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Results for "Roberto J. López-Sastre"

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ISA$^2$: Intelligent Speed Adaptation from AppearanceOct 11 2018In this work we introduce a new problem named Intelligent Speed Adaptation from Appearance (ISA$^2$). Technically, the goal of an ISA$^2$ model is to predict for a given image of a driving scenario the proper speed of the vehicle. Note this problem is ... More
Unsupervised learning from videos using temporal coherency deep networksJan 24 2018Oct 11 2018In this work we address the challenging problem of unsupervised learning from videos. Existing methods utilize the spatio-temporal continuity in contiguous video frames as regularization for the learning process. Typically, this temporal coherence of ... More
Learning to Exploit the Prior Network Knowledge for Weakly-Supervised Semantic SegmentationApr 13 2018Feb 22 2019Training a Convolutional Neural Network (CNN) for semantic segmentation typically requires to collect a large amount of accurate pixel-level annotations, a hard and expensive task. In contrast, simple image tags are easier to gather. With this paper we ... More
In pixels we trust: From Pixel Labeling to Object Localization and Scene CategorizationJul 19 2018While there has been significant progress in solving the problems of image pixel labeling, object detection and scene classification, existing approaches normally address them separately. In this paper, we propose to tackle these problems from a bottom-up ... More
Learning Short-Cut Connections for Object CountingMay 08 2018Nov 15 2018Object counting is an important task in computer vision due to its growing demand in applications such as traffic monitoring or surveillance. In this paper, we consider object counting as a learning problem of a joint feature extraction and pixel-wise ... More
Representation Learning for Visual-Relational Knowledge GraphsSep 07 2017Mar 31 2018A visual-relational knowledge graph (KG) is a multi-relational graph whose entities are associated with images. We introduce ImageGraph, a KG with 1,330 relation types, 14,870 entities, and 829,931 images. Visual-relational KGs lead to novel probabilistic ... More
Embarrassingly Simple Model for Early Action ProposalOct 17 2018Oct 18 2018Early action proposal consists in generating high quality candidate temporal segments that are likely to contain an action in a video stream, as soon as they happen. Many sophisticated approaches have been proposed for the action proposal problem but ... More
Deep Anomaly Detection for Generalized Face Anti-SpoofingApr 17 2019Face recognition has achieved unprecedented results, surpassing human capabilities in certain scenarios. However, these automatic solutions are not ready for production because they can be easily fooled by simple identity impersonation attacks. And although ... More
The challenge of simultaneous object detection and pose estimation: a comparative studyJan 24 2018Detecting objects and estimating their pose remains as one of the major challenges of the computer vision research community. There exists a compromise between localizing the objects and estimating their viewpoints. The detector ideally needs to be view-invariant, ... More
Generalized Presentation Attack Detection: a face anti-spoofing evaluation proposalApr 12 2019Over the past few years, Presentation Attack Detection (PAD) has become a fundamental part of facial recognition systems. Although much effort has been devoted to anti-spoofing research, generalization in real scenarios remains a challenge. In this paper ... More
Critical phenomena in the majority voter model on two dimensional regular latticesJan 19 2014Apr 29 2014In this work we studied the critical behavior of the critical point as function of the number of nearest neighbors on two dimensional regular lattices. We performed numerical simulations on triangular, hexagonal and bilayer square lattices. Using standard ... More
Short-time dynamic in the Majority vote model: The ordered and disordered initial casesDec 31 2009This work presents short-time Monte Carlo simulations for the two dimensional Majority-vote model starting from ordered and disordered states. It has been found that there are two pseudo-critical points, each one within the error-bar range of previous ... More
Partial-Duplex Amplify-and-Forward Relaying: Spectral Efficiency Analysis under Self-InterferenceAug 21 2017We propose a novel mode of operation for Amplify-and-Forward relays in which the spectra of the relay input and output signals partially overlap. This partial-duplex relaying mode encompasses half-duplex and full-duplex as particular cases. By viewing ... More
Differential characters and cohomology of the moduli of flat ConnectionsNov 19 2017Let $\pi\colon P\to M$ be a principal bundle and $p$ an invariant polynomial of degree r on the Lie algebra of the structure group. The theory of Chern-Simons differential characters is exploited to define an homology map $\chi^{k} : H_{2r-k-1}(M)\times ... More
Analytic solutions to various dissipation models of the simple and driven quantum harmonic oscillatorJan 18 2018We obtain analytic solutions to various models of dissipation of the quantum harmonic oscillator, employing a simple method in the Wigner function Fourier transform description of the system; and study as an exemplification, the driven open quantum harmonic ... More
Molten salts database for energy applicationsJul 28 2013Sep 14 2013The growing interest in energy applications of molten salts is justified by several of their properties. Their possibilities of usage as a coolant, heat transfer fluid or heat storage substrate, require thermo-hydrodynamic refined calculations. Many researchers ... More
The energy gap of the compound FeSe0.5Te0.5 determined by specific heat and point contact spectroscopyJul 06 2015The superconductor $FeSe_{0.5}Te_{0.5}$ was studied with Point Contact spectroscopy and specific heat in polycrystalline samples. The transition temperature determined by magnetic measurement was $T_C =14.5$ K. The size of the energy gap measured by junctions ... More
Global diffeomorphism of the Lagrangian flow-map defining Equatorially trapped water wavesMay 07 2015The aim of this paper is to prove that a three dimensional Lagrangian flow which defines equatorially trapped water waves is dynamically possible. This is achieved by applying a mixture of analytical and topological methods to prove that the nonlinear ... More
An alternative order-parameter for non-equilibrium generalized spin models on honeycomb latticesDec 11 2015An alternative definition for the order-parameter is proposed, for a family of non-equilibrium spin models with up-down symmetry on honeycomb lattices, and which depends on two parameters. In contrast to the usual definition, our proposal takes into account ... More
Antiferromagnetic majority voter model on square and honeycomb latticesSep 15 2015An antiferromagnetic version of the well-known majority voter model on square and honeycomb lattices is proposed. Monte Carlo simulations give evidence for a continuous order-disorder phase transition in the stationary state in both cases. Precise estimates ... More
Bohr-Fourier series on solenoids via its transversal variationMar 01 2019The Bohr-Fourier series development on one dimensional solenoids is analyzed by using invariant functions and extending Bohr's theory through the study of transversal variation
A nonlocal two phase Stefan problemJul 04 2013We study a nonlocal version of the two-phase Stefan problem, which models a phase transition problem between two distinct phases evolving to distinct heat equations. Mathematically speaking, this consists in deriving a theory for sign-changing solutions ... More
Desorption of hydrocarbon chains by association with ionic and nonionic surfactants under flow as a mechanism for enhanced oil recoveryAug 31 2017The need to extract oil from wells where it is embedded on the surfaces of rocks has led to the development of new and improved enhanced oil recovery techniques. One of those is the injection of surfactants with water vapor, which promotes desorption ... More
ALIOLI: Adaptive and Lucky Imaging Optics Lightweight InstrumentJul 24 2018As a consequence of the evolution in the design and of the modularity of its components, AOLI for the William Herschel Telescope (WHT 4.2m) is much smaller and more efficient than its previous designs. This success has leaded us to plan to condense it ... More
The Geometry of Numbers in the Digital AgeOct 20 2018We present a transformation, based on the B\'ezout's identity, which maps the set of pairs of relatively prime numbers $(p,q)$ with fixed $p$ and $0<q<p$, to pairs of relatively prime numbers in the $p\times p$ square in $\mathbb R^2$, in such a way that ... More
Physics of non-steady state diffusion of lightweight atoms in a heavy atom matrix. Introducing an open-source tool for simulated-experiments in fluid mechanicsOct 23 2013The practice-based learning methodologies offer to undergraduate professors different ways to illustrate certain general physic principles. Traditional experimental workbenches have been extensively used during decades for academic lessons in order to ... More
A new attempt towards the unification of space-time and internal gauge symmetriesOct 03 2006The neat formulation that describes the gauge interactions associated with internal symmetries is extended to the case of a simple, yet non-trivial, symmetry group structure which mixes gravity and electromagnetism by associating a gauge symmetry with ... More
Lagrangian Formalism on Jet-Gauge and Jet-Diffeomorphism Groups: Towards a Unification of Gravity with Internal Gauge InteractionsJul 29 2005In this talk the description of gauge theories associated with internal symmetries is extended to the case in which the symmetry group is the space-time translation group (recovering Einstein's theory) using the standard jet-bundle formalism. We also ... More
Determination of the Higgs boson mass by the cancellation of ultraviolet divergencies in the $SU(2)_L\times U(1)_Y$ TheoryApr 20 1995We assume the vanishing of the quadratic divergences in the $SU(2)_L \otimes U(1)$ electroweak theory. Using $\,$ the $\,$ top $\,$ mass $\,$ value reported recently by the CDF Collaboration $m_t = 176 \pm 8 \pm 10 GeV$, we predict the mass of the Higgs ... More
Representations of hypergeometric functions for arbitrary parameter values and their useSep 08 2016Oct 05 2016Integral representations of hypergeometric functions proved to be a very useful tool for studying their properties. The purpose of this paper is twofold. First, we extend the known representations to arbitrary values of the parameters and show that the ... More
3-D modelling of the collimated bipolar outflows of compact planetary nebulae with WR-type central starsJun 22 2012We present high-resolution, long-slit spectroscopic observations of five compact ($\leq$ 10 arcsec) planetary nebulae located close to the galactic bulge region and for which no high spatial resolution images are available. The data have been drawn from ... More
A general procedure to find ground state solutions for finite $N$ M(atrix) theory. Reduced models and SUSY quantum cosmologyJan 07 2015Mar 05 2015We propose a general method to find exact ground state solutions to the SU($N$) invariant matrix model arising from the quantization of the 11-dimensional supermembrane action in the light-cone gauge. We illustrate the method by applying it to lower dimensional ... More
Revised Diagnostic Diagrams for Planetary NebulaeFeb 08 2006Diagnostic diagrams of electron density - excitation for a sample of 613 planetary nebulae are presented. The present extensive sample allows the definition of new statistical limits for the distribution of planetary nebulae in the log [Ha/[SII]] vs log ... More
Convergence of row sequences of simultaneous Fourier-Padé approximationMar 07 2012We consider row sequences of simultaneous rational approximations constructed in terms of Fourier expansions and prove a Montessus de Ballore type theorem.
The thermal instanton determinant in compact formJun 26 2014Nov 20 2014The thermal instanton determinant for the gauge group $SU(2)$ can be reduced to a form involving two simple functions. Various boundary conditions can easily incorporated. Only a two dimensional integral has to be done numerically. As an example we compute ... More
A HIC Primitive Spinodal Decomposition SignatureMar 29 2005Mar 29 2005Evidence of a primitive spinodal decomposition has been obtained for central Ni+Ni Heavy Ion Collision, since higher order charge correlations show a peak when four fragments of size equal to 6 are produced with an excitation of 4.75 MeV. This can be ... More
Caloron correction to the effective potential in thermal gluodynamicsJan 02 2015The effective potential in thermal gluodynamics has stable minima in perturbation theory. There the Wilson line is center group valued and eigenvalues of the Wilson line stay clustered. Calorons with non-trivial holonomy contribute to one loop order a ... More
Linear nonlocal diffusion problems in metric measure spacesDec 17 2014The aim of this paper is to provide a comprehensive study of some linear nonlocal diffusion problems in metric measure spaces. These include, for example, open subsets in $\mathbb{R}^N$, graphs, manifolds, multi-structures or some fractal sets. For this, ... More
An instrumental puzzle: the modular integration of AOLIAug 16 2016The Adaptive Optics Lucky Imager, AOLI, is an instrument developed to deliver the highest spatial resolution ever obtained in the visible, 20 mas, from ground-based telescopes. In AOLI a new philosophy of instrumental prototyping has been applied, based ... More
Bona Fide Thermodynamic Temperature in Nonequilibrium Kinetic Ising ModelsAug 08 2003We show that a nominal temperature can be consistently and uniquely defined everywhere in the phase diagram of large classes of nonequilibrium kinetic Ising spin models. In addition, we confirm the recent proposal that, at critical points, the large-time ... More
Critical phenomena of the Majority voter model in a three dimensional cubic latticeAug 31 2012Oct 04 2012In this work we investigate the critical behavior of the three dimensional simple-cubic Majority voter model. Using numerical simulations and a combination of two different cumulants we evaluated the critical point with a higher accuracy than the previous ... More
Tensor interactions and $τ$ decaysJun 14 1995We study the effects of charged tensor weak currents on the strangeness-changing decays of the $\tau$ lepton. First, we use the available information on the $K^+_{e3}$ form factors to obtain BR$(\tau^- \rightarrow K^-\pi^0 \nu_{\tau})\sim {\cal O}(10^{-4})$ ... More
Symplectic and Lie algebraic techniques in Geometric OpticsAug 29 1997We will show the usefulness of the tools of Symplectic and Presymplectic Geometry and the corresponding Lie algebraic methods in different problems in Geometric Optics.
Eutacticity in sea urchin evolutionAug 09 2007An eutactic star, in a n-dimensional space, is a set of N vectors which can be viewed as the projection of N orthogonal vectors in a N-dimensional space. By adequately associating a star of vectors to a particular sea urchin we propose that a measure ... More
Constraining the abundances of complex organics in the inner regions of solar-type protostarsFeb 23 2015The high abundances of Complex Organic Molecules (COMs) with respect to methanol, the most abundant COM, detected towards low-mass protostars, tend to be underpredicted by astrochemical models. This discrepancy might come from the large beam of the single-dish ... More
Procedural Generation of Videos to Train Deep Action Recognition NetworksDec 02 2016Jul 19 2017Deep learning for human action recognition in videos is making significant progress, but is slowed down by its dependency on expensive manual labeling of large video collections. In this work, we investigate the generation of synthetic training data for ... More
Procedural Generation of Videos to Train Deep Action Recognition NetworksDec 02 2016Deep learning for human action recognition in videos is making significant progress, but is slowed down by its dependency on expensive manual labeling of large video collections. In this work, we investigate the generation of synthetic training data for ... More
Next-to-Minimal Supersymmetric Model Higgs Scenarios for Partially Universal GUT Scale Boundary ConditionsMay 06 2011Aug 23 2011We examine the extent to which it is possible to realize the NMSSM "ideal Higgs" models espoused in several papers by Gunion et al in the context of partially universal GUT scale boundary conditions. To this end we use the powerful methodology of nested ... More
Sympathy for the Details: Dense Trajectories and Hybrid Classification Architectures for Action RecognitionAug 25 2016Action recognition in videos is a challenging task due to the complexity of the spatio-temporal patterns to model and the difficulty to acquire and learn on large quantities of video data. Deep learning, although a breakthrough for image classification ... More
Non-constant ponderomotive energy in above threshold ionization by intense short laser pulsesDec 17 2015We analyze the contribution of the quiver kinetic energy acquired by an electron in an oscillating electric field to the energy balance in atomic ionization processes by a short laser pulse. Due to the time dependence of this additional kinetic energy, ... More
Platforms for integrated nonlinear optics compatible with silicon integrated circuitsOct 28 2014Nonlinear photonic chips are capable of generating and processing signals all-optically with performance far superior to that possible electronically - particularly with respect to speed. Although silicon has been the leading platform for nonlinear optics, ... More
Sums of squares in real quadratic fields and Hilbert modular groupsDec 27 2018We use the spectral theory of Hilbert-Maass forms for real quadratic fields to obtain the asymptotics of some sums involving the number of representations as a sum of two squares in the ring of integers.
Data-assimilation by delay-coordinate nudgingOct 27 2015Jan 11 2016A new nudging method for data assimilation, delay-coordinate nudging, is presented. Delay-coordinate nudging makes explicit use of present and past observations in the formulation of the forcing driving the model evolution at each time-step. Numerical ... More
Pulsations in M dwarf starsAug 04 2011Oct 14 2011We present the results of the first theoretical non-radial non-adiabatic pulsational study of M dwarf stellar models with masses in the range 0.1 to 0.5M_solar. We find the fundamental radial mode to be unstable due to an \epsilon mechanism caused by ... More
The normal matrix model with a monomial potential, a vector equilibrium problem, and multiple orthogonal polynomials on a starJan 10 2014Jan 16 2015We investigate the asymptotic behavior of a family of multiple orthogonal polynomials that is naturally linked with the normal matrix model with a monomial potential of arbitrary degree $d+1$. The polynomials that we investigate are multiple orthogonal ... More
Floquet spin states in graphene under ac driven spin-orbit interactionApr 02 2012May 08 2012We study the role of periodically driven time-dependent Rashba spin-orbit coupling (RSOC) on a monolayer graphene sample. After recasting the originally $4\times 4$ system of dynamical equations as two time-reversal related two-level problems, the quasi-energy ... More
Packing unequal rectangles and squares in a fixed size circular container using formulation space searchFeb 21 2018In this paper we formulate the problem of packing unequal rectangles/squares into a fixed size circular container as a mixed-integer nonlinear program. Here we pack rectangles so as to maximise some objective (e.g. maximise the number of rectangles packed ... More
Exciting with Quantum Light. I. Exciting an harmonic oscillatorJan 22 2016Sep 03 2016We start a series of studies of the excitation of an optical target by quantum light. In this first part, we introduce the problematic and address the first case of interest, that of exciting the quantum harmonic oscillator, corresponding to, e.g., a ... More
Statistical modeling of the fluid dual to Boulware-Deser Black holeDec 11 2015Jul 15 2016In this work we study the statistical and thermodynamic properties of the horizon fluid corresponding to the Boulware-Deser (BD) black hole of Einstein-Gauss-Bonnet (EGB) gravity. Using mean field theory, we show explicitly that the BD fluid exhibits ... More
A class of Meijer's G functions and further representations of the generalized hypergeometric functionsJan 26 2018In this paper we investigate the Meijer's $G$ function $G^{p,1}_{p+1,p+1}$ which for certain parameter values represents the Riemann-Liouville fractional integral of Meijer-N{\o}rlund function $G^{p,0}_{p,p}$. Our results for $G^{p,1}_{p+1,p+1}$ include: ... More
MACHETE: A transit Imaging Atmospheric Cherenkov Telescope to survey half of the Very High Energy $γ$-ray skyJul 09 2015Current Imaging Atmospheric Cherenkov Telescopes for Very High Energy $\gamma$-ray astrophysics are pointing instruments with a Field of View up to a few tens of sq deg. We propose to build an array of two non-steerable (drift) telescopes. Each of the ... More
Universal procedure to cure future singularities of dark energy modelsApr 06 2011A systematic search for different viable models of the dark energy universe, all of which give rise to finite-time, future singularities, is undertaken, with the purpose to try to find a solution to this common problem. After some work, a universal procedure ... More
$F_4$ Quantum Integrable, rational and trigonometric models: space-of-orbits viewNov 27 2013Dec 15 2013Algebraic-rational nature of the four-dimensional, $F_4$-invariant integrable quantum Hamiltonians, both rational and trigonometric, is revealed and reviewed. It was shown that being written in $F_4$ Weyl invariants, polynomial and exponential, respectively, ... More
The principle of stationary action in the calculus of variationsMay 04 2012Jan 21 2013We review some techniques from non-linear analysis in order to investigate critical paths for the action functional in the calculus of variations applied to physics. Previous attempts to analyse when these are minima ex- ist, but mainly based on physical ... More
Integration by parts and by substitution unified, Green's Theorem and uniqueness for ODEsMar 19 2015We present a rather unknown version of the change of variables formula for non-autonomous functions. We will show that this formula is equivalent to Green's Theorem for regions of the plane bounded by the graphs of two continuously differentiable functions. ... More
Numerical Solution of the spectral problem for arbitrary self-adjoint extensions of the Schrödinger equation on manifolds with boundaryJun 06 2016A numerical scheme to compute a large class of self-adjoint extensions of the Laplace-Beltrami operator on manifolds with boundary in any dimension is presented. The algorithm is based on the characterisation, recently obtained by the authors, of a large ... More
Adsorption of Self-Assembled Rigid Rods on Two-Dimensional LatticesNov 05 2012Monte Carlo (MC) simulations have been carried out to study the adsorption on square and triangular lattices of particles with two bonding sites that, by decreasing temperature or increasing density, polymerize reversibly into chains with a discrete number ... More
Hydrogen atom in a magnetic field: electromagnetic transitions of the lowest statesNov 16 2007A detailed study of the lowest states $1s_0, 2p_{-1}, 2p_0$ of the hydrogen atom placed in a magnetic field $B\in(0-4.414\times 10^{13} {\rm G})$ and their electromagnetic transitions ($1s_{0} \leftrightarrow 2p_{-1}$ and $ 1s_{0} \leftrightarrow 2p_{0}$) ... More
Hamiltonian analysis for topological and Yang-Mills theories expressed as a constrained BF-like theoryMar 23 2012The Hamiltonian analysis for the Euler and Second-Chern classes is performed. We show that, in spite of the fact that the Second-Chern and Euler invariants give rise to the same equations of motion, their corresponding symplectic structures on the phase ... More
Covariantizing Classical Field TheoriesAug 18 2010We show how to enlarge the covariance group of any classical field theory in such a way that the resulting "covariantized" theory is 'essentially equivalent' to the original. In particular, our technique will render any classical field theory generally ... More
Relaxation, Emission Modes and Limit Temperatures in Ni+Ni HICApr 04 2004A dynamical stability analysis is performed for Ni+Ni central collision at intermediate energies, showing that in chemical, thermal and dynamical equilibriums are reached at an early stage of system evolution. This is obtained by computing the relaxation ... More
The cosmological evolution of the QSO luminosity density and of the star formation rateOct 14 1997We demonstrate that the evolution of the QSO luminosity density with epoch displays a striking similarity to the cosmological evolution of the field galaxy star formation rate, recently derived from a number of independent surveys. The QSO luminosity ... More
Element sets for high-order Poincaré mapping of perturbed Keplerian motionOct 27 2018The propagation and Poincar\'e mapping of perturbed Keplerian motion is a key topic in celestial mechanics and astrodynamics, e.g. to study the stability of orbits or design bounded relative trajectories. The high-order transfer map (HOTM) method enables ... More
A criterion to identify the equilibration time in lipid bilayer simulationsDec 12 2012With the aim of establishing a criterion for identifying when a lipid bilayer has reached steady state using the molecular dynamics simulation technique, lipid bilayers of different composition in their liquid crystalline phase were simulated in aqueous ... More
About the existence of the exotic molecular ions $(HeH)^{2+}$ and $He_2^{3+}$ in a strong magnetic fieldDec 16 2004Oct 29 2006The Coulombic systems $(\al p e)$ and $(\al\al e)$, $(\al p p e)$, $(\al \al p e)$ and $(Li^{3+} Li^{3+} e)$ placed in a magnetic field $B \gtrsim 10^{11} {G}$ are studied. It is demonstrated a theoretical existence of the exotic ion $(He H)^{2+}$ for ... More
Isospin splittings in the light baryon octet from lattice QCD and QEDJun 10 2013Jan 06 2014While electromagnetic and up-down quark mass difference effects on octet baryon masses are very small, they have important consequences. The stability of the hydrogen atom against beta decay is a prominent example. Here we include these effects by adding ... More
Probing the Yang-Mills vacuum with adjoint zero-modesOct 29 2010For the non-perturbative analysis of the topological content of Yang-Mills theories, it is essential to disentangle long-range structures from short-range fluctuations. Some time ago, one of us proposed to use the adjoint modes of the Dirac operator for ... More
Ultraviolet filtering of lattice configurations and applications to Monte Carlo dynamicsMar 30 2011We present a detailed study of a filtering method based upon Dirac quasi-zero-modes in the adjoint representation. The procedure induces no distortions on configurations which are solutions of the euclidean classical equations of motion. On the other ... More
Portosystemic hepatic encephalopathy model shows reversal learning impairment and dysfunction of neural activity in the prefrontal cortex and regions involved in motivated behaviorNov 12 2011Hepatic encephalopathy is a neurological complication that affects attention and memory. Experimental animal models have been used to study hepatic Encephalopathy, the most frequent being the portacaval shunt. In order to determine learning impairment ... More
From confinement to adjoint zero-modesMar 26 2010Starting from our proposed model of the Yang-Mills vacuum based on fractional instantons, we review the intellectual itinerary which has guided part of our scientific activity up to our recent work on adjoint zero-modes for calorons.
Adjoint fermion zero-modes for SU(N) caloronsMay 05 2009We derive analytic formulas for the zero-modes of the Dirac equation in the adjoint representation in the background field of Q=1 SU(N) calorons. Solutions with various boundary conditions are obtained, including the physically most relevant cases of ... More
Adjoint zero-modes as a tool to understand the Yang-Mills vacuumOct 02 2007The use of adjoint (quasi) zero-modes of the Dirac operator to probe the Yangs-Mills vacuum has been recently advocated by Gonzalez-Arroyo and Kirchner. The construction relies on the use of the super-symmetric zero mode which, for classical configurations, ... More
A Gravitational Wave Background from Reheating after Hybrid InflationJul 05 2007Nov 27 2007The reheating of the universe after hybrid inflation proceeds through the nucleation and subsequent collision of large concentrations of energy density in the form of bubble-like structures moving at relativistic speeds. This generates a significant fraction ... More
Is light neutralino as dark matter still viable?Jul 08 2011Motivated by the recent re-confirmation by CoGENT of the low-energy excess of events observed last year, and the recent improved limits from the XENON-100 experiment that are in contention with the CoGENT data, we re-examine the low mass neutralino region ... More
Integral field spectroscopy of HII regions in M33Dec 28 2012Integral field spectroscopy (IFS) is presented for star forming regions in M33. A central area of 300 x 500 pc^2 and the external HII region IC 132, at a galactocentric distance {\sim} 19arcmin (4.69 kpc) were observed with the Potsdam Multi Aperture ... More
Bare Quark Stars or Naked Neutron Stars ? The Case of RX J1856.5-3754Aug 19 2003Nov 21 2003In a cool neutron star (T < 1.e6 K) endowed with a rather high magnetic field (B > 1.e13 G), a phase transition may occur in the outermost layers. As a consequence the neutron star becomes `bare', i.e. no gaseous atmosphere sits on the top of the crust. ... More
Eigenvalues of Hecke operators on Hilbert modular groupsDec 09 2009We consider cuspidal representations in spaces of automorphic forms for the congruence subgroup $\Gamma_0(I)$ of Hilbert modular groups for some number field $F$. To each such representation are associated the eigenvalue $\lambda_j$ of the Casimir operator ... More
A percolation model with continuously varying exponentsJul 28 2015This work analyzes a percolation model on the diamond hierarchical lattice (DHL), where the percolation transition is retarded by the inclusion of a probability of erasing specific connected structures. It has been inspired by the recent interest on the ... More
The Hessenberg matrix and the Riemann mappingJul 29 2011Nov 06 2011We consider a Jordan arc \Gamma in the complex plane \mathbb{C} and a regular measure \mu whose support is \Gamma . We denote by D the upper Hessenberg matrix of the multiplication by z operator with respect to the orthonormal polynomial basis associated ... More
Metrics with good Corona propertiesFeb 11 2015In this note, we give several definitions of metric corona properties which could be of interest in Set Topology, Functional Analysis and Approximation Theory, and prove that there are complete metrizable t.v.s. which are nice in the sense that they have ... More
Finite Hydrogenic molecular chain H$_3$ and ion H$_2^-$ exist in a strong magnetic fieldMar 12 2019The existence and stability of the linear hydrogenic chain H$_3$ and H${}_2^-$ in a strong magnetic field is established. Variational calculations for H$_3$ and H${}_2^-$ are carried out in magnetic fields in the range $10^{11}\leq B \leq 10^{13}\,$G ... More
Implications of Lorentz violation on Higgs-mediated lepton flavor violationAug 14 2014Feb 12 2016The lepton flavor violating decay of the Higgs boson $H\to l_Al_B$ is studied within two qualitatively different extensions of the Yukawa sector: one renormalizable and the other nonrenormalizable; both incorporating Lorentz violation in a model-independent ... More
The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Evolution of the molecular gas in CO-selected galaxiesMar 21 2019We analyze the interstellar medium properties of a sample of sixteen bright CO line emitting galaxies identified in the ALMA Spectroscopic Survey in the Hubble Ultra Deep Field (ASPECS) Large Program. This CO$-$selected galaxy sample is complemented by ... More
The ALMA Spectroscopic Survey in the HUDF: CO emission lines and 3 mm continuum sourcesMar 21 2019The ALMA SPECtroscopic Survey in the {\it Hubble} Ultra Deep Field is an ALMA large program that obtained a frequency scan in the 3\,mm band to detect emission lines from the molecular gas in distant galaxies. We here present our search strategy for emission ... More
Point defect dynamics in bcc metalsNov 27 2004We present an analysis of the time evolution of self-interstitial atom and vacancy (point defect) populations in pure bcc metals under constant irradiation flux conditions. Mean-field rate equations are developed in parallel to a kinetic Monte Carlo (kMC) ... More
On the predictability of Galileo disposal orbitsJan 21 2019The end-of-life disposal of Galileo satellites is needed to avoid collisions with operational spacecraft and to prevent the generation of space debris. Either disposal in stable graveyard orbits or disposal into the atmosphere exploiting eccentricity ... More
Representation equivalence for compact symmetric spaces spaces of real rank oneDec 22 2018Given $G/K$, an irreducible compact symmetric space of {real} rank one, we study conditions on a $K$-type $\tau$ so that $\tau$-isospectrality {between the spaces $\Gamma\backslash G/K$ and $\Gamma'\backslash G/K$} implies that $\Gamma$ and $\Gamma'$ ... More
Strong multiplicity one theorems for locally homogeneous spaces of compact typeApr 23 2018Let $G$ be a compact connected semisimple Lie group, let $K$ be a closed subgroup of $G$, let $\Gamma$ be a finite subgroup of $G$, and let $\tau$ be a finite dimensional representation of $K$. For $\pi$ in the unitary dual $\widehat G$ of $G$, denote ... More
qNoise: A generator of non-Gaussian colored noiseNov 28 2018We introduce a software generator for a class of \emph{colored} (self-correlated) and \emph{non-Gaussian} noise, whose statistics and spectrum depend upon only two parameters, $q$ and $\tau$. Inspired by Tsallis' nonextensive formulation of statistical ... More
Universal Deformation Rings and Quivers of Finite Representation TypeApr 03 2016Let k be a field of arbitrary characteristic and let Q be a quiver of finite representation type. In this paper we prove that if M is an indecomposable kQ-module then the universal deformation ring of M over kQ is isomorphic to k.