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
Two-loop HTL Thermodynamics with QuarksFeb 10 2003We calculate the quark contribution to the free energy of a hot quark-gluon plasma to two-loop order using hard-thermal-loop (HTL) perturbation theory. All ultraviolet divergences can be absorbed into renormalizations of the vacuum energy and the HTL ... 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
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
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
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
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
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.
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
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
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
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
Multi-wavelength study of High Mass X-ray BinariesAug 16 2010The INTEGRAL satellite has revealed a major population of supergiant High Mass X-ray Binaries in our Galaxy, revolutionizing our understanding of binary systems and their evolution. This population, constituted of a compact object orbiting around a massive ... More
High Energy Phenomena in Supergiant X-ray BinariesMay 12 2010The INTEGRAL satellite has revealed a major population of supergiant High Mass X-ray Binaries in our Galaxy, revolutionizing our understanding of binary systems and their evolution. This population, constituted of a compact object orbiting around a massive ... More
Nature, formation and evolution of High Mass X-ray BinariesJul 01 2011The aim of this review is to describe the nature, formation and evolution of the three kinds of high mass X-ray binary (HMXB) population: i. systems hosting Be stars (BeHMXBs), ii. systems accreting the stellar wind of supergiant stars (sgHMXBs), and ... More
Fermi-gst: A new view of the gamma-ray skyAug 24 2010The Large Area Telescope on the Fermi gamma-ray Space Telescope (FGST, ex-GLAST) provides unprecedented sensitivity for all-sky monitoring of gamma-ray activity. It is an adequate telescope to detect transient sources, since the observatory scans the ... More
An algorithmic classification of open surfacesSep 13 2012We 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.
AGN Host GalaxiesJul 24 2008Jul 29 2008In this series of four lectures, I discuss four important aspects of AGN host galaxies. In Lecture #1, I address the starburst-AGN connection. First, I briefly review the primary diagnostic tools that are used to quantify and distinguish star formation ... More
Exploring a type-theoretic approach to accessibility constraint modellingMay 22 2008The type-theoretic modelling of DRT that [degroote06] proposed features continuations for the management of the context in which a clause has to be interpreted. This approach, while keeping the standard definitions of quantifier scope, translates the ... More
Obscured High Mass X-Ray Binaries and Supergiant Fast X-ray Transients: Infrared Observations of INTEGRAL SourcesMay 10 2008A new type of high-energy binary system has been revealed by the INTEGRAL satellite. These sources are being unveiled by means of multi-wavelength optical, near- and mid-infrared observations. Among these sources, two distinct classes are appearing: the ... More
Shining Light on Polarizable Dark ParticlesSep 06 2016We investigate the possibilities of searching for a self-conjugate polarizable particle in the self-interactions of light. We first remark that polarizability is described by dimension-6 operators if mediated by messenger states, but is described only ... More
A short guide through integration theorems of generalized distributionsOct 04 2017Aug 27 2018The generalization of Frobenius' theorem to foliations with singularities is usually attributed to Stefan and Sussmann, for their simultaneous discovery around 1973. However, their result is often referred to without caring much on the precise statement, ... More
On a compactification of a Hurwitz space in the wild caseSep 06 2005Let $g$ and $g'$ be two integers and $p$ a prime number. Denote by $\mathscr H_{g, g', p}^c$ the moduli space of morphisms of degree $p$ between smooth curves of genus $g$ and $g'$ and with constant ramification. The purpose of this article is to construct ... More
Quelques calculs d'espaces $\R^i f_* G$ sur des courbesMar 31 2008Mar 17 2009We give some properties (cancellation, representability, stratification) of the sheaf R^i f_* G for an affine relative curve f:U -> S admitting a smooth compactification and G a solvable group.
V-fold cross-validation improved: V-fold penalizationFeb 05 2008Feb 07 2008We study the efficiency of V-fold cross-validation (VFCV) for model selection from the non-asymptotic viewpoint, and suggest an improvement on it, which we call ``V-fold penalization''. Considering a particular (though simple) regression problem, we prove ... 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
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.
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
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
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
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.
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
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
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
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
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
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
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
Galactic Winds: Near and FarSep 03 2003Sep 15 2003Multiwavelength data on star-forming galaxies provide strong evidence for large-scale galactic winds in both nearby and distant objects. The results from recent ground-based and space-borne programs are reviewed. The impact of these winds on the host ... More
Spectroscopic Diagnostics for AGNsJan 08 2002A review of the spectroscopic tools needed to characterize AGNs is presented. This review focusses on ultraviolet, optical and infrared emission-line diagnostics specifically designed to help differentiate AGNs from starburst-dominated galaxies. The strengths ... More
Multiwavelength Observations of Galactic Winds: Near and FarOct 20 2003This paper provides a critical discussion of the observational evidence for winds in our own Galaxy, in nearby star-forming and active galaxies, and in the high-redshift universe. The implications of galactic winds on the formation and evolution of galaxies ... More
How to reveal the mysteries of the most obscured high-energy sources of our Galaxy, discovered by INTEGRAL?Oct 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
Numerical Contractor Renormalization applied to strongly correlated systemsOct 28 2005We demonstrate the utility of effective Hamilonians for studying strongly correlated systems, such as quantum spin systems. After defining local relevant degrees of freedom, the numerical Contractor Renormalization (CORE) method is applied in two steps: ... More
Tree structures for the current fluctuations in the exclusion processNov 18 2009Feb 22 2010We consider the asymmetric simple exclusion process on a ring, with an arbitrary asymmetry between the hopping rates of the particles. Using a functional formulation of the Bethe equations of the model, we derive exact expressions for all the cumulants ... More
Ground state energy of the $δ$-Bose gas at weak coupling from double extrapolationOct 12 2016Nov 04 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 studies gave the expansion $e(\gamma)\simeq\gamma-4\gamma^{3/2}/3\pi+(1/6-1/\pi^{2})\gamma^{2}$. ... More
A family of solvable non-rational conformal field theoriesMar 14 2008May 23 2008We find non-rational conformal field theories in two dimensions, which are solvable due to their correlators being related to correlators of Liouville theory. Their symmetry algebra consists of the dimension-two stress-energy tensor, and two dimension-one ... More
Minimal lectures on two-dimensional conformal field theorySep 29 2016We provide a brief but self-contained review of conformal field theory on the Riemann sphere. We first introduce general axioms such as local conformal invariance, and derive Ward identities and BPZ equations. We then define Liouville theory and minimal ... More
Cordes et D-branes dans les espaces-temps courbesSep 30 2003Oct 10 2003This thesis is devoted to the construction and study of D-branes in some curved space-times in string theory. On the one hand, those D-branes are described geometrically as submanifolds subject to Born-Infeld effective dynamics. On the other hand, they ... More
On the instability of eigenvaluesJan 05 2011This is the proceeding of a talk given in Workshop on Differential Geometry and its applications at Alexandru Ioan Cuza University Ia\c{s}i, Romania, September 2--4, 2009. I explain how positive commutator estimates help in the analysis of embedded eigenvalues ... More
The Nyström method for functional quantization with an application to the fractional Brownian motionSep 07 2010In this article, the so-called "Nystr\"om method" is tested to compute optimal quantizers of Gaussian processes. In particular, we derive the optimal quantization of the fractional Brownian motion by approximating the first terms of its Karhunen-Lo\`eve ... More
A Simplicial Approach to Stratified Homotopy TheoryJan 15 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
On the uniqueness of solutions for the Fubuki gameSep 10 2013We discuss the problem of uniqueness of solutions for the Fubuki game when the diagonal is prescribed.
Contact manifolds with symplectomorphic symplectizationsDec 21 2012We provide examples of contact manifolds of any odd dimension $\geq 5$ which are not diffeomorphic but have exact symplectomorphic symplectizations.
Quantified naturalness from Bayesian statisticsApr 22 2012Nov 20 2012We present a formulation of naturalness made in the framework of Bayesian statistics, which unravels the conceptual problems related to previous approaches. Among other things, the relative interpretation of the measure of naturalness turns out to be ... More
Etude d'un modèle de dynamique des populationsApr 03 2012We study an infinite dimensional dynamical system that was proposed by J.C. Yoccoz and N.G. Yoccoz for modeling the population dynamics of some small rodents. We show an attractor exist in a large domain of the parameter space. Thanks to simulations, ... More
Asymptotics for the norm of Bethe eigenstates in the periodic totally asymmetric exclusion processNov 25 2014Mar 16 2015The normalization of Bethe eigenstates for the totally asymmetric simple exclusion process on a ring of $L$ sites is studied, in the large $L$ limit with finite density of particles, for all the eigenstates responsible for the relaxation to the stationary ... More
Cubic order spin effects in the dynamics and gravitational wave energy flux of compact object binariesNov 15 2014Jan 23 2015We investigate cubic-in-spin effects for inspiralling compact objects binaries, both in the dynamics and the energy flux emitted in gravitational waves, at the leading post-Newtonian order. We use a Lagrangian formalism to implement finite-size effects, ... More
Discrete Renormalization Group for SU(2) Tensorial Group Field TheoryJul 17 2014Nov 20 2014This article provides a Wilsonian description of the perturbatively renormalizable Tensorial Group Field Theory introduced in arXiv:1303.6772 [hep-th] (Commun. Math. Phys. 330, 581-637). It is a rank-3 model based on the gauge group SU(2), and as such ... More
Ground state energy of the $δ$-Bose and Fermi gas at weak coupling from double extrapolationOct 12 2016Jan 05 2017We consider the ground state energy of the Lieb-Liniger gas with $\delta$ interaction in the weak coupling regime $\gamma\to0$. For bosons with repulsive interaction, previous studies gave the expansion $e_{\text{B}}(\gamma)\simeq\gamma-4\gamma^{3/2}/3\pi+(1/6-1/\pi^{2})\gamma^{2}$. ... More
Spatialized Evolutionary prisoner's dilemma: Homogenization and propagation of chaosSep 16 2016Sep 21 2016Epstein introduced an agent-based model called Demographic Prisoner's dilemma. He shows, via simulations, that cooperation in this spatial evolutionary repeated game can be sustained. In order to do proves, we put on this model a particle system framework ... More
Shining Light on Polarizable Dark ParticlesSep 06 2016Apr 09 2017We investigate the possibilities of searching for a self-conjugate polarizable particle in the self-interactions of light. We first observe that polarizability can arise either from the exchange of mediator states or as a consequence of the inner structure ... More
Deformation of a Half-Space from Anelastic Strain Confined in a Tetrahedral VolumeFeb 18 2018Jun 26 2018Deformation in the lithosphere-asthenosphere system can be accommodated by faulting and plastic flow. However, incorporating structural data in models of distributed deformation still represents a challenge. Here, I present solutions for the displacements ... More
Espace de modules des courbes hyperelliptiques stables et une inégalité de Cornalba-Harris-XiaoJul 03 2001Mar 21 2002In this paper, we show an inequality between the degrees of the conductor and the Hodge fiber of a hyperelliptic curve above a discrete valuation ring. For that we have to show theorems about the lifting of $p$-cyclic covers in order to obtain informations ... More