Results for "Sean R Giblin"

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Observation of low frequency spin dynamics in INVAR Fe$_{65}$Ni$_{35}$Mar 10 2016Jun 02 2016We present ferromagnetic neutron spin echo measurements and muon spin relaxation ($\mu$SR) measurements of the spin dynamics in the ordered phase of the metallic alloy INVAR Fe$_{65}$Ni$_{35}$. Both techniques display evidence of slow spin dynamics in ... More
Probing the magnetic ground state of the molecular Dysprosium triangleNov 04 2010We present zero field muon spin lattice relaxation measurements of a Dysprosium triangle molecular magnet. The local magnetic fields sensed by the implanted muons indicate the coexistence of static and dynamic internal magnetic fields below $T^* ~35$ ... More
Dipolar spin ice states with fast monopole hopping rate in CdEr$_2$X$_4$ (X = Se, S)May 30 2017Mar 20 2018Excitations in a spin ice behave as magnetic monopoles, and their population and mobility control the dynamics of a spin ice at low temperature. CdEr$_2$Se$_4$ is reported to have the Pauling entropy characteristic of a spin ice, but its dynamics are ... More
Mapping the first order magnetic transition in Yb$_2$Ti$_2$O$_7$May 12 2014The very nature of the ground state of the pyrochlore compound Yb$_2$Ti$_2$O$_7$ is much debated, as experimental results demonstrate evidence for both a disordered or a long-range ordered ground state. Indeed, the delicate balance of exchange interactions ... More
Partial magnetization plateau emerging from a quantum spin ice state in Tb2Ti2O7May 11 2011The quantum spin ice model applied to Tb2Ti2O7 predicts that magnetic fields applied along the [111] axis will induce a partial magnetization plateau [H. R. Molavian and M. J. P. Gingras, J. Phys.: Condens. Matter 21, 172201 (2009)]. We test this hypothesis ... More
Dilution effects in Ho$_{2-x}$Y$_x$Sn$_2$O$_7$: from the Spin Ice to the single-ion magnetOct 03 2008A study of the modifications of the magnetic properties of Ho$_{2-x}$Y$_x$Sn$_2$O$_7$ upon varying the concentration of diamagnetic Y$^{3+}$ ions is presented. Magnetization and specific heat measurements show that the Spin Ice ground-state is only weakly ... More
Nuclear spin assisted quantum tunnelling of magnetic monopoles in spin iceMar 26 2019Extensive work on single molecule magnets has identified a fundamental mode of relaxation arising from the nuclear-spin assisted quantum tunnelling of nearly independent and quasi-classical magnetic dipoles. Here we show that nuclear-spin assisted quantum ... More
Fluctuation spectroscopy as a probe of granular superconducting diamond filmsJun 19 2017We present resistance versus temperature data for a series of boron-doped nanocrystalline diamond films whose grain size is varied by changing the film thickness. Upon extracting the fluctuation conductivity near to the critical temperature we observe ... More
On the moduli space of A-infinity structuresOct 26 2014Nov 02 2014We study the moduli space of A-infinity structures on a topological space as well as the moduli space of A-infinity-ring structures on a fixed module spectrum. In each case we show that the moduli space sits in a homotopy fiber sequence in which the other ... More
Bridge numbers of knots in the page of an open bookFeb 14 2015Given any closed, connected, orientable $3$--manifold and integers $g\geq g(M), D > 0$, we show the existence of knots in $M$ whose genus $g$ bridge number is greater than $D$. These knots lie in a page of an open book decomposition of $M$, and the proof ... More
Observation of a superconducting glass state in granular superconducting diamondMar 05 2018The magnetic field dependence of the superconductivity in nanocrystalline boron doped diamond thin films is reported. Evidence of a glass state in the phase diagram is presented, as demonstrated by electrical resistance and magnetic relaxation measurements. ... More
Thermal-error regime in high-accuracy gigahertz single-electron pumpingMar 14 2017Nov 13 2017Single-electron pumps based on semiconductor quantum dots are promising candidates for the emerging quantum standard of electrical current. They can transfer discrete charges with part-per-million (ppm) precision in nanosecond time scales. Here, we employ ... More
Pre-Symmetry Sets of 3D shapesMay 05 2005The investigation of 3D euclidean symmetry sets (SS) and medial axis is an important area, due in particular to their various important applications. The pre-symmetry set of a surface M in 3-space (resp. smooth closed curve in 2D) is the set of pairs ... More
Global Structure of a Black-Hole Cosmos and its ExtremesApr 06 1993We analyze the global structure of a family of Einstein-Maxwell solutions parametrized by mass, charge and cosmological constant. In a qualitative classification there are: (i) generic black-hole solutions, describing a Wheeler wormhole in a closed cosmos ... More
Most likely paths to error when estimating the mean of a reflected random walkJun 24 2009Jun 25 2010It is known that simulation of the mean position of a Reflected Random Walk (RRW) $\{W_n\}$ exhibits non-standard behavior, even for light-tailed increment distributions with negative drift. The Large Deviation Principle (LDP) holds for deviations below ... More
The $\mathbb{Z}/2$-equivariant cohomology of complex projective spacesNov 18 2018Mar 06 2019In this article we compute the cohomology of complex projective spaces associated to finite dimensional representations of $\mathbb{Z}/2$ graded on virtual representations of its fundamental groupoid. This fully graded theory, unlike the classical $RO(G)$-graded ... More
Compact Deep Neural Networks for Computationally Efficient Gesture Classification From Electromyography SignalsJun 22 2018Apr 13 2019Machine learning classifiers using surface electromyography are important for human-machine interfacing and device control. Conventional classifiers such as support vector machines (SVMs) use manually extracted features based on e.g. wavelets. These features ... More
Bridge spectra of twisted torus knotsMar 25 2014We compute the genus zero bridge numbers and give lower bounds on the genus one bridge numbers for a large class of sufficiently generic hyperbolic twisted torus knots. As a result, the bridge spectra of these knots have two gaps which can be chosen to ... More
Approximating exponential family models (not single distributions) with a two-network architectureMar 18 2019Recently much attention has been paid to deep generative models, since they have been used to great success for variational inference, generation of complex data types, and more. In most all of these settings, the goal has been to find a particular member ... More
Estimating Loynes' exponentOct 28 2009Loynes' distribution, which characterizes the one dimensional marginal of the stationary solution to Lindley's recursion, possesses an ultimately exponential tail for a large class of increment processes. If one can observe increments but does not know ... More
μSR Study of Spin Dynamics in LiY$_{1-x}$Ho$_{x}$F$_{4}$Mar 02 2011We present zero-field {\mu}SR measurements for LiY$_{1-x}$Ho$_{x}$F$_{4}$ samples with x = 0.0017, 0.0085, 0.0406, and 0.0855. We characterize the dynamics associated with the formation of the (F-{\mu}-F)$^{-1}$ complex by comparing our data to Monte ... More
Vertices and inflexions of plane sections of surfaces in R^3Feb 25 2005Oct 07 2005We investigate the behaviour of vertices and inflexions on 1-parameter families of curves on smooth surfaces in the 3-space, which include a singular member. In particular, we discuss the context where the curves evolve as sections of a smooth surface ... More
Evolution of spin relaxation processes in LiY$_{1-x}$Ho$_x$F$_4$ with increasing x studied via AC-susceptibility and muon spin relaxationJul 12 2012We present measurements of magnetic field and frequency dependences of the low temperature (T = 1.8 K) AC-susceptibility, and temperature and field dependences of the longitudinal field positive muon spin relaxation ({\mu}SR) for LiY$_{1-x}$Ho$_x$F$_4$ ... More
Dynamic behavior of magnetic avalanches in the spin-ice compound Dy$_2$Ti$_2$O$_7$Jun 11 2014Avalanches of the magnetization, that is to say an abrupt reversal of the magnetization at a given field, have been previously reported in the spin-ice compound Dy$_{2}$Ti$_{2}$O$_{7}$. This out-of-equilibrium process, induced by magneto-thermal heating, ... More
Calculating electron momentum densities and Compton profiles using the linear tetrahedron methodNov 13 2014A method for computing electron momentum densities and Compton profiles from ab initio calculations is presented. Reciprocal space is divided into optimally-shaped tetrahedra for interpolation, and the linear tetrahedron method is used to obtain the momentum ... More
Asynchronous and Dynamic Coverage Control Scheme for Persistent Surveillance MissionsSep 17 2016A decomposition-based coverage control scheme is proposed for multi-agent, persistent surveillance missions operating in a communication-constrained, dynamic environment. The proposed approach decouples high-level task assignment from low-level motion ... More
How to Draw Graphs: Seeing and Redrafting Large Networks in Security and BiologyMar 03 2014A graph is a mathematical object consisting of a set of vertices and a set of edges connecting vertices. Graphs can be drawn on paper in various ways, but until recently all published methods of drawing graphs have had undesirable properties: (i) for ... More
Creation of long-term coherent optical memory via controlled nonlinear interactions in Bose-Einstein condensatesSep 17 2009Dec 07 2009A Bose-Einstein condensate confined in an optical dipole trap is used to generate long-term coherent memory for light, and storage times of more than one second are observed. Phase coherence of the condensate as well as controlled manipulations of elastic ... More
A Complete Surface Integral Method for Broadband Modeling of 3D Interconnects in Stratified MediaOct 09 2018Mar 07 2019A surface integral equation solver is proposed for fast and accurate simulation of interconnects embedded in stratified media. A novel technique for efficient computation of the multilayer Green's function is proposed. Using the Taylor expansion of Bessel ... More
Planet-planet scattering as the source of the highest eccentricity exoplanetsMar 06 2019Most giant exoplanets discovered by radial velocity surveys have much higher eccentricities than those in the Solar System. The planet-planet scattering mechanism has been shown to match the broad eccentricity distribution, but the highest-eccentricity ... More
Are we there yet? Understanding the challenges faced in complying with the General Data Protection Regulation (GDPR)Aug 22 2018The EU General Data Protection Regulation (GDPR), enforced from 25th May 2018, aims to reform how organisations view and control the personal data of private EU citizens. The scope of GDPR is somewhat unprecedented: it regulates every aspect of personal ... More
A Hierarchy of Scheduler Classes for Stochastic AutomataOct 16 2017Stochastic automata are a formal compositional model for concurrent stochastic timed systems, with general distributions and non-deterministic choices. Measures of interest are defined over schedulers that resolve the nondeterminism. In this paper we ... More
Heat capacity measurements on FeAs-based compounds: a thermodynamic probe of electronic and magnetic statesNov 15 2008We report heat capacity measurements of the pnictide materials SmFeAsO$_{1-x}$F$_x$, NdFeAsO, LaFeAsO$_{1-x}$F$_x$ and LiFeAs. For SmFeAsO$_{1-x}$F$_x$, with x close to 0.1, we use 3 He measurements to demonstrate a transfer of entropy from the peak at ... More
Near Infrared High Resolution Spectroscopy and Spectro-astrometry of Gas in Disks around Herbig Ae/Be StarsMar 10 2015In this review, we describe how high resolution near infrared spectroscopy and spectro-astrometry have been used to study the disks around Herbig~Ae/Be stars. We show how these tools can be used to identify signposts of planet formation and elucidate ... More
Dark Matter and Dark RadiationOct 28 2008Dec 16 2008We explore the feasibility and astrophysical consequences of a new long-range U(1) gauge field ("dark electromagnetism") that couples only to dark matter, not to the Standard Model. The dark matter consists of an equal number of positive and negative ... More
Asynchronous and Dynamic Coverage Control Scheme for Persistent Surveillance MissionsSep 17 2016Feb 15 2017A decomposition-based coverage control scheme is proposed for multi-agent, persistent surveillance missions operating in a communication-constrained, dynamic environment. The proposed approach decouples high-level task assignment from low-level motion ... More
Critical branching processes in memcomputingApr 09 2019Memcomputing is a novel computing paradigm that employs time non-locality (memory) to solve combinatorial optimization problems. It can be realized in practice by means of non-linear dynamical systems whose point attractors represent the solutions of ... More
Zig-zag ladders with staggered magnetic chirality in S = 3/2 compound beta-CaCr2O4Jun 18 2009The crystal and magnetic structures of the S = 3/2 chain antiferromagnet beta-CaCr2O4 have been investigated by means of specific heat, magnetization, muon relaxation and neutron powder diffraction between 300K and 1.5K. Owing to the original topology ... More
Stripe disorder and dynamics in the hole-doped antiferromagnetic insulator La5/3Sr1/3CoO4Jan 22 2013Jan 16 2014We report on an investigation into the dynamics of the stripe phase of La5/3Sr1/3CoO4, a material recently shown to have an hour-glass magnetic excitation spectrum. A combination of magnetic susceptibility, muon-spin relaxation and nuclear magnetic resonance ... More
Quantitative analysis of the interaction between a dc SQUID and an integrated micromechanical doubly clamped cantileverFeb 08 2019Based on the superconducting quantum interference device (SQUID) equations described by the resistively- and capacitively-shunted junction model coupled to the equation of motion of a damped harmonic oscillator, we provide simulations to quantitatively ... More
Gigahertz quantized charge pumping in graphene quantum dotsJul 27 2012Single electron pumps are set to revolutionize electrical metrology by enabling the ampere to be re-defined in terms of the elementary charge of an electron. Pumps based on lithographically-fixed tunnel barriers in mesoscopic metallic systems and normal/superconducting ... More
Cosmological Simulations for Combined-Probe Analyses: Covariance and Neighbour-Exclusion BiasMay 11 2018Oct 10 2018We present a public suite of weak lensing mock data, extending the Scinet Light Cone Simulations (SLICS) to simulate cross-correlation analyses with different cosmological probes. These mocks include KiDS-450- and LSST-like lensing data, cosmic microwave ... More
NIR Spectroscopy of the HAeBe Star HD 100546: III. Further Evidence of an Orbiting Companion?Sep 02 2014We report high resolution NIR spectroscopy of CO and OH emission from the Herbig Be star HD100546. We discuss how our results bear striking resemblance to several theoretically predicted signposts of giant planet formation. The properties of the CO and ... More
Gravitational Waves From the End of Inflation: Computational StrategiesDec 18 2007Parametric resonance or preheating is a plausible mechanism for bringing about the transition between the inflationary phase and a hot, radiation dominated universe. This epoch results in the rapid production of heavy particles far from thermal equilibrium ... More
BiLipschitz decomposition of Lipschitz maps between Carnot groupsJan 19 2015Aug 29 2015Let $f : G \to H$ be a Lipschitz map between two Carnot groups. We show that if $B$ is ball of $G$, then there exists a subset $Z \subset B$, whose image in $H$ under $f$ has small Hausdorff content, such that $B \backslash Z$ can be decomposed into a ... More
Coarse differentiation and quantitative nonembeddability for Carnot groupsApr 24 2013Jun 18 2013We give lower bound estimates for the macroscopic scale of coarse differentiability of Lipschitz maps from a Carnot group with the Carnot-Carath\'{e}odory metric $(G,\dcc)$ to a few different classes of metric spaces. Using this result, we derive lower ... More
On the geometry of almost $\mathcal{S}$-manifoldsMar 23 2011Oct 20 2011An $f$-structure on a manifold $M$ is an endomorphism field $\phi$ satisfying $\phi^3+\phi=0$. We call an $f$-structure {\em regular} if the distribution $T=\ker\phi$ is involutive and regular, in the sense of Palais. We show that when a regular $f$-structure ... More
Summary of Heavy Ion TheorySep 15 1994Sep 20 1994Can we study hot QCD using nuclear collisions? Can we learn about metallic hydrogen from the impact of comet Shoemaker-Levy 9 on Jupiter? The answer to both questions may surprise you! I summarize progress in relativistic heavy ion theory reported at ... More
Strange Disoriented Chiral CondensateApr 25 2002Disoriented chiral condensate can produce novel fluctuations of kaons as well as pions. Robust statistical observables can be used to extract the novel fluctuations from background contributions in K-short and K-charged correlation measurements in nuclear ... More
Dynamics of Chiral Symmetry Breaking in Nuclear CollisionsJul 25 1994Measurements of disoriented chiral condensates in heavy ion collisions at RHIC and the LHC can yield fundamental information on the nature of the QCD phase transition. I review theoretical efforts to understand the evolution of the condensate and present ... More
The Large Energy Expansion for B Decays: Soft Collinear Effective TheorySep 11 2003I this talk I give an introduction to the soft collinear effective theory by considering in detail the decay rate for $B \to X_s \gamma$ near the endpoint.
The Resummed Photon Spectrum in Radiative Upsilon Decays (And More)Sep 01 2003In this talk I present the results of two calculations that make use of Non-Relativistic QCD and the newly developed Soft-Collinear Effective Theory. The first process considered is inclusive radiative $\Upsilon$ decay. The second process considered is ... More
Half-wave Plates for the Spider Cosmic Microwave Background PolarimeterFeb 11 2014Spider is a balloon-borne array of six telescopes that will observe the Cosmic Microwave Background. The 2400 antenna-coupled bolometers in the instrument will make a polarization map of the CMB with ~degree resolution at 150 GHz and 95 GHz. Polarization ... More
Deep Neural Network EnsemblesApr 11 2019Current deep neural networks suffer from two problems; first, they are hard to interpret, and second, they suffer from overfitting. There have been many attempts to define interpretability in neural networks, but they typically lack causality or generality. ... More
Betti Numbers of Graph IdealsOct 05 2004In this thesis we investigate certain types of monomial ideals of polynomial rings over fields. We are interested in minimal free resolutions of these ideals (or equivalently the quotients of the polynomial ring by the ideals) considered as modules over ... More
The Bernstein presentation for general connected reductive groupsDec 28 2013Nov 10 2014Let F be a non-Archimedean local field and let G be a connected reductive affine algebraic F-group. Let I be an Iwahori subgroup of G(F) and denote by H(G; I) the Iwahori-Hecke algebra, i.e. the convolution algebra of complex-valued functions on G(F) ... More
Definability Aspects of the Denjoy IntegralSep 11 2016The Denjoy integral is an integral that extends the Lebesgue integral and can integrate any derivative. In this paper, it is shown that the graph of the indefinite Denjoy integral $f\mapsto \int_a^x f$ is a coanalytic non-Borel relation on the product ... More
Optimal preconditioners for systems defined by functions of Toeplitz matricesFeb 10 2018We propose several circulant preconditioners for systems defined by some functions $g$ of Toeplitz matrices $A_n$. In this paper we are interested in solving $g(A_n)\mathbf{x}=\mathbf{b}$ by the preconditioned conjugate method or the preconditioned minimal ... More
Commuting probabilities of finite groupsNov 04 2014Jun 24 2015The commuting probability of a finite group is defined to be the probability that two randomly chosen group elements commute. Let P \subset (0,1] be the set of commuting probabilities of all finite groups. We prove that every point of P is nearly an Egyptian ... More
On the universality of the nonstationary idealApr 19 2017Sep 19 2017Burke \cite{MR1472122} proved that the generalized nonstationary ideal, denoted NS, is universal in the following sense: every normal ideal, and every tower of normal ideals of inaccessible height, is a canonical Rudin-Keisler projection of the restriction ... More
Gravitational Wave Production At The End Of InflationDec 11 2006Sep 20 2007We consider gravitational wave production due to parametric resonance at the end of inflation, or ``preheating''. This leads to large inhomogeneities which source a stochastic background of gravitational waves at scales inside the comoving Hubble horizon ... More
The Log-Convex Density Conjecture and vertical surface area in warped productsJul 22 2011Dec 22 2014We examine the vertical component of surface area in the warped product of a Euclidean interval and a fiber manifold with product density. We determine general conditions under which vertical fibers minimize vertical surface area among regions bounding ... More
Transcendence of the Hodge-Tate filtrationOct 17 2016For $C$ a complete algebraically closed extension of $\mathbb{Q}_p$, we show that a one-dimensional $p$-divisible group $G/ \mathcal{O}_C$ can be defined over a complete discretely valued subfield $L \subset C$ with Hodge-Tate period ratios contained ... More
Generators, Relations and Symmetries in Pairs of 3x3 Unimodular MatricesJan 06 2006Jan 23 2007Denote the free group on two letters by F2 and the SL(3,C)-representation variety of F2 by R = Hom(F2, SL(3,C)). There is a SL(3,C)-action on the coordinate ring of R, and the geometric points of the subring of invariants is an affine variety X. We determine ... More
Quantitative bounds in the polynomial Szemerédi theorem: the homogeneous caseSep 29 2014Feb 19 2017We obtain quantitative bounds in the polynomial Szemer\'edi theorem of Bergelson and Leibman, provided the polynomials are homogeneous and of the same degree. Such configurations include arithmetic progressions with common difference equal to a perfect ... More
Circulant preconditioners for functions of Hermitian Toeplitz matricesJul 28 2018Circulant preconditioners for functions of matrices have been recently of interest. In particular, several authors proposed the use of the optimal circulant preconditioners as well as the superoptimal circulant preconditioners in this context and numerically ... More
Obtaining the One-Holed Torus from Pants: Duality in an SL(3,C)-Character VarietyMar 25 2008The SL(3,C)-representation variety R of a free group F arises naturally by considering surface group representations for a surface with boundary. There is a SL(3,C)-action on the coordinate ring of R. The geometric points of the subring of invariants ... More
Conjugacy classes of non-translations in affine Weyl groups and applications to Hecke algebrasJun 21 2013Nov 11 2014Let W be an Iwahori-Weyl group of a connected reductive group G over a non-archimedean local field. I prove that if w is an element of W that does not act on the corresponding apartment of G by a translation then one can apply to w a sequence of conjugations ... More
On the geometric quantization of contact manifoldsSep 10 2009Mar 24 2011Suppose that $(M,E)$ is a compact contact manifold, and that a compact Lie group $G$ acts on $M$ transverse to the contact distribution $E$. In an earlier paper, we defined a $G$-transversally elliptic Dirac operator $\dirac$, constructed using a Hermitian ... More
Minimal Affine Coordinates for SL(3,C) Character Varieties of Free GroupsSep 27 2007Jul 03 2008Let X be the moduli of SL(3,C) representations of a rank r free group. In this paper we determine minimal generators of the coordinate ring of X. This at once gives explicit global coordinates for the moduli and determines the dimension of the moduli's ... More
Fragments of Frege's Grundgesetze and Gödel's Constructible UniverseJul 15 2014Jun 07 2015Frege's Grundgesetze was one of the 19th century forerunners to contemporary set theory which was plagued by the Russell paradox. In recent years, it has been shown that subsystems of the Grundgesetze formed by restricting the comprehension schema are ... More
Stratified $β$-numbers and traveling salesman in Carnot groupsFeb 08 2019We introduce a modified version of P. Jones's $\beta$-numbers for Carnot groups which we call stratified $\beta$-numbers. We show that an analogue of Jones's traveling salesman theorem on 1-rectifiability of sets holds for any Carnot group if we replace ... More
Canonical bases for the quantum enveloping algebra of gl(m|1) and its modulesMay 13 2016We construct a crystal basis for the negative half of the quantum group U associated to the standard super Cartan datum of gl(m|1), which is compatible with known crystals on Kac modules and simple modules. We show that these crystals admit globalization ... More
Quantum osp(1|2n) knot invariants are the same as quantum so(2n+1) knot invariantsSep 11 2015We show that the quantum covering group associated to osp(1|2n) has an associated colored quantum knot invariant \`a la Reshetikhin-Turaev, which specializes to a quantum knot invariant for osp(1|2n), and to the usual quantum knot invariant for so(1+2n). ... More
Quantum supergroups IV. The modified formDec 17 2013Apr 23 2014We construct a canonical basis for a class of tensor product modules of a quantum covering group associated to a Kac-Moody Lie superalgebra of anisotropic type, and use these bases to construct a canonical basis for the modified form of a quantum covering ... More
A feasible roadmap to identifying significant intercellular genomic heterogeneity in deep sequencing dataOct 28 2013Sep 27 2014Intercellular heterogeneity serves as both a confounding factor in studying individual clones and an information source in characterizing any heterogeneous tissues, such as blood, tumor systems. Due to inevitable sequencing errors and other sample preparation ... More
A Wide-field Survey of Two Z~0.5 Galaxy Clusters: Identifying the Physical Processes Responsible for the Observed Transformation of Spirals into S0sJul 27 2007We present new results from our comprehensive comparative survey of two massive, intermediate redshift galaxy clusters, Cl0024+17 (z=0.39) and MS0451-03 (z=0.54). We identify and study several key classes of `transition objects' whose stellar populations ... More
The X-ray Transient 2XMMi J003833.3+402133: A Candidate Magnetar at High Galactic LatitudeAug 02 2011Aug 15 2012We present detailed analysis of the transient X-ray source 2XMMi J003833.3+402133 detected by XMM-Newton in January 2008 during a survey of M 31. The X-ray spectrum is well fitted by either a steep power law plus a blackbody model or a double blackbody ... More
Consistency of post-Newtonian waveforms with numerical relativityDec 04 2006Oct 29 2007General relativity predicts the gravitational wave signatures of coalescing binary black holes. Explicit waveform predictions for such systems, required for optimal analysis of observational data, have so far been achieved using the post-Newtonian (PN) ... More
Towards a Taxonomical Consensus: Diversity and Richness Inference from Large Scale rRNA gene AnalysisMar 25 2010Population analysis is persistently challenging but important, leading to the determination of diversity and function prediction of microbial community members. Here we detail our bioinformatics methods for analyzing population distribution and diversity ... More
Extending fields in a level set method by solving a biharmonic equationApr 28 2017We present an approach for computing extensions of velocities or other fields in level set methods by solving a biharmonic equation. The approach differs from other commonly used approaches to velocity extension because it deals with the interface fully ... More
Chiral Dynamics in Photo-Pion Physics: Theory, Experiment, and Future Studies at the HI$γ$S FacilityFeb 20 2009A review of photo-pion experiments on the nucleon in the near threshold region is presented. Comparisons of the results are made with the predictions of the low energy theorems of QCD calculated using chiral perturbation theory (ChPT) which is based on ... More
Dynamics of a Ferromagnetic Particle Levitated Over a SuperconductorOct 20 2018Feb 25 2019Under conditions where the angular momentum of a ferromagnetic particle is dominated by intrinsic spin, applied torque is predicted to cause gyroscopic precession of the particle. If the particle is sufficiently isolated from the environment, a measurement ... More
Vacancies, disorder-induced smearing of the electronic structure, and its implications for the superconductivity of anti-perovskite MgC$_{0.93}$Ni$_{2.85}$Aug 31 2017The anti-perovskite superconductor MgC$_{0.93}$Ni$_{2.85}$ was studied using high-resolution x-ray Compton scattering combined with electronic structure calculations. Compton scattering measurements were used to determine experimentally a Fermi surface ... More
An equivariant index formula for almost-CR manifoldsOct 02 2008Feb 01 2009We consider a consider the case of a compact manifold M, together with the following data: the action of a compact Lie group H and a smooth H-invariant distribution E, such that the H-orbits are transverse to E. These data determine a natural equivariant ... More
Power operations in the Kunneth spectral sequence and commutative HFp-algebrasFeb 22 2016In this paper, we prove the multiplicativity of the K\"unneth spectral sequence. This is established by an analogue of the Comparison Theorem from homological algebra, which we suspect may be useful for other spectral sequences. This multiplicativity ... More
Tree Oriented Data AnalysisSep 19 2014Sep 22 2014Complex data objects arise in many areas of modern science including evolutionary biology, nueroscience, dynamics of gene expression and medical imaging. Object oriented data analysis (OODA) is the statistical analysis of datasets of complex objects. ... More
Charmonium Suppression in Nuclear CollisionsSep 25 1996Measurements of $\psi$ and $\psi'$ production from experiment NA50 at the CERN SPS are compared to predictions based on a hadronic model of charmonium suppression by Vogt and myself. Data on centrality dependence and total cross sections are in good accord ... More
Extraordinary Baryon Fluctuations and the QCD Tricritical PointAug 24 1999The dynamic separation into phases of high and low baryon density in a heavy ion collision can enhance fluctuations of the net rapidity density of baryons compared to model expectations. We show how these fluctuations arise and how they can survive through ... More
Soft Collinear Effective Theory: An OverviewJul 22 2009In this talk I give an overview of soft collinear effective theory (SCET), including a discussion of some recent advances. First, I briefly cover the foundation upon which SCET is built, namely QCD factorization, and review the theoretical framework of ... More
Determining Color-Octet psi-Production Matrix Elements from gamma p and e p ProcessesOct 15 1996We calculated, within the NRQCD factorization formalism, the leading color-octet contributions to psi production in photon-nucleon and electron-nucleon collisions. The expressions obtained depend on the NRQCD matrix elements <O^{psi}_8(^1S_0)> and <O^{psi}_8(^3P_J)>. ... More
NRQCD Prediction for the Polarization of the J/psi Produced from b-decayAug 27 1996Presented at the Meeting of the Division of Particles and Fields, August 1996, in Minneapolis. The work presented here is based upon a recent paper (hep-ph/9608413) done in collaboration with Oscar F. Hernandez, Ivan Maksymyk, and Helene Nadeau. The NRQCD ... More
The AdS/CFT partition function, AdS as a lift of a CFT, and holographic RG flow from conformal deformationsOct 21 2015Jan 13 2016Conformal deformations manifest in the AdS/CFT correspondence as boundary conditions on the AdS field. Heretofore, double-trace deformations have been the primary focus in this context. To better understand multitrace deformations, we revisit the relationship ... 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
Predicativity, the Russell-Myhill Paradox, and Church's Intensional LogicJun 07 2015This paper sets out a predicative response to the Russell-Myhill paradox of propositions within the framework of Church's intensional logic. A predicative response places restrictions on the full comprehension schema, which asserts that every formula ... More
Conjugation of Transitive Permutation Pairs and Dessins d'EnfantsJan 31 2017Apr 06 2017Let E be a finite set. Given permutations x and y of E that together generate a transitive subgroup, for which s is it true that x and the conjugate of y by s also generate a transitive subgroup? Such transitive permutation pairs encode dessins d'enfants, ... More
The Strength of Abstraction with Predicative ComprehensionJul 15 2014Nov 13 2015Frege's theorem says that second-order Peano arithmetic is interpretable in Hume's Principle and full impredicative comprehension. Hume's Principle is one example of an abstraction principle, while another paradigmatic example is Basic Law V from Frege's ... More
On the Canonical Representatives of a Finite Weyl GroupMay 27 2015Apr 18 2016Let K be a field and G a split connected reductive affine algebraic K-group. Let T be a split maximal torus of G, W its finite Weyl group, and R its root system. After fixing a realization of R in G and choosing a simple system for R, one gets a system ... More
Squaring operations in the $RO(C_2)$-graded and real motivic Adams spectral sequencesFeb 15 2017Nov 16 2017In this paper we establish a formula for computing $d_2(sq^i(x))$ where $x$ is a permanent cycle in the $C_2$-equivariant Adams spectral sequence or the motivic Adams spectral sequence over $Spec(\mathbb{R})$. This requires establishing that the Adams ... More
X-rays from Superbubbles in the Large Magellanic Cloud IV: The Blowout Structure of N44Jun 13 1996We have used optical echelle spectra along with ROSAT and ASCA X-ray spectra to test the hypothesis that the southern portion of the N44 X-ray bright region is the result of a blowout structure. Three pieces of evidence now support this conclusion. First, ... More