Results for "Graham M. Harper"

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Astro2020: Molecular Masers as Probes of the Dynamic Atmospheres of Dying StarsMar 13 2019More than half of the dust and heavy element enrichment in galaxies originates from the winds and outflows of evolved, low-to-intermediate mass stars on the asymptotic giant branch (AGB). However, numerous details of the physics of late-stage stellar ... More
Astro2020: Unlocking the Secrets of Late-Stage Stellar Evolution and Mass Loss through Radio Wavelength ImagingMar 13 2019During the late phases of evolution, low-to-intermediate mass stars like our Sun undergo periods of extensive mass loss, returning up to 80% of their initial mass to the interstellar medium. This mass loss profoundly affects the stellar evolutionary history, ... More
CARMA CO(J = 2 - 1) Observations of the Circumstellar Envelope of BetelgeuseJun 19 2012We report radio interferometric observations of the 12C16O 1.3 mm J = 2-1 emission line in the circumstellar envelope of the M supergiant Alpha Ori and have detected and separated both the S1 and S2 flow components for the first time. Observations were ... More
The Secret Lives of Cepheids: $δ$ Cep -- the Prototype of a New Class of Pulsating X-ray Variable StarsFeb 21 2017From our Secret Lives of Cepheids program, the prototype Classical Cepheid, $\delta$ Cep, is found to be an X-ray source with periodic pulsation-modulated X-ray variations. This finding complements our earlier reported phase-dependent FUV--UV emissions ... More
Science with an ngVLA: Stellar Activity on Red Giant and Supergiant Stars: Mass Loss and the Evolution of the Stellar DynamoOct 22 2018In this Chapter we examine the role of the ngVLA to further our understanding of the different manifestations of convective or turbulence-driven stellar activity on red giant and supergiant stars. The combination of high spatial resolution and high sensitivity ... More
Morse matchings on polytopesJul 25 2011We show how to construct homology bases for certain CW complexes in terms of discrete Morse theory and cellular homology. We apply this technique to study certain subcomplexes of the half cube polytope studied in previous works. This involves constructing ... More
MUSE CSP: An Extension to the Constraint Satisfaction ProblemNov 01 1996This paper describes an extension to the constraint satisfaction problem (CSP) called MUSE CSP (MUltiply SEgmented Constraint Satisfaction Problem). This extension is especially useful for those problems which segment into multiple sets of partially shared ... More
Mass Transport Processes and their Roles in the Formation, Structure, and Evolution of Stars and Stellar SystemsMar 13 2009We summarize some of the compelling new scientific opportunities for understanding stars and stellar systems that can be enabled by sub-mas angular resolution, UV/Optical spectral imaging observations, which can reveal the details of the many dynamic ... More
Discovery Potential for GMSB Supersymmetry in ATLAS using the $Zγ+ \not E_T$ Final State at a center of mass energy of $\sqrt{s}$=10 \TeVOct 21 2009We have studied the sensitivity of the ATLAS detector for supersymmetric neutralino signals in the $Z\gamma +\notE_{T}$ final state in a GMSB model in which the Higgsino-like neutralino is NLSP. This study considers the reaction of $pp \ra \tilde{\chi}^{0}_{1} ... More
On the uniform spread of almost simple symplectic and orthogonal groupsMar 28 2017Jul 18 2017A group is $\frac{3}{2}$-generated if every non-identity element is contained in a generating pair. A conjecture of Breuer, Guralnick and Kantor from 2008 asserts that a finite group is $\frac{3}{2}$-generated if and only if every proper quotient of the ... More
On instanton homology of corks W_nApr 18 2013We consider a family of corks, denoted $W_n$, constructed by Akbulut and Yasui. Each cork gives rise to an exotic structure on a smooth 4-manifold via a twist $\tau$ on its boundary $\Sigma_n = \partial W_n$. We compute the instanton Floer homology of ... More
The Replicator Equation as an Inference DynamicNov 09 2009May 03 2010The replicator equation is interpreted as a continuous inference equation and a formal similarity between the discrete replicator equation and Bayesian inference is described. Further connections between inference and the replicator equation are given ... More
Entropy Rates of the Multidimensional Moran Processes and GeneralizationsJan 13 2014The interrelationships of the fundamental biological processes natural selection, mutation, and stochastic drift are quantified by the entropy rate of Moran processes with mutation, measuring the long-run variation of a Markov process. The entropy rate ... More
A Population-centric Approach to the Beauty Contest GameMay 07 2010Dec 13 2014An population-centric analysis for a version of the p-beauty contest game is given for the two-player, finite population, and infinite population cases. Winning strategies are characterized in terms of iterative thinking relative to the population. To ... More
PDEs and hypercomplex analytic functionsSep 07 2016Hypercomplex numbers are unital algebras over the real numbers. We offer a short demonstration of the practical value of hypercomplex analytic functions in the field of partial differential equations.
Escort Evolutionary Game TheoryNov 09 2009Feb 24 2012A family of replicator-like dynamics, called the escort replicator equation, is constructed using information-geometric concepts and generalized information entropies and diverenges from statistical thermodynamics. Lyapunov functions and escort generalizations ... More
The Inherent Randomness of Evolving PopulationsMar 08 2013Mar 27 2013The entropy rates of the Wright-Fisher process, the Moran process, and generalizations are computed and used to compare these processes and their dependence on standard evolutionary parameters. Entropy rates are measures of the variation dependent on ... More
Factorization for stacks and boundary complexesJun 24 2017We prove a weak factorization result on birational maps of Deligne-Mumford stacks, and deduce the following: Let $U \subset X$ be an open embedding of smooth Deligne-Mumford stacks such that $D = X-U$ is a normal crossings divisor, then the the simple ... More
Approximate Convex Hulls: sketching the convex hull using curvatureFeb 27 2017Jun 14 2017Convex hulls are fundamental objects in computational geometry. In moderate dimensions or for large numbers of vertices, computing the convex hull can be impractical due to the computational complexity of convex hull algorithms. In this article we approximate ... More
Fluorine in the solar neighborhood - is it all produced in AGB-stars?Jun 18 2014The origin of 'cosmic' fluorine is uncertain, but there are three proposed production sites/mechanisms: AGB stars, $\nu$ nucleosynthesis in Type II supernovae, and/or the winds of Wolf-Rayet stars. The relative importance of these production sites has ... More
Capability of Detecting Ultra-Violet Counterparts of Gravitational Waves with GLUVJun 19 2017Sep 04 2017With the discovery of gravitational waves (GW), attention has turned towards detecting counterparts to these sources. In discussions on counterpart signatures and multi-messenger follow-up strategies to GW detections, ultra-violet (UV) signatures have ... More
Blue mussel shell shape plasticity and natural environments: a quantitative approachFeb 13 2018Shape variability represents an important direct response of organisms to selective environments. Here, we use a combination of geometric morphometrics and generalised additive mixed models (GAMMs) to identify spatial patterns of natural shell shape variation ... More
Chromatic transit light curves of disintegrating rocky planetsJul 20 2018Context. Kepler observations have revealed a class of short period exoplanets, of which Kepler-1520 b is the prototype, which have comet-like dust tails thought to be the result of small, rocky planets losing mass. The shape and chromaticity of the transits ... More
A Tale of Three RuntimesSep 05 2014This contribution discusses the automatic generation of event-driven, tuple-space based programs for task-oriented execution models from a sequential C specification. We developed a hierarchical mapping solution using auto-parallelizing compiler technology ... More
Detection of thermal radio emission from a single coronal giantNov 25 2016We report the detection of thermal continuum radio emission from the K0 III coronal giant Pollux ($\beta$ Gem) with the Karl G. Jansky Very Large Array (VLA). The star was detected at 21 and 9 GHz with flux density values of $150\pm21$ and $43\pm8\,\mu$Jy, ... More
Metastability in the dilute Ising modelSep 02 2011Consider Glauber dynamics for the Ising model on the hypercubic lattice with a positive magnetic field. Starting from the minus configuration, the system initially settles into a metastable state with negative magnetization. Slowly the system relaxes ... More
Retardation effects in induced atomic dipole-dipole interactionsOct 18 2016We present mean-field calculations of azimuthally averaged retarded dipole-dipole interactions in a Bose-Einstein condensate induced by a laser, at both long and short wavelengths. Our calculations demonstrate that dipole-dipole interactions become significantly ... More
Feedback in the Antennae Galaxies (NGC 4038/9): I. High-Resolution Infrared Spectroscopy of Winds from Super Star ClustersJun 26 2007We present high-resolution (R ~ 24,600) near-IR spectroscopy of the youngest super star clusters (SSCs) in the prototypical starburst merger, the Antennae Galaxies. These SSCs are young (3-7 Myr old) and massive (10^5 - 10^7 M_sun for a Kroupa IMF) and ... More
Testing models of inflation with CMB non-gaussianityJul 11 2007Two different predictions for the primordial curvature fluctuation bispectrum are compared through their effects on the Cosmic Microwave Background temperature fluctuations. The first has a local form described by a single parameter f_{NL}. The second ... More
Far-UV Emissions of the Sun in Time: Probing Solar Magnetic Activity and Effects on Evolution of Paleo-Planetary AtmospheresMay 15 2003We present and analyze FUSE observations of six solar analogs. These are single, main-sequence G0-5 strs selected as proxies for the Sun at several stages of its main-sequence lifetime. The emission features in the FUSE 920-1180 A wavelength range allow ... More
Hubble Space Telescope Constraints on the Winds and Astrospheres of Red Giant StarsJul 26 2016We report on an ultraviolet spectroscopic survey of red giants observed by the Hubble Space Telescope, focusing on spectra of the Mg II h & k lines near 2800 A in order to study stellar chromospheric emission, winds, and astrospheric absorption. We focus ... More
Near-IR Spectroscopy and Population Synthesis of Super Star Clusters in NGC 1569Dec 05 2000We present H- and K-band NIRSPEC spectroscopy of super star clusters (SSCs) in the irregular starburst galaxy NGC 1569, obtained at the Keck Observatory. We fit these photospheric spectra to NextGen model atmospheres to obtain effective spectral types ... More
Discrete analogues of Dirac's magnetic monopole and binary polyhedral groupsSep 30 2013We introduce some discrete analogues of the Dirac magnetic monopole on a unit sphere S^2 and explain how to compute the corresponding spectrum using the representation theory of finite groups. The main examples are certain magnetic Laplacians on the regular ... More
Constraints on discrete symmetries from anomaly cancellation in compactified superstring theoriesJul 14 1993Compactified string theories give rise to discrete symmetries which are essential if they are to provide a realistic low energy theory. We find that in a class of four dimensional string theories these symmetries are constrained by similar conditions ... More
Asymptotically exact inference in differentiable generative modelsMay 25 2016Mar 02 2017Many generative models can be expressed as a differentiable function of random inputs drawn from some simple probability density. This framework includes both deep generative architectures such as Variational Autoencoders and a large class of procedurally ... More
Universal Bell Correlations Do Not ExistDec 16 2016We prove that there is no finite-alphabet nonlocal box that generates exactly those correlations that can be generated using a maximally entangled pair of qubits. More generally, we prove that if some finite-alphabet nonlocal box is strong enough to simulate ... More
Particle production and reheating in the inflationary universeOct 11 2008Oct 15 2008Thermal field theory is applied to particle production rates in inflationary models, leading to new results for catalysed, or two-stage decay, where massive fields act as decay channels for the production of light fields. A numerical investigation of ... More
Leptogenesis from loop effects in curved spacetimeDec 07 2015Jul 13 2017We describe a new mechanism - radiatively-induced gravitational leptogenesis - for generating the matter-antimatter asymmetry of the Universe. We show how quantum loop effects in C and CP violating theories cause matter and antimatter to propagate differently ... More
Non-separability of the Gelfand space of measure algebrasMar 18 2016Jun 27 2016We prove that there exists uncountably many pairwise disjoint open subsets of the Gelfand space of the measure algebra on any locally compact non-discrete abelian group which shows that this space is not separable (in fact, we prove this assertion for ... More
Normal Form for Edge MetricsJul 05 2012A normal form for edge metrics is derived under the necessary conditions that the metric be normalized and exact. The normal forms for such an edge metric are shown to be in 1-1 correspondence with representative metrics for a reduced conformal infinity ... More
Continuously tempered Hamiltonian Monte CarloApr 11 2017Hamiltonian Monte Carlo (HMC) is a powerful Markov chain Monte Carlo (MCMC) method for performing approximate inference in complex probabilistic models of continuous variables. In common with many MCMC methods, however, the standard HMC approach performs ... More
The F-signature and strong F-regularityAug 08 2002Nov 25 2002We show that the F-signature of a local ring of characteristic p, defined by Huneke and Leuschke, is positive if and only if the ring is strongly F-regular.
A Unified Term for Directed and Undirected Motility in Collective Cell InvasionMar 22 2012In this paper we develop mathematical models for collective cell motility. Initially we develop a model using a linear diffusion-advection type equation and fit the parameters to data from cell motility assays. This approach is helpful in classifying ... More
On geometric quantization of the Dirac magnetic monopoleMar 31 2011Jul 24 2013We give a simple derivation of the spectrum of the Dirac magnetic monopole on a unit sphere based on geometric quantization and the Frobenius reciprocity formula. We also briefly discuss the generalisations of Dirac magnetic monopole to any coadjoint ... More
Second order splitting for a class of fourth order equationsNov 11 2017Mar 31 2019We formulate a well-posedness and approximation theory for a class of generalised saddle point problems. In this way we develop an approach to a class of fourth order elliptic partial differential equations using the idea of splitting into coupled second ... More
Systematic trend of water vapour absorption in red giant atmospheres revealed by high resolution TEXES 12 micron spectraOct 15 2014The structures of the outer atmospheres of red giants are very complex. The notion of large optically thick molecular spheres around the stars (MOLspheres) has been invoked in order to explain e.g. spectro-interferometric observations. However, high-resolution ... More
Small-N collisional dynamics III: The battle for the realm of not-so-small-NJul 06 2017In this paper, the third in the series, we continue our study of combinatorics in chaotic Newtonian dynamics. We study the chaotic four-body problem in Newtonian gravity assuming finite-sized particles, and we focus on interactions that produce direct ... More
Computational Higher Type Theory II: Dependent Cubical RealizabilityJun 30 2016This is the second in a series of papers extending Martin-L\"{o}f's meaning explanation of dependent type theory to account for higher-dimensional types. We build on the cubical realizability framework for simple types developed in Part I, and extend ... More
The scissors mode from a different perspectiveJan 05 2015Apr 09 2015The scissors mode, a magnetic dipole excitation-mainly orbital is usually discussed in terms of a transition from a J=0^{+} ground state to a J=1^{+} excited state. This is understandable because it follows from the way the experiment is performed-e.g. ... More
Wave functions of the Q.Q interaction in terms of unitary 9-j coefficientsJun 19 2013Mar 20 2015We obtain wave functions for 2 protons and 2 neutrons in the g_{9/2} shell expressed as column vectors with amplitudes D(J_{p},J_{n}). When we use a quadrupole-quadrupole interaction (Q.Q) we get, in many cases, a very strong overlap with wave functions ... More
On Equivalence and Canonical Forms in the LF Type TheoryOct 11 2001Decidability of definitional equality and conversion of terms into canonical form play a central role in the meta-theory of a type-theoretic logical framework. Most studies of definitional equality are based on a confluent, strongly-normalizing notion ... More
A Separation Logic for Concurrent Randomized ProgramsFeb 08 2018Nov 21 2018We present Polaris, a concurrent separation logic with support for probabilistic reasoning. As part of our logic, we extend the idea of coupling, which underlies recent work on probabilistic relational logics, to the setting of programs with both probabilistic ... More
Computational Higher Type Theory IV: Inductive TypesJan 04 2018Jul 18 2018This is the fourth in a series of papers extending Martin-L\"of's meaning explanation of dependent type theory to higher-dimensional types. In this installment, we show how to define cubical type systems supporting a general schema of indexed cubical ... More
Bar constructions and Quillen homology of modules over operadsFeb 16 2008Sep 27 2009We show that topological Quillen homology of algebras and modules over operads in symmetric spectra can be calculated by realizations of simplicial bar constructions. Working with several model category structures, we give a homotopical proof after showing ... More
A Casson-Lin type invariant for linksJul 06 2009Nov 23 2009We define an integer valued invariant for two-component links in S^3 by counting projective SU(2) representations of the link group having non-trivial second Stiefel-Whitney class. We show that our invariant is, up to sign, the linking number of the link. ... More
The Riemann zeta function in short intervals [after Najnudel, and Arguin, Belius, Bourgade, Radziwiłł, and Soundararajan]Apr 17 2019This is the text to accompany my Bourbaki seminar from 30th March 2019, on the maximum size of the Riemann zeta function in "almost all" intervals of length 1 on the critical line. It surveys the conjecture of Fyodorov--Hiary--Keating on the behaviour ... More
Can the Sierpinski graph be embedded in the Hamming graph?Sep 21 2016The (generalized & expanded) Sierpinski graph, S(n,m), and the Hamming graph have the same set of vertices (n-tuples from the set {0,1,...,m-1}. The edges of both are (unordered) pairs of vertices. Each set of edges is defined by a different property ... More
The edge-isorperimetric problem on Sierpinski graphsOct 06 2016Some families of graphs, such as the n-cubes and Sierpinski gaskets, are self-similar. In this paper we show how such recursive structure can be used systematically to prove isoperimetric theorems.
Instanton Floer homology for two-component linksJan 22 2010Sep 25 2011For any link of two components in an integral homology sphere, we define an instanton Floer homology whose Euler characteristic is the linking number between the components of the link. We relate this Floer homology to the Kronheimer-Mrowka instanton ... More
TEXES Observations of M Supergiants: Dynamics and Thermodynamics of Wind AccelerationJun 25 2009We have detected [Fe II] 17.94 um and 24.52 um emission from a sample of M supergiants using TEXES on the IRTF. These low opacity emission lines are resolved at R = 50, 000 and provide new diagnostics of the dynamics and thermodynamics of the stellar ... More
Stability of Anomalous Floquet Edge UnitariesSep 20 2016It has recently been shown that periodically driven noninteracting systems may exhibit anomalous chiral edge modes, despite hosting bands with trivial topology. We obtain many-body versions of such drives, corresponding to class A, which exhibit anomalous ... More
The Range of a Steiner OperationAug 27 2016This paper answers a fundamental question in the theory of Steiner operations (StOps) as defined and studied in the monograph, "Global Methods for Combinatorial Isoperimetric Problems" (GMCIP). StOps are morphisms for combinatorial isoperimetric problems, ... More
Homotopy theory of modules over operads and non-Sigma operads in monoidal model categoriesDec 31 2007Jun 03 2009This paper studies the existence of model category structures on algebras and modules over operads in monoidal model categories.
High-Energy Photon and Particle Effects onExoplanet Atmospheres and HabitabilityMar 29 2019It is now recognized that energetic stellar photon and particle radiation evaporates and erodes planetary atmospheres and controls upper atmospheric chemistry. Key exoplanet host stars will be too faint at X-ray wavelengths for accurate characterization ... More
Electronic damping of molecular motion at metal surfacesSep 30 2009A method for the calculation of the damping rate due to electron-hole pair excitation for atomic and molecular motion at metal surfaces is presented. The theoretical basis is provided by Time Dependent Density Functional Theory (TDDFT) in the quasi-static ... More
Two jets from the Orion (M42) `proplyds' - kinematics, morphologies and originsJul 29 2002A spatially unresolved velocity feature, with an approaching radial velocity of ~100 km/s with respect to the systemic radial velocity, in a position-velocity array of [O III] 5007 line profiles is identified as the kinematical counterpart of a jet from ... More
Exact results for one-dimensional disordered bosons with strong repulsionAug 12 2004May 13 2005We study one-dimensional incommensurate bosons with strong repulsive interactions and weak disorder. In analogy to the clean Tonks-Girardeau gas, a Bose-Fermi mapping expresses this problem in terms of disordered free fermions. Thereby many known results ... More
A constitutive model for brittle granular materials considering the competition between breakage and dilationFeb 20 2019A constitutive model is presented for brittle granular materials based on a recent reformulation of the breakage mechanics theory. Compared with previous breakage mechanics-based models, the proposed model is improved to capture strain softening towards ... More
A concurrent precursor inflow method for Large Eddy Simulations and applications to finite length wind farmsMay 05 2014In order to enable simulations of developing wind turbine array boundary layers with highly realistic inflow conditions a concurrent precursor method for Large Eddy Simulations is proposed. In this method we consider two domains simultaneously, i.e. in ... More
ALMA Observations of Anisotropic Dust Mass-loss in the Inner Circumstellar Environment of the Red Supergiant VY Canis MajorisOct 07 2014Nov 27 2014The processes leading to dust formation and the subsequent role it plays in driving mass loss in cool evolved stars is an area of intense study. Here we present high resolution ALMA Science Verification data of the continuum emission around the highly ... More
A Note on the Uniform Kan Condition in Nominal Cubical SetsJan 23 2015Bezem, Coquand, and Huber have recently given a constructively valid model of higher type theory in a category of nominal cubical sets satisfying a novel condition, called the uniform Kan condition (UKC), which generalizes the standard cubical Kan condition ... More
Estimating the fidelity of T gates using standard interleaved randomized benchmarkingAug 09 2016Dec 20 2016Randomized benchmarking (RB) is an important protocol for robustly characterizing the error rates of quantum gates. The technique is typically applied to the Clifford gates since they form a group that satisfies a convenient technical condition of forming ... More
Homotopy completion and topological Quillen homology of structured ring spectraFeb 07 2011Feb 06 2013Working in the context of symmetric spectra, we describe and study a homotopy completion tower for algebras and left modules over operads in the category of modules over a commutative ring spectrum (e.g., structured ring spectra). We prove a strong convergence ... More
The SU(N) Casson-Lin invariants for linksJun 11 2015Dec 03 2015We introduce the $SU(N)$ Casson-Lin invariants for links $L$ in $S^3$ with more than one component. Writing $L = \ell_1 \cup \cdots \cup \ell_n$, we require as input an $n$-tuple $(a_1,\ldots, a_n) \in {\mathbb Z}^n$ of labels, where $a_j$ is associated ... More
Higher homotopy excision and Blakers-Massey theorems for structured ring spectraFeb 19 2014May 05 2016Working in the context of symmetric spectra, we prove higher homotopy excision and higher Blakers-Massey theorems, and their duals, for algebras and left modules over operads in the category of modules over a commutative ring spectrum (e.g., structured ... More
A Monadic Formalization of ML5Sep 14 2010ML5 is a programming language for spatially distributed computing, based on a Curry-Howard correspondence with the modal logic S5. Despite being designed by a correspondence with S5 modal logic, the ML5 programming language differs from the logic in several ... More
Fault-Tolerant Logical Gates in the IBM Quantum ExperienceJun 06 2018Jan 30 2019Quantum computers will require encoding of quantum information to protect them from noise. Fault-tolerant quantum computing architectures illustrate how this might be done but have not yet shown a conclusive practical advantage. Here we demonstrate that ... More
On the uniform domination number of a finite simple groupOct 19 2017Apr 10 2018Let $G$ be a finite simple group. By a theorem of Guralnick and Kantor, $G$ contains a conjugacy class $C$ such that for each non-identity element $x \in G$, there exists $y \in C$ with $G = \langle x,y\rangle$. Building on this deep result, we introduce ... More
A nilpotent Whitehead theorem for TQ-homology of structured ring spectraJun 26 2018Oct 12 2018The aim of this short paper is to prove a TQ-Whitehead theorem for nilpotent structured ring spectra. We work in the framework of symmetric spectra and algebras over operads in modules over a commutative ring spectrum. Our main result can be thought of ... More
OH maser disc and outflow in the Orion-BN/KL regionJan 26 2006MERLIN measurements of 1.6-GHz OH masers associated with Orion-BN/KL are presented, and the data are compared with data on other masers, molecular lines, compact radio continuum sources and infrared sources in the region. OH masers are detected over an ... More
Longitudinal spin diffusion in a nondegenerate trapped $^{87}$Rb gasJan 16 2015May 30 2015Longitudinal spin diffusion of two pseudo-spin domains is studied in a trapped $^{87}$Rb sample above quantum degeneracy, and the effect of coherence in the domain wall on the dynamics of the system is investigated. Coherence in a domain wall leads to ... More
The time-evolution of DCIS size distributions with applications to breast cancer growth and progressionApr 22 2013Jun 25 2013Ductal carcinoma {\em in situ} (DCIS) lesions are non-invasive tumours of the breast which are thought to precede most invasive breast cancers (IBC). As individual DCIS lesions are initiated, grow and invade (i.e. become IBC) the size distribution of ... More
A Mathematical Framework Exhibiting the Emergence of Dynamic Expansion of Task Repertoire in \emph{Pheidole dentata}Nov 18 2015Apr 14 2016The division of labor (DOL) and task allocation among groups of ants living in a colony is thought to be highly efficient, and key to the robust survival of a colony. A great deal of experimental and theoretical work has been done toward gaining a clear ... More
Kinematic Masses of Super Star Clusters in M82 from High-Resolution Near-Infrared SpectroscopyJun 18 2003Using high-resolution (R~22,000) near-infrared (1.51 -- 1.75 microns) spectra from Keck Observatory, we measure the kinematic masses of two super star clusters in M82. Cross-correlation of the spectra with template spectra of cool evolved stars gives ... More
Experimental investigation of circular Bragg phenomenon exhibited by a mirror-backed chiral sculptured thin filmSep 08 2015Dec 09 2015Experimentation with obliquely incident light established that all four circular reflectances of a chiral sculptured thin film backed by a metallic mirror contain strong evidence of the circular Bragg phenomenon. When the mirror is removed, strong evidence ... More
Interpreting Dark Matter Direct Detection Independently of the Local Velocity and Density DistributionNov 08 2010We demonstrate precisely what particle physics information can be extracted from a single direct detection observation of dark matter while making absolutely no assumptions about the local velocity distribution and local density of dark matter. Our central ... More
Multi-wavelength Radio Continuum Emission Studies of Dust-free Red GiantsSep 03 2013Multi-wavelength centimeter continuum observations of non-dusty, non-pulsating K spectral-type red giants directly sample their chromospheres and wind acceleration zones. Such stars are feeble emitters at these wavelengths however, and previous observations ... More
Basic Experiment Planning via Information Metrics: the RoboMendel ProblemOct 17 2012In this paper we outline some mathematical questions that emerge from trying to "turn the scientific method into math". Specifically, we consider the problem of experiment planning (choosing the best experiment to do next) in explicit probabilistic and ... More
On H-Spaces and a Congruence of Catalan NumbersDec 12 2016Jul 09 2017For $p$ an odd prime and $F$ the cyclic group of order $p$, we show that the number of conjugacy classes of embeddings of $F$ in $SU(p)$ such that no element of $F$ has 1 as an eigenvalue is $(1+C_{p-1})/p$, where $C_{p-1}$ is a Catalan number. We prove ... More
Derived Koszul duality and TQ-homology completion of structured ring spectraFeb 24 2015Jul 23 2015Working in the context of symmetric spectra, we consider any higher algebraic structures that can be described as algebras over an operad O. We prove that the fundamental adjunction comparing O-algebra spectra with coalgebra spectra over the associated ... More
Damage Spreading During Domain GrowthApr 07 1994We study damage spreading in models of two-dimensional systems undergoing first order phase transitions. We consider several models from the same non-conserved order parameter universality class, and find unexpected differences between them. An exact ... More
Ultracold bosons in lattices with binary disorderJan 15 2008Jun 27 2008Quantum phases of ultracold bosons with repulsive interactions in lattices in the presence of quenched disorder are investigated. The disorder is assumed to be caused by the interaction of the bosons with impurity atoms having a large effective mass. ... More
Braid moves in commutation classes of the symmetric groupJul 02 2015Nov 01 2016We prove that the expected number of braid moves in the commutation class of the reduced word $(s_1 s_2 \cdots s_{n-1})(s_1 s_2 \cdots s_{n-2}) \cdots (s_1 s_2)(s_1)$ for the long element in the symmetric group $\mathfrak{S}_n$ is one. This is a variant ... More
A Sample of Field EllipticalsNov 27 2003Using well-defined selection criteria applied to the LEDA galaxy catalogue we have constructed a sample of elliptical galaxies that can be taken to lie in the field. Such criteria can easily be applied to theoretical simulations for direct comparison ... More
The Secret Lives of Cepheids: Evolutionary Changes and Pulsation-Induced Shock Heating in the Prototype Classical Cepheid δ CepSep 30 2014Over the past decade, the Secret Lives of Cepheids (SLiC) program has been carried out at Villanova University to study aspects and behaviors of classical Cepheids that are still not well-understood. In this, the first of several planned papers on program ... More
Investigating a Possible Spectral Signature of the Wind-ISM Interaction Region of Alpha TauSep 04 2002Ultraviolet spectra from the GHRS instrument on board the Hubble Space Telescope reveal the presence of a mysterious absorption feature in the Mg II h & k lines of the nearby (d=20.0 pc) K5 III star Alpha Tau. The narrow absorption looks like an interstellar ... More
A Game-Centered, Interactive Approach for Using Programming Exercises in Introductory PhysicsJan 07 2017Jun 01 2017Incorporating computer programming exercises in introductory physics is a delicate task that involves a number of choices that may have a strong affect on student learning. We present an approach that speaks to a number of common concerns that arise when ... More
Collapses and Revivals of Collective Excitations in Trapped Bose CondensatesDec 06 1996Sep 05 1997We present a quantum theory of low-lying excitations in a trapped Bose condensate with finite particle numbers. We find that even at zero temperature condensate number fluctuations and/or fluctuations of the excitation frequency due to quantum uncertainties ... More
Energy loss of atoms at metal surfaces due to electron-hole pair excitations: First-principles theory of "chemicurrents"Sep 30 2009A method is presented for calculating electron-hole pair excitation due to an incident atom or molecule interacting with a metal surface. Energy loss is described using an \textit{ab initio} approach that obtains a position-dependent friction coefficient ... More
Symmetric Function Theory at the Border of A_n and C_nSep 10 2018We relate the type $A_n$ and type $C_n$ Stanley symmetric functions, by producing a new symmetric function: Our double Stanley symmetric function gives the type $A$ case at $(\mathbf{x},\mathbf{0})$ and gives the type $C$ case at $(\mathbf{x},\mathbf{x})$ ... More