Results for "Keira Brooks"

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Phase-Retrieval-Based Wavefront Metrology for High Contrast CoronagraphyMar 05 2019We discuss the use of parametric phase-diverse phase retrieval as an in-situ high-fidelity wavefront measurement method to characterize and optimize the transmitted wavefront of a high-contrast coronagraphic instrument. We apply our method to correct ... More
Polarization dOTF: on-sky focal plane wavefront sensingAug 16 2016The differential Optical Transfer Function (dOTF) is a focal plane wavefront sensing method that uses a diversity in the pupil plane to generate two different focal plane images. The difference of their Fourier transforms recovers the complex amplitude ... More
High-contrast Imager for Complex Aperture Telescopes (HiCAT): 6. Software Control Infrastructure and CalibrationMar 07 2019High contrast imaging using coronagraphy is one of the main avenues to enable the search for life on extrasolar Earth analogs. The HiCAT testbed aims to demonstrate coronagraphy and wavefront control for segmented on-axis space telescopes as envisioned ... More
High-contrast imager for complex aperture telescopes (HiCAT): 5. first results with segmented-aperture coronagraph and wavefront controlMar 13 2019Segmented telescopes are a possibility to enable large-aperture space telescopes for the direct imaging and spectroscopy of habitable worlds. However, the complexity of their aperture geometry, due to the central obstruction, support structures and segment ... More
Milky Way Tomography IV: Dissecting DustNov 21 2011We use SDSS photometry of 73 million stars to simultaneously obtain best-fit main-sequence stellar energy distribution (SED) and amount of dust extinction along the line of sight towards each star. Using a subsample of 23 million stars with 2MASS photometry, ... More
Moduli Space Cohomology and Wavefunctions in 3D Quantum GravitySep 23 1994Wavefunctionals of three dimensional quantum gravity are extracted from the 3D field theoretic analogs of the four dimensional Donaldson polynomials. Our procedure is generalizable to four and other dimensions. This is a summary of a talk presented at ... More
D-branes and Cosmological SingularitiesJul 25 2001Jul 27 2001The motion of a test Dq-brane in a Dp-brane background is studied. The induced metric on the test brane is then interpreted as the cosmology of the test brane universe. One is then able to resolve the resulting cosmological singularities. In particular, ... More
Diff(SIGMA) and Metrics from Hamiltonian-TQFT's in 2+1 DimensionsDec 23 1992The constraints of $BF$ topological gauge theories are used to construct Hamiltonians which are anti-commutators of the BRST and anti-BRST operators. Such Hamiltonians are a signature of Topological Quantum Field Theories (TQFT's). By construction, both ... More
The Physics Inside Topological Quantum Field TheoriesDec 01 1995We show that the equations of motion defined over a specific field space are realizable as operator conditions in the physical sector of a generalized Floer theory defined over that field space. The ghosts associated with such a construction are found ... More
Toward the Formation of Realistic Galaxy DisksMar 19 2010In this review I demonstrate that a realistic model for the formation of galaxy disks depends on a proper treatment of the gas in galaxies. Historically, cosmological simulations of disk galaxy formation have suffered from a lack of resolution and a physically ... More
Persistence Lenses: Segmentation, Simplification, Vectorization, Scale Space and Fractal Analysis of ImagesApr 25 2016Jun 21 2016A persistence lens is a hierarchy of disjoint upper and lower level sets of a continuous luminance image's Reeb graph. The boundary components of a persistence lens's interior components are Jordan curves that serve as a hierarchical segmentation of the ... More
The Variation of Rotation Curve Shapes as a Signature of the Effects of Baryons on Dark Matter Density ProfilesMay 31 2015Oct 16 2015Rotation curves of galaxies show a wide range of shapes, which can be paramaterized as scatter in Vrot(1kpc)/Vmax i.e.the ratio of the rotation velocity measured at 1kpc and the maximum measured rotation velocity. We examine whether the observed scatter ... More
Theory and Phenomenology of Dirac LeptogenesisDec 26 2007Dirac leptogenesis, in which neutrinos are purely Dirac and develop small but nonzero effective masses without the aid of the see-saw mechanism, provides an interesting alternative to the standard leptogenesis picture. Here we review the theory and phenomenology ... More
Requirements to Detect the Monoenergetic Photon Signature of Thermal Cold Dark Matter in PeV-Scale Split SupersymmetryMar 24 2005Split supersymmetry scenarios with PeV-scale scalar masses circumvent many of the restrictions on supersymmetry coming from experimental limits on CP violation, flavor-changing neutral currents, and the Higgs boson mass. We consider the situation where ... More
Re-Examining Astrophysical Constraints on the Dark Matter ModelJul 28 2014Recent high-resolution simulations that include Cold Dark Matter (CDM) and baryons have shown that baryonic physics can dramatically alter the dark matter structure of galaxies. These results modify our predictions for observed galaxy evolution and structure. ... More
Varilets: Additive Decomposition, Topological Total Variation, and Filtering of Scalar FieldsMar 16 2015Apr 26 2016Continuous interpolation of real-valued data is characterized by piecewise monotone functions on a compact metric space. Topological total variation of piecewise monotone function f:X->R is a homeomorphism-invariant generalization of 1D total variation. ... More
The Cosmological Constant and Volume-Preserving Diffeomorphism InvariantsOct 01 1993Nov 04 1993Observables in the quantum field theories of $(D-1)$-form fields, $\ca$, on $D$-dimensional, compact and orientable manifolds, $M$, are computed. Computations of the vacuum value of $T_{ab}$ find it to be the metric times a function of the volume of spacetime, ... More
Relating Scattering Amplitudes in Bosonic and Topological String TheoriesMar 11 1992A formal relationship between scattering amplitudes in critical bosonic string theory and correlation functions of operators in topological string theory is found.
Retinal Vessel Segmentation Using A New Topological MethodAug 03 2016A novel topological segmentation of retinal images represents blood vessels as connected regions in the continuous image plane, having shape-related analytic and geometric properties. This paper presents topological segmentation results from the DRIVE ... More
Cataclysmic Variables from SDSS. VIII. The Final Year (2007-2008)Sep 28 2011This paper completes the series of cataclysmic variables (CVs) identified from the Sloan Digital Sky Survey I/II. The coordinates, magnitudes and spectra of 33 CVs are presented. Among the 33 are eight systems known previous to SDSS (CT Ser, DO Leo, HK ... More
Hadronic Multi-Particle Final State Measurements with CLAS at Jefferson LabNov 04 2003Precision measurements in the neutrino sector are becoming increasingly feasible due to the development of relatively high-rate experimental capabilities. These important developments command renewed attention to the systematic corrections needed to interpret ... More
Space-Time Properties of Hadronization from Nuclear Deep Inelastic ScatteringOct 29 2003Hadronization, the process by which energetic quarks evolve into hadrons, has been studied phenomenologically for decades. However, little experimental insight has been gained into the space-time features of this fundamentally non-perturbative process. ... More
A matter of measurement: rotation velocities and the velocity function of dwarf galaxiesJun 01 2015The velocity function derived from large scale surveys can be compared with the predictions of LCDM cosmology, by matching the measured rotation velocities Vrot of galaxies to the maximum circular velocity of dark matter (DM) halos Vmax. For Vrot<50km/s, ... More
Quantum Gravity and Equivariant CohomologyJul 27 1994Aug 09 1994A procedure for obtaining correlation function densities and wavefunctionals for quantum gravity from the Donaldson polynomial invariants of topological quantum field theories, is given. We illustrate how our procedure may be applied to three and four ... More
Q-Exact Actions for BF TheoriesJan 04 1994The actions for all classical (and consequently quantum) $BF$ theories on $n$-manifolds is proven to be given by anti-commutators of hermitian, nilpotent, scalar fermionic charges with Grassmann-odd functionals. In order to show this, the space of fields ... More
Lepton Flavor Violation and Supersymmetric Dirac LeptogenesisJul 26 2006Aug 29 2006Dirac leptogenesis (or Dirac neutrinogenesis), in which neutrinos are purely Dirac particles, is an interesting alternative to the standard leptogenesis scenario. In its supersymmetric version, the modified form of the superpotential required for successful ... More
The Symmetry of MultiferroicsOct 09 2006Oct 12 2006This paper represents a detailed instruction manual for constructing the Landau expansion for magnetoelectric coupling in incommensurate ferroelectric magnets. The first step is to describe the magnetic ordering in terms of symmetry adapted coordinates ... More
Using Autoencoders To Learn Interesting Features For Detecting Surveillance AircraftSep 27 2018This paper explores using a Long short-term memory (LSTM) based sequence autoencoder to learn interesting features for detecting surveillance aircraft using ADS-B flight data. An aircraft periodically broadcasts ADS-B (Automatic Dependent Surveillance ... More
Non-negative Curvature and Conullity of the Curvature TensorMar 18 2019The conullity of a curvature tensor is the codimension of its kernel. We consider the cases of conullity two in any dimension and conullity three in dimension four. We show that these conditions are compatible with non-negative sectional curvature only ... More
J/Ψ and Ψ(2S) Production in p-Pb Collisions at 5.02 TeV with ATLASSep 22 2015The production rates of heavy quarkonia in ion-ion collisions provide sensitive probes in the studies of the hot and dense matter formed in these collisions at high energies. However, a reference for understanding the behavior in the hot medium is necessary; ... More
Jet quenching measurements with ATLAS at LHCNov 26 2010A broad program of measurements is planned for heavy ion collisions in ATLAS. With up to a factor of 30 increase in collision energy compared to existing data, significant new insights are anticipated to be obtained with the first data measured. Global ... More
Phenomenology of Dirac Neutrinogenesis in Split SupersymmetryNov 17 2005In Split Supersymmetry scenarios the possibility of having a very heavy gravitino opens the door to alleviate or completely solve the worrisome "gravitino problem'' in the context of supersymmetric baryogenesis models. Here we assume that the gravitino ... More
Recalculation of Proton Compton Scattering in Perturbative QCDApr 15 2000Oct 16 2000At very high energy and wide angles, Compton scattering on the proton (gamma p -> gamma p) is described by perturbative QCD. The perturbative QCD calculation has been performed several times previously, at leading twist and at leading order in alpha_s, ... More
Nongeometry, Duality Twists, and the WorldsheetNov 11 2005Jan 31 2006In this paper, we use orbifold methods to construct nongeometric backgrounds, and argue that they correspond to the spacetimes discussed in \cite{dh,wwf}. More precisely, we make explicit through several examples the connection between interpolating orbifolds ... More
The LHC Discovery Potential of a Leptophilic HiggsMar 04 2009In this work, we examine a two-Higgs-doublet extension of the Standard Model in which one Higgs doublet is responsible for giving mass to both up- and down-type quarks, while a separate doublet is responsible for giving mass to leptons. We examine both ... More
Bayesian Analysis of Loss Ratios Using the Reversible Jump AlgorithmJan 06 2011In this paper we consider the problem of model choice for a set of insurance loss ratios. We use a reversible jump algorithm for our model discrimination and show how the vanilla reversible jump algorithm can be improved on using recent methodological ... More
Properties of the diffuse emission around warm loops in solar active regionsJan 23 2019Coronal loops in active regions are the subjects of intensive investigation, but the important diffuse 'unresolved' emission in which they are embedded has received relatively little attention. Here we measure the densities and emission measure (EM) distributions ... More
Host-feeding enhances stability of discrete-time host-parasitoid population dynamic modelsMar 06 2015Discrete-time models are the traditional approach for capturing population dynamics of a host-parasitoid system. Recent work has introduced a semi-discrete framework for obtaining model update functions that connect host-parasitoid population levels from ... More
Non-localization of eigenfunctions on large regular graphsDec 16 2009We give a delocalization estimate for eigenfunctions of the discrete Laplacian on large $d+1$-regular graphs, showing that any subset of the graph supporting $\epsilon$ of the $L^2$ mass of an eigenfunction must be large. For graphs satisfying a mild ... More
Isoscattering on surfacesMay 21 2002We give a number of examples of pairs of non-compact surfaces which are isoscattering, and which are exceptionally simple in one or more senses. We give examples which are of small genus with a small number of ends, and also examles which are congruence ... More
Survey of Automated Vulnerability Detection and Exploit Generation Techniques in Cyber Reasoning SystemsFeb 20 2017Aug 07 2018Software is everywhere, from mission critical systems such as industrial power stations, pacemakers and even household appliances. This growing dependence on technology and the increasing complexity software has serious security implications as it means ... More
h-> mu^+ mu^- via tth Production at the LHCDec 09 2008In this work, we examine the process at the LHC in which a Higgs boson is produced in association with a t t-bar pair and subsequently decays to a pair of muons. We show that the statistical significance for the discovery of a light, Standard-Model Higgs ... More
Inference Networks for Sequential Monte Carlo in Graphical ModelsFeb 22 2016We introduce a new approach for amortizing inference in directed graphical models by learning heuristic approximations to stochastic inverses, designed specifically for use as proposal distributions in sequential Monte Carlo methods. We describe a procedure ... More
A Compilation Target for Probabilistic Programming LanguagesMar 03 2014Jul 10 2014Forward inference techniques such as sequential Monte Carlo and particle Markov chain Monte Carlo for probabilistic programming can be implemented in any programming language by creative use of standardized operating system functionality including processes, ... More
Graph Eigenfunctions and Quantum Unique ErgodicityJun 18 2010We apply the techniques of our previous paper to study joint eigenfunctions of the Laplacian and one Hecke operator on compact congruence surfaces, and joint eigenfunctions of the two partial Laplacians on compact quotients of $\mathbb{H}\times\mathbb{H}$. ... More
Open Access Publishing in Particle Physics: A Brief Introduction for the non-ExpertMay 23 2007Open Access to particle physics literature does not sound particularly new or exciting, since particle physicists have been reading preprints for decades, and arXiv.org for 15 years. However new movements in Europe are attempting to make the peer-reviewed ... More
Random Construction of Riemann SurfacesJun 28 2001In this paper, we address the following question: What does a typical compact Riemann surface of large genus look like geometrically? We do so by constructing compact Riemann surfaces from oriented 3-regular graphs. The set for such Riemann surfaces is ... More
Ferroelectricity Induced by Incommensurate MagnetismAug 30 2005Ferroelectricity has been found to occur in several insulating systems, such as TbMnO$_3$ (TMO) and Ni$_3$V$_2$O$_8$ (NVO) which have more than one phase with incommensurately modulated long-range magnetic order. Here we give a phenomenological model ... More
Distributed demand-side contingency-service provisioning while minimizing consumer disutility through local frequency measurements and inter-load communicationApr 15 2017Jun 29 2017We consider the problem of smart and flexible loads providing contingency reserves to the electric grid and provide a Distributed Gradient Projection (DGP) algorithm to minimize loads' disutility while providing contingency services. Each load uses locally ... More
NMR lineshape of $^{29}$Si in single-crystal siliconOct 11 2016We report measurements of the NMR lineshape of 4.685\% abundant $^{29}$Si in single-crystal silicon for four different crystallographic orientations relative to the applied magnetic field. To avoid significant inhomogeneous broadening, the sample crystals ... More
Isospectral But Physically Distinct: Modular Symmetries and their Implications for Carbon NanotoriMay 24 2010Aug 30 2011Recently there has been considerable interest in the properties of carbon nanotori. Such nanotori can be parametrized according to their radii, their chiralities, and the twists that occur upon joining opposite ends of the nanotubes from which they are ... More
Cascades and Collapses, Great Walls and Forbidden Cities: Infinite Towers of Metastable Vacua in Supersymmetric Field TheoriesNov 20 2008In this paper, we present a series of supersymmetric models exhibiting an entirely new vacuum structure: towers of metastable vacua with higher and higher energies. As the number of vacua grows towards infinity, the energy of the highest vacuum remains ... More
Quantum Dynamics of a Hydrogen Molecule Confined in a Cylindrical PotentialJan 23 2003We study the coupled rotation-vibration levels of a hydrogen molecule in a confining potential with cylindrical symmetry. We include the coupling between rotations and translations and show how this interaction is essential to obtain the correct degeneracies ... More
The Carina Nebula: A Laboratory for Feedback and Triggered Star FormationSep 29 2008The Carina Nebula (NGC 3372) is our richest nearby laboratory in which to study feedback through UV radiation and stellar winds from very massive stars during the formation of an OB association, at an early phase before SNe have disrupted the environment. ... More
Counting Automorphic Forms on Norm One ToriJun 16 2016Jan 22 2018We give an asymptotic formula for the number of automorphic forms on the non-split norm one torus $T$ associated with an imaginary quadratic extension of $\mathbb{Q}$, ordered by analytic conductor.
Summary of activities in the Working Group on QCD Cascades of the HERA Monte Carlo workshopAug 16 1999We summarize the activities in working group 10 concerned with QCD cascades, and find that although much work still needs to be done, much progress was made during this workshop in understanding the merits and deficiencies of different programs.
Joint Quasimodes, Positive Entropy, and Quantum Unique ErgodicityDec 22 2011We study joint quasimodes of the Laplacian and one Hecke operator on compact congruence surfaces, and give conditions on the orders of the quasimodes that guarantee positive entropy on almost every ergodic component of the corresponding semiclassical ... More
Fault-tolerant quantum computation with asymmetric Bacon-Shor codesNov 06 2012Feb 09 2013We develop a scheme for fault-tolerant quantum computation based on asymmetric Bacon-Shor codes, which works effectively against highly biased noise dominated by dephasing. We find the optimal Bacon-Shor block size as a function of the noise strength ... More
Physics with Nuclei at an Electron Ion ColliderJul 31 2010Lepto-nuclear colliders offer unique experimental opportunities to probe QCD in an extended medium. Of the many possibilities, three experiments are described here that are clearly feasible and of high scientific importance. First, a direct measurement ... More
The Monopole Equations in Topological Yang-MillsDec 22 1994We twist the monopole equations of Seiberg and Witten and show how these equations are realized in topological Yang-Mills theory. A Floer derivative and a Morse functional are found and are used to construct a unitary transformation between the usual ... More
Exploring Geometric Property Thresholds For Filtering Non-Text Regions In A Connected Component Based Text Detection ApplicationSep 11 2017Automated text detection is a difficult computer vision task. In order to accurately detect and identity text in an image or video, two major problems must be addressed. The primary problem is implementing a robust and reliable method for distinguishing ... More
Prepositional Phrase Attachment through a Backed-Off ModelJun 22 1995Recent work has considered corpus-based or statistical approaches to the problem of prepositional phrase attachment ambiguity. Typically, ambiguous verb phrases of the form {v np1 p np2} are resolved through a model which considers values of the four ... More
A diagnostic of coronal elemental behavior during the inverse FIP effect in solar flaresJul 12 2018The solar corona shows a distinctive pattern of elemental abundances that is different from that of the photosphere. Low first ionization potential (FIP) elements are enhanced by factors of several. A similar effect is seen in the atmospheres of some ... More
Some results on Bessel functionals for GSp(4)Dec 31 2014We prove that every irreducible, admissible representation of GSp(4,F), where F is a non-archimedean local field of characteristic zero, admits a Bessel functional, provided the representation is not one-dimensional. Given such a representation, we explicitly ... More
Phenomenological Constraints on Axion Models of Dynamical Dark MatterMar 08 2012In two recent papers (arXiv:1106.4546, arXiv:1107.0721), we introduced "dynamical dark matter" (DDM), a new framework for dark-matter physics in which the requirement of stability is replaced by a delicate balancing between lifetimes and cosmological ... More
Twisting of Siegel paramodular formsApr 17 2014Oct 04 2016Let $S_k(\Gamma^{\mathrm{para}}(N))$ be the space of Siegel paramodular forms of level $N$ and weight $k$. Let $p\nmid N$ and let $\chi$ be a nontrivial quadratic Dirichlet character mod $p$. Based on our previous work, we define a linear twisting map ... More
Twisting of paramodular vectorsJul 09 2013Let $F$ be a non-archimedean local field of characteristic zero, let $(\pi,V)$ be an irreducible, admissible representation of $\GSp(4,F)$ with trivial central character, and let $\chi$ be a quadratic character of $F^\times$ with conductor $c(\chi)>1$. ... More
Siegel modular forms of degree two attached to Hilbert modular formsJun 26 2010Let E/Q be a real quadratic field and pi_0 a cuspidal, irreducible, automorphic representation of GL(2,A_E) with trivial central character and infinity type (2,2n+2) for some non-negative integer n. We show that there exists a non-zero Siegel paramodular ... More
Multi-Level Spherical Locality Sensitive Hashing For Approximate Near NeighborsSep 11 2017Sep 15 2017This paper introduces "Multi-Level Spherical LSH": parameter-free, a multi-level, data-dependant Locality Sensitive Hashing data structure for solving the Approximate Near Neighbors Problem (ANN). This data structure uses a modified version of a multi-probe ... More
Learning to Synthesize Motion BlurNov 27 2018We present a technique for synthesizing a motion blurred image from a pair of unblurred images captured in succession. To build this system we motivate and design a differentiable "line prediction" layer to be used as part of a neural network architecture, ... More
Propagation of QCD Color through Strongly Interacting SystemsFeb 03 2019The propagation of QCD color through atomic nuclei is studied via a new analysis using a geometric model of semi-inclusive deep inelastic scattering. The experimental data were previously published by the HERMES Collaboration and consisted of the multiplicity ... More
Fourier coefficients for twists of Siegel paramodular forms (expanded version)May 20 2015In this paper, we calculate the Fourier coefficients of the paramodular twist of a Siegel modular form of paramodular level $N$ by a nontrivial quadratic Dirichlet character mod $p$ for $p$ a prime not dividing $N$. As an application, these formulas can ... More
Dynamical Dark Matter: I. Theoretical OverviewJun 22 2011Jun 04 2012In this paper, we propose a new framework for dark-matter physics. Rather than focus on one or more stable dark-matter particles, we instead consider a multi-component framework in which the dark matter of the universe comprises a vast ensemble of interacting ... More
Building a Nest at Tree Level: Classical Metastability and Non-Trivial Vacuum Structure in Supersymmetric Field TheoriesJun 20 2008Oct 15 2008It is becoming increasingly clear that metastable vacua may play a prominent role in supersymmetry-breaking. To date, however, this idea has been realized only in models where non-perturbative dynamics complicates the analysis of metastability. In this ... More
Counting Automorphic Forms on Norm One ToriJun 16 2016Oct 11 2016We give an asymptotic formula for the number of automorphic forms on the non-split torus $T$ associated with an imaginary quadratic extension of $\mathbb{Q}$, ordered by analytic conductor.
Gravitational Stability of Vortices in Bose-Einstein Condensate Dark MatterFeb 03 2009We investigate a simple model for a galactic halo under the assumption that it is dominated by a dark matter component in the form of a Bose-Einstein condensate involving an ultra-light scalar particle. In particular we discuss the possibility if the ... More
Appendix to "Twisting of Siegel paramodular forms"Apr 22 2014Oct 04 2016In this appendix we present an expanded version of Section 4 of our paper arXiv:1404.4596, including the proofs of all of the technical lemmas.
Stochastic Tools for Network Intrusion DetectionSep 22 2017With the rapid development of Internet and the sharp increase of network crime, network security has become very important and received a lot of attention. We model security issues as stochastic systems. This allows us to find weaknesses in existing security ... More
Why Baryons Matter: The Kinematics of Dwarf Spheroidal SatellitesJul 10 2012Apr 28 2014We use high resolution cosmological simulations of Milky Way-mass galaxies that include both baryons and dark matter to show that baryonic physics (energetic feedback from supernovae and subsequent tidal stripping) significantly reduces the dark matter ... More
Studies of Parton Propagation and Hadron Formation in the Space-Time DomainOct 07 2008Over the past decade, new data from HERMES, Jefferson Lab, Fermilab, and RHIC that connect to parton propagation and hadron formation have become available. Semi-inclusive DIS on nuclei, the Drell-Yan reaction, and heavy-ion collisions all bring different ... More
On the Inconsistency of Fayet-Iliopoulos Terms in Supergravity TheoriesNov 04 2009Dec 25 2009Motivated by recent discussions, we revisit the issue of whether globally supersymmetric theories with non-zero Fayet-Iliopoulos terms may be consistently coupled to supergravity. In particular, we examine claims that a fundamental inconsistency arises ... More
Medium Modifications of Hadron Properties and Partonic ProcessesApr 11 2011Apr 28 2011Chiral symmetry is one of the most fundamental symmetries in QCD. It is closely connected to hadron properties in the nuclear medium via the reduction of the quark condensate <bar{q}q>, manifesting the partial restoration of chiral symmetry. To better ... More
An Optimal Linear Time Algorithm for Quasi-Monotonic SegmentationFeb 24 2007Monotonicity is a simple yet significant qualitative characteristic. We consider the problem of segmenting an array in up to K segments. We want segments to be as monotonic as possible and to alternate signs. We propose a quality metric for this problem, ... More
The Formation of Galaxy DisksJan 11 2008Jan 14 2008We present a new set of multi-million particle SPH simulations of the formation of disk dominated galaxies in a cosmological context. Some of these galaxies are higher resolution versions of the models already described in Governato et al (2007). To correctly ... More
Dynamical Dark Matter and the Positron Excess in Light of AMSJun 12 2013Oct 28 2013The AMS-02 experiment has recently released data which confirms a rise in the cosmic-ray positron fraction as a function of energy up to approximately 350 GeV. Over the past decade, attempts to interpret this positron excess in terms of dark-matter decays ... More
A Tale of Two Timescales: Mixing, Mass Generation, and Phase Transitions in the Early UniverseSep 01 2015Light scalar fields such as axions and string moduli can play an important role in early-universe cosmology. However, many factors can significantly impact their late-time cosmological abundances. For example, in cases where the potentials for these fields ... More
Isoscattering Schottky ManifoldsMay 23 2000The authors exhibit pairs of infinite-volume, hyperbolic three-manifolds that have the same scattering poles and conformally equivalent boundaries, but which are not isometric. The examples are constructed using Schottky groups and the Sunada construction. ... More
Simultaneous identification of linear building dynamic model and disturbance using sparsity-promoting optimizationNov 17 2017Nov 20 2017We propose a method that simultaneously identifies a dynamic model of a building's temperature in the presence of large, unmeasured disturbances, and a transformed version of the unmeasured disturbance. Our method uses l1-regularization to encourage the ... More
A Decentralized Multi-block ADMM for Demand-side Primary Frequency Control using Local Frequency MeasurementsSep 28 2015We consider demand-side primary frequency control in the power grid provided by smart and flexible loads: loads change consumption to match generation and help the grid while minimizing disutility for consumers incurred by consumption changes. The dual ... More
Geometric Constructions of Nongeometric String TheoriesAug 26 2002Aug 18 2003We advocate a framework for constructing perturbative closed string compactifications which do not have large-radius limits. The idea is to augment the class of vacua which can be described as fibrations by enlarging the monodromy group around the singular ... More
Distinguishing Dynamical Dark Matter at the LHCApr 18 2012Dynamical dark matter (DDM) is a new framework for dark-matter physics in which the dark sector comprises an ensemble of individual component fields which collectively conspire to act in ways that transcend those normally associated with dark matter. ... More
The Temperature and Density Structure of the Solar Corona. I. Observations of the Quiet Sun with the EUV Imaging Spectrometer (EIS) on HinodeJan 12 2009Apr 30 2009Measurements of the temperature and density structure of the solar corona provide critical constraints on theories of coronal heating. Unfortunately, the complexity of the solar atmosphere, observational uncertainties, and the limitations of current atomic ... More
Experience Rating with Poisson MixturesDec 21 2010We present a mixture Poisson model for claims counts in which the number of components in the mixture are estimated by reversible jump MCMC methods.
Dynamical Dark Matter: II. An Explicit ModelJul 04 2011Jun 04 2012In a recent paper (arXiv:1106.4546), we introduced "dynamical dark matter," a new framework for dark-matter physics, and outlined its underlying theoretical principles and phenomenological possibilities. Unlike most traditional approaches to the dark-matter ... More
New Non-Trivial Vacuum Structures in Supersymmetric Field TheoriesDec 17 2008In this talk, we present three examples of new non-trivial vacuum structures that can occur in supersymmetric field theories, along with explicit models in which they arise. The first vacuum structure is one in which supersymmetry is broken at tree-level ... More
Experimental Studies of Hadronization and Parton Propagation in the Space-Time DomainJul 27 2009Sep 24 2009Over the past decade, new data have become available from DESY, Jefferson Lab, Fermilab, and RHIC that connect to parton propagation and hadron formation. Semi-inclusive DIS on nuclei, the Drell-Yan reaction, and heavy-ion collisions all bring different ... More
A Census of the Carina Nebula -- II. Energy Budget and Global Properties of the NebulosityMay 21 2007The first paper in this series took a direct census of energy input from the known OB stars in the Carina Nebula, and in this paper we study the global properties of the surrounding nebulosity. We find that the total IR luminosity of Carina is about 1.2E7 ... More
Twisting to Abelian BF/Chern-Simons TheoriesAug 26 1993Starting from a $D=3$, $N=4$ supersymmetric theory for matter fields, a twist with a Grassmann parity change is defined which maps the theory into a gauge fixed, abelian $BF$ theory on curved 3-manifolds. After adding surface terms to this theory, the ... More
Type Ia Supernovae and the Value of the Hubble ConstantNov 30 2000The methodology involved in deriving the Hubble Constant via the calibration of the corrected peak luminosities of Type Ia supernovae (SNe) is reviewed. We first present a re-analysis of the Calan-Tololo (C-T) and Center for Astrophysics (CfA) Type Ia ... More
Bulge Formation via Mergers in Cosmological SimulationsNov 12 2015The latest generation of cosmological simulations are on the verge of being able to resolve the structure of bulges for the first time. Hence, we review the current state of bulge formation in cosmological simulations, and discuss open questions that ... More