Results for "Derek J. Phillips"

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Real-time Prediction of Automotive Collision Risk from Monocular VideoFeb 04 2019Many automotive applications, such as Advanced Driver Assistance Systems (ADAS) for collision avoidance and warnings, require estimating the future automotive risk of a driving scene. We present a low-cost system that predicts the collision risk over ... More
Simulating Emergent Properties of Human Driving Behavior Using Multi-Agent Reward Augmented Imitation LearningMar 14 2019Recent developments in multi-agent imitation learning have shown promising results for modeling the behavior of human drivers. However, it is challenging to capture emergent traffic behaviors that are observed in real-world datasets. Such behaviors arise ... More
The Automatic Galaxy Collision SoftwareAug 24 2009The key to understanding the physical processes that occur during galaxy interactions is dynamical modeling, and especially the detailed matching of numerical models to specific systems. To make modeling interacting galaxies more efficient, we have constructed ... More
The Solar Photospheric-to-Coronal Fe abundance from X-ray Fluorescence LinesDec 23 2011The ratio of the Fe abundance in the photosphere to that in coronal flare plasmas is determined by X-ray lines within the complex at 6.7~keV (1.9~\AA) emitted during flares. The line complex includes the He-like Fe (\fexxv) resonance line $w$ (6.70~keV) ... More
Highly ionized Fe X-ray lines at energies 7.7-8.6 keVSep 09 2008Fe XXV lines at 1.85 A (6.70 keV) and nearby Fe XXIV satellites have been widely used for determining the temperature of the hottest parts of solar flare and tokamak plasmas, though the spectral region is crowded and the lines are blended during flare ... More
The Influence of Policy Regimes on the Development and Social Implications of Privacy Enhancing TechnologiesSep 24 2001Oct 23 2001As privacy issues have gained social salience, entrepreneurs have begun to offer privacy enhancing technologies (PETs) and the U.S. has begun to enact privacy legislation. But "privacy" is an ambiguous notion. In the liberal tradition, it is an individualistic ... More
Why Abeta42 Is Much More Toxic Than Abeta40Oct 25 2018Amyloid precursor with 770 amino acids dimerizes and aggregates, as do its c terminal 99 amino acids and amyloid 40,42 amino acids fragments. The titled question has been discussed extensively, and here it is addressed further using thermodynamic scaling ... More
Ultra long range plasmonic waveguides using quasi two dimensional metallic layersJan 22 2007We calculate the bound plasmonic modes of a quantum metamaterial slab, comprised of multiple quasi two dimensional electron gas (Q2DEG) layers, whose thickness is much smaller than the optical wavelength. For the first order transverse magnetic (TM) optical ... More
Solar Neutrino OscillationsFeb 11 1994Invited review talk at the International Conference on Non-Accelerator Particle Physics (ICNAPP-94), Bangalore, India, 2-9 January 1994. Latex file.
Zigzag Filamentary Theory of Broken Symmetry of Neutron and Infrared Vibronic Spectra of YBa2Cu3O(6+x)Mar 07 2001Filamentary high-temperature superconductivity (HTSC) theory differs fundamentally from continuous HTSC theories because it emphasizes self-organized, discrete dopant networks and does not make the effective medium approximation (EMA). Analysis of neutron ... More
Nanodomain Structure and Function in HTSCFeb 14 2001Feb 16 2001The causes of high-temperature superconductivity (HTSC) are still mysterious, although more than 50,000 experiments have studied this subject. The most severe test of any microscopic theory is generally considered to be its ability to predict the results ... More
Verifying Public Keys without Trust: How Anonymity Can Guarantee Data IntegrityFeb 10 2016Despite the inroads that public-key cryptography has made on the web, the difficulty of key management has for the most part kept it out of the hands of the general public. With key-distribution software for PGP beginning to natively support the anonymizing ... More
Mutual information for examining correlations in DNAApr 07 2004This paper examines two methods for finding whether long-range correlations exist in DNA: a fractal measure and a mutual information technique. We evaluate the performance and implications of these methods in detail. In particular we explore their use ... More
Optimizing genetic algorithm strategies for evolving networksApr 07 2004This paper explores the use of genetic algorithms for the design of networks, where the demands on the network fluctuate in time. For varying network constraints, we find the best network using the standard genetic algorithm operators such as inversion, ... More
Over-Improved Stout-Link SmearingJan 08 2008A new over-improved stout-link smearing algorithm, designed to stabilise instanton-like objects, is presented. A method for quantifying the selection of the over-improvement parameter, $\epsilon$, is demonstrated. The new smearing algorithm is compared ... More
Aspects of QCD Vacuum StructureOct 12 2007The impact of dynamical fermions on the vacuum structure of QCD is explored. Of particular interest is the topological charge correlator, $<q(x) q(0) >$, where negative values at small $x$ reveal a sign-alternating layered structure to the topological-charge ... More
Where To Look: Focus Regions for Visual Question AnsweringNov 23 2015Jan 10 2016We present a method that learns to answer visual questions by selecting image regions relevant to the text-based query. Our method exhibits significant improvements in answering questions such as "what color," where it is necessary to evaluate a specific ... More
The conjugacy problem in hyperbolic groups for finite lists of group elementsNov 07 2011Nov 09 2011Let G be a word-hyperbolic group with given finite generating set, for which various standard structures and constants have been pre-computed. A (non-practical) algorithm is described that, given as input two lists A and B, each composed of m words in ... More
Linear groupoids and the associated wreath productsJan 24 2007A groupoid identity is said to be linear of length $2k$ if the same $k$ variables appear on both sides of the identity exactly once. We classify and count all varieties of groupoids defined by a single linear identity. For $k=3$, there are 14 nontrivial ... More
Impact of Dynamical Fermions on QCD Vacuum StructureJan 14 2008We examine how dynamical fermions affect both the UV and infrared structure of the QCD vacuum. We consider large $28^3 \times 96$ lattices from the MILC collaboration, using a gluonic definition of the topological charge density, founded on a new over-improved ... More
The varieties of loops of Bol-Moufang typeJan 24 2007A loop identity is of Bol-Moufang type if two of its three variables occur once on each side, the third variable occurs twice on each side, and the order in which the variables appear on both sides is the same, viz. $((xy)x)z=x(y(xz))$. Loop varieties ... More
The varieties of quasigroups of Bol-Moufang type: An equational reasoning approachJan 24 2007A quasigroup identity is of Bol-Moufang type if two of its three variables occur once on each side, the third variable occurs twice on each side, the order in which the variables appear on both sides is the same, and the only binary operation used is ... More
A scoop from groups: Equational foundations for loopsSep 17 2015Groups are usually axiomatized as algebras with an associative binary operation, a two-sided neutral element, and with two-sided inverses. We show in this note that the same simplicity of axioms can be achieved for some of the most important varieties ... More
Hemoglobin Strain Field Waves and Allometric FunctionalityMay 30 2016Hemoglobin (Hgb) forms tetramers (dimerized dimers), which enhance its globular stability and may also facilitate small gas molecule transport, as shown by recent all-atom Newtonian solvated simulations. Hydropathic bioinformatic scaling reveals many ... More
Hidden Thermodynamic Information in Protein Amino Acid Mutation TablesJan 11 2016We combine the standard 1992 20x20 substitution matrix based on block alignment, BLOSUM62, with the standard 1982 amino acid hydropathicity scale KD as well as the modern 2007 hydropathicity scale MZ, and compare the results. The 20-parameter KD and MZ ... More
C-loops: An introductionJan 24 2007C-loops are loops satisfying $x(y(yz))=((xy)y)z$. They often behave analogously to Moufang loops and they are closely related to Steiner triple systems and combinatorics. We initiate the study of C-loops by proving: (i) Steiner loops are C-loops, (ii) ... More
Modelling Alkali Line Absorption and Molecular Bands in Cool DAZsJan 05 2005Two peculiar stars showing an apparent extremely broadened and strong NaI D absorption have been discovered in surveys for cool white dwarfs by Oppenheimer et al. (2001) and Harris et al. (SDSS, 2003). We discuss the nature of these objects using PHOENIX ... More
The Extended Methanol Maser Emission in W51Jan 27 2004The European VLBI Network (EVN) has been used to make phase referenced, wide-field (several arcminute) spectral line observations of the 6.7-GHz methanol maser emission towards W51. In the W51main region, the bulk of the methanol is offset from an UCHII ... More
Topological derivation of shape exponents for stretched exponential relaxationMar 03 2004Oct 01 2004In homogeneous glasses, values of the important dimensionless stretched-exponential shape parameter beta are shown to be determined by magic (not adjusted) simple fractions derived from fractal configuration spaces of effective dimension d* by applying ... More
Role of the Wilson mass parameter in the overlap Dirac topological charge densityOct 15 2009Oct 27 2009The negative Wilson mass parameter is an input parameter to the overlap Dirac operator. We examine the extent to which the topological charge density, revealed by the overlap definition, depends on the value of the negative Wilson mass. A strong dependence ... More
Evolution of the Ubiquitin-Activating Enzyme Uba1 (E1)Feb 22 2017Ubiquitin tags diseased proteins and initiates an enzyme conjugation cascade, which has three stages. The first-stage enzyme Uba1 (E1) has evolved only modestly from slime mold to humans, and is > 14 times larger than Ub. Here we use critical point thermodynamic ... More
Supersymmetry PhenomenologyJun 16 1993We review some recent results and future prospects in the phenomenology of Supersymmmetry. We discuss the searches for superpartner states, the searches for Higgs bosons in the minimal SUSY model, and additional parameter constraints arising in SUSY-GUT ... More
The longitudinal response function of the deuteron in chiral effective field theoryMay 31 2013Oct 11 2013We use chiral effective field theory (EFT) to make predictions for the longitudinal electromagnetic response function of the deuteron, f_L, which is measured in d(e,e'N) reactions. In this case the impulse approximation gives the full chiral EFT result ... More
A covariant gauge-invariant three-dimensional description of relativistic bound-statesAug 15 1997A formalism is presented which allows covariant three-dimensional bound-state equations to be derived systematically from four-dimensional ones without the use of delta-functions. The amplitude for the interaction of a bound state described by these equations ... More
Interfacial ion solvation: Obtaining the thermodynamic limit from molecular simulationsJan 02 2018Aug 13 2018Inferring properties of macroscopic solutions from molecular simulations is complicated by the limited size of systems that can be feasibly examined with a computer. When long-ranged electrostatic interactions are involved, the resulting finite size effects ... More
Commutants of Bol loops of Odd OrderJul 14 2002In this note we show that the commutant of a Bol loop of odd order is a subloop.
Survey of Multiscale and Multiphysics Applications and CommunitiesAug 31 2012May 23 2013Multiscale and multiphysics applications are now commonplace, and many researchers focus on combining existing models to construct combined multiscale models. Here we present a concise review of multiscale applications and their source communities. We ... More
The gravitational field of a cubeJun 18 2012Large astronomical objects such as stars or planets, produce approximately spherical shapes due to the large gravitational forces, and if the object is rotating rapidly, it becomes an oblate spheroid. In juxtaposition to this, we conduct a thought experiment ... More
Physical-layer encryption on the public internet: a stochastic approach to the Kish-Sethuraman cipherJun 18 2013While information-theoretic security is often associated with the one-time pad and quantum key distribution, noisy transport media leave room for classical techniques and even covert operation. Transit times across the public internet exhibit a degree ... More
A fast method of crosstalk characterization for HxRG detectorsAug 02 2018HxRG detectors have crosstalk between amplifier channels at a scientifically relevant level. In principle, crosstalk signals can be fully calibrated and removed from data, but only if a full crosstalk matrix is measured for the detector. We present a ... More
Mesonic Width Effects on the Momentum Dependence of the Rho-Omega Mixing Matrix ElementApr 25 1995Mar 07 1996It is shown, in a model independent way, that the large difference in rho and omega widths gives rise to a new source of momentum dependence for the rho-omega mixing matrix element. The q^2 dependence arising due to the meson widths leads to a significant ... More
Part Localization using Multi-Proposal Consensus for Fine-Grained CategorizationJul 22 2015We present a simple deep learning framework to simultaneously predict keypoint locations and their respective visibilities and use those to achieve state-of-the-art performance for fine-grained classification. We show that by conditioning the predictions ... More
Numerical simulations of granular dynamics. I. Hard-sphere discrete element method and testsJun 11 2013We present a new particle-based (discrete element) numerical method for the simulation of granular dynamics, with application to motions of particles on small solar system body and planetary surfaces. The method employs the parallel N-body tree code pkdgrav ... More
Functions of multivector variablesAug 26 2014As is well known, the common elementary functions defined over the real numbers can be generalized to act not only over the complex number field but also over the skew (non-commuting) field of the quaternions. In this paper, we detail a number of elementary ... More
A New Algorithm for the Evaluation of Generalized B-splinesOct 14 2015In this paper we present a method for direct evaluation of generalized B-splines (GB-splines) via the local representation of these curves as piecewise functions. To accomplish this we introduce a local structure that makes GB-spline curves more amenable ... More
New QCD Sum Rules for In-Medium NucleonsNov 28 1995New QCD sum rules for nucleons in nuclear matter are derived from a mixed correlation function of spin-1/2 and spin-3/2 interpolating fields. These sum rules allow a determination of the scalar self-energy of the nucleon independent of the poorly known ... More
The Magnetic Association of Coronal Bright PointsOct 28 1998Several coronal bright points identified in a quiet region of the Sun from SOHO/EIT Fe XII images are found to have a time evolution from birth to decay which is extremely well correlated with the rise and fall of magnetic flux as determined from photospheric ... More
Relativistic bound-state equations in three dimensionsMar 07 1996May 16 1996Firstly, a systematic procedure is derived for obtaining three-dimensional bound-state equations from four-dimensional ones. Unlike ``quasi-potential approaches'' this procedure does not involve the use of delta-function constraints on the relative four-momentum. ... More
Search for Physics Beyond the Standard ModelMay 25 1993We survey some recent ideas and progress in looking for particle physics beyond the Standard Model, connected by the theme of Supersymmetry (SUSY). We review the success of SUSY-GUT models, the expected experimental signatures and present limits on SUSY ... More
F-quasigroups and generalized modulesDec 12 2005In math.GR/0510298, we showed that every F-quasigroup is linear over a special kind of Moufang loop called an NK-loop. Here we extend this relationship by showing an equivalence between the equational class of (pointed) F-quasigroups and the equational ... More
Axioms for trimedial quasigroupsOct 12 2003Jan 24 2004We give new equations that axiomatize the variety of trimedial quasigroups. We also improve a standard characterization by showing that right semimedial, left F-quasigroups are trimedial.
Analysis of Nematic Liquid Crystals with Disclination LinesJun 24 2011We investigate the structure of nematic liquid crystal thin films described by the Landau--de Gennes tensor-valued order parameter with Dirichlet boundary conditions of nonzero degree. We prove that as the elasticity constant goes to zero a limiting uniaxial ... More
Singlet quarks beyond the top at the Tevatron?May 04 1994The first evidence for the top quark at the Tevatron may indicate a cross section higher than the QCD expectation. We consider the possibility that isosinglet heavy quarks may be contributing to the signal and discuss ways of testing this possibility. ... More
Twisted cyclic theory and an index theory for the gauge invariant KMS state on Cuntz algebrasJan 30 2008Feb 29 2008This paper presents, by example, an index theory appropriate to algebras without trace. Whilst we work exclusively with the Cuntz algebras the exposition is designed to indicate how to develop a general theory. Our main result is an index theorem (formulated ... More
Collider Physics 1993Sep 09 1993These lectures survey the present situation and future prospects in selected areas of particle physics phenomenology: (1) the top quark, (2) the Higgs boson in the Standard Model, (3) strong $WW$ scattering, (4) supersymmetry, (5) the Higgs sector in ... More
Closing in on SupersymmetryMay 27 1993A survey is made of some recent ideas and progress in the phenomenological applications of Supersymmetry (SUSY). We describe the success of SUSY-GUT models, the expected experimental signatures and present limits on SUSY partner particles, and the phenomenology ... More
A Note on Trimedial QuasigroupsJun 13 2002The purpose of this brief note is to sharpen a result of Kepka about the axiomization of the variety of trimedial quasigroups.
Future Diffractive Structure Function Measurements at HERASep 26 1996The purposes and possibilities of future diffractive structure function measurements at HERA are presented. A review of the current range and accuracy of the measurement of $F_2^{D(3)}(\beta, x_p, Q^2)$ is presented and an estimate of the precision of ... More
New QCD Sum Rules for Nucleons in Nuclear MatterNov 07 1995Aug 29 1996Two new QCD sum rules for nucleons in nuclear matter are obtained from a mixed correlator of spin-1/2 and spin-3/2 interpolating fields. These new sum rules, which are insensitive to the poorly known four-quark condensates, provide additional information ... More
Kernel embedded nonlinear observational mappings in the variational mapping particle filterJan 29 2019Recently, some works have suggested methods to combine variational probabilistic inference with Monte Carlo sampling. One promising approach is via local optimal transport. In this approach, a gradient steepest descent method based on local optimal transport ... More
Rho-Omega Mixing via QCD Sum Rules with Finite Mesonic WidthsJul 13 1995Aug 29 1996Based on the analysis of both Borel and Finite-Energy QCD sum rules, the inclusion of finite mesonic widths leads to a dramatic effect on the predictions for the momentum dependence of the rho-omega mixing matrix element. It is shown that the rho-omega ... More
Wilson mass dependence of the overlap topological charge densityJul 06 2010Nov 04 2010The dependence of the overlap Dirac operator on the Wilson-mass regulator parameter is studied through calculations of the overlap topological charge densities at a variety of Wilson-mass values. In this formulation, the Wilson-mass is used in the negative ... More
An Unbiased Survey for Outflows in the W3 and W5 Star-Formation RegionsOct 15 2001During their birth all stars undergo periods of copious mass loss, frequently characterized by the occurrence of bipolar outflows. These outflows are believed to play a fundamental role in the star formation process. However the exact outflow generating ... More
A Geometric Approach for Computing Tolerance Bounds for Elastic Functional DataMay 29 2018Apr 25 2019We develop a method for constructing tolerance bounds for functional data with random warping variability. In particular, we define a generative, probabilistic model for the amplitude and phase components of such observations, which parsimoniously characterizes ... More
Parkes full polarization spectra of OH masers - II. Galactic longitudes 240 to 350Feb 12 2014Full polarization measurements of 1665 and 1667-MHz OH masers at 261 sites of massive star formation have been made with the Parkes radio telescope. Here we present the resulting spectra for 157 southern sources, complementing our previously published ... More
Parkes full polarization spectra of OH masers - I. Galactic longitudes 350 through the Galactic Centre to 41Feb 11 2014Full polarization measurements of 1665 and 1667-MHz OH masers at sites of massive star formation have been made with the Parkes 64-m radio telescope. Here we present the resulting spectra for 104 northerly sources. For more than 20 masers we made new ... More
Metal Abundances of KISS Galaxies. II. Nebular Abundances of Twelve Low-Luminosity Emission-Line GalaxiesJan 08 2004We present follow-up spectra of 39 emission-line galaxies (ELGs) from the KPNO International Spectroscopic Survey (KISS). Many targets were selected as potentially low metallicity systems based on their absolute B magnitudes and the metallicity-luminosity ... More
Further ways to distinguish single-lepton top quark signals from background at the TevatronSep 19 1994Further kinematical variables are suggested, in which to compare the putative leptonic $W$ plus 4-jet top quark signal with the QCD background. We show that the lepton rapidity asymmetry, the $p_T$-ranking of the tagged $b$-jet, the double-tag probability, ... More
Characteristic polynomials in real Ginibre ensemblesOct 08 2008Nov 10 2009We calculate the average of two characteristic polynomials for the real Ginibre ensemble of asymmetric random matrices, and its chiral counterpart. Considered as quadratic forms they determine a skew-symmetric kernel from which all complex eigenvalue ... More
Event shape criteria for single-lepton top signalsAug 03 1993Single-lepton plus jets signals from $t\bar t$ production at hadron colliders generally give more spherically symmetrical events than the principal backgrounds from $W$ production. We show that sphericity and aplanarity criteria, applied to lepton plus ... More
Testing two nuclear physics approximations used in the standard leaky box model for the spallogenic production of LiBeBFeb 05 2003The spallative production rates of Lithium, Beryllium and Boron (LiBeB) are a necessary component in any calculation of the evolution of these nuclei in the Galaxy. Previous calculations of these rates relied on two assumptions relating to the nuclear ... More
Single-Lepton Top Signals with a b-Tag at the TevatronDec 20 1993Events with a leptonic W-decay plus jets should contain top-quark signals, but a QCD W+jets background must be separated. We compare transverse W-momentum, jet multiplicity, and b-tagging separation criteria, and find that the main background after tagging ... More
The chiral Gaussian two-matrix ensemble of real asymmetric matricesNov 06 2009We solve a family of Gaussian two-matrix models with rectangular Nx(N+v) matrices, having real asymmetric matrix elements and depending on a non-Hermiticity parameter mu. Our model can be thought of as the chiral extension of the real Ginibre ensemble, ... More
The double-layer structure of overscreened surfaces by smeared-out ionsSep 02 2016Charge inversion occurring for smeared-out ions is accompanied by an oscillatory charge density profile, indicating a layering of an alternating charge. The layering effect, however, is not coextensive with charge inversion, and charge inversion accompanied ... More
On the discovery of social roles in large scale social systemsSep 16 2015The social role of a participant in a social system is a label conceptualizing the circumstances under which she interacts within it. They may be used as a theoretical tool that explains why and how users participate in an online social system. Social ... More
Central extensions of loop groups and obstruction to pre-quantizationApr 13 2010Sep 20 2010An explicit construction of a pre-quantum line bundle for the moduli space of flat G-bundles over a Riemann surface is given, where G is any non-simply connected compact simple Lie group. This work helps to explain a curious coincidence previously observed ... More
A Summary of Bulk Dynamics from Quark Matter 2009Jul 28 2009Oct 06 2009I review the recent progress in measuring elliptic flow in heavy ion collisions. These measurements show clearly how hydrodynamics starts to develop as the system size is increased from peripheral to central collisions. During this transition, the momentum ... More
Normaloid Weighted Composition Operators on $H^2$Nov 26 2017Jul 26 2018When \ph\ is an analytic self-map of the unit disk with Denjoy-Wolff point $a \in \D$, and $\rho(\W) = \psi(a)$, we give an exact characterization for when \W\ is normaloid. We also determine the spectral radius, essential spectral radius, and essential ... More
BiLipschitz embeddings of spheres into jet space Carnot groups not admitting Lipschitz extensionsDec 15 2017Sep 07 2018For all $k,n\ge 1$, we construct a biLipschitz embedding of $\mathbb{S}^n$ into the jet space Carnot group $J^k(\mathbb{R}^n)$ that does not admit a Lipschitz extension to $\mathbb{B}^{n+1}$. Let $f:\mathbb{B}^n\to \mathbb{R}$ be a smooth, positive function ... More
A variant of Gromov's problem on Hölder equivalence of Carnot groupsFeb 20 2017Jul 04 2017It is unknown if there exists a locally $\alpha$-H\"older homeomorphism $f:\mathbb{R}^3\to \mathbb{H}^1$ for any $\frac{1}{2}< \alpha\le \frac{2}{3}$, although the identity map $\mathbb{R}^3\to \mathbb{H}^1$ is locally $\frac{1}{2}$-H\"older. More generally, ... More
Generalized Log-sine integrals and Bell polynomialsMay 12 2017In this paper, we investigate the integral of $x^n\log^m(\sin(x))$ for natural numbers $m$ and $n$. In doing so, we recover some well-known results and remark on some relations to the log-sine integral $\operatorname{Ls}_{n+m+1}^{(n)}(\theta)$. Later, ... More
Mean-field electrostatics beyond the point-charge descriptionNov 27 2014This review explores the number of mean-field constructions for ions whose structure goes beyond the point-charge description, a representation used in the standard Poisson-Boltzmann equation. The exploration is motivated by a body of experimental work ... More
A Generalized Poincare Inequality for a Class of Constant Coefficient Differential OperatorsOct 11 2009We study first order differential operators with constant coefficients. The main question is under what conditions a generalized Poincar\'e inequality holds. We show that the constant rank condition is sufficient. The concept of the Moore-Penrose generalized ... More
Groupoid equivariant prequantizationNov 15 2016In their 2005 paper, C. Laurent-Gengoux and P. Xu define prequantization for pre-Hamiltonian actions of quasi-presymplectic Lie groupoids in terms of central extensions of Lie groupoids. The definition requires that the quasi-presymplectic structure be ... More
Basic equivariant gerbes on non-simply connected compact simple Lie groupsDec 22 2017This paper computes the obstruction to the existence of equivariant extensions of basic gerbes over non-simply connected compact simple Lie groups. By modifying a (finite dimensional) construction of Gaw\c{e}dzki-Reis [J. Geom. Phys. 50(1):28-55, 2004], ... More
Kinks, chains, and loop groups in the CP^n sigma modelsFeb 13 2009Jan 25 2010We consider topological solitons in the CP^n sigma models in two space dimensions. In particular, we study "kinks", which are independent of one coordinate up to a rotation of the target space, and "chains", which are periodic in one coordinate up to ... More
Viscous Corrections to Spectra, Elliptic Flow, and HBT RadiiSep 06 2002I compute the first viscous correction to the thermal distribution function. With this correction, I calculate the effect of viscosity on spectra, elliptic flow, and HBT radii. Indicating the breakdown of hydrodynamics, viscous corrections become of order ... More
Topological energy bounds for frustrated magnetsMar 18 2019Frustrated magnets are known to support two-dimensional topological solitons, called skyrmions. A continuum model for frustrated magnets has recently been shown to support both two-dimensional skyrmions and three-dimensional knotted solitons (hopfions). ... More
Compact symmetric spaces, triangular factorization, and Cayley coordinatesAug 18 2008Sep 14 2011Let U/K represent a connected, compact symmetric space, where theta is an involution of U that fixes K, phi: U/K to U is the geodesic Cartan embedding, and G is the complexification of U. We investigate the intersection of phi(U/K) with the Bruhat decomposition ... More
Some finite abelian group theory and some q-series identitiesMay 22 2014Jun 12 2014For a fixed odd prime $\ell$, we present new families of identities defined on various subposets of the poset of isomorphism classes of finite abelian $\ell$-groups, generalizing identities of Hall and Cohen-Lenstra. We also present a $q$-series identity. ... More
The large N limit of the Nahm transformFeb 15 2011We consider the large N limit of the Nahm transform, which relates charge N monopoles to solutions to the Nahm equation involving NxN matrices. In the large N limit the former approaches a magnetic bag, and the latter approaches a solution of the Nahm ... More
Operator algebras generated by left invertiblesSep 12 2018Operator algebras generated by partial isometries and their adjoints form the basis for some of the most well studied classes of C*-algebras. Motivated by questions from linear equations in Hilbert spaces (frame theory), we instigate a research program ... More
Pre-quantization of the Moduli Space of Flat G-Bundles over a SurfaceAug 09 2007Sep 29 2008For a simply connected, compact, simple Lie group G, the moduli space of flat G-bundles over a closed surface is known to be pre-quantizable at integer levels. For non-simply connected G, however, integrality of the level is not sufficient for pre-quantization, ... More
Random matrices, the Cohen-Lenstra heuristics, and roots of unityMay 23 2014The Cohen-Lenstra-Martinet heuristics predict the frequency with which a fixed finite abelian group appears as an ideal class group of an extension of number fields, for certain sets of extensions of a base field. Recently, Malle found numerical evidence ... More
Successive coefficients of convex functionsFeb 02 2015Mar 09 2015It is shown that for $f$ analytic and convex in $z\in D=\{z:|z|<1\}$ and given by $f(z)=z+\sum_{n=2}^{\infty}a_{n}z^{n}$, the difference of coefficients $||a_{3}|-|a_{2}||\le 25/48$ and $||a_{4}|-|a_{3}||\le 25/48$ . Both inequalities are sharp.
The double-layer structure of overscreened surfaces by smeared-out ionsSep 02 2016Nov 11 2016Charge inversion occurring for smeared-out ions is accompanied by an oscillatory charge density profile, indicating a layering of an alternating charge. The layering effect, however, is not coextensive with charge inversion, and charge inversion accompanied ... More
Ph. D. Thesis: Pre-quantization of the moduli space of flat G-bundlesApr 13 2010This thesis studies the pre-quantization of quasi-Hamiltonian group actions from a cohomological viewpoint. The compatibility of pre-quantization with symplectic reduction and the fusion product are established, and are used to understand the sufficient ... More
Hyperbolic calorons, monopoles, and instantonsMar 29 2007Sep 10 2008We construct families of SO(3)-symmetric charge 1 instantons and calorons on the space H^3 x R. We show how the calorons include instantons and hyperbolic monopoles as limiting cases. We show how Euclidean calorons are the flat space limit of this family. ... More
Chemical Freezeout in Heavy Ion CollisionsApr 08 2002We construct a hadronic equation of state consistent with chemical freezeout and discuss how such an equation of state modifies the radial and elliptic flow in a hydrodynamic + hadronic cascade model of relativistic heavy ion collisions at the SPS. Incorporating ... More
Dimension results for mappings of jet space Carnot groupsApr 24 2018We propose analogues of horizontal and vertical projections for model filiform jet space Carnot groups. Every pair consisting of the jet of a smooth function on $\mathbb{R}$ and a vertical hyperplane with first coordinate fixed provides a splitting of ... More