Results for "Sarah T. Stewart"

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The structure of terrestrial bodies: Impact heating, corotation limits and synestiasMay 22 2017During accretion, terrestrial bodies attain a wide range of thermal and rotational states, which are accompanied by significant changes in physical structure (size, shape, pressure and temperature profile, etc.). However, variations in structure have ... More
Collisional Stripping and Disruption of Super-EarthsJul 02 2009The final stage of planet formation is dominated by collisions between planetary embryos. The dynamics of this stage determine the orbital configuration and the mass and composition of planets in the system. In the solar system, late giant impacts have ... More
Water/Icy Super-Earths: Giant Impacts and Maximum Water ContentJul 19 2010Water-rich super-Earth exoplanets are expected to be common. We explore the effect of late giant impacts on the final bulk abundance of water in such planets. We present the results from smoothed particle hydrodynamics simulations of impacts between differentiated ... More
The Formation of the Collisional Family around the Dwarf Planet HaumeaMar 30 2010Haumea, a rapidly rotating elongated dwarf planet (~ 1500 km in diameter), has two satellites and is associated with a "family" of several smaller Kuiper Belt objects (KBOs) in similar orbits. All members of the Haumea system share a water ice spectral ... More
Minimum Radii of Super-Earths: Constraints from Giant ImpactsMar 01 2010The detailed interior structure models of super-Earth planets show that there is degeneracy in the possible bulk compositions of a super-Earth at a given mass and radius, determined via radial velocity and transit measurements, respectively. In addition, ... More
Tidal evolution of the Moon from a high-obliquity, high-angular-momentum EarthFeb 09 2018In the giant impact hypothesis for lunar origin, the Moon accreted from an equatorial circum-terrestrial disk; however the current lunar orbital inclination of 5 degrees requires a subsequent dynamical process that is still debated. In addition, the giant ... More
Compositional evolution during rocky protoplanet accretionSep 24 2015The Earth appears non-chondritic in its abundances of refractory lithophile elements, posing a significant problem for our understanding of its formation and evolution. It has been suggested that this non-chondritic composition may be explained by collisional ... More
Full Numerical Simulations of Catastrophic Small Body CollisionsNov 02 2008The outcome of collisions between small icy bodies, such as Kuiper belt objects, is poorly understood and yet a critical component of the evolution of the trans-Neptunian region. The expected physical properties of outer solar system materials (high porosity, ... More
Self-Assembly in the Growth of Precious OpalJan 04 2010It is proposed that primary nucleation of amorphous microspherulites of hydrated silica in natural proto-precious-opal can be followed by a long range superlattice ordering process by means of electrostatic self-assembly. Necessary conditions in the thermodynamics ... More
Collisions Between Gravity-Dominated Bodies: 1. Outcome Regimes and Scaling LawsJun 29 2011Jan 05 2012Collisions are the core agent of planet formation. In this work, we derive an analytic description of the dynamical outcome for any collision between gravity-dominated bodies. We conduct high-resolution simulations of collisions between planetesimals; ... More
Using photoemission spectroscopy to probe a strongly interacting Fermi gasApr 30 2008Ultracold atom gases provide model systems in which many-body quantum physics phenomena can be studied. Recent experiments on Fermi gases have realized a phase transition to a Fermi superfluid state with strong interparticle interactions. This system ... More
Direct observation of the Fermi surface in an ultracold atomic gasMar 30 2012The ideal (i.e. noninteracting), homogeneous Fermi gas, with its characteristic sharp Fermi surface in the momentum distribution, is a fundamental concept relevant to the behavior of many systems. With trapped Fermi gases of ultracold atoms, one can realize ... More
Verification of universal relations in a strongly interacting Fermi gasFeb 09 2010Many-body fermion systems are important in many branches of physics, including condensed matter, nuclear, and now cold atom physics. In many cases, the interactions between fermions can be approximated by a contact interaction. A recent theoretical advance ... More
Erosive Hit-and-Run Impact Events: Debris UnboundNov 16 2015Erosive collisions among planetary embryos in the inner solar system can lead to multiple remnant bodies, varied in mass, composition and residual velocity. Some of the smaller, unbound debris may become available to seed the main asteroid belt. The makeup ... More
SPH Simulations of Accretion Disks and Narrow RingsJul 12 1995We model a massless viscous disk using Smoothed Particle Hydrodynamics (SPH) and note that it evolves according to the Lynden-Bell \& Pringle theory (1974) until a non-axisymmetric instability develops at the inner edge of the disk. This instability may ... More
On the maximum grain size entrained by photoevaporative windsAug 29 2016We model the behaviour of dust grains entrained by photoevaporation-driven winds from protoplanetary discs assuming a non-rotating, plane-parallel disc. We obtain an analytic expression for the maximum entrainable grain size in extreme-UV radiation-driven ... More
2D condensation model for the inner Solar Nebula: an enstatite-rich environmentJan 07 2016Infrared observations provide the dust composition in the protoplanetary discs surface layers, but can not probe the dust chemistry in the midplane, where planet formation occurs. Meteorites show that dynamics was important in determining the dust distribution ... More
Growing dust grains in protoplanetary discs - III. Vertical settlingOct 09 2013Nov 06 2013We aim to derive a simple analytic model to understand the essential properties of vertically settling growing dust grains in laminar protoplanetary discs. Separating the vertical dynamics from the motion in the disc midplane, we integrate the equations ... More
Revisiting the "radial-drift barrier" of planet formation and its relevance in observed protoplanetary discsNov 14 2011Context. To form metre-sized pre-planetesimals in protoplanetary discs, growing grains have to decouple from the gas before they are accreted onto the central star during their phase of fast radial migration and thus overcome the so-called "radial-drift ... More
Insights into Quasar UV Spectra Using Unsupervised Clustering AnalysisMar 10 2016Machine learning can provide powerful tools to detect patterns in multi-dimensional parameter space. We use K-means -a simple yet powerful unsupervised clustering algorithm which picks out structure in unlabeled data- to study a sample of quasar UV spectra ... More
Improved Coincident and Coherent Detection Statistics for Searches for Gravitational Wave Ringdown SignalsOct 09 2013Oct 15 2013We study an improved method for detecting gravitational wave (GW) signals from perturbed black holes by earth-based detectors in the quest for searching for intermediate-mass black holes (IMBHs). Such signals, called ringdowns, are damped sinusoids whose ... More
Physical effects of collisions in the Kuiper beltMay 27 2007Collisions are a major modification process over the history of the Kuiper Belt. Recent work illuminates the complex array of possible outcomes of individual collisions onto porous, volatile bodies. The cumulative effects of such collisions on the surface ... More
Constraints on the Source of Lunar Cataclysm ImpactorsDec 10 2009Multiple impact basins formed on the Moon about 3.8 Gyr ago in what is known as the lunar cataclysm or late heavy bombardment. Many workers currently interpret the lunar cataclysm as an impact spike primarily caused by main-belt asteroids destabilized ... More
Erosive Hit-and-Run Impact Events: Debris UnboundNov 16 2015Oct 31 2016Erosive collisions among planetary embryos in the inner solar system can lead to multiple remnant bodies, varied in mass, composition and residual velocity. Some of the smaller, unbound debris may become available to seed the main asteroid belt. The makeup ... More
Lectures on the stable homotopy of BGOct 31 2007Mar 30 2009This paper is a survey of the stable homotopy theory of BG for G a finite group. It is based on a series of lectures given at the Summer School associated with the Topology Conference at the Vietnam National University, Hanoi, August 2004.
Algorithmic Diversity for Software SecurityDec 13 2013Software diversity protects against a modern-day exploits such as code-reuse attacks. When an attacker designs a code-reuse attack on an example executable, it relies on replicating the target environment. With software diversity, the attacker cannot ... More
An iterated search for influence from the future on the Large Hadron ColliderDec 05 2007Dec 15 2007We analyse an iterated version of Nielsen and Ninomiya (N&N)'s proposed card game experiment to search for a specific type of backward causation on the running of the Large Hadron Collider (LHC) at CERN. We distinguish "endogenous" and "exogenous" potential ... More
Gamma-rays Associated with Nearby Thunderstorms at Ground LevelAug 07 2014The TGF and Energetic Thunderstorm Rooftop Array (TETRA) is an array of NaI scintillators located at rooftop level on the campus of Louisiana State University in Baton Rouge, Louisiana. From July 2010 through March 2014, TETRA has detected 28 millisecond-duration ... More
The Threshold t-tbar Cross Section at NNLL OrderJul 13 2001The total cross section for top quark pair production close to threshold in e+e- annihilation is investigated. Details are given about the calculation at next-to-next-to-leading logarithmic order. The summation of logarithms leads to a convergent expansion ... More
Superconductivity in Undoped Single Crystals of BaFe2As2: Field and Current DependenceJul 25 2009In previous work in undoped MFe2As2, partial drops in the resistivity indicative of traces of superconductivity have been observed in some samples of M=Ba (Tc ~ 20 K, up to 25% drop in resistivity) and M=Ca (Tc ~ 10 K, up to 45 % drop in resistivity.) ... More
ASCA observations of deep ROSAT fields V. The X-ray spectrum of hard X-ray selected QSOsMay 08 2001We present an analysis of the \rosat and \asca spectra of 21 broad line AGN (QSOs) with $z\sim 1$ detected in the 2-10 keV band with the \asca \gis. The summed spectrum in the \asca band is well described by a power-law with $\Gamma=1.56\pm0.18$, flatter ... More
The discovery of a high redshift type 2 QSOSep 04 1995We report the discovery of a high redshift, narrow emission-line galaxy identified in the optical follow-up of deep ROSAT fields. The object has a redshift of z=2.35 and its narrow emission lines together with its high optical and X-ray luminosity imply ... More
p-wave Feshbach moleculesMar 03 2007May 01 2008We have produced and detected molecules using a p-wave Feshbach resonance between 40K atoms. We have measured the binding energy and lifetime for these molecules and we find that the binding energy scales approximately linearly with magnetic field near ... More
Thermal Inflation and the Gravitational Wave BackgroundJan 28 2008Apr 29 2008We consider the impact of thermal inflation -- a short, secondary period of inflation that can arise in supersymmetric scenarios -- on the stochastic gravitational wave background. We show that while the primordial inflationary gravitational wave background ... More
Jet Mass Spectra in Higgs + One Jet at NNLLFeb 04 2013Jul 29 2013The invariant mass of a jet is a benchmark variable describing the structure of jets at the LHC. We calculate the jet mass spectrum for Higgs plus one jet at the LHC at next-to-next-to-leading logarithmic (NNLL) order using a factorization formula. At ... More
Jet Regions from Event Shapes and the N-Jet Soft Function at Hadron CollidersSep 14 2011The N-jettiness event shape divides phase space into N+2 regions, each containing one jet or beam. These jet regions are insensitive to the distribution of soft radiation and, with a geometric measure for N-jettiness, have circular boundaries. We give ... More
ASCA observations of deep ROSAT fields I. the nature of the X-ray source populationsApr 15 1997We present ASCA GIS observations (total exposure 100-200 ksec) of three fields which form part of our deep ROSAT survey. We detect 26 sources down to a limiting flux (2-10 keV) of 5x10^{-14} erg cm-2 s-1. Sources down to this flux level contribute 30 ... More
ASCA observations of deep ROSAT fields IV.IR and hard X-ray observations of an obscured high-redshift QSOOct 26 1998We use UKIRT and ASCA observations to determine the nature of a high redshift (z=2.35) narrow-line AGN, previously discovered by Almaini et al. (1995). The UKIRT observations show a broad Halpha line while no Hbeta line is detected. This together with ... More
The Major and Minor Galaxy Merger Rates at z < 1.5Aug 11 2011Calculating the galaxy merger rate requires both a census of galaxies identified as merger candidates, and a cosmologically-averaged `observability' timescale T_obs(z) for identifying galaxy mergers. While many have counted galaxy mergers using a variety ... More
Predicting Dust Distribution in Protoplanetary DiscsOct 31 2003We present the results of three-dimensional numerical simulations that include the effects of hydrodynamical forces and gas drag upon an evolving dusty gas disk. We briefly describe a new parallel, two phase numerical code based upon the smoothed particle ... More
TETRA Observation of Gamma Rays at Ground Level Associated with Nearby ThunderstormsDec 19 2013Terrestrial Gamma ray Flashes (TGFs) -- very short, intense bursts of electrons, positrons, and energetic photons originating from terrestrial thunderstorms -- have been detected with satellite instruments. TETRA, an array of NaI(Tl) scintillators at ... More
Racah Polynomials and Recoupling Schemes of $\mathfrak{su}(1,1)$Apr 14 2015Jul 23 2015The connection between the recoupling scheme of four copies of $\mathfrak{su}(1,1)$, the generic superintegrable system on the 3 sphere, and bivariate Racah polynomials is identified. The Racah polynomials are presented as connection coefficients between ... More
An Explicit Construction of Type A Demazure AtomsJul 28 2007Apr 02 2009Demazure characters of type A, which are equivalent to key polynomials, have been decomposed by Lascoux and Sch\"{u}tzenberger into standard bases. We prove that the resulting polynomials, which we call Demazure atoms, can be obtained from a certain specialization ... More
A Collisional Origin to Earth's Non-chondritic Composition?Oct 13 2014Several lines of evidence indicate a non-chondritic composition for Bulk Earth. If Earth formed from the accretion of chondritic material, its non-chondritic composition, in particular the super-chondritic 142Nd/144Nd and low Mg/Fe ratios, might be explained ... More
Factorization, Effective Field Theory, and B-> D^(*) X DecaysSep 14 2002Nov 21 2002In this proceedings I review the soft-collinear effective theory (SCET), an effective theory for energetic particles. I also discuss factorization in exclusive and inclusive B-> D^(*)X decays, and tests which can help distinguish whether factorization ... More
Bound States in NRQCD/NRQED and the Renormalization GroupSep 15 2000The application of renormalization group techniques to bound states in non-relativistic QED and QCD is discussed. For QED bound states like Hydrogen and positronium, the renormalization group allows large logarithms of the velocity, ln v (or equivalently ... More
Applications of Chiral Perturbation Theory in Reactions with Heavy ParticlesJul 21 1999Effective field theory techniques are used to describe the interaction of heavy hadrons in a model independent way. Predictability is obtained by exploiting the symmetries of QCD. Heavy hadron chiral perturbation theory is reviewed and used to describe ... More
Maximum-likelihood detection of sources among Poissonian noiseJan 21 2009A maximum likelihood (ML) technique for detecting compact sources in images of the x-ray sky is examined. Such images, in the relatively low exposure regime accessible to present x-ray observatories, exhibit Poissonian noise at background flux levels. ... More
The Soft-Collinear Effective TheoryJul 20 2002In this talk I review an effective field theory that has been developed for processes with energetic hadrons, referred to as the Soft-Collinear Effective Theory. After outlining properties of the effective theory I briefly discuss its application to the ... More
Observational Constraints on Theories with a Blue Spectrum of Tensor ModesNov 28 2007Jul 13 2008Motivated by the string gas cosmological model, which predicts a blue tilt of the primordial gravitational wave spectrum, we examine the constraints imposed by current and planned observations on a blue tilted tensor spectrum. Starting from an expression ... More
Photon production from gluon mediated quark-anti-quark annihilation at confinementApr 07 2015Jun 20 2015Heavy ion collisions at RHIC produce direct photons at low transverse momentum, $p_{T}$ from 1-3 GeV/c, in excess of the $p$$+$$p$ spectra scaled by the nuclear overlap factor, $T_{AA}$. These low $p_{T}$ photons have a large azimuthal anisotropy, $v_{2}$. ... More
Exactness of free and amenable groups by the construction of Ozawa kernelsSep 15 2004Jun 01 2005Using properties of their Cayley graphs, specific examples of Ozawa kernels are constructed for both free and amenable groups, thus showing that these groups satisfy Property O. It is deduced both that these groups are exact and satisfy Yu's Property ... More
Landau Levels, Anisotropy and HolographyJun 13 2013We analyze properties of field theories dual to extremal black branes in (4+1) dimensions with anisotropic near-horizon geometries. Such gravity solutions were recently shown to fall into nine classes which align with the Bianchi classification of real ... More
On the polynomial Szemerédi's theorem in finite fieldsFeb 06 2018Let $P_1,\dots,P_m\in\mathbb{Z}[y]$ be any linearly independent polynomials with zero constant term. We show that there exists a $\gamma>0$ such that any subset of $\mathbb{F}_q$ of size at least $q^{1-\gamma}$ contains a nontrivial polynomial progression ... More
On the problem of non-zero word error rates for fixed rate error correction codes in continuous variable quantum key distributionMay 16 2016Oct 05 2016The maximum operation range of continuous variable quantum key distribution systems has shown to be improved by employing high efficiency forward error correction codes such as multi-edge low-density parity-check codes. In this paper, we show that the ... More
Patterning Superconductivity in a Topological InsulatorOct 27 2016While topological superconductors are predicted to provide building blocks for fault-tolerant quantum computing, one of the remaining challenges is to find a convenient experimental platform that would allow patterning of circuits. We find that superconductivity ... More
ALMA images of discs: are all gaps carved by planets?Sep 02 2015Protoplanetary discs are now routinely observed and exoplanets, after the numerous indirect discoveries, are starting to be directly imaged. To better understand the planet formation process, the next step is the detection of forming planets or of signposts ... More
Atom--Molecule Coherence in a Bose-Einstein CondensateApr 20 2002Apr 30 2002Coherent coupling between atoms and molecules in a Bose-Einstein condensate (BEC) has been observed. Oscillations between atomic and molecular states were excited by sudden changes in the magnetic field near a Feshbach resonance and persisted for many ... More
Oracle inequalities for the Lasso in the high-dimensional Aalen multiplicative intensity modelJun 25 2012Oct 14 2013In a general counting process setting, we consider the problem of obtaining a prognostic on the survival time adjusted on covariates in high-dimension. Towards this end, we construct an estimator of the whole conditional intensity. We estimate it by the ... More
Infinite-dimensional cohomology of SL_2(Z[t, 1/t])Jun 05 2015For J an integral domain and F its field of fractions, we construct a map from the 3-skeleton of the classifying space for {\Gamma} = SL_2(J[t,1/t]) to a Euclidean building on which {\Gamma} acts. We then find an infinite family of independent cocycles ... More
sPHENIX: The next generation heavy ion detector at RHICNov 09 2016sPHENIX is a new collaboration and future detector project at Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC). It seeks to answer fundamental questions on the nature of the quark gluon plasma (QGP), including its temperature dependence ... More
Periods on the moduli space of genus 0 curvesNov 13 2009This report outlines a combinatorial recipe for computing the bases, whose elements are oriented polygons, of two cohomology spaces associated to multizeta values: the top dimensional de Rham cohomology of moduli spaces of genus 0 complex pointed curves ... More
Varieties for modules of finite dimensional Hopf algebrasDec 02 2016We survey variety theory for modules of finite dimensional Hopf algebras, recalling some definitions and basic properties of support and rank varieties where they are known. We focus specifically on properties known for classes of examples such as finite ... More
Data-model comparison using FORWARD and CoMPNov 13 2015The FORWARD SolarSoft IDL package is a community resource for model-data comparison, with a particular emphasis on analyzing coronal magnetic fields. FORWARD allows the synthesis of coronal polarimetric signals at visible, infrared, and radio frequencies, ... More
On exponential sums over orbits in $\mathbb{F}_p^d$Jun 10 2016Aug 23 2016This paper proves a bound for exponential sums over orbits of vectors in $\mathbb{F}_p^d$ under subgroups of $\rm{GL}_d(\mathbb{F}_p)$. The main tool is a classification theorem for approximate groups due to Gill, Helfgott, Pyber, and Szab\'o.
Hidden Photons in beam dump experiments and in connection with Dark MatterDec 18 2012Hidden sectors with light extra U(1) gauge bosons, so-called hidden photons, recently received much interest as natural feature of beyond standard model scenarios like string theory and SUSY and because of their possible connection to dark matter. This ... More
The Asymptotics of Symbolic Generic Initial Systems of Six Points in P2Oct 31 2012Apr 30 2013Consider the ideal I in K[x,y,z] corresponding to six points of P2. We study the limiting behaviour of the symbolic generic initial system, of I obtained by taking the reverse lexicographic generic initial ideals of the symbolic powers of I. The main ... More
A 3-Local Characterization of the Harada--Norton Sporadic Simple GroupSep 25 2012We provide 3-local characterizations of the Harada--Norton sporadic simple group and its automorphism group. Both groups are examples of groups of parabolic characteristic three and we identify them from the structure of the normalizer of the centre of ... More
The Generic Initial Ideals of Powers of a 2-Complete IntersectionJun 25 2012Sep 30 2012We compute the reverse lexicographic generic initial ideals of the powers of a 2-complete intersection ideal I. In particular, we give six algorithms to compute these generic initial ideals, the choice of which depends on the power and on the relative ... More
A Decomposition of Schur functions and an analogue of the Robinson-Schensted-Knuth AlgorithmApr 19 2006Apr 02 2009We exhibit a weight-preserving bijection between semi-standard Young tableaux and semi-skyline augmented fillings to provide a combinatorial proof that the Schur functions decompose into nonsymmetric functions indexed by compositions. The insertion procedure ... More
Multizeta values: Lie algebras and periods on $\mathfrak{M}_{0,n}$Nov 13 2009This thesis is a study of algebraic and geometric relations between multizeta values. In chapter 2, we prove a result which gives the dimension of the associated depth-graded pieces of the double shuffle Lie algebra in depths 1 and 2. In chapters 3 and ... More
Hairdressing in groups: a survey of combings and formal languagesOct 29 1998A group is combable if it can be represented by a language of words satisfying a fellow traveller property; an automatic group has a synchronous combing which is a regular language. This article surveys results for combable groups, in particular in the ... More
Interatomic forces, phonons, the Foreman-Lomer Theorem and the Blackman Sum RuleNov 30 2011Foreman and Lomer proposed in 1957 a method of estimating the harmonic forces between parallel planes of atoms of primitive cubic crystals by Fourier transforming the squared frequencies of phonons propagating along principal directions. A generalized ... More
End-to-end people detection in crowded scenesJun 16 2015Jul 08 2015Current people detectors operate either by scanning an image in a sliding window fashion or by classifying a discrete set of proposals. We propose a model that is based on decoding an image into a set of people detections. Our system takes an image as ... More
Order alpha_s^2 beta_0 Correction to the Charged Lepton Spectrum in b \to c \ell \barν_\ell decaysSep 12 1996We compute the \alpha_s^2\beta_0 part of the two-loop QCD corrections to the charged lepton spectrum in b \to c \ell \bar\nu_\ell decays and find them to be about 50\% of the first order corrections at all lepton energies, except those close to the end ... More
Almost global existence for quasilinear wave equations in waveguides with Neumann boundary conditionsSep 14 2005In this paper, we prove almost global existence of solutions to certain quasilinear wave equations with quadratic nonlinearities in infinite homogeneous waveguides with Neumann boundary conditions. We use a Galerkin method to expand the Laplacian of the ... More
Gas Accretion and Angular MomentumDec 01 2016In this chapter, we review the role of gas accretion to the acquisition of angular momentum, both in galaxies and in their gaseous halos. We begin by discussing angular momentum in dark matter halos, with a brief review of tidal torque theory and the ... More
Edge Detection, Cosmic Strings and the South Pole TelescopeSep 04 2008Jan 07 2009We develop a method of constraining the cosmic string tension $G\mu$ which uses the Canny edge detection algorithm as a means of searching CMB temperature maps for the signature of the Kaiser-Stebbins effect. We test the potential of this method using ... More
On the center of the ring of differential operators on a smooth variety over $\bZ/p^n\bZ$Apr 14 2011We compute the center of the ring of PD differential operators on a smooth variety over $\bZ/p^n\bZ$ confirming a conjecture of Kaledin. More generally, given an associative algebra $A_0$ over $\bF_p$ and its flat deformation $A_n$ over $\bZ/p^{n+1}\bZ$ ... More
The cyclotomic BMW algebra associated with the two string type B braid groupNov 17 2006Oct 07 2010The cyclotomic Birman-Murakami-Wenzl (or BMW) algebras B_n^k, introduced by R. Haring-Oldenburg, are extensions of the cyclotomic Hecke algebras of Ariki-Koike, in the same way as the BMW algebras are extensions of the Hecke algebras of type A. In this ... More
Label-Free Supervision of Neural Networks with Physics and Domain KnowledgeSep 18 2016In many machine learning applications, labeled data is scarce and obtaining more labels is expensive. We introduce a new approach to supervising neural networks by specifying constraints that should hold over the output space, rather than direct examples ... More
Stasis Points and Approximating Two-CyclesApr 18 2005Generically, every fixed point for the differential inclusion x' in ConvexHull{f_1,f_2} can be approximated by an arbitrarily small two-cycle for the inclusion x' in {f_1,f_2}, where f_1, f_2 are a C^1 flows on R^n.
Program schemes with binary write-once arrays and the complexity classes they captureDec 03 2001We study a class of program schemes, NPSB, in which, aside from basic assignments, non-deterministic guessing and while loops, we have access to arrays; but where these arrays are binary write-once in that they are initialized to `zero' and can only ever ... More
On the Mathematics of Data Centre Network TopologiesMay 03 2016The theory of combinatorial designs has recently been used in order to build switch-centric data centre networks incorporating a large number of servers, in comparison with the popular Fat-Tree data centre network. The construction employed, called the ... More
The second cohomology of simple SL_2-modulesApr 03 2009Jul 27 2009Let $G$ be the simple algebraic group $SL_2$ defined over an algebraically closed field $K$ of characteristic $p>0$. In this paper, we find the second cohomology of all irreducible representations of $G$
The second cohomology of simple SL_3-modulesJul 27 2009Apr 10 2012Let G be the simple, simply connected algebraic group SL_3 defined over an algebraically closed field K of characteristic p>0. In this paper, we find H^2(G,V) for any irreducible G-module V. When p>7 we also find H^2(G(q),V) for any irreducible G(q)-module ... More
Extraction of the D^*Dπcoupling from D^* decaysMar 03 1998Jun 09 1998The decays D^* -> D\pi and D^* -> D\gamma are well described by heavy meson chiral perturbation theory. With the recent measurement of Br(D^{*+} -> D^+ \gamma), the D^{*0}, D^{*+}, and D_s^* branching fractions can be used to extract the D^*D\pi and D^*D\gamma ... More
On the freeness of the cyclotomic BMW algebras: admissibility and an isomorphism with the cyclotomic Kauffman tangle algebrasNov 27 2009The cyclotomic Birman-Murakami-Wenzl (BMW) algebras B_n^k, introduced by R. H\"aring-Oldenburg, are a generalisation of the BMW algebras associated with the cyclotomic Hecke algebras of type G(k,1,n) (aka Ariki-Koike algebras) and type B knot theory. ... More
A Multi-Wavelength Perspective of Flares on HR 1099: Four Years of Coordinated CampaignsFeb 25 2004We report on four years of multiple wavelength observations of the RS CVn system V711 Tau (HR 1099) from 1993, 1994, 1996, and 1998. This combination of radio, ultraviolet, extreme ultraviolet, and X-ray observations allows us to view, in the most comprehensive ... More
Pressure-induced superconductivity in the giant Rashba system BiTeIOct 25 2016At ambient pressure, BiTeI is the first material found to exhibit a giant Rashba splitting of the bulk electronic bands. At low pressures, BiTeI undergoes a transition from trivial insulator to topological insulator. At still higher pressures, two structural ... More
An XMM-Newton study of the sub-structure in M87's haloNov 20 2000The high signal to noise and good point spread function of XMM have allowed the first detailed study of the interaction between the thermal and radio emitting plasma in the central regions of M87. We show that the X-ray emitting structure, previously ... More
High Performance In Vivo Near-IR (>1 μm) Imaging and Photothermal Cancer Therapy with Carbon NanotubesNov 02 2010Short single-walled carbon nanotubes (SWNTs) functionalized by PEGylated phospholipids are biologically non-toxic and long-circulating nanomaterials with intrinsic near infrared photoluminescence (NIR PL), characteristic Raman spectra, and strong optical ... More
Stimulation-based control of dynamic brain networksJan 05 2016The ability to modulate brain states using targeted stimulation is increasingly being employed to treat neurological disorders and to enhance human performance. Despite the growing interest in brain stimulation as a form of neuromodulation, much remains ... More
The NGC4839 group falling into the Coma cluster observed by XMM-NewtonOct 21 2000We present here the first analysis of the XMM Newton EPIC-MOS data of the galaxy group around NGC4839, which lies at a projected distance to the Coma cluster center of 1.6Mpc. In our analysis, which includes imaging, spectro-imaging and spectroscopy we ... More
The Magnetic Structure of Paramagnetic MnOFeb 26 2016Using a combination of single-crystal neutron scattering and reverse Monte Carlo refinements, we study the magnetic structure of paramagnetic MnO at a temperature (160\,K) substantially below the Curie-Weiss temperature $|\theta|\sim550$\,K. The microscopic ... More
Theoretical formalism for collective electromagnetic response of discrete metamaterial systemsJun 01 2012Aug 08 2012We develop a general formalism to describe the propagation of a near-resonant electromagnetic field in a medium composed of magnetodielectric resonators. As the size and the spatial separation of nanofabricated resonators in a metamaterial array is frequently ... More
Shift-Symmetries at Higher OrderNov 09 2015Feb 09 2016The fate of shift-symmetries in effective string models is considered beyond tree-level. Such symmetries have been proposed in the past as a way to maintain a hierarchically small Higgs mass and also play a role in schemes of cosmological relaxation. ... More
The phase behaviour and structure of a fluid confined between competing (solvophobic and solvophilic) wallsJul 16 2012We consider a model fluid with long-ranged, dispersion interparticle potentials confined between competing parallel walls. One wall is solvophilic and would be completely wet at bulk liquid-gas coexistence while the other is solvophobic and would be completely ... More
Microresonator Isolators and Circulators Based on the Intrinsic Nonreciprocity of the Kerr EffectJan 30 2018Nonreciprocal light propagation is important in many applications, ranging from optical telecommunications to integrated photonics. A simple way to achieve optical nonreciprocity is to use the nonlinear interaction between counterpropagating light in ... More
Vibration Isolation Design for the Micro-X Rocket PayloadOct 13 2013Micro-X is a NASA-funded, sounding rocket-borne X-ray imaging spectrometer that will allow high precision measurements of velocity structure, ionization state and elemental composition of extended astrophysical systems. One of the biggest challenges in ... More