Results for "Felipe Pedreros Bustos"

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Remote sensing of geomagnetic fields and atomic collisions in the mesosphereFeb 09 2018Magnetic-field sensing has contributed to the formulation of the plate-tectonics theory, the discovery and mapping of underground structures on Earth, and the study of magnetism in other planets. Filling the gap between space-based and near-Earth observation, ... More
Twisted Pseudo-differential Operators on Type I Locally Compact GroupsMay 16 2016Let $\G$ be a locally compact group satisfying some technical requirements and $\wG$ its unitary dual. Using the theory of twisted crossed product $C^*$-algebras, we develop a twisted global quantization for symbols defined on $\G\times\wG$ and taking ... More
Cayley-type graphs for group-subgroup pairsJun 12 2014Nov 24 2014In this paper we introduce a Cayley-type graph for group-subgroup pairs and present some elementary properties of such graphs, including connectedness, their degree and partition structure, and vertex-transitivity. We relate these properties to those ... More
$C^*$-Algebraic Covariant StructuresJun 27 2014We introduce {\it covariant structures} $\left\{(\A,\k),(\a,\aa),\(\ha,\haa\)\right\}$ formed of a separable $C^*$-algebra $\A$, a measurable twisted action $(\a,\aa)$ of the second-countable locally compact group $\G$\,, a measurable twisted action $(\ha,\haa)$ ... More
Geometric rectification for nanoscale vibrational energy harvestingJan 29 2018Feb 06 2018In this work, we present a mechanism that, based on quantum-mechanical principles, allows one to recover kinetic energy at the nanoscale. Our premise is that very small mechanical excitations, such as those arising from sound waves propagating through ... More
The Proper Motion of the Large Magellanic Cloud: A ReanalysisJan 10 2006We have determined the proper motion (PM) of the Large Magellanic Cloud (LMC) relative to four background quasi-stellar objects, combining data from two previous studies made by our group, and new observations carried out in four epochs not included the ... More
The thermodynamic cost of driving quantum systems by their boundariesSep 14 2015Oct 22 2015The laws of thermodynamics put limits to the efficiencies of thermal machines. Analogues of these laws are now established for quantum engines weakly and passively coupled to the environment providing a framework to find improvements to their performance. ... More
Imaginary Killing Spinors in Lorenztian GeometryFeb 03 2003We study the geometric structure of Lorentzian spin manifolds, which admit imaginary Killing spinors. The discussion is based on the cone construction and a normal form classification of skew-adjoint operators in signature $(2,n-2)$. Derived geometries ... More
A Theory of Complexity, Condition and RoundoffMar 25 2014Jun 06 2014We develop a theory of complexity for numerical computations that takes into account the condition of the input data and allows for roundoff in the computations. We follow the lines of the theory developed by Blum, Shub, and Smale for computations over ... More
The Large-Scale 3-point correlation function of SDSS Luminous Red GalaxiesNov 19 2010We present new measurements of the redshift-space three-point correlation function (3PCF) of Luminous Red Galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS). Using the largest dataset to date, the Data Release 7 (DR7) LRGs, and an improved binning ... More
On the constancy regions for mixed test idealsAug 25 2012Dec 04 2012In this note we study the partition of $\mathbb{R}_{\geq0}^{n}$ given by the regions where the mixed test ideals $\tau(\mathfrak{a}_{1}^{t_{1}}... \mathfrak{a}_{n}^{t_{n}})$ are constant. We show that each region can be described as the preimage of a ... More
Integrable Abelian Vortex-like solitonsDec 06 2016We propose a modified version of the Ginzburg-Landau energy functional admitting static solitons and determine all the Painlev\'e-integrable cases of its Bogomolny equations of a given class of models. Explicit solutions are determined in terms of the ... More
A remark on conformal $\SU(p,q)$-holonomyApr 18 2006If the conformal holonomy group $Hol(\mathcal{T})$ of a simply connected space with conformal structure of signature $(2p-1,2q-1)$ is reduced to $\U(p,q)$ then the conformal holonomy is already contained in the special unitary group $\SU(p,q)$. We present ... More
Counterexamples to Ruelle's inequality in the noncompact caseOct 16 2015In this paper we show that there exists a large family of smooth dynamical systems defined over noncompact spaces that does not satisfy Ruelle's inequality between entropy and Lyapunov exponents.
Ruelle's inequality and Pesin's entropy formula for the geodesic flow on negatively curved noncompact manifoldsJan 12 2016Jun 15 2016In this paper we study different notions of entropy of measure-preserving dynamical systems defined on noncompact spaces. We see that some classical results for compact spaces remain partially valid in this setting. We define a new kind of entropy for ... More
The Standard Candle Method for Type II-Plateau SupernovaeOct 30 2008In this thesis we study the "standardized candle method" using a sample of 37 nearby (redshift < 0.06) Type II-plateau supernovae with BVRI photometry and optical spectroscopy. An analytic procedure is implemented to fit light, color, and velocity curves. ... More
Normal Conformal Killing FormsJun 16 2004We introduce in this paper normal twistor equations for differential forms and study their solutions, the so-called normal conformal Killing forms. The twistor equations arise naturally from the canonical normal Cartan connection of conformal geometry. ... More
About Twistor Spinors with Zero in Lorentzian GeometryJun 15 2004Jul 28 2009We describe the local conformal geometry of a Lorentzian spin manifold $(M,g)$ admitting a twistor spinor $\phi$ with zero. Moreover, we describe the shape of the zero set of $\phi$. If $\phi$ has isolated zeros then the metric $g$ is locally conformally ... More
String Dual of N=1 Super Yang-Mills on the CylinderApr 30 2008We study the stringy description of N=1 supersymmetric SU(N) gauge theory on R^{1,2}xS^1. Our description is based on the known Maldacena-Nunez solution, properly modified to account for the compact dimension. The most interesting of its properties is ... More
A decomposition for the Schrodinger equation with applications to bilinear and multilinear estimatesJul 27 2015A new decomposition for frequency-localized solutions to the Schrodinger equation is given which describes the evolution of the wavefunction using a weighted sum of Lipschitz tubes. As an application of this decomposition, we provide a new proof of the ... More
About complex structures in conformal tractor calculusOct 28 2005Oct 31 2005The aim of this paper is to describe the geometry of conformal structures in Lorentzian signature, which admit a lightlike conformal Killing vector field whose corresponding adjoint tractor acts as complex structure on the standard tractor bundle of conformal ... More
C*-algebras associated with endomorphisms of groupsAug 06 2013Aug 07 2013In this work we construct a C*-algebra from an injective endomorphisms of some group G, allowing the endomorphism to have infinite cokernel. We generalize results obtained by I. Hirshberg and also by J. Cuntz and A. Vershik. In good cases we show that ... More
Conformal holonomy of bi-invariant metricsJun 15 2004We discuss in this paper the conformal geometry of bi-invariant metrics on compact semisimple Lie groups. For this purpose we develop a conformal Cartan calculus adapted to this problem. In particular, we derive an explicit formula for the holonomy algebra ... More
Twistor spinors with zero on Lorentzian 5-spaceFeb 27 2006We present in this paper a $C^1$-metric on an open neighbourhood of the origin in $\RR^{5}$. The metric is of Lorentzian signature $(1,4)$ and admits a solution to the twistor equation for spinors with a unique isolated zero at the origin. The metric ... More
H - T phase diagram of YbCo2Si2 with H // [100]Oct 30 2009May 23 2011We report on the first high-resolution dc-magnetisation ($M$) measurements on a single crystal of \ycs. $M$ was measured down to 0.05 K and in fields up to 12 T, with the magnetic field $H$ parallel to the crystallographic direction [100]. Two antiferromagnetic ... More
Proper motions of Local Group dwarf spheroidal galaxies I: First ground-based results for FornaxMay 26 2010In this paper we present in detail the methodology and the first results of a ground-based program to determine the absolute proper motion of the Fornax dwarf spheroidal galaxy. The proper motion was determined using bona-fide Fornax star members measured ... More
Large gaps imputation in remote sensed imagery of the environmentJun 22 2010Imputation of missing data in large regions of satellite imagery is necessary when the acquired image has been damaged by shadows due to clouds, or information gaps produced by sensor failure. The general approach for imputation of missing data, that ... More
Transient Anomaly Imaging in Visco-Elastic Media Obeying a Frequency Power-LawMay 31 2010In this work, we consider the problem of reconstructing a small anomaly in a viscoelastic medium from wave-field measurements. We choose Szabo's model to describe the viscoelastic properties of the medium. Expressing the ideal elastic field without any ... More
Strong pinning of vortices by antiferromagnetic domain boundaries in CeCo(In$_{1-x}$Cd$_x$)$_5$Sep 05 2016We have studied the isothermal magnetization $M(H)$ of CeCo(In$_{1-x}$Cd$_x$)$_5$ with $x$ = 0.0075 and 0.01 down to 50 mK. Pronounced field-history dependent phenomena occur in the coexistence regime of the superconducting and antiferromagnetic phases. ... More
Magnetic phase diagram of YbCo2Si2 derived from magnetization measurementsNov 12 2011Dec 20 2011We report on high-resolution dc-magnetization (M) measurements on a high-quality single crystal of YbCo2Si2. M was measured down to 0.05K and in fields up to 4T, with the magnetic field oriented along the crystallographic directions [100], [110] and [001] ... More
Basic parameters of three star clusters in the Small Magellanic Cloud: Kron 11, Kron 63 and NGC 121Aug 26 2008We present observations for three star clusters, Kron 11, Kron 63 and NGC 121, in the Small Magellanic Cloud. We have studied their structure and derived their fundamental parameters by means of their luminosity functions, their color magnitude diagrams ... More
Smoothed Analysis of Moore-Penrose InversionFeb 25 2010Apr 30 2010We perform a smoothed analysis of the condition number of rectangular matrices. We prove that, asymptotically, the expected value of this condition number depends only of the elongation of the matrix, and not on the center and variance of the underlying ... More
Constructive proof of extended Kapranov theoremOct 27 2008Kapranov Theorem is a well known generalization of Newton-Puiseux theorem for the case of several variables. This theorem is stated mainly in the context of tropical geometry. We present a new, constructive proof, that also characterizes the possible ... More
Tropical Plane Geometric Constructions: a Transfer Technique in Tropical GeometryNov 29 2005Oct 10 2007The notion of geometric construction is introduced. This notion allows to compare incidence configurations in the algebraic and tropical plane. We provide an algorithm such that, given a tropical instance of a geometric construction, it computes sufficient ... More
On the Chern-Simons topological term at finite temperatureSep 10 1997Sep 11 1997The parity-violating topological term in the effective action for 2+1 massive fermions is computed at finite temperature in the presence of a constant background field strength tensor. Gauge invariance of the finite-temperature effective action is also ... More
Transport and dynamics on open quantum graphsJul 13 2001We study the classical limit of quantum mechanics on graphs by introducing a Wigner function for graphs. The classical dynamics is compared to the quantum dynamics obtained from the propagator. In particular we consider extended open graphs whose classical ... More
Torsion points on y^2=x^6+1Oct 20 1997Let C be the curve y^2=x^6+1 of genus 2 over a field of characteristic zero. Consider C embedded in its Jacobian J by sending one of the points at infinity on C to the origin of J. In this brief note we show that the points of C whose image on J are torsion ... More
On graded polynomial identities of $sl_{2}(F)$ over a finite fieldNov 15 2013Apr 14 2015Let $F$ be a finite field of $char F > 3$ and $sl_{2}(F)$ be the Lie algebra of traceless $2\times 2$ matrices over $F$. This paper aims for the following goals: Find a basis for the $\mathbb{Z}_{2}$-graded identities of $sl_{2}(F)$; Find a basis for ... More
Smoothed analysis of componentwise condition numbers for sparse matricesFeb 25 2013We perform a smoothed analysis of the componentwise condition numbers for determinant computation, matrix inversion, and linear equations solving for sparse n times n matrices. The bounds we obtain for the ex- pectations of the logarithm of these condition ... More
Graded polynomial identities and central polynomials of matrices over an infinite integral domainMar 17 2014Aug 06 2014Let $K$ be an infinite integral domain and $M_{n}(K)$ be the algebra of all $n\times n$ matrices over $K$. This paper aims for the following goals: Find a basis for the graded identities for elementary grading in $M_{n}(K)$ when the neutral component ... More
Computing Hypercircles by Moving HyperplanesJun 07 2011Let K be a field of characteristic zero, alpha algebraic of degree n over K. Given a proper parametrization psi of a rational curve C, we present a new algorithm to compute the hypercircle associated to the parametrization psi. As a consequence, we can ... More
Control and Stabilization of the Benjamin-Ono Equation on a Periodic DomainSep 22 2012It was proved by Linares and Ortega that the linearized Benjamin-Ono equation posed on a periodic domain T with a distributed control supported on an arbitrary subdomain is exactly controllable and exponentially stabilizable. The aim of this paper is ... More
Fluctuations of the Longest Common Subsequence for Sequences of Independent BlocksJan 08 2010Nov 12 2010The problem of the fluctuation of the Longest Common Subsequence (LCS) of two i.i.d. sequences of length $n>0$ has been open for decades. There exist contradicting conjectures on the topic. Chvatal and Sankoff conjectured in 1975 that asymptotically the ... More
Componentwise condition numbers of random sparse matricesJul 07 2008Jul 08 2008We prove an O(log n) bound for the expected value of the logarithm of the componentwise (and, a fortiori, the mixed) condition number of a random sparse n x n matrix. As a consequence, small bounds on the average loss of accuracy for triangular linear ... More
Partial Crossed Product of a group G vs Crossed Product of S(G)May 23 2008In this work we present a new definition to the Partial Crossed Product by actions of inverse semigroups in a C^*-algebra, without using the covariant representations as Sieben did in [5]. Also we present an isomorphism between the partial crossed products ... More
A remark on the well-posedness of the degenerated Zakharov systemDec 07 2013We extend the local well-posedness theory for the Cauchy problem associated to a degenerated Zakharov system. The new main ingredients are the derivation of Strichartz and maximal function norm estimates for the linear solution of a Schrodinger type equation ... More
Tropical IdealsSep 13 2016We introduce and study a special class of ideals, called tropical ideals, in the semiring of tropical polynomials, with the goal of developing a useful and solid algebraic foundation for tropical geometry. The class of tropical ideals strictly includes ... More
Testing dynamic stabilisation in complex Langevin simulationsOct 28 2016Complex Langevin methods have been successfully applied in theories that suffer from a sign problem such as QCD with a chemical potential. We present and illustrate a novel method (dynamic stabilisation) that ensures that Complex Langevin simulations ... More
Nonequilibrium mesoscopic Fermi reservoirs distributions and particle current through a coherent quantum systemFeb 01 2013We study particle current and occupation distribution in a recently proposed model for coherent quantum transport. In this model a system connected to mesoscopic Fermi reservoirs (mesoreservoir) is driven out of equilibrium by the action of superreservoirs ... More
Higher cohomology for Anosov actions on certain homogeneous spacesJul 23 2011Aug 24 2012We study the smooth untwisted cohomology with real coefficients for the action on [SL(2, R) \times \cdot \cdot \cdot \times SL(2, R)]/{\Gamma} by the subgroup of diagonal matrices, where {\Gamma} is an irreducible lattice. In the top degree, we show that ... More
On real tropical bases and real tropical discriminantsNov 09 2013We explore the concept of real tropical basis of an ideal in the field of real Puiseux series. We show explicit tropical bases of zero-dimensional real radical ideals, linear ideals and hypersurfaces coming from combinatorial patchworking. But we also ... More
Stiefel tropical linear spacesMay 27 2013May 31 2015The tropical Stiefel map associates to a tropical matrix A its tropical Pluecker vector of maximal minors, and thus a tropical linear space L(A). We call the L(A)s obtained in this way Stiefel tropical linear spaces. We prove that they are dual to certain ... More
Counting the Number of Minimal Paths in Weighted Coloured-Edge GraphsDec 13 2011A weighted coloured-edge graph is a graph for which each edge is assigned both a positive weight and a discrete colour, and can be used to model transportation and computer networks in which there are multiple transportation modes. In such a graph paths ... More
Free Energy Evaluation in Polymer Translocation via Jarzynski EqualityJan 31 2014Apr 21 2014We perform, with the help of cloud computing resources, extensive Langevin simulations which provide free energy estimates for unbiased three dimensional polymer translocation. We employ the Jarzynski equality in its rigorous setting, to compute the variation ... More
Higher cohomology of parabolic actions on certain homogeneous spacesDec 14 2013We show that for a parabolic R^d-action on a compact quotient of PSL(2,R)^d, the cohomologies in degrees 1 through d-1 trivialize, and we give the obstructions to solving the degree-d coboundary equation, along with bounds on Sobolev norms of primitives. ... More
Bounded Model Checking of State-Space Digital Systems: The Impact of Finite Word-Length Effects on the Implementation of Fixed-Point Digital Controllers Based on State-Space ModelingOct 31 2016The extensive use of digital controllers demands a growing effort to prevent design errors that appear due to finite-word length (FWL) effects. However, there is still a gap, regarding verification tools and methodologies to check implementation aspects ... More
Weak forms of topological and measure theoretical equicontinuity: relationships with discrete spectrum and sequence entropyFeb 28 2014Sep 15 2015We define weaker forms of topological and measure theoretical equicontinuity for topological dynamical systems and we study their relationships with systems with discrete spectrum and zero sequence entropy. In the topological category we show systems ... More
The tropical discriminant in positive characteristicMar 05 2014We study singularities in tropical hypersurfaces defined by a valuation over a field of positive characteristic. We provide a method to compute the set of singular points of a tropical hypersurface in positive characteristic and the p-adic case. This ... More
Primal-Dual Algorithms for Non-negative Matrix Factorization with the Kullback-Leibler DivergenceDec 04 2014Non-negative matrix factorization (NMF) approximates a given matrix as a product of two non-negative matrices. Multiplicative algorithms deliver reliable results, but they show slow convergence for high-dimensional data and may be stuck away from local ... More
$\mathbb{Z}_{2}$-graded identities of the Grassmann algebra over a finite fieldMar 04 2014Dec 30 2014Let $F$ be a finite field with characteristic $p > 2$ and let $G$ be the unitary Grassmann algebra generated by an infinite dimensional vector space $V$ over $F$. In this paper, we determine a basis of the $\mathbb{Z}_{2}$-graded polynomial identities ... More
Neutrinos and the matter-antimatter asymmetry in the UniverseAug 12 2011The discovery of neutrino oscillations provides a solid evidence for nonzero neutrino masses and leptonic mixing. The fact that neutrino masses are so tiny constitutes a puzzling problem in particle physics. From the theoretical viewpoint, the smallness ... More
Solving Linear Problems with Finite Precision III: Sharp Expectation BoundsMay 11 2011We prove an O(log n) bound for the expectation of the logarithm of the condition number K for the computation of optimizers of linear programs.
Globalizations for partial (co)actions on coalgebrasOct 05 2015In this work, we introduce the notion of globalization for partial module coalgebra and for partial comodule coalgebra. We show that every partial module coalgebra is globalizable and we prove that the globalization for a partial comodule coalgebra there ... More
Well-posedness for the 1D Zakharov-Rubenchik systemSep 05 2008Sep 10 2008Local and global well-posedness results are established for the initial value problem associated to the 1D Zakharov-Rubenchik system. We show that our results are sharp in some situations by proving Ill-posedness results otherwise. The global results ... More
Tropical Resultants for Curves and Stable IntersectionMay 09 2008We introduce the notion of resultant of two planar curves in the tropical geometry framework. We prove that the tropicalization of the algebraic resultant can be used to compute the stable intersection of two tropical plane curves. It is shown that, for ... More
Non quark-antiquark light meson spectroscopyNov 19 2003Dec 04 2003In this talk I comment on some theoretical expectations for exotic light meson spectroscopy below 2 GeV and their potential interest for a future energy upgrade of DAFNE.
Random modification effect in the size of the fluctuation of the LCS of two sequences of i.i.d. blocksNov 11 2010Nov 12 2010The problem of the order of the fluctuation of the Longest Common Subsequence (LCS) of two independent sequences has been open for decades. There exist contradicting conjectures on the topic, due to Chvatal - Sankoff in 1975 and Waterman in 1994. In the ... More
Partial order approach to compute shortest paths in multimodal networksDec 14 2011Many networked systems involve multiple modes of transport. Such systems are called multimodal, and examples include logistic networks, biomedical phenomena, manufacturing process and telecommunication networks. Existing techniques for determining optimal ... More
On hitting times for simple random walk on dense Erdös-Rényi random graphsOct 07 2013Feb 27 2014Let $G(N,p)=(V,E)$ be an Erd\"os-R\'enyi random graph and $(X_n)_{n \in \mathbb{N}}$ be a simple random walk on it. We study the the order of magnitude of $\sum_{i \in V} \pi_ih_{ij} $ where $\pi_i=d_i / 2|E|$ for $d_i$ the number of neighbors of node ... More
Ultra-weak formulation of a hypersingular integral equation on polygons and DPG method with optimal test functionsSep 06 2013We present an ultra-weak formulation of a hypersingular integral equation on closed polygons and prove its well-posedness and equivalence with the standard variational formulation. Based on this ultra-weak formulation we present a discontinuous Petrov-Galerkin ... More
Master Equation approach to Reversible and Conservative Discrete SystemsAug 10 2016A master equation approach is applied to a reversible and conservative cellular automata model (Q2R). The Q2R model is a dynamical variation of the Ising model for ferromagnetism that possesses quite a rich and complex dynamics. The configurational space ... More
Markov Chain Modeling of Polymer Translocation Through PoresMay 31 2010Mar 20 2012We solve the Chapman-Kolmogorov equation and study the exact splitting probabilities of the general stochastic process which describes polymer translocation through membrane pores within the broad class of Markov chains. Transition probabilities which ... More
The Barycenter Method for Direct OptimizationJan 31 2018A randomized version of the recently developed barycenter method for derivative-free optimization has desirable properties of a gradient search. We develop a complex version to avoid evaluations at high-gradient points. The method, applicable to non-smooth ... More
Markovian Description of Unbiased Polymer TranslocationMar 20 2012We perform, with the help of cloud computing resources, extensive Langevin simulations which provide compelling evidence in favor of a general markovian framework for unbiased polymer translocation. Our statistical analysis consists of careful evaluations ... More
Invariant distributions and cohomology for geodesic flows and higher cohomology of higher-rank Anosov actionsOct 01 2012Jul 11 2013We are motivated by a conjecture of A. and S. Katok to study the smooth cohomologies of a family of Weyl chamber flows. The conjecture is a natural generalization of the Livshitz Theorem to Anosov actions by higher-rank abelian groups; it involves a description ... More
Constraining gravity with hadron physics: neutron stars, modified gravity and gravitational wavesNov 11 2016Nov 30 2016The finding of Gravitational Waves by the aLIGO scientific and VIRGO collaborations opens opportunities to better test and understand strong interactions, both nuclear-hadronic and gravitational. Assuming General Relativity holds, one can constrain hadron ... More
Curves that change genus can have arbitrarily many rational pointsJun 06 1995A singular curve over a non-perfect field K may not have a smooth model over K. Those are said to "change genus". If K is a global field of positive characteristic and C/K a curve that change genus, then C(K) is known to be finite. The purpose of this ... More
Dissipation in small systems: A Landau-Zener approachFeb 05 2016We establish a stochastic thermodynamics for a Fermionic level driven by a time-dependent force and interacting with initially thermalized levels playing the role of a reservoir. The driving induces consecutive avoided crossings between system and reservoir ... More
Evaluating arbitration and conflict resolution mechanisms in the Spanish WikipediaDec 10 2014In open collaborative projects like Wikipedia, interactions among users can produce tension and misunderstandings. Complex disputes require more sophisticated mechanisms of conflict resolution. In this paper, we examine the case of the Spanish Wikipedia ... More
Non-equilibrium Lorentz gas on a curved spaceJan 12 2007The periodic Lorentz gas with external field and iso-kinetic thermostat is equivalent, by conformal transformation, to a billiard with expanding phase-space and slightly distorted scatterers, for which the trajectories are straight lines. A further time ... More
Natural braneworld inflation and baryogenesisNov 26 2004May 29 2005In natural inflation models, the inflaton is a pseudo Nambu-Goldstone boson and the flatness of the potential is protected by shift symmetries. In this framework, a successful inflation requires the global symmetry to be spontaneously broken at a scale ... More
Asymptotic almost-equivalence of abstract evolution systemsApr 14 2009We study the asymptotic behavior of almost-orbits of abstract evolution systems in Banach spaces with or without a Lipschitz assumption. In particular, we establish convergence, convergence in average and almost-convergence of almost-orbits both for the ... More
Fields of Parametrization and Optimal Affine Reparametrization of Rational CurvesOct 30 2008In this paper we present three related results on the subject of fields of parametrization. Let C be a rational curve over a field of characteristic zero. Let K be a field finitely generated over Q, such that it is a field of definition of C but not a ... More
An Inverse Problem Approach for Content Popularity EstimationOct 26 2015The Internet increasingly focuses on content, as exemplified by the now popular Information Centric Networking paradigm. This means, in particular, that estimating content popularities becomes essential to manage and distribute content pieces efficiently. ... More
Extremal problems in de Branges spaces: the case of truncated and odd functionsDec 02 2014In this paper we find extremal one-sided approximations of exponential type for a class of truncated and odd functions with a certain exponential subordination. These approximations optimize the $L^1(\mathbb{R}, |E(x)|^{-2}dx)$-error, where $E$ is an ... More
Rescaling, thinning or complementing? On goodness-of-fit procedures for point process models and Generalized Linear ModelsNov 18 2010Generalized Linear Models (GLMs) are an increasingly popular framework for modeling neural spike trains. They have been linked to the theory of stochastic point processes and researchers have used this relation to assess goodness-of-fit using methods ... More
Metrisability of Painlevé equationsApr 12 2016We solve the metrisability problem for the six Painlev\'e equations, and more generally for all 2nd order ODEs with Painlev\'e property, and determine for which of these equations their integral curves are geodesics of a (pseudo) Riemannian metric on ... More
Khintchine types of translated coordinate hyperplanesMay 28 2014Jan 14 2015There has been great interest in developing a theory of "Khintchine types" for manifolds embedded in Euclidean space, and considerable progress has been made for curved manifolds. We treat the case of translates of coordinate hyperplanes, decidedly flat ... More
On the M-theory description of supersymmetric gluodynamicsMar 08 2007Jul 13 2007We study the stringy description of N=1 supersymmetric SU(N) gauge theory on R^{1,2} X S^1. Our description is based on the known Klebanov-Strassler and Maldacena-Nunez solutions, properly modified to account for the compact dimension. The presence of ... More
The twistor equation in Lorentzian spin geometryMay 04 2003In this paper we discuss the twistor equation in Lorentzian spin geometry. In particular, we explain the local conformal structure of Lorentzian manifolds, which admit twistor spinors inducing lightlike Dirac currents. Furthermore, we derive all local ... More
Crucial role of decoherence for electronic transport in molecular wires: Polyaniline as a case studyApr 30 2010Sep 02 2010In this work we attempt to elucidate the nature of conductivity in polymers by taking the acid-base doped polyaniline (PAni) polymer. We evaluate the PAni conductance by using realistic ab initio parameters and including decoherent processes within the ... More
Excitation-Transfer Plasmonic Nanosensors based on Dynamical Phase TransitionsOct 02 2012Dynamical Phase transitions (DPTs) describe the abrupt change in the dynamical properties of open systems when a single control parameter is slightly modified. Recently we found that this phenomenon is also present in a simple model of a linear array ... More
Adiabatic quantum motorsApr 17 2013When parameters are varied periodically, charge can be pumped through a mesoscopic conductor without applied bias. Here, we consider the inverse effect in which a transport current drives a periodic variation of an adiabatic degree of freedom. This provides ... More
Dynamical regimes of a quantum swap gate beyond the Fermi Golden RuleOct 06 2008Jan 26 2009We discuss how the bath's memory affects the dynamics of a swap gate. We present an exactly solvable model that shows various dynamical transitions when treated beyond the Fermi Golden Rule. By moving continuously a single parameter, the unperturbed Rabi ... More
Ferromagnetic Quantum Criticality in the Quasi-One-Dimensional Heavy Fermion Metal YbNi4P2Aug 22 2011We present a new Kondo-lattice system, YbNi4P2, which is a clean heavy-fermion metal with a severely reduced ferromagnetic ordering temperature at T_C=0.17K, evidenced by distinct anomalies in susceptibility, specific-heat, and resistivity measurements. ... More
Buffering plasmons in nanoparticle waveguides at the virtual-localized transitionDec 03 2009Jul 02 2010We study the plasmonic energy transfer from a locally excited nanoparticle (LE-NP) to a linear array of small NPs and we obtain the parametric dependence of the response function. An analytical expression allows us to distinguish the extended resonant ... More
Spaser and optical amplification conditions in gold-coated active nanoparticlesNov 08 2016Due to their many potential applications, there is an increasing interest in studying hybrid systems composed of optically active media and plasmonic metamaterials. In this work we focus on a particular system which consists of an optically active silica ... More
Plasmonic Graded-Chains as Deep-Subwavelength Light ConcentratorsFeb 04 2015We have studied the plasmonic properties of aperiodic arrays of identical nanoparticles (NPs) formed by two opposite and equal graded-chains (a chain where interactions change gradually). We found that these arrays concentrate the external electromagnetic ... More
The Brauer-Manin obstruction for subvarieties of abelian varieties over function fieldsDec 10 2006We prove that for a large class of subvarieties of abelian varieties over global function fields, the Brauer-Manin condition on adelic points cuts out exactly the rational points. This result is obtained from more general results concerning the intersection ... More
Brane world in Non-Riemannian GeometryDec 12 2012We carefully investigate the modified Einstein's field equation in a four dimensional (3-brane) arbitrary manifold embedded in a five dimensional Non-Riemannian bulk spacetime with a noncompact extra dimension. In this context the Israel-Darmois matching ... More