Results for "Sylvain Petitgirard"

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Poincare's forgotten conferences on wireless telegraphyAug 21 2014At the beginning of the twentieth century while Henri Poincar\'e (1854-1912) was already deeply involved in the developments of wireless telegraphy, he was invited, in 1908, to give a series of lectures at the \'Ecole Sup\'erieure des Postes et T\'el\'egraphes ... More
Observation of Nuclear Quantum Effects and Hydrogen Bond Symmetrisation in High Pressure IceMar 19 2018Hydrogen bond symmetrisations in H-bonded systems triggered by pressure induced nuclear quantum effects (NQEs) is a long-known concept1 but experimental evidences in high-pressure ices have remained elusive with conventional methods2,3. Theoretical works ... More
Cancellation of ladder graphs in an effective expansionAug 20 1997A resummation of ladder graphs is important in cases where infrared, collinear, or light-cone singularities render the loop expansion invalid, especially at high temperature where these effects are often enhanced. It has been noted in some recent examples ... More
NMR close to Mega-Bar PressuresMar 14 2018The past 15 years have seen an astonishing increase in Nuclear Magnetic Resonance (NMR) sensitivity and accessible pressure range in high-pressure NMR experiments, owing to a series of new developments of NMR spectroscopy applied to the diamond anvil ... More
Enhanced photon production rate on the light--coneApr 24 1996Recent studies of the high temperature soft photon production rate on the light--cone using Braaten--Pisarski resummation techniques have found collinear divergences present. We show that there exist a class of terms outside the Braaten--Pisarski framework ... More
Breakdown of the Hard Thermal Loop expansion near the light-coneSep 05 1996We discuss the bremsstrahlung production of soft real and virtual photons in a quark-gluon plasma at thermal equilibrium beyond the Hard Thermal Loop (HTL) resummation. The physics is controlled by the ratio $Q^2/q_0^2$ of the virtuality to the energy. ... More
B1-B2 phase transition in MgO at ultra-high static pressureMar 31 2019Studies of the behaviour of solids at ultra-high pressures, those beyond 200 GPa, contribute to our fundamental understanding of materials properties and allow an insight into the processes happening at such extreme conditions relevant for terrestrial ... More
Pressure induced Hydrogen-Hydrogen interaction in metallic FeH revealed by NMRFeb 08 2019Knowledge of the behavior of hydrogen in metal hydrides is the key for understanding their electronic properties. So far, no experimental methods exist to access these properties beyond 100 GPa, where high-Tc superconductivity emerges. Here, we present ... More
Champs algébriques et foncteur de PicardAug 24 2008This text is my thesis, defended in June 2007, in the status it was at this time. The most important results are contained in the article "Foncteur de Picard d'un champ alg\'ebrique" to appear in "Mathematische Annalen" (see the preprint arXiv:0711.4545). ... More
Partial functional quantization and generalized bridgesJan 28 2011Sep 19 2012In this article, we develop a new approach to functional quantization, which consists in discretizing only a finite subset of the Karhunen-Lo\`eve coordinates of a continuous Gaussian semimartingale $X$. Using filtration enlargement techniques, we prove ... More
A fast nearest neighbor search algorithm based on vector quantizationMay 25 2011In this article, we propose a new fast nearest neighbor search algorithm, based on vector quantization. Like many other branch and bound search algorithms [1,10], a preprocessing recursively partitions the data set into disjointed subsets until the number ... More
Positive commutators, Fermi golden rule and the spectrum of zero temperature Pauli-Fierz HamiltoniansJun 24 2008Jul 08 2008We perform the spectral analysis of a zero temperature Pauli-Fierz system for small coupling constants. Under the hypothesis of Fermi golden rule, we show that the embedded eigenvalues of the uncoupled system disappear and establish a limiting absorption ... More
Discrete D-branes in AdS3 and in the 2d black holeDec 19 2005Aug 11 2006I show how the AdS2 D-branes in the Euclidean AdS3 string theory are related to the continuous D-branes in Liouville theory. I then propose new discrete D-branes in the Euclidean AdS3 which correspond to the discrete D-branes in Liouville theory. These ... More
On sl3 Knizhnik-Zamolodchikov equations and W3 null-vector equationsNov 27 2008Aug 31 2009Starting from Sklyanin's separation of variables for the sl3 Yangian model, we derive the separation of variables for the quantum sl3 Gaudin model. We use the resulting new variables for rewriting the sl3 Knizhnik-Zamolodchikov equations, and comparing ... More
Boundary three-point function on AdS2 D-branesAug 22 2007Jan 10 2008Using the H3+-Liouville relation, I explicitly compute the boundary three-point function on AdS2 D-branes in H3+, and check that it exhibits the expected symmetry properties and has the correct geometrical limit. I then find a simple relation between ... More
A Type System For Call-By-Name ExceptionsJul 12 2009Nov 02 2009We present an extension of System F with call-by-name exceptions. The type system is enriched with two syntactic constructs: a union type for programs whose execution may raise an exception at top level, and a corruption type for programs that may raise ... More
Substitutional Al solute interaction with edge and screw dislocation in Ni: a comparison between atomistic computation and continuum elastic theoryMar 03 2009Molecular static simulations have been performed to study the interaction between a single dislocation and a substitutional Al solute atom in a pure crystal of Ni. When the Al solute is situated at intermediate distance from the slip plane, we find that ... More
Microquasars and JetsJun 01 2005I present an overview of past, present and future research on microquasars and jets, showing that microquasars, i.e. galactic jet sources, are among the best laboratories for high energy phenomena. After remindind the analogy with quasars, I focus on ... More
Multi-wavelength observations of the microquasar XTE J1720-318: a transition from high-soft to low-hard stateNov 17 2006To gain a better understanding of high-energy Galactic sources, we observed the Galactic X-ray binary and black hole candidate XTE J1720-318 in the optical and near-infrared, just after the onset of its X-ray outburst in January, 2003. These observations ... More
The role of microquasars in astroparticle physicsJul 31 2006I present an overview of past, present and future research on microquasars and jets, showing that microquasars, i.e. galactic jet sources, are among the best laboratories for high energy phenomena and astroparticle physics. After reminding the analogy ... More
Tensor hierarchies and Lie $n$-extensions of Leibniz algebrasAug 23 2017Aug 16 2018A Lie $n$-extension of a Leibniz algebra is a particular Lie $n$-algebra that lifts the skew-symmetric part of the Leibniz product in a natural way. In the present paper, we use the relationship between Leibniz algebras and tensor hierarchies to provide ... More
Théorie des déformations équivariantes des morphismes localement d'intersection complèteOct 09 2003This is an expository paper on the subject of the title. It assumes basic scheme theory, commutative and homological algebra.
Contact manifolds and Weinstein h-cobordismsOct 09 2014Dec 01 2014We prove that closed connected contact manifolds of dimension $\geq 5$ related by an h-cobordism with a flexible Weinstein structure become contactomorphic after some kind of stabilization. We also provide examples of non-conjugate contact structures ... More
Reconstruction du squelette des courbes analytiquesApr 05 2019In this work we bring to light some anabelian behaviours of analytic curves in the setting of Berkovich geometry. We show more precisely that the knowledge of the tempered fundamental group of some curves that we call anabelian determines their analytic ... More
Some open 3-manifolds and 3-orbifolds without locally finite canonical decompositionsFeb 11 2008Feb 15 2008We give examples of open 3-manifolds and 3-orbifolds that exhibit pathological behavior with respect to splitting along surfaces (2-suborbifolds) with nonnegative Euler characteristic.
Proof of de Smit's conjecture: a freeness criterionJul 07 2016Jun 16 2017Let $A\to B$ be a morphism of Artin local rings with the same embedding dimension. We prove that any $A$-flat $B$-module is $B$-flat. This freeness criterion was conjectured by de Smit in 1997 and improves Diamond's Theorem 2.1 from his 1997 paper "The ... More
Stratified Homotopy TheoryAug 04 2019A stratified space is a topological space together with a decomposition into strata corresponding to different types of singularities. Examples of such spaces appear everywhere in topology and geometry. The study of stratified spaces involves invariants ... More
Ground state energy of the $δ$-Bose gas at weak coupling from double extrapolationOct 12 2016We consider the ground state energy $e(\gamma)$ of the $\delta$-Bose gas with repulsive interaction in the weak coupling regime $\gamma\to0$, where previous analytical studies gave the expansion $e(\gamma)\simeq\gamma-4\gamma^{3/2}/3\pi+(1/6-1/\pi^{2})\gamma^{2}$. ... More
Fabry-Perot Survey of Emission-Line GalaxiesJan 29 2002The recent results from a deep Fabry-Perot survey of nearby active and star-forming galaxies are presented. Line-emitting material is detected over two orders of magnitude in galactocentric radius, from the 100-pc scale of the active or starbursting nucleus ... More
The Starburst-AGN ConnectionDec 06 2000The issue of a starburst-AGN connection in local and distant galaxies is relevant for understanding galaxy formation and evolution, the star formation and metal enrichment history of the universe, the origin of the extragalactic background at low and ... More
Local Ultraluminous Infrared Galaxies and QuasarsMar 01 2006This paper reviews the recent results from a comprehensive investigation of the most luminous mergers in the local universe, the ultraluminous infrared galaxies (ULIRGs) and the quasars. First, the frequency of occurrence and importance of black hole ... More
Perturbations of C1-diffeomorphisms and dynamics of generic conservative diffeomorphisms of surfaceNov 21 2010In the first part of this text we give a survey of the properties satisfied by the C1-generic conservative diffeomorphisms of compact surfaces. The main result that we will discuss is that a C1-generic conservative diffeomorphism of a connected compact ... More
Fermi-LAT results on Galactic Plane gamma-ray Transient SourcesMay 01 2010The Large Area Telescope on the Fermi gamma-ray Space Telescope provides unprecedented sensitivity for all-sky monitoring of gamma-ray activity. It has detected a few Galactic sources, including 2 gamma-ray binaries and a microquasar. In addition, it ... More
Perturbation de la dynamique de difféomorphismes en topologie C^1 / Perturbation of the dynamics of diffeomorphisms in the C^1-topologyDec 15 2009Les travaux pr\'esent\'es dans ce m\'emoire portent sur la dynamique de diff\'eomorphismes de vari\'et\'es compactes. Pour l'\'etude des propri\'et\'es g\'en\'eriques ou pour la construction d'exemples, il est souvent utile de savoir perturber un syst\`eme. ... More
A combinatorial solution for the current fluctuations in the exclusion processApr 15 2009Jul 31 2009We conjecture an exact expression for the large deviation function of the stationary state current in the partially asymmetric exclusion process with periodic boundary conditions. This expression is checked for small systems using functional Bethe Ansatz. ... More
Choosing a penalty for model selection in heteroscedastic regressionDec 16 2008Jun 04 2010We consider the problem of choosing between several models in least-squares regression with heteroscedastic data. We prove that any penalization procedure is suboptimal when the penalty is a function of the dimension of the model, at least for some typical ... More
D3-branes in NS5-brane backgroundsJan 14 2003May 07 2003We study D3-branes in an NS5-branes background defined by an arbitrary 4d harmonic function. Using a gauge-invariant formulation of Born-Infeld dynamics as well as the supersymmetry condition, we find the general solution for the $\omega$-field. We propose ... More
Duality for commutative group stacksApr 01 2014Apr 09 2015We study in this article the dual of a (strictly) commutative group stack $G$ and give some applications. Using the Picard functor and the Picard stack of $G$, we first give some sufficient conditions for $G$ to be dualizable. Then, for an algebraic stack ... More
Computation of the Central Charge for the Leading Order of the N=2 Super-Yang-Mills Effective ActionMay 26 1999The central charge in the N=2 Super-Yang-Mills theory plays an essential role in the work of Seiberg and Witten as it gives the mass spectrum of the BPS states of the quantum theory. Our aim in this note is to present a direct computation of this central ... More
Finiteness theorems for the Picard objects of an algebraic stackApr 07 2009Dec 16 2011We prove some finiteness theorems for the Picard functor of an algebraic stack, in the spirit of SGA 6, exp. XII and XIII. In particular, we give a stacky version of Raynaud's relative representability theorem, we give sufficient conditions for the existence ... More
Phase diagram of interacting spinless fermions on the honeycomb latticeSep 05 2016Nov 28 2016Fermions hopping on a hexagonal lattice represent one of the most active research field in condensed matter since the discovery of graphene in 2004 and its numerous applications. Another exciting aspect of the interplay between geometry and quantum mechanical ... More
Flowing in Group Field Theory Space: a ReviewMar 07 2016Jul 16 2016We provide a non-technical overview of recent extensions of renormalization methods and techniques to Group Field Theories (GFTs), a class of combinatorially non-local quantum field theories which generalize matrix models to dimension $d \geq 3$. More ... More
Constrained affine Gaudin models and diagonal Yang-Baxter deformationsJul 10 2019We review and pursue further the study of constrained realisations of affine Gaudin models, which form a large class of two-dimensional integrable field theories with gauge symmetries. In particular, we develop a systematic gauging procedure which allows ... More
Group Field Theory in dimension four minus epsilonNov 19 2014Building on an analogy with ordinary scalar field theories, an epsilon expansion for rank-3 tensorial group field theories with gauge invariance condition is introduced. This allows to continuously interpolate between the dimension four group SU(2) X ... More
Complexity Bounds for Ordinal-Based TerminationJul 22 2014`What more than its truth do we know if we have a proof of a theorem in a given formal system?' We examine Kreisel's question in the particular context of program termination proofs, with an eye to deriving complexity bounds on program running times. ... More
Probing the finite density equation of state of QCD via resummed perturbation theoryJul 08 2014In this Ph.D. thesis, the primary goal is to present a recent investigation of the finite density thermodynamics of hot and dense quark-gluon plasma. As we are interested in a temperature regime, in which naive perturbation theory is known to lose its ... More
Spectrum of the totally asymmetric simple exclusion process on a periodic lattice -- first excited statesApr 04 2014Aug 13 2014We consider the spectrum of the totally asymmetric simple exclusion process on a periodic lattice of $L$ sites. The first eigenstates have an eigenvalue with real part scaling as $L^{-3/2}$ for large $L$ with finite density of particles. Bethe ansatz ... More
Large $N$ limit of irreducible tensor models: $O(N)$ rank-$3$ tensors with mixed permutation symmetryMar 07 2018Jun 05 2018It has recently been proven that in rank three tensor models, the anti-symmetric and symmetric traceless sectors both support a large $N$ expansion dominated by melon diagrams [arXiv:1712.00249 [hep-th]]. We show how to extend these results to the last ... More
A Simplicial Approach to Stratified Homotopy TheoryJan 15 2018Nov 11 2018In this article we consider the homotopy theory of stratified spaces through a simplicial point of view. We first consider a model category of filtered simplicial sets over some fixed poset $P$, and show that it is a simplicial combinatorial model category. ... More
Electric field vector mapping of guided ionization waves at atmospheric pressureSep 10 2017In this study, the dynamic of guided ionization wave (IW) generated by an atmospheric pressure plasma jet (APPJ) device in plasma gun configuration is experimentally investigated. The present work focuses on the properties of the intense electric field ... More
Enveloping Lie superalgebras and Killing-ricci forms of Bol superalgebrasJul 28 2017In this paper, enveloping Lie superalgebras of Bol superalgebras are introduced. The notion of Killing-Ricci forms and invariant forms of these superalgebras are investigated as generalization of the ones of Bol algebras.
Cross-validationMar 09 2017This text is a survey on cross-validation. We define all classical cross-validation procedures, and we study their properties for two different goals: estimating the risk of a given estimator, and selecting the best estimator among a given family. For ... More
Limit value of dynamic zero-sum games with vanishing stage durationMar 30 2016We consider two person zero-sum games where the players control, at discrete times {tn} induced by a partition $\Pi$ of R + , a continuous time Markov state process. We prove that the limit of the values v$\Pi$ exist as the mesh of $\Pi$ goes to 0. The ... More
Current fluctuations and large deviations for periodic TASEP on the relaxation scaleSep 03 2015Nov 16 2015The one-dimensional totally asymmetric simple exclusion process (TASEP) with $N$ particles on a periodic lattice of $L$ sites is an interacting particle system with hopping rates breaking detailed balance. The total time-integrated current of particles ... More
Fibred coarse embeddability of box spaces and proper isometric affine actions on $L^p$ spacesAug 20 2015We show the necessary part of the following theorem : a finitely generated, residually finite group has property $PL^p$ (i.e. it admits a proper isometric affine action on some $L^p$ space) if, and only if, one (or equivalently, all) of its box spaces ... More
Current fluctuations for totally asymmetric exclusion on the relaxation scaleOct 09 2014Jan 21 2015The fluctuations of the current for the one-dimensional totally asymmetric exclusion process with $L$ sites are studied in the relaxation regime of times $T\sim L^{3/2}$. Using Bethe ansatz for the periodic system with an evolution conditioned on special ... More
Spaces with labelled partitions and isometric affine actions on Banach spacesDec 31 2013Aug 20 2015We define the structure of spaces with labelled partitions which generalizes the structure of spaces with measured walls and study the link between actions by automorphisms on spaces with labelled partitions and isometric affine actions on Banach spaces, ... More
Properties of the Ornstein-Uhlenbeck bridgeOct 21 2013Jan 22 2014This paper presents a study of the properties of the Ornstein-Uhlenbeck bridge, specifically, we derive its Karhunen-Lo\`eve expansion for any value of the initial variance and mean-reversion parameter (or mean-repulsion if negative). We also show that ... More
A JSJ splitting for triangulated open 3-manifoldsFeb 11 2008We give a sufficient condition for an open 3-manifold to admit a decomposition along properly embedded open annuli and tori, generalizing the toric splitting of Jaco-Shalen and Johannson.
Model selection by resampling penalizationJun 17 2009In this paper, a new family of resampling-based penalization procedures for model selection is defined in a general framework. It generalizes several methods, including Efron's bootstrap penalization and the leave-one-out penalization recently proposed ... More
Conformal field theory on the planeJun 17 2014Feb 25 2016We provide an introduction to conformal field theory on the plane in the conformal bootstrap approach. We introduce the main ideas of the bootstrap approach to quantum field theory, and how they apply to two-dimensional theories with local conformal symmetry. ... More
Minisuperspace limit of the AdS3 WZNW modelDec 22 2009May 28 2010We derive the three-point function of the AdS3 WZNW model in the minisuperspace limit by Wick rotation from the H3+ model. The result is expressed in terms of Clebsch-Gordan coefficients of the Lie algebra sl(2,R). We also introduce a covariant basis ... More
Knizhnik-Zamolodchikov equations and spectral flow in AdS3 string theoryJul 12 2005Aug 28 2005I generalize the Knizhnik-Zamolodchikov equations to correlators of spectral flowed fields in AdS3 string theory. If spectral flow is preserved or violated by one unit, the resulting equations are equivalent to the KZ equations. If spectral flow is violated ... More
Expansion of the propagation of chaos for Bird and Nanbu systemsJan 22 2009Oct 18 2016The Bird and Nanbu systems are particle systems used to approximate the solution of the mollied Boltzmann equation. In particular, they have the propagation of chaos property. Following [GM94, GM97, GM99], we use coupling techniques and results on branching ... More
Fluctuations and skewness of the current in the partially asymmetric exclusion processMay 27 2008Jul 17 2008We use functional Bethe Ansatz equations to calculate the cumulants of the total current in the partially asymmetric exclusion process. We recover known formulas for the first two cumulants (mean value of the current and diffusion constant) and obtain ... More
Obscured sources and Supergiant Fast X-ray Transients: new classes of high mass X-ray binariesOct 01 2007A new type of high-energy binary systems has been revealed by the INTEGRAL satellite. These sources are in the course of being unveiled by means of multi-wavelength optical, near- and mid-infrared observations. Among these sources, two distinct classes ... More
Phase diagram of interacting spinless fermions on the honeycomb latticeSep 05 2016Fermions hopping on a hexagonal lattice represent one of the most active research field in condensed matter since the discovery of graphene in 2004 and its numerous applications. Another exciting aspect of the interplay between geometry and quantum mechanical ... More
Numerical study of magnetization plateaux in the spin-1/2 Heisenberg antiferromagnet on the checkerboard latticeNov 15 2016We present numerical evidence that the spin-1/2 Heisenberg model on the two-dimensional checkerboard lattice exhibits several magnetization plateaux for m=0, 1/4, 1/2 and 3/4, where m is the magnetization normalized by its saturation value. These incompressible ... More
Proof of de Smit's conjecture: a freeness criterionJul 07 2016Let $A\to B$ be a morphism of Artin local rings with the same embedding dimension. We prove that any $A$-flat $B$-module is $B$-flat. This freeness criterion was conjectured by de Smit in 1997 and improves Diamond's Theorem 2.1 from his 1997 paper "The ... More
Foncteur de Picard d'un champ algébriqueNov 28 2007In this article we study the Picard functor and the Picard stack of an algebraic stack. We give a new and direct proof of the representability of the Picard stack. We prove that it is quasi-separated, and that the connected component of the identity is ... More
Conformal field theory on the planeJun 17 2014May 09 2017We provide an introduction to conformal field theory on the plane in the conformal bootstrap approach. We introduce the main ideas of the bootstrap approach to quantum field theory, and how they apply to two-dimensional theories with local conformal symmetry. ... More
A spherical decomposition for Riemannian open 3-manifoldsMay 12 2006We show that open 3-manifolds that have a locally finite decomposition along 2-spheres are characterized by the existence of a Riemannian metric with respect to which the second homotopy group of the manifold is generated by small elements.
A finite presentation of the mapping class group of an oriented surfaceNov 27 1998We give a finite presentation of the mapping class group of an oriented (possibly bounded) surface of genus greater or equal than 1, considering Dehn twists on a very simple set of curves.
The Configuration space integral for links in R^3May 09 2000Nov 18 2002The perturbative expression of Chern-Simons theory for links in Euclidean 3-space is a linear combination of integrals on configuration spaces. This has successively been studied by Guadagnini, Martellini and Mintchev, Bar-Natan, Kontsevich, Bott and ... More
Rationality Results for the Configuration Space Integral of KnotsJan 07 1999The perturbative Chern-Simons theory for knots in Euclidean space is a linear combination of integrals on configuration spaces. This has been successively studied by Bott and Taubes, Altschuler and Freidel, and Yang. We study it again in terms of degree ... More
Extrapolation methods and Bethe ansatz for the asymmetric exclusion processApr 29 2016Oct 18 2016The one-dimensional asymmetric simple exclusion process (ASEP), where $N$ hard-core particles hop forward with rate $1$ and backward with rate $q<1$, is considered on a periodic lattice of $L$ site. Using KPZ universality and previous results for the ... More
High Mass X-ray Binaries: Progenitors of double neutron star systemsOct 26 2015In this review I briefly describe the nature of the three kinds of High-Mass X-ray Binaries (HMXBs), accreting through: (i) Be circumstellar disc, (ii) supergiant stellar wind, and (iii) Roche lobe filling supergiants. A previously unknown population ... More
Complexity Hierarchies Beyond ElementaryDec 19 2013Feb 04 2016We introduce a hierarchy of fast-growing complexity classes and show its suitability for completeness statements of many non elementary problems. This hierarchy allows the classification of many decision problems with a non-elementary complexity, which ... More
Tensorial methods and renormalization in Group Field TheoriesOct 14 2013In this thesis, we study the structure of Group Field Theories (GFTs) from the point of view of renormalization theory. Such quantum field theories are found in approaches to quantum gravity related to Loop Quantum Gravity (LQG) on the one hand, and to ... More
A sufficient condition for a Rational Differential Operator to generate an Integrable SystemMay 11 2016For a rational differential operator $L=AB^{-1}$, the Lenard-Magri scheme of integrability is a sequence of functions $F_n, n\geq 0$, such that (1) $B(F_{n+1})=A(F_n)$ for all $n \geq 0$ and (2) the functions $B(F_n)$ pairwise commute. We show that, assuming ... More
Taming systematic uncertainties at the LHC with the central limit theoremMar 09 2016Aug 30 2016We study the simplifications occurring in any likelihood function in the presence of a large number of small systematic uncertainties. We find that the marginalisation of these uncertainties can be done analytically by means of second-order error propagation, ... More
Finite-time fluctuations for the totally asymmetric exclusion processNov 12 2015Mar 07 2016The one-dimensional totally asymmetric simple exclusion process (TASEP), a Markov process describing classical hard-core particles hopping in the same direction, is considered on a periodic lattice of $L$ sites. The relaxation to the non-equilibrium steady ... More
A Jump Distance-based Bayesian analysis method to unveil fine single molecule transport featuresJun 03 2015Jun 05 2015Single-molecule tracking (SMT) methods are under considerable expansion in many fields of cell biology, as the dynamics of cellular components in biological mechanisms becomes increasingly relevant. Despite the development of SMT technologies, it is still ... More
Modèle théorique de la contraction musculaire squelettique : ressorts entropiques, processus stochastiques et mécanique classique (A theoretical model of skeletal muscular contraction : entropic springs, stochastic processes and classical mechanics)Nov 17 2013The model analyzes the muscle fiber as a deformable system for which experimental data are determinated with the help of the laws of Newtonian mechanic. The model predicts the four transient phases for the shortening of a muscle fiber according to a force ... More
A Variational Topological Neural Model for Cascade-based Diffusion in NetworksDec 28 2018Many works have been proposed in the literature to capture the dynamics of diffusion in networks. While some of them define graphical markovian models to extract temporal relationships between node infections in networks, others consider diffusion episodes ... More
Kurtoses and high order cumulants: Insights from resummed perturbation theoryNov 08 2013Dec 23 2013Cumulants of conserved charges provide important information about the physics of the quark-gluon plasma around the phase transition region, as they are by construction sensitive to changes in the degrees of freedom of the system. In this brief proceedings ... More
B-spline techniques for volatility modelingJun 05 2013Jun 12 2015This paper is devoted to the application of B-splines to volatility modeling, specifically the calibration of the leverage function in stochastic local volatility models and the parameterization of an arbitrage-free implied volatility surface calibrated ... More
An algorithmic classification of open surfacesSep 13 2012Jun 18 2018We propose a formulation for the homeomorphism problem for open n-dimensional manifolds and use the Kerekjarto classification theorem to solve this problem for n=2.
Minimal penalties and the slope heuristics: a surveyJan 22 2019Birg{\'e} and Massart proposed in 2001 the slope heuristics as a way to choose optimally from data an unknown multiplicative constant in front of a penalty. It is built upon the notion of minimal penalty, and it has been generalized since to some 'minimal-penalty ... More
On 2d CFTs that interpolate between minimal modelsSep 11 2018May 28 2019We investigate exactly solvable two-dimensional conformal field theories that exist at generic values of the central charge, and that interpolate between A-series or D-series minimal models. When the central charge becomes rational, correlation functions ... More
Quantum Forces from Dark Matter and Where to Find ThemMay 29 2017Apr 15 2018We observe that sub-GeV Dark Matter (DM) induces Casimir-Polder forces between nucleons, that can be accessed by experiments from nuclear to molecular scales. We calculate the nucleon-nucleon potentials arising in the DM effective theory and note that ... More
The general setting for Shape AnalysisApr 07 2015In shape analysis, the concept of shape spaces has always been vague, requiring a case-by-case approach for every new type of shape. In this paper, we give a general definition for an abstract space of shapes in a manifold. This notion encompasses every ... More
Some applications of Ricci flow to 3-manifoldsJan 31 2008We decribe and announce some results (joint with G. Besson, L. Bessieres, M. Boileau and J.Porti) about the geometry and topology of 3-manifolds. Most of the article is primarily intended as an introduction for nonexperts to geometrization of 3-manifolds, ... More
Large-scale conformal rigidity in dimension threeOct 28 2002We define a complete Riemannian manifold X to be large-scale conformally rigid if all groups that are quasi-isometric to some complete Riemannian manifold of bounded geometry conformal to X are quasi-isometric to X. We prove that many 3-manifolds, including ... More
Partial hyperbolicity far from homoclinic bifurcationsSep 29 2008We prove that any diffeomorphism of a compact manifold can be C^1-approximated by a diffeomorphism which exhibits a homoclinic bifurcation (a homoclinic tangency or a heterodimensional cycle) or by a diffeomorphism which is partially hyperbolic (its chain-recurrent ... More
Birth of homoclinic intersections: a model for the central dynamics of partially hyperbolic systemsMay 15 2006Jan 26 2010We prove a conjecture of J. Palis: any diffeomorphism of a compact manifold can be C1-approximated by a Morse-Smale diffeomorphism or by a diffeomorphism having a transverse homoclinic intersection. ----- Cr'eation d'intersection homoclines : un mod`ele ... More
Hardy inequality and asymptotic eigenvalue distribution for discrete LaplaciansJun 03 2011Oct 25 2013In this paper we study in detail some spectral properties of the magnetic discrete Laplacian. We identify its form-domain, characterize the absence of essential spectrum and provide the asymptotic eigenvalue distribution.
Unboundedness of adjacency matrices of locally finite graphsOct 19 2009Mar 16 2010Given a locally finite simple graph so that its degree is not bounded, every self-adjoint realization of the adjacency matrix is unbounded from above. In this note we give an optimal condition to ensure it is also unbounded from below. We also consider ... More
AdS2 D-branes in AdS3 spacetimeJul 10 2002I review some recent progress in understanding the properties of AdS2 branes in AdS3. Different methods - classical string motion, Born-Infeld dynamics, boundary states - are evocated and compared.
The AGN Paradigm: Radio-Quiet ObjectsNov 11 2002The current paradigm for radio-quiet AGNs is reviewed, taking into account new results from recent large-scale surveys carried out from the ground and from space. Topics include structure of the central engine, AGN demography, fueling/triggering processes, ... More