Results for "Sébastien Renaux-Petel"

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Primordial non-Gaussianities after Planck 2015: an introductory reviewAug 27 2015Deviations from Gaussian statistics of the cosmological density fluctuations, so-called primordial non-Gaussianities (NG), are one of the most informative fingerprints of the origin of structures in the universe. Indeed, they can probe physics at energy ... More
Aspects of massive gravityDec 23 2015We report here on two works on Lorentz invariant massive gravity. In the first part, we derive the decoupling limit of massive gravity on de Sitter, relying on embedding de Sitter into an higher dimensional Minkowski spacetime. This enables us to identify ... More
Geometrical Destabilization of InflationOct 05 2015Sep 20 2016We show the existence of a general mechanism by which heavy scalar fields can be destabilized during inflation, relying on the fact that the curvature of the field space manifold can dominate the stabilizing force from the potential and destabilize inflationary ... More
Perturbations in generalized multi-field inflationJan 07 2008May 31 2008We study the linear perturbations of multi-field inflationary models governed by a Lagrangian which is a general function of the scalar fields and of a global kinetic term combining their spacetime gradients with an arbitrary field space metric. Our analysis ... More
On reaching the adiabatic limit in multi-field inflationMay 23 2014Dec 29 2014We calculate the scalar spectral index $n_s$ and the tensor-to-scalar ratio $r$ in a class of recently proposed two-field no-scale inflationary models in supergravity. We show that, in order to obtain correct predictions, it is crucial to take into account ... More
A Statistical Approach to Multifield Inflation: Many-field Perturbations Beyond Slow RollJul 02 2012Oct 02 2012We study multifield contributions to the scalar power spectrum in an ensemble of six-field inflationary models obtained in string theory. We identify examples in which inflation occurs by chance, near an approximate inflection point, and we compute the ... More
Multifield Cosmological Perturbations at Third Order and the Ekpyrotic TrispectrumJun 02 2009Sep 14 2009Using the covariant formalism, we derive the equations of motion for adiabatic and entropy perturbations at third order in perturbation theory for cosmological models involving two scalar fields. We use these equations to calculate the trispectrum of ... More
Inflationary stochastic anomaliesJun 26 2018Feb 25 2019The stochastic approach aims at describing the long-wavelength part of quantum fields during inflation by a classical stochastic theory. It is usually formulated in terms of Langevin equations, giving rise to a Fokker-Planck equation for the probability ... More
Flattened non-Gaussianities from the effective field theory of inflation with imaginary speed of soundMay 31 2018Nov 06 2018Inflationary perturbations in multi-field theories can exhibit a transient tachyonic instability as a consequence of their non-trivial motion in the internal field space. When an effective single-field description is applicable, the resulting theory is ... More
Geometrical destabilization, premature end of inflation and Bayesian model selectionJun 06 2017Nov 03 2017By means of Bayesian techniques, we study how a premature ending of inflation, motivated by geometrical destabilization, affects the observational evidences of typical inflationary models. Large field models are worsened, and inflection point potentials ... More
Primordial fluctuations and non-Gaussianities in sidetracked inflationApr 30 2018Jul 27 2018Heavy scalar fields can undergo an instability during inflation as a result of their kinetic couplings with the inflaton. This is known as the geometrical destabilization of inflation, as it relies on the effect of the negative curvature of the field-space ... More
On backreaction effects in geometrical destabilisation of inflationJan 29 2019We study the geometrical instability arising in multi-field models of inflation with negatively-curved field space. We analyse how the homogeneous background evolves in presence of geometrical destabilisation, and show that, in simple models, a kinematical ... More
Hyper non-Gaussianities in inflation with strongly non-geodesic motionFeb 08 2019Several recent proposals to embed inflation into high-energy physics rely on inflationary dynamics characterized by a strongly non-geodesic motion in negatively curved field space. This naturally leads to a transient instability of perturbations on sub-Hubble ... More
Nonlinear perturbations of cosmological scalar fields with non-standard kinetic termsOct 14 2008Dec 09 2008We adopt a covariant formalism to derive exact evolution equations for nonlinear perturbations, in a universe dominated by two scalar fields. These scalar fields are characterized by non-canonical kinetic terms and an arbitrary field space metric, a situation ... More
Primordial fluctuations and non-Gaussianities from multifield DBI Galileon inflationAug 01 2011Jan 03 2012We study a cosmological scenario in which the DBI action governing the motion of a D3-brane in a higher-dimensional spacetime is supplemented with an induced gravity term. The latter reduces to the quartic Galileon Lagrangian when the motion of the brane ... More
Massive Gravity on de Sitter and Unique Candidate for Partially Massless GravityJun 15 2012Jan 10 2013We derive the decoupling limit of Massive Gravity on de Sitter in an arbitrary number of space-time dimensions d. By embedding d-dimensional de Sitter into d+1-dimensional Minkowski, we extract the physical helicity-1 and helicity-0 polarizations of the ... More
Multi-field DBI inflation: introducing bulk forms and revisiting the gravitational wave constraintsFeb 17 2009We study multi-field Dirac-Born-Infeld (DBI) inflation models, taking into account the NS-NS and R-R bulk fields present in generic flux compactifications. We compute the second-order action, which governs the behaviour of linear cosmological perturbations, ... More
Primordial fluctuations and non-Gaussianities in multi-field DBI inflationApr 19 2008We study Dirac-Born-Infeld (DBI) inflation models with multiple scalar fields. We show that the adiabatic and entropy modes propagate with a common effective sound speed and are thus amplified at the sound horizon crossing. In the small sound speed limit, ... More
Primordial perturbations and non-Gaussianities in DBI and general multi-field inflationJun 02 2008We study cosmological perturbations in general inflation models with multiple scalar fields and arbitrary kinetic terms, with special emphasis on the multi-field extension of Dirac-Born-Infeld (DBI) inflation. We compute the second-order action governing ... More
Spectral distortions in the cosmic microwave background polarizationDec 16 2013Mar 21 2014We compute the spectral distortions of the Cosmic Microwave Background (CMB) polarization induced by non-linear effects in the Compton interactions between CMB photons and cold intergalactic electrons. This signal is of the $y$-type and is dominated by ... More
Coexistence of Near-Field and Far-Field Sources: the Angular Resolution LimitApr 03 2013Apr 16 2013Passive source localization is a well known inverse problem in which we convert the observed measurements into information about the direction of arrivals. In this paper we focus on the optimal resolution of such problem. More precisely, we propose in ... More
Hierarchical inference for genome-wide association studies: a view on methodology with softwareMay 08 2018We provide a view on high-dimensional statistical inference for genome-wide association studies (GWAS). It is in part a review but covers also new developments for meta analysis with multiple studies and novel software in terms of an R-package hierinf. ... More
Some results on the Weiss-Weinstein bound for conditional and unconditional signal models in array processingNov 28 2012In this paper, the Weiss-Weinstein bound is analyzed in the context of sources localization with a planar array of sensors. Both conditional and unconditional source signal models are studied. First, some results are given in the multiple sources context ... More
Neveu-Schwarz and operators algebras III: Subfactors and Connes fusionOct 01 2010Oct 07 2010This paper is the third of a series giving a self-contained way from the Neveu-Schwarz algebra to a new series of irreducible subfactors. Here we introduce the local von Neumann algebra of the Neveu-Schwarz algebra, to obtain Jones-Wassermann subfactors ... More
Almost sure invariance principle for dynamical systems by spectral methodsJul 08 2009Feb 09 2011We prove the almost sure invariance principle for stationary R^d--valued processes (with dimension-independent very precise error terms), solely under a strong assumption on the characteristic functions of these processes. This assumption is easy to check ... More
Martin boundary of random walks with unbounded jumps in hyperbolic groupsFeb 21 2013Nov 03 2015Given a probability measure on a finitely generated group, its Martin boundary is a natural way to compactify the group using the Green function of the corresponding random walk. For finitely supported measures in hyperbolic groups, it is known since ... More
Higher order terms for the quantum evolution of a Wick observable within the Hepp methodFeb 19 2011The Hepp method is the coherent state approach to the mean field dynamics for bosons or to the semiclassical propagation. A key point is the asymptotic evolution of Wick observables under the evolution given by a time-dependent quadratic Hamiltonian. ... More
Improved bounds for reduction to depth 4 and depth 3Apr 21 2013May 16 2014Koiran showed that if a $n$-variate polynomial of degree $d$ (with $d=n^{O(1)}$) is computed by a circuit of size $s$, then it is also computed by a homogeneous circuit of depth four and of size $2^{O(\sqrt{d}\log(d)\log(s))}$. Using this result, Gupta, ... More
Bringing Information Credibility Back Into Transparency: The Case for a Global Monitoring System Of Green House Gas EmissionsJul 07 2016The goal of climate change governance is to stabilize greenhouse gas concentrations. This requires the reduction of anthropogenic global net emissions. In the pursuit of such a reduction, knowledge of greenhouse gas sources and sinks is critical to define ... More
A Markov partition for Jeandel-Rao aperiodic Wang tilingsMar 14 2019We define a Markov partition for a $\mathbb{Z}^2$-rotation on the 2-dimensional torus whose associated symbolic dynamical system is a minimal and aperiodic Wang shift defined by 19 Wang tiles. We define another partition for another $\mathbb{Z}^2$-rotation ... More
Neveu-Schwarz and operators algebras I: Vertex operators superalgebrasOct 01 2010Oct 07 2010This paper is the first of a series giving a self-contained way from the Neveu-Schwarz algebra to a new series of irreducible subfactors. Here we present an elementary, progressive and self-contained approch to vertex operator superalgebra. We then build ... More
Chern-Simons Invariants of Torus LinksMar 15 2010Jan 03 2011We compute the vacuum expectation values of torus knot operators in Chern-Simons theory, and we obtain explicit formulae for all classical gauge groups and for arbitrary representations. We reproduce a known formula for the HOMFLY invariants of torus ... More
On the coldness of the local Hubble flow: the role of baryonsFeb 24 2010Jun 14 2010(Abridged) Our aim is to investigate whether the presence of baryons can have any significant influence on the properties of the local Hubble flow which has proved to be "cold". We use two cosmological zoom simulations in the standard LCDM cosmology with ... More
A geometric derivation of the linear Boltzmann equation for a particle interacting with a Gaussian random fieldJul 05 2011Jun 25 2012In this article the linear Boltzmann equation is derived for a particle interacting with a Gaussian random field, in the weak coupling limit, with renewal in time of the random field. The initial data can be chosen arbitrarily. The proof is geometric ... More
Low energy scales of Kondo lattices: mean-field perspectiveMar 11 2009A review of the low temperature properties of Kondo lattice systems is presented within the mean-field approximation, focusing on the different characteristic energy scales. The Kondo temperature, T_K, and the Fermi liquid coherence energy, T_0, are analyzed ... More
Some properties of meta-stable supersymmetry-breaking vacua in Wess-Zumino modelsJul 24 2006As a contribution to the current efforts to understand supersymmetry-breaking by meta-stable vacua, we study general properties of supersymmetry-breaking vacua in Wess-Zumino models: we show that tree-level degeneracy is generic, explore some constraints ... More
Conditional Moments of Anticipative $α$-Stable Markov ProcessesMay 14 2018The anticipative $\alpha$-stable autoregression of order 1 (AR(1)) is a stationary Markov process undergoing explosive episodes akin to bubbles in financial time series data. Although featuring infinite variance, integer conditional moments up to order ... More
A self-similar aperiodic set of 19 Wang tilesFeb 09 2018Jul 24 2018We define a Wang tile set $\mathcal{U}$ of cardinality 19 and show that the set $\Omega_\mathcal{U}$ of all valid Wang tilings $\mathbb{Z}^2\to\mathcal{U}$ is self-similar, aperiodic and is a minimal subshift of $\mathcal{U}^{\mathbb{Z}^2}$. Thus $\mathcal{U}$ ... More
A note on matrices mapping a positive vector onto its element-wise inverseAug 21 2017For any primitive matrix $M\in\mathbb{R}^{n\times n}$ with positive diagonal entries, we prove the existence and uniqueness of a positive vector $\mathbf{x}=(x_1,\dots,x_n)^t$ such that $M\mathbf{x}=(\frac{1}{x_1},\dots,\frac{1}{x_n})^t$. The contribution ... More
A counterexample to a question of Hof, Knill and SimonJul 05 2013In this article, we give a negative answer to a question of Hof, Knill and Simon (1995) concerning purely morphic sequences obtained from primitive morphism containing an infinite number of palindromes. Proven for the binary alphabet by B. Tan in 2007, ... More
Neveu-Schwarz and operators algebras II: Unitary series and charactersOct 01 2010Oct 07 2010This paper is the second of a series giving a self-contained way from the Neveu-Schwarz algebra to a new series of irreducible subfactors. Here we give a unitary complete proof of the classification of the unitary series of the Neveu-Schwarz algebra, ... More
On rotarily transitive graphsMay 19 2016From the point of view of discrete geometry, the class of locally finite transitive graphs is a wide and important one. The subclass of Cayley graphs is of particular interest, as testifies the development of geometric group theory. Recall that Cayley ... More
Ergodicity and indistinguishability in percolation theoryOct 04 2012Nov 13 2014This paper explores the link between the ergodicity of the clus-ter equivalence relation restricted to its infinite locus and the indis-tinguishability of infinite clusters. It is an important element of the dictionary connecting orbit equivalence and ... More
Asymptotic Analysis of a Non-Linear Non-Local Integro-Differential Equation Arising from Bosonic Quantum Field DynamicsDec 19 2012We introduce a one parameter family of non-linear, non-local integro-differential equations and its limit equation. These equations originate from a derivation of the linear Boltzmann equation using the framework of bosonic quantum field theory. We show ... More
A fast Monte-Carlo method with a Reduced Basis of Control Variates applied to Uncertainty Propagation and Bayesian EstimationFeb 03 2012The Reduced-Basis Control-Variate Monte-Carlo method was introduced recently in [S. Boyaval and T. Leli\`evre, CMS, 8 2010] as an improved Monte-Carlo method, for the fast estimation of many parametrized expected values at many parameter values. We provide ... More
Latt{è}s maps and the interior of the bifurcation locusJan 19 2018Feb 21 2018We show the existence of open sets of bifurcations near Latt{\`e}s maps of sufficiently high degree. In particular, every Latt{\`e}s map has an iterate which is in the closure of the interior of the bifurcation locus. To show this, we design a method ... More
A Core Theory of Delay SystemsJul 09 2017We introduce a framework for the description of a large class of delay-differential algebraic systems, in which we study three core problems: first we characterize abstractly the well-posedness of the initial-value problem, then we design a practical ... More
Precise measurement of the $K_{e2}/K_{μ2}$ branching ratio and search for new physics beyond the Standard ModelNov 08 2016The E36 experiment recently conducted at J-PARC by the TREK Collaboration will provide a precise mesurement of the decay ratio $ R_K = \Gamma(K^+ \rightarrow e^+\nu_e) / \Gamma(K^+ \rightarrow \mu^+\nu_{\mu}) $ with the aim of testing lepton universality, ... More
Sharp Asymptotics for the Truncated Two-Point Function of the Ising Model with a Positive FieldOct 16 2018We prove that the correction to exponential decay of the truncated two points function in the homogeneous positive field Ising model is $c\|x\|^{-(d-1)/2}$. The proof is based on the development in the random current representation of a "modern" Ornstein-Zernike ... More
Topology optimization in the framework of the linear Boltzmann equation - a method for designing optimal nuclear equipment and particle opticsOct 02 2018Oct 09 2018In this study, we describe a procedure of topology optimization in the framework of the linear Boltzmann equation, implemented using a reference Monte-Carlo particle transport code. This procedure can design complex structures that optimize the transport ... More
Variations around Eagleson's Theorem on mixing limit theorems for dynamical systemsMar 30 2018Eagleson's Theorem asserts that, given a probability-preserving map, ifrenormalized Birkhoff sums of a function converge in distribution, thenthey also converge with respect to any probability measure which isabsolutely continuous with respect to the ... More
On geometric aspects of the SUSY Fokas-Gel'fand immersion formulaJun 20 2017Mar 09 2018In this paper, we develop a new geometric characterization for the supersymmetric versions of the Fokas--Gel'fand formula for the immersion of soliton supermanifolds with two bosonic and two fermionic independent variables into Lie superalgebras. In order ... More
A fictitious domain approach for a mixed finite element method solving the two-phase Stokes problem with surface tension forcesJul 25 2018Apr 01 2019In this article we study a mixed finite element formulation for solving the Stokes problem with general surface forces that induce a jump of the normal trace of the stress tensor, on an interface that splits the domain into two subdomains. Equality of ... More
Torus Knots in Lens Spaces & Topological StringsAug 26 2013Jun 22 2014We study the invariant of knots in lens spaces defined from quantum Chern-Simons theory. By means of the knot operator formalism, we derive a generalization of the Rosso-Jones formula for torus knots in L(p,1). In the second part of the paper, we propose ... More
A fictitious domain approach for a mixed finite element method solving the two-phase Stokes problem with surface tension forcesJul 25 2018In this article we study a mixed finite element formulation for solving the Stokes problem with general boundary forces that induce a jump of the normal trace of the stress tensor, on an interface that splits the domain into two subdomains. Equality of ... More
Cellular automata on a $G$-setMay 26 2011We extend the usual definition of cellular automaton on a group in order to deal with a new kind of cellular automata, like cellular automata in the hyperbolic plane and we explore some properties of these cellular automata. This definition also allows ... More
Substitutive structure of Jeandel-Rao aperiodic tilingsAug 23 2018We describe the substitutive structure of Jeandel-Rao aperiodic Wang tilings $\Omega_0$. We introduce twelve sets of Wang tiles $\{\mathcal{T}_{i}\}_{1\leq i\leq 12}$ together with their associated Wang shifts $\{\Omega_{i}\}_{1\leq i\leq 12}$. Using ... More
Hybrid Inflation: Multi-field Dynamics and Cosmological ConstraintsSep 26 2011The dynamics of hybrid models is usually approximated by the evolution of a scalar field slowly rolling along a nearly flat valley. Inflation ends with a waterfall phase, due to a tachyonic instability. This final phase is usually assumed to be nearly ... More
Stabilization of a fluid-solid system, by the deformation of the self-propelled solid. Part I: The linearized systemMar 27 2013Jan 02 2014This paper is the first part of a work which consists in proving the stabilization to zero of a fluid-solid system, in dimension 2 and 3. The considered system couples a deformable solid and a viscous incompressible fluid which satisfies the incompressible ... More
Existence of 3D strong solutions for a system modeling a deformable solid inside a viscous incompressible fluidMar 01 2013Jul 07 2014In this paper we study a coupled system modeling the movement of a deformable solid immersed in a fluid. For the solid we consider a given deformation that has to obey several physical constraints. The motion of the fluid is modeled by the incompressible ... More
Persistent homoclinic tangencies and infinitely many sinks for residual sets of automorphisms of low degree in C^{3}Nov 07 2016We show that there exists a polynomial automorphism $f$ of $\mathbb{C}^{3}$ of degree 5 such that for every automorphism $g$ sufficiently close to $f$, $g$ admits a tangency between the stable and unstable laminations of some hyperbolic set. As a consequence, ... More
Convex Optimization: Algorithms and ComplexityMay 20 2014Nov 16 2015This monograph presents the main complexity theorems in convex optimization and their corresponding algorithms. Starting from the fundamental theory of black-box optimization, the material progresses towards recent advances in structural optimization ... More
Analyticity of the entropy and the escape rate of random walks in hyperbolic groupsSep 23 2015We consider random walks on a non-elementary hyperbolic group endowed with a word distance. To a probability measure on the group are associated two numerical quantities, the rate of escape and the entropy. On the set of admissible probability measures ... More
Growth of normalizing sequences in limit theorems for conservative mapsMar 30 2018We consider normalizing sequences that can give rise to nondegenerate limittheorems for Birkhoff sums under the iteration of a conservative map. Mostclassical limit theorems involve normalizing sequences that are polynomial,possibly with an additional ... More
Supersymmetric and R symmetric vacua in Wess-Zumino modelsAug 16 2007In the context of supersymmetric Wess-Zumino models with an R symmetry, we find some simple conditions on the R-charge content of the theory that imply the presence or absence of supersymmetric and R-symmetric vacua. The main result of this work is that ... More
On integrability aspects of the supersymmetric sine-Gordon equationMar 23 2017In this paper we study certain integrability properties of the supersymmetric sine-Gordon equation. We construct Lax pairs with their zero-curvature representations which are equivalent to the supersymmetric sine-Gordon equation. From the fermionic linear ... More
Path prediction of aggregated $α$-stable moving averages using semi-norm representationsSep 10 2018For $(X_t)$ a two-sided $\alpha$-stable moving average, this paper studies the conditional distribution of future paths given a piece of observed trajectory when the process is far from its central values. Under this framework, vectors of the form $\boldsymbol{X}_t=(X_{t-m},\ldots,X_t,X_{t+1},\ldots,X_{t+h})$, ... More
Substitutive structure of Jeandel-Rao aperiodic tilingsAug 23 2018Apr 11 2019We describe the substitutive structure of Jeandel-Rao aperiodic Wang tilings $\Omega_0$. We introduce twelve sets of Wang tiles $\{\mathcal{T}_{i}\}_{1\leq i\leq 12}$ together with their associated Wang shifts $\{\Omega_{i}\}_{1\leq i\leq 12}$. Using ... More
Stabilization of a fluid-solid system, by the deformation of the self-propelled solid. Part II: The nonlinear systemMar 27 2013Jan 02 2014In this second part we prove that the full nonlinear fluid-solid system introduced in Part I is stabilizable by deformations of the solid that have to satisfy nonlinear constraints. Some of these constraints are physical and guarantee the self-propelled ... More
$3$-dimensional Continued Fraction Algorithms Cheat SheetsNov 26 2015Multidimensional Continued Fraction Algorithms are generalizations of the Euclid algorithm and find iteratively the gcd of two or more numbers. They are defined as linear applications on some subcone of $\mathbb{R}^d$. We consider multidimensional continued ... More
Tensor C*-categories arising as bimodule categories of II_1 factorsDec 17 2011Mar 06 2013We prove that if C is a tensor C*-category in a certain class, then there exists an uncountable family of pairwise non stably isomorphic II_1 factors (M_i) such that the bimodule category of M_i is equivalent to C for all i. In particular, we prove that ... More
Application of a nudging technique to thermoacoustic tomographyDec 03 2011ThermoAcoustic Tomography (TAT) is a promising, non invasive, medical imaging technique whose inverse problem can be formulated as an initial condition reconstruction. In this paper, we introduce a new algorithm originally designed to correct the state ... More
A Taxonomy of Daemons in Self-stabilizationOct 03 2011We survey existing scheduling hypotheses made in the literature in self-stabilization, commonly referred to under the notion of daemon. We show that four main characteristics (distribution, fairness, boundedness, and enabledness) are enough to encapsulate ... More
Asymptotic expansions at any time for scalar fractional SDEs with Hurst index $H>1/2$Mar 27 2007Oct 24 2008We study the asymptotic expansions with respect to $h$ of \[\mathrm{E}[\Delta_hf(X_t)],\qquad \mathrm{E}[\Delta_hf(X_t)|\mathscr{F}^X_t]\quadand\quad \mathrm{E}[\Delta_hf(X_t)|X_t],\] where $\Delta_hf(X_t)=f(X_{t+h})-f(X_t)$, when $f:\mathbb {R}\to\mathbb{R}$ ... More
Sparse recovery with unknown variance: a LASSO-type approachJan 02 2011Nov 05 2012We address the issue of estimating the regression vector $\beta$ in the generic $s$-sparse linear model $y = X\beta+z$, with $\beta\in\R^{p}$, $y\in\R^{n}$, $z\sim\mathcal N(0,\sg^2 I)$ and $p> n$ when the variance $\sg^{2}$ is unknown. We study two LASSO-type ... More
Le droit du numérique : une histoire à préserverOct 12 2012Although the history of informatics is recent, this field poses unusual problems with respect to its preservation. These problems are amplified by legal issues, digital law being in itself a subject matter whose history is also worth presenting in a computer ... More
Optimal feeding is optimal swimming for all Péclet numbersSep 01 2011Cells swimming in viscous fluids create flow fields which influence the transport of relevant nutrients, and therefore their feeding rate. We propose a modeling approach to the problem of optimal feeding at zero Reynolds number. We consider a simplified ... More
Parameterizable Byzantine Broadcast in Loosely Connected NetworksJan 17 2013Dec 08 2013We consider the problem of reliably broadcasting information in a multihop asynchronous network, despite the presence of Byzantine failures: some nodes are malicious and behave arbitrarly. We focus on non-cryptographic solutions. Most existing approaches ... More
Limiting Byzantien Influence in Multihop Asynchronous NetworksJan 27 2012We consider the problem of reliably broadcasting information in a multihop asyn- chronous network that is subject to Byzantine failures. That is, some nodes of the network can exhibit arbitrary (and potentially malicious) behavior. Existing solutions ... More
Macroscopic Facilitation of Glassy Relaxation Kinetics: Ultra Stable Glass Films with Front-Like Thermal ResponseAug 26 2010The recent experimental fabrication of ultra stable glass films via vapour deposition [Science 315, 353 (2007)] and the observation of front-like response to the annealing of these films [Phys.Rev.Lett. 102, 065503 (2009)], have raised important questions ... More
Some particular self-interacting diffusions: Ergodic behaviour and almost sure convergenceJul 19 2007Jan 04 2012This paper deals with some self-interacting diffusions $(X_t,t\geq 0)$ living on $\mathbb{R}^d$. These diffusions are solutions to stochastic differential equations: \[\mathrm{d}X_t=\mathrm{d}B_t-g(t)\nabla V(X_t-\bar{\mu}_t)\,\mathrm{d}t,\] where $\bar{\mu}_t$ ... More
Bayesian posterior consistency in the functional randomly shifted curves modelDec 21 2012Mar 12 2013In this paper, we consider the so-called Shape Invariant Model which stands for the estimation of a function $f^0$ submitted to a random translation of law $g^0$ in a white noise model. We are interested in such a model when the law of the deformations ... More
The algorithm of noisy k-meansAug 15 2013In this note, we introduce a new algorithm to deal with finite dimensional clustering with errors in variables. The design of this algorithm is based on recent theoretical advances (see Loustau (2013a,b)) in statistical learning with errors in variables. ... More
Almost global existence of weak solutions for the nonlinear elastodynamics system with general strain energyJul 12 2016The aim of this paper is to prove the existence of almost global weak solutions for the unsteady nonlinear elastodynamics system in dimension $d=2$ or $3$, for a range of strain energy density functions satisfying some given assumptions. These assumptions ... More
A deconvolution approach to estimation of a common shape in a shifted curves modelDec 18 2008Oct 20 2010This paper considers the problem of adaptive estimation of a mean pattern in a randomly shifted curve model. We show that this problem can be transformed into a linear inverse problem, where the density of the random shifts plays the role of a convolution ... More
Tropical and non-Archimedean limits of degenerating families of volume formsMay 17 2016We study the asymptotic behavior of volume forms on a degenerating family of compact complex manifolds. Under rather general conditions, we prove that the volume forms converge in a natural sense to a Lebesgue-type measure on a certain simplicial complex. ... More
Rigidity of square-tiled interval exchange transformationsFeb 20 2017We look at interval exchange transformations defined as first return maps on the set of diagonals of a flow of direction $\theta$ on a square-tiled surface: using a combinatorial approach, we show that, when the surface has at least one true singularity ... More
Context-Aware Learning for Neural Machine TranslationMar 12 2019Interest in larger-context neural machine translation, including document-level and multi-modal translation, has been growing. Multiple works have proposed new network architectures or evaluation schemes, but potentially helpful context is still sometimes ... More
A corrected quantitative version of the Morse lemmaOct 10 2018There is a gap in the proof of the main theorem in the article [ShCh13a] on optimal bounds for the Morse lemma in Gromov-hyperbolic spaces. We correct this gap, showing that the main theorem of [ShCh13a] is correct. We also describe a computer certification ... More
Variational Calibration of Computer ModelsOct 29 2018Bayesian calibration of black-box computer models offers an established framework to obtain a posterior distribution over model parameters. Traditional Bayesian calibration involves the emulation of the computer model and an additive model discrepancy ... More
Asymptotics of even-even correlations in the Ising modelApr 23 2018Nov 26 2018We consider finite-range ferromagnetic Ising models on $\mathbb{Z}^d$ in the regime $\beta<\beta_c$. We analyze the behavior of the prefactor to the exponential decay of $\mathrm{Cov}(\sigma_A,\sigma_B)$, for arbitrary finite sets $A$ and $B$ of even ... More
Morphing for faster computations in transformation opticsJul 07 2014Aug 01 2014We propose to use morphing algorithms to deduce some approximate wave pictures of scattering by cylindrical invisibility cloaks of various shapes deduced from the exact computation (e.g. using a finite element method) of scattering by cloaks of two given ... More
A Kolmogorov-Like Exact Relation for Compressible Polytropic TurbulenceAug 19 2013Dec 07 2013Compressible hydrodynamic turbulence is studied under the assumption of a polytropic closure. Following Kolmogorov, we derive an exact relation for some two-point correlation functions in the asymptotic limit of a high Reynolds number.
Abstract Interpretation using a Language of Symbolic ApproximationDec 28 2017The traditional abstract domain framework for imperative programs suffers from several shortcomings; in particular it does not allow precise symbolic abstractions. To solve these problems, we propose a new abstract interpretation framework, based on symbolic ... More
Subadditive and Multiplicative Ergodic TheoremsSep 25 2015A result for subadditive ergodic cocycles is proved that provides more delicate information than Kingman's subadditive ergodic theorem. As an application we deduce a multiplicative ergodic theorem generalizing an earlier result of Karlsson-Ledrappier, ... More
Subgaussian concentration inequalities for geometrically ergodic Markov chainsDec 04 2014Jul 21 2015We prove that an irreducible aperiodic Markov chain is geometrically ergodic if and only if any separately bounded functional of the stationary chain satisfies an appropriate subgaussian deviation inequality from its mean.
Uniformly balanced words with linear complexity and prescribed letter frequenciesAug 18 2011We consider the following problem. Let us fix a finite alphabet A; for any given d-uple of letter frequencies, how to construct an infinite word u over the alphabet A satisfying the following conditions: u has linear complexity function, u is uniformly ... More
Phoretic self-propulsion at finite Péclet numbersMar 14 2014Phoretic self-propulsion is a unique example of force- and torque-free motion on small scales. The classical framework describing the flow field around a particle swimming by self-diffusiophoresis neglects the advection of the solute field by the flow ... More
On Byzantine Broadcast in Planar GraphsJan 14 2013Dec 07 2013We consider the problem of reliably broadcasting information in a multihop asynchronous network in the presence of Byzantine failures: some nodes may exhibit unpredictable malicious behavior. We focus on completely decentralized solutions. Few Byzantine-robust ... More
On Byzantine Broadcast in Loosely Connected NetworksSep 05 2012We consider the problem of reliably broadcasting information in a multihop asynchronous network that is subject to Byzantine failures. Most existing approaches give conditions for perfect reliable broadcast (all correct nodes deliver the authentic message ... More