes of almost-complex fourfolds (II)Jan 02 2010In this article, we study the rational cohomology rings of Voisin's punctual Hilbert schemes $X^{[n]}$ associated to a symplectic compact fourfold $X$. We prove that these rings can be universally constructed from $H^*(X,\mathbb{Q})$ and $c_1(X)$, and ... More

Renaming Global Variables in C Mechanically Proved CorrectJul 08 2016Most integrated development environments are shipped with refactoring tools. However, their refactoring operations are often known to be unreliable. As a consequence, developers have to test their code after applying an automatic refactoring. In this ... More

Stabilizers of closed sets in the Urysohn spaceFeb 20 2005Answering a question of Gao and Kechris, we show that, given any polish group G, there exists a closed subset F of Urysohn's universal metric space U such that G is (topologically) isomorphic to the subgroup of isometries of U which map F onto itself. ... More

Cosovereign Hopf algebrasFeb 04 1999In this paper we define and study the algebraic conterpart of sovereign monoidal categories : cosovereign Hopf algebras.

Hopf-Galois SystemsApr 30 2002We introduce the concept of Hopf-Galois system, a reformulation of the notion of Galois extension of the base field for a Hopf algebra. The main feature of our definition is a generalization of the antipode of an ordinary Hopf algebra. The main application ... More

Commutation relations for SLENov 12 2004Dec 06 2005Schramm-Loewner Evolutions (SLEs) describe a one-parameter family of growth processes in the plane that have particular conformal invariance properties. For instance, SLE can define simple random curves in a simply connected domain. In this paper we are ... More

The skein module of torus knots complementsJan 14 2010Jan 20 2010We compute the Kauffman skein module of the complement of torus knots in S^3. Precisely, we show that these modules are isomorphic to the algebra of Sl(2,C)-characters tensored with the ring of Laurent polynomials.

The Kauffman skein algebra of a surface at $\sqrt{-1}$Feb 06 2008We study the structure of the Kauffman algebra of a surface with parameter equal to sqrt(-1). We obtain an interpretation of this algebra as an algebra of parallel transport operators acting on sections of a line bundle over the moduli space of flat connections ... More

Spinorial Characterization of Surfaces into 3-dimensional homogeneous ManifoldsJun 21 2007We give a spinorial characterization of isometrically immersed surfaces into 3-dimensional homogeneous manifolds with 4-dimensional isometry group in terms of the existence of a particular spinor, called generalized Killing spinor. This generalizes results ... More

Galois reconstruction of finite quantum groupsJun 15 1999We describe a universal factorization for a functor with values in finite-dimensional measured algebras. More precisely we contruct the quantum automorphism group of this functor. This general recontruction result allows us to recapture a finite-dimensional ... More

On the asymptotic stability of steady flows with nonzero flux in two-dimensional exterior domainsMay 12 2016The Navier-Stokes equations in a two-dimensional exterior domain are considered. The asymptotic stability of stationary solutions satisfying a general hypothesis is proven under any $L^2$-perturbation. In particular the general hypothesis is valid if ... More

Algebraic quantum permutation groupsOct 08 2007We discuss some algebraic aspects of quantum permutation groups, working over arbitrary fields. If $K$ is any characteristic zero field, we show that there exists a universal cosemisimple Hopf algebra coacting on the diagonal algebra $K^n$: this is a ... More

Critical percolation in annuli and $SLE_6$Jun 03 2003Building on the identification of the scaling limit of the critical percolation exploration process as a Schramm-Loewner Evolution, we derive a PDE characterization for the crossing probability of an annulus.

Ricci iterations on Kahler classesSep 10 2007Sep 15 2007In this paper we consider the dynamical system involved by the Ricci operator on the space of K\"ahler metrics. A. Nadel has defined an iteration scheme given by the Ricci operator for Fano manifold and asked whether it has some nontrivial periodic points. ... More

Sur une conjecture de Breuil-HerzigMay 25 2014Jun 28 2016Let $G$ be a split $p$-adic reductive group with connected centre and simply connected derived subgroup. We show that certain "chains" of principal series of $G$ do not exist and we establish several properties of the Breuil-Herzig construction $\Pi(\rho)^\mathrm{ord}$. ... More

Complements sur les extensions entre series principales p-adiques et modulo p de G(F)Jul 17 2014Mar 07 2017We complete the results of a previous article. Let $G$ be a split connected reductive group over a finite extension $F$ of $\mathbb{Q}_p$. When $F=\mathbb{Q}_p$, we determine the extensions between unitary continuous $p$-adic and smooth mod $p$ principal ... More

Ptolemy groupoids, shear coordinates and the augmented Teichmuller spaceOct 19 2012May 30 2013We start by describing how ideal triangulations on a surface degenerate under pinching of a multicurve. We use this process to construct a homomorphism from the Ptolemy groupoid of a surface to that of a pinched surface which is natural with respect to ... More

Extrinsci radius pinching in space forms of nonnegative sectional curvatureSep 18 2006We give new estimates for the extrinsic radius of compact hypersurfaces of the Euclidean space and the open hemisphere in terms of high order mean curvatures. Then we prove pinching results corresponding to theses estimates. We show that under a suitable ... More

Extrinsic radius pinching for hypersurfaces of space formsMar 21 2006We prove some pinching results for the extrinsic radius of compact hypersurfaces in space forms. We show that if the pinching condion is strong enough with a dependance on the norm of the second foundamental form, then the hypersurface is diffeomorphic ... More

Dimers and analytic torsion IOct 12 2011Jul 23 2014In the dimer model, a configuration consists of a perfect matching of a fixed graph. If the underlying graph is planar and bipartite, such a configuration is associated to a height function. For appropriate "critical" (weighted) graphs, this height function ... More

Topics on abelian spin models and related problemsDec 19 2011In these notes, we discuss a selection of topics on several models of planar statistical mechanics. We consider the Ising, Potts, and more generally abelian spin models; the discrete Gaussian free field; the random cluster model; and the six-vertex model. ... More

Optimal control of branching diffusion processes: a finite horizon problemNov 21 2015Sep 16 2016In this paper, we aim to develop the theory of optimal stochastic control for branching diffusion processes where both the movement and the reproduction of the particles depend on the control. More precisely, we study the problem of minimizing a criterion ... More

Computing the R of the QR factorization of tall and skinny matrices using MPI_ReduceFeb 23 2010A QR factorization of a tall and skinny matrix with n columns can be represented as a reduction. The operation used along the reduction tree has in input two n-by-n upper triangular matrices and in output an n-by-n upper triangular matrix which is defined ... More

Static Electron-Positron Pair Creation in Strong Fields for a Nonlinear Dirac modelDec 12 2011We consider the Hartree-Fock approximation of Quantum Electrodynamics, with the exchange term neglected. We prove that the probability of static electron-positron pair creation for the Dirac vacuum polarized by an external field of strength $Z$ behaves ... More

Features in the primordial power spectrum of double D-term inflationNov 23 1999Jun 05 2000Recently, there has been some interest for building supersymmetric models of double inflation. These models, realistic from a particle physics point of view, predict a broken-scale-invariant power spectrum of primordial cosmological perturbations, that ... More

The Cosmic Linear Anisotropy Solving System (CLASS) III: Comparision with CAMB for LambdaCDMApr 14 2011May 16 2011By confronting the two independent Boltzmann codes CLASS and CAMB, we establish that for concordance cosmology and for a given recombination history, lensed CMB and matter power spectra can be computed by current codes with an accuracy of 0.01%. We list ... More

A Bourgain-Brezis-Mironescu characterization of higher order Besov-Nikol'skii spacesOct 17 2016We study a class of nonlocal functionals in the spirit of the recent characterization of the Sobolev spaces $W^{1,p}$ derived by Bourgain, Brezis and Mironescu. We show that it provides a common roof to the description of the $BV(\mathbb{R}^N)$, $W^{1,p}(\mathbb{R}^N)$, ... More

A theoretical status of the triple Higgs coupling studies at the LHCAug 26 2014Aug 27 2014Now that a Higgs boson has been discovered at the LHC, measuring its couplings to other particles is the next important step. In order to probe the electroweak symmetry breaking mechanism at its core it is crucial to reconstruct the scalar potential and ... More

An $S$-adic characterization of minimal subshifts with first difference of complexity $1 \leq p(n+1) - p(n) \leq 2$May 02 2013In [Ergodic Theory Dynam. System, 16 (1996) 663--682], S. Ferenczi proved that any minimal subshift with first difference of complexity bounded by 2 is $S$-adic with $\card S \leq 3^{27}$. In this paper, we improve this result by giving an $S$-adic charaterization ... More

End-to-End Kernel Learning with Supervised Convolutional Kernel NetworksMay 20 2016Oct 25 2016In this paper, we introduce a new image representation based on a multilayer kernel machine. Unlike traditional kernel methods where data representation is decoupled from the prediction task, we learn how to shape the kernel with supervision. We proceed ... More

Mean-field limit of generalized Hawkes processesOct 19 2015We generalize multivariate Hawkes processes mainly by including a dependence with respect to the age of the process, i.e. the delay since the last point. Within this class, we investigate the limit behaviour, when n goes to infinity, of a system of n ... More