Results for "Julio-Omar Palacio-Niño"

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Evaluation Metrics for Unsupervised Learning AlgorithmsMay 14 2019Determining the quality of the results obtained by clustering techniques is a key issue in unsupervised machine learning. Many authors have discussed the desirable features of good clustering algorithms. However, Jon Kleinberg established an impossibility ... More
Evaluation Metrics for Unsupervised Learning AlgorithmsMay 14 2019May 23 2019Determining the quality of the results obtained by clustering techniques is a key issue in unsupervised machine learning. Many authors have discussed the desirable features of good clustering algorithms. However, Jon Kleinberg established an impossibility ... More
Unravelling Dzyaloshinskii-Moriya interaction and chiral nature of Graphene/Cobalt interfaceMar 20 2018Apr 02 2018A major challenge for future spintronics is to develop suitable spin transport channels with long spin lifetime and propagation length. Graphene can meet these requirements, even at room temperature. On the other side, taking advantage of the fast motion ... More
Franckeite: a naturally occurring van der Waals heterostructureJun 21 2016The fabrication of van der Waals heterostructures, artificial materials assembled by individually stacking atomically thin (2D) materials, is one of the most promising directions in 2D materials research. Until now, the most widespread approach to stack ... More
Neutrino masses in the $SU(4)_L \otimes U(1)_X$ electroweak extension of the standard modelAug 30 2016We study the neutrino mass generation in the $SU(4)_L \otimes U(1)_X$ electroweak extension of the standard model by considering non-renormalizable dimension five effective operators. It is shown that there exist two topologies for the realizations of ... More
Influence of Rotation on Stellar EvolutionJul 04 2013Jul 05 2013The Sun has been known to rotate for more than 4 centuries, and evidence is also available through direct measurements, that almost all stars rotate. In this lecture, I will propose a review of the different physical processes associated to rotation that ... More
A BRST charge for non-critical $\W_{2,s}$ stringsOct 28 1994We present a general argument for the construction of BRST charges of the `non-critical' $\W_{2,4}$, $\W_{2,5}$, $\W_{2,6}$, and $\W_{2,8}$ strings. This evidences the existence of BRST charges for a kind of soft-type algebras which can be constructed ... More
Reconstruction for multiwave imaging in attenuating media with large damping coefficientApr 20 2016Oct 16 2016In this article we study the reconstruction problem in TAT/PAT on an attenuating media. Namely, we prove a reconstruction procedure of the initial condition for the damped wave equation via Neumann series that works for arbitrary large smooth attenuation ... More
Boosting some type--D metricsMay 16 1996We are presenting a general solution to the classical Einstein--Maxwell--dilaton--axion equations starting from a metric of type--D. Namely, this stringy solution is the result of a transformation on a general vacuum type--D solution to the Einstein's ... More
A bibliometric approach to Systematic Mapping Studies: The case of the evolution and perspectives of community detection in complex networksFeb 08 2017Critical analysis of the state of the art is a necessary task when identifying new research lines worthwhile to pursue. To such an end, all the available work related to the field of interest must be taken into account. The key point is how to organize, ... More
I am 4 vho: new approach to improve seamless vertical hanover in heterogeneous wireless networksJun 06 2013Two mechanisms have been proposed independently by IEEE and 3GPP; namely, Media Independent Handover (MIH) and Access Network Discovery and Selection Function (ANDSF), respectively. These mechanisms enable a seamless Vertical Handover (VHO) between the ... More
Vortex matter in mesoscopic superconductorsSep 03 1998Superconducting mesoscopic devices in magnetic fields present novel properties which can only be accounted for by both the quantum confinement of the Cooper pairs and by the interaction between the magnetic-field-induced vortices. Sub-micrometer disks, ... More
Rotating models for evolved low-mass starsApr 29 2003Low mass stars (< 2-2.5 M_sun) exhibit, at all the stages of their evolution, signatures of processes that require challenging modeling beyond the standard stellar theory. In this paper we focus on their peculiarities while they climb the red giant branch ... More
Weak Bruhat order on the set of faces of the permutahedraApr 20 2004We extend the weak Bruhat order of a finite Coxeter group to the set of its coclasses, modulo parabolic standard subgroups. We use this order to describe associative algebra structures on the vector spaces spanned by the faces of permutahedra on one side, ... More
A comparison of evolutionary tracks for single Galactic massive starsOct 27 2013In this paper, we compare the currently available evolutionary tracks for Galactic massive stars. Our main goal is to highlight the uncertainties on the predicted evolutionary paths. We compute stellar evolution models with the codes MESA and STAREVOL. ... More
Anderson-like impurity in the one-dimensional t-J model: formation of local states and magnetic behaviourMar 08 2006We consider an integrable model describing an Anderson-like impurity coupled to an open $t$--$J$ chain. Both the hybridization (i.e. its coupling to bulk chain) and the local spectrum can be controlled without breaking the integrability of the model. ... More
Interplay between a quantum impurity and a boundary field in the SUSY t-J modelMar 13 2007Apr 13 2007We study the role of bound states appearing in different formulations of the Bethe ansatz for the supersymmetric t-J model with a boundary potential and an integrable impurity. For special values of the parameters describing the boundary and the impurity ... More
Complex geometric optics for symmetric hyperbolic systems II: nonlinear theory in one space dimensionFeb 12 2008This is the second part of a work aimed to study complex-phase oscillatory solutions of nonlinear symmetric hyperbolic systems. We consider, in particular, the case of one space dimension. That is a remarkable case, since one can always satisfy the \emph{naive} ... More
String model of the Hydrogen AtomJan 31 2007A non-moving electron hydrogen model is proposed, resolving a long standing contradiction (94 years) in the hydrogen atom. This, however, forces to not use the "in an orbit point particle kinetic energy" as the phenomenon responsible for the atom stability. ... More
Asymptotic solutions of pseudodifferential wave equationsNov 10 2004The aim of this paper is to give an account of some applications of pseudodifferential calculus for solving linear wave equations in the limit of high frequency/short wavelength waves. More specifically, on using as a benchmark the case of electromagnetic ... More
The relationship between the Wigner-Weyl kinetic formalism and the complex geometrical optics methodApr 26 2004Nov 04 2005The relationship between two different asymptotic techniques developed in order to describe the propagation of waves beyond the standard geometrical optics approximation, namely, the Wigner-Weyl kinetic formalism and the complex geometrical optics method, ... More
Is the Equation of State of strongly interacting matter observable ?Jun 06 2002I review the available empirical information on the equation of state of cold strongly interacting matter, as well as the prospects for obtaining new insights from the experimental study of gravitational waves emitted by neutron stars.
Reply to the Comment 'On large-N expansion'Dec 13 2002Fernandez Comment [1] on our pseudo-perturbative shifted-l expansion technique [2,3] is either unfounded or ambiguous.
Witten deformation using Lie groupoidsMar 27 2019We express Witten's deformation of Morse functions using deformation to the normal cone and $C^*$-modules. This allows us to obtain asympotitcs of the `large eigenvalues'. Our methods extend to Morse functions along a foliation. We construct the Witten ... More
Position-dependent mass harmonic oscillator: classical-quantum mechanical correspondence and ordering-ambiguityAug 10 2012Feb 22 2013We recycle Cruz et al.'s (Phys. Lett. A 369 (2007) 400) work on the classical and quantum position-dependent mass (PDM) oscillators. To elaborate on the ordering ambiguity, we properly amend some of the results reported in their work and discuss the classical ... More
Radial power-law position-dependent mass; Cylindrical coordinates, separability, and spectral signaturesApr 07 2011We discuss the separability of the position-dependent mass Hamiltonian in cylindrical coordinates in the framework of a radial power-law position-dependent mass. We consider two particular radial mass settings; a harmonic oscillator type, and a Coulombic ... More
On heat kernel decay for the random conductance modelSep 30 2017Mar 21 2018We study discrete time random walks in an environment of i.i.d. non-negative bounded conductances in $\mathbb{Z}^d$. We are interested in the anomaly of the heat-kernel decay. We improve recent results and techniques.
Interpretation of the Neutrino-Nucleus Cross SectionDec 05 2016I discuss the near-degeneracy between models of neutrino-nucleus interactions based on diverse assumptions, and analyze a specific example illustrating how the different reaction mechanisms taken into account, as well as the approximations associated ... More
On the ro-vibrational energies for the lithium dimer; maximum-possible rotational levelsJul 04 2014Mar 02 2015The Deng-Fan potential is used to discuss the reliability of the improved Greene-Aldrich approximation and the factorization recipe of Badawi et al.'s [17] for the central attractive/repulsive core. The factorization recipe is shown to be a more reliable ... More
Algorithm for factoring some RSA and Rabin moduliMar 21 2013In this paper we present a new efficient algorithm for factoring the RSA and the Rabin moduli in the particular case when the difference between their two prime factors is bounded. As an extension, we also give some theoretical results on factoring integers. ... More
Correlation functions of one-dimensional Bose-Fermi mixturesJul 15 2005We calculate the asymptotic behaviour of correlation functions as a function of the microscopic parameters for a Bose-Fermi mixture with repulsive interaction in one dimension. For two cases, namely polarized and unpolarized fermions the singularities ... More
Two remarks about multicurve graphs on infinite-type surfacesMar 14 2018After Fossas-Parlier, we consider two graphs $\mathcal{G}_{0}(S)$ and $\mathcal{G}_{\infty}(S)$, constructed from multicurves on connected, orientable surfaces of infinite-type. Our first result asserts that $\mathcal{G}_{\infty}(S)$ has finite diameter, ... More
On spectroscopic structure of two interacting electrons in a quantum dotFeb 07 2001Mar 12 2003The shifted 1/N expansion technique, used by El-Said (Phys. Rev. B 61, 13026 (2000)), to study the relative Hamiltonian of two interacting electrons confined in a quantum dot, is investigated. El-Said's results from SLNT are revised and results from an ... More
Spherical-separablility of non-Hermitian Dirac Hamiltonians and pseudo-PT-symmetryNov 25 2007Jan 24 2008A non-Hermitian P$_{\phi}$T$_{\phi}$-symmetrized spherically-separable Dirac Hamiltonian is considered. It is observed that the descendant Hamiltonians H$_{r}$, H$_{\theta}$, and H$_{\phi}$ play essential roles and offer some user-feriendly options as ... More
On the quasi - exact solvability of a singular potential in D - dimensions; confined and unconfinedJan 27 2001Oct 10 2001The D -dimensional quasi - exact solutions for the singular even - power anharmonic potential $V(q)=aq^2+bq^{-4}+cq^{-6}$ are reported. We show that whilst Dong and Ma's [5] quasi - exact ground - state solution (in D=2) is beyond doubt, their solution ... More
Complex geometric optics for symmetric hyperbolic systems I: linear theoryFeb 12 2008We obtain an asymptotic solution for $\ep \to 0$ of the Cauchy problem for linear first-order symmetric hyperbolic systems with oscillatory initial values written in the eikonal form of geometric optics with frequency $1/\ep$, but with complex phases. ... More
Le probleme de l'isomorphisme de graphes est dans PJan 15 2008Jan 19 2008This paper has been withdrawn by the author, due to possible counter-examples.
Nuclear response beyond the Fermi gas modelJul 14 2003The Fermi gas model, while providing a reasonable qualitative description of the continuum nuclear response, does not include the effects of dynamical nucleon-nucleon correlations in the initial and final states, that have long been recognized to play ... More
Interpretation of y-scaling of the nuclear responseAug 31 1999The behavior of the nuclear matter response in the region of large momentum transfer, in which plane wave impulse approximation predicts the onset of y-scaling, is discussed. The theoretical analysis shows that scaling violations produced by final state ... More
How much nuclear physics do we need, to understand the neutrino nucleus cross section ?Jun 17 2009Over the past two decades, electron scattering experiments have clearly exposed the limits of the independent particle model description of atomic nuclei. I will briefly outline the dynamics leading to the appearance of strong correlation effects, and ... More
New variant of ElGamal signature schemeJan 15 2013In this paper, a new variant of ElGamal signature scheme is presented and its security analyzed. We also give, for its theoretical interest, a general form of the signature equation.
Label Visualization and Exploration in IRDec 10 2016There is a renaissance in visual analytics systems for data analysis and sharing, in particular, in the current wave of big data applications. We introduce RAVE, a prototype that automates the generation of an interface that uses facets and visualization ... More
The Perron-Frobenius Theorem for Markov SemigroupsJan 23 2014Let $P^V_t$, $t\ge0$, be the Schrodinger semigroup associated to a potential $V$ and Markov semigroup $P_t$, $t\ge0$, on $C(X)$. Existence is established of a left eigenvector and right eigenvector corresponding to the spectral radius $e^{\lambda_0t}$ ... More
Spectral Functions and Nuclear ResponseSep 17 2007I discuss the relation between the nuclear response and the Green function describing the propagation of a nucleon in the nuclear medium. Within this formalism, the widely used expressions in terms of spectral functions can be derived in a consistent ... More
Final state interactions in the electroweak nuclear responseFeb 13 2006I review the description of the electroweak nuclear response at large momentum transfer within nonrelativistic many-body theory. Special consideration is given to the effects of final state interactions, which are known to be large in both inclusive and ... More
Neutron star matter equation of state and gravitational wave emissionJul 21 2005The EOS of strongly interacting matter at densities ten to fifteen orders of magnitude larger than the typical density of terrestrial macroscopic objects determines a number of neutron star properties, including the pattern of gravitational waves emitted ... More
Electron- and neutrino-nucleus scatteringAug 19 2004I review the main features of the nuclear response extracted from electron scattering data. The emerging picture clearly shows that the shell model does not provide a fully quantitative description of nuclear dynamics. On the other hand, many body approaches ... More
HI deficiency in groups : what can we learn from EridanusSep 14 2004The HI content of the Eridanus group of galaxies is studied using the GMRT observations and the HIPASS data. A significant HI deficiency up to a factor of 2-3 is observed in galaxies in the Eridanus group. The deficiency is found to be directly correlated ... More
Scaling in many-body systems and proton responseApr 15 2002The observation of scaling in processes in which a weakly interacting probe delivers large momentum ${\bf q}$ to a many-body system reflects the dominance of incoherent scattering off target constituents. While a suitably defined scaling function can ... More
Particle Statistics in Quantum Information ProcessingDec 29 2004Particle statistics is a fundamental part of quantum physics, and yet its role and use in the context of quantum information have been poorly explored so far. After briefly introducing particle statistics and the Symmetrization Postulate, I will argue ... More
Indistinguishable Particles in Quantum Mechanics: An IntroductionNov 01 2005In this article, we discuss the identity and indistinguishability of quantum systems and the consequent need to introduce an extra postulate in Quantum Mechanics to correctly describe situations involving indistinguishable particles. This is, for electrons, ... More
Fusion algebras, symmetric polynomials, orbits of N-groups, and rank-level dualityJun 15 2004A method of computing fusion coefficients for Lie algebras of type $A_{n-1}$ on level $k$ was recently developed by A. Feingold and M. Weiner \cite{FW} using orbits of $\mathbb{Z}_n^k$ under the permutation action of $S_k$ on $k$-tuples. They got the ... More
Many-Body Theory of the Electroweak Nuclear ResponseJul 08 2008After a brief review of the theoretical description of nuclei based on nonrelativistic many-body theory and realistic hamiltonians, these lectures focus on its application to the analysis of the electroweak response. Special emphasis is given to electron-nucleus ... More
An algorithm for finding the Independence Number of a graphJan 03 2008Jan 09 2008In this paper, we prove that for every connected graph G, there exists a split graph H with the same independence number and the same order. Then we propose a first algorithm for finding this graph, given the degree sequence of the input graph G. Further, ... More
An algorithm for solving the Independent Set problemSep 17 2007Sep 21 2007This paper has been withdrawn by the author, due an error in claim 1.
The Flat DeuteronOct 18 2005The new model was applied to the femtometer toroidal structures found for the deuteron. It was possible to relate the magnetic moment and the energy of the particle to the torus geometric parameters. Excellent agreement between the magnetic moment of ... More
A different view of deep inelastic electron-proton scatteringDec 11 2000Deep inelastic electron-proton scattering is analyzed in the target rest frame using a theoretical approach suitable to describe many-body systems of {\em bound} constituents subject to {\em interactions}. At large three-momentum transfer $\magq$, this ... More
Perturbed Coulombic potentials in Dirac and Klein-Gordon equationsJul 10 2003Feb 17 2004A relativistic extension of our pseudo-shifted $\ell$-expansion technique is presented to solve for the eigenvalues of Dirac and Klein-Gordon equations. Once more we show the numerical usefulness of its results via comparison with available numerical ... More
Insecure primitive elements in an ElGamal signature protocolSep 04 2015Consider the classical ElGamal digital signature scheme based on the modular relation $\alpha^m\equiv y^r\, r^s\ [p]$. In this work, we prove that if we can compute a natural integer $i$ such that $\alpha^i\ mod\ p$ is smooth and divides $p-1$, then it ... More
Transgression forms as source for topological gravity and Chern-Simons-Higgs theoriesNov 06 2014Two main gauge invariant off-shell models are studied in this Thesis. I) Poincare-invariant topological gravity in even dimensions is formulated as a transgression field theory whose gauge connections are associated to linear and nonlinear realizations ... More
Area Versus Speed Trade-off Analysis of a WiMAX Deinterleaver Circuit DesignOct 10 2014Trade-off is one of the main design parameters in the field of electronic circuit design. Whereas smaller electronics devices which use less hardware due to techniques like hardware multiplexing or due to smaller devices created due to techniques developed ... More
On the nonlinear dynamics of a position-dependent mass-driven Duffing-type oscillator: Lagrange and Newton equations' equivalenceApr 19 2013Using a generalized coordinate along with a proper invertible coordinate transformation, we show that the Euler-Lagrange equation used by Bagchi et al. 16 is in clear violation of the Hamilton's principle. We also show that Newton's equation of motion ... More
Final state interactions in the nuclear response at large momentum transferJan 15 2013The convolution approach, widely employed to describe final state interactions in the response of many-body systems, is derived from the expression of the nuclear response in the zeroth-order ladder approximation. Within this framework, the folding function, ... More
On Dirac equation for a Coulomb scalar, vector, and tensor interactionAug 30 2011In their recent paper (Inter. J. Mod. Phys. A 26 (2011) 1011), Zarrinkamar and coauthors have considered the radial Dirac equation for a Coulomb scalar, vector and tensor interaction. The exact solutions for the energy eigenvalues they have reported for ... More
A particular case of the Level increasing Conjecture for Type A fusion algebrasApr 27 2011A particular case of the level increasing conjecture for type A fusion coefficientes is proved for when one the weights is a multiple of the first fundamental weight.
Auxiliary quantization constraints on the von Roos ordering-ambiguity at zero binding energies; azimuthally symmetrized cylindrical coordinatesAug 29 2011Aug 01 2012Using azimuthally symmetrized cylindrical coordinates, we report the consequences of zero-energy quantal states on the von Roos Hamiltonian. A position-dependent mass M({\rho},\phi,z)=bz^{j}{\rho}^{2\u{psion}+1}/2 is used. We show that the zero-energy ... More
Off-critical local height probabilities on a plane and critical partition functions on a cylinderNov 09 2017We compute off-critical local height probabilities in regime-III restricted solid-on-solid models in a $4 N$-quadrant spiral geometry, with periodic boundary conditions in the angular direction, and fixed boundary conditions in the radial direction, as ... More
CMB in the river frame and gauge invariance at second orderAug 01 2017Apr 22 2018GAUGE INVARIANCE: The Sachs-Wolfe formula describing the Cosmic Microwave Background (CMB) temperature anisotropies is one of the most important relations in cosmology. Despite its importance, the gauge invariance of this formula has only been discussed ... More
A Framework for Moment InvariantsJul 17 2018For more than half a century, moments have attracted lot ot interest in the pattern recognition community.The moments of a distribution (an object) provide several of its characteristics as center of gravity, orientation, disparity, volume. Moments can ... More
The center of the wreath product of symmetric groups algebraNov 28 2018We consider the wreath product of two symmetric groups as a group of blocks permutations and we study its conjugacy classes. We give a polynomiality property for the structure coefficients of the center of the wreath product of symmetric groups algebra. ... More
Conditions on the generator for forging ElGamal signatureJan 14 2013This paper describes new conditions on parameters selection that lead to an efficient algorithm for forging ElGamal digital signature. Our work is inspired by Bleichenbacher's ideas.
Matter and Light in FlatlandJan 28 2004Using a non-material current through three new dimensions. It was possible to build a particle-space model (a higher dimensional object intersecting a lower dimensional world). The new dimensions solve the old problem of equal sign walls huge electric ... More
Scaling in many-body systems and proton structure functionOct 17 2001The observation of scaling in processes in which a weakly interacting probe delivers large momentum ${\bf q}$ to a many-body system simply reflects the dominance of incoherent scattering off target constituents. While a suitably defined scaling function ... More
On a 1D nonlocal transport equation with nonlocal velocity and subcritical or supercritical diffusionMar 16 2016Apr 11 2016We study a 1D transport equation with nonlocal velocity with subcritical or supercritical dissipation. For all data in the weighted Sobolev space $H^{k}(w_{\lambda,\kappa}) \cap L^{\infty},$ with $k=\max(0,3/2-\alpha)$ and $w_{\lambda, \kappa}$ is a given ... More
On the correlation energies for two interacting electrons in a parabolic quantum dotJul 09 2001Jul 10 2001The correlation energies for two interacting electrons in a parabolic quantum dot are studied via a pseudo-perturbation recipe. It is shown that the central spike term, ($m^2-1/4)/r^2$, plays a distinctive role in determining the spectral properties of ... More
Nuclear Physics with Electroweak ProbesFeb 26 2009In recent years, the italian theoretical Nuclear Physics community has played a leading role in the development of a unified approach, allowing for a consistent and fully quantitative description of the nuclear response to electromagnetic and weak probes. ... More
New results on collectivity with ALICEOct 12 2017An overview of recent ALICE results aimed to understand collective phenomena in Pb-Pb collisions at the LHC is presented. These include the centrality dependence of the transverse momentum ($p_{\rm T}$) distributions of charged pions, kaons, and protons ... More
CMB anisotropies at all orders: the non-linear Sachs-Wolfe formulaJun 26 2017Aug 14 2017We obtain the non-linear generalization of the Sachs-Wolfe + integrated Sachs-Wolfe (ISW) formula describing the CMB temperature anisotropies. Our formula is valid at all orders in perturbation theory, is also valid in all gauges and includes scalar, ... More
Large-scale multiscale particle models in inhomogeneous domains: modelling and implementationSep 13 2016In this thesis, we develop multiscale models for particle simulations in population dynamics. These models are characterised by prescribing particle motion on two spatial scales: microscopic and macroscopic. At the microscopic level, each particle has ... More
Weak error expansion of the implicit Euler schemeApr 25 2013In this paper, we extend the Talay Tubaro theorem to the implicit Euler scheme.
Global and local existence for the dissipative critical SQG equation with small oscillationsAug 04 2013Jun 03 2015This article is devoted to the study of the critical dissipative surface quasi-geostrophic $(SQG)$ equation in $\mathbb{R}^2$. For any initial data $\theta_{0}$ belonging to the space $\Lambda^{s} ( H^{s}_{uloc}(\mathbb{R}^2)) \cap L^\infty(\mathbb{R}^2)$, ... More
Schedulability Analysis of Distributed Real-Time Applications under Dependence and Several Latency ConstraintsJan 21 2013This paper focuses on the analysis of real-time non preemptive multiprocessor scheduling with precedence and several latency constraints. It aims to specify a schedulability condition which enables a designer to check a priori -without executing or simulating- ... More
(1+1)-Dirac bound states in one-dimension; position-dependent Fermi velocity and massSep 29 2012Jan 28 2013We extend Panella and Roy's [13] work on one-dimensional heterostructure for massless Dirac particles with position-dependent (PD) velocity. We consider Dirac particles where both the mass and velocity are position-dependent. Bound states in the continuum ... More
On submeasures on Boolean algebrasDec 31 2012Mar 04 2013We present a collection of observations and results concerning submeasures on Boolean algebras. They are all motivated by Maharam's problem and Talagrand's construction that solved it.
Entangled Bloch Spheres: Bloch Matrix and Two Qubit State SpaceFeb 04 2016Jun 20 2016We represent a two-qubit density matrix in the basis of Pauli matrix tensor products, with the coefficients constituting a Bloch matrix, analogous to the single qubit Bloch vector. We find the quantum state positivity requirements on the Bloch matrix ... More
A Frobenius formula for the structure coefficients of double-class algebras of Gelfand pairsFeb 06 2015We generalise some well known properties of irreducible characters of finite groups to zonal spherical functions of Gelfand pairs. This leads to a Frobenius formula for Gelfand pairs. For a given Gelfand pair, the structure coefficients of its associated ... More
The Adaptive LQ RegulatorJan 14 2019Mar 14 2019The optimal adaptive control of a linear system in a signal-plus-noise setting with infinite horizon LQ regulator cost is studied. The class of partially observed linear systems for which the certainty equivalence property holds is identified. It is also ... More
A Note on the Mean Value of $L$--functions in Function FieldsAug 13 2012An asymptotic formula for the sum $\sum L(1,\chi)$ is established for a family of hyperelliptic curves of genus $g$ over a fixed finite field $\mathbb{F}_q$ as $g\rightarrow\infty$ making use of the analogue of the approximate functional equation for ... More
Aspects of fermion dynamics from Lorentz symmetry violationDec 26 2016In this thesis we are interested in understanding how Lorentz symmetry violation can affect some features of fermion dynamics and, perhaps, help to solve some well-known problems in particle physics, such as the origin of neutrino masses and oscillations. ... More
The conjugacy problem for Thompson-like groupsJul 25 2018Aug 04 2018In this paper we generalize techniques of Belk-Matucci to solve the conjugacy problem for every Thompson-like group $V_n(H)$, where $n \geq 2$ and $H$ is a subgroup of the symmetric group on $n$ elements. We use this to prove that, if $n \neq m$, $V_n(H)$ ... More
Rudnick and Soundararajan's Theorem for Function FieldsNov 03 2015In this paper we prove a function field version of a theorem by Rudnick and Soundararajan about lower bounds for moments of quadratic Dirichlet $L$-functions. We establish lower bounds for the moments of quadratic Dirichlet $L$--functions associated to ... More
Singular Contractions of W-algebrasJun 08 1992Many $W$-algebras (e.g. the $W_N$ algebras) are consistent for all values of the central charge except for a discrete set of exceptional values. We show that such algebras can be contracted to new consistent degenerate algebras at these exceptional values ... More
A critical analysis of vacancy-induced magnetism in mono and bilayer grapheneMar 29 2012The observation of intrinsic magnetic order in graphene and graphene-based materials relies on the formation of magnetic moments and a sufficiently strong mutual interaction. Vacancies are arguably considered the primary source of magnetic moments. Here ... More
Orbital eigenchannel analysis for ab-initio quantum transport calculationsOct 26 2005Feb 17 2006We show how to extract the orbital contribution to the transport eigenchannels from a first-principles quantum transport calculation in a nanoscopic conductor. This is achieved by calculating and diagonalizing the first-principles transmission matrix ... More
Spin effects in a confined 2DEG: Enhancement of the g-factor, spin-inversion states and their far-infrared absorptionAug 15 1995We investigate several spin-related phenomena in a confined two-dimensional electron gas (2DEG) using the Hartree-Fock approximation for the mutual Coulomb interaction of the electrons. The exchange term of the interaction causes a large splitting of ... More
Integrability conditions for Compound Random MeasuresJul 21 2017Nov 12 2017Compound random measures (CoRM's) are a flexible and tractable framework for vectors of completely random measure. In this paper, we provide conditions to guarantee the existence of a CoRM. Furthermore, we prove some interesting properties of CoRM's when ... More
Discrimination and analysis of interactions in non-contact Scanning Force MicroscopyFeb 13 2006Mar 01 2006A method for the separation and quantitative characterization of the electrostatic and Van der Waals contribution to tip-sample interaction in non-contact Scanning Force Microscopy is presented. It is based on the simultaneous measurement of cantilever ... More
Non-equilibrium Transport in the Anderson model of a biased Quantum Dot: Scattering Bethe Ansatz PhenomenologyMar 28 2010May 18 2011We derive the transport properties of a quantum dot subject to a source-drain bias voltage at zero temperature and magnetic field. Using the Scattering Bethe Anstaz, a generalization of the traditional Thermodynamic Bethe Ansatz to open systems out of ... More
Nonlinear stability of 2-solitons of the Sine-Gordon equation in the energy spaceJan 30 2018In this article we prove that 2-soliton solutions of the sine-Gordon equation (SG) are orbitally stable in the natural energy space of the problem. The solutions that we study are the {\it 2-kink, kink-antikink and breather} of SG. In order to prove this ... More
Character sums for elliptic curve densitiesMar 12 2017If $E$ is an elliptic curve over $\mathbb{Q}$, then it follows from work of Serre and Hooley that, under the assumption of the Generalized Riemann Hypothesis, the density of primes $p$ such that the group of $\mathbb{F}_p$-rational points of the reduced ... More