Results for "Brian J. LeRoy"

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Graphene on Hexagonal Boron NitrideJan 21 2014May 06 2014The field of graphene research has developed rapidly since its first isolation by mechanical exfoliation in 2004. Due to the relativistic Dirac nature of its charge carriers, graphene is both a promising material for next-generation electronic devices ... More
Local Spectroscopy of the Electrically Tunable Band Gap in Trilayer GrapheneJan 11 2013Apr 08 2013The stacking order degree of freedom in trilayer graphene plays a critical role in determining the existence of an electric field tunable band gap. We present spatially-resolved tunneling spectroscopy measurements of dual gated Bernal (ABA) and rhombohedral ... More
Scanning gate microscopy of ultra clean carbon nanotube quantum dotsAug 22 2015We perform scanning gate microscopy on individual suspended carbon nanotube quantum dots. The size and position of the quantum dots can be visually identified from the concentric high conductance rings. For the ultra clean devices used in this study, ... More
Long wavelength local density of states oscillations near graphene step edgesNov 10 2011Using scanning tunneling microscopy and spectroscopy, we have studied the local density of states (LDOS) of graphene over step edges in boron nitride. Long wavelength oscillations in the LDOS are observed with maxima parallel to the step edge. Their wavelength ... More
Evolution of the electronic band structure of twisted bilayer graphene upon dopingApr 30 2015The electronic band structure of twisted bilayer graphene depends on the twist angle between the two layers. In particular, van Hove singularities occur in the density of states when the two sets of monolayer bands cross. An enhanced Raman G peak is observed ... More
Response of graphene to femtosecond high-intensity laser irradiationMay 05 2011We study the response of graphene to high-intensity 10^11-10^12 Wcm^-2, 50-femtosecond laser pulse excitation. We establish that graphene has a fairly high (~3\times10^12Wcm^-2) single-shot damage threshold. Above this threshold, a single laser pulse ... More
Optical thickness determination of hexagonal Boron Nitride flakesMar 13 2013Mar 20 2013Optical reflectivity contrast provides a simple, fast and noninvasive method for characterization of few monolayer samples of two-dimensional materials. Here we apply this technique to measure the thickness of thin flakes of hexagonal Boron Nitride (hBN), ... More
Pressure-induced commensurate stacking of graphene on boron nitrideMar 10 2016Combining atomically-thin van der Waals (vdW) materials into heterostructures provides a powerful path towards the creation of designer electronic devices. Interactions between the individual atomic layers of the heterostructure strongly affect the properties ... More
Optical characterization of electron-phonon interactions at the saddle point in grapheneOct 10 2013The role of electron-phonon interactions is experimentally and theoretically investigated near the saddle point absorption peak of graphene. The differential optical transmission spectra of multiple, non-interacting layers of graphene reveals the dominant ... More
Ore extensions satisfying a polynomial identityJul 02 2007Necessary and sufficient conditions for an Ore extension $S=R[x;\si,\de]$ to be a {\rm PI} ring are given in the case $\si$ is an injective endomorphism of a semiprime ring $R$ satisfying the {\rm ACC} on annihilators. Also, for an arbitrary endomorphism ... More
Noncommutative symmetric functions and W-polynomialsJun 24 2006Let K,S,D be a division ring, an endomorphism and a S-derivation of K, respectively. In this setting we introduce generalized noncommutative symmetric functions and obtain Vieta formula and decompositions of differential operators. W-polynomials show ... More
Intrinsic disorder in graphene on transition metal dichalcogenide heterostructuresNov 24 2014The electronic properties of two-dimensional materials such as graphene are extremely sensitive to their environment, especially the underlying substrate. Planar van der Waals bonded substrates such as hexagonal boron nitride (hBN) have been shown to ... More
Band Structure Mapping of Bilayer Graphene via Quasiparticle ScatteringJun 03 2014A perpendicular electric field breaks the layer symmetry of Bernal-stacked bilayer graphene, resulting in the opening of a band gap and a modification of the effective mass of the charge carriers. Using scanning tunneling microscopy and spectroscopy, ... More
Electric Field Control of Soliton Motion and Stacking in Trilayer GrapheneJan 29 2014The crystal structure of a material plays an important role in determining its electronic properties. Changing from one crystal structure to another involves a phase transition which is usually controlled by a state variable such as temperature or pressure. ... More
Emergence of Topologically Protected Helical States in Minimally Twisted Bilayer GrapheneFeb 08 2018Bilayer graphene samples in which inversion symmetry is broken have quantum valley Hall ground states that support counterpropogating topologically protected helical (TPH) edge states localized along domain walls between AB and BA stacking regions. Moreover, ... More
Emergence of Superlattice Dirac Points in Graphene on Hexagonal Boron NitrideFeb 13 2012The Schr\"odinger equation dictates that the propagation of nearly free electrons through a weak periodic potential results in the opening of band gaps near points of the reciprocal lattice known as Brillouin zone boundaries. However, in the case of massless ... More
Compilation of extended recursion in call-by-value functional languagesFeb 07 2009This paper formalizes and proves correct a compilation scheme for mutually-recursive definitions in call-by-value functional languages. This scheme supports a wider range of recursive definitions than previous methods. We formalize our technique as a ... More
Compact convolutionMay 17 2006We state a Yoneda-type lemma which leads to various functor categories being compact closed.
Beyond the Standard Model: LHC Phenomenology, Cosmology from Post-Inflationary Sources, and Dark Matter PhysicsAug 24 2013It is the goal of this dissertation to demonstrate that beyond the standard model, certain theories exist which solve conflicts between observation and theory -- conflicts such as massive neutrinos, dark matter, unstable Higgs vacuum, and recent Planck ... More
The mean-square of Dirichlet L-functionsAug 20 2007We verify the conjecture of [CFKRS] for the mean square near the critical point of Dirichlet L-functions for a composite modulus q. We also prove a kind of reciprocity formula when the second moment for a prime modulus is twisted by a character evaluated ... More
Einstein's Equations for Spin $2$ Mass $0$ from Noether's Converse Hilbertian AssertionOct 17 2016An overlap between the general relativist and particle physicist views of Einstein gravity is uncovered. Noether's 1918 paper developed Hilbert's and Klein's reflections on the conservation laws. Energy-momentum is just a term proportional to the field ... More
Electrical generation and absorption of phonons in carbon nanotubesJan 21 2005The interplay between discrete vibrational and electronic degrees of freedom directly influences the chemical and physical properties of molecular systems. This coupling is typically studied through optical methods such as fluorescence, absorption, and ... More
Integration of a gate electrode into carbon nanotube devices for scanning tunneling microscopyFeb 21 2005We have developed a fabrication process for incorporating a gate electrode into suspended single-walled carbon nanotube structures for scanning tunneling spectroscopy studies. The nanotubes are synthesized by chemical vapor deposition directly on a metal ... More
Scanning Tunneling Spectroscopy of Suspended Single-Wall Carbon NanotubesMar 12 2004We have performed low-temperature STM measurements on single-wall carbon nanotubes that are freely suspended over a trench. The nanotubes were grown by CVD on a Pt substrate with predefined trenches etched into it. Atomic resolution was obtained on the ... More
The cubic moment of central values of automorphic L-functionsOct 22 1998May 01 2000The authors study the central values of L-functions in certain families; in particular they bound the sum of the cubes of these values.Contents:
On the Selberg class of Dirichlet series: small weightsApr 01 1992In the study of Dirichlet series with arithmetic significance there has appeared (through the study of known examples) certain expectations, namely (i) if a functional equation and Euler product exists, then it is likely that a type of Riemann hypothesis ... More
Spacing of zeros of Hecke L-functions and the class number problemNov 01 2001We derive strong and effective lower bounds for the class number h(q) of the imaginary quadratic field Q(\sqrt{-q}), conditionally subject to the existence of many small (subnormal) gaps between zeros of the L-function associated with a character of the ... More
A Supergiant Supernova-Blown Bubble in the Spiral Galaxy NGC 1620Dec 06 1994We present UBR and H$\alpha$ imaging of NGC 1620, a highly inclined spiral galaxy that contains a large scale, arc-like feature of radius 3 kpc in its outer disk at a distance of $\sim$ 11 kpc from the center. What is unusual about this arc-like feature ... More
Strong [O III] and [N II] emission lines in globular clusters from photoionized R Corona Borealis star windsOct 28 2010The globular cluster X-ray source CXO J033831.8-352604 in NGC 1399 has recently been found to show strong emission lines of [O III] and [N II] in its optical spectrum in addition to ultraluminous X-ray emission with a soft X-ray spectrum. It was further ... More
A conjecture for the sixth power moment of the Riemann zeta-functionJul 02 1998The authors conjecture an asymptotic expression for the sixth power moment of the Riemann zeta function. They establish related results on the asymptotics of the zeta function that support the conjecture.
Lognormal properties of SGR 1806-20 and the Possibility of a Quiescent Population of other SGR sourcesJul 21 1998Monte Carlo simulations of long SGR event sequences based on lognormal distributions with a range of time intervals and intensity distribution parameters have been investigated. The main conclusions are that the majority of SGRs with properties similar ... More
Local Spectroscopic Characterization of Spin and Layer Polarization in WSe$_2$May 01 2015Jul 29 2015We report scanning tunneling microscopy (STM) and spectroscopy (STS) measurements of monolayer and bilayer WSe$_2$. We measure a band gap of 2.21 $\pm$ 0.08 eV in monolayer WSe$_2$, which is much larger than the energy of the photoluminescence peak indicating ... More
Coauthorship and citation in scientific publishingApr 01 2013A large number of published studies have examined the properties of either networks of citation among scientific papers or networks of coauthorship among scientists. Here, using an extensive data set covering more than a century of physics papers published ... More
An efficient and principled method for detecting communities in networksApr 18 2011A fundamental problem in the analysis of network data is the detection of network communities, groups of densely interconnected nodes, which may be overlapping or disjoint. Here we describe a method for finding overlapping communities based on a principled ... More
No Escape from the Supernova! Magnetic Imprisonment of Dusty Pinballs by a Supernova RemnantJan 21 2018Motivated by recent measurements of deposits of $^{60}$Fe on the ocean floor and the lunar surface, we model the transport of dust grains containing $^{60}$Fe from a near-Earth (i.e., within 100 pc) supernova (SN). We inject dust grains into the environment ... More
Radioactive Iron Rain: Transporting $^{60}$Fe in Supernova Dust to the Ocean FloorApr 04 2016Jun 07 2016Several searches have found evidence of $^{60}$Fe deposition, presumably from a near-Earth supernova (SN), with concentrations that vary in different locations on Earth. This paper examines various influences on the path of interstellar dust carrying ... More
Astrophysical Shrapnel: Discriminating Among Near-Earth Stellar Explosion Sources of Live Radioactive IsotopesMay 16 2014Mar 09 2015We consider the production and deposition on Earth of isotopes with half-lives in the range 10$^{5}$ to 10$^{8}$ years that might provide signatures of nearby stellar explosions, extending previous analyses of Core-Collapse Supernovae (CCSNe) to include ... More
Testing Landau gauge OPE on the Lattice with a $<A^2>$ CondensateJan 26 2001Jan 27 2001Using the operator product expansion we show that the $O(1/p^2)$ correction to the perturbative expressions for the gluon propagator and the strong coupling constant resulting from lattice simulations in the Landau gauge are due to a non-vanishing vacuum ... More
Asymptotic behaviour of the gluon propagator from lattice QCDMar 16 1999Feb 15 2001We study the flavorless gluon propagator in the Landau gauge from high statistics lattice calculations. Hypercubic artifacts are efficiently eliminated by taking the $\sum p_\mu^4 \to 0$ limit. The propagator is fitted to the three-loops perturbative ... More
Asymptotic scaling of the gluon propagtor on the latticeOct 01 1999We pursue the study of the high energy behaviour of the gluon propagator on the lattice in the Landau gauge in the flavorless case (n_f=0). It was shown in a precedin g paper that the gluon propagator did not reach three-loop asymptotic scaling at an ... More
Preliminaries on a Lattice Analysis of The Pion Light-cone Wave function: a Partonic Signal?May 22 2001We present the first attempt of a new method to compute the pion light-cone wave function (LCWF) on the lattice. We compute the matrix element between the pion and the vacuum of a non-local operator: the propagator of a ``scalar quark'' (named for short ... More
An $S$-adic characterization of minimal subshifts with first difference of complexity $1 \leq p(n+1) - p(n) \leq 2$May 02 2013In [Ergodic Theory Dynam. System, 16 (1996) 663--682], S. Ferenczi proved that any minimal subshift with first difference of complexity bounded by 2 is $S$-adic with $\card S \leq 3^{27}$. In this paper, we improve this result by giving an $S$-adic charaterization ... More
Noncommutative polynomial mapsAug 01 2012Polynomial maps attached to polynomials of an Ore extension are naturally defi ned. In this setting we show the importance of pseudo-linear transformations and give some applications. In particular, factorizations of polynomials in an Ore extension over ... More
mu-Squared Dependent Deviation of the Non Perturbative ZA,MOM from the True Axial Renormalisation Constant, Implied by Ward IdentityMar 31 2015Apr 02 2015It is recalled why, as already stated in a previous paper, there seems to be an inconsistency in identifying the non perturbative ZA,MOM as the renormalisation of the axial current, or equivalently, in setting as normalisation condition that the renormalised ... More
Consistent OPE Description of Gluon Two- and Three-point Green Function?Aug 04 2000Aug 07 2000We perform an OPE analysis of the flavorless non-perturbative gluon propagator and the symmetric three-gluon vertex in the Landau gauge. The first subdominant operator is $A_\mu A^\mu$ which can condensate in the Landau gauge ``vacuum'' although being ... More
Stochastic Structural Stability Theory applied to roll/streak formation in boundary layer shear flowNov 05 2010Stochastic Structural Stability Theory (SSST) provides an autonomous, deterministic, nonlinear dynamical system for evolving the statistical mean state of a turbulent system. In this work SSST is applied to the problem of understanding the formation of ... More
Equilibrium and Stability of Polarization in Ultrathin Ferroelectric Films with Ionic Surface CompensationDec 31 2010Jul 30 2011Thermodynamic theory is developed for the ferroelectric phase transition of an ultrathin film in equilibrium with a chemical environment that supplies ionic species to compensate its surface. Equations of state and free energy expressions are developed ... More
Radiation hardness studies of InGaAs and Si photodiodes at 30, 52, & 98 MeV and fluences to 5x10^11 protons/cm^2Jun 13 2011Oct 04 2012Here we report the results of an investigation into the effects of ionizing radiation on commercial-off-the-shelf InGaAs and Si photodiodes. The photodiodes were exposed to 30, 52, and 98 MeV protons with fluences ranging from 10^8 - 5x10^11 protons/cm^2 ... More
Universally Coupled Massive GravityMar 11 2005Jul 14 2007We derive Einstein's equations from a linear theory in flat space-time using free-field gauge invariance and universal coupling. The gravitational potential can be either covariant or contravariant and of almost any density weight. We adapt these results ... More
A Compact Circumstellar Shell as the Source of High--velocity Features in SN 2011feMay 19 2015High--velocity features (HVF), especially of Ca II, are frequently seen in Type Ia supernovae observed prior to B-band maximum (Bmax). These HVF start at more than 25,000 km/s in the days after first light, and slow to about 18,000 km/s near Bmax. To ... More
Interlayer Transport in Disordered Semiconductor Electron BilayersJan 31 2012We study the effects of disorder on the interlayer transport properties of disordered semiconductor bilayers outside of the quantum Hall regime by performing self-consistent quantum transport calculations. We find that the addition of material disorder ... More
Random graph models for directed acyclic networksJul 24 2009We study random graph models for directed acyclic graphs, an important class of networks that includes citation networks, food webs, and feed-forward neural networks among others. We propose two specific models, roughly analogous to the fixed edge number ... More
Random graphs containing arbitrary distributions of subgraphsMay 10 2010Traditional random graph models of networks generate networks that are locally tree-like, meaning that all local neighborhoods take the form of trees. In this respect such models are highly unrealistic, most real networks having strongly non-tree-like ... More
Equivariant Dimensional Reduction and Quiver Gauge TheoriesJan 14 2010We review recent applications of equivariant dimensional reduction techniques to the construction of Yang-Mills-Higgs-Dirac theories with dynamical mass generation and exactly massless chiral fermions.
Solitons and Yukawa Couplings in Nearly Kahler Flux CompactificationsAug 05 2012Aug 18 2013We study vacuum states and symmetric fermions in equivariant dimensional reduction of Yang-Mills-Dirac theory over the six-dimensional homogeneous space SU(3)/U(1)x U(1) endowed with a family of SU(3)-structures including a nearly Kahler structure. We ... More
Coherent states on spheresSep 18 2001Nov 26 2001We describe a family of coherent states and an associated resolution of the identity for a quantum particle whose classical configuration space is the d-dimensional sphere S^d. The coherent states are labeled by points in the associated phase space T*(S^d). ... More
Magnetic characterization of the frustrated three-leg ladder compound [(CuCl2tachH)3Cl]Cl2Mar 22 2004Aug 11 2004We report the magnetic features of a new one-dimensional stack of antiferromagnetically coupled equilateral copper(II) triangles. High-field magnetization measurements show that the interaction between the copper triangles is of the same order of magnitude ... More
On the leading OPE corrections to the ghost-gluon vertex and the Taylor theoremSep 17 2011Jan 19 2012This brief note is devoted to a study of genuine non-perturbative corrections to the Landau gauge ghost-gluon vertex in terms of the non-vanishing dimension-two gluon condensate. We pay special attention to the kinematical limit which the bare vertex ... More
Lattice calculation of $α_s$ in momentum schemeOct 12 1998Oct 26 1998We compute the flavorless running coupling constant of QCD from the three gluon vertex in the (regularisation independent) momentum subtraction renormalisation scheme. This is performed on the lattice with high statistics. The expected color dependence ... More
High moments of the Riemann zeta-functionFeb 01 1999The authors describe a general approach which, in principal, should produce the correct (conjectural) formula for every even integer moment of the Riemann zeta function. They carry it out for the sixth and eigth powers; in the case of sixth powers this ... More
Proof of a Conjecture of Z.-W. Sun on Trigonometric SeriesJun 27 2016Recently, Z. W. Sun introduced a sequence $(S_n)_{n\geq 0}$, where $S_n=\frac{\binom{6n}{3n} \binom{3n}{n}}{2(2n+1)\binom{2n}{n}}$, and found one congruence and two convergent series on $S_n$ by {\tt{Mathematica}}. Furthermore, he proposed some related ... More
SOFIA Observations of SN 2010jl: Another Non-Detection of the 9.7 $μ$m Silicate Dust FeatureJun 30 2015We present photometric observations from the {\it Stratospheric Observatory for Infrared Astronomy (SOFIA)} at 11.1 $\mu$m of the Type IIn supernova (SN IIn) 2010jl. The SN is undetected by {\it SOFIA}, but the upper limits obtained, combined with new ... More
The Segal-Bargmann transform for compact quotients of symmetric spaces of the complex typeSep 28 2007Sep 29 2010Let G/K be a Riemannian symmetric space of the complex type, meaning that G is complex semisimple and K is a compact real form. Now let {\Gamma} be a discrete subgroup of G that acts freely and cocompactly on G/K. We consider the Segal--Bargmann transform, ... More
A message passing approach for general epidemic modelsMar 29 2010Jul 22 2010In most models of the spread of disease over contact networks it is assumed that the probabilities per unit time of disease transmission and recovery from disease are constant, implying exponential distributions of the time intervals for transmission ... More
Some Koszul properties of standard and irreducible modulesMay 27 2013Let $G$ be a simple, simply connected algebraic group over an algebraically closed field of positive characteristic $p$. In recent work, the authors have studied a graded analogue of the category of rational $G$-modules. These gradings are not natural ... More
Photon wave functions, wave-packet quantization of light, and coherence theoryAug 06 2007Dec 09 2007The monochromatic Dirac and polychromatic Titulaer-Glauber quantized field theories (QFTs) of electromagnetism are derived from a photon-energy wave function in much the same way that one derives QFT for electrons, that is, by quantization of a single-particle ... More
The Maxwell wave function of the photonApr 24 2006James Clerk Maxwell unknowingly discovered a correct relativistic, quantum theory for the light quantum, forty-three years before Einstein postulated the photon's existence. In this theory, the usual Maxwell field is the quantum wave function for a single ... More
Landscape Predictions for the Higgs Boson and Top Quark MassesAug 11 2006Jul 31 2007If the Standard Model is valid up to scales near the Planck mass, and if the cosmological constant and Higgs mass parameters scan on a landscape of vacua, it is well known that the observed orders of magnitude of these quantities can be understood from ... More
The Pion Light-Cone Wave Function Phi_pi on the lattice: a partonic signal?Oct 22 2001We determine the conditions required to study the pion light-cone wave function Phi_pi with a new method: a direct display of the partons constituting the pion. We present the preliminary results of a lattice computation of Phi_pi following this direction. ... More
The Conformal Sector of F-theory GUTsMar 16 2011Mar 06 2012D3-brane probes of exceptional Yukawa points in F-theory GUTs are natural hidden sectors for particle phenomenology. We find that coupling the probe to the MSSM yields a new class of N = 1 conformal fixed points with computable infrared R-charges. Quite ... More
Dimensional Reduction and Vacuum Structure of Quiver Gauge TheoryMay 29 2009Nov 02 2011We describe the structure of the vacuum states of quiver gauge theories obtained via dimensional reduction over homogeneous spaces, in the explicit example of SU(3)-equivariant dimensional reduction of Yang-Mills-Dirac theory on manifolds of the form ... More
Coherent states for a 2-sphere with a magnetic fieldDec 06 2011Jan 19 2012We consider a particle moving on a 2-sphere in the presence of a constant magnetic field. Building on earlier work in the nonmagnetic case, we construct coherent states for this system. The coherent states are labeled by points in the associated phase ... More
The large radius limit for coherent states on spheresMar 28 2002Apr 27 2002This paper concerns the coherent states on spheres studied by the authors in [J. Math. Phys. 43 (2002), 1211-1236]. We show that in the odd-dimensional case the coherent states on the sphere approach the classical Gaussian coherent states on Euclidean ... More
Competing epidemics on complex networksMay 17 2011Human diseases spread over networks of contacts between individuals and a substantial body of recent research has focused on the dynamics of the spreading process. Here we examine a model of two competing diseases spreading over the same network at the ... More
Two-photon wave mechanicsMay 17 2006Feb 21 2007The position-representation wave function for multi-photon states and its equation of motion are introduced. A major strength of the theory is that it describes the complete evolution (including polarization and entanglement) of multi-photon states propagating ... More
Simultaneous Solutions of the Strong CP and Mu ProblemsNov 01 2004Nov 11 2004The \mu parameter of the supersymmetric standard model is replaced by \lambda S, where S is a singlet chiral superfield, introducing a Peccei--Quinn symmetry into the theory. Dynamics at the electroweak scale naturally solves both the strong CP and \mu ... More
Density Perturbations and the Cosmological Constant from Inflationary LandscapesJun 27 2005An anthropic understanding of the cosmological constant requires that the vacuum energy at late time scans from one patch of the universe to another. If the vacuum energy during inflation also scans, the various patches of the universe acquire exponentially ... More
Log-behavior of two sequences related to the elliptic integralsFeb 13 2016Aug 01 2016Two interesting sequences arose in the study of the series expansions of the complete elliptic integrals, which are called the Catalan-Larcombe-French sequence $\{P_n\}_{n\geq 0}$ and the Fennessey-Larcombe-French sequence $\{V_n\}_{n\geq 0}$ respectively. ... More
Quantum state estimation with unknown measurementsJun 27 2013Mar 03 2014Improved measurement techniques are central to technological development and foundational scientific exploration. Quantum optics relies upon detectors sensitive to non-classical features of light, enabling precise tests of physical laws and quantum-enhanced ... More
Preliminary Calculation of $α_s$ from Green Functions with Dynamical QuarksJul 26 2001Oct 16 2001We present preliminary results on the computation of the QCD running coupling constant in the $\widetilde{MOM}$ scheme and Landau gauge with two flavours of dynamical Wilson quarks. Gluon momenta range up to about 7 GeV ($\beta =$ 5.6, 5.8 and 6.0) with ... More
The Infrared Behaviour of the Pure Yang-Mills Green FunctionsSep 09 2011Jan 19 2012We review the infrared properties of the pure Yang-Mills correlators and discuss recent results concerning the two classes of low-momentum solutions for them reported in literature; i.e. decoupling and scaling solutions. We will mainly focuss on the Landau ... More
Universal power law governing pedestrian interactionsDec 02 2014Human crowds often bear a striking resemblance to interacting particle systems, and this has prompted many researchers to describe pedestrian dynamics in terms of interaction forces and potential energies. The correct quantitative form of this interaction, ... More
The Segal--Bargmann transform for odd-dimensional hyperbolic spacesJul 13 2015Aug 11 2015We develop isometry and inversion formulas for the Segal--Bargmann transform on odd-dimensional hyperbolic spaces that are as parallel as possible to the dual case of odd-dimensional spheres.
The Segal-Bargmann transform for noncompact symmetric spaces of the complex typeSep 17 2004Feb 01 2005We consider the generalized Segal-Bargmann transform, defined in terms of the heat operator, for a noncompact symmetric space of the complex type. For radial functions, we show that the Segal-Bargmann transform is a unitary map onto a certain L^2 space ... More
Very high efficiency photospheric emission in long duration gamma-ray burstsApr 17 2009Jun 23 2009We numerically analyze the evolution of a long-duration gamma-ray burst jet as it leaves the progenitor star and propagates to the photospheric radius, where radiation can be released. We find that the interaction of the relativistic material with the ... More
Machine Agency in Human-Machine Networks; Impacts and Trust ImplicationsFeb 26 2016We live in an emerging hyper-connected era in which people are in contact and interacting with an increasing number of other people and devices. Increasingly, modern IT systems form networks of humans and machines that interact with one another. As machines ... More
Stochastic blockmodels and community structure in networksAug 23 2010Stochastic blockmodels have been proposed as a tool for detecting community structure in networks as well as for generating synthetic networks for use as benchmarks. Most blockmodels, however, ignore variation in vertex degree, making them unsuitable ... More
Random acyclic networksFeb 23 2009Directed acyclic graphs are a fundamental class of networks that includes citation networks, food webs, and family trees, among others. Here we define a random graph model for directed acyclic graphs and give solutions for a number of the model's properties, ... More
Mean values of L-functions and symmetryDec 13 1999Recently Katz and Sarnak introduced the idea of a symmetry group attached to a family of L-functions, and they gave strong evidence that the symmetry group governs many properties of the distribution of zeros of the L-functions. We consider the mean-values ... More
Solar irradiance changes and phytoplankton productivity in Earth's ocean following astrophysical ionizing radiation eventsApr 06 2016Two atmospheric responses to simulated astrophysical ionizing radiation events significant to life on Earth are production of odd-nitrogen species, especially NO2, and subsequent depletion of stratospheric ozone. Ozone depletion increases incident short-wavelength ... More
High-stability time-domain balanced homodyne detector for ultrafast optical pulse applicationsDec 05 2011Mar 25 2013Low-noise, efficient, phase-sensitive time-domain optical detection is essential for foundational tests of quantum physics based on optical quantum states and the realization of numerous applications ranging from quantum key distribution to coherent classical ... More
Dimensional Reduction, Monopoles and Dynamical Symmetry BreakingJan 16 2009Mar 05 2009We consider SU(2)-equivariant dimensional reduction of Yang-Mills-Dirac theory on manifolds of the form M x CP(1), with emphasis on the effects of non-trivial magnetic flux on CP(1). The reduction of Yang-Mills fields gives a chain of coupled Yang-Mills-Higgs ... More
Actually, It's About Ethics in Computational Social Science: A Multi-party Risk-Benefit Framework for Online Community ResearchNov 20 2015Managers regularly face a complex ethical dilemma over how to best govern online communities by evaluating the effectiveness of different social or technical strategies. What ethical considerations should guide researchers and managers when they employ ... More
Isometry theorem for the Segal-Bargmann transform on noncompact symmetric spaces of the complex typeJul 05 2007Aug 01 2007We consider the Segal-Bargmann transform for a noncompact symmetric space of the complex type. We establish isometry and surjectivity theorems for the transform, in a form as parallel as possible to the results in the compact case. The isometry theorem ... More
Friendship networks and social statusMay 30 2012In empirical studies of friendship networks participants are typically asked, in interviews or questionnaires, to identify some or all of their close friends, resulting in a directed network in which friendships can, and often do, run in only one direction ... More
New graded methods in the homological algebra of semisimple algebraic groupsApr 04 2013Dec 17 2013Let $G$ be a semisimple algebraic group over an algebraically closed field $k$ of positive characteristic $p$. Under some restrictions on the size of $p$, the present paper establishes new results on the $G$-module structure of $\Ext^\bullet_{G_1}(V,W)$ ... More
First MINOS Results with the NuMI BeamJan 26 2007The results from the initial exposure of the MINOS detectors to neutrinos produced by the Fermilab NuMI beam are reported here. The exposure consisted of 1.27 x 10^{20} 120 GeV protons incident on the NuMI target. The data show the observation of 215 ... More
A Rigourous Treatment of the Lattice Renormalization Problem of F_BAug 05 1992The $B$-meson decay constant can be measured on the lattice using a $1/m_b$ expansion. To relate the physical quantity to Monte Carlo data one has to know the renormalization coefficient, $Z$, between the lattice operators and their continuum counterparts. ... More
Nuclear models on a latticeNov 04 2005We present the first results of a quantum field approach to nuclear models obtained by lattice techniques. Renormalization effects for fermion mass and coupling constant in case of scalar and pseudoscalar interaction lagrangian densities are discussed. ... More
Three-loop beta function and non-perturbative $α_s$ in asymmetric momentum schemeOct 21 1998Jan 05 1999We determine the three-loop coefficient of the beta function in the asymmetric momentum subtraction scheme in Landau gauge. This scheme is convenient for lattice studies of \alpha_s, the running coupling constant of QCD. We present high statistics lattice ... More