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Results for "C. Olkin"

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Evidence for longitudinal variability of ethane ice on the surface of PlutoJun 06 2014Aug 08 2014We present the results of an investigation using near-infrared spectra of Pluto taken on 72 separate nights using SpeX/IRTF. These data were obtained between 2001 and 2013 at various sub-observer longitudes. The aim of this work was to confirm the presence ... More
Near-Infrared Spectral Monitoring of Pluto's Ices II: Recent Decline of CO and N$_2$ Ice AbsorptionsFeb 19 2014IRTF/SpeX observations of Pluto's near-infrared reflectance spectrum during 2013 show vibrational absorption features of CO and N$_2$ ices at 1.58 and 2.15 {\mu}m, respectively, that are weaker than had been observed during the preceding decade. To reconcile ... More
Near-Infrared Spectral Monitoring of Pluto's Ices: Spatial Distribution and Secular EvolutionJan 26 2013We report results from monitoring Pluto's 0.8 to 2.4 {\mu}m reflectance spectrum with IRTF/SpeX on 65 nights over the dozen years from 2001 to 2012. The spectra show vibrational absorption features of simple molecules CH4, CO, and N2 condensed as ices ... More
On the surface composition of Triton's southern latitudesAug 24 2015Nov 20 2015We present the results of an investigation to determine the longitudinal (zonal) distributions and temporal evolution of ices on the surface of Triton. Between 2002 and 2014, we obtained 63 nights of near-infrared (0.67-2.55 $\mu$m) spectra using the ... More
The CH4 cycles on Pluto over seasonal and astronomical timescalesMar 05 2019New Horizons observations suggest that CH4 on Pluto has a complex history, involving reservoirs of different composition, thickness and stability controlled by volatile processes occurring on different timescales. In order to interpret these observations, ... More
Impact Craters on Pluto and Charon Indicate a Deficit of Small Kuiper Belt ObjectsFeb 27 2019The flyby of Pluto and Charon by the New Horizons spacecraft provided high-resolution images of cratered surfaces embedded in the Kuiper belt, an extensive region of bodies orbiting beyond Neptune. Impact craters on Pluto and Charon were formed by collisions ... More
Ice Mineralogy Across and Into the Surfaces of Pluto, Triton, and ErisMar 30 2012We present three near-infrared spectra of Pluto taken with the IRTF and SpeX, an optical spectrum of Triton taken with the MMT and the Red Channel Spectrograph, and previously published spectra of Pluto, Triton, and Eris. We combine these observations ... More
Near-Infrared Spectral Monitoring of Triton with IRTF/SpeX II: Spatial Distribution and Evolution of IcesAug 18 2009Aug 18 2009This report arises from an ongoing program to monitor Neptune's largest moon Triton spectroscopically in the 0.8 to 2.4 micron range using IRTF/SpeX. Our objective is to search for changes on Triton's surface as witnessed by changes in the infrared absorption ... More
Pao-Lu Hsu (Xu, Bao-lu): The Grandparent of Probability and Statistics in ChinaOct 03 2012The years 1910-1911 are auspicious years in Chinese mathematics with the births of Pao-Lu Hsu, Luo-Keng Hua and Shiing-Shen Chern. These three began the development of modern mathematics in China: Hsu in probability and statistics, Hua in number theory, ... More
Development and Performance of the PHOT (Portable High-Speed Occultation Telescope) SystemsFeb 14 2011The PHOT (Portable High-Speed Occultation Telescope) systems were developed for the specific purpose of observing stellar occultations by solar system objects. Stellar occultations have unique observing constraints: they may only be observable from certain ... More
In Situ Observations of Preferential Pickup Ion Heating at an Interplanetary ShockJul 13 2018Non-thermal pickup ions (PUIs) are created in the solar wind (SW) by charge-exchange between SW ions (SWIs) and slow interstellar neutral atoms. It has long been theorized, but not directly observed, that PUIs should be preferentially heated at quasi-perpendicular ... More
Reorientation of Sputnik Planitia implies a Subsurface Ocean on PlutoMar 13 2019The deep nitrogen-covered Sputnik Planitia (SP; informal name) basin on Pluto is located very close to the longitude of Pluto's tidal axis[1] and may be an impact feature [2], by analogy with other large basins in the solar system[3,4]. Reorientation[5-7] ... More
Convection in a volatile nitrogen-ice-rich layer drives Pluto's geological vigorMar 13 2019The vast, deep, volatile-ice-filled basin informally named Sputnik Planum is central to Pluto's geological activity[1,2]. Composed of molecular nitrogen, methane, and carbon monoxide ices[3], but dominated by N2-ice, this ice layer is organized into cells ... More
Formation of Charon's Red Poles From Seasonally Cold-Trapped VolatilesMar 09 2019A unique feature of Pluto's large satellite Charon is its dark red northern polar cap. Similar colours on Pluto's surface have been attributed to organic macromolecules produced by energetic radiation processing of hydrocarbons. The polar location of ... More
Pluto's Haze as a Surface MaterialMar 09 2019Pluto's atmospheric haze settles out rapidly compared with geological timescales. It needs to be accounted for as a surface material, distinct from Pluto's icy bedrock and from the volatile ices that migrate via sublimation and condensation on seasonal ... More
Moments of minors of Wishart matricesApr 22 2006Nov 05 2008For a random matrix following a Wishart distribution, we derive formulas for the expectation and the covariance matrix of compound matrices. The compound matrix of order $m$ is populated by all $m\times m$-minors of the Wishart matrix. Our results yield ... More
Interstellar Pickup Ion Observations to 38 AUOct 14 2017We provide the first direct observations of interstellar H+ and He+ pickup ions in the solar wind from 22 AU to 38 AU. We use the Vasyliunas and Siscoe model functional form to quantify the pickup ion distributions, and while the fit parameters generally ... More
Global Albedos of Pluto and Charon from LORRI New Horizons ObservationsApr 20 2016The exploration of the Pluto-Charon system by the New Horizons spacecraft represent the first opportunity to understand the distribution of albedo and other photometric properties of the surfaces of objects in the Solar System's "Third Zone" within the ... More
Pluto's global surface composition through pixel-by-pixel Hapke modeling of New Horizons Ralph/LEISA dataApr 28 2016On July 14th 2015, NASA's New Horizons mission gave us a first view of the Pluto system. The complex compositional diversity of Pluto's encounter hemisphere was revealed by the Ralph/LEISA infrared spectrometer on board of New Horizons. We present compositional ... More
The Puzzling Detection of X-rays From Pluto by ChandraOct 25 2016Using Chandra ACIS-S, we have obtained imaging Xray spectrophotometry of the Pluto system in support of the New Horizons flyby on 14 July 2015. 174 ksec of observations were obtained on 4 visits in Feb 2014 to Aug 2015. We measured a net signal of 6.8 ... More
Pluto's Atmosphere Does Not CollapseSep 03 2013Combining stellar occultation observations probing Pluto's atmosphere from 1988 to 2013 and models of energy balance between Pluto's surface and atmosphere, we conclude that Pluto's atmosphere does not collapse at any point in its 248-year orbit. The ... More
Global Albedos of Pluto and Charon from LORRI New Horizons ObservationsApr 20 2016Jan 09 2017The exploration of the Pluto-Charon system by the New Horizons spacecraft represents the first opportunity to understand the distribution of albedo and other photometric properties of the surfaces of objects in the Solar System's "Third Zone" of distant ... More
Modeling glacial flow on and onto Pluto's Sputnik PlanumJun 18 2016Observations of Pluto's surface made by the New Horizons spacecraft indicates present-day nitrogen ice glaciation in and around the basin known as Sputnik Planum. Motivated by these observations, we have developed an evolutionary glacial flow model of ... More
A Search for Temporal Changes on Pluto and CharonNov 07 2017A search for temporal changes on Pluto and Charon was motivated by (1) the discovery of young surfaces in the Pluto system that imply ongoing or recent geologic activity, (2) the detection of active plumes on Triton during the Voyager 2 flyby, and (3) ... More
New Horizons Constraints on Charon's Present Day AtmosphereAug 24 2016We report on a variety of standard techniques used by New Horizons including a solar ultraviolet occultation, ultraviolet airglow observations, and high-phase look-back particulate search imaging to search for an atmosphere around Pluto's large moon Charon ... More
Overview of initial results from the reconnaissance flyby of a Kuiper Belt planetesimal: 2014 MU69Jan 09 2019Jan 24 2019The centerpiece objective of the NASA New Horizons first Kuiper Extended Mission (KEM-1) was the close flyby of the Kuiper Belt Object KBO) 2014 MU69, nicknamed Ultima Thule. On 1 Jan 2019 this flyby culminated, making the first close observations of ... More
Pluto's global surface composition through pixel-by-pixel Hapke modeling of New Horizons Ralph/LEISA dataApr 28 2016Nov 30 2016On July 14th 2015, NASA's New Horizons mission gave us an unprecedented detailed view of the Pluto system. The complex compositional diversity of Pluto's encounter hemisphere was revealed by the Ralph/LEISA infrared spectrometer on board of New Horizons. ... More
Ralph: A Visible/Infrared Imager for the New Horizons Pluto/Kuiper Belt MissionSep 26 2007The New Horizons instrument named Ralph is a visible/near infrared multi-spectral imager and a short wavelength infrared spectral imager. It is one of the core instruments on New Horizons, NASA's first mission to the Pluto/Charon system and the Kuiper ... More
Modeling glacial flow on and onto Pluto's Sputnik PlanitiaJun 18 2016Jul 26 2018Observations of Pluto's surface made by the New Horizons spacecraft indicates present-day nitrogen ice glaciation in and around the basin known as Sputnik Planum. Motivated by these observations, we have developed an evolutionary glacial flow model of ... More
The nitrogen cycles on Pluto over seasonal and astronomical timescalesApr 06 2018Pluto's landscape is shaped by the cycles of the volatile ices covering its surface. In particular, the Sputnik Planitia (SP) ice sheet displays a large diversity of terrains, with bright and dark plains, pits, topographic depressions and evidences of ... More
Plutos interaction with its space environment: Solar Wind, Energetic Particles & DustMay 03 2016The New Horizons spacecraft carried three instruments that measured the space environment near Pluto as it flew by on 14 July 2015. The Solar Wind Around Pluto instrument revealed an interaction region confined sunward of Pluto to within about 6 Pluto ... More
Inflight Radiometric Calibration of New Horizons' Multispectral Visible Imaging Camera (MVIC)Mar 29 2016We discuss two semi-independent calibration techniques used to determine the in-flight radiometric calibration for the New Horizons' Multi-spectral Visible Imaging Camera (MVIC). The first calibration technique compares the observed stellar flux to modeled ... More
Surface Compositions Across Pluto and CharonApr 18 2016The New Horizons spacecraft mapped colors and infrared spectra across the encounter hemispheres of Pluto and Charon. The volatile ices CH$_4$, CO, and N$_2$, that dominate Pluto's surface, have complicated spatial distributions resulting from sublimation, ... More
Pluto's lower atmosphere and pressure evolution from ground-based stellar occultations, 1988-2016Mar 06 2019Context. Pluto's tenuous nitrogen (N2) atmosphere undergoes strong seasonal effects due to high obliquity and orbital eccentricity, and has been recently (July 2015) observed by the New Horizons spacecraft. Goals are (i) construct a well calibrated record ... More
The Atmosphere of Pluto as Observed by New HorizonsApr 18 2016Observations made during the New Horizons flyby provide a detailed snapshot of the current state of Pluto's atmosphere. While the lower atmosphere (at altitudes <200 km) is consistent with ground-based stellar occultations, the upper atmosphere is much ... More
The Small Satellites of Pluto as Observed by New HorizonsApr 18 2016The New Horizons mission has provided resolved measurements of Pluto's moons Styx, Nix, Kerberos, and Hydra. All four are small, with equivalent spherical diameters of $\approx$40 km for Nix and Hydra and ~10 km for Styx and Kerberos. They are also highly ... More
Great Expectations: Plans and Predictions for New Horizons Encounter with Kuiper Belt Object 2014 MU69 ('Ultima Thule')Aug 06 2018The New Horizons encounter with the cold classical Kuiper Belt object (KBO) 2014 MU69 (informally named 'Ultima Thule,' hereafter Ultima) on 1 January 2019 will be the first time a spacecraft has ever closely observed one of the free-orbiting small denizens ... More
The Geology of Pluto and Charon Through the Eyes of New HorizonsApr 19 2016NASA's New Horizons spacecraft has revealed the complex geology of Pluto and Charon. Pluto's encounter hemisphere shows ongoing surface geological activity centered on a vast basin containing a thick layer of volatile ices that appears to be involved ... More
Training of Instrumentalists and Development of New Technologies on SOFIAMar 25 2009This white paper is submitted to the Astronomy and Astrophysics 2010 Decadal Survey (Astro2010)1 Committee on the State of the Profession to emphasize the potential of the Stratospheric Observatory for Infrared Astronomy (SOFIA) to contribute to the training ... More
Physical Characterization of TNOs with JWSTNov 03 2015Studies of the physical properties of Trans-Neptunian Objects (TNOs) are a powerful probe into the processes of planetesimal formation and solar system evolution. JWST will provide unique new capabilities for such studies. Here we outline where the capabilities ... More
Haze in Pluto's AtmosphereFeb 24 2017Feb 28 2017Haze in Pluto's atmosphere was detected in images by both the Long Range Reconnaissance Imager (LORRI) and the Multispectral Visible Imaging Camera (MVIC) on New Horizons. LORRI observed haze up to altitudes of at least 200 km above Pluto's surface at ... More
High-Precision Orbit Fitting and Uncertainty Analysis of (486958) 2014 MU69May 06 2018NASA's New Horizons spacecraft will conduct a close flyby of the cold classical Kuiper Belt Object (KBO) designated (486958) 2014 MU69 on January 1, 2019. At a heliocentric distance of 44 AU, "MU69" will be the most distant object ever visited by a spacecraft. ... More
Decay width of light quark hybrid meson from the latticeMar 06 2006Apr 13 2006Lattice QCD with $N_f=2$ flavours of sea quark is used to explore the spectrum and decay of a $J^{PC}=1^{-+}$ spin-exotic hybrid meson. We test lattice determination of S-wave decay amplitudes at threshold using $b_1 \to \pi \omega$ where agreement with ... More
Staggered Chiral Perturbation Theory with Heavy-Light MesonsSep 08 2004We merge heavy quark effective theory with staggered chiral perturbation theory to calculate heavy-light (B, D) meson quantities. We present results at NLO for the $B(D)$ meson decay constant in the partially quenched and full QCD cases, and discuss the ... More
Transverse stability of periodic traveling waves in Kadomtsev-Petviashvili equations: A numerical studyAug 16 2011We numerically investigate transverse stability and instability of so-called cnoidal waves, i.e., periodic traveling wave solutions of the Korteweg-de Vries equation, under the time-evolution of the Kadomtsev-Petviashvili equation. In particular, we find ... More
Azimuthal decorrelation of Mueller-Navelet jets at the Tevatron and the LHCApr 25 2007Nov 05 2008We study the production of Mueller-Navelet jets at hadron colliders in the Balitsky-Fadin-Kuraev-Lipatov (BFKL) framework. We show that a measurement of the relative azimuthal angle \Delta\Phi between the jets can provide a good testing ground for corrections ... More
High-dielectric constant and wide band gap inverse silver oxide phases of the ordered ternary alloys of SiO$_{2}$, GeO$_{2}$ and SnO$_{2}$Jul 14 2006Dec 01 2006High-dielectric constant and wide band gap oxides have important technological applications. The crystalline oxide polymorphs having lattice constant compatibility to silicon are particularly desirable. One recently reported candidate is the inverse silver ... More
Single crystal growth and anisotropy of CeRuPOSep 26 2007Dec 05 2007We report on the single crystal growth of the ferromagnetic Kondo lattice system CeRuPO using a Sn flux method. Magnetic susceptibility and electrical resistivity measurements indicate strong anisotropy of this structurally layered compound. They evidence ... More
8--13 micron spectroscopy of luminous and ultraluminous infrared galaxiesMar 17 1999New moderate-resolution mid-infrared spectroscopy at 10 micron of 27 infrared galaxies is presented. The galaxies have been chosen from three 60 micron selected and one 12 micron selected complete flux-limited catalogs of galaxies; 17 of these sources ... More
Solving the mystery of IapetusApr 29 2005Jul 19 2007For a much better-founded theory, check Wing Ip, GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L16203, doi:10.1029/2005GL025386, 2006 (see also
Compton X-ray and Gamma-ray Emission from Extended Radio GalaxiesApr 06 2007The extended lobes of radio galaxies are examined as sources of X-ray and gamma-ray emission via inverse Compton scattering of 3K background photons. The Compton spectra of two exemplary examples, Fornax A and Centaurus A, are estimated using available ... More
Panchromatic Views of Large-scale Extragalactic JetsDec 14 2006Highlights of recent observations of extended jets in AGN are presented. Specifically, we discuss new spectral constraints enabled by Spitzer, studies of the highest-redshift (z~4) radio/X-ray quasar jets, and a new VLBA detection of superluminal motion ... More
FIRST `Winged' and `X'-shaped Radio Source CandidatesJan 10 2007Mar 16 2008A small number of double-lobed radio galaxies (17 from our own census of the literature) show an additional pair of low surface brightness `wings', thus forming an overall `X'-shaped appearance. The origin of the wings in these radio sources is unclear. ... More
Transverse charge and magnetization densities in the nucleon's chiral peripheryOct 02 2013In the light-front description of nucleon structure the electromagnetic form factors are expressed in terms of frame-independent transverse densities of charge and magnetization. Recent work has studied the transverse densities at peripheral distances ... More
Chiral dynamics and peripheral transverse densitiesAug 07 2013In the partonic (or light-front) description of relativistic systems the electromagnetic form factors are expressed in terms of frame-independent charge and magnetization densities in transverse space. This formulation allows one to identify the chiral ... More
Torsion cohomology classes and algebraic cycles on complex projective manifoldsMar 16 2004Jan 15 2005Atiyah and Hirzebruch gave examples ofeven degree torsion classes in the singularcohomology of a smooth complex projective manifold, which arenot Poincar\'{e} dual to an algebraiccycle. We notice that the order ofthese classes are small comparedto the ... More
Series of convex functions: subdifferential, conjugate and applications to entropy minimizationJun 03 2015A formula for the sub\-differential of the sum of a series of convex functions defined on a Banach space was provided by X. Y. Zheng in 1998. In this paper, besides a slight extension to locally convex spaces of Zheng's results, we provide a formula for ... More
Small-x QCD effects in forward-jet and Mueller-Navelet jet productionOct 20 2005Mar 07 2006We investigate small-x QCD effects in forward-jet production in deep inelastic scattering in the kinematic regime where the virtuality of the photon and the transverse momentum of the jet are two hard scales of about the same magnitude. We show that the ... More
The Gravitational Radiaton degrees of freedom in Hyperbolic Systems for Numerical RelativityAug 06 2002The gravitational radiation degrees of freedom of freedom are described in the framework of the 3+1 decomposition of spacetime. The relationship with eigenfields of the Kidder-Scheel-Teukolsky (KST) equations is established. This relationship is used ... More
Bound-free $\mathbf{e}^+ \mathbf{e}^-$ pair creation with a linearly polarized laser field and a nuclear fieldJul 28 2008The process of bound-free pair production of electrons and positrons in combined laser and Coulomb fields is investigated. It is assumed that an ion collides at relativistic speed with an intense x-ray laser beam of linear polarization. The process proceeds ... More
Towards Automated Verification of Web ServicesNov 11 2011This paper proposes the use of model-checking software technology for the verification of workflows and business processes behaviour based on web services, namely the use of the SPIN model checker. Since the specification of a business process behaviour ... More
Approximate solutions for N-body Hamiltonians with identical particles in D dimensionsJul 19 2013Nov 13 2013A method based on the envelope theory is presented to compute approximate solutions for $N$-body Hamiltonians with identical particles in $D$ dimensions ($D\ge 2$). In some favorable cases, the approximate eigenvalues can be analytically determined and ... More
Schur-finiteness in $λ$-ringsNov 05 2010Nov 17 2011We introduce the notion of a Schur-finite element in a $\lambda$-ring.
Pion and Kaon masses in Staggered Chiral Perturbation TheoryApr 21 2003Jul 07 2003We show how to compute chiral logarithms that take into account both the $\cO(a^2)$ taste-symmetry breaking of staggered fermions and the fourth-root trick that produces one taste per flavor. The calculation starts from the Lee-Sharpe Lagrangian generalized ... More
Heavy-Light Semileptonic Decays in Staggered Chiral Perturbation TheoryApr 05 2007Jun 26 2007We calculate the form factors for the semileptonic decays of heavy-light pseudoscalar mesons in partially quenched staggered chiral perturbation theory (\schpt), working to leading order in $1/m_Q$, where $m_Q$ is the heavy quark mass. We take the light ... More
Pseudoscalar Decay Constants in Staggered Chiral Perturbation TheoryJun 20 2003Sep 29 2003In a continuation of an ongoing program, we use staggered chiral perturbation theory to calculate the one-loop chiral logarithms and analytic terms in the pseudoscalar meson leptonic decay constants, $f_{\pi^+_5}$ and $f_{K^+_5}$. We consider the partially ... More
New construction of algebro-geometric solutions to the Camassa-Holm equation and their numerical evaluationSep 24 2011Dec 06 2011An independent derivation of solutions to the Camassa-Holm equation in terms of multi-dimensional theta functions is presented using an approach based on Fay's identities. Reality and smoothness conditions are studied for these solutions from the point ... More
Super-Massive Neutron StarsNov 30 2007We present here the results of Arecibo timing of PSR B1516+02B, a 7.95-ms pulsar in a binary system with a ~0.17 solar mass companion and an orbital period of 6.85 days located in the globular cluster M5. The eccentricity of the orbit (e = 0.14) has allowed ... More
Observations of Galaxy Clustering at High RedshiftNov 25 1998This paper reviews the current status of measurements of galaxy clustering at high redshifts (z > 0.3). The focus is on the inherent limitations in the observation and interpretation of the ``evolution of clustering''. It is likely that results from the ... More
Radio-Quiet Quasars in the Direction of the Northern Hubble Deep FieldSep 13 2000We match quasars discovered in a multi-color survey centered on the northern Hubble Deep Field (HDF) with radio sources from an ultra-deep radio survey. Although 3 out of 12 quasars are detected at a level below 0.2 mJy at 1.4 GHz, all of the quasars ... More
Projective invariants of CR-hypersurfacesOct 27 2010We study the equivalence problem under projective transformation for CR-hypersurfaces of complex projective space. A complete set of projective differential invariants for analytic hypersurfaces is given. The self-dual strongly C-linearly convex hypersurfaces ... More
Hadronic matrix elements of neutral-meson mixing through lattice QCDSep 23 2015Neutral-meson mixing is loop suppressed in the Standard Model, leading to the possibility of enhanced sensitivity to new physics. The uncertainty in Standard Model predictions for $B$-meson oscillation frequencies is dominated by theoretical uncertainties ... More
On some results of Cufaro Petroni about Student t-processesMar 21 2008This paper deals with Student t-processes as studied in (Cufaro Petroni N 2007 J. Phys. A, Math. Theor. 40(10), 2227-2250). We prove and extend some conjectures expressed by Cufaro Petroni about the asymptotical behavior of a Student t-process and the ... More
On the cusp form motives in genus 1 and level 1Apr 20 2005Jan 23 2006We prove that the moduli space of stable n-pointed curves of genus one and the projector associated to the alternating representation of the symmetric group on n letters define (for n>1) the Chow motive corresponding to cusp forms of weight n+1 for SL(2,Z). ... More
Understanding Convolutional Neural Networks with A Mathematical ModelSep 14 2016This work attempts to address two fundamental questions about the structure of the convolutional neural networks (CNN): 1) why a non-linear activation function is essential at the filter output of every convolutional layer? 2) what is the advantage of ... More
Threshold effects in open-string theoryMay 05 1996May 14 1996We analyze the one-loop effective gauge-field action in $Z_2$-orbifold compactifications of type-I theory. We show how, for non-abelian group factors, the threshold effects are ultraviolet finite though given entirely by a six-dimensional field theory ... More
Hidden Symmetry of a Fluid Dynamical ModelMay 28 2001A connection between solutions of the relativistic d-brane system in (d+1) dimensions with the solutions of a Galileo invariant fluid in d-dimensions is by now well established. However, the physical nature of the light-cone gauge description of a relativistic ... More
A quantum topological phase transition at the microscopic levelJul 13 2007Mar 01 2008We study a quantum phase transition between a phase which is topologically ordered and one which is not. We focus on a spin model, an extension of the toric code, for which we obtain the exact ground state for all values of the coupling constant that ... More
Explicit Gravitational Radiation in Hyperbolic Systems for Numerical RelativityFeb 14 2002Feb 28 2002A method for studying the causal structure of space-time evolution systems is presented. This method, based on a generalization of the well known Riemann problem, provides intrinsic results which can be interpreted from the geometrical point of view. ... More
Flux Limiter Methods in 3D Numerical RelativityFeb 28 2002New numerical methods have been applied in relativity to obtain a numerical evolution of Einstein equations much more robust and stable. Starting from 3+1 formalism and with the evolution equations written as a FOFCH (first-order flux conservative hyperbolic) ... More
Basic Morita equivalences and a conjecture of Sasaki for cohomology of block algebras of finite groupsJun 14 2015We show, using basic Morita equivalences between block algebras of finite groups, that the Conjecture of H. Sasaki from [9] is true for a new class of blocks called nilpotent covered blocks. When this Conjecture is true we define some transfer maps between ... More
Staggered Chiral Perturbation Theory for Heavy-Light MesonsOct 18 2005Jan 25 2006We incorporate heavy-light mesons into staggered chiral perturbation theory, working to leading order in 1/m_Q, where m_Q is the heavy quark mass. At first non-trivial order in the chiral expansion, staggered taste violations affect the chiral logarithms ... More
Electroweak standard model at finite temperature in presence of a bosonic chemical potentialMar 15 2007Dec 30 2010We study the electroweak standard model at finite temperature in presence of a bosonic chemical potential associated with the conserved electromagnetic current. To preserve the thermodynamic equilibrium of the system, the thermal medium is neutralized ... More
Replica methods for loopy sparse random graphsJan 29 2016I report on the development of a novel statistical mechanical formalism for the analysis of random graphs with many short loops, and processes on such graphs. The graphs are defined via maximum entropy ensembles, in which both the degrees (via hard constraints) ... More
Statistical Mechanics of Recurrent Neural Networks I. StaticsJun 01 2000A lecture notes style review of the equilibrium statistical mechanics of recurrent neural networks with discrete and continuous neurons (e.g. Ising, coupled-oscillators). To be published in the Handbook of Biological Physics (North-Holland). Accompanied ... More
Observational constraints upon quintessence models arising from moduli fieldsApr 14 2000Jun 12 2000We study observational constraints on cosmological models with a quintessence arising from moduli fields. The scalar field potential is given by a double exponential potential V=V_0 exp(-A e^{sqrt{2} kappa phi}). After reviewing the properties of the ... More
Light-front representation of chiral dynamics with Delta isobar and large-N_c relationsMar 29 2016Transverse densities describe the spatial distribution of electromagnetic current in the nucleon at fixed light-front time. At peripheral distances b = O(M_pi^{-1}) the densities are governed by chiral dynamics and can be calculated model-independently ... More
The classical overdetermined Serrin problemNov 29 2017Nov 30 2017In this survey we consider the classical overdetermined problem which was studied by Serrin in 1971. The original proof relies on Alexandrov's moving plane method, maximum principles, and a refinement of Hopf's boundary point Lemma. Since then other approaches ... More
CNN as Guided Multi-layer RECOS TransformJan 30 2017Feb 19 2017There is a resurging interest in developing a neural-network-based solution to the supervised machine learning problem. The convolutional neural network (CNN) will be studied in this note. To begin with, we introduce a RECOS transform as a basic building ... More
Generating functional analysis of Minority Games with real market historiesOct 13 2004It is shown how the generating functional method of De Dominicis can be used to solve the dynamics of the original version of the minority game (MG), in which agents observe real as opposed to fake market histories. Here one again finds exact closed equations ... More
Statistical Mechanics of Recurrent Neural Networks II. DynamicsJun 01 2000A lecture notes style review of the non-equilibrium statistical mechanics of recurrent neural networks with discrete and continuous neurons (e.g. Ising, graded-response, coupled-oscillators). To be published in the Handbook of Biological Physics (North-Holland). ... More
Non-equilibrium statistical mechanics of Minority GamesMay 13 2002In this paper I give a brief introduction to a family of simple but non-trivial models designed to increase our understanding of collective processes in markets, the so-called Minority Games, and their non-equilibrium statistical mathematical analysis. ... More
NSV 13983: A New Dwarf Nova in the Period GapJun 17 2008Aims. NSV 13983 is catalogued as a dwarf nova based on a reported outburst from 2005. The system has not yet been studied spectroscopically. We attempt to confirm its nature as a dwarf nova and determine its orbital period. Methods. We derive the orbital ... More
Computation of the topological type of a real Riemann surfaceApr 21 2012We present an algorithm for the computation of the topological type of a real compact Riemann surface associated to an algebraic curve, i.e., its genus and the properties of the set of fixed points of the anti-holomorphic involution $\tau$, namely, the ... More
A new and trivial CP symmetry for extended $A_4$ flavorJan 05 2016May 18 2016The combination of $\nu_\mu$-$\nu_\tau$ exchange together with CP conjugation in the neutrino sector (known as $\mathrm{CP}^{\mu\tau}$ symmetry or $\mu\tau$-reflection) is known to predict the viable pattern: $\theta_{23}=45^\circ$, maximal Dirac CP phase ... More
Symmetric cohomology of groups as a Mackey functorDec 05 2014Symmetric cohomology of groups, defined by M. Staic in [2], is similar to the way one defines the cyclic cohomology for algebras. We show that there is a well-defined restriction, conjugation and transfer map in symmetric cohomology, which form a Mackey ... More
Scaling of the superfluid density in severely underdoped YBa2Cu3O6+yNov 20 2009Recent measurements on extremely-underdoped YBa2Cu3O6+y [Phys. Rev. Lett. 99, 237003 (2007)] have allowed the critical temperature (T_c), superfluid density [rho_0 (T << T_c)] and dc conductivity [sigma_dc (T ~ T_c)] to be determined for a series of electronic ... More
Eclipsing Binary PulsarsApr 05 2004The first eclipsing binary pulsar, PSR B1957+20, was discovered in 1987. Since then, 13 other eclipsing low-mass binary pulsars have been found, 12 of these are in globular clusters. In this paper we list the known eclipsing binary pulsars and their properties, ... More
The Pulsar Population in Globular Clusters and in the GalaxyOct 15 2012Oct 23 2012In this paper, I review some of the basic properties of the pulsar population in globular clusters (GCs) and compare it with the the Galactic disk population. The neutron stars (NSs) in GCs were likely formed - and appear to continue forming - in highly ... More
Quantum-mechanical picture of peripheral chiral dynamicsMar 06 2015The nucleon's peripheral transverse charge and magnetization densities are computed in chiral effective field theory. The densities are represented in first-quantized form, as overlap integrals of chiral light-front wave functions describing the transition ... More