Results for "George T. Hall"

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On the Impact of the Cutoff Time on the Performance of Algorithm ConfiguratorsApr 12 2019May 21 2019Algorithm configurators are automated methods to optimise the parameters of an algorithm for a class of problems. We evaluate the performance of a simple random local search configurator (ParamRLS) for tuning the neighbourhood size $k$ of the RLS$_k$ ... More
On the Impact of the Cutoff Time on the Performance of Algorithm ConfiguratorsApr 12 2019Algorithm configurators are automated methods to optimise the parameters of an algorithm for a class of problems. We evaluate the performance of a simple random local search configurator (ParamRLS) for tuning the neighbourhood size $k$ of the RLS$_k$ ... More
Predictions From A U(2) Flavour Symmetry In Supersymmetric TheoriesDec 21 1995In a generic supersymmetric extension of the Standard Model, whether unified or not, a simple and well motivated U(2) symmetry, acting on the lightest two generations, completely solves the flavour changing problem and necessarily leads to a predictive ... More
Very High Energy Observations of PSR B1823-13May 29 2003To date three plerionic systems have been detected as emitters of very energetic photons. As part of an ongoing study of pulsar systems at the Whipple observatory, observations of the plerion PSR B1823-13 are being conducted. Observations were made with ... More
Optical study of hybridization and hidden order in URu$_2$Si$_2$Apr 28 2014We summarize existing optical data of URu$_2$Si$_2$ to clarify the nature of the hidden order transition in this heavy fermion metal. Hybridization develops between 50 K and 17.5 K, and a coherent Drude peak emerges which mirrors the changes in the dc ... More
Canonical correlation analysis between time series and static outcomes, with application to the spectral analysis of heart rate variabilityOct 01 2012May 24 2013Although many studies collect biomedical time series signals from multiple subjects, there is a dearth of models and methods for assessing the association between frequency domain properties of time series and other study outcomes. This article introduces ... More
The UV Properties of SDSS Selected QuasarsNov 17 2006We present an analysis of the broadband UV/optical properties of z<3.4 quasars matched in the Galaxy Evolution Explorer (GALEX) General Data Release 1 (GR1) and the Sloan Digital Sky Survey Data Release 3 (SDSS DR3). Of the 6371 DR3 quasars covered by ... More
Complex Molecule Formation in Grain MantlesMar 31 2010Context: Complex molecules such as ethanol and dimethyl ether have been observed in a number of hot molecular cores and hot corinos. Attempts to model the molecular formation process using gas phase only models have so far been unsuccessful. Aims : To ... More
Prediction in functional linear regressionFeb 22 2007There has been substantial recent work on methods for estimating the slope function in linear regression for functional data analysis. However, as in the case of more conventional finite-dimensional regression, much of the practical interest in the slope ... More
Time to Extinction in Subcritical Two-Sex Branching ProcessesNov 04 2013Lower and upper bounds for the cumulative distribution function (cdf) of the time to extinction in a subcritical two-sex branching process are derived. A recursive procedure for approximating this cdf is also utilized. The results are illustrated with ... More
Thermodynamics of free domain wall and overlap fermionsNov 16 2000Studies of non-interacting lattice fermions give an estimate of the size of discretization errors and finite size effects for more interesting problems like finite temperature QCD. We present a calculation of the thermodynamic equation of state for free ... More
Dynamical lattice QCD thermodynamics with domain wall fermionsOct 22 1999We present results from simulations of two flavor QCD thermodynamics at N_t=4 with domain wall fermions. In contrast to other lattice fermion formulations, domain wall fermions preserve the full chiral symmetry of the continuum at finite lattice spacing ... More
Lattice supersymmetry with domain wall fermionsNov 16 2000Supersymmetry, like Poincare symmetry, is softly broken at finite lattice spacing provided the gaugino mass term is strongly suppressed. Domain wall fermions provide the mechanism for suppressing this term by approximately imposing chiral symmetry on ... More
Looking for pentaquarks in Lattice QCDJan 14 2005Pentaquark states in lattice QCD probably lie close in energy to two particle scattering states. Correctly identifying the resonant state is a challenging, yet tractable, problem given the terascale computing facilities available today. We summarize the ... More
What can Lattice QCD theorists learn from NMR spectroscopists?Mar 22 2004Jan 14 2005Euclidean-time hadron correlation functions computed in Lattice QCD (LQCD) are modeled by a sum of decaying exponentials, reminiscent of the exponentially damped sinusoid models of free induction decay (FID) in Nuclear Magnetic Resonance (NMR) spectroscopy. ... More
A Weyl Creation Algebra Approach to the Riemann HypothesisJan 07 2013Feb 25 2013We sketch a Weyl creation operator approach to the Riemann Hypothesis; i.e.,arithmetic on the Weyl algebras with ergodic theory to transport operators. We prove that finite Hasse-Dirichlet alternating zeta functions or eta functions can be induced from ... More
Lattice supersymmetry with domain wall fermionsDec 13 2000Supersymmetry, like Poincare symmetry, is softly broken at finite lattice spacing provided the gaugino mass term is strongly suppressed. Domain wall fermions provide the mechanism for suppressing this term by approximately imposing chiral symmetry. We ... More
Strong Interactions for the LHCDec 10 2008Dynamical electroweak symmetry breaking (DEWSB) has been a viable option for the completion of the standard model for over thirty years. Precision electroweak studies indicate that the new strong interactions that break EW symmetry cannot be a scaled-up ... More
A 233 km Circumference Tunnel for $e^+$$e^-$, $p$$\bar {p}$, and $μ^{+} μ^{-}$ CollidersDec 05 2011Feb 29 2012In 2001 a cost analysis survey was conducted to build a 233km circumference tunnel in northern Illinois in which to build a Very Large Hadron Collider. Ten years later I have reexamined the proposal, taking into consideration the technological advancements ... More
The Independent Chip Model and Risk AversionNov 16 2009We consider the Independent Chip Model (ICM) for expected value in poker tournaments. Our first result is that participating in a fair bet with one other player will always lower one's expected value under this model. Our second result is that the expected ... More
Conference Summary: AGN Physics with the Sloan Digital Sky SurveyMay 20 2004May 27 2004The ``AGN Physics with the Sloan Digital Sky Survey'' conference was held at Princeton University in July 2003 to bring together groups working inside and outside of the SDSS collaboration at radio through X-ray wavelengths to discuss the common goal ... More
Counting Descent Pairs with Prescribed Tops and BottomsOct 20 2006Given sets X and Y of positive integers and a permutation sigma = sigma_1, sigma_2, ..., sigma_n in S_n, an X,Y-descent of sigma is a descent pair sigma_i > sigma_{i+1} whose "top" sigma_i is in X and whose "bottom" sigma_{i+1} is in Y. We give two formulas ... More
Comment on "Quantum phase for an arbitrary system with finite-dimensional Hilbert space"Jun 20 2012Nov 14 2012A construction of covariant quantum phase observables, for Hamiltonians with a finite number of energy eigenvalues, has been recently given by D. Arsenovic et al. [Phys. Rev. A 85, 044103 (2012)]. For Hamiltonians generating periodic evolution, we show ... More
Topological geon black holes in Einstein-Yang-Mills theoryJan 23 2010Mar 15 2011We construct topological geon quotients of two families of Einstein-Yang-Mills black holes. For Kuenzle's static, spherically symmetric SU(n) black holes with n>2, a geon quotient exists but generically requires promoting charge conjugation into a gauge ... More
Jamming in Fixed-Rate Wireless Systems with Power Constraints - Part I: Fast Fading ChannelsAug 26 2008This is the first part of a two-part paper that studies the problem of jamming in a fixed-rate transmission system with fading. Both transmitter and jammer are subject to power constraints which can be enforced over each codeword short-term / peak) or ... More
Momentum of electromagnetic fields, speed of light in moving media, and the photon massMay 21 2010In both the equations for matter and light wave propagation, the momentum of the electromagnetic fields Pe reflects the relevant em interaction. As a review of some applications of wave propagation properties, an optical experiment which tests the speed ... More
Half-Duplex Active Eavesdropping in Fast Fading Channels: A Block-Markov Wyner Secrecy Encoding SchemeFeb 05 2010In this paper we study the problem of half-duplex active eavesdropping in fast fading channels. The active eavesdropper is a more powerful adversary than the classical eavesdropper. It can choose between two functional modes: eavesdropping the transmission ... More
$B_7$, $B_8$ and chiral Ward identitiesSep 30 2005We present recent progress in understanding weak matrix elements on the lattice. We use HYP staggered fermions in quenched QCD to study numerically various properties of the $K^+\to\pi^+$ amplitudes of the electroweak penguin operators $Q_7$ and $Q_8$. ... More
Distinguished minimal toplogical lassosAug 12 2013A classical result in distance based tree-reconstruction characterizes when for a distance $D$ on some finite set $X$ there exist a uniquely determined dendrogram on $X$ (essentially a rooted tree $T=(V,E)$ with leaf set $X$ and no degree two vertices ... More
Detection of Node Clones in Wireless Sensor Network Using Detection ProtocolsMar 11 2014Wireless sensor networks consist of hundreds to thousands of sensor nodes and are widely used in civilian and security applications. One of the serious physical attacks faced by the wireless sensor network is node clone attack. Thus two node clone detection ... More
Taming the Runaway Problem of Inflationary LandscapesJan 05 2006Mar 15 2006A wide variety of vacua, and their cosmological realization, may provide an explanation for the apparently anthropic choices of some parameters of particle physics and cosmology. If the probability on various parameters is weighted by volume, a flat potential ... More
Gravitino or Axino Dark Matter with Reheat Temperature as high as $10^{16}$ GeVNov 15 2016A new scheme for LSP dark matter is introduced and studied in theories of TeV supersymmetry with a QCD axion, $a$, and a high reheat temperature after inflation, $T_R$. A large overproduction of axinos ($\tilde{a}$) and gravitinos ($\tilde{G}$) from scattering ... More
Large non-Gaussianity from two-component hybrid inflationDec 04 2008Feb 12 2009We study the generation of non-Gaussianity in models of hybrid inflation with two inflaton fields, (2-brid inflation). We analyse the region in the parameter and the initial condition space where a large non-Gaussianity may be generated during slow-roll ... More
Conditions for large non-Gaussianity in two-field slow-roll inflationJul 07 2008Oct 06 2008We study the level of primordial non-Gaussianity in slow-roll two-field inflation. Using an analytic formula for the nonlinear parameter f_nl in the case of a sum or product separable potential, we find that it is possible to generate significant non-Gaussianity ... More
Gravitino or Axino Dark Matter with Reheat Temperature as high as $10^{16}$ GeVNov 15 2016Nov 29 2016A new scheme for lightest supersymmetric particle (LSP) dark matter is introduced and studied in theories of TeV supersymmetry with a QCD axion, $a$, and a high reheat temperature after inflation, $T_R$. A large overproduction of axinos ($\tilde{a}$) ... More
SaxiGUTs and their PredictionsMar 14 2016Oct 11 2016We introduce a class of unified supersymmetric axion theories with unified and PQ symmetries broken by the same set of fields at a scale $\sim 2\times 10^{16}$ GeV. A typical domain wall number of order 30 leads to an axion decay constant $f_a$ of order ... More
The Weak Scale from BBNSep 01 2014The measured values of the weak scale, $v$, and the first generation masses, $m_{u,d,e}$, are simultaneously explained in the multiverse, with all these parameters scanning independently. At the same time, several remarkable coincidences are understood. ... More
Effect of magnetic field on the phase transition in a dusty plasmaSep 12 2017The formation of self-consistent crystalline structure is a well-known phenomenon in complex plasmas. In most experiments the pressure and rf power are the main controlling parameters in determining the phase of the system. We have studied the effect ... More
Cost-effective aperture arrays for SKA Phase 1: single or dual-band?Mar 02 2012An important design decision for the first phase of the Square Kilometre Array is whether the low frequency component (SKA1-low) should be implemented as a single or dual-band aperture array; that is, using one or two antenna element designs to observe ... More
A Cosmological Upper Bound on Superpartner MassesFeb 11 2013If some superpartners were in thermal equilibrium in the early universe, and if the lightest superpartner is a cosmologically stable gravitino, then there is a powerful upper bound on the scale of the superpartner masses. Typically the bound is below ... More
A Natural SUSY Higgs Near 125 GeVDec 12 2011Feb 14 2012The naturalness of a Higgs boson with a mass near 125 GeV is explored in a variety of weak-scale supersymmetric models. A Higgs mass of this size strongly points towards a non-minimal implementation of supersymmetry. The Minimal Supersymmetric Standard ... More
The near-infrared spectrum of ethynyl radicalAug 08 2016Transient diode laser absorption spectroscopy has been used to measure three strong vibronic bands in the near infrared spectrum of the C$_2$H, ethynyl, radical not previously observed in the gas phase. The radical was produced by ultraviolet excimer ... More
Analytic solutions to the central spin problem for Nitrogen Vacancy centres in diamondSep 19 2013Due to interest in both solid state based quantum computing architectures and the application of quantum mechanical systems to nanomagnetometry, there has been considerable recent attention focused on understanding the microscopic dynamics of solid state ... More
Yukawa Unification and the Superpartner Mass ScaleJun 22 2012Naturalness in supersymmetry (SUSY) is under siege by increasingly stringent LHC constraints, but natural electroweak symmetry breaking still remains the most powerful motivation for superpartner masses within experimental reach. If naturalness is the ... More
Prospects and Blind Spots for Neutralino Dark MatterNov 20 2012Using a simplified model framework, we assess observational limits and discovery prospects for neutralino dark matter, taken here to be a general admixture of bino, wino, and Higgsino. Experimental constraints can be weakened or even nullified in regions ... More
Quantum Gravito-Optics: A Light Route from Semiclassical Gravity to Quantum GravityAug 03 2015Quantum gravity remains an elusive theory, in spite of our thorough understanding of the quantum theory and the general theory of relativity separately, presumably due to the lack of any observational clues. We argue that the theory of quantum gravity ... More
The Pion Form Factor at Large Momentum TransferOct 24 2007We present our calculations of the electromagnetic form factor of pions. We explore the properties of pion form factor at momentum transfer larger than previous studies by including more combinations of source and sink momenta and using more configurations.We ... More
Precise Gravitational Tests via the SEE Mission: A Proposal for Space-Based MeasurementsMay 20 2010The objective of a SEE mission is to support development of unification theory by carrying out sensitive gravitational tests capable of determining whether various alternative theories are compatible with nature. Gravitation is a key "missing link" in ... More
The Effect of Reduced Spatial Symmetries on Lattice States: Results for Non-zero Linear MomentumJul 05 2006Jul 18 2006The irreducible representations of the cubic space group are described and used to determine the mapping of continuum states to lattice states with non-zero linear momentum. The Clebsch-Gordan decomposition is calculated from the character table for the ... More
Hall effect and inter-chain magneto-optical properties of coupled Luttinger liquidsAug 03 2000We consider the Hall effect in a system of weakly coupled Luttinger chains. We obtain the full conductivity tensor in the absence of dissipation along the chains. We show that while the dependence of the Hall and transverse conductivities on temperature ... More
Optimal Strategies for Gaussian Jamming in Block-Fading Channels under Delay and Power ConstraintsJul 03 2007Sep 28 2009Without assuming any knowledge on source's codebook and its output signals, we formulate a Gaussian jamming problem in block fading channels as a two-player zero sum game. The outage probability is adopted as an objective function, over which transmitter ... More
Spectral Energy Distributions and Multiwavelength Selection of Type 1 QuasarsJan 24 2006Jun 26 2006We present an analysis of the mid-infrared (MIR) and optical properties of type 1 (broad-line) quasars detected by the Spitzer Space Telescope. The MIR color-redshift relation is characterized to z=3, with predictions to z=7. We demonstrate how combining ... More
Rigorous Comparison of Gravimetry Employing Atom Interferometers and the Measurement of Gravitational Time DilationJun 30 2011We present a gravitationally rigorous and clear answer, in the negative, to the question whether gravimetry with atom interferometers is equivalent to the the measurement of the relative gravitational time dilation of two clocks separated in space. Though ... More
Interacting staggered domain wall fermionsAug 22 2002The behavior of staggered domain wall fermions in the presence of gauge fields is presented. In particular, their response to gauge fields with nontrivial topology is discussed.
Prony methods for extracting excited statesFeb 27 2019We propose an algebraic method for extracting excited states from lattice gauge theory correlation functions. Instead of fitting to a sum of decaying exponentials, we adopt a variant of Prony's method to obtain $M$ energies (exponential decay rates) by ... More
Fringe field simulations of a non-scaling FFAG acceleratorFeb 03 2012Fixed-field Alternating Gradient (FFAG) accelerators offer the potential of high-quality, moderate energy ion beams at low cost. Modeling of these structures is challenging with conventional beam tracking codes because of the large radial excursions of ... More
Some remarks on an old problem of radiation and gravityAug 03 2015The assumed universality of the equivalence principle suggests that a particle in a gravitational field has identical physics to one in an accelerated frame. Yet, energy considerations prohibit radiation from a static particle in a gravitational field ... More
Shrinkage Confidence ProceduresMar 22 2012The possibility of improving on the usual multivariate normal confidence was first discussed in Stein (1962). Using the ideas of shrinkage, through Bayesian and empirical Bayesian arguments, domination results, both analytic and numerical, have been obtained. ... More
Jamming in Fixed-Rate Wireless Systems with Power Constraints - Part II: Parallel Slow Fading ChannelsAug 26 2008This is the second part of a two-part paper that studies the problem of jamming in a fixed-rate transmission system with fading. In the first part, we studied the scenario with a fast fading channel, and found Nash equilibria of mixed strategies for short ... More
Prony methods for extracting excited statesFeb 27 2019Mar 05 2019We propose an algebraic method for extracting excited states from lattice gauge theory correlation functions. Instead of fitting to a sum of decaying exponentials, we adopt a variant of Prony's method to obtain $M$ energies (exponential decay rates) by ... More
Universality in the Gravitational Stretching of Clocks, Waves and Quantum StatesJun 21 2011There are discernible and fundamental differences between clocks, waves and physical states in classical physics. These fundamental concepts find a common expression in the context of quantum physics in gravitational fields; matter and light waves, quantum ... More
Neutrino-Accelerated Hot Hydrogen BurningJun 23 2006Jun 25 2006We examine the effects of significant electron anti-neutrino fluxes on hydrogen burning. Specifically, we find that the bottleneck weak nuclear reactions in the traditional pp-chain and the hot CNO cycle can be accelerated by anti-neutrino capture, increasing ... More
Lepton Number-Driven Sterile Neutrino Production in the Early UniverseFeb 22 2008Jul 18 2008We examine medium-enhanced, neutrino scattering-induced decoherent production of dark matter candidate sterile neutrinos in the early universe. In cases with a significant net lepton number we find two resonances, where the effective in-medium mixing ... More
Particle creation from the quantum stress tensorMar 17 2015Among the different methods to derive particle creation, finding the quantum stress tensor expectation value gives a covariant quantity which can be used for examining the back-reaction issue. However this tensor also includes vacuum polarization in a ... More
Strong Morita equivalence of operator spacesMar 31 2016Sep 24 2016We introduce and examine the notions of strong $\Delta$-equivalence and strong TRO equivalence for operator spaces. We show that they behave in an analogous way to how strong Morita equivalence does for the category of C*-algebras. In particular, we prove ... More
Mixing patterns and individual differences in networksOct 02 2018Apr 17 2019We study mixing patterns in networks, meaning the propensity for nodes of different kinds to connect to one another. The phenomenon of assortative mixing, whereby nodes prefer to connect to others that are similar to themselves, has been widely studied, ... More
Gravitational waves at their own gravitational speedNov 12 2018Gravitational waves propagate at the speed of light in general relativity, because of its special relativistic basis. However, light propagation is linked to the electromagnetic phenomena, with the permittivity and permeability constants as the determining ... More
The staggered domain wall fermion methodJul 16 2002Oct 04 2002A different lattice fermion method is introduced. Staggered domain wall fermions are defined in 2n+1 dimensions and describe 2^n flavors of light lattice fermions with exact U(1) x U(1) chiral symmetry in 2n dimensions. As the size of the extra dimension ... More
Quantum Coherence of Relic NeutrinosNov 26 2008Jun 01 2009We argue that in at least a portion of the history of the universe the relic background neutrinos are spatially-extended, coherent superpositions of mass states. We show that an appropriate quantum mechanical treatment affects the neutrino mass values ... More
Particle creation rate for dynamical black holesNov 13 2015Oct 02 2016We present the particle creation probability rate around a general black hole as an outcome of quantum fluctuations. Using the uncertainty principle for these fluctuation, we derive a new ultraviolet frequency cutoff for the radiation spectrum of a dynamical ... More
Cosmic Matter Flux May Turn Hawking Radiation OffAug 04 2014Dec 06 2014An astrophysical (cosmological) black hole forming in a cosmological context will be subject to a flux of infalling matter and radiation, which will cause the outer apparent horizon (a marginal trapping surface) to be spacelike \cite{ellisetal14}. As ... More
Deriving Potential Coronal Magnetic Fields from Vector MagnetogramsMar 30 2015Jun 16 2016The minimum-energy configuration for the magnetic field above the solar photosphere is curl-free (hence, by Ampere's law, also current-free), so can be represented as the gradient of a scalar potential. Since magnetic fields are divergence free, this ... More
Energy-efficient Traffic Bypassing in LTE HetNets with Mobile RelaysJul 15 2015One of the core technologies being standardized by 3GPP for LTE-A is the introduction of Relay Nodes (RNs). RNs are intended for ensuring coverage at cell edges as well as for the provision of enhanced capacity at hot spot areas. An extension to this ... More
A brief review of recent advances on the Mott transition: unconventional transport, spectral weight transfers, and critical behaviourNov 23 2003May 19 2004Strongly correlated metals close to the Mott transition display unusual transport regimes, together with large spectral weight transfers in optics and photoemission. We briefly review the theoretical understanding of these effects, based on the dynamical ... More
Angular Momentum on the Lattice: The Case of Non-Zero Linear MomentumJul 14 2005Jul 18 2006The irreducible representations (IRs) of the double cover of the Euclidean group with parity in three dimensions are subduced to the corresponding cubic space group. The reduction of these representations gives the mapping of continuum angular momentum ... More
Multiparticle States and the Hadron Spectrum on the LatticeJul 05 2006Jul 18 2006The Clebsch-Gordan decomposition is calculated for direct products of the irreducible representations of the cubic space group. These results are used to identify multiparticle states which appear in the hadron spectrum on the lattice. Consideration of ... More
Significance of bar quenching in the global quenching of star formationJul 16 2019The suppression of star formation in the inner kiloparsec regions of barred disk galaxies due to the action of bars is known as bar quenching. We investigate here the significance of bar quenching in the global quenching of star formation in the barred ... More
Efficient Implementation of Elastohydrodynamics via Integral OperatorsMar 08 2019The dynamics of geometrically non-linear flexible filaments play an important role in a host of biological processes, from flagella-driven cell transport to the polymeric structure of complex fluids. Such problems have historically been computationally ... More
Efficient Implementation of Elastohydrodynamics via Integral OperatorsMar 08 2019Mar 27 2019The dynamics of geometrically non-linear flexible filaments play an important role in a host of biological processes, from flagella-driven cell transport to the polymeric structure of complex fluids. Such problems have historically been computationally ... More
From Lattice Strong Dynamics to PhenomenologyDec 18 2013We present updated results on the chiral properties of SU(3) gauge theories with 2 and 6 massless Dirac fermions in the fundamental representation. Our focus is on the ratio $\langle \bar{\psi} \psi \rangle / F^3$, where $\langle \bar{\psi} \psi \rangle$ ... More
Lattice Study of Conformal Behavior in SU(3) Yang-Mills TheoriesJan 23 2009May 15 2009Using lattice simulations, we study the extent of the conformal window for an SU(3) gauge theory with N_f Dirac fermions in the fundamental representation. We extend our recently reported work, describing the general framework and the lattice simulations ... More
Lattice Study of the Conformal Window in QCD-like TheoriesDec 04 2007May 05 2008Using lattice simulations, we study the extent of the conformal window for an $\text{SU}(3)$ gauge theory with $N_f$ Dirac fermions in the fundamental representation. We present evidence that the infrared behavior is conformal for $12 \leq N_f \leq 16$, ... More
The Kinematics and Physical Conditions of the Ionized Gas in NGC 4593 from Chandra High-Energy Grating SpectroscopyApr 22 2003Apr 24 2003We observed the Seyfert 1 galaxy NGC 4593 with the Chandra high energy transmission gratings and present a detailed analysis of the soft X-ray spectrum. We measure strong absorption lines from He-like O, Ne, Mg, Si, H-like N, O, Ne, Mg, Si and highly ... More
Chandra Grating Observations of Seyfert 1 GalaxiesNov 21 2001We present new results from a Chandra HETG observation of NGC 5548 and give a comparison of absorption and emission features found in other Seyfert 1 galaxies using Chandra grating observations. Deep soft X-ray edges are seen in Mkn 509 and NGC 3783, ... More
The uTPC Method: Improving the Position Resolution of Neutron Detectors Based on MPGDsJan 20 2015Due to the Helium-3 crisis, alternatives to the standard neutron detection techniques are becoming urgent. In addition, the instruments of the European Spallation Source (ESS) require advances in the state of the art of neutron detection. The instruments ... More
Freeze-In Dark Matter with Displaced Signatures at CollidersJun 24 2015Dec 17 2015Dark matter, $X$, may be generated by new physics at the TeV scale during an early matter-dominated (MD) era that ends at temperature $T_R \ll {\rm TeV}$. Compared to the conventional radiation-dominated (RD) results, yields from both Freeze-Out and Freeze-In ... More
Magnetic Properties of a Two-Dimensional Mixed-Spin SystemJun 17 2002Using a Langmuir-Blodgett (LB) synthesis method, novel two-dimensional (2D) mixed-spin magnetic systems, in which each magnetic layer is both structurally and magnetically isolated, have been generated. Specifically, a 2D Fe-Ni cyanide-bridged network ... More
Effects of Interstitial Oxygen and Carbon on Niobium Superconducting CavitiesDec 25 2016Jan 31 2017We present results on the effects of interstitial oxygen and carbon on a bulk-niobium superconducting radio-frequency cavity. Previous experiments have shown that high-temperature (~800 $^\circ\text{C}$) nitrogen-doping plays the dominant role in the ... More
Two-state Bogoliubov theory of a molecular Bose gasSep 30 2015We present an analytic Bogoliubov description of a BEC of polar molecules trapped in a quasi-2D geometry and interacting via internal state-dependent dipole-dipole interactions. We derive the mean-field ground-state energy functional, and we derive analytic ... More
Ultra-sensitive Diamond Magnetometry Using Optimal Dynamic DecouplingMar 19 2010New magnetometry techniques based on Nitrogen Vacancy (NV) defects in diamond have received much attention of late as a means to probe nanoscale magnetic environments. The sensitivity of a single NV magnetometer is primarily determined by the transverse ... More
Effect of Magnetization Inhomogeneity on Magnetic Microtraps for AtomsMay 03 2006Nov 24 2006We report on the origin of fragmentation of ultracold atoms observed on a permanent magnetic film atom chip. A novel technique is used to characterize small spatial variations of the magnetic field near the film surface using radio frequency spectroscopy ... More
Detection of krypton in xenon for dark matter applicationsMar 14 2011Dec 03 2011We extend our technique for observing very small concentrations of impurities in xenon gas to the problem of krypton detection. We use a conventional mass spectrometer to identify the krypton content of the xenon, but we improve the sensitivity of the ... More
A simple high-sensitivity technique for purity analysis of xenon gasFeb 14 2010Mar 16 2010We report on the development and performance of a high-sensitivity purity-analysis technique for gaseous xenon. The gas is sampled at macroscopic pressure from the system of interest using a UHV leak valve. The xenon present in the sample is removed with ... More
Single molecule NMR detection and spectroscopy using single spins in diamondJul 31 2013Nanomagnetometry using the nitrogen-vacancy (NV) centre in diamond has attracted a great deal of interest because of the combined features of room temperature operation, nanoscale resolution and high sensitivity. One of the important goals for nano-magnetometry ... More
Suppression of intrinsic neutron background in the Multi-Grid detectorOct 19 2018Dec 02 2018One of the key requirements for neutron scattering instruments is the Signal-to-Background ratio (SBR). This is as well a design driving requirement for many instruments at the European Spallation Source (ESS), which aspires to be the brightest neutron ... More
Fast and Accurate Binary Response Mixed Model Analysis via Expectation PropagationMay 22 2018Expectation propagation is a general prescription for approximation of integrals in statistical inference problems. Its literature is mainly concerned with Bayesian inference scenarios. However, expectation propagation can also be used to approximate ... More
Adaptive Bayesian Spectral Analysis of Nonstationary Biomedical Time SeriesSep 02 2016Oct 04 2016Many studies of biomedical time series signals aim to measure the association between frequency-domain properties of time series and clinical and behavioral covariates. However, the time-varying dynamics of these associations are largely ignored due to ... More
Analysis of the $\tilde{A}-\tilde{X}$ bands of the Ethynyl Radical near 1.48$μ$m and Re-evaluation of $\tilde{X}$ State EnergiesMar 15 2018We report the observation and analysis of spectra in part of the near-infrared spectrum of C$_2$H, originating in rotational levels in the ground and lowest two excited bending vibrational levels of the ground $\tilde{X}\,^2\Sigma^+$ state. In the analysis, ... More
Characterization of Potential U.S. Sites for the Cherenkov Telescope ArrayJul 17 2013The Cherenkov Telescope Array (CTA) is a major ground-based observatory proposed for gamma-ray astronomy. CTA is envisioned to consist of two large arrays of atmospheric Cherenkov telescopes for the study of sources of high-energy gamma rays in the energy ... More
English Conversational Telephone Speech Recognition by Humans and MachinesMar 06 2017One of the most difficult speech recognition tasks is accurate recognition of human to human communication. Advances in deep learning over the last few years have produced major speech recognition improvements on the representative Switchboard conversational ... More