Results for "D. W. Nychka"

total 168817took 0.11s
A Few Results about the Geometry of Model AveragesMay 23 2008Jul 10 2008Given a collection of computational models that all estimate values of the same natural process, we compare the performance of the average of the collection to the individual member whose estimates are nearest a given set of observations. Performance ... More
ROAM: a Radial-basis-function Optimization Approximation Method for diagnosing the three-dimensional coronal magnetic fieldJul 12 2016The Coronal Multichannel Polarimeter (CoMP) routinely performs coronal polarimetric measurements using the Fe XIII 10747 $\AA$ and 10798 $\AA$ lines, which are sensitive to the coronal magnetic field. However, inverting such polarimetric measurements ... More
Data-Optimized Coronal Field Model: I. Proof of ConceptApr 12 2019Deriving the strength and direction of the three-dimensional (3D) magnetic field in the solar atmosphere is fundamental for understanding its dynamics. Volume information on the magnetic field mostly relies on coupling 3D reconstruction methods with photospheric ... More
Estimating Precipitation Extremes using Log-HistosplineFeb 26 2018Oct 04 2018One of the commonly used approaches to modeling extremes is the peaks-over-threshold (POT) method. The POT method models exceedances over a threshold that is sufficiently high or low so that the exceedance has approximately a generalized Pareto distribution ... More
A Multiresolution Census Algorithm for Calculating Vortex Statistics in Turbulent FlowsOct 02 2007The fundamental equations that model turbulent flow do not provide much insight into the size and shape of observed turbulent structures. We investigate the efficient and accurate representation of structures in two-dimensional turbulence by applying ... More
Discussion of: A statistical analysis of multiple temperature proxies: Are reconstructions of surface temperatures over the last 1000 years reliable?May 03 2011Discussion of "A statistical analysis of multiple temperature proxies: Are reconstructions of surface temperatures over the last 1000 years reliable?" by B.B. McShane and A.J. Wyner [arXiv:1104.4002]
Parameter estimation for computationally intensive nonlinear regression with an application to climate modelingJan 23 2009Nonlinear regression is a useful statistical tool, relating observed data and a nonlinear function of unknown parameters. When the parameter-dependent nonlinear function is computationally intensive, a straightforward regression analysis by maximum likelihood ... More
A Case Study Competition Among Methods for Analyzing Large Spatial DataOct 13 2017Apr 25 2018The Gaussian process is an indispensable tool for spatial data analysts. The onset of the "big data" era, however, has lead to the traditional Gaussian process being computationally infeasible for modern spatial data. As such, various alternatives to ... More
Methods for Analyzing Large Spatial Data: A Review and ComparisonOct 13 2017The Gaussian process is an indispensable tool for spatial data analysts. The onset of the "big data" era, however, has lead to the traditional Gaussian process being computationally infeasible for modern spatial data. As such, various alternatives to ... More
Reduced Basis Kriging for Big Spatial FieldsFeb 23 2018Apr 25 2018In spatial statistics, a common method for prediction over a Gaussian random field (GRF) is maximum likelihood estimation combined with kriging. For massive data sets, kriging is computationally intensive, both in terms of CPU time and memory, and so ... More
Interpolating fields of carbon monoxide data using a hybrid statistical-physical modelJan 23 2009Atmospheric Carbon Monoxide (CO) provides a window on the chemistry of the atmosphere since it is one of few chemical constituents that can be remotely sensed, and it can be used to determine budgets of other greenhouse gases such as ozone and OH radicals. ... More
On the Interaction Between Cosmic Rays and Dark Matter Molecular Clouds - II. The Age Distribution of Cosmic Ray ElectronsSep 14 1999We explore further the proposal in paper I of this series that the confinement time of cosmic ray nuclei in the Milky Way is determined by their interaction with dark matter molecular clouds rather than by their escape from the halo, as is assumed in ... More
Decaying Neutrinos and the Flattening of the Galactic HaloApr 10 1997The recently constructed Dehnen-Binney set of mass models for the Galaxy is used to show that the decaying neutrino theory for the ionisation of the interstellar medium (Sciama 1990a, 1993) requires the neutrino halo of the Galaxy to be as flattened as ... More
T-Odd Triple-Product Correlations in Hadronic b DecaysMay 02 2000We study T-violating triple-product asymmetries in the quark-level decay b -> s u u(bar) within the standard model (SM). We find that only two types of triple products are non-negligible. The asymmetry in p_u . [s_u x s_u(bar)] or p_u(bar) . [s_u x s_u(bar)] ... More
FansJan 11 2016The category of (abstract) fans is to the category of monoids what the category of schemes is to the category of rings: a fan is obtained by gluing spectra of monoids along open embeddings. Here we study the basic algebraic geometry of fans: coherent ... More
The strange quark condensate in the nucleon in 2+1 flavor QCDMay 14 2009Sep 14 2009We calculate the "strange quark content of the nucleon", <N| s s_bar |N>, which is important for interpreting the results of some dark matter detection experiments. The method is to evaluate quark-line disconnected correlations on the MILC lattice ensembles, ... More
Ferromagnetism in the Periodic Anderson Model: A Comparison of Spectral Density Approximation (SDA), Modified Alloy Analogy (MAA) and Modified Perturbation Theory (MPT)Aug 30 2000We compare different approximation schemes for investigating ferromagnetism in the periodic Anderson model. The use of several approximations allows for a detailed analysis of the implications of the respective methods, and also of the mechanisms driving ... More
How to approach Quantum Gravity - Background independence in 1+1 dimensionsOct 14 2003Oct 17 2003The application of quantum theory to gravity is beset with many technical and conceptual problems. After a short tour d'horizon of recent attempts to master those problems by the introduction of new approaches, we show that the aim, a background independent ... More
Some recent results for the roAp starsMay 05 1998Three topics are discussed: 1) Photometric observations of the rapidly oscillating Ap stars have shown that the pulsation amplitude drops dramatically as a function of wavelength from the blue to the red. A theoretical derivation, plus modelling, indicates ... More
Ising and Potts Models on Quenched Random Gravity GraphsJul 29 1999We report on single-cluster Monte Carlo simulations of the Ising, 4-state Potts and 10-state Potts models on quenched ensembles of planar, tri-valent random graphs. We confirm that the first-order phase transition of the 10-state Potts model on regular ... More
Quantum Vernam CipherDec 15 2000Oct 09 2001We discuss aspects of secure quantum communication by proposing and analyzing a quantum analog of the Vernam cipher (one-time-pad). The quantum Vernam cipher uses entanglement as the key to encrypt quantum information sent through an insecure quantum ... More
The Quantum Boltzmann Equation in Semiconductor PhysicsNov 16 2010The quantum Boltzmann equation, or Fokker-Planck equation, has been used to successfully explain a number of experiments in semiconductor optics in the past two decades. This paper reviews some of the developments of this work, including models of excitons ... More
IR Renormalisation of General Effective Actions and Hawking Flux in 2D Gravity TheoriesDec 29 2005The infrared problem of the effective action in 2D is discussed in the framework of the Covariant Perturbation Theory. The divergences are regularised by a mass and the leading term is evaluated up to the third order of perturbation theory. A summation ... More
The Scalar Quarkonium Spectrum and Quarkonium-Glueball MixingJan 14 1998We evaluate the valence approximation to the mass of scalar quarkonium and to the mixing energy between scalar quarkonium and the lightest scalar glueball for a range of different lattice sizes and quark masses. Our results support the identification ... More
Scales and the fine structure of K(R). Part II: Weak real mice and scalesMay 16 2006May 16 2006We define weak real mice $\mathcal{M}$ and prove that the boldface pointclass $\boldsymbol{\Sigma}_m(\mathcal{M})$ has the scale property assuming only the determinacy of sets of reals in $\mathcal{M}$ when $m$ is the smallest integer $m>0$ such that ... More
Reply to Boglione and PenningtonApr 24 2000In a recent article we presented an argument which, we believe, shows to be incorrect an estimate, by Boglione and Pennington, of corrections to the valence (quenched) approximation predictions for properties of the lightest scalar glueball. Boglione ... More
A stable partitioned FSI algorithm for incompressible flow and structural shellsAug 27 2013A stable partitioned algorithm for fluid-structure interaction (FSI) problems that couple viscous incompressible flow with structural shells or beams is described. This added-mass partitioned (AMP) scheme uses Robin (mixed) interface conditions for the ... More
Radio Spectra of three Supernova Remnants: G114.3+0.3, G116.5+1.1 and G116.9+0.2Nov 10 2005Oct 12 2006New images of the Supernova Remnants (SNRs) G114.3+0.3, G116.5+1.1 and G116.9+0.2 (CTB 1) are presented at 408 MHz from the Canadian Galactic Plane Survey (CGPS). We also use the 1420 MHz images from the CGPS to study their 408-1420 MHz spectral indices. ... More
Precision Measurements of the Proton Elastic Form Factor RatioJan 19 2010Jan 23 2010New high precision polarization measurements of the proton elastic form factor ratio in the Q^2 range from 0.3 to 0.7 [GeV/c]^2 have been made. These elastic H(e,e'p) measurements were done in Jefferson Lab's Hall A using 80% longitudinally polarized ... More
Updated Parameters for the Decaying Neutrino Theory and EURD Observations of the Diffuse UV BackgroundSep 25 1997May 13 1998Various recent observational developments are here used to make a more critical analysis of the parameter space of the decaying neutrino theory for the ionisation of the interstellar medium. These developments involve phenomena inside our Galaxy, outside ... More
An updated precision estimate of the Hubble constant and the age and density of the Universe in the decaying neutrino theoryMar 11 1997We here update the derivation of precise values for the Hubble constant H_0, the age t_0 and the density parameter Omega*h^2 of the universe in the decaying neutrino theory for the ionisation of the interstellar medium (Sciama 1990 a, 1993). Using recent ... More
Optical Emission Lines from Warm Interstellar Clouds - a Decisive Test of the Decaying Neutrino TheoryJun 12 1998Recently developed instruments such as the Taurus Tunable Filter and WHAM should be able to detect some or all of the optical emission lines H$\alpha$, [OI] $\lambda$6300, [SII] $\lambda$6717, [NI] $\lambda$ 5200 and [NII] $\lambda$6584 from warm interstellar ... More
Deformation of quotients on a productMar 28 2011We consider the general problem of deforming a surjective map of modules $f : E \to F$ over a coproduct sheaf of rings $B=B_1 \otimes_A B_2$ when the domain module $E = B_1 \otimes_A E_2$ is obtained via extension of scalars from a $B_2$-module $E_2$. ... More
Double-logarithmic Scaling of the Structure Function F_2 at small xMay 29 1996Recent data on the structure function F_2(x,Q^2) at small values of x are analysed and compared with theoretical expectations. It is shown that the observed rise at small x is consistent with a logarithmic increase, growing logarithmically also with Q^2. ... More
Kondo screening and exhaustion in the periodic Anderson modelMar 01 2000We investigate the paramagnetic periodic Anderson model using the dynamical mean-field theory in combination with the modified perturbation theory which interpolates between the weak and strong coupling limits. For the symmetric PAM, the ground state ... More
Selected Parity Violation ExperimentsJan 22 2004I start by reviewing existing $\vec{p}p$ measurements with particular emphasis on the recent 221 MeV $\vec{p}p$ measurement at TRIUMF which permitted the weak meson-nucleon coupling constants $h^{pp}_\rho$ and $h^{pp}_\omega$ to be determined separately ... More
A Macroscopic Classical System with EntanglementJun 26 2014It is possible to construct a classical, macroscopic system which has a mathematical structure that is exactly the same as that of a quantum mechanical system and which can be put into a state which is identical to quantum mechanical entanglement. This ... More
Bond-Bending and Bond-Stretching Phonons in Ferromagnetic La_0.7Sr_0.3MnO_3Mar 23 2005Longitudinal optical phonons with oxygen character were measured in La_0.7Sr_0.3MnO_3 by inelastic neutron scattering in the (1 0 0) cubic direction and results were compared with shell model predictions. Measurements were performed in several Brillouin ... More
Chirality of wave functions for three coalescing levelsAug 10 2007The coalescence of three levels has particular attractive features. Even though it may be difficult to realise such event in the laboratory (three additional real parameters must be adjusted), to take up the challenge seems worthwhile. In the same way ... More
Phases of Wave Functions and Level RepulsionJan 11 1999Avoided level crossings are associated with exceptional points which are the singularities of the spectrum and eigenfunctions, when they are considered as functions of a coupling parameter. It is shown that the wave function of {\it one} state changes ... More
A Compendium of Hopf-Like Bifurcations in Piecewise-Smooth Dynamical SystemsApr 30 2018This Letter outlines 20 geometric mechanisms by which limit cycles are created locally in two-dimensional piecewise-smooth systems of ODEs. These include boundary equilibrium bifurcations of hybrid systems, Filippov systems, and continuous systems, and ... More
A general framework for boundary equilibrium bifurcations of Filippov systemsApr 30 2018As parameters are varied a boundary equilibrium bifurcation (BEB) occurs when an equilibrium collides with a discontinuity surface in a piecewise-smooth system of ODEs. Under certain genericity conditions, at a BEB the equilibrium either transitions to ... More
The Crepant Resolution Conjecture for 3-dimensional flags modulo an involutionAug 06 2007After fixing a non-degenerate bilinear form on a vector space V we define an involution of the manifold of flags F in V by taking a flag to its orthogonal complement. When V is of dimension 3 we check that the Crepant Resolution Conjecture of J. Bryan ... More
The noncommutative Lorentzian cylinder as an isospectral deformationOct 08 2003Oct 15 2003We present a new example of a finite-dimensional noncommutative manifold, namely the noncommutative cylinder. It is obtained by isospectral deformation of the canonical triple associated to the Euclidean cylinder. We discuss Connes' character formula ... More
A stable partitioned FSI algorithm for incompressible flow and elastic solidsAug 26 2013A stable partitioned algorithm for coupling incompressible flows with compressible elastic solids is described. This added-mass partitioned (AMP) scheme requires no sub-iterations, can be made fully second- or higher-order accurate, and remains stable ... More
On the Ionisation of Warm Opaque Interstellar Clouds and the Intercloud MediumFeb 21 1997In this paper we use a number of observations to construct an integrated picture of the ionisation in the interiors of quiescent warm opaque interstellar clouds and in the intercloud medium (ICM) outside dense HII regions and hot dilute bubbles. Our main ... More
Frustration of antiferromagnetism in the t-t'-Hubbard model at weak couplingFeb 22 1998Apr 14 1998The perfect-nesting instability towards antiferromagnetism of the Hubbard model is suppressed by next-nearest neighbor hopping t'. The exact asymptotic behavior of the critical coupling U_c(t') at small t' is calculated in dimensions d=2,3 and infinity ... More
CP Violation, Neutrino Mixing and the Baryon AsymmetryAug 26 2001Oct 05 2001We study neutrino masses and mixings based on the simplest SO(10) mass relations and the seesaw mechanism. We find that the requirement of large neutrino mixings determines the relative magnitude of the heavy Majorana neutrino masses in terms of the known ... More
Strange magnetic moment of the nucleon and SU(3) breaking: group theoretical approachApr 04 2005Aug 16 2005An extended group-theoretical approach to magnetic moments of the octet baryons is proposed with the aim of extracting the strange magnetic moment of the nucleon. Special attention is given to flavor SU(3) breaking. In this approach, isoscalar and isovector ... More
Quark-hadron duality and hadron properties from correlators of pseudoscalar and axial currentsFeb 23 2006We study the operator product expansion (OPE) and quark-hadron duality for 2- and 3-point correlators of the axial (A) and pseudoscalar (P) currents of the light quarks. In the chiral limit these correlators are often dominated by nonperturbative power ... More
Linearized supergravity from Matrix theoryDec 19 1997Mar 10 1998We show that the linearized supergravity potential between two objects arising from the exchange of quanta with zero longitudinal momentum is reproduced to all orders in 1/r by terms in the one-loop Matrix theory potential. The essential ingredient in ... More
Logarithmic FlatnessJan 11 2016A map of fine log schemes $X \to Y$ induces a map from the scheme underlying $X$ to Olsson's algebraic stack of strict morphisms of fine log schemes over $Y$. A sheaf on $X$ is called \emph{log flat over} $Y$ iff it is flat over this algebraic stack. ... More
The pion-cloud contribution to the electromagnetic nucleon structureOct 19 2015The present contribution continues and extends foregoing work on the calculation of electroweak form factors of hadrons using the point-form of relativistic quantum mechanics. Here we are particularly interested in studying pionic effects on the electromagnetic ... More
Strong-coupling scenario of a metamagnetic transitionJun 06 2001We investigate the periodic Anderson model in the presence of an external magnetic field, using dynamical mean-field theory in combination with the modified perturbation theory. A metamagnetic transition is observed which exhibits a massive change in ... More
Microscopic calculation of 240Pu scission with a finite-range effective forceOct 07 2009Oct 07 2009Hartree-Fock-Bogoliubov calculations of hot fission in $^{240}\textrm{Pu}$ have been performed with a newly-implemented code that uses the D1S finite-range effective interaction. The hot-scission line is identified in the quadrupole-octupole-moment coordinate ... More
The Classical Solutions of the Dimensionally Reduced Gravitational Chern-Simons TheoryJun 04 2003The Kaluza-Klein reduction of the 3d gravitational Chern-Simons term to a 2d theory is equivalent to a Poisson-sigma model with fourdimensional target space and degenerate Poisson tensor of rank 2. Thus two constants of motion (Casimir functions) exist, ... More
Global and Local Aspects of Exceptional PointNov 15 2002Exceptional points are singularities of eigenvalues and eigenvectors for complex values of, say, an interaction parameter. They occur universally and are square root branch point singularities of the eigenvalues in the vicinity of level repulsions. The ... More
The Maxwell equations including magnetic monopolesJan 28 2004Apr 10 2005The derivation of the Maxwell equations is reproduced whereby magnetic charges are included. This ansatz yields the results: 1) Longitudinal Ampere forces in a differential magnetostatic force law are improbable. Otherwise an electric current would generate ... More
Periodic derivations and prederivations of Lie algebrasAug 17 2011We consider finite-dimensional complex Lie algebras admitting a periodic derivation, i.e., a nonsingular derivation which has finite multiplicative order. We show that such Lie algebras are at most two-step nilpotent and give several characterizations, ... More
Two-qubit Projective Measurements are Universal for Quantum ComputationNov 23 2001Apr 09 2002Nielsen [quant-ph/0108020] showed that universal quantum computation is possible given quantum memory and the ability to perform projective measurements on up to 4-qubits. We describe an improved method that requires only 2-qubit measurements, which are ... More
Choi's Proof and Quantum Process TomographyJan 25 2002Quantum process tomography is a procedure by which an unknown quantum operation can be fully experimentally characterized. We reinterpret Choi's proof of the fact that any completely positive linear map has a Kraus representation [Lin. Alg. and App., ... More
Effective Action and Hawking Flux from Covariant Perturbation TheoryAug 26 2004The computation of the radiation flux related to the Hawking temperature of a Schwarzschild Black Hole or another geometric background is still well-known to be fraught with a number of delicate problems. In spherical reduction, as shown by one of the ... More
Characteristic classes in the Chow ringDec 10 1994We study the ring of characteristic classes with values in the Chow ring for principal $G$-bundles over schemes. If we consider bundles which are locally trivial in the Zariski topology, then we show, for $G$ reductive, that this ring is isomorphic to ... More
Detecting relic gravitational waves in the CMB: Optimal parameters and their constraintsFeb 11 2009Mar 27 2009The prospect of detecting relic gravitational waves (RGWs), through their imprint in the cosmic microwave background radiation, provides an excellent opportunity to study the very early Universe. In simplest viable theoretical models the RGW background ... More
An Integro-Differential Conservation Law arising in a Model of Granular FlowJan 11 2011We study a scalar integro-differential conservation law. The equation was first derived in [2] as the slow erosion limit of granular flow. Considering a set of more general erosion functions, we study the initial boundary value problem for which one can ... More
Scalar Quarkonium MassesAug 13 1996We evaluate the valence approximation to the mass of scalar quarkonium for a range of different parameters. Our results strongly suggest that the infinite volume continuum limit of the mass of $s\overline{s}$ scalar quarkonium lies well below the mass ... More
Continuum Limit of Scalar Masses and Mixing EnergiesNov 04 1998Dec 02 1998We evaluate the continuum limit of the valence approximation to the mass of scalar quarkonium and to the scalar quarkonium-glueball mixing energy for a range of different quark masses. Our results answer several questions raised by the proposed identification ... More
Improved Error Estimate for the Valence ApproximationApr 10 1998We construct a systematic mean-field-improved coupling constant and quark loop expansion for corrections to the valence (quenched) approximation to vacuum expectation values in the lattice formulation of QCD. Terms in the expansion are evaluated by a ... More
Coupling Constant and Quark Loop Expansion for Corrections to the Valence ApproximationNov 19 1998Feb 15 1999For full QCD vacuum expectation values we construct an expansion in quark loop count and in powers of a coupling constant. The leading term in this expansion is the valence (quenched) approximation vacuum expectation value. Higher terms give corrections ... More
Scalar Quarkonium Masses and Mixing with the Lightest Scalar GlueballMay 27 1998We evaluate the continuum limit of the valence (quenched) approximation to the mass of the lightest scalar quarkonium state, for a range of different quark masses, and to the mixing energy between these states and the lightest scalar glueball. Our results ... More
The microscopic theory of fissionOct 09 2009Fission-fragment properties have been calculated for thermal neutron-induced fission on a $^{239}\textrm{Pu}$ target, using constrained Hartree-Fock-Bogoliubov calculations with a finite-range effective interaction. A quantitative criterion based on the ... More
Absolute conservation law for black holesFeb 23 1999Nov 08 1999In all 2d theories of gravity a conservation law connects the (space-time dependent) mass aspect function at all times and all radii with an integral of the matter fields. It depends on an arbitrary constant which may be interpreted as determining the ... More
Phonon Mechanism of the Ferromagnetic Transition in La1-xSrxMnO3Dec 15 2003Temperature dependence of longitudinal optical phonons with oxygen character was measured in La1-xSrxMnO3 (x=0.2, 0.3) by inelastic neutron scattering in the (1 0 0) cubic direction. The zone center mode intensity is consistent with the Debye-Waller factor. ... More
A New Method for Cross Polarized Delay Calibration of Radio InterferometersMay 17 2012Radio interferometers can measure the full polarization state of incoming waves by cross--correlating all combinations of two orthogonal polarizations at each antenna. The independent sets of electronics used to detect the two polarization states will ... More
Coherence and Optical Emission from Bilayer Exciton CondensatesNov 16 2010Experiments aimed at demonstrating Bose-Einstein condensation of excitons in two types of experiments with bilayer structures (coupled quantum wells) are reviewed, with an emphasis on the basic effects. Bose-Einstein condensation implies the existence ... More
Gamma Rays from Near-Solar WIMP AnnihilationsMar 26 2001If weakly-interacting massive particles (WIMPs) make up the galactic dark matter halo, high densities of such particles would exist near massive bodies, such as the sun. The resulting annihilations are believed to produce neutrinos, gamma rays and other ... More
Repulsion of Resonance States and Exceptional PointsSep 15 1999Level repulsion is associated with exceptional points which are square root singularities of the energies as functions of a (complex) interaction parameter. This is also valid for resonance state energies. Using this concept it is argued that level anti-crossing ... More
Are Neutrino Oscillations Compatible with the Decaying Neutrino Theory for the Ionisation of Hydrogen in the Interstellar Medium?Nov 11 1998Recent Super-Kamiokande data have greatly strengthened the hypothesis that the atmospheric neutrino anomaly is mainly due to nearly maximal oscillations between $\nu_{\mu}$ and either $\nu_{\tau}$ or a sterile neutrino $\nu^s_{\mu}$.In this letter we ... More
A simple model of chromospheric evaporation and condensation driven conductively in a solar flareSep 05 2014Magnetic energy released in the corona by solar flares reaches the chromosphere where it drives characteristic upflows and downflows known as evaporation and condensation. These flows are studied here for the case where energy is transported to the chromosphere ... More
Regularization and supersymmetry-restoring counterterms in supersymmetric QCDMar 01 2001Mar 21 2001We calculate symmetry-restoring counterterms in supersymmetric QCD at the one-loop level. First we determine loop corrections to the supersymmetry and gauge transformations and find counterterms in such a way that the symmetry algebra holds at the one-loop ... More
The Wrong Kind of GravityMay 11 1999The KPZ formula shows that coupling central charge less than one spin models to 2D quantum gravity dresses the conformal weights to get new critical exponents, where the relation between the original and dressed weights depends only on the central charge. ... More
Quantized magnetic flux through the orbits of hydrogen-like atoms within the atomic model of SommerfeldFeb 25 2013Within the Sommerfeld atomic model the quantization of magnetic flux through the electronic orbits is investigated together with its dependency on additional sources of magnetic fields. These sources alter the magnetic flux through the atomic orbits and ... More
An Alternative to KaluzaNov 25 2008Dec 04 2008In Kaluza derived theories the electromagnetic potential is interpreted as a part of the metric in a higher dimensional theory of gravity. Here we present a more Yang-Mills like unification of classical electromagnetism and gravity within five dimensions, ... More
Characteristic classes and quadric bundlesDec 09 1994We construct Euler and Stiefel-Whitney classes of vector bundles with quadratic form by analyzing the intersection theory of the associated quadric bundles. We also compute the Chow rings of quadric and isotropic flag bundles. Along the way, we prove ... More
Scales and the fine structure of K(R). Part I: Acceptability above the realsMay 16 2006This article is Part I in a series of three papers devoted to determining the minimal complexity of scales in the inner model $K(\mathbb{R})$. Here, in Part I, we shall complete our development of a fine structure theory for $K(\mathbb{R})$ which is essential ... More
The instantaneous local transition of a stable equilibrium to a chaotic attractor in piecewise-smooth systems of differential equationsMay 31 2016An attractor of a piecewise-smooth continuous system of differential equations can bifurcate from a stable equilibrium to a more complicated invariant set when it collides with a switching manifold under parameter variation. Here numerical evidence is ... More
Charge storage in nanotubes: the case of a 2-1 electrolyteOct 03 2017We consider a 2-1 electrolyte in contact with a narrow nanotube, which only allows one-dimensional storage along the axis. The asymmetry does not allow an a priori definition of the potential of zero charge; instead, the natural reference is the electrode ... More
Scalar Quarkonium Masses and Mixing with the Lightest Scalar GlueballOct 04 1999We evaluate the continuum limit of the valence (quenched) approximation to the mass of the lightest scalar quarkonium state for a range of different quark masses and to the mixing energy between these states and the lightest scalar glueball. Our results ... More
A Dynamical Model for Nuclear Structure FunctionsJul 11 1995The dynamical origins of the EMC effect are studied. We conclude that a swelling in size of a bound nucleon as well as nuclear binding plays an important r\^ole in determining the parton distributions within a bound nucleon. We find that the distortion ... More
Bound States in Coulomb Systems - Old Problems and New SolutionsOct 10 2011We analyze the quantum statistical treatment of bound states in Hydrogen considered as a system of electrons and protons. Within this physical picture we calculate isotherms of pressure for Hydrogen in a broad density region and compare to some results ... More
On the quantum statistics of bound states within the Rutherford model of matterMar 08 2012The quantum statistical treatment of the Rutherford model, considering matter as a system of point charges (electrons and nuclei) is analyzed. First, in the historical context, the solutions of different fundamental problems, such as the divergence of ... More
SNR G349.7+0.2: A gamma-ray source in the far 3 kpc arm of the Galactic centerJan 14 2014Feb 07 2014We analyze the HI absorption profile for TeV Supernova Remnant (SNR) G349.7+0.2 based on updated knowledge of the inner Galaxy's structure. We significantly revise its kinematic distance from the previous ~ 22 kpc to ~11.5 kpc, indicating it is in the ... More
Nuclear Scission and Quantum LocalizationMar 17 2011We examine nuclear scission within a fully quantum-mechanical microscopic framework, focusing on the non-local aspects of the theory. Using $^{240}\textrm{Pu}$ hot fission as an example, we discuss the identification of the fragments and the calculation ... More
Experimentally Derived Dielectronic Recombination Rate Coefficients for Heliumlike C V and Hydrogenic O VIIIApr 20 1999Using published measurements of dielectronic recombination (DR) resonance strengths and energies for C V to C IV and O VIII to O VII, we have calculated the DR rate coefficient for these ions. Our derived rates are in good agreement with multiconfiguration, ... More
A new method to measure the attenuation of hadrons in extensive air showersJul 09 2009Extensive air showers are generated through interactions of high-energy cosmic rays impinging the Earth's atmosphere. A new method is described to infer the attenuation of hadrons in air showers. The numbers of electrons and muons, registered with the ... More
Exceptional Points of Non-hermitian OperatorsApr 24 2003Exceptional points associated with non-hermitian operators, i.e. operators being non-hermitian for real parameter values, are investigated. The specific characteristics of the eigenfunctions at the exceptional point are worked out. Within the domain of ... More
The physics of exceptional pointsOct 25 2012A short resume is given about the nature of exceptional points (EPs) followed by discussions about their ubiquitous occurrence in a great variety of physical problems. EPs feature in classical as well as in quantum mechanical problems. They are associated ... More
Sample size effects in multivariate fitting of correlated dataAug 15 2008Aug 24 2008A common problem in analysis of experiments or in lattice QCD simulations is fitting a parameterized model to the average over a number of samples of correlated data values. If the number of samples is not infinite, estimates of the variance of the parameters ... More
Electron Spin Precession at CEBAFJan 28 2009The nuclear physics experiments at the Thomas Jefferson National Accelerator Facility often require longitudinally polarized electrons to be simultaneously delivered to three experimental halls. The degree of longitudinal polarization to each hall varies ... More
On the Interaction Between Cosmic Rays and Dark Matter Molecular Clouds in the Milky Way. l Basic ConsiderationsJun 09 1999We explore some basic observational consequences of assuming that the dark matter in the Milky Way consists mainly of molecular clouds, and that cosmic rays can penetrate these clouds. In a favoured model of the clouds, this penetration would have the ... More