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Results for "Esteban Vazquez-Fernandez"

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Three-dimensional Lorentzian homogeneous Ricci solitonsNov 06 2009We describe three-dimensional Lorentzian homogeneous Ricci solitons, showing that all types (i.e. shrinking, expanding and steady) exist. Moreover, all non-trivial examples have non-diagonalizable Ricci operator with one only eigenvalue.
Neutrinos in physics and astrophysicsOct 18 1999An elementary general overview of the neutrino physics and astrophysics is given. We start by a historical account of the development of our understanding of neutrinos and how they helped to unravel the structure of the Standard Model. We discuss why ... More
Electron neutrino opacity in magnetised mediaNov 03 1997We study the effects of strong magnetic fields ($B> 10^{13}$~G) in the cross section for $\nu_e n\to p e$ scattering in the presence of a degenerate electron background. This can be relevant for the $\nu_e$ propagation in the proto-neutron star stage ... More
Internal Fluctuations Effects on Fisher WavesMay 02 2001May 03 2001We study the diffusion-limited reaction A + A <-> A in different spatial dimensions to observe the effect of internal fluctuations on the interface between stable and unstable phases. We find that, similar to what has been observed in d=1 dimensions, ... More
A hydrodynamic approach to boost invariant free streamingFeb 21 2014Aug 10 2015We consider a family of exact boost invariant solutions of the transport equation for free streaming massless particles, where the one particle distribution function is defi?ned in terms of a function of a single variable. The evolution of second and ... More
Non abelian hydrodynamics and heavy ion collisionsNov 07 2013The goal of the relativistic heavy ion collisions (RHIC) program is to create a state of matter where color degrees of freedom are deconfined. The dynamics of matter in this state, in spite of the complexities of quantum chromodynamics, is largely determined ... More
An extension of the momentum transfer model to time-dependent pipe turbulenceSep 20 2011Jan 10 2012We analyze a possible extension of Gioia and Chakraborty's momentum transfer model of friction in steady turbulent pipe flows (Phys. Rev. Lett. 96, 044502 (2006)) to the case of time and/or space dependent turbulent flows. The end result is an expression ... More
Friction factor for turbulent flow in rough pipes from Heisenberg's closure hypothesisJan 02 2009Apr 17 2009We show that the main results of the analysis of the friction factor for turbulent pipe flow reported in G. Gioia and P. Chakraborty (GC), Phys. Rev. Lett. 96, 044502 (1996) can be recovered by assuming the Heisenberg closure hypothesis for the turbulent ... More
Collapse times for attractive Bose-Einstein condensatesAug 24 2007Oct 25 2007We argue that the main mechanism for condensate collapse in an attractive Bose-Einstein condensate is the loss of coherence between atoms a finite distance apart, rather than the growth of the occupation number in noncondensate modes. Since the former ... More
Noise induced inflationNov 19 1998We consider a closed Friedmann-Robertson-Walker Universe driven by the back reaction from a massless, non-conformally coupled quantum scalar field. We show that the back-reaction of the quantum field is able to drive the cosmological scale factor over ... More
Relativistic fluctuating hydrodynamicsAug 20 1997Nov 18 1997We derive the formulae of fluctuating hydrodynamics appropiate to a relativistically consistent divergence type theory, obtaining Landau - Lifshitz fluctuating hydrodynamics as a limiting case.
Neutrino PhenomenologyDec 27 2004A general overview of neutrino physics is given, starting with a historical account of the development of our understanding of neutrinos and how they helped to unravel the structure of the Standard Model. We discuss why it is so important to establish ... More
Microlensing searches of dark matterApr 25 2000The evolution of the observational results of microlensing towards the LMC and some of the suggested interpretations to account for them are discussed. It is emphasized that the results at present are indicative of a lensing population of white dwarfs, ... More
Numerical schemes for continuum models of reaction-diffusion systems subject to internal noiseApr 26 2004Aug 06 2004We present new numerical schemes to integrate stochastic partial differential equations which describe the spatio-temporal dynamics of reaction-diffusion (RD) problems under the effect of internal fluctuations. The schemes conserve the nonnegativity of ... More
Generalized Presentation Attack Detection: a face anti-spoofing evaluation proposalApr 12 2019Over the past few years, Presentation Attack Detection (PAD) has become a fundamental part of facial recognition systems. Although much effort has been devoted to anti-spoofing research, generalization in real scenarios remains a challenge. In this paper ... More
Studies of Inclusive Jet Production in ep Interactions at HERAAug 15 2003Inclusive jet production in neutral and charged current deep inelastic scattering, in photoproduction and the transition region has been studied with the ZEUS and H1 detectors at HERA. The measurements have been compared to next-to-leading-order QCD calculations ... More
Exotic hadronic states at HERANov 12 2004Recent results from H1, ZEUS, HERMES and HERA-B on searches for exotic baryons in ep collisions, eD scattering and pA scattering at HERA are reviewed. Evidence for the production of the strange pentaquark Theta^+ and of a narrow anti-charmed baryon decaying ... More
A Hydrodynamic Approach to the Study of Anisotropic Instabilities in Dissipative Relativistic PlasmasFeb 04 2016Sep 29 2016We develop a purely hydrodynamic formalism to describe collisional, anisotropic instabilities in a relativistic plasma, that are usually described with kinetic theory tools. Our main motivation is the fact that coarse-grained models of high particle number ... More
Noise Effects on Synchronized Globally Coupled OscillatorsFeb 27 1998The synchronized phase of globally coupled nonlinear oscillators subject to noise fluctuations is studied by means of a new analytical approach able to tackle general couplings, nonlinearities, and noise temporal correlations. Our results show that the ... More
Selecting interesting zones at Aburrá valley and valley of St. Nicholas Valley's using the identification method of Density-based Clustering and Improved Nearest Neighbor applied on social networksJun 09 2014More than ever, social networks have become an important place in the interaction and behaviour of humans in the last decade. This valuable position, makes it imperative analyze different aspects of everyday life and science in general. In this article ... More
Neutrino MassesDec 12 1994This is a review for Reports of Progress in Physics. After an introduction we start by explaining the different neutrino masses corresponding to different types of neutrinos, Dirac or Majorana, in section 2. In section 3 we discuss the main elementary ... More
Lagrangian Grassmannian in Infinite DimensionAug 16 2008Given a complex structure $J$ on a real (finite or infinite dimensional) Hilbert space $H$, we study the geometry of the Lagrangian Grassmannian $\Lambda(H)$ of $H$, i.e. the set of closed linear subspaces $L\subset H$ such that $$J(L)=L^\perp.$$ The ... More
Spectral properties of Landau Hamiltonians with non-local potentialsJan 14 2019We consider the Landau Hamiltonian $H_0$, self-adjoint in $L^2({\mathbb R}^2)$, whose spectrum consists of an arithmetic progression of infinitely degenerate positive eigenvalues $\Lambda_q$, $q \in {\mathbb Z}_+$. We perturb $H_0$ by a non-local potential ... More
Nonsingular cosmological modelsMay 26 2011A short introduction to cosmological models that go from an era of accelerated collapse to an expanding era without displaying a singularity is presented.
The rectifiable distance in the unitary Fredholm groupDec 24 2008Let $U_c(H)={u: u is unitary and u-1 is compact}$ stand for the unitary Fredholm group. We prove the following convexity result. Denote by $d_\infty$ the rectifiable distance induced by the Finsler metric given by the operator norm in $U_c(H)$. If $u_0,u_1,u\in ... More
Hopf-Rinow Theorem in the Sato GrassmannianAug 19 2008Let $U_2({\cal H})$ be the Banach-Lie group of unitary operators in the Hilbert space ${\cal H}$ which are Hilbert-Schmidt perturbations of the identity 1. In this paper we study the geometry of the unitary orbit $$\{upu^*: u\in U_2({\cal H})\},$$ of ... More
Non-negativity preserving numerical algorithms for stochastic differential equationsSep 30 2005Construction of splitting-step methods and properties of related non-negativity and boundary preserving numerical algorithms for solving stochastic differential equations (SDEs) of Ito-type are discussed. We present convergence proofs for a newly designed ... More
Weak Riemannian manifolds from finite index subfactorsAug 19 2008Let $N\subset M$ be a finite Jones' index inclusion of II$_1$ factors, and denote by $U_N\subset U_M$ their unitary groups. In this paper we study the homogeneous space $U_M/U_N$, which is a (infinite dimensional) differentiable manifold, diffeomorphic ... More
Homotopy of vector statesAug 17 2000Let $B$ be a C$^*$-algebra and $X$ a C$^*$ Hilbert $B$-module. If $p\in B$ is a projection, denote by $S_p =\{x\in X : < x,x> =p\}$, the $p$-sphere of $X$. For $\phi$ a state of $B$ with support $p$ in $B$ and $x\in S_p$, consider the state $\phi_x$ of ... More
Defect formation in the Swift-Hohenberg equationFeb 01 2003We study numerically and analytically the dynamics of defect formation during a finite-time quench of the two dimensional Swift-Hohenberg (SH) model of Rayleigh-Benard convection. We find that the Kibble-Zurek picture of defect formation can be applied ... More
Modeling sexual selection in Túngara frog and rationality of mate choiceOct 13 2016The males of the specie of frogs Engystomops pustulosus produce simple and com- plex calls to lure females, as a way of Intersexual selection. Complex calls lead males to a greater reproductive success than simple calls do. However, the complex calls ... More
Direct Observation of Transverse and Vortex Metastable Magnetic Domains observed in Cylindrical NanowiresMay 12 2017We present experimental evidence of metastable magnetic domains in cylindrical CoNi nanowires. Transverse (perpendicular) domains have been previously observed only in flat nanostrips. Here they are found together with more conventional vortex domains ... More
Affinity Paths and Information Diffusion in Social NetworksMay 17 2011Widespread interest in the diffusion of information through social networks has produced a large number of Social Dynamics models. A majority of them use theoretical hypothesis to explain their diffusion mechanisms while the few empirically based ones ... More
Self-adjointness of Dirac operators via Hardy-Dirac inequalitiesJun 09 2007Distinguished selfadjoint extensions of Dirac operators are constructed for a class of potentials including Coulombic ones up to the critical case, $-|x|^{-1}$. The method uses Hardy-Dirac inequalities and quadratic form techniques.
A data-driven linear-programming methodology for optimal transportOct 09 2017A data-driven formulation of the optimal transport problem is presented and solved using adaptively refined meshes to decompose the problem into a sequence of finite linear programming problems. Both the marginal distributions and their unknown optimal ... More
Small-spatial scale variations of nebular properties and the abundance discrepancy in three Galactic HII regionsMar 12 2010We present results of long-slit spectroscopy in several slit positions that cover different morphological structures of the central parts of three bright Galactic HII regions: M8, M17 and NGC7635. We study the spatial distributions of a large number of ... More
The abundance discrepancy problem in HII regionsOct 30 2006The origin of the abundance discrepancy in nebulae is one of the key problems in the physics of photoionized nebulae. In this work we have analized a sample of Galactic and extragalactic H II regions where the abundance discrepancy have been measured, ... More
About existence, symmetry and symmetry breaking for extremal functions of some interpolation functional inequalitiesNov 24 2010This article is devoted to a review of some recent results on existence, symmetry and symmetry breaking of optimal functions for Caffarelli-Kohn-Nirenberg (CKN) and weighted logarithmic Hardy (WLH) inequalities. These results have been obtained in a series ... More
Results from DELPHI on the searches for SM and MSSM Neutral Higgs bosonsJul 01 2003These final results from DELPHI searches for the Standard Model SM Higgs boson, together with benchmark scans of the Minimal Supersymmetric Standard Model MSSM neutral Higgs bosons, used data taken at centre-of-mass energies between 200 and 209GeV with ... More
The Lerch zeta function as a fractional derivativeApr 21 2018We derive and prove a new formulation of the Lerch zeta function as a fractional derivative of an elementary function. We demonstrate how this formulation interacts very naturally with basic known properties of Lerch zeta, and use the functional equation ... More
Hodge structures for orbifold cohomologyNov 03 2003May 16 2006We construct a polarized Hodge structure on the primitive part of Chen and Ruan's orbifold cohomology $H_{orb}^k(X)$ for projective $SL$-orbifolds $X$ satisfying a ``Hard Lefschetz Condition''. Furthermore, the total cohomology $H_{orb}^{*,*}(X)$ forms ... More
Results on Proton-Irradiated 3D Pixel Sensors Interconnected to RD53A Readout ASICMar 29 2019Test beam results obtained with 3D pixel sensors bump-bonded to the RD53A prototype readout ASIC are reported. Sensors from FBK (Italy) and IMB-CNM (Spain) have been tested before and after proton-irradiation to an equivalent fluence of about $1$ $\times$ ... More
An elliptic regularity theorem for fractional partial differential operatorsApr 03 2018We present and prove a version of the elliptic regularity theorem for partial differential equations involving fractional Riemann-Liouville derivatives. In this case, regularity is defined in terms of Sobolev spaces $H^s(X)$: if the forcing of a linear ... More
Reconstructing 1/2 BPS Space-Time Metrics from Matrix Models and Spin ChainsDec 01 2006Using the AdS/CFT correspondence, we address the question of how to measure complicated space-time metrics using gauge theory probes. In particular, we consider the case of the 1/2 BPS geometries of type IIB supergravity. These geometries are classified ... More
Constraining Modified Gravity with Large non-GaussianitiesJun 03 2008Jun 17 2008In writing a covariant effective action for single field inflation, one is allowed to add a Gauss-Bonnet and axion-type curvature couplings. These couplings represent modifications of gravity, and are the unique higher-curvature terms that lead to second ... More
Black Hole Production from High Energy Scattering in AdS/CFTSep 21 2007In this article we show how to set up initial states in ${\cal N} =4$ SYM theory that correspond to high energy graviton collisions, leading to black hole formation in $AdS_5\times S^5$. For this purpose, we study states in the gauge theory that are dual ... More
BPS Condensates, Matrix Models and Emergent String TheoryJul 25 2006Sep 28 2006A prescription is given for computing anomalous dimensions of single trace operators in SYM at strong coupling and large $N$ using a reduced model of matrix quantum mechanics. The method involves treating some parts of the operators as "BPS condensates" ... More
Scale Invariance, Bounded Rationality and Non-Equilibrium EconomicsFeb 23 2009We study a class of heterogeneous agent-based models which are based on a basic set of principles, and the most fundamental operations of an economic system: trade and product transformations. A basic guiding principle is scale invariance, which means ... More
Isoparametric foliations on complex projective spacesApr 16 2012Mar 03 2014Irreducible isoparametric foliations of arbitrary codimension q on complex projective spaces CP^n are classified, except if n=15 and q=1. Remarkably, there are noncongruent examples that pull back under the Hopf map to congruent foliations on the sphere. ... More
Fundamental solution and long time behaviour of the Porous Medium Equation in Hyperbolic SpaceAug 24 2014Sep 28 2014We construct the fundamental solution of the Porous Medium Equation posed in the hyperbolic space $H^n$ and describe its asymptotic behaviour as $t\to\infty$. We also show that it describes the long time behaviour of integrable nonnegative solutions, ... More
Barenblatt solutions and asymptotic behaviour for a nonlinear fractional heat equation of porous medium typeMay 29 2012Sep 13 2012We establish the existence and uniqueness of fundamental solutions for the fractional porous medium equation introduced in \cite{PQRV1}. They are self-similar functions of the form $u(x,t)= t^{-\alpha} f(|x|\,t^{-\beta})$ with suitable $\alpha$ and $\beta$. ... More
A new integral loss function for Bayesian optimizationAug 20 2014We consider the problem of maximizing a real-valued continuous function $f$ using a Bayesian approach. Since the early work of Jonas Mockus and Antanas \v{Z}ilinskas in the 70's, the problem of optimization is usually formulated by considering the loss ... More
Physical Processes of Interstellar TurbulenceFeb 20 2012I discuss the role of self-gravity and radiative heating and cooling in shaping the nature of the turbulence in the interstellar medium (ISM) of our galaxy. The heating and cooling cause it to be highly compressible, and, in some regimes of density and ... More
Intensity of gluon bremsstrahlung in a finite plasmaNov 05 2018The intensity of single gluon bremsstrahlung in a QCD plasma is evaluated with a Monte Carlo which solves the transport equation for a generic interaction with the medium. In particular the calculation is performed for a Debye screened potential and compared ... More
On the usefulness of persistent excitation in ARX adaptive trackingMar 14 2009The usefulness of persistent excitation is well-known in the control community. Thanks to a persistently excited adaptive tracking control, we show that it is possible to avoid the strong controllability assumption recently proposed in the multidimensional ... More
Existence of maximal solutions for some very singular nonlinear fractional diffusion equations in 1DMay 19 2015We consider nonlinear parabolic equations involving fractional diffusion of the form $\partial_t u + (-\Delta)^s \Phi(u)= 0,$ with $0<s<1$, and solve an open problem concerning the existence of solutions for very singular nonlinearities $\Phi$ in power ... More
The Air Microwave Yield (AMY) experiment - A laboratory measurement of the microwave emission from extensive air showersOct 17 2013The AMY experiment aims to measure the microwave bremsstrahlung radiation (MBR) emitted by air-showers secondary electrons accelerating in collisions with neutral molecules of the atmosphere. The measurements are performed using a beam of 510 MeV electrons ... More
Finite-Time and -Size Scalings in the Evaluation of Large Deviation Functions - Part I: Analytical Study using a Birth-Death ProcessJul 16 2016Aug 01 2016The Giardin\`a-Kurchan-Peliti algorithm is a numerical procedure that uses population dynamics in order to calculate large deviation functions associated to the distribution of time-averaged observables. To study the numerical errors of this algorithm, ... More
Rigidity versus symmetry breaking via nonlinear flows on cylinders and Euclidean spacesJun 11 2015This paper is motivated by the characterization of the optimal symmetry breaking region in Caffarelli-Kohn-Nirenberg inequalities. As a consequence, optimal functions and sharp constants are computed in the symmetry region. The result solves a longstanding ... More
Keller-Lieb-Thirring inequalities for Schrödinger operators on cylindersMar 30 2015Jun 11 2015This note is devoted to Keller-Lieb-Thirring spectral estimates for Schr\"odinger operators on infinite cylinders: the absolute value of the ground state level is bounded by a function of a norm of the potential. Optimal potentials with small norms are ... More
Domains for Dirac-Coulomb min-max levelsFeb 16 2017Apr 17 2018We consider a Dirac operator in three space dimensions, with an electrostatic (i.e. real-valued) potential $V(x)$, having a strong Coulomb-type singularity at the origin. This operator is not always essentially self-adjoint but admits a distinguished ... More
On the Relativistic Invariance of EntanglementSep 27 2011In this work we study the entanglement properties under a Lorentz boost of a pair of spin- 1 massive particles, with spin and momentum as the sole degrees of freedom of the system. Different cases for entanglement between spins and momenta are considered ... More
Finite-Time and -Size Scalings in the Evaluation of Large Deviation Functions - Part II: Numerical Approach in Continuous TimeJul 29 2016Rare trajectories of stochastic systems are important to understand -- because of their potential impact. However, their properties are by definition difficult to sample directly. Population dynamics provide a numerical tool allowing their study, by means ... More
Recent results from the Pierre Auger ObservatorySep 12 2008The main results from the Auger Observatory are described. A steepening of the spectrum is observed at the highest energies, supporting the expectation that above $4\times 10^{19}$ eV the cosmic ray energies are significantly degraded by interactions ... More
Cosmic ray photodisintegration and the knee of the spectrumNov 01 2000Jun 26 2001We explore in some detail the scenario proposed to explain the observed knee of the cosmic ray (CR) spectrum as due to the effects of photodisintegration of the CR nuclei by interactions with optical and soft UV photons in the source region. We show that ... More
Finite-Time and -Size Scalings in the Evaluation of Large Deviation Functions - Part I: Analytical Study using a Birth-Death ProcessJul 16 2016Oct 25 2016The Giardin\`a-Kurchan-Peliti algorithm is a numerical procedure that uses population dynamics in order to calculate large deviation functions associated to the distribution of time-averaged observables. To study the numerical errors of this algorithm, ... More
Finite-Time and -Size Scalings in the Evaluation of Large Deviation Functions - Part II: Numerical Approach in Continuous TimeJul 29 2016Oct 25 2016Rare trajectories of stochastic systems are important to understand -- because of their potential impact. However, their properties are by definition difficult to sample directly. Population dynamics provide a numerical tool allowing their study, by means ... More
Eigenvalues for radially symmetric non-variational fully nonlinear operatorsAug 07 2009In this paper we present an elementary theory about the existence of eigenvalues for fully nonlinear radially symmetric 1-homogeneous operators. A general theory for first eigenvalues and eigenfunctions of 1-homogeneous fully nonlinear operators exists ... More
$L^γ$-PageRank for Semi-Supervised LearningMar 11 2019PageRank for Semi-Supervised Learning has shown to leverage data structures and limited tagged examples to yield meaningful classification. Despite successes, classification performance can still be improved, particularly in cases of fuzzy graphs or unbalanced ... More
Balanced modular parameterizationsMay 27 2014For prime levels $5 \le p \le 19$, sets of $\Gamma_{0}(p)$-permuted theta quotients are constructed that generate the graded rings of modular forms of positive integer weight for $\Gamma_{1}(p)$. An explicit formulation of the permutation representation ... More
Canonical sphere bundles of the Grassmann manifoldMar 02 2018For a given Hilbert space $\mathcal H$, consider the space of self-adjoint projections $\mathcal P(\mathcal H)$. In this paper we study the differentiable structure of a canonical sphere bundle over $\mathcal P(\mathcal H)$ given by $$ \mathcal R=\{\, ... More
Turbulent diffusion and drift in galactic magnetic fields and the explanation of the knee in the cosmic ray spectrumJun 19 2002Dec 17 2002We reconsider the scenario in which the knee in the cosmic ray spectrum is explained as due to a change in the escape mechanism of cosmic rays from the Galaxy from one dominated by transverse diffusion to one dominated by drifts. We solve the diffusion ... More
Roughening and superroughening in the ordered and random two-dimensional sine-Gordon modelsMar 10 2000Jun 05 2000We present a comparative numerical study of the ordered and the random two-dimensional sine-Gordon models on a lattice. We analytically compute the main features of the expected high temperature phase of both models, described by the Edwards-Wilkinson ... More
Effective metric in nonlinear scalar field theoriesAug 16 2011We discuss several features of the propagation of perturbations in nonlinear scalar field theories using the effective metric. It is shown that the effective metric can be classified according to whether the gradient of the scalar field is timelike, null, ... More
Homogeneous manifolds from noncommutative measure spacesJun 24 2009Jul 14 2009Let M be a finite von Neumann algebra with a faithful trace $\tau$. In this paper we study metric geometry of homogeneous spaces O of the unitary group U of M, endowed with a Finsler quotient metric induced by the p-norms of $\tau$, $||x||_p=\tau(|x|^p)^{1/p}$, ... More
D-brane Disformal Coupling and Thermal Dark MatterAug 23 2017Nov 03 2017Conformal and Disformal couplings between a scalar field and matter occur naturally in general scalar-tensor theories. In D-brane models of cosmology and particle physics, these couplings originate from the D-brane action describing the dynamics of its ... More
Competent hosts and endemicity of multi-host diseasesMay 26 2017Nov 27 2018In this paper we propose a method to study a general vector-hosts mathematical model in order to explain how the changes in biodiversity could influence the dynamics of vector-borne diseases. We find that under the assumption of frequency-dependent transmission, ... More
Entanglement sudden-death time: a geometric quantitySep 13 2013Jan 07 2015We study the entanglement evolution of the set of Bell diagonal states for a two-qubit system coupled to two independent vacuum noise sources. This set can be represented geometrically as the set of points inside a tetrahedron in a three-dimensional Euclidean ... More
The C*-algebra of compact perturbations of diagonal operatorsMar 14 2019We study the elementary C*-algebra whose elements are the sum of a diagonal plus a compact operator. We describe the structure of the unitary group, the sets of ideals, automorhisms and projections.
The group of L^2 isometries on H^1_0Mar 06 2012Let U be an open subset of R^n. Let L^2=L^2(U,dx) and H^1_0=H^1_0(U) be the standard Lebesgue and Sobolev spaces of complex-valued functions. The aim of this paper is to study the group G of invertible operators on H^1_0 which preserve the L^2-inner product. ... More
Exact solutions for a cosmology within the Israel-Stewart theoryDec 12 2018In this paper we find a novel exact analytic solution for a cosmology filled with a dissipative fluid, in the framework of the causal Israel-Stewart theory. We assume a bulk viscous coefficient with the dependence $\xi=\xi_{0}\rho^{1/2}$, where $\rho$ ... More
A weighted Moser-Trudinger inequality and its relation to the Caffarelli-Kohn-Nirenberg inequalities in two space dimensionsMar 29 2007We first prove a weighted inequality of Moser-Trudinger type depending on a parameter, in the two-dimensional Euclidean space. The inequality holds for radial functions if the parameter is larger than -1. Without symmetry assumption, it holds if and only ... More
Nonlinear Eigenvalues and Bifurcation Problems for Pucci's OperatorSep 17 2004In this paper we extend existing results concerning generalized eigenvalues of Pucci's extremal operators. In the radial case, we also give a complete description of their spectrum, together with an equivalent of Rabinowitz's Global Bifurcation Theorem. ... More
Localized Instabilities and Spinodal Decomposition in Driven Systems in the Presence of ElasticitySep 21 2017We study numerically and analytically the instabilities associated with phase separation in a solid layer on which an external material ux is imposed. The first instability is localized within a boundary layer at the exposed free surface by a process ... More
An Abstract Algebraic Logic View on Judgment AggregationMar 27 2016In the present paper, we propose Abstract Algebraic Logic (AAL) as a general logical framework for Judgment Aggregation. Our main contribution is a generalization of Herzberg's algebraic approach to characterization results in on judgment aggregation ... More
Symmetric ground states for a stationary relativistic mean-field model for nucleons in the nonrelativistic limitApr 29 2012Sep 06 2012In this paper we consider a model for a nucleon interacting with the $\omega$ and $\sigma$ mesons in the atomic nucleus. The model is relativistic, but we study it in the nuclear physics nonrelativistic limit, which is of a very different nature from ... More
Symmetry of extremals of functional inequalities via spectral estimates for linear operatorsSep 28 2011We prove new symmetry results for the extremals of the Caffarelli-Kohn-Nirenberg inequalities in any dimension larger or equal than 2, in a range of parameters for which no explicit results of symmetry were previously known.
Large critical exponents for some second order uniformly elliptic operatorsOct 28 2005In this paper we investigate the critical exponents of two families of Pucci's extremal operators. The notion of critical exponent that we have chosen for these fully nonlinear operators whihc are not variational is that of threshold betweeen existence ... More
Relativistic hydrogenic atoms in strong magnetic fieldsJul 02 2006In the Dirac operator framework we characterize and estimate the ground state energy of relativistic hydrogenic atoms in a constant magnetic field and describe the asymptotic regime corresponding to a large field strength using relativistic Landau levels. ... More
Integrable open spin chains from giant gravitonsJan 11 2005Jan 27 2005We prove that in the presence of a maximal giant graviton state in N=4 SYM, the states dual to open strings attached to the giant graviton give rise to an PSU(2,2|4) open spin chain model with integrable boundary conditions in the SO(6) sector of the ... More
Complex Osserman Kaehler ManifoldsMar 28 2010Let H be a 4 dimensional almost Hermitian manifold which satisfies the Kaehler identity. Then H is complex Osserman if and only if H has constant holomorphic sectional curvature. We also classify in arbitrary dimensions all the complex Osserman Kaehler ... More
The global geometry of Riemannian manifolds with commuting curvature operatorsSep 18 2006We give manifolds in both the Riemannian and in the higher signature settings whose Riemann curvature operators commute, i.e. which satisfy R(a,b)R(c,d)=R(c,d)R(a,b) for all tangent vectors. These manifolds have global geometric phenomena which are quite ... More
Impact of interactions on human dynamicsOct 25 2007Aug 05 2008Queueing theory has been recently proposed as a framework to model the heavy tailed statistics of human activity patterns. The main predictions are the existence of a power-law distribution for the interevent time of human actions and two decay exponents ... More
Recent advances on the non-coherent band surgery model for site-specific recombinationOct 20 2018Site-specific recombination is an enzymatic process where two sites of precise sequence and orientation along a circle come together, are cleaved, and the ends are recombined. Site-specific recombination on a knotted substrate produces another knot or ... More
A note on band surgery and the signature of a knotJun 06 2018Jul 12 2018Band surgery is an operation which transforms a knot or link in the three-sphere into another knot or link. We prove that if two quasi-alternating knots $K$ and $K'$ of the same square-free determinant are related by a band surgery, then the absolute ... More
Osserman and conformally Osserman manifolds with warped and twisted product structureJul 18 2008We characterize Osserman and conformally Osserman Riemannian manifolds with the local structure of a warped product. By means of this approach we analyze the twisted product structure and obtain, as a consequence, that the only Osserman manifolds which ... More
A proof of uniform convergence over time for a distributed particle filterApr 05 2015Nov 24 2015Distributed signal processing algorithms have become a hot topic during the past years. One class of algorithms that have received special attention are particles filters (PFs). However, most distributed PFs involve various heuristic or simplifying approximations ... More
Optimization of Starburst99 for Intermediate-Age and Old Stellar PopulationsDec 17 2004We have incorporated the latest release of the Padova models into the evolutionary synthesis code Starburst99. The Padova tracks were extended to include the full asymptotic giant branch (AGB) evolution until the final thermal pulse over the mass range ... More
Gauge Invariance, Geometry and ArbitrageAug 21 2009In this work, we identify the most general measure of arbitrage for any market model governed by It\^o processes. We show that our arbitrage measure is invariant under changes of num\'{e}raire and equivalent probability. Moreover, such measure has a geometrical ... More
The manipulation problem in quantum mechanicsOct 26 1998We explain the meaning of dynamical manipulation, and we illustrate its mechanism by using a system composed of a charged particle in a Penning trap. It is shown that by means of appropriate electric shocks (delta-like pulses) applied to the trap walls ... More