Results for "Peter Bubenik"

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Context for models of concurrencyAug 29 2006Many categories have been used to model concurrency. Using any of these, the challenge is to reduce a given model to a smaller representation which nevertheless preserves the relevant computer-scientific information. That is, one wants to replace a given ... More
A model category for local po-spacesJun 17 2005Jan 10 2006Locally partial-ordered spaces (local po-spaces) have been used to model concurrent systems. We provide equivalences for these spaces by constructing a model category containing the category of local po-spaces. We show the category of simplicial presheaves ... More
Cell attachments and the homology of loop spaces and differential graded algebrasJan 17 2006The cell-attachment problem, perhaps first studied by J.H.C. Whitehead around 1940, asks one to describe the effect of attaching one or more cells, on the algebraic invariants of a topological space. This thesis studies the effect of cell attachments ... More
Free and semi-inert cell attachmentsDec 19 2003Let $Y$ be the space obtained by attaching a finite-type wedge of cells to a simply-connected, finite-type CW-complex. We introduce the free and semi-inert conditions on the attaching map which broadly generalize the previously studied inert condition. ... More
Models and van Kampen theorems for directed homotopy theoryOct 22 2008We study topological spaces with a distinguished set of paths, called directed paths. Since these directed paths are generally not reversible, the directed homotopy classes of directed paths do not assemble into a groupoid, and there is no direct analog ... More
Simplicial models for concurrencyNov 30 2010Mar 29 2011We model both concurrent programs and the possible executions from one state to another in a concurrent program using simplices. The latter are calculated using necklaces of simplices in the former.
Separated Lie models and the homotopy Lie algebraJun 21 2004May 07 2007A simply connected topological space X has homotopy Lie algebra $\pi_*(\Omega X) \tensor \Q$. Following Quillen, there is a connected differential graded free Lie algebra (dgL) called a Lie model, which determines the rational homotopy type of X, and ... More
The persistence landscape and some of its propertiesOct 11 2018Jan 26 2019Persistence landscapes map persistence diagrams into a function space, which may often be taken to be a Banach space or even a Hilbert space. In the latter case, it is a feature map and there is an associated kernel. The main advantage of this summary ... More
Statistical topological data analysis using persistence landscapesJul 27 2012Jan 23 2015We define a new topological summary for data that we call the persistence landscape. Since this summary lies in a vector space, it is easy to combine with tools from statistics and machine learning, in contrast to the standard topological summaries. Viewed ... More
Embeddings of Persistence Diagrams into Hilbert SpacesMay 11 2019Since persistence diagrams do not admit an inner product structure, a map into a Hilbert space is needed in order to use kernel methods. It is natural to ask if such maps necessarily distort the metric on persistence diagrams. We show that persistence ... More
A persistence landscapes toolbox for topological statisticsDec 31 2014Aug 28 2015Topological data analysis provides a multiscale description of the geometry and topology of quantitative data. The persistence landscape is a topological summary that can be easily combined with tools from statistics and machine learning. We give efficient ... More
Homological Algebra for Persistence ModulesMay 14 2019We develop some aspects of the homological algebra of persistence modules, in both the one-parameter and multi-parameter settings, considered as either sheaves or graded modules. The two theories are different. We consider the graded module and sheaf ... More
Topological spaces of persistence modules and their propertiesFeb 22 2018Oct 25 2018Persistence modules are a central algebraic object arising in topological data analysis. The notion of interleaving provides a natural way to measure distances between persistence modules. We consider various classes of persistence modules, including ... More
Stabilizing the output of persistent homology computationsDec 05 2015We propose a general technique for extracting a larger set of stable information from persistent homology computations than is currently done. The persistent homology algorithm is generally seen as a procedure which starts with a filtered complex and ... More
Densities for random balanced samplingAug 29 2006A random balanced sample (RBS) is a multivariate distribution with n components X_1,...,X_n, each uniformly distributed on [-1, 1], such that the sum of these components is precisely 0. The corresponding vectors X lie in an (n-1)-dimensional polytope ... More
Embeddings of Persistence Diagrams into Hilbert SpacesMay 11 2019May 27 2019Since persistence diagrams do not admit an inner product structure, a map into a Hilbert space is needed in order to use kernel methods. It is natural to ask if such maps necessarily distort the metric on persistence diagrams. We show that persistence ... More
A statistical approach to persistent homologyJul 25 2006Aug 01 2007Assume that a finite set of points is randomly sampled from a subspace of a metric space. Recent advances in computational topology have provided several approaches to recovering the geometric and topological properties of the underlying space. In this ... More
Graph products of spheres, associative graded algebras and Hilbert seriesJan 28 2009Mar 08 2010Given a finite, simple, vertex-weighted graph, we construct a graded associative (non-commutative) algebra, whose generators correspond to vertices and whose ideal of relations has generators that are graded commutators corresponding to edges. We show ... More
Categorification of persistent homologyMay 16 2012Jan 08 2014We redevelop persistent homology (topological persistence) from a categorical point of view. The main objects of study are diagrams, indexed by the poset of real numbers, in some target category. The set of such diagrams has an interleaving distance, ... More
Wasserstein distance for generalized persistence modules and abelian categoriesSep 25 2018In persistence theory and practice, measuring distances between modules is central. The Wasserstein distances are the standard family of L^p distances for persistence modules. They are defined in a combinatorial way for discrete invariants called persistence ... More
Graded persistence diagrams and persistence landscapesApr 29 2019We introduce a refinement of the persistence diagram, the graded persistence diagram. It is a sequence of diagrams whose sum is the persistence diagram. The points in the k-th graded persistence diagram are signed and are the local maxima and minima, ... More
Stabilizing the unstable output of persistent homology computationsDec 05 2015Oct 25 2018We propose a general technique for extracting a larger set of stable information from persistent homology computations than is currently done. The persistent homology algorithm is usually viewed as a procedure which starts with a filtered complex and ... More
Metrics for generalized persistence modulesDec 13 2013Feb 05 2015We consider the question of defining interleaving metrics on generalized persistence modules over arbitrary preordered sets. Our constructions are functorial, which implies a form of stability for these metrics. We describe a large class of examples, ... More
Min-type Morse theory for configuration spaces of hard spheresAug 15 2011Aug 29 2011We study configuration spaces of hard spheres in a bounded region. We develop a general Morse-theoretic framework, and show that mechanically balanced configurations play the role of critical points. As an application, we find the precise threshold radius ... More
Higher interpolation and extension for persistence modulesMar 24 2016The use of topological persistence in contemporary data analysis has provided considerable impetus for investigations into the geometric and functional-analytic structure of the space of persistence modules. In this paper, we isolate a coherence criterion ... More
Interleaving and Gromov-Hausdorff distanceJul 19 2017Apr 26 2018One of the central notions to emerge from the study of persistent homology is that of interleaving distance. It has found recent applications in symplectic and contact geometry, sheaf theory, computational geometry, and phylogenetics. Here we present ... More
Higher interpolation and extension for persistence modulesMar 24 2016Mar 20 2017The use of topological persistence in contemporary data analysis has provided considerable impetus for investigations into the geometric and functional-analytic structure of the space of persistence modules. In this paper, we isolate a coherence criterion ... More
Statistical topology via Morse theory, persistence and nonparametric estimationAug 25 2009Mar 04 2010In this paper we examine the use of topological methods for multivariate statistics. Using persistent homology from computational algebraic topology, a random sample is used to construct estimators of persistent homology. This estimation procedure can ... More
Closed Model Categories for Presheaves of Simplicial Groupoids and Presheaves of 2-GroupoidsJan 06 2003Feb 05 2009It is shown that the category of presheaves of simplicial groupoids and the category of presheaves of 2-groupoids have Quillen closed model structures. Furthermore, their homotopy categories are equivalent to the homotopy categories of simplicial presheaves ... More
Persistent homology detects curvatureMay 30 2019Persistent homology computations are completely characterized by a set of intervals called a bar code. It is often said that the long intervals represent the "topological signal" and the short intervals represent "noise". We give evidence to dispute this ... More
Using persistent homology and dynamical distances to analyze protein bindingDec 03 2014Jul 30 2015Persistent homology captures the evolution of topological features of a model as a parameter changes. The most commonly used summary statistics of persistent homology are the barcode and the persistence diagram. Another summary statistic, the persistence ... More
Persistent homology detects curvatureMay 30 2019Jun 12 2019In topological data analysis, persistent homology is used to study the "shape of data". Persistent homology computations are completely characterized by a set of intervals called a bar code. It is often said that the long intervals represent the "topological ... More
A spatial model for selection and cooperationMar 02 2016Oct 11 2016We study the evolution of cooperation in an interacting particle system with two types. The model we investigate is an extension of a two-type biased voter model. One type (called defector) has a (positive) bias $\alpha$ with respect to the other type ... More
Spectral asymptotics of the Laplacian on supercritical bond-percolation graphsJun 21 2005Jul 03 2007We investigate Laplacians on supercritical bond-percolation graphs with different boundary conditions at cluster borders. The integrated density of states of the Dirichlet Laplacian is found to exhibit a Lifshits tail at the lower spectral edge, while ... More
Regret and Jeffreys Integrals in Exp. FamiliesMar 31 2009The problem of whether minimax redundancy, minimax regret and Jeffreys integrals are finite or infinite are discussed.
General Solutions for Multispin Two-Time Correlation and Response Functions in the Glauber-Ising ChainJul 09 2003The kinetic Glauber-Ising spin chain is one of the very few exactly solvable models of non-equilibrium statistical mechanics. Nevertheless, existing solutions do not yield tractable expressions for two-time correlation and response functions of observables ... More
Changing gears: Isospectrality via eigenderivative transplantationSep 11 2015We introduce a new method for constructing isospectral quantum graphs that is based on transplanting derivatives of eigenfunctions. We also present simple digraphs with the same reversing zeta function, which generalizes the Bartholdi zeta function to ... More
A spatial model for selection and cooperationMar 02 2016Nov 02 2016We study the evolution of cooperation in an interacting particle system with two types. The model we investigate is an extension of a two-type biased voter model. One type (called defector) has a (positive) bias $\alpha$ with respect to the other type ... More
Statistical Cosmology with Quadratic Density FieldsAug 15 2002Primordial fluctuations in the cosmic density are usually assumed to take the form of a Gaussian random field that evolves under the action of gravitational instability. In the early stages, while they have low amplitude, the fluctuations grow linearly. ... More
Open system trajectories specify fluctuating work but not heatMay 24 2016Aug 26 2016Based on the explicit knowledge of a Hamiltonian of mean force, the classical statistical mechanics and equilibrium thermodynamics of open systems in contact with a thermal environment at arbitrary interaction strength can be formulated. Even though the ... More
Aging in One-Dimensional Coagulation-Diffusion Processes and the Fredrickson-Andersen ModelFeb 26 2007We analyse the aging dynamics of the one-dimensional Fredrickson-Andersen (FA) model in the nonequilibrium regime following a low temperature quench. Relaxation then effectively proceeds via diffusion limited pair coagulation (DLPC) of mobility excitations. ... More
Observable Dependent Quasi-Equilibrium in Slow DynamicsMay 31 2004Apr 18 2005We present examples demonstrating that quasi-equilibrium fluctuation-dissipation behavior at short time differences is not a generic feature of systems with slow non-equilibrium dynamics. We analyze in detail the non-equilibrium fluctuation-dissipation ... More
Identifiability of Gaussian structural equation models with equal error variancesMay 11 2012Aug 28 2013We consider structural equation models in which variables can be written as a function of their parents and noise terms, which are assumed to be jointly independent. Corresponding to each structural equation model, there is a directed acyclic graph describing ... More
Some limit results for Markov chains indexed by treesJun 14 2014We consider a sequence of Markov chains $(\mathcal X^n)_{n=1,2,...}$ with $\mathcal X^n = (X^n_\sigma)_{\sigma\in\mathcal T}$, indexed by the full binary tree $\mathcal T = \mathcal T_0 \cup \mathcal T_1 \cup ...$, where $\mathcal T_k$ is the $k$th generation ... More
Percolation HamiltoniansFeb 26 2010Jan 09 2011There has been quite some activity and progress concerning spectral asymptotics of random operators that are defined on percolation subgraphs of different types of graphs. In this short survey we record some of these results and explain the necessary ... More
Proceedings of the Twenty-Sixth Conference on Uncertainty in Artificial Intelligence (2010)May 11 2012Aug 28 2014This is the Proceedings of the Twenty-Sixth Conference on Uncertainty in Artificial Intelligence, which was held on Catalina Island, CA, July 8 - 11 2010.
Aspects of workDec 08 2015Various approaches of defining and determining work performed on a quantum system are compared. Any operational definition of work, however, must allow for two facts, first, that work characterizes a process rather than an instantaneous state of a system, ... More
A spatial model for selection and cooperationMar 02 2016We study the evolution of cooperation in an interacting particle system with two types. The model we investigate is an extension of a two-type biased voter model. One type (called defector) has a (positive) bias $\alpha$ with respect to the other type ... More
The Tasaki-Crooks quantum fluctuation theoremMay 09 2007Starting out from the recently established quantum correlation function expression of the characteristic function for the work performed by a force protocol on the system [cond-mat/0703213] the quantum version of the Crooks fluctuation theorem is shown ... More
Studying Attractor Symmetries by Means of Cross Correlation SumsMay 02 1996We use the cross correlation sum introduced recently by H. Kantz to study symmetry properties of chaotic attractors. In particular, we apply it to a system of six coupled nonlinear oscillators which was shown by Kroon et al. to have attractors with several ... More
Model Checking for a Class of Weighted AutomataApr 15 2003A large number of different model checking approaches has been proposed during the last decade. The different approaches are applicable to different model types including untimed, timed, probabilistic and stochastic models. This paper presents a new framework ... More
A note on the restricted universal enveloping algebra of a restricted Lie-Rinehart AlgebraMay 11 2015Lie-Rinehart algebras, also known as Lie algebroids, give rise to Hopf algebroids by a universal enveloping algebra construction, much as the universal enveloping algebra of an ordinary Lie algebra gives a Hopf algebra, of infinite dimension. In finite ... More
Some notes on biasedness and unbiasedness of two-sample Kolmogorov-Smirnov testJun 28 2011This paper deals with two-sample Kolmogorov-Smirnov test and its biasedness. This test is not unbiased in general in case of different sample sizes. We found out most biased distribution for some values of significance level $\alpha$. Moreover we discovered ... More
Symplectic homology of some Brieskorn manifoldsFeb 16 2015Feb 17 2016This paper consists of two parts. In the first part, we use symplectic homology to distinguish the contact structures on the Brieskorn manifolds $\Sigma(2l,2,2,2)$, which contact homology cannot distinguish. This answers a question from [22]. In the second ... More
Zeta-equivalent digraphs: Simultaneous cospectralityDec 15 2014May 14 2015We introduce a zeta function of digraphs that determines, and is determined by, the spectra of all linear combinations of the adjacency matrix, its transpose, the out-degree matrix, and the in-degree matrix. In particular, zeta-equivalence of graphs encompasses ... More
A finite alternation result for reversible boolean circuitsApr 09 2016We say that a reversible boolean function on n bits has alternation depth d if it can be written as the sequential composition of d reversible boolean functions, each of which acts only on the top n-1 bits or on the bottom n-1 bits. We show that every ... More
The quantum state-dependent gauge fields of JacobiApr 18 2016May 25 2016It is commonly understood that the Yang-Mills non-Abelian gauge fields is the natural generalization of the well known Abelian gauge group symmetry $U(1)$ in the electrodynamics. Taking into account that the problems of the localization and divergences ... More
The macroeconomic effect of the information and communication technology in HungaryApr 06 2012It was not until the beginning of the 1990s that the effects of information and communication technology on economic growth as well as on the profitability of enterprises raised the interest of researchers. After giving a general description on the relationship ... More
Mathematical Analysis of Money in the Scope of AusterityMay 23 2013Jun 10 2013This summarizes the study of the financial and economic crisis in Europe. The starting questions were: 1) Why do we have a crisis? Unde venis? 2) What will be the outcome? Quo vadis? Here is the reasoning which touches many areas, ranging from financial ... More
A sharp upper bound for the independence numberJul 30 2010Aug 18 2013An $r$-graph $G$ is a pair $(V,E)$ such that $V$ is a set and $E$ is a family of $r$-element subsets of $V$. The \emph{independence number} $\alpha(G)$ of $G$ is the size of a largest subset $I$ of $V$ such that no member of $E$ is a subset of $I$. The ... More
The maximum product of weights of cross-intersecting familiesDec 30 2015Two families $\mathcal{A}$ and $\mathcal{B}$ of sets are said to be cross-$t$-intersecting if each set in $\mathcal{A}$ intersects each set in $\mathcal{B}$ in at least $t$ elements. An active problem in extremal set theory is to determine the maximum ... More
Topology of Platonic Spherical Manifolds: From Homotopy to Harmonic AnalysisApr 05 2015We carry out the harmonic analysis on four Platonic spherical three-manifolds with different topologies. Starting out from the homotopies (Everitt 2004), we convert them into deck operations, acting on the simply connected three-sphere as the cover, and ... More
Hot Scalar Theory in Large N: Bose-Einstein CondensationOct 18 2000I review the Bose-Einstein condensation phase transition of dilute gases of cold atoms, for particle theorists acquainted with methods of field theory at finite temperature. I then discuss how the dependence of the phase transition temperature on the ... More
Phase Transition Temperatures at Next-to-Leading OrderApr 23 1992Broken gauge symmetries are typically restored at high temperature, and the leading-order result for the critical temperature $T_c$ was found many years ago by Weinberg and by Dolan and Jackiw. I find a simple expression for the next-to-leading order ... More
Gluon Bremsstrahlung in Weakly-Coupled PlasmasJul 06 2009Sep 10 2009I report on some theoretical progress concerning the calculation of gluon bremsstrahlung for very high energy particles crossing a weakly-coupled quark-gluon plasma. (i) I advertise that two of the several formalisms used to study this problem, the BDMPS-Zakharov ... More
Hot or dense matterOct 16 2000I review some properties of hot and/or dense releativistic matter. This review is aimed at a general audience of particle physicists.
An effective theory for omega << k << gT color dynamics in hot non-Abelian plasmasDec 10 1999A proper sequence of effective theories, corresponding to larger and larger distance scales, is crucial for analyzing real-time equilibrium physics in hot non-Abelian plasmas. For the study of color dynamics (by which I mean physics involving long wavelength ... More
Rates for non-perturbative processes in hot non-abelian plasmaOct 01 1998[Talk given at "Continuous Advances in QCD '98."] I give a simple physical picture of why the rate $\Gamma$ per unit volume of non-perturbative processes in hot non-Abelian plasmas (such as electroweak baryon number violation in the very early universe) ... More
B Violation in the Hot Standard ModelJun 09 1997I explain, as simply and pedagogically as I can, recent arguments that the high-temperature baryon number violation rate depends on the electroweak coupling as $\Gamma = # \alpha_\w^5 T^4$ (up to higher order corrections). This is in contrast to the form ... More
Numerical Analysis of the Anderson LocalizationSep 22 2006The aim of this paper is to demonstrate, by simple numerical simulations, the main transport properties of disordered electron systems.
Dimension dependence of the conductance distribution in the non-metallic regimesSep 17 2000Jan 18 2002We study numerically the form of the conductance distribution in the non-metallic regime for (1) weakly disordered systems which become insulating due to increase of the system length and (2) cubic d-dimensional systems, in which localization occours ... More
Hyperbolic automorphisms of free groupsJun 02 1999Sep 28 1999We prove that an automorphism $\phi:F\to F$ of a finitely generated free group $F$ is hyperbolic in the sense of Gromov if it has no nontrivial periodic conjugacy classes.
An Implementation of the Bestvina-Handel Algorithm for Surface HomeomorphismsMay 25 1999May 26 1999Bestvina and Handel have found an effective algorithm that determines whether a given homeomorphism of an orientable, possibly punctured surface is pseudo-Anosov. We present a software package in Java that realizes this algorithm for surfaces with one ... More
Homology groups of filtrationsJan 11 2011Apr 28 2011Such modern applications of topology as data analysis and digital image analysis have to deal with noise and other uncertainty. In this environment, topological spaces often appear equipped with a real valued function. Persistence is a measure of robustness ... More
On the Time Dependent Gross Pitaevskii- and Hartree EquationAug 08 2008We are interested in solutions $\Psi_t$ of the Schr\"odinger equation of $N$ interacting bosons under the influence of a time dependent external field, where the range and the coupling constant of the interaction scale with $N$ in such a way, that the ... More
Navier-Stokes equations and fluid turbulenceMar 27 2000An Eulerian-Lagrangian approach to incompressible fluids that is convenient for both analysis and physics is presented. Bounds on burning rates in combustion and heat transfer in convection are discussed, as well as results concerning spectra.
An almost trivial proof of the 4-colour theoremAug 27 2004Jun 25 2013Proving for triangulations an extended (sharper) version of the 4-colour theorem by induction, we manage to exclude the case which led to the failure of Kempe's attempted proof. The new idea is to claim the existence of a "nice" 4-colouring, in which ... More
alpha-nucleus potentials for the neutron-deficient p nucleiJan 31 2000alpha-nucleus potentials are one important ingredient for the understanding of the nucleosynthesis of heavy neutron-deficient p nuclei in the astrophysical gamma-process where these p nuclei are produced by a series of (gamma,n), (gamma,p), and (gamma,alpha) ... More
Simulations of R-parity Violating SUSY ModelsJan 10 2001In recent years there has been a great deal of interest in R-parity violating supersymmetric models. We explain the motivation for studying these models and explore the various phenomenological consequences of R-parity violation. It has become essential ... More
Gamma Ray BurstsApr 09 2012Apr 12 2012Gamma-ray bursts have been detected at photon energies up to tens of GeV. We review some recent developments in the X-ray to GeV photon phenomenology in the light of Swift and Fermi observations, and some of the theoretical models developed to explain ... More
Statistical Properties of Cosmological FluctuationsSep 27 2002In this pedagogical lecture, I introduce some of the basic terminology and description of fluctuating fields as they occur on cosmology. I define various statistical, cosmological and sample homogeneity and explain what is meant by the fair sample hypothesis ... More
On the class of chiral symmetry representations with scalar and pseudoscalar fieldsMay 12 2008In the following few pages an account is given of a theme, which I began in 1966 and followed to the present.
Bernoulli crossed products without almost periodic weightsAug 29 2015We prove a classification result for a large class of noncommutative Bernoulli crossed products $(P,\phi)^\Lambda \rtimes \Lambda$ without almost periodic states. Our results improve the classification results from [1], where only Bernoulli crossed products ... More
On the spectrum, no ghost theorem and modular invariance of $W_3$ stringsDec 02 1992A spectrum generating algebra is constructed and used to find all the physical states of the $W_3$ string with standard ghost number. These states are shown to have positive norm and their partition function is found to involve the Ising model characters ... More
Generalised BPS conditionsAug 16 2012We write down two E11 invariant conditions which at low levels reproduce the known half BPS conditions for type II theories. These new conditions contain, in addition to the familiar central charges, an infinite number of further charges which are required ... More
Running mass of the rho0 meson's implication for the dilepton mass spectrum and the mu+mu-/e+e- branching ratio in the K+ --> pi+l+l- decaysMar 01 1999We make an attempt to resolve the discrepancy of the observed e+e- mass spectrum in the K+ --> pi+e+e- decay with that predicted by meson dominance. To this end we investigate the properties of the rho0 propagator. We use dispersion relations to evaluate ... More
A Robust Mathematical Model for Clauser-Horne Experiments, With Implications for Rigorous Statistical AnalysisDec 10 2013Mar 27 2015Recent experiments have reached detection efficiencies sufficient to close the detection loophole, testing the Clauser-Horne (CH) version of Bell's inequality. For a similar future experiment to be completely loophole-free, it will be important to have ... More
A Rigorous Analysis of the Clauser-Horne-Shimony-Holt Inequality Experiment When Trials Need Not Be IndependentNov 14 2013May 19 2014The Clauser-Horne-Shimony-Holt (CHSH) inequality is a constraint that local theories must obey. Quantum Mechanics predicts a violation of this inequality in certain experimental settings. Treatments of this subject frequently make simplifying assumptions ... More
Marginal likelihood for parallel seriesOct 22 2008Suppose that $k$ series, all having the same autocorrelation function, are observed in parallel at $n$ points in time or space. From a single series of moderate length, the autocorrelation parameter $\beta$ can be estimated with limited accuracy, so we ... More
Search for the Higgs boson in the gamma gamma final state at the TevatronSep 04 2010We present searches for Higgs bosons decaying to the di-photon final state using up to 5.4/fb of data at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. Whilst the branching ratio to the di-photon final state is small in the Standard ... More
QCD for Collider PhysicsApr 14 2011May 09 2012These lectures are directed at a level suitable for graduate students in experimental and theoretical High Energy Physics. They are intended to give an introduction to the theory and phenomenology of quantum chromodynamics (QCD) as it is used in collider ... More
Imfit: A Fast, Flexible New Program for Astronomical Image FittingAug 05 2014Dec 03 2014I describe a new, open-source astronomical image-fitting program called Imfit, specialized for galaxies but potentially useful for other sources, which is fast, flexible, and highly extensible. A key characteristic of the program is an object-oriented ... More
How Large Are the Bars in Barred Galaxies?Aug 26 2005I present a study of the sizes (semimajor axes) of bars in disc galaxies, combining a detailed study of 65 S0-Sb galaxies with measurements of 70 Sb-Sd galaxies from Martin (1995). As has been noted before with smaller samples, bars in early-type (S0-Sb) ... More
Lyapunov exponent for inertial particles in the 2D Kraichnan model as a problem of Anderson localization with complex valued potentialNov 14 2005We exploit the analogy between dynamics of inertial particle pair separation in a random-in-time flow and the Anderson model of a quantum particle on the line in a spatially random real-valued potential. Thereby we get an exact formula for the Lyapunov ... More
Background Fluctuations in Heavy Ion Jet ReconstructionDec 10 2010Jan 03 2011We present a new study by the STAR Collaboration of background fluctuations in jet reconstruction in heavy ion collisions.
A mixed method for elasticity with the curl of displacements as a drilling degree of freedomOct 16 2012We present a mixed method for the linearized elasticity equations with independent approximation of the curl of the displacements. The curl can be seen as a drilling degree of freedom allowing for coupling with rotating objects and the direct application ... More
Observation of SCS decay $D^{+,0}\toωπ$ and branching fraction measurement of $D^0\to K_S^0K^+K^-$Jun 23 2015Jun 26 2015Using a data set of 2.92 $fb^{-1}$ of $e^+e^-$ collisions at the $\Psi$(3770) mass accumulated with the BESIII experiment we present preliminary results from our study of the singly Cabibbo-suppressed decays $D\to\omega\pi$ and the decay of $D^0\to K_S^0K^+K^-$. ... More
Extended Josephson Relation and Abrikosov lattice deformationDec 20 2011Feb 15 2012From the point of view of time-dependent Ginzburg Landau (TDGL) theory, a Josephson-like relation is derived for an Abrikosov vortex lattice accelerated and deformed by applied fields. Beginning with a review of the Josephson Relation derived from the ... More
Velocity Fields of Disk GalaxiesApr 27 2002Two dimensional velocity fields have been an important tool for nearly 30 years and are instrumental in understanding galactic mass distributions and deviations from an ideal galactic disk. Recently a number of new instruments have started to produce ... More
From Dual Models to String TheoryFeb 22 2008A personal view is given of the development of string theory out of dual models, including the analysis of the structure of the physical states and the proof of the No-Ghost Theorem, the quantization of the relativistic string, and the calculation of ... More