Results for "Jordi Marzo"

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Discrepancy of minimal Riesz energy pointsJul 10 2019We find upper bounds for the spherical cap discrepancy of the set of minimizers of the Riesz $s$-energy on the sphere $\mathbb S^d.$ Our results are based in bounds for a Sobolev discrepancy introduced by Thomas Wolff in an unpublished manuscript where ... More
Riesz basis of exponentials for a union of cubes in R^{d}Jan 12 2006We extend to several dimensions the result of K. Seip and Y.I. Lyubarskii that proves the existence of Riesz basis of exponentials for a finite union of intervals with equals lengths.
Marcinkiewicz-Zygmund inequalities and interpolation by spherical harmonicsNov 16 2006We find necessary density conditions for Marcinkiewicz-Zygmund inequalities and interpolation for spaces of spherical harmonics with respect to the L^p norm. Moreover, we prove that there are no complete interpolation families for p\neq 2.
$L^\infty$ to $L^p$ constants for Riesz projectionsMay 11 2010The norm of the Riesz projection from $L^\infty(\T^n)$ to $L^p(\T^n)$ is considered. It is shown that for $n=1$, the norm equals $1$ if and only if $p\le 4$ and that the norm behaves asymptotically as $p/(\pi e)$ when $p\to \infty$. The critical exponent ... More
Pointwise estimates for the Bergman kernel of the weighted Fock spaceOct 02 2008We prove upper pointwise estimates for the Bergman kernel of the weighted Fock space of entire functions in $L^2(e^{-2\phi})$ where $\phi$ is a subharmonic function with $\Delta \phi$ a doubling measure. We derive estimates for the canonical solution ... More
Equidistribution of the Fekete points on the sphereAug 08 2008The Fekete points are the points that maximize a Vandermonde-type determinant that appears in the polynomial Lagrange interpolation formula. They are well suited points for interpolation formulas and numerical integration. We prove the asymptotic equidistribution ... More
Expected Riesz energy of some determinantal processes on flat toriNov 23 2016We compute the expected Riesz energy of random points on flat tori drawn from certain translation invariant determinantal processes and determine the process in the family providing the optimal asymptotic expected Riesz energy.
Equivalent norms for polynomials on the sphereMar 20 2007We study comparison of Lp norms of polynomials on the sphere with respect to doubling measures. From our description it follows an uncertainty principle for square integrable functions on the sphere. We consider also weighted uniform versions of this ... More
Uniformly bounded orthonormal polynomials on the sphereMay 21 2014Nov 06 2014Given any $\varepsilon>0$, we construct an orthonormal system of $n_k$ uniformly bounded polynomials of degree at most $k$ on the unit sphere in $\mathbb R^{m+1}$ where $n_k$ is bigger than $1-\varepsilon$ times the dimension of the space of polynomials ... More
Energy and discrepancy of rotationally invariant determinantal point processes in high dimensional spheresNov 08 2015Jul 19 2016We study expected Riesz s-energies and linear statistics of some determinantal processes on the sphere. In particular, we compute the expected Riesz and logarithmic energies of the determinantal processes given by the reproducing kernel of the space of ... More
Asymptotically optimal designs on compact algebraic manifoldsDec 20 2016We find t-designs on compact algebraic manifolds with a number of points comparable to the dimension of the space of polynomials of degree t on the manifold. This generalizes results on the sphere by Bondarenko, Radchenko and Viazovska. Of special interest ... More
Sampling and interpolation in de Branges spaces with doubling phaseMar 02 2011The de Branges spaces of entire functions generalise the classical Paley-Wiener space of square summable bandlimited functions. Specifically, the square norm is computed on the real line with respect to weights given by the values of certain entire functions. ... More
Zeros of random functions generated with de Branges kernelsApr 07 2015We study the point process given by the set of real zeros of random sums of orthonormal bases of reproducing kernels of de Branges spaces. Examples of these kernels are the cardinal sine, Airy and Bessel kernels. We find an explicit formula for the first ... More
A sequence of polynomials with optimal condition numberMar 04 2019We find an explicit sequence of univariate polynomials of arbitrary degree with optimal condition number. This solves a problem posed by Michael Shub and Stephen Smale in 1993.
Gap probabilities for the cardinal sineAug 15 2011We study the zero set of random analytic functions generated by a sum of the cardinal sine functions that form an orthogonal basis for the Paley-Wiener space. As a model case, we consider real-valued Gaussian coefficients. It is shown that the asymptotic ... More
The Kadets 1/4 theorem for polynomialsDec 20 2007We determine the maximal angular perturbation of the (n+1)th roots of unity permissible in the Marcinkiewicz-Zygmund theorem on L^p means of polynomials of degree at most n. For p=2, the result is an analogue of the Kadets 1/4 theorem on perturbation ... More
Optimal Trading Execution with Nonlinear Market Impact: An Alternative Solution MethodNov 29 2011We consider the optimal trade execution strategies for a large portfolio of single stocks proposed by Almgren (2003). This framework accounts for a nonlinear impact of trades on average market prices. The results of Almgren (2003) are based on the assumption ... More
On the Torelli problem and Jacobian Nullwerte in genus threeJan 28 2009We give a closed formula for recovering a non-hyperelliptic genus three curve from its period matrix, and derive some identities between Jacobian Nullwerte in dimension three.
The European Space Agency {\Gaia} mission: exploring the GalaxyMay 31 2011The {\Gaia} astrometric mission was approved by the European Space Agency in 2000 and the construction of the spacecraft and payload is on-going for a launch in late 2012. {\Gaia} will continuously scan the entire sky for 5 years, yielding positional ... More
Prospects in Classical Nova Modeling and NucleosynthesisJul 27 2004Classical novae are fascinating stellar events, at the crossroads of astrophysics, nuclear physics and cosmochemistry. In this review, we outline the history of nova modeling with special emphasis on recent advances and perspectives in multidimensional ... More
Singular perturbations of Blaschke Products and connectivity of Fatou componentsFeb 03 2017The goal of this paper is to study the family of singular perturbations of Blaschke products given by $B_{a,\lambda}(z)=z^3\frac{z-a}{1-\overline{a}z}+\frac{\lambda}{z^2}$. We focus on the study of these rational maps for parameters $a$ in the punctured ... More
Measuring market liquidity: An introductory surveyDec 28 2011Asset liquidity in modern financial markets is a key but elusive concept. A market is often said to be liquid when the prevailing structure of transactions provides a prompt and secure link between the demand and supply of assets, thus delivering low ... More
Some characterizations of Howson PC-groupsSep 23 2014We show that in the class of partially commutative groups, the conditions of being Howson, being fully residually free, and being free product of free-abelian groups, are equivalent.
Nuclear Ashes: Reviewing Thirty Years of Nucleosynthesis in Classical NovaeSep 10 2002One of the observational evidences in support of the "thermonuclear runaway model" for the classical nova outburst relies on the accompanying nucleosynthesis. In this paper, we stress the relevant role played by nucleosynthesis in our understanding of ... More
Rational maps with Fatou components of arbitrarily large connectivityApr 03 2017We study the family of singular perturbations of Blaschke products $B_{a,\lambda}(z)=z^3\frac{z-a}{1-\overline{a}z}+\frac{\lambda}{z^2}$. We analyse how the connectivity of the Fatou components varies as we move continuously the parameter $\lambda$. We ... More
Effective Trade ExecutionJun 22 2012This paper examines the role of algorithmic trading in modern financial markets. Additionally, order types, characteristics, and special features of algorithmic trading are described under the lens provided by the large development of high frequency trading ... More
Phase transition and vacuum stability in the classically conformal B-L modelNov 27 2018Within classically conformal models, the spontaneous breaking of scale invariance is usually associated to a strong first order phase transition that results in a gravitational wave background within the reach of future space-based interferometers. In ... More
Equidistribution and $β$ ensemblesSep 22 2015We find the precise rate at which the empirical measure associated to a $\beta$-ensemble converges to its limiting measure. In our setting the $\beta$-ensemble is a random point process on a compact complex manifolds distributed according to the $\beta$ ... More
Towards a viable scalar interpretation of $R_{D^{(*)}}$May 21 2018Aug 27 2018Recent measurements of semileptonic B-meson decays seemingly imply violations of lepton flavor universality beyond the Standard Model predictions. With three-level explanations based on extended Higgs sectors being strongly challenged by the measurements ... More
Experiments of Interfacial Roughening in Hele-Shaw Flows with Weak Quenched DisorderJul 25 2002We have studied the kinetic roughening of an oil--air interface in a forced imbibition experiment in a horizontal Hele--Shaw cell with quenched disorder. Different disorder configurations, characterized by their persistence length in the direction of ... More
Two-dimensional simulations of mixing in classical novae: the effect of the white dwarf composition and massJul 27 2018Context. Classical novae are explosive phenomena that take place in stellar binary systems. They are powered by mass transfer from a low-mass main sequence star onto a white dwarf (either CO or ONe). The material accumulates for 10+4 - 10+5 yr until ignition ... More
The LHC di-photon excess and Gauge Coupling Unification in Extra $Z^\prime$ Heterotic-String Derived ModelsJun 03 2016Oct 19 2016The di-photon excess observed at the LHC can be explained as a Standard Model singlet that is produced and decays by heavy vector-like colour triplets and electroweak doublets in one-loop diagrams. The characteristics of the required spectrum are well ... More
Overview of Bohmian MechanicsJun 05 2012Jan 09 2013This chapter provides a comprehensive overview of the Bohmian formulation of quantum mechanics. It starts with a historical review of the difficulties found by Louis de Broglie, David Bohm, and John S. Bell to convince the scientific community about the ... More
Boundary multipliers of a family of Möbius invariant function spacesApr 16 2015For $1<p<\infty$ and $0<s<1$, let $\mathcal{Q}^p_ s (\mathbb{T})$ be the space of those functions $f$ which belong to $ L^p(\mathbb{T})$ and satisfy \[ \sup_{I\subset \mathbb{T}}\frac{1}{|I|^s}\int_I\int_I\frac{|f(\zeta)-f(\eta)|^p}{|\zeta-\eta|^{2-s}}|d\zeta||d\eta|<\infty, ... More
Cosmology and CPT violating neutrinosJul 25 2017The combination Charge Conjugation-Parity-Time Reversal(CPT) is a fundamental symmetry in our current understanding of nature. As such, testing CPT violation is a strongly motivated path to explore new physics. In this paper we study CPT violation in ... More
On the wave length of smooth periodic traveling waves of the Camassa-Holm equationMar 09 2015This paper is concerned with the wave length $\lambda$ of smooth periodic traveling wave solutions of the Camassa-Holm equation. The set of these solutions can be parametrized using the wave height $a$ (or "peak-to-peak amplitude"). Our main result establishes ... More
Genus two curves with quaternionic multiplication and modular jacobianMay 09 2008We describe a method to determine all the isomorphism classes of principal polarizations of the modular abelian surfaces $A_f$ with quaternionic multiplication attached to a normalized newform $f$ without complex multiplication. We include an example ... More
Simulation and understanding of quantum crystalsMay 19 2016Quantum crystals abound in the whole range of solid-state species. Below a certain threshold temperature the physical behavior of rare gases (4He and Ne), molecular solids (H2 and CH4), and some ionic (LiH), covalent (graphite), and metallic (Li) crystals ... More
Universal avalanche statistics and triggering close to failure in a mean field model of rheological fractureJan 05 2018The hypothesis of critical failure relates the presence of an ultimate stability point in the structural constitutive equation of materials to a divergence of characteristic scales in the microscopic dynamics responsible for deformation. Avalanche models ... More
Simulation and understanding of quantum crystalsMay 19 2016Dec 13 2016Quantum crystals abound in the whole range of solid-state species. Below a certain threshold temperature the physical behavior of rare gases (4He and Ne), molecular solids (H2 and CH4), and some ionic (LiH), covalent (graphite), and metallic (Li) crystals ... More
The Limit of Mechanical Stability in Quantum Crystals: A Diffusion Monte Carlo Study of Solid 4HeAug 11 2014We present a first-principles study of the energy and elastic properties of solid helium at pressures below the range in which is energetically stable. We find that the limit of mechanical stability in hcp 4He is $P_{s}$ = -33.82 bar, which lies significantly ... More
On the determination of anomalies in supersymmetric theoriesMay 30 1996Dec 03 1996We develop an efficient technique to compute anomalies in supersymmetric theories by combining the so-called nonlocal regularization method and superspace techniques. To illustrate the method we apply it to a four dimensional toy model with potentially ... More
Irreversible Adsorption of particles after diffusing in a gravitational fieldSep 05 1996In this paper we analyze the influence of transport mechanisms (diffusion and sedimentation) on the structure of monolayers of particles irreversibly adsorbed on a line. We focus our attention on the dependence of the radial distribution function $g(r)$ ... More
Higher Loop Anomalies and their Consistency Conditions in Nonlocal RegularizationJul 29 1996An algebraic program of computation and characterization of higher loop BRST anomalies is presented. We propose a procedure for disentangling a genuine{\it local} higher loop anomaly from the quantum dressings of lower loop anomalies. For such higher ... More
Genetics of polynomials over local fieldsSep 17 2013Jun 10 2014Let $(K,v)$ be a discrete valued field with valuation ring $\oo$, and let $\oo_v$ be the completion of $\oo$ with respect to the $v$-adic topology. In this paper we discuss the advantages of manipulating polynomials in $\oo_v[x]$ in a computer by means ... More
A star disrupted by a stellar black hole as the origin of the cloud falling toward the Galactic centerFeb 24 2012Jul 11 2012We propose that the cloud moving on a highly eccentric orbit near the central black hole in our Galaxy, reported by Gillessen et al., is formed by a photoevaporation wind originating in a disk around a star that is tidally perturbed and shocked at every ... More
Atomic decomposition for Bergman spaces with exponential type weightsMay 03 2014Aug 31 2015We show that any function in a Bergman space with exponential type weights admits a representation in terms of an infinite series of kernel functions.
Microscopic approach to the bcc phase of solid 4HeSep 06 2011Oct 19 2011The coexistence between the hcp and bcc phases of solid 4He at fixed pressure, and at three different temperatures, is studied by means of the path integral Monte Carlo method. Microscopic results for the main energetic and structure properties of the ... More
Towards the use of asteroseismology to investigate the nature of dark matterAug 03 2010Oct 19 2010The annihilation of huge quantities of captured dark matter (DM) particles inside low-mass stars has been shown to change some of the stellar properties, such as the star's effective temperature or the way the energy is transported throughout the star. ... More
A Test of the Collisional Dark Matter Hypothesis from Cluster LensingFeb 02 2000Nov 02 2001Spergel & Steinhardt proposed the possibility that the dark matter particles are self-interacting, as a solution to two discrepancies between the predictions of cold dark matter models and the observations: first, the observed dark matter distribution ... More
A note on 'Exact and approximate methods for a one-dimensional minimax bin-packing problem' [Annals of Operations Research (2013) 206:611-626]Feb 07 2014In a recent paper, Brusco, K\"ohn and Steinley [Ann. Oper. Res. 206:611-626 (2013)] conjecture that the 2 bins special case of the one-dimensional minimax bin-packing problem with bin size constraints might be solvable in polynomial time. In this note, ... More
Nuclear astrophysics: the unfinished quest for the origin of the elementsJul 12 2011Half a century has passed since the foundation of nuclear astrophysics. Since then, this discipline has reached its maturity. Today, nuclear astrophysics constitutes a multidisciplinary crucible of knowledge that combines the achievements in theoretical ... More
Thermonuclear Runaways on Accreting White Dwarfs: Models of Classical Novae ExplosionsJan 11 2000The mechanism of classical novae explosions is explained, together with some of their observational properties. The scarce but not null impact of novae in the chemical evolution of the Milky Way is analyzed, as well as their relevance for the radioactivity ... More
Nucleosynthesis in Classical Novae: ONe vs. CO White DwarfsSep 16 1997Detailed nucleosynthesis in the ejecta of classical novae has been determined for a grid of hydrodynamic nova models. The reported 14 evolutionary sequences, followed from the onset of accretion up to the explosion and ejection stages, span a range of ... More
Astrometric Light-Travel Time signature of sources in nonlinear motionNov 09 2005Context:Very precise planned space astrometric missions and recent improvements on imaging capabilities require a detailed review of the assumptions of classical astrometric modeling. Aims:We show that Light-Travel Time must be taken into account to model ... More
Bifurcation of critical periods from Pleshkan's isochronesNov 14 2008Pleshkan proved in 1969 that, up to a linear transformation and a constant rescaling of time, there are four isochrones in the family of cubic centers with homogeneous nonlinearities $\mathscr C_3.$ In this paper we prove that if we perturb any of these ... More
Carleson Measures and Toeplitz operators for weighted Bergman spaces on the unit ballJan 11 2014Some new characterizations on Carleson measures for weighted Bergman spaces on the unit ball involving product of functions are obtained. For these we characterize bounded and compact Toeplitz operators between weighted Bergman spaces. The above results ... More
Long range Ising model for credit risk modeling in homogeneous portfoliosJan 21 2004Within the framework of maximum entropy principle we show that the finite-size long-range Ising model is the adequate model for the description of homogeneous credit portfolios and the computation of credit risk when default correlations between the borrowers ... More
Randomly weighted CNNs for (music) audio classificationMay 01 2018Feb 14 2019The computer vision literature shows that randomly weighted neural networks perform reasonably as feature extractors. Following this idea, we study how non-trained (randomly weighted) convolutional neural networks perform as feature extractors for (music) ... More
Curves of genus 2 with group of automorphisms isomorphic to D_8 or D_12Mar 17 2002In this paper we classify curves of genus 2 with group of automorphisms isomorphic to D_8 or D_12 over an arbitrary field k (of characteristic different from 2 in the D_8 case and from 2 and 3 in the D_{12} case) up to k-isomorphism. As an application ... More
A Toeplitz type operator on Hardy spaces in the unit ballMay 11 2018We study a Toeplitz type operator $Q_\mu$ between the holomorphic Hardy spaces $H^p$ and $H^q$ of the unit ball. Here the generating symbol $\mu$ is assumed to a positive Borel measure. This kind of operator is related to many classical mappings acting ... More
Weak factorization and Hankel forms for weighted Bergman spaces on the unit ballJul 17 2014Jan 08 2015We establish weak factorizations for a weighted Bergman space $A^p_{\a}$, with $1<p<\infty$, into two weighted Bergman spaces on the unit ball of $\C^n$. To obtain this result, we characterize bounded Hankel forms on weighted Bergman spaces on the unit ... More
Extreme Energy Cosmic Rays (EECR) Observation Capabilities of an ``Airwatch from Space'' MissionDec 18 1997The longitudinal development and other characteristics of the EECR induced atmospheric showers can be studied from space by detecting the fluorescence light induced in the atmospheric nitrogen. According to the Airwatch concept a single fast detector ... More
Bosonic dark matter halos: excited states and relaxation in the potential of the ground stateFeb 28 2018An ultra-light axion field with mass $\sim 10^{-22}\ {\rm eV}$, also known as wave or fuzzy dark matter, has been proposed as a component of the dark matter in the Universe. We study the evolution of the axion dark matter distribution in the central region ... More
Structural distortions in the Euro interbank market: The role of 'key players' during the recent market turmoilJul 23 2012We study the frictions in the patterns of trades in the Euro money market. We characterize the structure of lending relations during the period of recent financial turmoil. We use network-topology method on data from overnight transactions in the Electronic ... More
On the universality of the scaling of fluctuations in traffic on complex networksFeb 11 2006We study the scaling of fluctuations with the mean of traffic in complex networks using a model where the arrival and departure of "packets" follow exponential distributions, and the processing capability of nodes is either unlimited or finite. The model ... More
Bell correlations at finite temperatureMay 01 2018Nov 16 2018We show that spin systems with infinite-range interactions can violate at thermal equilibrium a multipartite Bell inequality, up to a finite critical temperature $T_c$. Our framework can be applied to a wide class of spin systems and Bell inequalities, ... More
Geometric and arithmetic relations concerning origamiSep 16 2014Sep 25 2014We present a formalization of geometric instruments that considers separately geometric and arithmetic aspects of them. We introduce the concept of tool, which formalizes a physical instrument as a set of axioms representing its geometric capabilities. ... More
White dwarf collisions and the meteoritic Ne-E annomalySep 24 2018The analysis of noble gases in primitive meteorites has shown the existence of anomalous isotopic abundances when compared with the average Solar System values. In particular it has been found that some graphite grains contain a unexpected high abundance ... More
Carleson measures, Riemann-Stieltjes and multiplication operators on a general family of function spacesJul 18 2013Let $\mu$ be a nonnegative Borel measure on the unit disk of the complex plane. We characterize those measures $\mu$ such that the general family of spaces of analytic functions, $F(p,q,s)$, which contain many classical function spaces, including the ... More
Anomalies and Wess-Zumino Terms in an Extended, Regularized Field-Antifield FormalismJan 31 1994Sep 15 1994Quantization of anomalous gauge theories with closed, irreducible gauge algebra within the extended Field-Antifield formalism is further pursued. Using a Pauli-Villars (PV) regularization of the generating functional at one loop level, an alternative ... More
First-principles modeling of three-body interactions in highly compressed solid heliumSep 15 2015We present a new set of three-body interaction models based on the Bruch-McGee (BM) potential that are suitable for the study of the energy, structural and elastic properties of solid 4He at high pressure. Our ab initio three-body potentials are obtained ... More
Modular abelian varieties over number fieldsMay 15 2009Aug 31 2012The main result of this paper is a characterization of the abelian varieties $B/K$ defined over Galois number fields with the property that the zeta function $L(B/K;s)$ is equivalent to the product of zeta functions of non-CM newforms for congruence subgroups ... More
Analysis of power-law exponents by maximum-likelihood mapsFeb 09 2012Feb 15 2012Maximum-likelihood exponent maps have been studied as a technique to increase the understanding and improve the fit of power-law exponents to experimental and numerical simulation data, especially when they exhibit both upper and lower cut-offs. The use ... More
Field of moduli and field of definition for curves of genus 2Jul 02 2002Let M_2 be the moduli space that classifies genus 2 curves. If a curve C is defined over a field k, the corresponding moduli point P=[C] is defined over k. Mestre solved the converse problem for curves with Aut(C) isomorphic to C_2. Given a moduli point ... More
Canonical equivalence relations on nets of $PS_{c_0}$Oct 31 2006Jun 09 2007We give a list of canonical equivalence relations on discrete nets of the positive unit sphere of $c_0$. This generalizes results of W. T. Gowers and A. D. Taylor.
Design of an achromatic, high numerical aperture optical assembly with a solid immersion lensMay 30 2019Efficiently collecting light emitted or scattered from nanoscale systems, which can be embedded in a high-index medium, is a challenge for fundamental spectroscopic studies and commercial applications of quantum dots, color centers, single molecules, ... More
Maximum likelihood approach for several stochastic volatility modelsApr 16 2012Jul 02 2012Volatility measures the amplitude of price fluctuations. Despite it is one of the most important quantities in finance, volatility is not directly observable. Here we apply a maximum likelihood method which assumes that price and volatility follow a two-dimensional ... More
Three-dimensional simulations of turbulent convective mixing in ONe and CO classical nova explosionsJun 28 2016Classical novae are thermonuclear explosions that take place in the envelopes of accreting white dwarfs in binary systems. The material piles up under degenerate conditions, driving a thermonuclear runaway. The energy released by the suite of nuclear ... More
The spatial distribution and luminosity function of the open cluster NGC 4815Dec 01 1997NGC 4815 is a distant and populous open cluster, which lies in the galactic plane in a region of strong absorption. As a consequence, its membership, spatial distribution and luminosity function are not well determined. In this paper, we present an algorithm ... More
Evolutionary Algorithm for Graph AnonymizationOct 01 2013Mar 26 2014In recent years there has been a significant increase in the use of graphs as a tool for representing information. It is very important to preserve the privacy of users when one wants to publish this information, especially in the case of social graphs. ... More
On unconditionally saturated Banach spacesMay 14 2008We prove a structural property of the class of unconditionally saturated separable Banach spaces. We show, in particular, that for every analytic set $\aaa$, in the Effros-Borel space of subspaces of $C[0,1]$, of unconditionally saturated separable Banach ... More
On the lattice of subgroups of a free group: complements and rankMay 29 2019A $\vee$-complement of a subgroup $H \leqslant \mathbb{F}_n$ is a subgroup $K \leqslant \mathbb{F}_n$ such that $H \vee K = \mathbb{F}_n$. If we also ask $K$ to have trivial intersection with $H$, then we say that $K$ is a $\oplus$-complement of $H$. ... More
Signatures of the Origin of High-Energy Cosmic Rays in Cosmological Gamma-Ray BurstsJan 04 1996We derive observational consequences of the hypothesis that cosmic rays (CR's) of energy $>10^{19}eV$ originate in the same cosmological objects producing gamma-ray bursts (GRB's). Inter-galactic magnetic fields $\gtrsim 10^{-12} G$ are required in this ... More
Formation of the Black Holes in the Highest Redshift QuasarsJun 09 2004Aug 30 2004The recent discovery of luminous quasars up to a redshift z=6.43 has renewed interest in the formation of black holes massive enough to power quasars. If black holes grow by Eddington-limited gas accretion with a radiative efficiency of at least 10%, ... More
Wilsonian vs. 1PI renormalization group flow irreversibilityFeb 22 1996Apr 11 1996We present a line of reasoning based on the analysis of scale variations of the Wilsonian partition function and the trace of the stress tensor in a curved manifold which results in a statement of irreversibility of Wilsonian renormalization group flow ... More
THE GUNN-PETERSON EFFECT FROM UNDERDENSE REGIONS IN A PHOTOIONIZED INTERGALACTIC MEDIUMFeb 13 1995We use the Zel'dovich approximation and another analytical approximation to calculate the evolution under gravitational instability of the underdense regions of a photoionized intergalactic medium (IGM). We find that over most of the spectrum of a quasar, ... More
Gravitational Lensing Effects on the Baryonic Acoustic Oscillation Signature in the Redshift-Space Correlation FunctionJan 07 2009Aug 07 2010Measurements of the baryonic acoustic oscillation (BAO) peak in the redshift-space correlation function yield the angular diameter distance D_A(z) and the Hubble parameter H(z) as a function of redshift, constraining the properties of dark energy and ... More
Search for Extratidal Features Around 17 Globular Clusters in the Sloan Digital Sky SurveyAug 17 2010The dynamical evolution of a single globular cluster and also of the entire Galactic globular cluster system has been studied theoretically in detail. In particular, simulations show how the 'lost' stars are distributed in tidal tails emerging from the ... More
Self-shielding Effects on the Column Density Distribution of Damped Lyman Alpha SystemsJan 17 2002Feb 26 2002We calculate the column density distribution of damped Lyman alpha systems, modeled as spherical isothermal gaseous halos ionized by the external cosmic background. The effects of self-shielding introduce a hump in this distribution, at a column density ... More
On the lattice of subgroups of a free group: complements and rankMay 29 2019Jun 12 2019A $\vee$-complement of a subgroup $H \leqslant \mathbb{F}_n$ is a subgroup $K \leqslant \mathbb{F}_n$ such that $H \vee K = \mathbb{F}_n$. If we also ask $K$ to have trivial intersection with $H$, then we say that $K$ is a $\oplus$-complement of $H$. ... More
Warnings and Caveats in Brain ControllabilityMay 17 2017In this work we challenge the main conclusions of Gu et al work (Controllability of structural brain networks. Nature communications 6, 8414, doi:10.1038/ncomms9414, 2015) on brain controllability. Using the same methods and analyses on four datasets ... More
Naturalness and Dark Matter Properties of the BLSSMJun 05 2017Jun 07 2017In this report, we compare the naturalness and Dark Matter (DM) properties of the Minimal Supersymmetric Standard Model (MSSM) and the $B-L$ Supersymmetric Standard Model (BLSSM), with universality in both cases. We do this by adopting standard measures ... More
Schatten classes of integration operators on Dirichlet spacesFeb 11 2013We address the question of describing the membership to Schatten-Von Neumann ideals $\mathcal{S}_ p$ of integration operators $(T_ g f)(z)=\int_{0}^{z}f(\zeta)\,g'(\zeta)\,d\zeta$ acting on Dirichlet type spaces. We also study this problem for multiplication, ... More
Microlensing in the Galactic Bulge: Effects of the Disk Behind the BulgeMay 20 1998Jun 05 2000A large number of microlensing events have been observed in the direction of the Galactic bulge, with a measured optical depth in the range 2 - 3 x 10^{-6}. It has been shown that most of these events are due to bulge stars being lensed by other bulge ... More
The Distribution of Mass and Gas in the Center of Clusters of Galaxies Implied by X-Ray and Lensing ObservationsApr 04 1995Observations of gravitational lensing indicate that the mass distribution in clusters of galaxies (where most of the mass is dark matter) is highly peaked towards the center, while X-ray observations imply that the gas is more extended. The additional ... More
Multisymplectic unified formalism for Einstein-Hilbert GravityMay 01 2017Mar 28 2018We present a covariant multisymplectic formulation for the Einstein-Hilbert model of General Relativity. As it is described by a second-order singular Lagrangian, this is a gauge field theory with constraints. The use of the unified Lagrangian-Hamiltonian ... More
$Z'$, Higgses and heavy neutrinos in $U(1)'$ models: from the LHC to the GUT scaleMay 10 2016We study a class of non-exotic minimal $U(1) '$ extensions of the Standard Model, which includes all scenarios that are anomaly-free with the ordinary fermion content augmented by one Right-Handed neutrino per generation, wherein the new Abelian gauge ... More
A simulation code to assist designing space missions of the Airwatch typeOct 06 1998The design of an Airwatch type space mission can greatly benefit from a flexible simulation code for establishing the values of the main parameters of the experiment. We present here a code written for this purpose. The cosmic ray primary spectrum at ... More
On-the-fly coarse-graining methodology for the simulation of chain formation of superparamagnetic colloids in strong magnetic fieldsNov 24 2011Feb 06 2012The aim of this work is the description of the chain formation phenomena observed in colloidal suspensions of superparamagnetic nanoparticles under high magnetic fields. We propose a new methodology based on an on-the-fly Coarse-Grain (CG) model. Within ... More