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Results for "Joyce van Meurs"

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Many-particle limits and non-convergence of dislocation wall pile-upsApr 06 2017The starting point of our analysis is a class of one-dimensional interacting particle systems with two species. The particles are confined to an interval and exert a nonlocal, repelling force on each other, resulting in a nontrivial equilibrium configuration. ... More
Multimodal Machine Learning-based Knee Osteoarthritis Progression Prediction from Plain Radiographs and Clinical DataApr 12 2019Knee osteoarthritis (OA) is the most common musculoskeletal disease without a cure, and current treatment options are limited to symptomatic relief. Prediction of OA progression is a very challenging and timely issue, and it could, if resolved, accelerate ... More
L^2-Theory for non-symmetric Ornstein-Uhlenbeck semigroups on domainsJul 04 2012Oct 26 2012We present some new results on analytic Ornstein-Uhlenbeck semigroups and use them to extend recent work of Da Prato and Lunardi for Ornstein-Uhlenbeck semigroups on open domains O to the non-symmetric case. Denoting the generator of the semigroup by ... More
Boundary-layer analysis of a pile-up of walls of edge dislocations at a lockFeb 20 2015Jun 06 2016In this paper we analyse the behaviour of a pile-up of vertically periodic walls of edge dislocations at an obstacle, represented by a locked dislocation wall. Starting from a continuum non-local energy $E_\gamma$ modelling the interactions$-$at a typical ... More
Smash Products of Calabi-Yau Algebras by Hopf AlgebrasDec 03 2015Jan 08 2019Let H be a Hopf algebra and A be an H-module algebra. This article investigates when the smash product A#H is (skew) Calabi-Yau, has Van den Bergh duality or is Artin-Schelter regular or Gorenstein. In particular, if A and H are skew Calabi-Yau, then ... More
The universal cover of an algebra without double bypassJul 25 2005Nov 17 2006Let A be a basic finite dimensional and connected algebra over an algebraically closed field k with zero characteristic. If the ordinary quiver of A has no double bypasses, we show that A admits a Galois covering which satisfies a universal property with ... More
Some new homology and cohomology theories of manifolds and orbifoldsSep 18 2015For each manifold or effective orbifold $Y$ and commutative ring $R$, we define a new homology theory $MH_*(Y;R)$, $M$-$homology$, and a new cohomology theory $MH^*(Y;R)$, $M$-$cohomology$. For $MH_*(Y;R)$ the chain complex $(MC_*(Y;R),\partial)$ is generated ... More
Duality for Differential Operators of Lie-Rinehart AlgebrasSep 12 2017Dec 21 2018Let (S,L) be a Lie-Rinehart algebra over a commutative ring R. This article proves that, if S is flat as an R-module and has Van den Bergh duality in dimension n, and if L is finitely generated and projective with constant rank d as an S-module, then ... More
A new construction of compact torsion-free $G_2$-manifolds by gluing families of Eguchi-Hanson spacesJul 28 2017Jul 17 2018We give a new construction of compact Riemannian 7-manifolds with holonomy $G_2$. Let $M$ be a torsion-free $G_2$-manifold (which can have holonomy a proper subgroup of $G_2$) such that $M$ admits an involution $\iota$ preserving the $G_2$-structure. ... More
Upscaling of the dynamics of dislocation wallsNov 04 2014We perform the discrete-to-continuum limit passage for a microscopic model describing the time evolution of dislocations in a one dimensional setting. This answers the related open question raised by Geers et al. in [GPPS13]. The proof of the upscaling ... More
Discrete-to-continuum limits of particles with an annihilation ruleJul 30 2018Dec 29 2018In the recent trend of extending discrete-to-continuum limit passages for gradient flows of single-species particle systems with singular and nonlocal interactions to particles of opposite sign, any annihilation effect of particles with opposite sign ... More
Exploring mass loss, low-Z accretion, and convective overshoot in solar models to mitigate the solar abundance problemJan 05 2010Feb 23 2010Solar models using the new lower abundances of Asplund et al. (2005, 2009) or Caffau et al. (2008, 2009) do not agree as well with helioseismic inferences as models that use the higher Grevesse & Noels (1993) or Grevesse & Sauval (1998) abundances. Adopting ... More
Context-based Word Acquisition for Situated Dialogue in a Virtual WorldJan 16 2014To tackle the vocabulary problem in conversational systems, previous work has applied unsupervised learning approaches on co-occurring speech and eye gaze during interaction to automatically acquire new words. Although these approaches have shown promise, ... More
Thermal Brownian motorMay 31 2005Aug 03 2005Recently, a thermal Brownian motor was introduced [Van den Broeck, Kawai and Meurs, Phys. Rev. Lett. (2004)], for which an exact microscopic analysis is possible. The purpose of this paper is to review some further properties of this construction, and ... More
Asymptotic analysis of boundary layers in a repulsive particle systemSep 12 2016This paper studies the boundary behaviour at mechanical equilibrium at the ends of a finite interval of a class of systems of interacting particles with monotone decreasing repulsive force. Our setting covers pile-ups of dislocations, dislocation dipoles ... More
Overview of large N QCD with chemical potential at weak and strong couplingJan 24 2013In this note we summarize the results from a longer article on obtaining the QCD phase diagram as a function of the temperature and chemical potential at large Nc and large Nf in the weak and the strong coupling limits. The weak coupling phase diagram ... More
Phase diagrams of SU(N) gauge theories with fermions in various representationsMar 26 2009Jul 03 2009We minimize the one-loop effective potential for SU(N) gauge theories including fermions with finite mass in the fundamental (F), adjoint (Adj), symmetric (S), and antisymmetric (AS) representations. We calculate the phase diagram on S^1 x R^3 as a function ... More
Exotic phases of finite temperature SU(N) gauge theoriesOct 13 2008We calculate the phase diagrams at high temperature of SU(N) gauge theories with massive fermions by minimizing the one-loop effective potential. Considering fermions in the adjoint (Adj) representation at various N we observe a variety of phases when ... More
Commonsense Reasoning for Natural Language Understanding: A Survey of Benchmarks, Resources, and ApproachesApr 02 2019Commonsense knowledge and commonsense reasoning are some of the main bottlenecks in machine intelligence. In the NLP community, many benchmark datasets and tasks have been created to address commonsense reasoning for language understanding. These tasks ... More
Interactive Learning of State Representation through Natural Language Instruction and ExplanationOct 07 2017One significant simplification in most previous work on robot learning is the closed-world assumption where the robot is assumed to know ahead of time a complete set of predicates describing the state of the physical world. However, robots are not likely ... More
The nef cone volume of generalized Del Pezzo surfacesMar 07 2007Jul 24 2007We compute a naturally defined measure of the size of the nef cone of a Del Pezzo surface. The resulting number appears in a conjecture of Manin on the asymptotic behavior of the number of rational points of bounded height on the surface. The nef cone ... More
Combinatorial Models for the Variety of Complete QuadricsOct 09 2016Nov 28 2017We develop several combinatorial models that are useful in the study of the $SL_n$-variety $\mathcal{X}$ of complete quadrics. Barred permutations parameterize the fixed points of the action of a maximal torus $T$ of $SL_n$, while $\mu$-involutions parameterize ... More
An efficient numerical model for liquid water uptake in porous material and its parameter estimationFeb 27 2019The goal of this study is to propose an efficient numerical model for the predictions of capillary adsorption phenomena in a porous material. The Scharfetter-Gummel numerical scheme is proposed to solve an advection-diffusion equation with gravity flux. ... More
Is adding charcoal to soil a good method for CO2 sequestration? - Modeling a spatially homogeneous soilAug 27 2012Jul 09 2013Carbon sequestration is the process of capture and long-term storage of atmospheric carbon dioxide (CO2) with the aim to avoid dangerous climate change. In this paper, we propose a simple mathematical model (a coupled system of nonlinear ODEs) to capture ... More
Dynamics of screw dislocations: a generalised minimising-movements scheme approachSep 03 2015Feb 29 2016The gradient flow structure of the model introduced in [CG99] for the dynamics of screw dislocations is investigated by means of a generalised minimising-movements scheme approach. The assumption of a finite number of available glide directions, together ... More
Rectification of thermal fluctuations in ideal gasesJul 07 2004We calculate the systematic average speed of the adiabatic piston and a thermal Brownian motor, introduced in [Van den Broeck, Kawai and Meurs, \emph{Microscopic analysis of a thermal Brownian motor}, to appear in Phys. Rev. Lett.], by an expansion of ... More
Convergence and non-convergence of many-particle evolutions with multiple signsOct 11 2018We address the question of convergence of evolving interacting particle systems as the number of particles tends to infinity. We consider two types of particles, called positive and negative. Same-sign particles repel each other, and opposite-sign particles ... More
Upscaling of dislocation walls in finite domainsAug 23 2013We wish to understand the macroscopic plastic behaviour of metals by upscaling the micro-mechanics of dislocations. We consider a highly simplified dislocation network, which allows our microscopic model to be a one dimensional particle system, in which ... More
Exact microscopic analysis of a thermal Brownian motorDec 30 2003Jan 01 2004We study a genuine Brownian motor by hard disk molecular dynamics and calculate analytically its properties, including its drift speed and thermal conductivity, from microscopic theory.
Particle dynamics subject to impenetrable boundaries: existence and uniqueness of mild solutionsDec 21 2018We consider the dynamics of particle systems where the particles are confined by impenetrable barriers to a bounded, possibly non-convex domain $\Omega$. When particles hit the boundary, we consider an instant change in velocity, which turns the systems ... More
Precision Analysis of Evolved StarsMar 12 2019Evolved stars dominate galactic spectra, enrich the galactic medium, expand to change their planetary systems, eject winds of a complex nature, produce spectacular nebulae and illuminate them, and transfer material between binary companions. While doing ... More
Representation theory of partial relation extensionsApr 05 2016Let C be a finite dimensional algebra of global dimension at most two. A partial relation extension is any trivial extension of C by a direct summand of its relation C-C-bimodule. When C is a tilted algebra, this construction provides an intermediate ... More
Uniqueness results for special Lagrangians and Lagrangian mean curvature flow expanders in C^mApr 01 2014May 01 2015We prove two main results: (a) Suppose $L$ is a closed, embedded, exact special Lagrangian $m$-fold in ${\mathbb C}^m$ for $m\ge 3$ asymptotic at infinity to the union $\Pi_1\cup\Pi_2$ of two transverse special Lagrangian planes $\Pi_1,\Pi_2$ in ${\mathbb ... More
Point Spread Function Estimation in X-ray Imaging with Partially Collapsed Gibbs SamplingSep 26 2017The point spread function (PSF) of a translation invariant imaging system is its impulse response, which cannot always be measured directly. This is the case in high energy X-ray radiography, and it must be estimated from images of calibration objects ... More
Consistency Relations for the Conformal MechanismDec 13 2012Apr 11 2013We systematically derive the consistency relations associated to the non-linearly realized symmetries of theories with spontaneously broken conformal symmetry but with a linearly-realized de Sitter subalgebra. These identities relate (N+1)-point correlation ... More
Astro2020 Science White Paper: Stellar Physics and Galactic Archeology using Asteroseismology in the 2020'sMar 19 2019Asteroseismology is the only observational tool in astronomy that can probe the interiors of stars, and is a benchmark method for deriving fundamental properties of stars and exoplanets. Over the coming decade, space-based and ground-based observations ... More
Independently Controllable FactorsAug 03 2017Aug 25 2017It has been postulated that a good representation is one that disentangles the underlying explanatory factors of variation. However, it remains an open question what kind of training framework could potentially achieve that. Whereas most previous work ... More
Infrared Spectroscopy of Symbiotic Stars. XII. The Neutron Star SyXB System 4U 1700+24 = V934 HerculisDec 20 2018V934 Her = 4U1700+24 is an M giant-neutron star (NS) X-ray symbiotic (SyXB) system. Employing optical and infrared radial velocities spanning 29 years combined with the extensive velocities in the literature, we compute the spectroscopic orbit of the ... More
Can we quickly flag Ultra-long Gamma-Ray Bursts?Apr 09 2019Ultra-long Gamma-Ray Bursts are a class of high energy transients lasting several hours. Their exact nature is still elusive, and several models have been proposed to explain them. Because of the limited coverage of wide field gamma-ray detectors, the ... More
Calculating the chiral condensate of QCD at infinite coupling using a generalised lattice diagrammatic approachOct 02 2014We develop a lattice diagrammatic technique for calculating the chiral condensate of QCD at infinite coupling inspired by recent work of Tomboulis and earlier work from the 80's. The technique involves calculating the contribution of gauge link diagrams ... More
Natural Language Interaction with Explainable AI ModelsMar 13 2019This paper presents an explainable AI (XAI) system that provides explanations for its predictions. The system consists of two key components -- namely, the prediction And-Or graph (AOG) model for recognizing and localizing concepts of interest in input ... More
Smash Products of Calabi-Yau Algebras by Hopf AlgebrasDec 03 2015Given a Hopf algebra H and an H-module differential graded (dg) algebra A, this text investigates the smash product A#H from the viewpoint of Calabi-Yau duality. First it proves that all Hopf algebras with Van den Bergh duality have invertible antipode. ... More
Well-posedness of the equations of a viscoelastic fluid with a free boundaryNov 14 2009In this article, we prove the local well-posedness, for arbitrary initial data with certain regularity assumptions, of the equations of a Viscoelastic Fluid of Johnson-Segalman type with a free surface. More general constitutive laws can be easily managed ... More
Manifolds with analytic cornersMay 19 2016Manifolds with boundary and with corners form categories ${\bf Man}\subset{\bf Man^b}\subset{\bf Man^c}$. A manifold with corners $X$ has two notions of tangent bundle: the tangent bundle $TX$, and the b-tangent bundle ${}^bTX$. The usual definition of ... More
Phenotyping using Structured Collective Matrix Factorization of Multi--source EHR DataSep 14 2016The increased availability of electronic health records (EHRs) have spearheaded the initiative for precision medicine using data driven approaches. Essential to this effort is the ability to identify patients with certain medical conditions of interest ... More
On maximal diagonalizable Lie subalgebras of the first Hochschild cohomologyJan 10 2007Mar 27 2009Let A be a basic connected finite dimensional algebra over an algebraically closed field k and with ordinary quiver Q without oriented cycle. To any presentation of A by quiver and admissible relations, Martinez-Villa and de La Pena have associated the ... More
Simple connectedness of quasitilted algebrasMay 03 2007Let A be a basic connected finite dimensional algebra over an algebraically closed field. Assuming that A is quasitilted, we prove that A is simply connected if and only if its first Hochschild cohomology group HH^1(A) vanishes. This generalises a result ... More
Smash Products of Calabi-Yau Algebras by Hopf AlgebrasDec 03 2015Oct 26 2016Given a Hopf algebra H and an H-module differential graded (dg) algebra A, this article investigates the smash product A#H in terms of Calabi-Yau duality. First it proves that all Hopf algebras with Van den Bergh duality have invertible antipode. Next ... More
Topological invariants of piecewise hereditary algebrasFeb 15 2007Feb 26 2009We investigate the Galois coverings of piecewise algebras and more particularly their behaviour under derived equivalences. Under a technical assumption which is satisfied if the algebra is derived equivalent to a hereditary algebra, we prove that there ... More
Galois coverings of weakly shod algebrasSep 30 2008Mar 27 2009We investigate the Galois coverings of weakly shod algebras. For a weakly shod algebra not quasi-tilted of canonical type, we establish a correspondence between its Galois coverings and the Galois coverings of its connecting component. As a consequence, ... More
Crossed-products of Calabi-Yau algebras by finite groupsJun 06 2010May 02 2018Let a finite group G act on a differential graded algebra A. This article presents necessary conditions and sufficient conditions for the skew group algebra A*G to be Calabi-Yau. In particular, when A is the Ginzburg dg algebra of a quiver with an invariant ... More
Conjectures on counting associative 3-folds in $G_2$-manifoldsOct 31 2016There is a strong analogy between compact, torsion-free $G_2$-manifolds $(X,\varphi,*\varphi)$ and Calabi-Yau 3-folds $(Y,J,g,\omega)$. We can also generalize $(X,\varphi,*\varphi)$ to 'tamed almost $G_2$-manifolds' $(X,\varphi,\psi)$, where we compare ... More
The universal cover of a monomial triangular algebra without multiple arrowsJan 10 2007Mar 06 2008Let A be a basic connected finite dimensional algebra over an algebraically closed field k. Assuming that A is monomial and that the ordinary quiver Q of A has no oriented cycle and no multiple arrows, we prove that A admits a universal cover with group ... More
On Galois coverings and tilting modulesSep 22 2006Jan 12 2007Let A be a basic connected finite dimensional algebra over an algebraically closed field, let G be a group, let T be a basic tilting A-module and let B the endomorphism algebra of T. Under a hypothesis on T, we establish a correspondence between the Galois ... More
The fundamental group of a triangular algebra without double bypassesMar 15 2005Apr 11 2005Let A be a basic connected finite dimensional algebra over a field k and let Q be the ordinary quiver of A. To any presentation of A with Q and admissible relations, R. Martinez-Villa and J. A. de La Pena have associated a group called the fundamental ... More
On the Morita Reduced Versions of Skew Group Algebras of Path AlgebrasOct 30 2018Let R be the skew group algebra of a finite group acting on the path algebra of a quiver. This article develops both theoretical and practical methods to do computations in the Morita reduced algebra associated to R. Reiten and Riedtmann proved that there ... More
Electroweak Baryogenesis without the Phase TransitionSep 11 1997Radiation domination at the electroweak epoch is a simplifying assumption, but one for which there is no observational basis. Treating the expansion rate as a variable, I re-examine electroweak baryogenesis in various scenarios. At a first order phase ... More
Cosmological simulations of structure formation and the Vlasov equationMay 11 2008In cosmology numerical simulations of structure formation are now of central importance, as they are the sole instrument for providing detailed predictions of current cosmological models for a whole class of important constraining observations. These ... More
Kuranishi spaces as a 2-categoryOct 26 2015This is a survey of the author's in-progress book arXiv:1409.6908. 'Kuranishi spaces' were introduced in the work of Fukaya, Oh, Ohta and Ono in symplectic geometry (see e.g. arXiv:1503.07631), as the geometric structure on moduli spaces of $J$-holomorphic ... More
A new definition of Kuranishi spaceSep 24 2014Oct 27 2015'Kuranishi spaces' were introduced in the work of Fukaya, Oh, Ohta and Ono in symplectic geometry (see e.g. arXiv:1106.4882), as the geometric structure on moduli spaces of $J$-holomorphic curves. An alternative to Kuranishi spaces is the 'polyfolds' ... More
Infinite self-gravitating systems and cosmological structure formationMay 09 2008The usual thermodynamic limit for systems of classical self-gravitating point particles becomes well defined, as a {\it dynamical} problem, using a simple physical prescription for the calculation of the force, equivalent to the so-called ``Jeans' swindle''. ... More
Electroweak Baryogenesis and the Expansion Rate of the UniverseJun 04 1996Nov 25 1996The standard requirement for the production of baryons at the electroweak phase transition, that the phase transition be first order and the sphaleron bound be satisfied, is predicated on the assumption of a radiation dominated universe at that epoch. ... More
A Note on Spontaneous BaryogenesisJun 21 1994The original calculation of `spontaneous' baryogenesis overlooked the role played by transport of particles onto the bubbles wall. For typical `adiabatic' wall thicknesses and velocities one can model the problem in a fluid approximation and the mechanism ... More
2-D and 3-D Models of Convective Turbulence and Oscillations in Intermediate-Mass Main-Sequence StarsMay 14 2016We present multidimensional modeling of convection and oscillations in main-sequence stars somewhat more massive than the Sun, using three separate approaches: 1) Using the 3-D planar StellarBox radiation hydrodynamics code to model the envelope convection ... More
Central limit theorems for random polytopes in a smooth convex setMar 24 2005Let $K$ be a smooth convex set with volume one in $\BBR^d$. Choose $n$ random points in $K$ independently according to the uniform distribution. The convex hull of these points, denoted by $K_n$, is called a {\it random polytope}. We prove that several ... More
A Parallel-pulling Protocol for Free-Energy EvaluationMay 24 2011Feb 14 2012Jarzynski's equality (JE) allows us to compute free energy differences from distributions of work. In molecular dynamics simulations, the traditional way of constructing work distributions is to perform as many pulling simulations as possible. But reliable ... More
Singular vectors under random perturbationApr 12 2010Computing the first few singular vectors of a large matrix is a problem that frequently comes up in statistics and numerical analysis. Given the presence of noise, exact calculation is hard to achieve, and the following problem is of importance: \vskip2mm ... More
Integrated Silicon Photonic Transmitter for Polarization-Encoded Quantum Key DistributionJun 14 2016We present a silicon optical transmitter for polarization-encoded quantum key distribution (QKD). The chip was fabricated in a standard silicon photonic foundry process and integrated a pulse generator, intensity modulator, variable optical attenuator, ... More
A number theoretic question arising in the geometry of plane curves and in billiard dynamicsMar 25 2011We prove that if $\rho\neq1/2$ is a rational number between zero and one, then there is no integer $n>1$ such that $$ n\tan(\pi\rho)=\tan(n\pi\rho). $$ This has interpretations both in the theory of bicycle curves and that of mathematical billiards.
A structural approach to subset-sum problemsApr 20 2008We discuss a structural approach to subset-sum problems in additive combinatorics. The core of this approach are Freiman-type structural theorems, many of which will be presented through the paper. These results have applications in various areas, such ... More
Manifest Duality for Partially Massless Higher SpinsAug 15 2016Sep 16 2016In four dimensions, partially massless fields of all spins and depths possess a duality invariance akin to electric-magnetic duality. We construct metric-like gauge invariant curvature tensors for partially massless fields of all integer spins and depths, ... More
Turning Around the Sphaleron Bound: Electroweak Baryogenesis in an Alternative Post-inflationary CosmologySep 11 1997Sep 13 1997The usual sphaleron bound and the statement of the impossibility of baryon production at a second order phase transition or analytic cross-over are reformulated in the first part of the paper as requirements of the expansion rate of the Universe at the ... More
A theory of generalized Donaldson-Thomas invariants. II. Multiplicative identities for Behrend functionsJan 19 2009Jun 02 2009This paper has been withdrawn, not because of any errors (that we know of), but because rather than presenting our material as a series of 3 papers, as we originally intended, we have now combined them into one long paper, which is "A theory of generalized ... More
Mathematical modeling of antigenicity for HIV dynamicsOct 16 2008Feb 01 2011This contribution is devoted to a new model of HIV multiplication motivated by the patent of one of the authors. We take into account the antigenic diversity through what we define "antigenicity", whether of the virus or of the adapted lymphocytes. We ... More
Covering techniques for Auslander-Reiten theoryNov 30 2014Given a finite dimensional algebra over a perfect field the text introduces covering functors over the mesh category of any modulated Auslander-Reiten component of the algebra. This is applied to study the composition of irreducible morphisms between ... More
Virtual fundamental classes for moduli spaces of sheaves on Calabi-Yau four-foldsApr 02 2015Let $({\bf X},\omega_{\bf X}^*)$ be a separated, $-2$-shifted symplectic derived $\mathbb C$-scheme, in the sense of Pantev, Toen, Vezzosi and Vaquie arXiv:1111.3209, of complex virtual dimension ${\rm vdim}_{\mathbb C}{\bf X}=n\in\mathbb Z$, and $X_{\rm ... More
Quantification of discreteness effects in cosmological N-body simulations: II. Evolution up to shell crossingApr 27 2007Sep 25 2007We apply a recently developed perturbative formalism which describes the evolution under their self-gravity of particles displaced from a perfect lattice to quantify precisely, up to shell crossing, the effects of discreteness in dissipationless cosmological ... More
Quasi-stationary states in the self-gravitating sheet modelDec 22 2010Jun 29 2011We study quasi-stationary states (QSS) resulting from violent relaxation in the one-dimensional self-gravitating "sheet model", revisiting in particular the question of the adequacy of the theory of Lynden-Bell (LB) to describe them. For "waterbag" initial ... More
Gravitational force in an infinite one-dimensional Poisson distributionSep 28 2009Feb 22 2010We consider the statistical properties of the gravitational field F in an infinite one-dimensional homogeneous Poisson distribution of particles, using an exponential cut-off of the pair interaction to control and study the divergences which arise. Deriving ... More
Two-point correlation properties of stochastic "cloud processes''Nov 02 2007We study how the two-point density correlation properties of a point particle distribution are modified when each particle is divided, by a stochastic process, into an equal number of identical "daughter" particles. We consider generically that there ... More
Canonical orientations for moduli spaces of $G_2$-instantons with gauge group SU(m) or U(m)Nov 06 2018Suppose $(X, g)$ is a compact, spin Riemannian 7-manifold, with Dirac operator $D$. Let $G$ be SU$(m)$ or U$(m)$, and $E\to X$ be a rank $m$ complex bundle with $G$-structure. Write ${\mathcal B}_E$ for the infinite-dimensional moduli space of connections ... More
Virtual fundamental classes for moduli spaces of sheaves on Calabi-Yau four-foldsApr 02 2015Nov 24 2016Let $({\bf X},\omega_{\bf X}^*)$ be a separated, $-2$-shifted symplectic derived $\mathbb C$-scheme, in the sense of Pantev, Toen, Vezzosi and Vaquie arXiv:1111.3209, of complex virtual dimension ${\rm vdim}_{\mathbb C}{\bf X}=n\in\mathbb Z$, and $X_{\rm ... More
Non-Gaussian Shape Discrimination with Spectroscopic Galaxy SurveysSep 18 2014Oct 02 2014[Abridged] We consider how galaxy clustering data, from Mpc to Gpc scales, from upcoming large scale structure surveys, such as Euclid and DESI, can provide discriminating information about the bispectrum shape arising from a variety of inflationary scenarios. ... More
Relaxation to thermal equilibrium in the self-gravitating sheet modelApr 13 2010Nov 02 2010We revisit the issue of relaxation to thermal equilibrium in the so-called "sheet model", i.e., particles in one dimension interacting by attractive forces independent of their separation. We show that this relaxation may be very clearly detected and ... More
Baryogenesis from `electrogenesis' in a scalar field dominated epochMar 20 2000Scalar fields can play a dominant role in the dynamics of the Universe until shortly before nucleosynthesis. Examples are provided by domination by a kinetic mode of a scalar field, which may be both the inflaton and the late time `quintessence', and ... More
Strong Coupling Problem with Time-Varying Sound SpeedJul 18 2011Sep 02 2011For a single scalar field with unit sound speed minimally coupled to Einstein gravity, there are exactly three distinct cosmological solutions which produce a scale invariant spectrum of curvature perturbations in a dynamical attractor background, assuming ... More
Bekenstein entropy bound for weakly-coupled field theories on a 3-sphereMar 06 2012Jun 13 2012We calculate the high temperature partition functions for SU(Nc) or U(Nc) gauge theories in the deconfined phase on S^1 x S^3, with scalars, vectors, and/or fermions in an arbitrary representation, at zero 't Hooft coupling and large Nc, using analytical ... More
Immersed Lagrangian Floer TheoryMar 05 2008Let (M,w) be a compact symplectic manifold, and L a compact, embedded Lagrangian submanifold in M. Fukaya, Oh, Ohta and Ono construct Lagrangian Floer cohomology for such M,L, yielding groups HF^*(L,b;\Lambda) for one Lagrangian or HF^*((L,b),(L',b');\Lambda) ... More
Natural Associativity without the Pentagon conditionSep 14 2001Jun 25 2003A premonoidal category is equipped only with a bifunctor and a natural isomorphism for associativity. We introduce a (deformation) natural automorphism representing the deviation from the Pentagon condition. We uncover a binary tree representation for ... More
Automated alignment of a reconfigurable optical system using focal-plane sensing and Kalman filteringAug 26 2016Automation of alignment tasks can provide improved efficiency and greatly increase the flexibility of an optical system. Current optical systems with automated alignment capabilities are typically designed to include a dedicated wavefront sensor. Here, ... More
Quantification of discreteness effects in cosmological N-body simulations: I. Initial ConditionsOct 19 2004Apr 28 2007The relation between the results of cosmological N-body simulations, and the continuum theoretical models they simulate, is currently not understood in a way which allows a quantification of N dependent effects. In this first of a series of papers on ... More
Family Symmetry, Fermion Mass Matrices and Cosmic TextureJan 27 1993The observed replication of fermions in three families is undoubtedly a reflection of a deeper symmetry underlying the standard model. In this paper we investigate one very elementary possibility, that physics above the grand unification scale is described ... More
Non-linear gravitational clustering of cold matter in an expanding universe: indications from 1D toy modelsDec 07 2010Mar 02 2011Studies of a class of infinite one dimensional self-gravitating systems have highlighted that, on the one hand, the spatial clustering which develops may have scale invariant (fractal) properties, and, on the other, that they display "self-similar" properties ... More
Primordial Magnetic Fields, Right Electrons, and the Abelian AnomalyFeb 28 1997Jul 17 1997In the standard model there are charges with abelian anomaly only (e.g. right-handed electron number) which are effectively conserved in the early universe until some time shortly before the electroweak scale. A state at finite chemical potential of such ... More
Investigating the Consistency of Stellar Evolution Models with Globular Cluster Observations via the Red Giant Branch BumpOct 26 2015Synthetic RGBB magnitudes are generated with the most recent theoretical stellar evolution models computed with the Dartmouth Stellar Evolution Program (DSEP) code. They are compared to the observational work of Nataf et al., who present RGBB magnitudes ... More
A theory of generalized Donaldson-Thomas invariantsOct 31 2008Jul 07 2010Let X be a Calabi-Yau 3-fold over C. The Donaldson-Thomas invariants of X are integers DT^a(t) which count stable sheaves with Chern character a on X, with respect to a Gieseker stability condition t. They are defined only for Chern characters a for which ... More
Degrees of Irreducible Morphisms over Perfect FieldsApr 12 2017May 20 2018The module category of any artin algebra is filtered by the powers of its radical, thus defining an associated graded category. As an extension of the degree of irreducible morphisms, this text introduces the degree of morphisms in the module category ... More
Unsupervised motion saliency map estimation based on optical flow inpaintingMar 12 2019The paper addresses the problem of motion saliency in videos, that is, identifying regions that undergo motion departing from its context. We propose a new unsupervised paradigm to compute motion saliency maps. The key ingredient is the flow inpainting ... More
Trends in Space Astronomy and Cosmic Vision 2015-2025Oct 28 2005As a short introduction to the astronomy session, the response of the community to the Call for Themes issued by ESA and the specific themes selected by the Astronomy Working Group are briefly presented in connection with the four grand themes finally ... More
Degrees of irreducible morphisms and finite-representation typeNov 12 2009We study the degree of irreducible morphisms in any Auslander-Reiten component of a finite dimensional algebra over an algebraically closed field. We give a characterization for an irreducible morphism to have finite left (or right) degree. This is used ... More