Results for "P. M. Arenal"

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HD 51844: An Am delta Scuti in a binary showing periastron brighteningJun 17 2014Pulsating stars in binary systems are ideal laboratories to test stellar evolution and pulsation theory, since a direct, model-independent determination of component masses is possible. The high-precision CoRoT photometry allows a detailed view of the ... More
The World Space Observatory Ultraviolet (WSO-UV), as a bridge to future UV astronomyFeb 19 2018The ultraviolet (UV) astronomy is a very demanded branch of space astronomy. Many dozens of short-term UV-experiments in space, as well as long-term observatories, have brought a very important knowledge on the physics and chemistry of the Universe during ... More
The ASTROID Simulator Software Package: Realistic Modelling of High-Precision High-Cadence Space-Based ImagingFeb 11 2014The preparation of a space-mission that carries out any kind of imaging to detect high-precision low-amplitude variability of its targets requires a robust model for the expected performance of its instruments. This model cannot be derived from simple ... More
Atomic Configuration of Nitrogen Doped Single-Walled Carbon NanotubesJan 20 2014Having access to the chemical environment at the atomic level of a dopant in a nanostructure is crucial for the understanding of its properties. We have performed atomically-resolved electron energy-loss spectroscopy to detect individual nitrogen dopants ... More
Ultraviolet Spectropolarimetry as a Tool for Understanding the Diversity of Exoplanetary AtmospheresMar 14 2019Mar 15 2019The polarization state of starlight reflected by a planetary atmosphere uniquely reveals coverage, particle size, and composition of aerosols as well as changing cloud patterns. It is not possible to obtain a comparable level of detailed from flux-only ... More
Spectroscopic survey of Kepler stars. I. HERMES/Mercator observations of A- and F-type starsMar 12 2015The Kepler space mission provided near-continuous and high-precision photometry of about 207,000 stars, which can be used for asteroseismology. However, for successful seismic modelling it is equally important to have accurate stellar physical parameters. ... More
Two new SB2 binaries with main sequence B-type pulsators in the Kepler fieldApr 08 2013Context: OB stars are important in the chemistry and evolution of the Universe, but the sample of targets well understood from an asteroseismological point of view is still too limited to provide feedback on the current evolutionary models. Our study ... More
Ultraviolet Spectropolarimetry as a Tool for Understanding the Diversity of Exoplanetary AtmospheresMar 14 2019The polarization state of starlight reflected by a planetary atmosphere uniquely reveals coverage, particle size, and composition of aerosols as well as changing cloud patterns. It is not possible to obtain a comparable level of detailed from flux-only ... More
Platinum tripods as nanometric frequency multiplexing devicesJun 26 2018Electrical and structural characterization of nano-particles are very important steps to determine their potential applications in microelectronics. In this paper, we adress the crystallographic and electric transport properties of soft-chemistry-grown ... More
The PLATO Simulator: modelling of high-precision high-cadence space-based imagingApr 07 2014Apr 26 2014Many aspects of the design trade-off of a space-based instrument and its performance can best be tackled through simulations of the expected observations. The complex interplay of various noise sources in the course of the observations make such simulations ... More
Detection of solar-like oscillations in the bright red giant stars $γ$ Psc and $θ^1$ Tau from a 190-day high-precision spectroscopic multisite campaignJul 24 2014Red giants are evolved stars which exhibit solar-like oscillations. Although a multitude of stars have been observed with space telescopes, only a handful of red-giant stars were targets of spectroscopic asteroseismic observing projects. We search for ... More
From hollow gold nanoparticles to gold nanorings: Morphological tunability of the plasmonic responseSep 06 2014The optical and morphological properties of hollow gold nanoparticles (HGNPs) can be finely modified by employing Poly-L-Lysine hydrobromide (PLL), an homo poly aminoacid of the L-lysine, used as reducer and stabilizer. We investigate locally the plasmonic ... More
Pulsating red giant stars in eccentric binary systems discovered from Kepler space-based photometryDec 16 2013The unparalleled photometric data obtained by NASA's Kepler space telescope led to an improved understanding of red giant stars and binary stars. Seismology allows us to constrain the properties of red giants. In addition to eclipsing binaries, eccentric ... More
The PLATO 2.0 MissionOct 02 2013Mar 04 2014PLATO 2.0 has recently been selected for ESA's M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental questions such as: How do planetary systems form ... More
WUVS Simulator: Detectability of spectral lines with the WSO-UV spectrographsJun 08 2017Jun 12 2017The World Space Observatory - Ultraviolet (WSO-UV) space telescope is equipped with high dispersion (55,000) spectrographs working in the 1150-3100 {\AA} spectral range. To evaluate the impact of the design on the scientific objectives of the mission, ... More
Oxidation-assisted graphene heteroepitaxy on copper foilSep 09 2016We propose an innovative, easy-to-implement approach to synthesize large-area singlecrystalline graphene sheets by chemical vapor deposition on copper foil. This method doubly takes advantage of residual oxygen present in the gas phase. First, by slightly ... More
Insights into the High Temperature Superconducting Cuprates from Resonant Inelastic X-ray ScatteringFeb 21 2014Apr 04 2014Recent improvements in instrumentation have established resonant inelastic x-ray scattering (RIXS) as a valuable new probe of the magnetic excitations in the cuprates. This article introduces RIXS, focusing on the Cu $L_3$ resonance, and reviews recent ... More
Structure of the conservation laws in integrable spin chains with short range interactionsNov 07 1994We present a detailed analysis of the structure of the conservation laws in quantum integrable chains of the XYZ-type and in the Hubbard model. With the use of the boost operator, we establish the general form of the XYZ conserved charges in terms of ... More
The Structure of Conserved Charges in Open Spin ChainsApr 15 1996Sep 13 1996We study the local conserved charges in integrable spin chains of the XYZ type with nontrivial boundary conditions. The general structure of these charges consists of a bulk part, whose density is identical to that of a periodic chain, and a boundary ... More
Quantum group covariant systemsDec 20 1995The meaning of quantum group transformation properties is discussed in some detail by comparing the (co)actions of the quantum group with those of the corresponding Lie group, both of which have the same algebraic (matrix) form of the transformation. ... More
One-Parameter Scaling of the Conductivity of Si:B: A Temperature-Independent Variable-Range Hopping PrefactorSep 12 2001For insulating Si:B with dopant concentrations from 0.75 n_c to the critical concentration n_c, the conductivity ranging over five orders of magnitude collapses using a single scaling parameter T* onto a universal curve of the form $\sigma (T) =\sigma_0 ... More
Coupled study by TEM/EELS and STM/STS of electronic properties of C- and CNx-nanotubesOct 12 2011Carbon nanotubes are the focus of considerable research efforts due to their fascinating physical properties. They provide an excellent model system for the study of one dimensional materials and molecular electronics. The chirality of nanotubes can lead ... More
Examining subgrid models of supermassive black holes in cosmological simulationJun 15 2010Oct 07 2010While supermassive black holes (SMBHs) play an important role in galaxy and cluster evolution, at present they can only be included in large-scale cosmological simulation via subgrid techniques. However, these subgrid models have not been studied in a ... More
Magnetization screening from gluonic currents and scaling law violation in the ratio of magnetic form factors for neutron and protonJun 24 2003The ratio ${\mu_p}G_E^p/G_M^p$ exhibits a decrease for four-momentum transfer Q^2 increasing beyond 1 GeV^2 indicating different spatial distributions for charge and for magnetization inside the proton. One-gluon exchange currents can explain this behaviour. ... More
Resolution of the lambda Phi^4 Puzzle and a 2 Tev Higgs BosonMar 14 1993Aug 03 1993We argue that massless (lambda Phi^4)_4 is "trivial" without being entirely trivial. It has a non-trivial effective potential which leads to spontaneous symmetry breaking, but the particle excitations above the broken vacuum are non-interacting. The key ... More
Momentum dependent relaxation rate and pseudogap in doped magnetic insulatorsAug 14 2006The spectral functions and corresponding self energies are calculated within the planar t-t'-J model as relevant to hole-doped cuprates using the exact diagonalization method at finite temperatures, combined with the averaging over twisted boundary conditions. ... More
Even and odd geometries on supermanifoldsMay 15 2008We analyze from a general perspective all possible supersymmetric generalizations of symplectic and metric structures on smooth manifolds. There are two different types of structures according to the even/odd character of the corresponding quadratic tensors. ... More
On the Piecewise Parabolic Method for Compressible Flow with Stellar Equations of StateJan 08 2015The piecewise parabolic method and related schemes are widely used to model stellar flows. Several different methods for extending the validity of these methods to a general equation of state have been proposed over time, but direct comparisons amongst ... More
Renormalization of the Majorana bound state decay length in a perpendicular magnetic fieldNov 17 2017Jan 12 2018Orbital effects of a magnetic field in a proximitized semiconductor nanowire are studied in the context of the spatial extent of Majorana bound states. We develop analytical model that explains the impact of concurring effects of paramagnetic coupling ... More
Dispersion-managed soliton in a strong dispersion map limitMar 26 2001A dispersion-managed optical system with step-wise periodical variation of dispersion is studied in a strong dispersion map limit in the framework of path-averaged Gabitov-Turitsyn equation. The soliton solution is obtained by iterating the path-averaged ... More
Fully parallel algorithm for simulating dispersion-managed wavelength-division-multiplexed optical fiber systemsFeb 23 2002An efficient numerical algorithm is presented for massively parallel simulations of dispersion-managed wavelength-division-multiplexed optical fiber systems. The algorithm is based on a weak nonlinearity approximation and independent parallel calculations ... More
Dynamical description of heavy-ion collisions at Fermi energiesSep 28 2015Descriptions of heavy-ion collisions at Fermi energies require to take into account in-medium dissipation and phase-space fluctuations. The interplay of these correlations with the one-body collective behaviour determines the properties (kinematics and ... More
KH15D: a star eclipsed by a large scale dusty vortex?Jul 18 2003We propose that the large photometric variations of KH15D are due to an eclipsing swarm of solid particles trapped in giant gaseous vortex rotating at \~0.2 AU from the star. The efficiency of the capture-in-vortex mechanism easily explains the observed ... More
Acoustic horizons for axially and spherically symmetric fluid flowOct 18 2005We investigate the formation of acoustic horizons for an inviscid fluid moving in a pipe in the case of stationary and axi-symmetric flow. We show that, differently from what is generally believed, the acoustic horizon forms in correspondence of either ... More
Competition between relaxation and external driving in the dissipative Landau-Zener problemMay 07 2012We study Landau-Zener transitions in a dissipative environment by means of the quasiadiabatic propagator path-integral scheme. It allows to obtain numerically exact results for the full range of the involved parameters. We discover a nonmonotonic dependence ... More
Ultraslow quantum dynamics in a sub-Ohmic heat bathAug 19 2009May 12 2010We show that the low-frequency modes of a sub-Ohmic bosonic heat bath generate an effective dynamical asymmetry for an intrinsically symmetric quantum spin -1/2. An initially fully polarized spin first decays towards a quasiequilibrium determined by the ... More
A remark on the spectrum of the analytic generatorApr 28 2006It is shown that although the spectrum of the analytic generator of a one--parameter group of isometries of a Banach space may be equal to the whole complex plane, a simple operation of ampliating the analytic generator onto its graph locates its spectrum ... More
Calculation of minor hysteresis loops under metastable to stable transformations in vortex matterAug 29 2000We present a model in which metastable supercooled phase and stable equilibrium phase of vortex matter coexist in different regions of a sample. Minor hysteresis loops are calculated with the simple assumption of the two phases of vortex matter having ... More
Dust-driven Dynamos in Accretion DisksJul 09 2008Magnetically driven astrophysical jets are related to accretion and involve toroidal magnetic field pressure inflating poloidal magnetic field flux surfaces. Examination of particle motion in combined gravitational and magnetic fields shows that these ... More
On the influence of blends on the potential of ground-based transit surveysJan 22 2007Transit surveys have to observe many stars all at once in order to compensate for the rarity of the searched events. Such surveys, especially the ones observing a deep field of view and/or broadening their stellar images, have to deal with a relatively ... More
Chaotic dot-superconductor analog of the Hanbury Brown Twiss effectMar 08 2002As an electrical analog of the optical Hanbury Brown Twiss effect, we study current cross-correlations in a chaotic quantum dot-superconductor junction. One superconducting and two normal reservoirs are connected via point contacts to a chaotic quantum ... More
Sums of permanental minors using Grassmann algebraJun 20 2014We show that a formalism proposed by Creutz to evaluate Grassmann integrals provides an algorithm of complexity $O(2^n n^3)$ to compute the generating function for the sum of the permanental minors of a matrix of order $n$. This algorithm improves over ... More
Off-Center Collisions between Clusters of GalaxiesOct 15 1997We present numerical simulations of off-center collisions between galaxy clusters made using a new hydrodynamical code based on the piecewise-parabolic method (PPM) and an isolated multigrid Poisson solver. We have performed three gas-only high-resolution ... More
Extension to order $β^{23}$ of the high-temperature expansions for the spin-1/2 Ising model on the simple-cubic and the body-centered-cubic latticesJun 06 2000Nov 07 2000Using a renormalized linked-cluster-expansion method, we have extended to order $\beta^{23}$ the high-temperature series for the susceptibility $\chi$ and the second-moment correlation length $\xi$ of the spin-1/2 Ising models on the sc and the bcc lattices. ... More
A library of extended high-temperature expansions of basic observables for the spin S Ising models on two- and three-dimensional latticesApr 05 2002We present an on-line library of unprecedented extension for high-temperature expansions of basic observables in the Ising models of general spin S, with nearest-neighbor interactions. We have tabulated through order beta^{25} the series for the nearest-neighbor ... More
A remark on the numerical validation of triviality for scalar field theories using high-temperature expansionsDec 23 2001We suggest a simple modification of the usual procedures of analysis for the high-temperature (strong-coupling or hopping-parameter) expansions of the renormalized four-point coupling constant in the fourdimensional phi^4 lattice scalar field theory. ... More
N-vector spin models on the sc and the bcc lattices: a study of the critical behavior of the susceptibility and of the correlation length by high temperature series extended to order beta^{21}Mar 26 1997Jul 16 1997High temperature expansions for the free energy, the susceptibility and the second correlation moment of the classical N-vector model [also known as the O(N) symmetric classical spin Heisenberg model or as the lattice O(N) nonlinear sigma model] on the ... More
New extended high temperature series for the N-vector spin models on three-dimensional bipartite latticesMay 31 1995High temperature expansions for the susceptibility and the second correlation moment of the classical N-vector model (O(N) symmetric Heisenberg model) on the sc and the bcc lattices are extended to order $\beta^{19}$ for arbitrary N. For N= 2,3,4.. we ... More
Effective degrees of freedom of the Quark-Gluon PlasmaOct 26 2005The effective degrees of freedom of the Quark-Gluon Plasma are studied in the temperature range $\sim 1-2$ $ T_c$. Employing lattice results for the pressure and the energy density, we constrain the quasiparticle chiral invariant mass to be of order 200 ... More
Extreme Starbursts and Molecular Clouds in GalaxiesJan 26 2001The extraordinary starbursts found in ultraluminous IR galaxies occur in molecular gas concentrated in compact very massive "clouds" which we call "Extreme Starbursts". They have one thousand times the mass but are only a few times larger than GMCs. High-mass ... More
Surface properties of nuclear pairing with the Gogny force in a simplified modelApr 06 1999Surface properties of neutron-neutron (T=1) pairing in semi-infinite nuclear matter in a hard wall potential are investigated in BCS approximation using the Gogny force. Surface enhancement of the gap function, pairing tensor and correlation energy density ... More
Short time die attach characterisation of semiconductor devicesJan 07 2008Thermal qualification of the die attach of semiconductor devices is a very important element in the device characterization as the temperature of the chip is strongly affected by the quality of the die attach. Voids or delaminations in this layer may ... More
Experimental Proof of the Existence of a Bifurcation Process During the undrained test in ClayJul 05 2005Recent papers, based on a new simple incremental modelling which assumes an "isotropic" response, predicts that the trajectory followed during an undrained compression test exhibits a bifurcation process when the stress field arrives at q=M'p', where ... More
Tackling the Gross-Pitaevskii energy functional with the Sobolev gradient - Analytical and numerical resultsJun 17 2009In the first part of this contribution we prove the global existence and uniqueness of a trajectory that globally converges to the minimizer of the Gross-Pitaevskii energy functional for a large class of external potentials. Using the method of Sobolev ... More
Secure Digital Signal Transmission by Multistep Parameter Modulation and Alternative Driving of Transmitter VariablesNov 03 2000The idea of secure communication of digital signals via chaos synchronization has been plagued by the possibility of attractor reconstruction by eavesdroppers as pointed out by Perez and Cerdeira. In this Letter, we wish to present a very simple mechanism ... More
Spontaneous spin current due to triplet superconductor--ferromagnet interfacesAug 27 2009Dec 23 2009We examine the appearance of a spontaneous bulk spin current in a triplet superconductor in contact with a metallic ferromagnet. The spin current results from the spin-flip of Cooper pairs upon reflection from the interface with the ferromagnet, and is ... More
Modeling transitional plane Couette flowNov 22 2008The Galerkin method is used to derive a realistic model of plane Couette flow in terms of partial differential equations governing the space-time dependence of the amplitude of a few cross-stream modes. Numerical simulations show that it reproduces the ... More
Clusters as benchmarks for measuring fundamental stellar parametersSep 11 2016In this contribution I will discuss fundamental stellar parameters as determined from young star clusters; specifically those with ages less than or approximately equal to that of the Pleiades. I will focus primarily on the use of stellar evolutionary ... More
Anomalous dynamics of confined water at low hydrationNov 12 2003The mobility of water molecules confined in a silica pore is studied by computer simulation in the low hydration regime, where most of the molecules reside close to the hydrophilic substrate. A layer analysis of the single particle dynamics of these molecules ... More
Comment about pion electro-production and the axial form factorsDec 12 2000The claim by Haberzettl (Phys.Rev.Lett.85 (2000) 3576) that the axial form factor of the nucleon cannot be accessed through threshold pion electroproduction is unfounded.
The statistical properties of the city transport in Cuernavaca (Mexico) and Random matrix ensemblesJan 11 2000We analyze statistical properties of the city bus transport in Cuernavaca (Mexico) and show that the bus arrivals display probability distributions conforming those given by the Unitary Ensemble of random matrices.
Spin-orbit entanglement in time evolution of radial wave packets in hydrogenic systemsApr 14 2004Time evolution of radial wave packets built from the eigenstates of Dirac equation for a hydrogenic systems is considered. Radial wave packets are constructed from the states of different $n$ quantum number and the same lowest angular momentum. In general ... More
Dwarf-spheroidal satellites: are they of tidal origin?Jan 10 2007The Milky Way and Andromeda must have formed through an initial epoch of sub-structure merging. As a result of fundamental physical conservation laws tidal-dwarf galaxies (TDGs) have likely been produced. Here we show that such TDGs appear, after a Hubble-time ... More
Extragalactic 2-10 keV source counts from a fluctuation analysis of deep BeppoSAX MECS imagesJun 21 2000We present an analysis of the spatial fluctuations of the 2-10 keV Cosmic X-ray Background (CXB) as measured from 22 high galactic latitude (|b| > 25 deg) fields observed with the MECS instrument on-board BeppoSAX. This technique allowed us to probe extragalactic ... More
Covariant Non-local Chiral Quark Model and Pion-photon Transition Distribution AmplitudesJul 23 2009Jul 30 2009Using non-local chiral quark model with simple pole ansatz for mass dependence on momentum and non-local currents satisfying Ward-Takahashi identities, we calculate pion to photon transition distribution amplitudes and relevant form factors. For vector ... More
Elastic Scattering of Neutrinos off Polarized ElectronsJan 25 2002We calculate the cross sections for elastic nu_l + e -> nu_l + e and antinu_l + e -> antinu_l + e scattering (l=e, mu or tau) in the Born approximation and with exactly fixed polarization states of target and final-state electrons, discussing their sensitivity ... More
Milagro Search for VHE Emission from GRBs in the Swift EraNov 14 2006Since its launch, in late 2004, Swift has been locating gamma-ray bursts (GRBs) at a rate of $\sim$100 per year. The rapid localization and follow-up in many wavelengths is providing new insights and revealing new, and unexpected phenomena, such as bright ... More
Milagro Search for Very High Energy Emission from Gamma-Ray Bursts in the Swift EraFeb 08 2006The recently launched Swift satellite is providing an unprecedented number of rapid and accurate Gamma-Ray Burst (GRB) localizations, facilitating a flurry of follow-up observations by a large number of telescopes at many different wavelengths. The Very ... More
The Accretion-Ejection Instability in X-ray BinariesNov 13 2000The Accretion-Ejection Instability (AEI), which can occur in magnetized disks near equipartition, is a good candidate to explain the low-frequency QPO in black-hole binaries. Here we present analytical work concerning the behavior of QPO frequency and ... More
Hydrogen-induced ferromagnetism in ZnO single crystals investigated by MagnetotransportJun 24 2011We investigated the electrical and magnetic properties of low-energy hydrogen-implanted ZnO single crystals with hydrogen concentrations up to 3 at.% in the first 20 nm surface layer between 10 K and 300 K. All samples showed clear ferromagnetic hysteresis ... More
Thermal diffusion in the IGM of clusters of galaxiesSep 25 2009We revisit the phenomenon of elements diffusion in the intergalactic medium (IGM) in clusters of galaxies. The diffusion is driven by gravity, concentration and temperature gradients. The latter cause thermal diffusion, which has been so far ignored in ... More
The first analysis of extragalactic binary-orbit precessionNov 12 2013The main aim of the present paper is the very first analysis of the binary-orbit precession out of our Galaxy. The light curves of an eclipsing binary MACHO 82.8043.171 in the Large Magellanic cloud (LMC) were studied in order to analyse the long-term ... More
Successive Umbrella SamplingJun 26 2003We propose an extension of umbrella sampling in which the pertinent range of states is subdivided in windows that are sampled consecutively and linked together. Extrapolating results from one window we estimate a weight function for the neighboring window. ... More
Twistor--like Formulation of D=10, type IIA, Superstrings $^*$May 11 1994The twistor--like formulation of the type IIA superstring $\sigma$--model in D=10 is obtained by performing a dimensional reduction of the recently proposed twistor--like action of the supermembrane in D=11. The superstring action is invariant under local, ... More
$q$-Virasoro Algebra and the Point-SplittingMar 11 1996It is shown that a particular $q$-deformation of the Virasoro algebra can be interpreted in terms of the $q$-local field $\Phi (x)$ and the Schwinger-like point-splitted Virasoro currents, quadratic in $\Phi (x)$. The $q$-deformed Virasoro algebra possesses ... More
Measurement of the eta->pi+pi-pi0 decay with WASA-at-COSY detectorSep 28 2010One of the objectives of the physics programme of the WASA-at-COSY facility is to study the isospin violating eta hadronic decays into pi+pi-pi0$ systems driven by the term of QCD Lagrangian which depends on the d and u quark mass difference. These studies ... More
The Formation of Ultra-Compact Dwarf GalaxiesOct 29 2001Recent spectroscopic observations of galaxies in the Fornax-Cluster reveal nearly unresolved `star-like' objects with red-shifts appropriate to the Fornax-Cluster. These objects have intrinsic sizes of about 100 pc and absolute B-band magnitudes in the ... More
Dynamics of ion cloud in a linear Paul trapJun 24 2013A linear ion trap setup has been developed for studying the dynamics of trapped ion cloud and thereby realizing possible systematics of a high precision measurement on a single ion within it. The dynamics of molecular nitrogen ion cloud has been investigated ... More
Field induced metamagnetic transitions in quasi-one-dimensional Ising spin chain CoV$_{2}$O$_{6}$Aug 10 2015We have investigated the temperature and magnetic field dependence of magnetization ($M$), specific heat ($C_p$), and relative sample length change ($\Delta L/L_0$) for understanding the field-induced metamagnetic transitions in quasi-one-dimensional ... More
Air-guiding photonic bandgap fiber with improved triangular air-silica photonic crystal claddingOct 25 2005Oct 29 2005We introduce a small-core air-guiding photonic crystal fiber whose cladding is made of improved air-silica photonic crystal with non-circular air holes placed in triangular lattice. The fiber achieves un-disturbed bandgap guidance over 350nm wavelength ... More
Complex Electronic Behavior in a 1D Correlated Quantum LiquidAug 05 2005The relation of the rotated-electron site distribution configurations that describe the energy eigenstates of the one-dimensional Hubbard model to the momentum occupancy configurations of the same states associated with the Bethe ansatz quantum numbers ... More
Combining Information from $B \to ππ$ and $B \to πρ, π ω$ DecaysFeb 03 2005May 30 2005We consider the $B \to \pi \pi $ and $B \to \pi \rho, \pi \omega $ decays alongside each other, taking into account the contributions from all individual penguin amplitudes generated by the internal $t$, $c$, and $u$ quarks. We argue that three ratios ... More
Paramagnetism, zero modes and mass singularities in QED in $1+1$, $2+1$ and $3+1$ dimensionsNov 08 1996The interplay of paramagnetism, zero modes of the Dirac operator and fermionic mass singularities on the fermionic determinants in quantum electrodynamics in two, three and four dimensions is discussed.
Fermion Determinants in Static, Inhomogeneous Magnetic FieldsOct 18 1994The renormalized fermionic determinant of QED in 3 + 1 dimensions, $\mbox{det}_{{ren}}$, in a static, unidirectional, inhomogeneous magnetic field with finite flux can be calculated from the massive Euclidean Schwinger model's determinant, $\mbox{det}_{{Sch}}$, ... More
Fermion DeterminantsNov 27 2001The current status of bounds on and limits of fermion determinants in two, three and four dimensions in QED and QCD is reviewed. A new lower bound on the two-dimensional QED determinant is derived. An outline of the demonstration of the continuity of ... More
Signature of nearly icosahedral structures in liquid and supercooled liquid CopperFeb 09 2006Jul 26 2006A growing body of experiments display indirect evidence of icosahedral structures in supercooled liquid metals. Computer simulations provide more direct evidence but generally rely on approximate interatomic potentials of unproven accuracy. We use first-principles ... More
On geometric perturbations of critical Schrödinger operators with a surface interactionJan 09 2009We study singular Schrodinger operators with an attractive interaction supported by a closed smooth surface A in R^3 and analyze their behavior in the vicinity of the critical situation where such an operator has empty discrete spectrum and a threshold ... More
Symmetric Spaces and Star representations II : Causal Symmetric SpacesMay 08 2001We construct and identify star representations canonically associated with holonomy reducible simple symplectic symmetric spaces. This leads the a non-commutative geometric realization of the correspondence between causal symmetric spaces of Cayley type ... More
Symmetric Spaces and star representations III. The Poincare DiskSep 17 2002This article is a contribution to the domain of (convergent) deformation quantization of symmetric spaces by use of Lie groups representation theory. We realize the regular representation of $SL(2,\R)$ on the space of smooth functions on the Poincar\'e ... More
E-theory for C[0,1]-algebras with finitely many singular pointsSep 03 2013Dec 15 2013We study the E-theory group $E_{[0,1]}(A,B)$ for a class of C*-algebras over the unit interval with finitely many singular points, called elementary $C[0,1]$-algebras. We use results on E-theory over non-Hausdorff spaces to describe $E_{[0,1]}(A,B)$ where ... More
Optimization for factorized quantities in perturbative QCDApr 15 2019Perturbative calculations of factorized physical quantities, such as moments of structure functions, suffer from renormalization- and factorization-scheme dependence. The application of the principle of minimal sensitivity to "optimize" the scheme choices ... More
(Semi)continuity of the entropy of Sinai probability measures for partially hyperbolic diffeomorphismsApr 28 2015We establish sufficient conditions for the upper semicontinuity and the continuity of the entropy of Sinai probability measures invariant by partially hyperbolic diffeomorphisms and discuss their application in several examples.
Tight frame completions with prescribed normsJun 13 2006Let $\hil$ be a finite dimensional (real or complex) Hilbert space and let $\{a_i\}_{i=1}^\infty$ be a non-increasing sequence of positive numbers. Given a finite sequence of vectors $\f$ in $\hil$ we find necessary and sufficient conditions for the existence ... More
$2$- capability and $2$- nilpotent multiplier of finite dimensional nilpotent Lie algebrasOct 18 2016Nov 08 2016In the present context, we investigate to obtain some more results about $2$-nilpotent multiplier $\mathcal{M}^{(2)}(L)$ of a finite dimensional nilpotent Lie algebra $L$. For instance, we characterize the structure of $\mathcal{M}^{(2)}(H)$ when $H$ ... More
Conditional-sum-of-squares estimation of models for stationary time series with long memoryFeb 26 2007Employing recent results of Robinson (2005) we consider the asymptotic properties of conditional-sum-of-squares (CSS) estimates of parametric models for stationary time series with long memory. CSS estimation has been considered as a rival to Gaussian ... More
Classification of $p$-groups via their $2$-nilpotent multipliersDec 01 2018For a $p$-group of order $p^n$, it is known that the order of $2$-nilpotent multiplier is equal to $|\mathcal{M}^{(2)}(G)|=p^{\f12n(n-1)(n-2)+3-s_2(G)}$ for an integer $s_2(G)$. In this article, we characterize all of non abelian $p$-groups satisfying ... More
Bifurcation of free vibrations for completely resonant wave equationsSep 03 2004We prove existence of small amplitude, 2 pi/omega -periodic in time solutions of completely resonant nonlinear wave equations with Dirichlet boundary conditions for any frequency omega belonging to a Cantor-like set of positive measure and for a generic ... More
Turing Kernelization for Finding Long Paths and Cycles in Restricted Graph ClassesFeb 19 2014Jan 29 2016The NP-complete $k$-Path problem asks whether a given undirected graph has a (simple) path of length at least $k$. We prove that $k$-Path has polynomial-size Turing kernels when restricted to planar graphs, graphs of bounded degree, claw-free graphs, ... More
Lagrange formalism of point-massesMay 27 2002We prove by symmetry properties that the Lagrangian of a free point-mass is a quadratic function of the speed in the non-relativistic case, and that the action of the free point-mass between two spacetime points is the proper time passed in the relativistic ... More
Direct integrals and spectral averagingNov 08 2010A one parameter family of selfadjoint operators gives rise to a corresponding direct integral. We show how to use the Putnam Kato theorem to obtain a new method for the proof of a spectral averaging result.