Results for "J. Patrick Harding"

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Comment on "Joint Anisotropy and Source Count Constraints on the Contribution of Blazars to the Diffuse Gamma-Ray Background"Apr 17 2012We show the conclusions claimed in the manuscript arXiv:1202.5309v1 by Cuoco, Komatsu and Siegal-Gaskins (CKS) are not generally valid. The results in CKS are based on a number of simplifying assumptions regarding the source population below the detection ... More
Models of the Contribution of Blazars to the Anisotropy of the Extragalactic Diffuse Gamma-ray BackgroundJun 20 2012Oct 30 2012We study the relation between the measured anisotropies in the extragalactic diffuse gamma-ray background (DGRB) and the DGRB spectral intensity, and their potential origin from the unresolved blazar population. Using a physical-evolution model for blazars ... More
Constraints on WIMP and Sommerfeld-Enhanced Dark Matter Annihilation from HESS Observations of the Galactic CenterOct 27 2011Jan 03 2012We examine the constraints on models of weakly interacting massive particle (WIMP) dark matter from the recent observations of the Galactic center by the High Energy Spectroscopic System (HESS) telescope. We analyze canonical WIMP annihilation into Standard ... More
Morphological Tests of the Pulsar and Dark Matter Interpretations of the WMAP HazeOct 26 2009Dec 15 2009The WMAP haze is an excess in microwave emission coming from the center of the Milky Way galaxy. In the case of synchrotron emission models of the haze, we present tests for the source of radiating high-energy electrons/positrons. We explore several models ... More
Novel Gamma-Ray Signatures of PeV-Scale Dark MatterDec 07 2017The gamma-ray annihilation and decay products of very heavy dark matter particles can undergo attenuation through pair production, leading to the development of electromagnetic cascades. This has a significant impact not only on the spectral shape of ... More
Dark Matter Annihilation and Decay Searches with the High Altitude Water Cherenkov (HAWC) ObservatoryAug 18 2015In order to observe annihilation and decay of dark matter, several types of potential sources should be considered. Some sources, such as dwarf galaxies, are expected to have very low astrophysical backgrounds but fairly small dark matter densities. Other ... More
Current and Future Constraints on Dark Matter from Prompt and Inverse-Compton Photon Emission in the Isotropic Diffuse Gamma-ray BackgroundNov 23 2010Feb 08 2012We perform a detailed examination of current constraints on annihilating and decaying dark matter models from both prompt and inverse-Compton emission photons, including both model-dependent and model-independent bounds. We also show that the observed ... More
The Contribution of Blazars to the Extragalactic Diffuse Gamma-ray Background and Their Future Spatial ResolutionDec 06 2010Nov 15 2011We examine the constraints on the luminosity-dependent density evolution model for the evolution of blazars given the observed spectrum of the diffuse gamma-ray background (DGRB), blazar source-count distribution, and the blazar spectral energy distribution ... More
Stellar Populations in the Outer Disk and Halo of the Spiral Galaxy M101Jun 18 2018We use deep Hubble Space Telescope imaging in the outskirts of the nearby spiral M101 to study stellar populations in the galaxy's outer disk and halo. Our ACS field lies 17.6 arcmin (36 kpc) from the center of M101 and targets the blue "NE Plume" of ... More
First Limits on the Dark Matter Cross Section with the HAWC ObservatoryAug 18 2015Oct 30 2015The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field-of-view observatory sensitive to 100 GeV - 100 TeV gamma rays and cosmic rays. The HAWC observatory is also sensitive to diverse indirect searches for dark matter annihilation, ... More
Looking Under a Better Lamppost: MeV-scale Dark Matter CandidatesMar 14 2019The era of precision cosmology has revealed that about 85% of the matter in the universe is dark matter. Two well-motivated candidates are weakly interacting massive particles (WIMPs) and weakly interacting sub-eV particles (WISPs) (e.g. axions). Both ... More
A high-level analysis framework for HAWCAug 29 2015The High Altitude Water Cherenkov (HAWC) Observatory continuously observes gamma-rays between 100 GeV to 100 TeV in an instantaneous field of view of about 2 steradians above the array. The large amount of raw data, the importance of small number statistics, ... More
The Multi-Mission Maximum Likelihood framework (3ML)Jul 29 2015Astrophysical sources are now observed by many different instruments at different wavelengths, from radio to high-energy gamma-rays, with an unprecedented quality. Putting all these data together to form a coherent view, however, is a very difficult task. ... More
On the methods of determining the radio emission geometry in pulsar magnetospheresJul 11 2003Feb 21 2004We present a modification of the relativistic phase shift method of determining the radio emission geometry from pulsar magnetospheres proposed by Gangadhara & Gupta (2001). Our modification provides a method of determining radio emission altitudes which ... More
Prediction and Mitigation of Crush Conditions in Emergency EvacuationsMay 03 2008Several simulation environments exist for the simulation of large-scale evacuations of buildings, ships, or other enclosed spaces. These offer sophisticated tools for the study of human behaviour, the recreation of environmental factors such as fire or ... More
Polarization of pulsar radiation in the two-pole caustic model and in the outer gap modelMar 17 2004We present linear polarization characteristics of pulsar radiation as predicted by two models of high-energy radiation from extended regions in the outer magnetosphere: the recently proposed two-pole caustic model, and the outer gap model.
Relativistic effects and polarization in three high-energy pulsar modelsJan 13 2004We present the influence of the special relativistic effects of aberration and light travel time delay on pulsar high-energy lightcurves and polarization characteristics predicted by three models: the two-pole caustic model, the outer gap model, and the ... More
The FourStar Infrared CameraJul 24 2008The FourStar infrared camera is a 1.0-2.5 micron (JHKs) near infrared camera for the Magellan Baade 6.5m telescope at Las Campanas Observatory (Chile). It is being built by Carnegie Observatories and the Instrument Development Group at Johns Hopkins and ... More
Smartphone scene generator for efficient characterization of visible imaging detectorsJun 18 2018Aug 07 2018Full characterization of imaging detectors involves subjecting them to spatially and temporally varying illumination patterns over a large dynamic range. Here we present a scene generator that fulfills many of these functions. Based on a modern smartphone, ... More
Coil Creep and Skew-Quadrupole Field Components in the TevatronSep 25 2012During the first 20 years of operation, the Fermilab Tevatron developed strong coupling between the two transverse degrees of freedom. The required strength of the circuit of skew quadrupole magnets used to correct for coupling, though capable, had increased ... More
The effect of an offset-dipole magnetic field on the Vela pulsar's gamma-ray light curvesApr 26 2015Over the past six years, the Fermi Large Area Telescope has detected more than 150 gamma-ray pulsars, discovering a variety of light curve trends and classes. Such diversity hints at distinct underlying magnetospheric and/or emission geometries. We implemented ... More
What can we learn from phase alignment of gamma-ray and radio pulsar light curves?Dec 14 2011The Fermi Large Area Telescope (LAT) has revolutionized high-energy (HE) astronomy, and is making enormous contributions particularly to gamma-ray pulsar science. As a result of the many new pulsar discoveries, the gamma-ray pulsar population is now approaching ... More
Modeling Light Curves of the Phase-Aligned Gamma-ray Millisecond Pulsar SubclassNov 04 2011The gamma-ray population of millisecond pulsars (MSPs) detected by the Fermi Large Area Telescope (LAT) has been steadily increasing. A number of the more recent detections, including PSR J0034-0534, PSR J1939+2134 (B1937+21; the first MSP ever discovered), ... More
CO adsorption on neutral iridium clustersSep 27 2010The adsorption of carbon monoxide on neutral iridium clusters in the size range of n = 3 to 21 atoms is investigated with infrared multiple photon dissociation spectroscopy. For each cluster size only a single v(CO) band is present with frequencies in ... More
Implementation of an offset-dipole magnetic field in a pulsar modelling codeNov 07 2014The light curves of gamma-ray pulsars detected by the Fermi Large Area Telescope show great variety in profile shape and position relative to their radio profiles. Such diversity hints at distinct underlying magnetospheric and/or emission geometries for ... More
The Effect of Different Magnetospheric Structures on Predictions of Gamma-ray Pulsar Light CurvesJan 21 2015The second pulsar catalogue of the Fermi Large Area Telescope (LAT) will contain in excess of 100 gamma-ray pulsars. The light curves (LCs) of these pulsars exhibit a variety of shapes, and also different relative phase lags with respect to their radio ... More
Modeling and Maximum Likelihood Fitting of Gamma-Ray and Radio Light Curves of Millisecond Pulsars Detected with FermiOct 25 2011Nov 02 2011Pulsed gamma rays have been detected with the Fermi Large Area Telescope (LAT) from more than 20 millisecond pulsars (MSPs), some of which were discovered in radio observations of bright, unassociated LAT sources. We have fit the radio and gamma-ray light ... More
New Neighbours: Modelling the Growing Population of Gamma-ray Millisecond PulsarsJul 08 2010The Fermi Large Area Telescope, in collaboration with several groups from the radio community, have had marvellous success at uncovering new gamma-ray millisecond pulsars (MSPs). In fact, MSPs now make up a sizable fraction of the total number of known ... More
Identification of competing ultrafast all-optical switching mechanisms in Si woodpile photonic crystalsJul 28 2008Apr 22 2009We present a systematic study of ultrafast all-optical switching of Si photonic band gap woodpile crystals using broadband tunable nondegenerate pump-probe spectroscopy. At pump-probe coincidence, we investigate the behavior the differential reflectivity ... More
Deep Imaging of M51: a New View of the Whirlpool's Extended Tidal DebrisJan 19 2015We present deep, wide-field imaging of the M51 system using CWRU's Burrell Schmidt telescope at KPNO to study the faint tidal features that constrain its interaction history. Our images trace M51's tidal morphology down to a limiting surface brightness ... More
The Red and Featureless Outer Disks of Nearby Spiral GalaxiesMay 17 2016We present results from deep, wide-field surface photometry of three nearby (D=4--7 Mpc) spiral galaxies: M94 (NGC 4736), M64 (NGC 4826), and M106 (NGC 4258). Our imaging reaches limiting surface brightnesses of $\mu_{B} \sim$ 28 -- 30 mag arcsec$^{-2}$ ... More
Broadband sensitive pump-probe setup for ultrafast optical switching of photonic nanostructures and semiconductorsMar 01 2009We describe an ultrafast time resolved pump-probe spectroscopy setup aimed at studying the switching of nanophotonic structures. Both fs pump and probe pulses can be independently tuned over broad frequency range between 3850 and 21050 cm$^{-1}$. A broad ... More
The empirical equilibrium structure of diacetyleneFeb 28 2008High-level quantum-chemical calculations are reported at the MP2 and CCSD(T) levels of theory for the equilibrium structure and the harmonic and anharmonic force fields of diacetylene, HCCCCH. The calculations were performed employing Dunning's hierarchy ... More
Type III Solar Radio Burst Source Region Splitting Due to a Quasi-Separatrix LayerNov 14 2017We present low-frequency (80-240 MHz) radio imaging of type III solar radio bursts observed by the Murchison Widefield Array (MWA) on 2015/09/21. The source region for each burst splits from one dominant component at higher frequencies into two increasingly-separated ... More
A Rule of Thumb for the Detectability of Gravitational-Wave BurstsMar 31 2013We derive a simple relationship between the energy emitted in gravitational waves for a narrowband source and the distance to which that emission can be detected by a single detector. We consider linearly polarized, elliptically polarized, and unpolarized ... More
L^p regularity of homogeneous elliptic differential operators with constant coefficients on R^NJul 06 2015Jun 23 2016Let $A$ be a homogeneous elliptic differential operator of order $m$ on $% \Bbb{R}^{N}$ with constant complex coefficients. A partial version of the main result is as follows: Suppose that $u\in L_{loc}^{1}$ and that $Au\in L^{p}$ for some $1<p<\infty ... More
Evolution of the X-ray Properties of Clusters of GalaxiesJul 06 2002The amount and nature of the evolution of the X-ray properties of clusters of galaxies provides information on the formation of structure in the universe and on the properties of the universe itself. The cluster luminosity - temperature relation does ... More
X-ray Temperatures for the EMSS High Redshift Cluster Sample: Constraints on Cosmology and the Dark Energy Equation of StateApr 06 2004We measure the X-ray temperature (and luminosity) with ASCA of all but one cluster in the Einstein Extended Medium Sensitivity Survey (EMSS) high redshift (z > 0.3) sample. We compare these data to a complete sample of low redshift clusters that also ... More
Null models for network dataJan 27 2012The analysis of datasets taking the form of simple, undirected graphs continues to gain in importance across a variety of disciplines. Two choices of null model, the logistic-linear model and the implicit log-linear model, have come into common use for ... More
Minimax rank estimation for subspace trackingJun 17 2009Jan 21 2010Rank estimation is a classical model order selection problem that arises in a variety of important statistical signal and array processing systems, yet is addressed relatively infrequently in the extant literature. Here we present sample covariance asymptotics ... More
$L^{p}$ measure of growth and higher order Hardy-Sobolev-Morrey inequalitiesJun 20 2016Nov 27 2016When the growth at infinity of a function $u$ on $\Bbb{R}^{N}$ is compared with the growth of $|x|^{s}$ for some $s\in \Bbb{R},$ this comparison is invariably made pointwise. This paper argues that the comparison can also be made in a suitably defined ... More
Cluster X-ray Luminosity EvolutionAug 08 2001Whether the X-ray luminosities of clusters of galaxies evolve has been a contentious issue for over ten years. However, the data available to address this issue have improved dramatically as cluster surveys from the ROSAT archive near completion. There ... More
Unification of different views of decoherence and discordOct 07 2011Mar 23 2012Macroscopic behavior such as the lack of interference patterns has been attributed to "decoherence", a word with several possible definitions such as (1) the loss of off-diagonal density matrix elements, (2) the flow of information to the environment, ... More
Companions to Young StarsAug 03 2002Brown dwarfs occupy the important region in the mass range between stars and planets. Their existence, ambigious until only recently, and their properties give insight into stellar and planetary formation. We present statistical results of an infrared, ... More
Collapse of the quantum correlation hierarchy links entropic uncertainty to entanglement creationMar 14 2012Nov 10 2012Quantum correlations have fundamental and technological interest, and hence many measures have been introduced to quantify them. Some hierarchical orderings of these measures have been established, e.g., discord is bigger than entanglement, and we present ... More
$L^{p}$ measure of growth and higher order Hardy-Sobolev-Morrey inequalitiesJun 20 2016When the growth at infinity of a function $u$ on $\Bbb{R}^{N}$ is compared with the growth of $|x|^{s}$ for some $s\in \Bbb{R},$ this comparison is invariably made pointwise. This paper argues that the comparison can also be made in a suitably defined ... More
Point process modeling for directed interaction networksNov 08 2010Nov 20 2012Network data often take the form of repeated interactions between senders and receivers tabulated over time. A primary question to ask of such data is which traits and behaviors are predictive of interaction. To answer this question, a model is introduced ... More
Wigner's theorem for an infinite setApr 24 2016It is well known that the closed subspaces of a Hilbert space form an orthomodular lattice. Elements of this orthomodular lattice are the propositions of a quantum mechanical system represented by the Hilbert space, and by Gleason's theorem atoms of this ... More
Weakly Warped Extra Dimensions and SN1987ADec 14 2000Feb 15 2001The neutrino pulse from SN1987A provides one of the most rigourous constraints on models of extra dimensions. Previously, calculations have been done to bound the size of these extra dimensions in the case when the metric was factorizable. Here we consider ... More
Role of complementarity in superdense codingAug 07 2013Nov 26 2013The complementarity of two observables is often captured in uncertainty relations, which quantify an inevitable tradeoff in knowledge. Here we study complementarity in the context of an information processing task: we link the complementarity of two observables ... More
Baire category and the exterior of convex setsJun 09 2012Jul 22 2012The main result can be given a short and elementary proof which has been incorporated into Lemma 3.2 of arXiv:1206.5775
Entropic framework for wave-particle duality in multipath interferometersDec 30 2015Jun 09 2016An interferometer - no matter how clever the design - cannot reveal both the wave and particle behavior of a quantum system. This fundamental idea has been captured by inequalities, so-called wave-particle duality relations (WPDRs), that upper bound the ... More
Measuring Cosmological Parameters from the Evolution of Cluster X-ray TemperaturesFeb 18 2000We have determined the cluster X-ray temperature function from two flux- and redshift-limited samples of clusters. The first sample is comprised of 25 clusters with average redshift 0.05. The local temperature function derived from it supercedes the one ... More
X-ray Properties of High Redshift ClustersSep 27 2001We describe the ensemble X-ray properties of high redshift clusters with emphasis on changes with respect to the local population. Cluster X-ray luminosity evolution is detected in five nearly independent surveys. The relevant issue now is characterizing ... More
Non-negative discord strengthens the subadditivity of quantum entropy functionsJan 10 2011The definition of quantum discord is generalized to allow for any concave entropy function, and its non-negativity strengthens the subadditivity condition for that entropy function. In a sense, this condition is intermediate in strength between subadditivity ... More
Helicity asymmetry of optically-pumped NMR spectra in GaAsJan 21 2008May 09 2008The origin of helicity asymmetries in the optically-pumped NMR signal and hyperfine shift in GaAs is derived analytically and tested experimentally. The ratio of the optically-pumped to the equilibrium electron polarizations is a key parameter in determining ... More
Special embeddings of weighted Sobolev spaces with nontrivial power weightsSep 07 2011Sep 09 2011In prior work, the author has characterized the real numbers $a,b,c$ and $1\leq p,q,r<\infty $ such that the weighted Sobolev space $W_{\{a,b\}}^{(q,p)}(R^{N}\backslash \{0}):=\{u\in L_{loc}^{1}(R^{N}\backslash \{0}):|x|^{\frac{a}{q}}u\in L^{q}(R^{N}),|x|^{\frac{b}{p}}\nabla ... More
Embeddings of weighted Sobolev spaces and generalized Caffarelli-Kohn-Nirenberg inequalitiesJun 24 2011Aug 23 2011We characterize all the real numbers a,b,c and 1<= p,q,r<infty such that the weighted Sobolev space W_{a,b}^(q,p)(R^N\{0}) with power weights |x|^a and |x|^b is continuously embedded into L^{r}(R^N;|x|^cdx). Furthermore, we show that this embedding is ... More
Integral inequalities for infimal convolution and Hamilton-Jacobi equationsJan 19 2015Let $f,g:\Bbb{R}^{N}\rightarrow (-\infty ,\infty ]$ be Borel measurable, bounded below and such that $\inf f+\inf g\geq 0.$ We prove that with $ m_{f,g}:=(\inf f-\inf g)/2,$ the inequality $||(f-m_{f,g})^{-1}||_{\phi }+||(g+m_{f,g})^{-1}||_{\phi }\leq ... More
Continuum and spectral line observations of the OH Megamaser galaxy Arp 220Feb 20 2003We present MERLIN observations of the continuum (both 1.6 and 5 GHz) and OH maser emission towards Arp220. the correct spatial configuration of the various componnents of the galaxy is revealed. In the eastern component the masers are shown to be generally ... More
Searching for diffuse light in the M96 GroupJun 26 2014Jun 29 2016We present deep, wide-field imaging of the M96 galaxy group (also known as the Leo I Group). Down to surface brightness limits of $\mu_{B}=30.1$ and $\mu_{V}=29.5$, we find no diffuse, large-scale optical counterpart to the "Leo Ring", an extended HI ... More
A Star in the M31 Giant Stream: the Highest Negative Stellar Velocity KnownNov 16 2009We report on a single star, B030D, observed as part of a large survey of objects in M31, which has the unusual radial velocity of -780 km/s. Based on details of its spectrum, we find that the star is an F supergiant, with a circumstellar shell. The evolutionary ... More
Deep CCD Surface Photometry of Galaxy Clusters II: Searching for Intracluster Starlight in non-cD clustersMar 17 2004We report the search for intracluster light in four Abell Type II/III (non-cD) galaxy clusters: Abell 801, 1234, 1553, & 1914. We find on average that these clusters contain $\sim$ 10% of their detected stellar luminosity in a diffuse component. We show ... More
Using Intracluster Light to Study Cluster EvolutionMar 14 2003We present some early results from our deep imaging survey of galaxy clusters intended to detect and study intracluster light (ICL). From our observations to date, we find that ICL is common in galaxy clusters, and that substructure in the ICL also appears ... More
The Connection Between Diffuse Light and Intracluster Planetary Nebulae in the Virgo ClusterJun 25 2009We compare the distribution of diffuse intracluster light detected in the Virgo Cluster via broadband imaging with that inferred from searches for intracluster planetary nebulae (IPNe). We find a rough correspondence on large scales (~ 100 kpc) between ... More
Results from a diffuse intracluster light surveyOct 20 2003We give an update of our ongoing survey for intracluster light (ICL), in a sample of distant Abell clusters. We find that the amount of intracluster starlight is comparable to that seen in nearby clusters, and that tidal debris appears to be common.
Diffuse Tidal Structures in the Halos of Virgo EllipticalsApr 09 2010May 06 2010We use deep V-band surface photometry of five of the brightest elliptical galaxies in the Virgo cluster to search for diffuse tidal streams, shells, and plumes in their outer halos (r > 50 kpc). We fit and subtract elliptical isophotal models from the ... More
Optical Colors of Intracluster Light in the Virgo Cluster CoreMar 10 2010Mar 07 2011We continue our deep optical imaging survey of the Virgo cluster using the CWRU Burrell Schmidt telescope by presenting B-band surface photometry of the core of the Virgo cluster in order to study the cluster's intracluster light (ICL). We find ICL features ... More
Implementation of a goodness-of-fit test for finding optimal concurrent radio and γ-ray pulsar light curvesNov 03 2016Since the launch of the Fermi Large Area Telescope in 2008 the number of known {\gamma}-ray pulsars has increased immensely to over 200, many of which are also visible in the radio and X-ray bands. Seyffert et al. (2011) demonstrated how constraints on ... More
Dynamical ultrafast all-optical switching of planar GaAs/AlAs photonic microcavitiesJun 15 2007Sep 11 2007The authors study the ultrafast switching-on and -off of planar GaAs/AlAs microcavities. Up to 0.8% refractive index changes are achieved by optically exciting free carriers at 1720 nm and a pulse energy of 1.8 micro Joules. The cavity resonance is dynamically ... More
Modelling the $γ$-ray and radio light curves of the double pulsar systemNov 04 2014Guillemot et al. recently reported the discovery of $\gamma$-ray pulsations from the 22.7ms pulsar (pulsar A) in the famous double pulsar system J0737-3039A/B. The $\gamma$-ray light curve (LC) of pulsar A has two peaks separated by approximately half ... More
Implementation of a goodness-of-fit test for finding optimal concurrent radio and γ-ray pulsar light curvesNov 03 2016Nov 04 2016Since the launch of the Fermi Large Area Telescope in 2008 the number of known ${\gamma}$-ray pulsars has increased immensely to over 200, many of which are also visible in the radio and X-ray bands. Seyffert et al. (2011) demonstrated how constraints ... More
Energetic Particles of Cosmic Accelerators II: Active Galactic Nuclei and Gamma-ray BurstsMar 11 2019The high-energy universe has revealed that energetic particles are ubiquitous in the cosmos and play a vital role in the cultivation of cosmic environments on all scales. Though they play a key role in cultivating the cosmological environment and/or enabling ... More
Structure of Magnetic Lanthanide Clusters from Far-IR Spectroscopy: Tb (n = 5-9)Nov 27 2012Small lanthanide clusters have interesting magnetic properties, but their structures are unknown. We have identified the structures of small terbium cluster cations Tb (n = 5-9) in the gas phase, by analysis of their vibrational spectra. The spectra have ... More
The anatomy of $γ$-ray pulsar light curvesJan 27 2015We previously obtained constraints on the viewing geometries of 6 Fermi LAT pulsars using a multiwavelength approach (Seyffert et al., 2011). To obtain these constraints we compared the observed radio and $\gamma$-ray light curves (LCs) for those 6 pulsars ... More
Constraining viewing geometries of pulsars with single-peaked gamma-ray profiles using a multiwavelength approachJan 20 2012Jan 23 2012Since the launch of the Large Area Telescope (LAT) on board the Fermi spacecraft in June 2008, the number of observed gamma-ray pulsars has increased dramatically. A large number of these are also observed at radio frequencies. Constraints on the viewing ... More
Very Fine Time-Resolved Spectral Studies of the Vela PulsarDec 18 2009The Vela pulsar is one of the most exciting gamma-ray sources and has been at the forefront of high-energy pulsar science since the detection of gamma-ray pulsations at the radio period by SAS-2 in 1975. With the unprecedented angular resolution, effective ... More
Nanophotonic hybridization of narrow atomic cesium resonances and photonic stop gaps of opaline nanostructuresSep 11 2014We study a hybrid system consisting of a narrowband atomic optical resonance and the long-range periodic order of an opaline photonic nanostructure. To this end, we have infiltrated atomic cesium vapor in a thin silica opal photonic crystal. With increasing ... More
Kerr and free-carrier ultrafast all-optical switching of GaAs/AlAs nanostructures near the three-photon edge of GaAsJun 19 2008We performed non-degenerate pump-probe experiments on a GaAs/AlAs photonic structure. We switched the photonic properties using the optical Kerr effect and free carriers excited by three photon absorption. From these measurements we extracted the non-degenerate ... More
ESCAPE - Echo SCraper and ClAssifier of PErsons: A novel tool to facilitate using voice-controlled devices for researchJun 16 2017Smart devices have become common place in many homes, and these devices can be utilized to provide support for people with mental or physical deficits. Voice-controlled assistants are a class of smart device that collect a large amount of data in the ... More
High pressure electron spin resonance of the endohedral fullerene $^{15}\mathrm{N@C}_{60}$Dec 16 2017We measure the electron spin resonance spectrum of the endohedral fullerene molecule $^{15}\mathrm{N@C}_{60}$ at pressures ranging from atmospheric pressure to 0.25 GPa, and find that the hyperfine coupling increases linearly with pressure. We present ... More
Estimating principal components of covariance matrices using the Nyström methodNov 29 2011Nov 30 2011Covariance matrix estimates are an essential part of many signal processing algorithms, and are often used to determine a low-dimensional principal subspace via their spectral decomposition. However, exact eigenanalysis is computationally intractable ... More
Improved entropic uncertainty relations and information exclusion relationsJul 16 2013Feb 18 2014The uncertainty principle can be expressed in entropic terms, also taking into account the role of entanglement in reducing uncertainty. The information exclusion principle bounds instead the correlations that can exist between the outcomes of incompatible ... More
Effective temperatures in a simple model of non-equilibrium, non-Markovian dynamicsJan 26 2006The concept of effective temperatures in nonequilibrium systems is studied within an exactly solvable model of non-Markovian diffusion. The system is coupled to two heat baths which are kept at different temperatures: one ('fast') bath associated with ... More
Skellam shrinkage: Wavelet-based intensity estimation for inhomogeneous Poisson dataMay 20 2009May 29 2009The ubiquity of integrating detectors in imaging and other applications implies that a variety of real-world data are well modeled as Poisson random variables whose means are in turn proportional to an underlying vector-valued signal of interest. In this ... More
Co-clustering separately exchangeable network dataDec 17 2012Jan 16 2014This article establishes the performance of stochastic blockmodels in addressing the co-clustering problem of partitioning a binary array into subsets, assuming only that the data are generated by a nonparametric process satisfying the condition of separate ... More
Next-to-Leading Order Predictions for Dark Matter Production at Hadron CollidersNov 27 2012We provide Next-to-Leading Order (NLO) predictions for Dark Matter (DM) production in association with either a jet or a photon at hadron colliders. In particular we study the production of a pair of fermionic DM particles through a mediator which couples ... More
Wave Function of the Radion in the dS and AdS Brane WorldsFeb 05 2001Jul 30 2001We study the linearized metric perturbation corresponding to the radion for the generalization of the five dimensional two brane setup of Randall and Sundrum to the case when the curvature of each brane is locally constant but non-zero. We find the wave ... More
Hermite and Laguerre $β$-ensembles: asymptotic corrections to the eigenvalue densitySep 12 2005Jun 28 2006We consider Hermite and Laguerre $\beta$-ensembles of large $N\times N$ random matrices. For all $\beta$ even, corrections to the limiting global density are obtained, and the limiting density at the soft edge is evaluated. We use the saddle point method ... More
The zero locus of an admissible normal functionApr 15 2006We prove that the zero locus of an admissible normal function over an algebraic parameter space S is algebraic in the case where S is a curve.
Network modularity in the presence of covariatesMar 03 2016We characterize the large-sample properties of network modularity in the presence of covariates, under a natural and flexible nonparametric null model. This provides for the first time an objective measure of whether or not a particular value of modularity ... More
On Sunspot and Starspot LifetimesSep 15 2014We consider the lifetimes of spots on the Sun and other stars from the standpoint of magnetic diffusion. While normal magnetic diffusivity predicts lifetimes of sunspots that are too large by at least two orders of magnitude, turbulent magnetic diffusivity ... More
Saxion Emission from SN1987AJul 07 2002Feb 22 2003We study the possibility of emission of the saxion, a superpartner of the axion, from SN1987A. The fact that the observed neutrino pulse from SN1987A is in excellent agreement with the current theory of supernovae places a strong bound on the energy loss ... More
A T-duality interpretation of the relationship between massive and massless magnonic TBA systemsSep 29 2006Jan 09 2007We propose an alternative understanding of the relationship between massive and massless magnonic TBA systems, using the T-duality symmetries of the Homogeneous sine-Gordon models. This is shown to be in agreement with a previous treatment by Dorey, Dunning ... More
Resonant Dark MatterSep 16 2009Nov 11 2009It is usually assumed that dark matter direct detection is sensitive to a large fraction of the dark matter (DM) velocity distribution. We propose an alternative form of dark matter-nucleus scattering which only probes a narrow range of DM velocities ... More
Mass scales and crossover phenomena in the Homogeneous Sine-Gordon ModelsMay 29 2004The finite-size behaviours of the homogeneous sine-Gordon models are analysed in detail, using the thermodynamic Bethe ansatz. Crossovers are observed which allow scales associated with both stable and unstable quantum particles to be picked up. By introducing ... More
Comparison between continuous wave and pulsed laser EQKD systemsSep 04 2008Advances in quantum physics and computational complexity threaten the security of present day cryptographic systems and have driven the development of quantum key distribution (QKD). Entangled quantum key distribution (EQKD) is a secure protocol that ... More
Exit Time Moments and Eigenvalue EstimatesAug 31 2016We study estimates involving the principal Dirichlet eigenvalue associated to a smoothly bounded domain in a complete Riemannian manifold and L1-norms of exit time moments of Brownian motion. Our results generalize a classical inequality of Polya.
An optimal extension theorem for 1-forms and the Lipman-Zariski conjectureJan 30 2013Jul 22 2014Let $X$ be a normal variety. Assume that for some reduced divisor $D \subset X$, logarithmic 1-forms defined on the snc locus of $(X, D)$ extend to a log resolution $\tilde X \to X$ as logarithmic differential forms. We prove that then the Lipman-Zariski ... More
Multiple Shooting Shadowing for Sensitivity Analysis of Chaotic Dynamical SystemsApr 06 2017Sensitivity analysis methods are important tools for research and design with simulations. Many important simulations exhibit chaotic dynamics, including scale-resolving turbulent fluid flow simulations. Unfortunately, conventional sensitivity analysis ... More