Results for "Chris Schwiegelshohn"

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Fair Coresets and Streaming Algorithms for Fair k-Means ClusteringDec 28 2018Apr 27 2019We study fair clustering problems as proposed by Chierichetti et al. (NIPS 2017). Here, points have a sensitive attribute and all clusters in the solution are required to be balanced with respect to it (to counteract any form of data-inherent bias). Previous ... More
Maximizing Online Utilization with CommitmentApr 12 2019We investigate online scheduling with commitment for parallel identical machines. Our objective is to maximize the total processing time of accepted jobs. As soon as a job has been submitted, the commitment constraint forces us to decide immediately whether ... More
Sublinear Estimation of Weighted Matchings in Dynamic Data StreamsMay 08 2015Jul 09 2015This paper presents an algorithm for estimating the weight of a maximum weighted matching by augmenting any estimation routine for the size of an unweighted matching. The algorithm is implementable in any streaming model including dynamic graph streams. ... More
Random Projections for k-Means: Maintaining Coresets Beyond Merge & ReduceApr 07 2015Jul 09 2015We give a new construction for a small space summary satisfying the coreset guarantee of a data set with respect to the $k$-means objective function. The number of points required in an offline construction is in $\tilde{O}(k \epsilon^{-2}\min(d,k\epsilon^{-2}))$ ... More
Efficient Similarity Search in Dynamic Data StreamsMay 12 2016The Jaccard index is an important similarity measure for item sets and Boolean data. On large datasets, an exact similarity computation is often infeasible for all item pairs both due to time and space constraints, giving rise to faster approximate methods. ... More
Principal Fairness: \\ Removing Bias via ProjectionsMay 31 2019Reducing hidden bias in the data and ensuring fairness in algorithmic data analysis has recently received significant attention. We complement several recent papers in this line of research by introducing a general method to reduce bias in the data through ... More
Efficient Similarity Search in Dynamic Data StreamsMay 12 2016Oct 23 2017The Jaccard index is an important similarity measure for item sets and Boolean data. On large datasets, an exact similarity computation is often infeasible for all item pairs both due to time and space constraints, giving rise to faster approximate methods. ... More
Fair Coresets and Streaming Algorithms for Fair k-Means ClusteringDec 28 2018We study fair clustering problems as proposed by Chierichetti et al. Here, points have a sensitive attribute and all clusters in the solution are required to be balanced with respect to it (to counteract any form of data-inherent bias). Previous algorithms ... More
On Coresets for Logistic RegressionMay 22 2018Sep 13 2018Coresets are one of the central methods to facilitate the analysis of large data sets. We continue a recent line of research applying the theory of coresets to logistic regression. First, we show a negative result, namely, that no strongly sublinear sized ... More
Generic transversality for unbranched covers of closed pseudoholomorphic curvesJul 02 2014Dec 12 2014We prove that in closed almost complex manifolds of any dimension, generic perturbations of the almost complex structure suffice to achieve transversality for all unbranched multiple covers of simple pseudoholomorphic curves with deformation index zero. ... More
On the functor l^2Dec 21 2010Jul 29 2015We study the functor l^2 from the category of partial injections to the category of Hilbert spaces. The former category is finitely accessible, and in both categories homsets are algebraic domains. The functor preserves daggers, monoidal structures, enrichment, ... More
Complementarity in categorical quantum mechanicsSep 10 2010Mar 01 2016We relate notions of complementarity in three layers of quantum mechanics: (i) von Neumann algebras, (ii) Hilbert spaces, and (iii) orthomodular lattices. Taking a more general categorical perspective of which the above are instances, we consider dagger ... More
Evidence for a hard equation of state in the cores of neutron starsDec 19 2008The equation of state for matter with energy density above 2 x10^14 g/cm^3 is parametrized by P = kN^Gamma, where N is the number density, Gamma is the adiabatic index, and k a constant. Using this scheme to generate thousands of models, together with ... More
DIS and BeyondAug 30 2013A digest of my closing overview talk at DIS2013
Observational characteristics of accretion onto black holesAug 13 2010These notes resulted from a series of lectures at the IAC winter school. They are designed to help students, especially those just starting in subject, to get hold of the fundamental tools used to study accretion powered sources. As such, the references ... More
The origin of the soft excess in high L/L_Edd AGNMar 16 2007We discuss the origin of the soft X-ray excess seen in AGN. There are clear advantages to models where this arises from atomic processes in partially ionised material rather than where it is a true continuum component. However, current data cannot distinguish ... More
A short note on Simulation and AbstractionSep 20 2013This short note is written in celebration of David Schmidt's sixtieth birthday. He has now been active in the program analysis research community for over thirty years and we have enjoyed many interactions with him. His work on characterising simulations ... More
Implementation of classical communication in a quantum worldJun 19 2012Dec 18 2012Observations of quantum systems carried out by finite observers who subsequently communicate their results using classical data structures can be described as "local operations, classical communication" (LOCC) observations. The implementation of LOCC ... More
Consistent quantum mechanics admits no mereotopologyMay 13 2012Dec 09 2012It is standardly assumed in discussions of quantum theory that physical systems can be regarded as having well-defined Hilbert spaces. It is shown here that a Hilbert space can be consistently partitioned only if its components are assumed not to interact. ... More
If physics is an information science, what is an observer?Aug 24 2011Feb 11 2012Interpretations of quantum theory have traditionally assumed a "Galilean" observer, a bare "point of view" implemented physically by a quantum system. This paper investigates the consequences of replacing such an informationally-impoverished observer ... More
Autonomy all the way down: Systems and dynamics in quantum BayesianismAug 09 2011Apr 07 2012Quantum Bayesianism ("QBism") has been put forward as an approach to quantum theory that avoids foundational problems by altogether disavowing the objective existence of quantum states. It is shown that QBism suffers its own versions of the familiar foundational ... More
On the Ollivier-Poulin-Zurek definition of objectivityFeb 14 2011Jun 25 2013The Ollivier-Poulin-Zurek definition of objectivity provides a philosophical basis for the environment as witness formulation of decoherence theory and hence for quantum Darwinism. It is shown that no account of the reference of the key terms in this ... More
Information contents and architectural requirements of observer "ready" statesAug 09 2009Mar 05 2011A functional analysis of the task of observing multiple macroscopic quantum systems over an extended period of time and then reporting the accumulated results is used to investigate the information that must be encoded in the "ready" state |O^r> of any ... More
A sharp bilinear estimate for the Klein-Gordon equation in arbitrary space-time dimensionsFeb 21 2013We prove a sharp bilinear inequality for the Klein-Gordon equation on $\sr^{d+1}$, for any $d \geq 2$. This extends work of Ozawa-Rogers and Quilodr\'an for the Klein-Gordon equation and generalises work of Bez-Rogers for the wave equation. As a consequence ... More
Particle Physics: Themes and ChallengesNov 28 1995Opening Lecture at the Second Rencontres du Vietnam, October 21-28, 1995.
Ramification of Compatible Systems on Curves and Independence of $\ell$Jun 12 2014Oct 02 2014We show that certain ramification invariants associated to a compatible system of $\ell$-adic sheaves on a curve are independent of $\ell$.
Coupled one-dimensional dynamical systemsJan 19 2012This note aims to bring attention to a simple class of discrete dynamical systems exhibiting some complex behaviour. Each of these systems is defined as a self-mapping of the unit square and is obtained by coupling two families of self-mappings of the ... More
Some Notes on Standard Borel and Related SpacesSep 18 2008These notes give an elementary approach to parts of the theory of standard Borel and analytic spaces.
Quantum convolution and quantum correlation algorithms are physically impossibleSep 08 2003Dec 03 2003The key step in classical convolution and correlation algorithms, the componentwise multiplication of vectors after initial Fourier Transforms, is shown to be physically impossible to do on quantum states. Then this is used to show that computing the ... More
Periodic GraphsJun 12 2008Oct 15 2010Let $X$ be a graph on $n$ vertices with with adjacency matrix $A$ and let $H(t)$ denote the matrix-valued function $\exp(iAt)$. If $u$ and $v$ are distinct vertices in $X$, we say perfect state transfer}from $u$ to $v$ occurs if there is a time $\tau$ ... More
Locally Cartesian Closed Quasicategories from Type TheoryJul 09 2015We prove that the quasicategories arising from models of Martin-L\"of type theory via simplicial localization are locally cartesian closed.
Business Models for e-Health: Evidence from Ten Case StudiesJul 02 2015An increasingly aging population and spiraling healthcare costs have made the search for financially viable healthcare models an imperative of this century. The careful and creative application of information technology can play a significant role in ... More
Probing Light Dark Matter via Evaporation from the SunJun 13 2015Dark matter particles can be captured by the sun with rates that depend on the dark matter mass and the DM-nucleon cross section. However, for masses below $\sim 3.3$ GeV, the captured dark matter particles evaporate, leading to an equilibrium where the ... More
Recent Results from (Full) Lattice QCDMay 04 2000An overview of the Lattice technique for studies of the strong interaction is given. Recent results from the UKQCD lattice collaboration are presented. These concentrate on spectral quantities calculated using full (i.e. unquenched) QCD. A comparison ... More
Quantum Darwinism requires an extra-theoretical assumption of encoding redundancyMar 26 2010May 30 2010Observers restricted to the observation of pointer states of apparatus cannot conclusively demonstrate that the pointer of an apparatus A registers the state of a system of interest S without perturbing S. Observers cannot, therefore, conclusively demonstrate ... More
Decompositional equivalenceApr 12 2010Apr 21 2010Both classical and quantum mechanics assume that physical laws are invariant under changes in the way that the world is labeled. This Principle of Decompositional Equivalence is formalized, and shown to forbid finite experimental demonstrations that given ... More
Three consequences of decompositional consistencyJun 12 2009Decompositions of the world into systems have typically been regarded as arbitrary extra-theoretical assumptions in discussions of quantum measurement. One can instead regard decompositions as part of the theory, and ask what conditions they must satisfy ... More
A Brief Summary of the Group-Variation EquationsApr 29 2001A brief summary is given of the Group-Variation Equations and the island diagram confinement mechanism, with an explanation of the prediction that the cylinder-topology minimal-area spanning surface term in the correlation function of two Wilson loops ... More
Eigenvalues of the static, spherically-symmetric Einstein-Proca equationsSep 20 2016The Proca potential has been used in many contexts in flat spacetime, but not so often in curved spacetime. Here, the static Proca potentials are derived on a Schwarzschild background, and are found to have very different forms from those in flat space. ... More
Roulettes: A weak lensing formalism for strong lensing - I. OverviewMar 15 2016Jul 26 2016We present a new perspective on gravitational lensing. We describe a new extension of the weak lensing formalism capable of describing strongly lensed images. By integrating the non-linear geodesic deviation equation, the amplification matrix of weak ... More
Cosmological Perturbation Theory as a Tool for Estimating Box-Scale Effects in N-body SimulationsDec 17 2013Jun 16 2014In performing cosmological N-body simulations, it is widely appreciated that the growth of structure on the largest scales within a simulation box will be inhibited by the finite size of the simulation volume. Following ideas set forth in Seto (1999), ... More
Localised Solutions of the Maxwell-Dirac EquationsOct 11 1995The full ``classical" Dirac-Maxwell equations are considered under various simplifying assumptions. A reduction of the equations is performed in the case when the Dirac field is {\em static} and a further reduction is performed in the case of {\em spherical ... More
Glueballs, hybrid and exotic mesons and string breakingSep 11 2000We review lattice QCD results for glueballs (including a discussion of mixing with scalar mesons), hybrid mesons and exotic mesons (such as $B_s B_s$ molecules). We also discuss string breaking as a mixing between colour flux states and $B \bar{B}$ states. ... More
Hadronic decays from the latticeSep 06 2006I review the lattice QCD approach to determining hadronic decay transitions. Examples considered include rho to pi pi; b_1 to pi omega; hybrid meson decays and scalar meson decays. I discuss what lattices can provide to help understand the composition ... More
Smooth Volume Rigidity for Manifolds with Negatively Curved TargetsOct 04 2007We establish conditions for a continuous map of nonzero degree between a smooth closed manifold and a negatively curved manifold of dimension greater than four to be homotopic to a smooth cover, and in particular a diffeomorphism when the degree is one. ... More
Multi-scale Renormalisation Group Improvement of the Effective PotentialApr 14 1994Oct 12 1994Using the renormalisation group and a conjecture concerning the perturbation series for the effective potential, the leading logarithms in the effective potential are exactly summed for $O(N)$ scalar and Yukawa theories.
A new form of the Kerr solutionOct 27 1999Jan 31 2000A new form of the Kerr solution is presented. The solution involves a time coordinate which represents the local proper time for free-falling observers on a set of simple trajectories. Many physical phenomena are particularly clear when related to this ... More
Transversality and super-rigidity for multiply covered holomorphic curvesSep 30 2016Aug 14 2018We develop new techniques to study regularity questions for moduli spaces of pseudoholomorphic curves that are multiply covered. Among the main results, we show that unbranched multiple covers of closed holomorphic curves are generically regular, and ... More
Distinguishing Primitive Permutation GroupsJun 12 2008Nov 04 2009Let $G$ be a permutation group acting on a set $V$. A partition $\pi$ of $V$ is distinguishing if the only element of $G$ that fixes each cell of $\pi$ is the identity. The distinguishing number of $G$ is the minimum number of cells in a distinguishing ... More
On finite congruence-simple semiringsMay 08 2002Aug 19 2003In this paper, we describe finite, additively commutative, congruence simple semirings. The main result is that the only such semirings are those of order 2, zero-multiplication rings of prime order, matrix rings over finite fields, those that are additively ... More
A description of the Parry-Sullivan number of a graph using circuitsMar 11 2009In this short note, we give a description of the Parry-Sullivan number of a graph in terms of the cycles in the graph. This tool is occasionally useful in reasoning about the Parry-Sullivan numbers of graphs.
Reversible Markov chains: variational representations and orderingSep 06 2018This pedagogical document explains three variational representations that are useful when comparing the efficiencies of reversible Markov chains: (i) the Dirichlet form and the associated variational representations of the spectral gaps; (ii) a variational ... More
Crystal rules for $(\ell,0)$-JM partitionsJul 19 2011Vazirani and the author \cite{BV} gave a new interpretation of what we called $\ell$-partitions, also known as $(\ell,0)$-Carter partitions. The primary interpretation of such a partition $\lambda$ is that it corresponds to a Specht module $S^{\lambda}$ ... More
Lifting non-ordinary cohomology classes for SL(3)Feb 19 2016Jul 27 2017In this paper, we present a generalisation of a theorem of David and Rob Pollack. In 'A construction of rigid analytic cohomology classes for congruence subgroups of SL(3,Z)', they give a very general argument for lifting ordinary eigenclasses (with respect ... More
Colloquium: A Century of Noether's TheoremFeb 06 2019In the summer of 1918, Emmy Noether published the theorem that now bears her name, establishing a profound two-way connection between symmetries and conservation laws. The influence of this insight is pervasive in physics; it underlies all of our theories ... More
Simple, fast and accurate evaluation of the action of the exponential of a rate matrix on a probability vectorSep 19 2018Given a time-homogeneous, finite-statespace Markov chain with a rate matrix, or infinitesimal generator of $Q$, an initial distribution of $\nu$ and a time interval of $t$, the distribution across states at time $t$, $\nu^{\top} (t):=\nu^{\top}\exp (Q ... More
Power spectrum modelling of galaxy and radio intensity maps including observational effectsFeb 20 2019Fluctuations in the large-scale structure of the Universe contain significant information about cosmological physics, but are modulated in survey datasets by various observational effects. Building on existing literature, we provide a general treatment ... More
Decoherence as a sequence of entanglement swapsFeb 02 2019Standard semi-classical models of decoherence do not take explicit account of the classical information required to specify the system - environment boundary. I show that this information can be represented as a finite set of reference eigenvalues that ... More
Fast generalized DFTs for all finite groupsJan 08 2019For any finite group $G$, we give an arithmetic algorithm to compute generalized Discrete Fourier Transforms (DFTs) with respect to $G$, using $O(|G|^{\omega/2 + \epsilon})$ operations, for any $\epsilon > 0$. Here, $\omega$ is the exponent of matrix ... More
Locally Cartesian Closed Quasicategories from Type TheoryJul 09 2015Sep 17 2017We prove that the quasicategories arising from models of Martin-L\"of type theory via simplicial localization are locally cartesian closed.
C*-algebras from actions of congruence monoids on rings of algebraic integersJan 13 2019Let $K$ be a number field with ring of integers $R$. Given a modulus $\mathfrak{m}$ for $K$ and a group $\Gamma$ of residues modulo $\mathfrak{m}$, we consider the semi-direct product $R\rtimes R_{\mathfrak{m},\Gamma}$ obtained by restricting the multiplicative ... More
Identities for hyperelliptic P-functions of genus one, two and three in covariant formAug 22 2008We give a covariant treatment of the quadratic differential identities satisfied by the P-functions on the Jacobian of smooth hyperelliptic curves of genera 1, 2 and 3.
Lifestyle Tradeoffs and the Decline of Societal Well-being: An Agent-based ModelJul 20 2015Jan 01 2016This paper presents a semi-quantitative mathematical model of the changes over time in the statistical distribution of well-being of individuals in a society. The model predicts that when individuals overvalue the more socially conspicuous aspects of ... More
On the functor l^2Dec 21 2010Sep 18 2018We study the functor l^2 from the category of partial injections to the category of Hilbert spaces. The former category is finitely accessible, and its homsets are algebraic domains; the latter category has conditionally algebraic domains for homsets. ... More
Lectures on Symplectic Field TheoryDec 03 2016Dec 08 2016This is the preliminary manuscript of a book on symplectic field theory based on a lecture course for PhD students given in 2015-16. It covers the essentials of the analytical theory of punctured pseudoholomorphic curves, taking the opportunity to fill ... More
Rigidity of Spreadings and Fields of DefinitionApr 11 2017Varieties without deformations are defined over a number field. Several old and new examples of this phenomenon are discussed such as Bely\u \i\ curves and Shimura varieties. Rigidity is related to maximal Higgs fields which come from variations of Hodge ... More
Random planar graphs with bounds on the maximum and minimum degreesJan 27 2011Let P_{n,d,D} denote the graph taken uniformly at random from the set of all labelled planar graphs on {1,2,...,n} with minimum degree at least d(n) and maximum degree at most D(n). We use counting arguments to investigate the probability that P_{n,d,D} ... More
Generic transversality for unbranched covers of closed pseudoholomorphic curvesJul 02 2014Nov 03 2016We prove that in closed almost complex manifolds of any dimension, generic perturbations of the almost complex structure suffice to achieve transversality for all unbranched multiple covers of simple pseudoholomorphic curves with deformation index zero. ... More
Compactly accessible categories and quantum key distributionNov 13 2008Apr 19 2016Compact categories have lately seen renewed interest via applications to quantum physics. Being essentially finite-dimensional, they cannot accomodate (co)limit-based constructions. For example, they cannot capture protocols such as quantum key distribution, ... More
Accretion Flows in X--Ray Binaries and Active Galactic NucleiMay 29 2001Hard X-ray emission is ubiquitous in accreting black holes, both in Galactic binary systems and in Active Galactic Nuclei. I review the different spectra which can be seen from these systems, and possible ways of producing this emission. X-ray reflection ... More
On Modelling LifeMay 16 1994We present a theoretical as well as experimental investigation of a population of self-replicating segments of code subject to random mutation and survival of the fittest. Under the assumption that such a system constitutes a minimal system with characteristics ... More
The commuting graph of a soluble groupSep 11 2012The commuting graph of a finite soluble group with trivial centre is investigated. It is shown that the diameter of such a graph is at most 8 or the graph is disconnected. Examples of soluble groups with trivial centre and commuting graph of diameter ... More
The Development of Gas/Star Offsets in Tidal TailsNov 06 2000We present models of interacting galaxies in order to study the development of spatial offsets between the gaseous and stellar components in tidal tails. Observationally, such offsets are observed to exist over large scales (e.g., NGC 3690; Hibbard et ... More
Gas/Star Offsets in Tidal TailsAug 09 2000We use numerical simulations to study the development of gas/star offsets in the tidal tails of merging galaxies. These offsets are shown to be a natural consequence of the radially extended HI spatial distribution in disk galaxies, coupled with internal ... More
Morphology of Galaxy Mergers at Intermediate RedshiftOct 14 1994Using a combination of numerical simulation and synthesized Hubble Space Telescope Wide Field Camera 2 (HST WFC2) images, we follow the detectability of morphological signatures of disk galaxy mergers at intermediate redshifts z=0.4 and z=1.0. Rapid evolution ... More
Do mergers make (normal) ellipticals?Sep 06 2000Under the merger hypothesis, elliptical galaxies are built through mergers of gas-rich spirals. However, the relative paucity of HI in most normal ellipticals demands significant processing of atomic gas into other forms if this process is to be viable. ... More
Specifying Data Objects with Initial AlgebrasSep 19 2009This study presents a systematic approach to specifying data objects with the help of initial algebras. The primary aim is to describe the set-up to be found in modern functional programming languages such as Haskell and ML, although it can also be applied ... More
Investment Volatility: A Critique of Standard Beta Estimation and a Simple Way ForwardSep 20 2011Beta is a widely used quantity in investment analysis. We review the common interpretations that are applied to beta in finance and show that the standard method of estimation - least squares regression - is inconsistent with these interpretations. We ... More
A quantum Fourier transform algorithmApr 09 2004Jun 17 2004Algorithms to compute the quantum Fourier transform over a cyclic group are fundamental to many quantum algorithms. This paper describes such an algorithm and gives a proof of its correctness, tightening some claimed performance bounds given earlier. ... More
Computational costs of data definition at the quantum - classical interfaceMay 26 2010Model-independent semantic requirements for user specification and interpretation of data before and after quantum computations are characterized. Classical computational costs of assigning classical data values to quantum registers and to run-time parameters ... More
Generalized 1-skeleta and a lifting resultMar 17 2012Jul 01 2013In their paper "1-skeleta, Betti numbers, and equivariant cohomology" Guillemin and Zara described some beautiful constructions enabling them to use Morse theory on a certain class 1-skeleta including 1-skeleta of simple polytopes. In this paper we extend ... More
Dynamical Domain Wall FermionsOct 23 2003We report on an exploratory study of N_f=2 dynamical domain wall fermions and the DBW2 gauge action at weak coupling. Details of improved simulation algorithms and preliminary results for the hadron spectrum and renormalised light and strange quark masses ... More
Non-perturbative Renormalisation with Domain Wall FermionsNov 06 2000Nov 07 2000We present results from a study of the renormalisation of both quark bilinear and four-quark operators for the domain wall fermion action, using the non-perturbative renormalisation technique of the Rome-Southampton group. These results are from a quenched ... More
Light quark masses from Domain Wall FermionsOct 03 2002Oct 09 2002We present results for the renormalised light and strange quark masses calculated using Domain Wall Fermions in quenched QCD. New results using the DBW2 gauge action at inverse lattice spacings of approximately 2 GeV and 1.3 GeV will be presented and ... More
A new look at the isotropy of narrow line emission in extragalactic radio sourcesMar 03 1998We undertake a quantitative investigation, using Monte Carlo simulations, of the amount by which quasars are expected to exceed radio galaxies in optical luminosity in the context of the `receding torus' model. We compare these simulations with the known ... More
The luminosity dependence of the Type 1 AGN fractionMar 23 2005Using a complete, magnitude-limited sample of active galaxies from the Sloan Digital Sky Survey (SDSS) we show that the fraction of broad-line (Type 1) active galactic nuclei increases with luminosity of the isotropically-emitted [O III] narrow emission ... More
Earth's Stopping Effect in Directional Dark Matter DetectorsSep 29 2015We explore the stopping effect that results from interactions between dark matter and nuclei as the dark matter particles travel undergound towards the detector. Although this effect is negligible for heavy dark matter particles, there is parameter phase ... More
Some Notes on Finite SetsSep 09 2015Oct 05 2016These notes aim to give a gentle account to one approach to the theory of finite sets without making use of the natural numbers. They were written to be used as the basis for a student seminar. There are no real prerequisites except for a certain familiarity ... More
Accretion disc viscosity: a limit on the anisotropyApr 20 2015Observations of warped discs can give insight into the nature of angular momentum transport in accretion discs. Only a few objects are known to show strong periodicity on long timescales, but when such periodicity is present it is often attributed to ... More
An Ultradiscrete QRT mapping from Tropical Elliptic CurvesSep 22 2006Recently the area of tropical geometry has introduced the concept of the tropical elliptic group law associated with a tropical elliptic curve. This gives rise to a notion of the tropical QRT mapping. We compute the explicit tropically birational expressions ... More
Holonomy and Symmetry in M-theoryMay 05 2003May 07 2003Supersymmetric solutions of 11-dimensional supergravity can be classified according to the holonomy of the supercovariant derivative arising in the Killing spinor condition. It is shown that the holonomy must be contained in $\SL(32,\R)$. The holonomies ... More
Factored Latent Analysis for far-field tracking dataJul 11 2012This paper uses Factored Latent Analysis (FLA) to learn a factorized, segmental representation for observations of tracked objects over time. Factored Latent Analysis is latent class analysis in which the observation space is subdivided and each aspect ... More
Leptonic Decays of Heavy-Light SystemsSep 26 1995Oct 20 1995Results from recent lattice calculations of the decay constants $f_B$ and $f_D$ are reviewed. A discussion of the methods currently used is presented, together with an outline of the various systematic effects involved.
The Early Universe as a Probe of New PhysicsDec 24 2008The Standard Model of Particle Physics has been verified to unprecedented precision in the last few decades. However there are still phenomena in nature which cannot be explained, and as such new theories will be required. Since terrestrial experiments ... More
A Noisy-Influence Regularity Lemma for Boolean FunctionsOct 21 2016We present a regularity lemma for Boolean functions $f:\{-1,1\}^n \to \{-1,1\}$ based on noisy influence, a measure of how locally correlated $f$ is with each input bit. We provide an application of the regularity lemma to weaken the conditions on the ... More
Keeping It Real: Revisiting a Real-Space Approach to Running Ensembles of Cosmological N-body SimulationsJan 10 2012Apr 17 2013In setting up initial conditions for ensembles of cosmological N-body simulations there are, fundamentally, two choices: either maximizing the correspondence of the initial density field to the assumed fourier-space clustering or, instead, matching to ... More
Glueballs, hybrid and exotic mesonsJan 25 2001We review lattice QCD results for glueballs (including a discussion of mixing with scalar mesons), hybrid mesons and exotic mesons (such as $B_s B_s$ molecules).
Adiabatic surfaces from the lattice: excited gluonic potentialsSep 01 1998I describe the results from lattice studies of probing the vacuum with static colour sources. Topics include (i) Twang the flux tube: string models and hybrid mesons. (ii) Charge up the flux tube: adjoint and sextet sources. (iii) Several sources: how ... More
Electric-Magnetic Duality in Massless QED?Sep 08 2009Sep 09 2009The possibility that QED and recently developed non-Hermitian, or magnetic, versions of QED are equivalent is considered. Under this duality the Hamiltonians and anomalous axial currents of the two theories are identified. A consequence of such a duality ... More