Results for "Harri Niemi"

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Influence of temperature dependent shear viscosity on elliptic flow at back- and forward rapidities in ultrarelativistic heavy-ion collisionsJul 30 2014Nov 12 2014We explore the influence of a temperature-dependent shear viscosity over entropy density ratio $\eta/s$ on the azimuthal anisotropies v_2 and v_4 of hadrons at various rapidities. We find that in Au+Au collisions at full RHIC energy, $\sqrt{s_{NN}}=200$ ... More
Zeroing in on the initial state -- tomography using bulk, jets and photonsJul 30 2014One of the unsolved problems in the current 'standard model' of heavy ion physics is the apparent rapid thermalization of QCD matter in the pre-equilibrium stage. While it is challenging to probe this mechanism directly, there are now several observables ... More
Jet quenching as a probe of the initial stages in heavy-ion collisionsFeb 08 2019Jet quenching provides a very flexible variety of observables which are sensitive to different energy- and time-scales of the strongly interacting matter created in heavy-ion collisions. Exploiting this versatility would make jet quenching an excellent ... More
Constraints from $v_2$ fluctuations for the initial state geometry of heavy-ion collisionsJan 09 2014The ability to accurately compute the series of coefficients $v_n$ characterizing the momentum space anisotropies of particle production in ultrarelativistic heavy ion collisions as a function of centrality is widely regarded as a triumph of fluid dynamics ... More
Elliptic flow from event-by-event hydrodynamicsJun 22 2011We present an event-by-event hydrodynamical framework which takes into account the initial density fluctuations arising from a Monte Carlo Glauber model. The elliptic flow is calculated with the event plane method and a one-to-one comparison with the ... More
Closing the equations of motion of anisotropic fluid dynamics by a judicious choice of moment of the Boltzmann equationJun 29 2016In Moln\'ar et al. [Phys. Rev. D 93, 114025 (2016)] the equations of anisotropic dissipative fluid dynamics were obtained from the moments of the Boltzmann equation based on an expansion around an arbitrary anisotropic single-particle distribution function. ... More
Closing the equations of motion of anisotropic fluid dynamics by a judicious choice of moment of the Boltzmann equationJun 29 2016Dec 02 2016In Moln\'ar et al. [Phys. Rev. D 93, 114025 (2016)] the equations of anisotropic dissipative fluid dynamics were obtained from the moments of the Boltzmann equation based on an expansion around an arbitrary anisotropic single-particle distribution function. ... More
Elliptic flow from event-by-event hydrodynamics with fluctuating initial stateDec 01 2010We develop an event-by-event ideal hydrodynamical framework where initial state density fluctuations are present and where we use a similar flow-analysis method as in the experiments to make a one-to-one $v_2$ comparison with the measured data. Our studies ... More
Event-by-event hydrodynamics and elliptic flow from fluctuating initial stateJul 02 2010Jan 26 2011We develop a framework for event-by-event ideal hydrodynamics to study the differential elliptic flow which is measured at different centralities in Au+Au collisions at Relativistic Heavy Ion Collider (RHIC). Fluctuating initial energy density profiles, ... More
Benchmark Computations of stresses in a spherical dome with shell finite elementsJul 14 2015We present a computational framework for analysing thin shell structures using the finite element method. The framework is based on a mesh-dependent shell model which we derive from the general laws of three-dimensional elasticity. We apply the framework ... More
Examination of directed flow as a signature of the softest point of the equation of state in QCD matterJan 28 2016Sep 26 2016We analyze the directed flow of protons and pions in high-energy heavy-ion collisions in the incident energy range from $\sqrt{s_{{\scriptscriptstyle NN}}}=7.7$ to 27 GeV within a microscopic transport model. Standard hadronic transport approaches do ... More
A fully Bayesian strategy for high-dimensional hierarchical modeling using massively parallel computingJun 21 2016Markov chain Monte Carlo (MCMC) is the predominant tool used in Bayesian parameter estimation for hierarchical models. When the model expands due to an increasing number of hierarchical levels, number of groups at a particular level, or number of observations ... More
Resistive dissipative magnetohydrodynamics from the Boltzmann-Vlasov equationFeb 05 2019We derive the equations of motion of relativistic, resistive, second-order dissipative magnetohydrodynamics from the Boltzmann-Vlasov equation using the method of moments. We thus extend our previous work [Phys. Rev. D 98, 076009 (2018)], where we only ... More
Equation of state dependence of directed flow in a microscopic transport modelNov 23 2016We study the sensitivities of the directed flow in Au+Au collisions on the equation of state (EoS), employing the transport theoretical model JAM. The EoS is modified by introducing a new collision term in order to control the pressure of a system by ... More
On the Infrared Limit of Two Dimensional QCDNov 18 1993Dec 02 1993We study the infrared limit of two dimensional QCD, with massless dynamical Dirac fermions that are in the fundamental representation of the gauge group. We find that the theory reduces to a spin generalization of the Calogero model with an additional ... More
How large is the Knudsen number reached in fluid dynamical simulations of ultrarelativistic heavy ion collisions?Apr 29 2014We investigate the applicability of fluid dynamics in ultrarelativistic heavy ion (AA) collisions and high multiplicity proton nucleus (pA) collisions. In order for fluid dynamics to be applicable the microscopic and macroscopic distance/time scales of ... More
Influence of the shear viscosity of the quark-gluon plasma on elliptic flow in ultrarelativistic heavy-ion collisionsJan 12 2011Jun 17 2011We investigate the influence of a temperature-dependent shear viscosity over entropy density ratio eta/s on the transverse momentum spectra and elliptic flow of hadrons in ultrarelativistic heavy-ion collisions. We find that the elliptic flow in sqrt(s_NN) ... More
Transition from ideal to viscous Mach cones in BAMPSAug 05 2012We investigate in a microscopical transport model the evolution of conical structures originating from the supersonic projectile moving through the matter of ultrarelativistic particles. Using different scenarios for the interaction between projectile ... More
An ultraweak formulation of the Kirchhoff-Love plate bending model and DPG approximationMay 20 2018We develop and analyze an ultraweak variational formulation for a variant of the Kirchhoff-Love plate bending model. Based on this formulation, we introduce a discretization of the discontinuous Petrov-Galerkin type with optimal test functions (DPG). ... More
Effect of temperature-dependent eta/s on flow anisotropiesDec 17 2011We investigate the effects of a temperature-dependent shear viscosity over entropy density ratio eta/s on the flow anisotropy coefficients v_2 and v_4 in ultrarelativistic heavy-ion collisions at RHIC and LHC. We find that v_4 is more sensitive to the ... More
Extracting $\hat{q}$ in event-by-event hydrodynamics and the centrality/energy puzzleMay 03 2017In our analysis, we combine event-by-event hydrodynamics, within the EKRT formulation, with jet quenching -ASW Quenching Weights- to obtain high-$p_T$ $R_{\rm AA}$ for charged particles at RHIC and LHC energies for different centralities. By defining ... More
Numerical tests of causal relativistic dissipative fluid dynamicsJul 15 2009We present numerical methods to solve the Israel-Stewart (IS) equations of causal relativistic dissipative fluid dynamics with bulk and shear viscosities. We then test these methods studying the Riemann problem in (1+1)-- and (2+1)-dimensional geometry. ... More
On phase diagram and the pseudogap state in a linear chiral homopolymer modelJan 21 2015Dec 23 2015The phase structure of a homopolymer chain is investigated in terms of a universal theoretical model, designed to describe the infrared limit of slow spatial variations. The effects of chirality are studied and compared with the influence of a short-range ... More
Weighted Norm Estimates and Representation Formulas for Rough Singular IntegralsJul 16 1998Weighted norm estimates and representation formulas are proved for non-homogeneous singular integrals with no regularity condition on the kernel and only an L log L integrability condition. The representation formulas involve averages over a star-shaped ... More
Wave Front Sets of Reductive Lie Group Representations IIMar 25 2014In this paper it is shown that the wave front set of a direct integral of singular, irreducible representations of a real, reductive algebraic group is contained in the singular set. Combining this result with the results of the first paper in this series, ... More
Percolation on Strings and the Cover-up of the c=1 DisasterOct 20 1993Feb 28 1995We study percolation on the worldsheets of string theory for $c=0,1/2,1$ and $2$. For $c<1$ we find that critical exponents measured from simulations agree quite well with the theoretical values. For $c=1$ we show how log corrections determined from the ... More
Self-field and magnetic-flux quantum mechanicsApr 06 2005Self-field and quantized magnetic-flux are employed to generate the quantum numbers n, m, and l of atomic physics. Wave-particle duality is shown to be a natural outcome of having a particle and its self-field.
Kostant's weight multiplicity formula and the Fibonacci numbersNov 28 2011It is well known that the dimension of a weight space for a finite dimensional representation of a simple Lie algebra is given by Kostant's weight multiplicity formula. We address the question of how many terms in the alternation contribute to the multiplicity ... More
Optimal angle of the holomorphic functional calculus for the classical Ornstein-Uhlenbeck operator on $L^p$Dec 20 2018We give a simple proof of the fact that the classical Ornstein-Uhlenbeck operator $L$ is R-sectorial of angle $arcsin|1-2/p|$ on $L^{p}(\mathbb{R}^{n},\exp(-|x|^2/2)dx)$ (for $1<p<\infty$). Applying the abstract holomorphic functional calculus theory ... More
Toss and Spin Juggling State GraphsMay 12 2014We review the state approach to toss juggling and extend the approach to spin juggling, a new concept. We give connections to current research on random juggling and describe a professional-level juggling performance that further demonstrates the state ... More
From neural PCA to deep unsupervised learningNov 28 2014Feb 02 2015A network supporting deep unsupervised learning is presented. The network is an autoencoder with lateral shortcut connections from the encoder to decoder at each level of the hierarchy. The lateral shortcut connections allow the higher levels of the hierarchy ... More
The Index Bundle for a Family of Dirac-Ramond OperatorsFeb 09 2012We study the index bundle of the Dirac-Ramond operator associated with a family $\pi: Z \to X$ of compact spin manifolds. We view this operator as the formal twisted Dirac operator $\dd \otimes \bigotimes_{n=1}^{\infty}S_{q^n}TM_{\C}$ so that its index ... More
A short proof of the thumbtack lemmaApr 17 2013We give a short proof of the main algebraic result of \cite{zilber2006covers}, also known as the `thumbtack lemma'.
Weight zero Eisenstein cohomology of Shimura varieties via Berkovich spacesAug 08 2012This brief article gives an alternative interpretation, based on a theorem of Berkovich, of the Eisenstein classes in the cohomology of Shimura varieties, used in forthcoming work of the author with K. W. Lan, R. Taylor, and J. Thorne.
Relativistic Shock Waves and Mach Cones in Viscous Gluon MatterApr 26 2010To investigate the formation and the propagation of relativistic shock waves in viscous gluon matter we solve the relativistic Riemann problem using a microscopic parton cascade. We demonstrate the transition from ideal to viscous shock waves by varying ... More
Non-resistive dissipative magnetohydrodynamics from the Boltzmann equation in the 14-moment approximationApr 14 2018Oct 14 2018We derive the equations of motion of relativistic, non-resistive, second-order dissipative magnetohydrodynamics from the Boltzmann equation using the method of moments. We assume the fluid to be composed of a single type of point-like particles with vanishing ... More
Upper semicontinuity of the lamination hullSep 30 2016Let $K \subseteq \mathbb{R}^{2 \times 2}$ be a compact set, let $K^{rc}$ be its rank-one convex hull, and let $L(K)$ be its lamination convex hull. It is shown that the mapping $K \to \overline{L(K)}$ is not upper semicontinuous on the diagonal matrices ... More
Comparison of Attitude Estimation Techniques for Low-cost Unmanned Aerial VehiclesFeb 24 2016Attitude estimation for small, low-cost unmanned aerial vehicles is often achieved using a relatively simple complementary filter that combines onboard accelerometers, gyroscopes, and magnetometer sensing. This paper explores the limits of performance ... More
The local Langlands conjecture for GL(n) over a p-adic field, n < pNov 29 1996Let F be a p-adic field and n a positive integer. The local Langlands conjecture asserts the existence of a bijection between irreducible admissible representations of GL(n,F) and n-dimensional admissible representations of the Weil-Deligne group of F. ... More
Classification of the monomial Cremona transformations of the planeJul 24 2014We classify all monomial planar Cremona maps by multidegree using recent methods developed by Aluffi. Following the main result, we prove several more properties of the set of these maps, and also extend the results to the more general `r.c. monomial' ... More
Monomial principalization in the singular settingOct 04 2013Apr 15 2014We generalize an algorithm by Goward for principalization of monomial ideals in nonsingular varieties to work on any scheme of finite type over a field. The normal crossings condition considered by Goward is weakened to the condition that components of ... More
Heat Kernels and CyclesMay 26 2005We use the heat kernel (on differential forms) on a compact Riemannian manifold to assign a real number to a k-tuple of cycles on the manifold satisfying certain conditions. If k is 2, this number is the ordinary topological linking number, an integer ... More
The Magellanic Bridge: The Nearest Purely Tidal Stellar PopulationDec 04 2006We report on observations of the stellar populations in twelve fields spanning the region between the Magellanic Clouds, made with the Mosaic-II camera on the 4-meter telescope at the Cerro-Tololo Inter-American Observatory. The two main goals of the ... More
Categoricity and covering spacesDec 10 2014This thesis develops some of the basic model theory of covers of algebraic curves. In particular, an equivalence between the good model-theoretic behaviour of the modular j-function, and the openness of certain Galois representations in the Tate-modules ... More
On the Shape Optimization of Flapping Wings and their Performance AnalysisNov 12 2012The present work is concerned with the shape optimization of flapping wings in forward flight. The analysis is performed by combining a gradient-based optimizer with the unsteady vortex lattice method (UVLM). We describe the UVLM implementation and provide ... More
Determination of the Shear Viscosity Relaxation Time at Weak and Strong CouplingAug 31 2011We investigate the microscopic origin of the relaxation time coefficient in relativistic fluid dynamics. We show that the extraction of the shear viscosity relaxation time via the gradient expansion is ambiguous and in general fails to give the correct ... More
Orthonormal Compactly Supported Wavelets with Optimal Sobolev RegularityJul 16 1998Numerical optimization is used to construct new orthonormal compactly supported wavelets with Sobolev regularity exponent as high as possible among those mother wavelets with a fixed support length and a fixed number of vanishing moments. The increased ... More
Algebraic proofs of some fundamental theorems in algebraic $K$-theoryNov 20 2013We present news proofs of the additivity, resolution and cofinality theorems for the algebraic $K$-theory of exact categories. These proofs are entirely algebraic, based on Grayson's presentation of higher algebraic $K$-groups via binary complexes.
Algorithms for Image Analysis and Combination of Pattern Classifiers with Application to Medical DiagnosisOct 18 2009Medical Informatics and the application of modern signal processing in the assistance of the diagnostic process in medical imaging is one of the more recent and active research areas today. This thesis addresses a variety of issues related to the general ... More
On the local Langlands correspondenceApr 22 2003The local Langlands correspondence for GL(n) of a non-Archimedean local field $F$ parametrizes irreducible admissible representations of $GL(n,F)$ in terms of representations of the Weil-Deligne group $WD_F$ of $F$. The correspondence, whose existence ... More
Testing rationality of coherent cohomology of Shimura varietiesDec 09 2012Let $G' \subset G$ be an inclusion of reductive groups whose real points have a non-trivial discrete series. Combining ergodic methods of Burger-Sarnak and the author with a positivity argument due to Li and the classification of minimal $K$-types of ... More
E1 Working Group Summary: Neutrino Factories and Muon CollidersNov 02 2001We are in the middle of a time of exciting discovery, namely that neutrinos have mass and oscillate. In order to take the next steps to understand this potential window onto what well might be the mechanism that links the quarks and leptons, we need both ... More
Computing Segre classes in arbitrary projective varietiesNov 21 2015Nov 26 2015We give an algorithm for computing Segre classes of subschemes of arbitrary projective varieties by computing degrees of a sequence of linear projections. Based on the fact that Segre classes of projective varieties commute with intersections by general ... More
On a linearized p-Laplace equation with rapidly oscillating coefficientsJun 15 2015Nov 19 2015Related to a conjecture of Tom Wolff, we solve a singular Neumann problem for a linearized p-Laplace equation in the unit disk.
On real growth and run-off companies in insurance ruin theoryNov 05 2015We study solvency of insurers in a comprehensive model where various economic factors affect the capital developments of the companies. The main interest is in the impact of real growth to ruin probabilities. The volume of the business is allowed to increase ... More
Elliptic flow in nuclear collisions at the Large Hadron ColliderJun 06 2008We use perfect-fluid hydrodynamical model to predict the elliptic flow coefficients in Pb + Pb collisions at the Large Hadron Collider (LHC). The initial state for the hydrodynamical calculation for central $A + A$ collisions is obtained from the perturbative ... More
Photon production from non-equilibrium QGP in heavy ion collisionsMar 15 2004We present a calculation of thermal photon production i.e. photons from secondary interactions among particles produced in heavy ion collisions at collider energies. This is done within the framework of hydrodynamics. We take into account the lack of ... More
Elliptic flow from pQCD + saturation + hydro modelMay 15 2007We have previously predicted multiplicities and transverse momentum spectra of hadrons for the most central LHC Pb+Pb collisions at $\sqrt{s_{NN}}=5.5$ TeV using initial state for hydrodynamic evolution from pQCD + final state saturation model. By considering ... More
Event-by-event distributions of azimuthal asymmetries in ultrarelativistic heavy-ion collisionsDec 05 2012Relativistic dissipative fluid dynamics is a common tool to describe the space-time evolution of the strongly interacting matter created in ultrarelativistic heavy-ion collisions. For a proper comparison to experimental data, fluid-dynamical calculations ... More
Massively parallel approximate Gaussian process regressionOct 18 2013Jun 04 2014We explore how the big-three computing paradigms -- symmetric multi-processor (SMC), graphical processing units (GPUs), and cluster computing -- can together be brought to bare on large-data Gaussian processes (GP) regression problems via a careful implementation ... More
Twisted Vortices in a Gauge Field TheoryJun 13 2001Nov 08 2001We inspect a particular gauge field theory model that describes the properties of a variety of physical systems, including a charge neutral two-component plasma, a Gross-Pitaevskii functional of two charged Cooper pair condensates, and a limiting case ... More
Automatically Stable Discontinuous Petrov-Galerkin Methods for Stationary Transport Problems: Quasi-Optimal Test Space NormJan 09 2012We investigate the application of the discontinuous Petrov-Galerkin (DPG) finite element framework to stationary convection-diffusion problems. In particular, we demonstrate how the quasi-optimal test space norm can be utilized to improve the robustness ... More
The Globular Cluster/Central Black Hole Connection in GalaxiesAug 27 2010We explore the relation between the total globular cluster population in a galaxy (N_GC) and the the mass of its central black hole (M_BH). Using a sample of 33 galaxies, twice as large as the original sample discussed by Burkert & Tremaine (2010), we ... More
The Halo Stars in NGC 5128. III: An Inner-Halo Field and the Metallicity DistributionApr 26 2002We present new HST/WFPC2 (V,I) photometry for the red-giant stars in NGC 5128 at a projected distance of 8 kpc from the galaxy center, which probe a mixture of its inner halo and outer bulge. The color-magnitude diagram shows an old red-giant branch which ... More
Dark Matter Halos in Galaxies and Globular Cluster Populations. II: Metallicity and MorphologyApr 13 2015An increasing body of data reveals a one-to-one linear correlation between galaxy halo mass and the total mass in its globular cluster (GC) population, M_{GCS} ~ M_h^{1.03 \pm 0.03}, valid over 5 orders of magnitude. We explore the nature of this correlation ... More
Lopsidependency in the Moser-Tardos framework: Beyond the Lopsided Lovasz Local LemmaOct 07 2016The Lopsided Lov\'{a}sz Local Lemma (LLLL) is a powerful probabilistic principle which has been used in a variety of combinatorial constructions. While originally a general statement about probability spaces, it has recently been transformed into a variety ... More
Light Hadron Spectroscopy and CharmoniumOct 17 2008During the last few years there has been a renaissance in charm and charmonium spectroscopy with higher precision measurements at the $\psi^{'}$ and $\psi(3770)$ coming from BESII and CLEOc and many new discoveries coming from B-factories. In this paper, ... More
Feedback models and stability analysis of three economic paradigmsMar 23 2013In this paper, simple mathematical models from Control Theory are applied to three very important economic paradigms, namely (a) minimum wages in self-regulating markets, (b) market-versus-true values and currency rates, and (c) government spending and ... More
NGC 5128: The Giant BeneathApr 27 2010I review what we have learned about the old stellar population of NGC 5128, the only large E galaxy close enough that we can currently observe individual stars as faint as the horizontal branch. Although its galaxy type is still a matter of debate for ... More
On-off Threshold Models of Social ContagionSep 10 2012We study binary state contagion dynamics on a social network where nodes act in response to the average state of their neighborhood. We model the competing tendencies of imitation and non-conformity by incorporating an off-threshold into standard threshold ... More
Universality of the Future Chronological BoundaryApr 04 1997Sep 26 1997The purpose of this note is to establish, in a categorical manner, the universality of the Geroch-Kronheimer-Penrose causal boundary when considering the types of causal structures that may profitably be put on any sort of boundary for a spacetime. Actually, ... More
Nonlocal Modulation of Entangled PhotonsAug 06 2008We consider ramifications of the use of high speed light modulators to questions of correlation and measurement of time-energy entangled photons. Using phase modulators, we find that temporal modulation of one photon of an entangled pair, as measured ... More
Topology of the Future Chronological Boundary: Universality for Spacelike BoundariesJul 19 1999Nov 10 1999A method is presented for imputing a topology for any chronological set, i.e., a set with a chronology relation, such as a spacetime or a spacetime with some sort of boundary. This topology is shown to have several good properties, such as replicating ... More
Symmetry Analysis of Multiferroic Co_3TeO_6Feb 16 2012A phenomenological explanation of the magnetoelectric behavior of Co_3TeO_6 is developed. We explain the second harmonic generation data and the magnetic field induced spontaneous polarization in the magnetically ordered phase below 20K.
Limits from CGRO/EGRET Data on the Use of Antimatter as a Power Source by Extraterrestrial CivilizationsDec 20 2001Jun 15 2002I argue that the existence of cold antimatter in bulk is not permitted by the Standard Model, so that if a gamma-ray signature from antiproton annihilation were to be detected, it must represent either new physics or the action of intelligence. Time variability ... More
p-adic measures and square roots of triple product L-functionsOct 23 1996Let p be a prime number, and let f, g, and h be three modular forms of weights $\kappa$, $\lambda$, and $\mu$ for $SL(2,\Bbb{Z})$. We suppose $\kappa \geq \lambda + \mu$. In joint work with Kudla, one of the authors obtained a formula for the normalized ... More
A Two Term Truncation of the Multiple Ising Model Coupled to 2d GravityFeb 06 1995We consider a model of p independent Ising spins on a dynamical planar phi-cubed graph. Truncating the free energy to two terms yields an exactly solvable model that has a third order phase transition from a pure gravity region (gamma=-1/2) to a tree-like ... More
Error-prone polymerase activity causes multinucleotide mutations in humansDec 05 2013Apr 29 2014About 2% of human genetic polymorphisms have been hypothesized to arise via multinucleotide mutations (MNMs), complex events that generate SNPs at multiple sites in a single generation. MNMs have the potential to accelerate the pace at which single genes ... More
Branching Brownian motion: Almost sure growth along unscaled pathsNov 11 2008We give new results on the growth of the number of particles in a dyadic branching Brownian motion which follow within a fixed distance of a path $f:[0,\infty)\to \mathbb{R}$. We show that it is possible to count the number of particles without rescaling ... More
Period relations and special values of Rankin-Selberg $L$-functionsAug 26 2016This is a survey of recent work on values of Rankin-Selberg $L$-functions of pairs of cohomological automorphic representations that are {\it critical} in Deligne's sense. The base field is assumed to be a CM field. Deligne's conjecture is stated in the ... More
Electromagnetically Induced Transparency and Quantum Heat EnginesNov 03 2016We describe how electromagnetically induced transparency may be used to construct a non-traditional near-ideal quantum heat engine as constrained by the Second Law. The engine is pumped by a thermal reservoir that may be either hotter or colder than that ... More
Powers of Ideals and Fibers of MorphismsJul 26 2008Let X\subset PP^n be a projective scheme over a field, and let phi:X --> Y be a finite morphism. Our main result is a formula in terms of global data for the maximum of the Castelnuovo-Mumford regularity of the fibers of \phi, considered as subschemes ... More
Scaling Radio Astronomy Signal Correlation on Heterogeneous Supercomputers Using Various Data Distribution MethodologiesMay 24 2013Next generation radio telescopes will require orders of magnitude more computing power to provide a view of the universe with greater sensitivity. In the initial stages of the signal processing flow of a radio telescope, signal correlation is one of the ... More
Knots in interactionFeb 19 1999Feb 24 1999We study the geometry of interacting knotted solitons. The interaction is local and advances either as a three-body or as a four-body process, depending on the relative orientation and a degeneracy of the solitons involved. The splitting and adjoining ... More
Gauge Vector Masses from Flat Connections?Oct 02 1995Oct 03 1995We suggest that four dimensional massive gauge vectors could be described by coupling ordinary Yang-Mills theory to a topological gauge theory. For this the coupling should excite a nontrivial degree of freedom from the topological theory, corresponding ... More
On the Formation of Galaxy Halos: Comparing NGC 5128 and the Local Group MembersAug 14 2001The metallicity distribution function (MDF) for the old red-giant stars in the halo of NGC 5128, the nearest giant elliptical galaxy, is virtually identical with the MDF for the old-disk stars in the LMC and also strongly resembles the halo MDF in M31. ... More
Bepcii and BesiiiAug 23 2008The Beijing Electron Collider has been upgraded (BEPCII) to a two-ring collider with a design luminosity of $1 \times 10^{33}$cm$^{-2}$ s$^{-1}$ at a center-of-mass energy of 3.78 GeV. It will operate between 2 and 4.6 GeV in the center of mass. With ... More
Recent BES results and the BESIII upgradeDec 17 2007Using 58 million $J/\psi$ and 14 million $\psi(2S)$ events collected by the BESII detector at the BEPC, branching fractions or upper limits for the decays $J/\psi$ and $\psi(2S) \to \Lambda \bar{\Lambda} \pi^0$ and $\Lambda \bar{\Lambda} \eta$ are measured, ... More
BEPCII and BESIIIJun 06 2006The Beijing Electron Collider is being upgraded (BEPCII) to a two-ring collider with a design luminosity of $1 \times 10^{33}$cm$^{-2}$ s$^{-1}$ at a center-of-mass energy of 3.89 GeV. It will operate between 2 and 4.2 GeV in the center of mass. With ... More
BES Results on J/psi decays and Charmonium TransitionsJul 20 2004Results are reported based on samples of 58 million $\jpsi$ and 14 million $\psip$ decays obtained by the BESII experiment. Improved branching fraction measurements are determined, including branching fractions for $\jpsi\to\ppp$, $\psip\ra \pi^0\J$, ... More
A Non-Commutative Unitary Analogue of Kirchberg's ConjectureAug 10 2016Sep 13 2016The $C^{\ast}$-algebra $\mathcal{U}_{nc}(n)$ is the universal $C^{\ast}$-algebra generated by $n^2$ generators $u_{ij}$ that make up a unitary matrix. We prove that Kirchberg's formulation of Connes' embedding problem has a positive answer if and only ... More
Search for New Particles Decaying to Dijets, Bottom Quarks, and Top Quarks at CDFJun 15 1995Jun 16 1995We present three searches for new particles at CDF. First, using 70 pb^-1 of data we search the dijet mass spectrum for resonances. There is an upward fluctuation near 550 GeV (2.6 sigma) with an angular distribution that is adequately described by either ... More
The Cluster and Large Scale Environments of Quasars at z<0.9Jan 27 2012In this thesis, I present an investigation into the environments of quasars with respect to galaxy clusters, and environment evolution with redshift and luminosity. The orientation of the quasar with respect to the major axis of the closest cluster was ... More
Rational Points on QuarticsSep 03 1998Let $S \subset \P^n$ be a smooth quartic hypersurface defined over a number field $K$. If $n \ge 4$, then for some finite extension $K'$ of $K$ the set $S(K')$ of $K'$-rational points of $S$ is Zariski dense.
Comment on "Dynamics of Weak First Order Phase Transitions"Nov 08 1995We comment on an earlier paper of M. Gleiser, regarding mechanisms of first-order phase transitions.
Spectroscopic Survey of Red Giants in the SMC. I: KinematicsJan 02 2006We present a spectroscopic survey of 2046 red giant stars, distributed over the central 4x2 kpc of the Small Magellanic Cloud (SMC). After fitting and removing a small velocity gradient across the SMC (7.9 km/s/deg oriented at 10 deg E of N), we measure ... More
Severi Degrees in Cogenus 3Apr 06 1995In this short note, a new computation of the degree of the locus of 3-nodal plane curves in the linear system of degree d plane curves is given. The answer is expressed as a tautological class on a blow-up of the Hilbert scheme of 3 points in the plane. ... More
Enumerating curves on rational surfaces: the rational fibration methodAug 22 1996A new, simple method to approach enumerative questions about rational curves on rational surfaces is described. Applications include a short proof of Kontsevich's formula for plane curves and a the solution of the analogous problem for the Hirzebruch ... More
PC algorithm for Gaussian copula graphical modelsJul 01 2012The PC algorithm uses conditional independence tests for model selection in graphical modeling with acyclic directed graphs. In Gaussian models, tests of conditional independence are typically based on Pearson correlations, and high-dimensional consistency ... More
Landau Theory of Tilting of Oxygen Octahedra in PerovskitesJun 13 2011The list of possible commensurate phases obtained from the parent tetragonal phase of Ruddlesden-Popper systems, A$_{n+1}$B$_n$C$_{3n+1}$ for general $n$ due to a single phase transition involving the reorienting of octahedra of C (oxygen) ions is reexamined ... More