Results for "John Baker"

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Asymmetric L-space knotsOct 04 2017We construct the first examples of asymmetric L-space knots in $S^3$. More specifically, we exhibit a construction of hyperbolic knots in $S^3$ with both (i) a surgery that may be realized as a surgery on a strongly invertible link such that the result ... More
Rational linking and contact geometryJan 04 2009Apr 04 2014In the note we study Legendrian and transverse knots in rationally null-homologous knot types. In particular we generalize the standard definitions of self-linking number, Thurston-Bennequin invariant and rotation number. We then prove a version of Bennequin's ... More
Bridge number and integral Dehn surgeryMar 28 2013In a 3-manifold M, let K be a knot and R be an annulus which meets K transversely. We define the notion of the pair (R,K) being caught by a surface Q in the exterior of the link given by K and the boundary curves of R. For a caught pair (R,K), we consider ... More
Cabling, contact structures and mapping class monoidsMay 12 2010Aug 11 2011In this paper we discuss the change in contact structures as their supporting open book decompositions have their binding components cabled. To facilitate this and applications we define the notion of a rational open book decomposition that generalizes ... More
A New Approach to Quantum Gravity from a Model of an Elastic SolidOct 26 2008We show that the dynamics of an elastic solid embedded in a Minkowski space consist of a set of coupled equations describing a spin-1/2 field, $\Psi$, obeying Dirac's equation, a vector potential, $A_\mu$, obeying Maxwell's equations and a metric, $g_{\mu\nu}$, ... More
Gravitational-wave parameter estimation with gaps in LISA: a Bayesian data augmentation methodJul 10 2019By listening to gravity in the low frequency band, between 0.1 mHz and 1 Hz, the future space-based gravitational-wave observatory LISA will be able to detect tens of thousands of astrophysical sources from cosmic dawn to the present. The detection and ... More
A Derivation of Dirac's Equation From a Model of an Elastic MediumOct 21 2005Starting from a model of an elastic medium, we derive equations of motion that are identical in form to Dirac's equation for a spin 1/2 particle with mass, coupled to electromagnetic and gravitational interactions. The mass and electromagnetic terms are ... More
A Derivation of the Classical Einstein-Dirac-Maxwell Equations From a Model of an Elastic MediumNov 05 2006Starting from a model of an elastic medium, partial differential equations with the form of the coupled Einstein-Dirac-Maxwell equations are derived. The form of these equations describes particles with mass and spin coupled to electromagnetic and gravitational ... More
Prompt Electromagnetic Transients from Binary Black Hole MergersOct 05 2017Jan 16 2018Binary black hole (BBH) mergers provide a prime source for current and future interferometric GW observatories. Massive BBH mergers may often take place in plasma-rich environments, leading to the exciting possibility of a concurrent electromagnetic (EM) ... More
Coulomb Drag between One-Dimensional Wigner Crystal RingsJan 19 2001We consider the Coulomb drag between two metal rings in which the long range Coulomb interaction leads to the formation of a Wigner crystal. The first ring is threaded by an Ahranov Bohm flux creating a persistent current J_0. The second ring is brought ... More
The two-phase approximation for black hole collisions: Is it robust?Jan 15 1997Recently Abrahams and Cook devised a method of estimating the total radiated energy resulting from collisions of distant black holes by applying Newtonian evolution to the holes up to the point where a common apparent horizon forms around the two black ... More
A New Method for Solving the Initial Value Problem with Application to Multiple Black HolesFeb 03 1998This work consists of two distinct parts. In the first part we present a new method for solving the initial value problem of general relativity. Given any spatial metric with a surface orthogonal Killing field and two freely specified components of the ... More
How is spontaneous symmetry breaking possible?Mar 16 2011We pose and resolve a seeming paradox about spontaneous symmetry breaking in the quantum theory of infinite systems. For a symmetry to be spontaneously broken, it must not be implementable by a unitary operator. But Wigner's theorem guarantees that every ... More
Fourier-domain modulations and delays of gravitational-wave signalsJun 28 2018We present a Fourier-domain approach to modulations and delays of gravitational wave signals, a problem which arises in two different contexts. For space-based detectors like LISA, the orbital motion of the detector introduces a time-dependency in the ... More
Power operations and coactions in highly commutative homology theoriesSep 09 2013Dec 17 2014Power operations in the homology of infinite loop spaces, and $H_\infty$ or $E_\infty$ ring spectra have a long history in Algebraic Topology. In the case of ordinary mod p homology for a prime p, the power operations of Kudo, Araki, Dyer and Lashof interact ... More
Characteristics for $E_\infty$ ring spectraMay 14 2014Jun 01 2017We introduce a notion of characteristic for connective $p$-local $E_\infty$ ring spectra and study some basic properties. Apart from examples already pointed out by Markus Szymik, we investigate some examples built from Hopf invariant $1$ elements in ... More
Digit frequencies and self-affine sets with non-empty interiorJan 24 2017In this paper we study digit frequencies in the setting of expansions in non-integer bases, and self-affine sets with non-empty interior. Within expansions in non-integer bases we show that if $\beta\in(1,1.787\ldots)$ then every $x\in(0,\frac{1}{\beta-1})$ ... More
On universal and periodic $β$-expansions, and the Hausdorff dimension of the set of all expansionsDec 06 2012May 28 2013In this paper we study the topology of a set naturally arising from the study of $\beta$-expansions. After proving several elementary results for this set we study the case when our base is Pisot. In this case we give necessary and sufficient conditions ... More
Copulas from Order StatisticsDec 02 2014A new class of copulas based on order statistics was introduced by Baker (2008). Here, further properties of the bivariate and multivariate copulas are described, such as that of likelihood ratio dominance (LRD), and further bivariate copulas are introduced ... More
Properties and Applications of some Distributions derived from Frullani's integralAug 15 2014Frullani's integral dates from 1821, but a probabilistic interpretation of it has never been made. In this paper, Frullani's integral formula is shown to result from mixing a lifetime distribution by allowing the logarithm of the scale factor to be uniformly ... More
On the homology of regular quotientsMay 09 2013We construct a free resolution of $R/I^s$ over $R$ where $I\ideal R$ is generated by a (finite or infinite) regular sequence. This generalizes the Koszul complex for the case $s=1$. For $s>1$, we easily deduce that the algebra structure of $\Tor^R_*(R/I,R/I^s)$ ... More
Fractional parts of polynomials over the primes. IIApr 19 2017We consider the distance to the nearest integer of f(p), where f is a quadratic polynomial with irrational leading coefficient. This distance is very small as a function of p, for infinitely many primes p. We give a 14% improvement in the exponent that ... More
Power operations in $K$-theory completed at a primeJun 21 2014Aug 13 2018We describe the action of power operations on the $p$-completed cooperation algebras $K^\vee_0 K = K_0(K)\sphat_p$ for $K$-theory at a prime~$p$, and $K^\vee_0 KO = K_0(KO)\sphat_2$.
A proof of the parabolic Schauder estimates using Trudinger's method and the mean value property of the heat equationApr 04 2012One method available to prove the Schauder estimates is Neil Trudinger's method of mollification. In the case of second order elliptic equations, the method requires little more than mollification and the solid mean value inequality for subharmonic functions. ... More
Iterated doubles of the Joker and their realisabilityOct 09 2017Jul 03 2018Let $\mathcal{A}(1)^*$ be the subHopf algebra of the mod~$2$ Steenrod algebra $\mathcal{A}^*$ generated by $\mathrm{Sq}^1$ and $\mathrm{Sq}^2$. The \emph{Joker} is the cyclic $\mathcal{A}(1)^*$-module $\mathcal{A}(1)^*/\mathcal{A}(1)^*\{\mathrm{Sq}^3\}$ ... More
$\mathcal{E}_\infty$ ring spectra and elements of Hopf invariant $1$Mar 19 2015Apr 16 2017The $2$-primary Hopf invariant $1$ elements in the stable homotopy groups of spheres form the most accessible family of elements. In this paper we explore some properties of the $\mathcal{E}_\infty$ ring spectra obtained from certain iterated mapping ... More
Herschel and ALMA Observations of Massive SZE-selected ClustersDec 12 2017Jan 02 2018We present new Herschel observations of four massive, Sunyaev-Zel'dovich Effect (SZE)-selected clusters at $0.3 \leq z \leq 1.1$, two of which have also been observed with ALMA. We detect 19 Herschel/PACS counterparts to spectroscopically confirmed cluster ... More
An analogue of Khintchine's theorem for self-conformal setsSep 15 2016Khintchine's theorem is a classical result from metric number theory which relates the Lebesgue measure of certain limsup sets with the convergence/divergence of naturally occurring volume sums. In this paper we ask whether an analogous result holds for ... More
Badly approximable numbers for sequences of ballsMay 22 2014May 29 2014It is a classical result from Diophantine approximation that the set of badly approximable numbers has Lebesgue measure zero. In this paper we generalise this result to more general sequences of balls. Given a countable set of closed $d$-dimensional Euclidean ... More
On the cardinality and complexity of the set of codings for self-similar sets with positive Lebesgue measureFeb 28 2014May 28 2014Let $\lambda_{1},\ldots,\lambda_{n}$ be real numbers in $(0,1)$ and $p_{1},\ldots,p_{n}$ be points in $\mathbb{R}^{d}$. Consider the collection of maps $f_{j}:\mathbb{R}^{d}\to\mathbb{R}^{d} $ given by $$f_{j}(x)=\lambda_{j} x +(1-\lambda_{j})p_{j}.$$ ... More
Obtaining genus 2 Heegaard splittings from Dehn surgeryApr 30 2012Let K' be a hyperbolic knot in S^3 and suppose that some Dehn surgery on K' with distance at least 3 from the meridian yields a 3-manifold M of Heegaard genus 2. We show that if M does not contain an embedded Dyck's surface (the closed non-orientable ... More
A model study of corona emission from hydrometeorsMar 23 1998The maximum measured electric fields in thunderclouds are an order of magnitude less than the fields required for electric breakdown of the air. One explanation for lightning initiation in these low fields is that electric breakdown first occurs at the ... More
Effect of disorder on the non-dissipative dragJan 29 1999In this paper we consider the effect of disorder on the non-dissipative Coulomb drag between two mesoscopic metal rings at zero temperature. Ring 1 has an Aharonov-Bohm flux present which creates a persistent current J_0. Ring 2 interacts with ring 1 ... More
The Automatic Galaxy Collision SoftwareAug 24 2009The key to understanding the physical processes that occur during galaxy interactions is dynamical modeling, and especially the detailed matching of numerical models to specific systems. To make modeling interacting galaxies more efficient, we have constructed ... More
Decoding mode-mixing in black-hole merger ringdownDec 21 2012Apr 05 2013Optimal extraction of information from gravitational-wave observations of binary black-hole coalescences requires detailed knowledge of the waveforms. Current approaches for representing waveform information are based on spin-weighted spherical harmonic ... More
Fast singular value decay for Lyapunov solutions with nonnormal coefficientsOct 31 2014Jan 30 2015Lyapunov equations with low-rank right-hand sides often have solutions whose singular values decay rapidly, enabling iterative methods that produce low-rank approximate solutions. All previously known bounds on this decay involve quantities that depend ... More
Reducing reflections from mesh refinement interfaces in numerical relativityMay 19 2005Full interpretation of data from gravitational wave observations will require accurate numerical simulations of source systems, particularly binary black hole mergers. A leading approach to improving accuracy in numerical relativity simulations of black ... More
Bridge number, Heegaard genus and non-integral Dehn surgeryFeb 01 2012Nov 19 2013We show there exists a linear function w: N->N with the following property. Let K be a hyperbolic knot in a hyperbolic 3-manifold M admitting a non-longitudinal S^3 surgery. If K is put into thin position with respect to a strongly irreducible, genus ... More
Comparison of Atom Interferometers and Light Interferometers as Space-Based Gravitational Wave DetectorsJan 26 2012We consider a class of proposed gravitational wave detectors based on multiple atomic interferometers separated by large baselines and referenced by common laser systems. We compute the sensitivity limits of these detectors due to intrinsic phase noise ... More
The realizability of some finite-length modules over the Steenrod algebra by spacesMar 25 2019The Joker is a finite cyclic module over the mod-$2$ Steenrod algebra $\mathcal A$ which appears frequently in Adams resolutions as well as in Picard groups. In a previous paper, the first author commenced a study of when the Joker and its iterated Steenrod ... More
Erdős-Surányi sequences and trigonometric integralsJun 15 2015We study representations of integers as sums of the form $\pm a_1\pm a_2\pm \dotsb \pm a_n$, where $a_1,a_2,\ldots$ is a prescribed sequence of integers. Such a sequence is called an Erd\H{o}s-Sur\'anyi sequence if every integer can be written in this ... More
Degeneration of Linear Series From the Tropical Point of View and ApplicationsApr 21 2015Sep 07 2015In this survey, we discuss linear series on tropical curves and their relation to classical algebraic geometry, describe the main techniques of the subject, and survey some of the recent major developments in the field, with an emphasis on applications ... More
Some properties of Lubin-Tate cohomology for classifying spaces of finite groupsMay 10 2010May 31 2011We consider brave new cochain extensions $F(BG_+,R)\to F(EG_+,R)$, where $R$ is either a Lubin-Tate spectrum $E_n$ or the related 2-periodic Morava K-theory $K_n$, and $G$ is a finite group. When $R$ is an Eilenberg-Mac Lane spectrum, in some good cases ... More
A Cabling Conjecture for Knots in Lens SpacesJun 03 2013Closed 3-string braids admit many bandings to two-bridge links. By way of the Montesinos Trick, this allows us to construct infinite families of knots in the connected sum of lens spaces L(r,1) # L(s,1) that admit a surgery to a lens space for all pairs ... More
A Note on Sparsification by FramesAug 23 2013Dec 19 2014The purpose of this note is to establish a new generalized Dictionary-Restricted Isometry Property (D-RIP) sparsity bound constant for compressed sensing. For fulfilling D-RIP, the constant $\delta_k$ is used in the definition: $(1 -\delta_k)\|D v\|_2^2 ... More
A note on the concordance of fibered knotsSep 26 2014Jun 17 2015Either fibered knots supporting the tight contact structure are unique in their smooth concordance class or there exists a fibered counterexample to the Slice-Ribbon Conjecture.
On the complexity of the set of codings for self-similar sets and a variation on the construction of ChampernowneOct 16 2018Let $F=\{\mathbf{p}_0,\ldots,\mathbf{p}_n\}$ be a collection of points in $\mathbb{R}^d.$ The set $F$ naturally gives rise to a family of iterated function systems consisting of contractions of the form $$S_i(\mathbf{x})=\lambda \mathbf{x} +(1-\lambda)\mathbf{p}_i,$$ ... More
$Γ$-cohomology of rings of numerical polynomials and $E_\infty$ structures on K-theoryApr 29 2003Apr 25 2005We investigate Gamma-cohomology of some commutative cooperation algebras E_*E associated with certain periodic cohomology theories. For KU and E(1), the Adams summand at a prime p, and for KO we show that Gamma-cohomology vanishes above degree 1. As these ... More
Topological Hochschild cohomology and generalized Morita equivalenceAug 31 2002Sep 06 2004We explore two constructions in homotopy category with algebraic precursors in the theory of noncommutative rings and homological algebra, namely the Hochschild cohomology of ring spectra and Morita theory. The present paper provides an extension of the ... More
An infinitely generated self-similar set with positive Lebesgue measure and empty interiorJun 02 2018Mar 13 2019Peres and Solomyak asked the question: Do there exist self-similar sets with positive Lebesgue measure and empty interior? This question was answered in the affirmative by Cs\"{o}rnyei et al. They gave a parameterised family of iterated function systems ... More
The skeleton of the Jacobian, the Jacobian of the skeleton, and lifting meromorphic functions from tropical to algebraic curvesAug 18 2013Let K be an algebraically closed field which is complete with respect to a nontrivial, non-Archimedean valuation and let \Lambda be its value group. Given a smooth, proper, connected K-curve X and a skeleton \Gamma of the Berkovich analytification X^\an, ... More
Comparisons of binary black hole merger waveformsJan 01 2007Jun 05 2007This a particularly exciting time for gravitational wave physics. Ground-based gravitational wave detectors are now operating at a sensitivity such that gravitational radiation may soon be directly detected, and recently several groups have independently ... More
Improved Time-Domain Accuracy Standards for Model Gravitational WaveformsAug 10 2010Model gravitational waveforms must be accurate enough to be useful for detection of signals and measurement of their parameters, so appropriate accuracy standards are needed. Yet these standards should not be unnecessarily restrictive, making them impractical ... More
Observing mergers of non-spinning black-hole binariesApr 06 2010Advances in the field of numerical relativity now make it possible to calculate the final, most powerful merger phase of binary black-hole coalescence for generic binaries. The state of the art has advanced well beyond the equal-mass case into the unequal-mass ... More
Boundary-reducing surgeries and bridge numberDec 31 2015Let $M$ be a $3$--dimensional handlebody of genus $g$. This paper gives examples of hyperbolic knots in $M$ with arbitrarily large genus $g$ bridge number which admit Dehn surgeries which are boundary-reducible manifolds.
A slightly less grand challenge: Colliding Black Holes using perturbation techniquesOct 02 1997Perturbation techniques can be used as an alternative to supercomputer calculations in calculating gravitational radiation emitted by colliding black holes, provided the process starts with the black holes close to each other. We give a summary of the ... More
Finite-volume Hyperbolic 3-Manifolds contain immersed Quasi-Fuchsian surfacesAug 20 2014Apr 08 2015The paper contains a new proof that a complete, non-compact hyperbolic $3$-manifold $M$ with finite volume contains an immersed, closed, quasi-Fuchsian surface.
Twist families of L-space knots, their genera, and Seifert surgeriesJun 15 2015Apr 28 2017Conjecturally, there are only finitely many Heegaard Floer L-space knots in $S^3$ of a given genus. We examine this conjecture for twist families of knots $\{K_n\}$ obtained by twisting a knot $K$ in $S^3$ along an unknot $c$ in terms of the linking number ... More
Tight fibered knots and band sumsSep 01 2015We give a short proof that if a non-trivial band sum of two knots results in a tight fibered knot, then the band sum is a connected sum. In particular, this means that any prime knot obtained by a non-trivial band sum is not tight fibered. Since a positive ... More
The Classification of Rational Subtangle Replacements between Rational TanglesApr 24 2013A natural generalization of a crossing change is a rational subtangle replacement (RSR). We characterize the fundamental situation of the rational tangles obtained from a given rational tangle via RSR, building on work of Berge and Gabai, and determine ... More
Surfaces of Co-dimension Two Pinched by Normal CurvatureMay 20 2016We prove that codimension two surfaces satisfying a nonlinear curvature condition depending on normal curvature are smoothly deformed by mean curvature flow to round points.
Seifert vs slice genera of knots in twist families and a characterization of braid axesMay 29 2017Twisting a knot $K$ in $S^3$ along a disjoint unknot $c$ produces a twist family of knots $\{K_n\}$ indexed by the integers. Comparing the behaviors of the Seifert genus $g(K_n)$ and the slice genus $g_4(K_n)$ under twistings, we prove that if $g(K_n) ... More
Bijective proofs of shuffle compatibility resultsJun 17 2019Define a permutation to be any sequence of distinct positive integers. Given two permutations p and s on disjoint underlying sets, we denote by p sh s the set of shuffles of p and s (the set of all permutations obtained by interleaving the two permutations). ... More
Inhomogeneous self-similar sets with overlapsSep 11 2015It is known that if the underlying iterated function system satisfies the open set condition, then the upper box dimension of an inhomogeneous self-similar set is the maximum of the upper box dimensions of the homogeneous counterpart and the condensation ... More
Scope of Tunnel Junction Based Molecular Electronics and Spintronics DevicesJul 06 2014Scope of molecule based devices may govern the advancement of the next generation logic and memory devices. Molecules have the potential to be unmatched device elements as chemists can mass produce an endless variety of molecules with novel optical, magnetic, ... More
Optimal Physical MultipolesDec 14 2011Point multipole expansions are widely used to gain physical insight into complex distributions of charges and to reduce the cost of computing interactions between such distributions. However, practical applications that typically retain only a few leading ... More
Addressing the Challenges of Using Ferromagnetic Electrodes in the Molecular Spintronics DevicesJul 18 2015Ferromagnetic electrodes chemically bonded with thiol functionalized molecules can produce novel molecular spintronics devices. However, major challenges lie in developing Ferromagnetic electrodes based commercially viable device fabrication scheme that ... More
Robert F. Coleman 1954-2014Nov 13 2014Jan 18 2015Robert F. Coleman, a highly original mathematician who has had a profound influence on modern number theory and arithmetic geometry, passed away on March 24, 2014. We give an overview of his life and career, including some of his major contributions to ... More
Low energy properties of the random displacement modelAug 05 2008We study low-energy properties of the random displacement model, a random Schr\"odinger operator describing an electron in a randomly deformed lattice. All periodic displacement configurations which minimize the bottom of the spectrum are characterized. ... More
Minimizing the ground state energy of an electron in a randomly deformed latticeJul 26 2007We provide a characterization of the spectral minimum for a random Schr\"odinger operator of the form $H=-\Delta + \sum_{i \in \Z^d}q(x-i-\omega_i)$ in $L^2(\R^d)$, where the single site potential $q$ is reflection symmetric, compactly supported in the ... More
The Poincare homology sphere, lens space surgeries, and some knots with tunnel number twoApr 25 2015Dec 30 2015We exhibit an infinite family of knots in the Poincare homology sphere with tunnel number 2 that have a lens space surgery. Notably, these knots are not doubly primitive and provide counterexamples to a few conjectures. In the appendix, it is shown that ... More
The Strong Slope Conjecture for twisted generalized Whitehead doublesNov 28 2018The Slope Conjecture proposed by Garoufalidis asserts that the degree of the colored Jones polynomial determines a boundary slope, and its refinement, the Strong Slope Conjecture proposed by Kalfagianni and Tran asserts that the linear term in the degree ... More
The strong slope conjecture for graph knotsSep 04 2018We prove the Strong Slope Conjecture for graph knots. Along the way we propose some variants of the Strong Slope Conjecture and discuss their inheritance under cablings and connected sums.
X-ray Transients in the Advanced LIGO/Virgo HorizonMay 25 2013Jul 12 2013Advanced LIGO and Advanced Virgo will be all-sky monitors for merging compact objects within a few hundred Mpc. Finding the electromagnetic counterparts to these events will require an understanding of the transient sky at low red-shift (z<0.1). We performed ... More
How to move a black hole without excision: gauge conditions for the numerical evolution of a moving punctureMay 05 2006Jun 18 2006Recent demonstrations of unexcised black holes traversing across computational grids represent a significant advance in numerical relativity. Stable and accurate simulations of multiple orbits, and their radiated waves, result. This capability is critically ... More
A General Formula for Black Hole Gravitational Wave KicksMar 19 2010Although the gravitational wave kick velocity in the orbital plane of coalescing black holes has been understood for some time, apparently conflicting formulae have been proposed for the dominant out-of-plane kick, each a good fit to different data sets. ... More
General Relativistic Simulations of Magnetized Plasmas around Merging Supermassive Black HolesMar 27 2012May 15 2012Coalescing supermassive black hole binaries are produced by the mergers of galaxies and are the most powerful sources of gravitational waves accessible to space-based gravitational observatories. Some such mergers may occur in the presence of matter and ... More
The imposition of Cauchy data to the Teukolsky equation III: The rotating caseMar 16 1998We solve the problem of expressing the Weyl scalars $\psi $ that describe gravitational perturbations of a Kerr black hole in terms of Cauchy data. To do so we use geometrical identities (like the Gauss-Codazzi relations) as well as Einstein equations. ... More
The Samurai Project: verifying the consistency of black-hole-binary waveforms for gravitational-wave detectionJan 16 2009Mar 27 2009We quantify the consistency of numerical-relativity black-hole-binary waveforms for use in gravitational-wave (GW) searches with current and planned ground-based detectors. We compare previously published results for the $(\ell=2,| m | =2)$ mode of the ... More
Improved Moving Puncture Gauge Conditions for Compact Binary EvolutionsApr 25 2014Oct 06 2014Robust gauge conditions are critically important to the stability and accuracy of numerical relativity (NR) simulations involving compact objects. Most of the NR community use the highly robust---though decade-old---moving-puncture (MP) gauge conditions ... More
Systematic biases in parameter estimation of binary black-hole mergersOct 02 2012Parameter estimation of binary-black-hole merger events in gravitational-wave data relies on matched-filtering techniques, which, in turn, depend on accurate model waveforms. Here we characterize the systematic biases introduced in measuring astrophysical ... More
Consistency of post-Newtonian waveforms with numerical relativityDec 04 2006Oct 29 2007General relativity predicts the gravitational wave signatures of coalescing binary black holes. Explicit waveform predictions for such systems, required for optimal analysis of observational data, have so far been achieved using the post-Newtonian (PN) ... More
Mergers of black-hole binaries with aligned spins: Waveform characteristicsJul 06 2011Oct 05 2011We conduct a descriptive analysis of the multipolar structure of gravitational-radiation waveforms from equal-mass aligned-spin mergers, following an approach first presented in the complementary context of nonspinning black holes of varying mass ratio ... More
The Final Merger of Black-Hole BinariesOct 11 2010Dec 10 2010Recent breakthroughs in the field of numerical relativity have led to dramatic progress in understanding the predictions of General Relativity for the dynamical interactions of two black holes in the regime of very strong gravitational fields. Such black-hole ... More
Impact of mergers on LISA parameter estimation for nonspinning black hole binariesNov 05 2009Apr 15 2010We investigate the precision with which the parameters describing the characteristics and location of nonspinning black hole binaries can be measured with the Laser Interferometer Space Antenna (LISA). By using complete waveforms including the inspiral, ... More
Tunable filter imaging of high redshift quasar fieldsFeb 02 2012We have used the Taurus Tunable Filter to search for Lyman alpha emitters in the fields of three high redshift quasar fields: two at z~2.2 (MRC B1256-243 and MRC B2158-206) and one at z~4.5 (BR B0019-1522). Our observations had a field of view of around ... More
Black-hole binaries, gravitational waves, and numerical relativityOct 25 2010Nov 27 2010Understanding the predictions of general relativity for the dynamical interactions of two black holes has been a long-standing unsolved problem in theoretical physics. Black-hole mergers are monumental astrophysical events, releasing tremendous amounts ... More
Bethe logarithms for the 1 singlet S, 2 singlet S and 2 triplet S states of helium and helium-like ionsFeb 03 2000We have computed the Bethe logarithms for the 1 singlet S, 2 singlet S and 2 triplet S states of the helium atom to about seven figure-accuracy using a generalization of a method first developed by Charles Schwartz. We have also calculated the Bethe logarithms ... More
Testing General Relativity with Low-Frequency, Space-Based Gravitational-Wave DetectorsDec 21 2012Sep 13 2013We review the tests of general relativity that will become possible with space-based gravitational-wave detectors operating in the ~0.01mHz - 1Hz low-frequency band. The fundamental aspects of gravitation that can be tested include the presence of additional ... More
Gravitational wave extraction from an inspiraling configuration of merging black holesNov 17 2005We present new techniqes for evolving binary black hole systems which allow the accurate determination of gravitational waveforms directly from the wave zone region of the numerical simulations. Rather than excising the black hole interiors, our approach ... More
Dehn filling and the Thurston normAug 08 2016For a compact, orientable, irreducible 3-manifold with toroidal boundary that is not the product of a torus and an interval or a cable space, each boundary torus has a finite set of slopes such that, if avoided, the Thurston norm of a Dehn filling behaves ... More
A Model for Grid User ManagementJun 13 2003Registration and management of users in a large scale Grid computing environment presents new challenges that are not well addressed by existing protocols. Within a single Virtual Organization (VO), thousands of users will potentially need access to hundreds ... More
The collision of boosted black holesAug 28 1996We study the radiation from a collision of black holes with equal and opposite linear momenta. Results are presented from a full numerical relativity treatment and are compared with the results from a ``close-slow'' approximation. The agreement is remarkable, ... More
Sky localization of complete inspiral-merger-ringdown signals for nonspinning massive black hole binariesApr 29 2011We investigate the capability of LISA to measure the sky position of equal-mass, nonspinning black hole binaries, combining for the first time the entire inspiral-merger-ringdown signal, the effect of the LISA orbits, and the complete three-channel LISA ... More
Machine Learning Model of the Swift/BAT Trigger Algorithm for Long GRB Population StudiesSep 03 2015Feb 09 2016To draw inferences about gamma-ray burst (GRB) source populations based on Swift observations, it is essential to understand the detection efficiency of the Swift burst alert telescope (BAT). This study considers the problem of modeling the Swift/BAT ... More
Wave zone extraction of gravitational radiation in three-dimensional numerical relativityMar 23 2005Mar 24 2005We present convergent gravitational waveforms extracted from three-dimensional, numerical simulations in the wave zone and with causally disconnected boundaries. These waveforms last for multiple periods and are very accurate, showing a peak error to ... More
Binary black hole merger dynamics and waveformsFeb 07 2006Feb 09 2006We study dynamics and radiation generation in the last few orbits and merger of a binary black hole system, applying recently developed techniques for simulations of moving black holes. Our analysis of the gravitational radiation waveforms and dynamical ... More
The Laser Interferometer Space Antenna: Unveiling the Millihertz Gravitational Wave SkyJul 15 2019The first terrestrial gravitational wave interferometers have dramatically underscored the scientific value of observing the Universe through an entirely different window, and of folding this new channel of information with traditional astronomical data ... More
Vertex Ramsey problems in the hypercubeNov 01 2012If we 2-color the vertices of a large hypercube what monochromatic substructures are we guaranteed to find? Call a set S of vertices from Q_d, the d-dimensional hypercube, Ramsey if any 2-coloring of the vertices of Q_n, for n sufficiently large, contains ... More
Inspiralling black holes: the close limitMay 20 1999Using several approximations, we calculate an estimate of the gravitational radiation emitted when two equal mass black holes coalesce at the end of their binary inspiral. We find that about 1% of the mass energy of the pair will emerge as gravitational ... More