Results for "David Hartman"

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The independence number of HH-homogeneous graphs and a classification of MB-homogeneous graphsFeb 08 2019We show that the independence number of a countably infinite HH-homogeneous graph that does not contain the Rado graph as a spanning subgraph is finite and present a classification of MB-homogeneous graphs up to bimorphism-equivalence as a consequence. ... More
Homomorphism-homogeneous L-colored graphsApr 26 2012A relational structure is homomorphism-homogeneous (HH-homogeneous for short) if every homomorphism between finite induced substructures of the structure can be extended to a homomorphism over the whole domain of the structure. Similarly, a structure ... More
KOI-142, the King of Transit Variations, is a Pair of Planets near the 2:1 ResonanceApr 15 2013The Transit Timing Variations (TTVs) can be used as a diagnostic of gravitational interactions between planets in a multi-planet system. Many Kepler Objects of Interest (KOIs) exhibit significant TTVs, but KOI-142.01 stands out among them with an unrivaled, ... More
Morphism extension classes of countable $L$-colored graphsMay 04 2018In~\cite{Hartman:2014}, Hartman, Hubi\v cka and Ma\v sulovi\'c studied the hierarchy of morphism extension classes for finite $L$-colored graphs, that is, undirected graphs without loops where sets of colors selected from $L$ are assigned to vertices ... More
Small-world topology of functional connectivity in randomly connected dynamical systemsJun 18 2012Characterization of real-world complex systems increasingly involves the study of their topological structure using graph theory. Among global network properties, small-world property, consisting in existence of relatively short paths together with high ... More
Complexities of relational structuresSep 17 2013The relational complexity, introduced by G. Cherlin, G. Martin, and D. Saracino, is a measure of ultrahomogeneity of a relational structure. It provides an information on minimal arity of additional invariant relations needed to turn given structure into ... More
High Velocity Clouds: the Missing LinkJan 21 1999Hierarchical structure formation models predict the existence of large numbers of low velocity dispersion dark halos. Galaxy surveys find far fewer galaxies than predicted by analytical estimates and numerical simulations. In this paper, we suggest that ... More
Non-linear dependence and teleconnections in climate data: sources, relevance, nonstationarityNov 28 2012Quantification of relations between measured variables of interest by statistical measures of dependence is a common step in analysis of climate data. The term "connectivity" is used in the network context including the study of complex coupled dynamical ... More
Universal Spectrum of 2d Conformal Field Theory in the Large c LimitMay 20 2014Sep 19 2014Two-dimensional conformal field theories exhibit a universal free energy in the high temperature limit $T \to \infty$, and a universal spectrum in the Cardy regime, $\Delta \to \infty$. We show that a much stronger form of universality holds in theories ... More
Tropical Determinant of Integer Doubly-Stochastic MatricesMay 18 2010Let D(m,n) be the set of all the integer points in the m-dilate of the Birkhoff polytope of doubly-stochastic n by n matrices. In this paper we find the sharp upper bound on the tropical determinant over the set D(m,n). We define a version of the tropical ... More
Light Meson Mass Spectrum from Gauge Fields on Supergravity BackgroundsJun 23 1999We propose that the spectrum of light mesons (the $\pi$ and $\rho$, together with their radial excitations) can be calculated in the limit of vanishing light quark masses by studying gauge theory (open string theory) on suitable higher dimensional background ... More
The Hunt for Exomoons with Kepler (HEK): II. Analysis of Seven Viable Satellite-Hosting Planet CandidatesJan 09 2013Mar 06 2013From the list of 2321 transiting planet candidates announced by the Kepler Mission, we select seven targets with favorable properties for the capacity to dynamically maintain an exomoon and present a detectable signal. These seven candidates were identified ... More
A resonant pair of warm giant planets revealed by TESSFeb 11 2019We present the discovery of a pair of transiting giant planets, TOI-216b and c, using four sectors of TESS photometry. TOI-216 is a $0.87 M_{\odot}$ dwarf orbited by two transiters with radii of $8.2 R_{\oplus}$ and $11.3 R_{\oplus}$, and periods of $17.01$d ... More
The Hunt for Exomoons with Kepler (HEK): IV. A Search for Moons around Eight M-DwarfsJan 06 2014Jan 26 2014With their smaller radii and high cosmic abundance, transiting planets around cool stars hold a unique appeal. As part of our on-going project to measure the occurrence rate of extrasolar moons, we here present results from a survey focussing on eight ... More
The Detection and Characterization of a Nontransiting Planet by Transit Timing VariationsAug 04 2012The Kepler Mission is monitoring the brightness of ~150,000 stars searching for evidence of planetary transits. As part of the "Hunt for Exomoons with Kepler" (HEK) project, we report a planetary system with two confirmed planets and one candidate planet ... More
No Conclusive Evidence for Transits of Proxima b in MOST photometrySep 28 2016Dec 01 2016The analysis of Proxima Centauri's radial velocities recently led Anglada-Escud\'e et al. (2016) to claim the presence of a low mass planet orbiting the Sun's nearest star once every 11.2 days. Although the a-priori probability that Proxima b transits ... More
HAT-P-31b,c: A Transiting, Eccentric, Hot Jupiter and a Long-Period, Massive Third-BodyJun 06 2011Jul 07 2011We report the discovery of HAT-P-31b, a transiting exoplanet orbiting the V=11.660 dwarf star GSC 2099-00908. HAT-P-31b is the first HAT planet discovered without any follow-up photometry, demonstrating the feasibility of a new mode of operation for the ... More
HAT-P-27b: A hot Jupiter transiting a G star on a 3 day orbitJan 18 2011Mar 24 2011We report the discovery of HAT-P-27b, an exoplanet transiting the moderately bright G8 dwarf star GSC 0333-00351 (V=12.214). The orbital period is 3.039586 +/- 0.000012 d, the reference epoch of transit is 2455186.01879 +/- 0.00054 (BJD), and the transit ... More
A low density of 0.8 g/cc for the Trojan binary asteroid 617 PatroclusFeb 02 2006The Trojan population consists of two swarms of asteroids following the same orbit as Jupiter and located at the L4 and L5 Lagrange points of the Jupiter-Sun system (leading and following Jupiter by 60 degrees). The asteroid 617 Patroclus is the only ... More
HATNet Field G205: Follow-Up Observations of 28 Transiting-Planet candidates and Confirmation of the Planet HAT-P-8bDec 05 2008We report the identification of 32 transiting-planet candidates in HATNet field G205. We describe the procedures that we have used to follow up these candidates with spectroscopic and photometric observations, and we present a status report on our interpretation ... More
Holographic Entanglement Entropy from 2d CFT: Heavy States and Local QuenchesOct 06 2014Oct 22 2014We consider the entanglement entropy in 2d conformal field theory in a class of excited states produced by the insertion of a heavy local operator. These include both high-energy eigenstates of the Hamiltonian and time-dependent local quenches. We compute ... More
The Kerr/CFT CorrespondenceSep 25 2008Quantum gravity in the region very near the horizon of an extreme Kerr black hole (whose angular momentum and mass are related by J=GM^2) is considered. It is shown that consistent boundary conditions exist, for which the asymptotic symmetry generators ... More
Entanglement Scrambling in 2d Conformal Field TheoryJun 11 2015Aug 10 2015We investigate how entanglement spreads in time-dependent states of a 1+1 dimensional conformal field theory (CFT). The results depend qualitatively on the value of the central charge. In rational CFTs, which have central charge below a critical value, ... More
Large Semigroups of Cellular AutomataJul 04 2010Apr 29 2012In this article we consider semigroups of transformations of cellular automata which act on a fixed shift space. In particular, we are interested in two properties of these semigroups which relate to "largeness". The first property is ID and the other ... More
Discovery of a 552 Hz burst oscillation in the low-mass X-ray binary EXO 0748-676Oct 29 2009Feb 09 2010We report the detection of pulsations at 552 Hz in the rising phase of two type-I (thermonuclear) X-ray bursts observed from the accreting neutron star EXO 0748-676 in 2007 January and December, by the Rossi X-ray Timing Explorer. The fractional amplitude ... More
The Hunt for Exomoons with Kepler (HEK): III. The First Search for an Exomoon around a Habitable-Zone PlanetJun 06 2013Sep 09 2013Kepler-22b is the first transiting planet to have been detected in the habitable-zone of its host star. At 2.4 Earth radii, Kepler-22b is too large to be considered an Earth-analog, but should the planet host a moon large enough to maintain an atmosphere, ... More
HAT-P-65b and HAT-P-66b: Two Transiting Inflated Hot Jupiters and Observational Evidence for the Re-Inflation of Close-In Giant PlanetsSep 09 2016We present the discovery of the transiting exoplanets HAT-P-65b and HAT-P-66b, with orbital periods of 2.6055 d and 2.9721 d, masses of $0.527 \pm 0.083$ M$_{J}$ and $0.783 \pm 0.057$ M$_{J}$ and inflated radii of $1.89 \pm 0.13$ R$_{J}$ and $1.59^{+0.16}_{-0.10}$ ... More
HAT-P-50b, HAT-P-51b, HAT-P-52b, and HAT-P-53b: Three Transiting Hot Jupiters and a Transiting Hot Saturn From the HATNet SurveyMar 13 2015We report the discovery and characterization of four transiting exoplanets by the HATNet survey. The planet HAT-P-50b has a mass of 1.35 M_J and a radius of 1.29 R_J, and orbits a bright (V = 11.8 mag) M = 1.27 M_sun, R = 1.70 R_sun star every P = 3.1220 ... More
The Hunt for Exomoons with Kepler (HEK): V. A Survey of 41 Planetary Candidates for ExomoonsMar 18 2015Sep 24 2015We present a survey of 41 Kepler Objects of Interest (KOIs) for exomoons using Bayesian photodynamics, more than tripling the number of KOIs surveyed with this technique. We find no compelling evidence for exomoons although thirteen KOIs yield spurious ... More
Furstenberg entropy realizations for virtually free groups and lamplighter groupsOct 22 2012Jul 19 2015Let $(G,\mu)$ be a discrete group with a generating probability measure. Nevo shows that if $G$ has property (T) then there exists an $\epsilon>0$ such that the Furstenberg entropy of any $(G,\mu)$-stationary ergodic space is either zero or larger than ... More
Stabilizer Rigidity in Irreducible Group ActionsJul 29 2013Oct 22 2016We consider irreducible actions of locally compact product groups, and of higher rank semi-simple Lie groups. Using the intermediate factor theorems of Bader-Shalom and Nevo-Zimmer, we show that the action stabilizers, and all irreducible invariant random ... More
The Solar Solution: Tracking the Sun with Low Energy NeutrinosMay 05 2016As neutrinos become a significant background for projected dark matter experiments, the community will become concerned with determining if events counted in a dark matter experiment are good dark matter candidates or low-energy neutrinos from astrophysical ... More
Time Evolution of Entanglement Entropy from Black Hole InteriorsMar 05 2013Apr 22 2013We compute the time-dependent entanglement entropy of a CFT which starts in relatively simple initial states. The initial states are the thermofield double for thermal states, dual to eternal black holes, and a particular pure state, dual to a black hole ... More
Stellar rotational periods in the planet hosting open cluster PraesepeMay 15 2014By using the dense coverage of the extrasolar planet survey project HATNet, we Fourier analyze 381 high-probability members of the nearby open cluster Praesepe (Beehive/M44/NGC 2632). In addition to the detection of 10 variables (of \delta Scuti and other ... More
The long-term evolution of the spin, pulse shape, and orbit of the accretion-powered millisecond pulsar SAX J1808.4-3658Aug 01 2007Dec 16 2007We present a 7 yr timing study of the 2.5 ms X-ray pulsar SAX J1808.4-3658, an X-ray transient with a recurrence time of ~2 yr, using data from the Rossi X-ray Timing Explorer covering 4 transient outbursts (1998-2005). We verify that the 401 Hz pulsation ... More
Speed Limits for EntanglementDec 08 2015We show that in any relativistic system, entanglement entropy obeys a speed limit set by the entanglement in thermal equilibrium. The bound is derived from inequalities on relative entropy with respect to a thermal reference state. Thus the thermal state ... More
Multi-Epoch Multiwavelength Spectra and Models for Blazar 3C~279Feb 07 2001Of the blazars detected by EGRET in GeV gamma rays, 3C 279 is not only the best-observed by EGRET, but also one of the best-monitored at lower frequencies. We have assembled eleven spectra, from GHz radio through GeV gamma rays, from the time intervals ... More
Direct Observation of Hydrogen Adsorption Sites and Nano-Cage Formation in Metal-Organic Frameworks (MOF)Jul 09 2005The hydrogen adsorption sites in MOF5 were determined using neutron powder diffraction along with first-principles calculations. The metal-oxide cluster is primarily responsible for the adsorption while the organic linker plays only a secondary role. ... More
Symmetries of Holographic Minimal ModelsJan 14 2011May 12 2011It was recently proposed that a large N limit of a family of minimal model CFTs is dual to a certain higher spin gravity theory in AdS_3, where the 't Hooft coupling constant of the CFT is related to a deformation parameter of the higher spin algebra. ... More
Cooper pairing near charged black holesMar 09 2010We show that a quartic contact interaction between charged fermions can lead to Cooper pairing and a superconducting instability in the background of a charged asymptotically Anti-de Sitter black hole. For a massless fermion we obtain the zero mode analytically ... More
Linking Stellar Coronal Activity and Rotation at 500 Myr: A Deep Chandra Observation of M37Jul 08 2015Oct 29 2016Empirical calibrations of the stellar age-rotation-activity relation (ARAR) rely on observations of the co-eval populations of stars in open clusters. We used the Chandra X-ray Observatory to study M37, a 500-Myr-old open cluster that has been extensively ... More
Linking Stellar Coronal Activity and Rotation at 500 Myr: A Deep Chandra Observation of M37Jul 08 2015Empirical calibrations of the stellar age-rotation-activity relation (ARAR) rely on observations of the co-eval populations of stars in open clusters. We used the Chandra X-ray Observatory to study M37, a 500-Myr-old open cluster that has been extensively ... More
Stable Leader Election in Population Protocols Requires Linear TimeFeb 14 2015Aug 20 2016A population protocol *stably elects a leader* if, for all $n$, starting from an initial configuration with $n$ agents each in an identical state, with probability 1 it reaches a configuration $\mathbf{y}$ that is correct (exactly one agent is in a special ... More
Integrals derived from the doubling methodOct 21 2018In this note, we use a basic identity, derived from the generalized doubling integrals of \cite{C-F-G-K1}, in order to explain the existence of various global Rankin-Selberg integrals for certain $L$-functions. To derive these global integrals, we use ... More
The Detection of Two Distinct High Ionization States in a QSO Lyman Limit Absorption System: Evidence for Hierarchical Galaxy Formation at z ~ 3?Jan 19 1999We have detected two high ionization phases of gas in the z ~ 2.77 partial Lyman limit system (LLS) towards QSO 1157-3143. We detect the first phase by CIV and SiIV absorption, and the second phase -- which is either warmer or undergoing larger random ... More
Continuum Percolation for Quermass ModelJan 11 2012The continuum percolation for Markov (or Gibbs) germ-grain models is investigated. The grains are assumed circular with random radii on a compact support. The morphological interaction is the so-called Quermass interaction defined by a linear combination ... More
Site Disordered Spin Systems in the Gaussian Variational ApproximationJun 06 1996Dec 16 1996We define a replica field theory describing finite dimensional site disordered spin systems by introducing the notion of grand canonical disorder, where the number of spins in the system is random but quenched. A general analysis of this field theory ... More
Results for the LISA Phase Measurement System ProjectNov 01 2004Jan 11 2005This article presents some of the more topical results of a study into the LISA phase measurement system. This system is responsible for measuring the phase of the heterodyne signal caused by the interference of the laser beams between the local and far ... More
The RASNIK Real-Time Relative Alignment Monitor for the CDF Inner Tracking DetectorsDec 10 2002We describe the design and operation of the RASNIK optical relative alignment system designed for and installed on the CDF inner tracking detectors. The system provides low-cost minute-by-minute alignment monitoring with submicron precision. To reduce ... More
Splitting cycles in graphsApr 26 2012The goal of this paper is to describe a sufficient condition on cycles in graphs for which the edge ideal is splittable. We give an explicit splitting function for such ideals.
The transverse proximity effect in the z ~ 2 Lyman-alpha forest suggests QSO episodic lifetimes of ~1 MyrSep 12 2008We look for signs of the H~I transverse proximity effect in the spectra of 130 QSO pairs, most with transverse separations in the plane of the sky of 0.1 -- 3 Mpc at z ~ 2.2. We expected to see a decrease in Lyman-alpha forest HI absorption in the spectrum ... More
Comet Encounters and Carbon 14Nov 26 2012The $^{14}$C production of shock-accelerated particles is calculated in terms of the total energy released in energetic particles. The recently reported 1.2% jump in the $^{14}$C content of the atmosphere in the year C.E. 775, it is found, would require ... More
On Mach's critique of Newton and CopernicusNov 19 2003Maintaining the relativity of all motion, especially rotational motion, Mach denied the existence of absolute motion and absolute space. He maintained the equivalence of the Ptolemaic and the Copernican systems and the equivalence of a fixed bucket in ... More
Resonance-Enhanced Two-Photon Ionization (RETPI) of SiII and an Anomalous, Variable Intensity of the 1892A SiIII] Line in the Weigelt Blobs of Eta CarinaeFeb 16 2006The Si III] 1892A intercombination line shows an anomalously high intensity in spectra of the radiation-rich Weigelt blobs in the vicinity of Eta Carinae. The line disappears during the 100 days long spectral events occurring every 5.5 years. The aim ... More
VARTOOLS: A Program for Analyzing Astronomical Time-Series DataMay 22 2016This paper describes the VARTOOLS program, which is an open-source command-line utility, written in C, for analyzing astronomical time-series data, especially light curves. The program provides a general-purpose set of tools for processing light curves ... More
Higher Spin Black Holes from CFTFeb 29 2012Jun 14 2012Higher spin gravity in three dimensions has explicit black holes solutions, carrying higher spin charge. We compute the free energy of a charged black hole from the holographic dual, a 2d CFT with extended conformal symmetry, and find exact agreement ... More
Gamma-Ray Emission from the Broad-Line Radio Galaxy 3C111Aug 12 2008The broad-line radio galaxy 3C111 has been suggested as the counterpart of the gamma-ray source 3EGJ0416+3650. While 3C111 meets most of the criteria for a high-probability identification, like a bright flat-spectrum radio core and a blazar-like broadband ... More
An Abramov formula for stationary spaces of discrete groupsApr 24 2012Let (G,mu) be a discrete group equipped with a generating probability measure, and let Gamma be a finite index subgroup of G. A mu-random walk on G, starting from the identity, returns to Gamma with probability one. Let theta be the hitting measure, or ... More
Automaticity in Computation and Student Success in Introductory Physical Science CoursesAug 17 2016Sep 27 2016Between 1984 and 2011, the percentage of US bachelor degrees awarded in physics declined by 25%, in chemistry declined by 33%, and overall in physical sciences and engineering fell 40%. Data suggest that these declines are correlated to a deemphasis in ... More
Approximations of the domination number of a graphJan 21 2017Given a graph G, the domination number gamma(G) of G is the minimum order of a set S of vertices such that each vertex not in S is adjacent to some vertex in S. Equivalently, label the vertices from {0, 1} so that the sum over each closed neighborhood ... More
In Self-contradiction, Machian Geocentrism Entails Absolute SpaceJun 19 2014Luka Popov has attempted to advance Machian physics by maintaining that the heliocentric system must be replaced by Tycho Brahe's geocentric system. We show that while geocentrism relies on Mach's contention that accelerations are relative, this contention ... More
Photometric Survey for Stellar Clusters in the Outer Part of M33May 28 2008We present a catalog of 4780 extended sources from the outer field of M33. The catalog includes 73 previously identified clusters or planetary nebulae, 1153 likely background galaxies, and 3554 new candidate stellar clusters. The survey is based on deep ... More
The Gravitational Exclusion Principle and Null States in Anti-de Sitter SpaceJul 26 2011The holographic principle implies a vast reduction in the number of degrees of freedom of quantum gravity. This idea can be made precise in AdS_3, where the the stringy or gravitational exclusion principle asserts that certain perturbative excitations ... More
Warped Conformal Field TheoryOct 01 2012Oct 15 2012We study field theories in two spacetime dimensions invariant under a chiral scaling symmetry that acts only on right-movers. The local symmetries include one copy of the Virasoro algebra and a U(1) current algebra. This differs from the 2d conformal ... More
Holographic Derivation of Kerr-Newman Scattering Amplitudes for General Charge and SpinAug 26 2009Near-superradiant scattering of charged scalars and fermions by a near-extreme Kerr-Newman black hole and photons and gravitons by a near-extreme Kerr black hole are computed as certain Fourier transforms of correlators in a two-dimensional conformal ... More
A New Spin on Causality ConstraintsJan 28 2016Causality in a shockwave state is related to the analytic properties of a four-point correlation function. Extending recent results for scalar probes, we show that this constrains the couplings of the stress tensor to light spinning operators in conformal ... More
Causality Constraints in Conformal Field TheoryAug 31 2015Aug 03 2016Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In d-dimensional conformal field theory, we show how such constraints are encoded in crossing symmetry ... More
Property (T) and the Furstenberg Entropy of Nonsingular ActionsJun 17 2014Jun 30 2014We establish a new characterization of property (T) in terms of the Furstenberg entropy of nonsingular actions. Given any generating measure $\mu$ on a countable group $G$, A. Nevo showed that a necessary condition for $G$ to have property (T) is that ... More
Generic Stationary Measures and ActionsMay 09 2014Aug 14 2015Let $G$ be a countably infinite group, and let $\mu$ be a generating probability measure on $G$. We study the space of $\mu$-stationary Borel probability measures on a topological $G$ space, and in particular on $Z^G$, where $Z$ is any perfect Polish ... More
On Transshipment Games with Identical NewsvendorsMar 24 2013In a transshipment game, supply chain agents cooperate to transship surplus products. This note studies the effect of size of transshipment coalitions on the optimal production/order quantities. It characterizes these quantities for transshipment games ... More
Mach's relativity of rotation in light of contemporary physicsJul 24 2008Mach argued for a relational rather than an absolute notion of space, insisting that centrifugal forces inside a rotating object such as a bucket can be reproduced by keeping the bucket fixed and rotating the universe. In response to a paper of ours denying ... More
Laboratory oscillator strengths of Sc I in the near-infrared region for astrophysical applicationsSep 21 2015Context. Atomic data is crucial for astrophysical investigations. To understand the formation and evolution of stars, we need to analyse their observed spectra. Analysing a spectrum of a star requires information about the properties of atomic lines, ... More
Averaged Null Energy Condition from CausalityOct 17 2016Unitary, Lorentz-invariant quantum field theories in flat spacetime obey microcausality: commutators vanish at spacelike separation. For interacting theories in more than two dimensions, we show that this implies that the averaged null energy, $\int du ... More
The Kerr-Fermi SeaDec 21 2009The presence of a massive scalar field near a Kerr black hole is known to produce instabilities associated with bound superradiant modes. In this paper we show that for massive fermions, rather than inducing an instability, the bound superradiant modes ... More
Magnetic Correlations in a Periodic Anderson Model with Non-Uniform Conduction Electron CoordinationJan 26 2016Feb 01 2016The Periodic Anderson Model (PAM) is widely studied to understand strong correlation physics and especially the competition of antiferromagnetism and singlet formation. Quantum Monte Carlo (QMC) studies have focused both on issues such as the nature of ... More
A Systematic Search for Short-term Variability of EGRET SourcesApr 18 2000The 3rd EGRET Catalog of High-energy Gamma-ray Sources contains 170 unidentified sources, and there is great interest in the nature of these sources. One means of determining source class is the study of flux variability on time scales of days; pulsars ... More
The Anti-Coincidence Detector for the GLAST Large Area TelescopeFeb 21 2007This paper describes the design, fabrication and testing of the Anti-Coincidence Detector (ACD) for the Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT). The ACD is LAT first-level defense against the charged cosmic ray background ... More
No Conclusive Evidence for Transits of Proxima b in MOST photometrySep 28 2016The analysis of Proxima Centauri's radial velocities recently led Anglada-Escud\'e et al. (2016) to claim the presence of a low mass planet orbiting the Sun's nearest star once every 11.2 days. Although the a-priori probability that Proxima b transits ... More
A Katznelson-Tzafriri theorem for measuresOct 06 2014This article generalises the well-known Katznelson-Tzafriri theorem for a $C_0$-semigroup $T$ on a Banach space $X$, by removing the assumption that a certain measure in the original result be absolutely continuous. In an important special case the rate ... More
Strategies for The Determination of phi3 in B- -> D0 K-Mar 30 2001Direct CP violation in decays such as B- -> D0 K- is sensitive to the CKM angle phi_3 because these decays allow the interference of b-quark to c-quark with b-quark to u-quark transitions. Indeed, phi_3 may be determined if one can infer the strong phase ... More
Digit permutations revisitedMay 12 2016We discuss here characteristic $p$ $L$-series as well as the group $S_{(q)}$ which appears to act as symmetries of these functions. We explain various actions of $S_{(q)}$ that arise naturally in the theory as well as extensions of these actions. In general ... More
Equations of Riemann surfaces with automorphismsJul 16 2016We present an algorithm for computing equations of canonically embedded Riemann surfaces with automorphisms. A variant of this algorithm with many heuristic improvements is used to produce equations of Riemann surfaces $X$ with large automorphism groups ... More
Submersions and effective descent of etale morphismsOct 12 2007Mar 05 2010Using the flatification by blow-up result of Raynaud and Gruson, we obtain new results for submersive and subtrusive morphisms. We show that universally subtrusive morphisms, and in particular universally open morphisms, are morphisms of effective descent ... More
Information as Distinctions: New Foundations for Information TheoryJan 23 2013Jan 26 2013The logical basis for information theory is the newly developed logic of partitions that is dual to the usual Boolean logic of subsets. The key concept is a "distinction" of a partition, an ordered pair of elements in distinct blocks of the partition. ... More
A Direct Proof of BCFW Recursion for Twistor-StringsJul 01 2010This paper gives a direct proof that the leading trace part of the genus zero twistor-string path integral obeys the BCFW recursion relation. This is the first complete proof that the twistor-string correctly computes all tree amplitudes in maximally ... More
Encoding !-tensors as !-graphs with neighbourhood ordersNov 05 2015Diagrammatic reasoning using string diagrams provides an intuitive language for reasoning about morphisms in a symmetric monoidal category. To allow working with infinite families of string diagrams, !-graphs were introduced as a method to mark repeated ... More
Spectral expansion of Schwartz linear operatorsApr 19 2011May 29 2011In this paper we prove and apply a theorem of spectral expansion for Schwartz linear operators which have an S-linearly independent Schwartz eigenfamily. This type of spectral expansion is the analogous of the spectral expansion for self-adjoint operators ... More
Internally heated convection beneath a poor conductorJun 29 2016We consider convection in an internally heated layer of fluid that is bounded below by a perfect insulator and above by a poor conductor. The poorly conducting boundary is modelled by a fixed heat flux. Using solely analytical methods, we find linear ... More
A Quantum Hall Fluid of VorticesJun 26 2003Jul 03 2003In this note we demonstrate that vortices in a non-relativistic Chern-Simons theory form a quantum Hall fluid. We show that the vortex dynamics is controlled by the matrix mechanics previously proposed by Polychronakos as a description of the quantum ... More
The Moduli Space of BPS Domain WallsFeb 01 2002Apr 25 2002N=2 SQED with several flavors admits multiple, static BPS domain wall solutions. We determine the explicit two-kink metric and examine the dynamics of colliding domain walls. The multi-kink metric has a toric Kahler structure and we reduce the Kahler ... More
The Holographic Dual of AdS3 x S3 x S3 x S1Feb 20 2014Jan 20 2016We construct the two dimensional N=(0,4) gauge theory that lives on the world volume of D1-branes and intersecting D5-branes. We conjecture that this theory flows in the infra-red to a fixed point with large N=(4,4) superconformal symmetry. The central ... More
Superconformal Vortex StringsOct 19 2006Nov 27 2006We study the low-energy dynamics of semi-classical vortex strings living above Argyres-Douglas superconformal field theories. The worldsheet theory of the string is shown to be a deformation of the CP^N model which flows in the infra-red to a superconformal ... More
Classicality of quantum information processingAug 22 2001May 01 2002The ultimate goal of the classicality programme is to quantify the amount of quantumness of certain processes. Here, classicality is studied for a restricted type of process: quantum information processing (QIP). Under special conditions, one can force ... More
Constructing local L-packets for tame unitary groupsNov 29 2013We generalize the work of DeBacker and Reeder to the case of unitary groups split by a tame extension. The approach is broadly similar and the restrictions on the parameter the same, but many of the details of the arguments differ. Let $G$ be a unitary ... More
Non-commutative vs. Commutative Descriptions of D-brane BIonsFeb 02 2000Feb 09 2000The U(1) gauge theory on a D3-brane with non-commutative worldvolume is shown to admit BIon-like solutions which saturate a BPS bound on the energy. The mapping of these solutions to ordinary fields is found exactly, namely non-perturbatively in the non-commutativity ... More
Developing and Analyzing Boundary Detection Operators Using Probabilistic ModelsMar 27 2013Most feature detectors such as edge detectors or circle finders are statistical, in the sense that they decide at each point in an image about the presence of a feature, this paper describes the use of Bayesian feature detectors.
On the Ramsey multiplicity of complete graphsNov 30 2007We show that, for $n$ large, there must exist at least \[\frac{n^t}{C^{(1+o(1))t^2}}\] monochromatic $K_t$s in any two-colouring of the edges of $K_n$, where $C \approx 2.18$ is an explicitly defined constant. The old lower bound, due to Erd\H{o}s \cite{E62}, ... More
Graphs with few paths of prescribed length between any two verticesNov 04 2014We use a variant of Bukh's random algebraic method to show that for every natural number $k \geq 2$ there exists a natural number $\ell$ such that, for every $n$, there is a graph with $n$ vertices and $\Omega_k(n^{1 + 1/k})$ edges with at most $\ell$ ... More
Combinatorial theorems relative to a random setApr 12 2014May 22 2014We describe recent advances in the study of random analogues of combinatorial theorems.
Mapping R&D support infrastructures: A scientometric and webometric study of UK science parksJul 27 2014This thesis analyses UK SPs with an informetric approach to study (1) the role of public science and HEIs in research and development (R&D) networks associated with SPs, and (2) the web-based patterns that reflect the configuration of R&D support infrastructures ... More