Results for "Ka Wai Ho"

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Dispersion of velocity gradients: Mapping magnetization with the Velocity Gradient TechniqueFeb 08 2018Recent developments of the Velocity Gradient Technique (VGT) show that the velocity provides a robust measure of magnetic field direction. In this paper, we use velocity centroids as the measures of velocity and propose a new way of studying media magnetization. ... More
Bayesian Nonparametric Estimation of a Unimodal Density via two $\mathbf{S}$-pathsSep 02 2006A Bayesian nonparametric method for unimodal densities on the real line is provided by considering a class of species sampling mixture models containing random densities that are unimodal and not necessarily symmetric. This class of densities generalize ... More
Tracing 3D distribution of magnetic fields with gradients of synchrotron polarizationJan 31 2018In this paper, we describe a new technique for probing galactic and extragalactic 2D and 3D distribution of magnetic field using synchrotron polarization. Fluctuations of magnetic field are elongated along the ambient magnetic field directions. As a result, ... More
Pomeranchuk Instability in a non-Fermi Liquid from HolographyMar 14 2012Sep 17 2012The Pomeranchuk instability, in which an isotropic Fermi surface distorts and becomes anisotropic due to strong interactions, is a possible mechanism for the growing number of experimental systems which display transport properties that differ along the ... More
Neutral Order Parameters in Metallic Criticality in d=2+1 from a Hairy Electron StarJun 16 2011We use holography to study the spontaneous condensation of a neutral order parameter in a (2+1)-dimensional field theory at zero-temperature and finite density, dual to the electron star background of Hartnoll and Tavanfar. An appealing feature of this ... More
Non-Fermi Liquid behavior at the Orbital Ordering Quantum Critical Point in the Two-Orbital ModelJul 17 2012Mar 25 2013The critical behavior of a two-orbital model with degenerate $d_{xz}$ and $d_{yz}$ orbitals is investigated by multidimensional bosonization. We find that the corresponding bosonic theory has an overdamped collective mode with dynamical exponent $z=3$, ... More
Diagnostics of turbulence properties through Velocity Gradient Amplitudes: Theory and ObservationsJan 31 2018Based on the properties of magneto-hydrodynamic (MHD) turbulence, the recent development of the Velocity Gradient Technique (VGT) allows observers to trace magnetic field directions using spectroscopic information. In this paper, we explore how the amplitudes ... More
Electron Electric Dipole Moment induced by Octet-Colored ScalarsDec 31 2007An appended sector of two octet-colored scalars, each an electroweak doublet, is an interesting extension of the simple two Higgs doublet model motivated by the minimal flavor violation. Their rich CP violating interaction gives rise to a sizable electron ... More
A proof of the strong twin prime conjectureJun 16 2015Jun 27 2015For integers x and k, let T(x;2k) denote the number of twin prime pairs (p,p+2k) with a distance 2k<=2x**0.5 and p<=x (not p+2k<=x). Let Tg(x;2x**0.5) denote the average of T(x;2k) for all 2k<=2x**0.5. Logically, T(x;2k) should be a function of Tg(x;2x**0.5). ... More
Tilings of the Sphere by Geometrically Congruent Pentagons IOct 08 2013May 08 2014We show that there are no edge-to-edge tilings of the sphere by congruent pentagons beyond the minimal dodecahedron tiling, such that there is a tile with all vertices having degree 3 and the edge length combinations are three of the five possibilities. ... More
Improving Two-Way Selective Decode-and-forward Wireless Relaying with Energy-Efficient One-bit Soft ForwardingJun 20 2012Jan 07 2015Motivated by applications such as battery-operated wireless sensor networks (WSN), we propose an easy-to-implement energy-efficient two-way relaying scheme. In particular, we address the challenge of improving the standard two-way selective decode-and-forward ... More
An Efficient Algorithm for Optimally Solving a Shortest Vector Problem in Compute-and-Forward Protocol DesignOct 16 2014Jun 26 2016We consider the problem of finding the optimal coefficient vector that maximizes the computation rate at a relay in the compute-and-forward scheme. Based on the idea of sphere decoding, we propose a highly efficient algorithm that finds the optimal coefficient ... More
Erratum: "Determining neutron star masses and radii using energy-resolved waveforms of X-ray burst oscillations" (ApJ, 776, 19 [2013])Jan 22 2018This erratum addresses an error in the text of Lo et al. (2013) and more importantly corrects a computational error that was made in all previously published relativistic computations of absolute pulse waveform fluxes produced by hot spots on rotating ... More
Exact Results for the Kepler Problem in General RelativityJul 25 2008Jul 27 2008Exact results are derived, specifically the perihelion shift and the Kepler orbit, for a bound test particle in the Schwarzschild metric with cosmological constant $\Lambda=0$. A series expansion, of $\Delta\phi = 2(2(1-2M/p(3-e))^{-1/2} K((4eM/p)/(1-2M/p(3-e)))-\pi)$, ... More
An Efficient Optimal Algorithm for Integer-Forcing Linear MIMO Receivers DesignOct 20 2016Although multiple-input and multiple-output (MIMO) wireless systems achieve significant data rates (e.g., multiplexing) and reliability (e.g., diversity) and are main enablers for high-rate 5G wireless systems, MIMO receivers require high implementation ... More
Realization of Woodpile Structure Using Optical Interference HolographyJul 15 2006We report the use of a (4+1)-beam optical interference holography technique to fabricate woodpile structures in photo-resists. The configuration consists of 4 linear polarized side beams arranged symmetrically around a circular polarized central beam ... More
On Linear Operator Channels over Finite FieldsFeb 11 2010Apr 14 2010Motivated by linear network coding, communication channels perform linear operation over finite fields, namely linear operator channels (LOCs), are studied in this paper. For such a channel, its output vector is a linear transform of its input vector, ... More
Winning in Sequential Parrondo Games by Players with Short-Term MemoryOct 19 2015Jan 10 2016The original Parrondo game, denoted as AB3, contains two independent games: A and B. The winning or losing of A and B game is defined by the change of one unit of capital. Game A is a losing game if played continuously, with winning probability $p=0.5-\epsilon$, ... More
Data Science at Udemy: Agile Experimentation with AlgorithmsFeb 13 2016In this paper, we describe the data science framework at Udemy, which currently supports the recommender and search system. We explain the motivations behind the framework and review the approach, which allows multiple individual data scientists to all ... More
A Helium nanodrop bouncing off a wallJul 25 2003Aug 10 2003We investigate numerically the quantum collision between a stable Helium nanodrop and an infinitely hard wall in one dimension. The scattering outcome is compared to the same event omitting the quantum pressure. Only the quantum process reflects the effect ... More
The spin parameter of uniformly rotating compact starsNov 16 2010Jan 21 2011We study the dimensionless spin parameter $j (= c J/ (G M^2))$ of uniformly rotating neutron stars and quark stars in general relativity. We show numerically that the maximum value of the spin parameter of a neutron star rotating at the Keplerian frequency ... More
Markov Lemma for Countable AlphabetsJun 02 2010Strong typicality and the Markov lemma have been used in the proofs of several multiterminal source coding theorems. Since these two tools can be applied to finite alphabets only, the results proved by them are subject to the same limitation. Recently, ... More
Dangerous connections: on binding site models of infectious disease dynamicsJan 20 2016Jan 27 2016We formulate models for the spread of infection on networks that are amenable to analysis in the large population limit. We distinguish three different levels: (1) binding sites, (2) individuals, and (3) the population. In the tradition of Physiologically ... More
A Bayes method for a Bathtub Failure Rate via two $\mathbf{S}$-pathsJul 16 2007A class of semi-parametric hazard/failure rates with a bathtub shape is of interest. It does not only provide a great deal of flexibility over existing parametric methods in the modeling aspect but also results in a closed and tractable Bayes estimator ... More
A Bayes method for a monotone hazard rate via S-pathsFeb 21 2005Jul 01 2006A class of random hazard rates, which is defined as a mixture of an indicator kernel convolved with a completely random measure, is of interest. We provide an explicit characterization of the posterior distribution of this mixture hazard rate model via ... More
Voltage-Controlled Berry Phases in Two Coupled Quantum DotsJan 25 2008The voltage-controlled Berry phases in two vertically coupled InGaAs/GaAs quantum dots are investigated theoretically. It is found that Berry phases can be changed dramatically from 0 to 2$\pi$ (or 2$\pi$ to 0) only simply by turning the external voltage. ... More
Applications of Partially Quenched Chiral Perturbation TheoryNov 17 1997Feb 24 1998Partially quenched theories are theories in which the valence- and sea-quark masses are different. In this paper we calculate the nonanalytic one-loop corrections of some physical quantities: the chiral condensate, weak decay constants, Goldstone boson ... More
Chiral perturbation theory for K+ to pi+ pi0 decay in the continuum and on the latticeFeb 14 1997May 16 1997In this paper we use one-loop chiral perturbation theory in order to compare lattice computations of the K+ to pi+ pi0 decay amplitude with the experimental value. This makes it possible to investigate three systematic effects that plague lattice computations: ... More
Signatures of invariant Hermitian forms on irreducible highest weight modulesJan 20 2006Sep 05 2006Perhaps the most important problem in representation theory in the 1970s and early 1980s was the determination of the multiplicity of composition factors in a Verma module. This problem was settled by the proof of the Kazhdan-Lusztig Conjecture which ... More
Global Existence for the Minimal Surface Equation on $\mathbb{R}^{1,1}$Jan 06 2016In a 2004 paper, Lindblad demonstrated that the minimal surface equation on $\mathbb{R}l^{1,1}$ describing graphical time-like minimal surfaces embedded in $\mathbb{R}^{1,2}$ enjoy small data global existence for compactly supported initial data, using ... More
Regular hyperbolicity, dominant energy condition and causality for Lagrangian theory of mapsNov 12 2010May 16 2011The goal of the present paper is three-fold. First is to clarify the connection between the dominant energy condition and hyperbolicity properties of Lagrangian field theories. Second is to provide further analysis on the breakdown of hyperbolicity for ... More
Matter enhanced nu_mu->nu_e signals using various Fermilab main injector beam configurationsJan 10 2001Jan 29 2001We calculate the sensitivity to nu_mu->nu_e appearance oscillations in various Fermilab main injector neutrino beam configurations using simulations of a MINOS-like detector and an OPERA-like detector. We make the assumption of 3 neutrino generations, ... More
Observation of High Energy Quark-Antiquark Elastic Scattering with Mesonic ExchangeMay 21 1993We studied the high energy quark anti-quark elastic scattering with an exchange of a mesonic state in the $t$ channel with $-t/\Lambda_{QCD}^{2} \gg 1$. Two methods are proposed to eliminate the strong background from bare pomeron, reggized gluon and ... More
Tight Algorithms for Vertex Cover with Hard Capacities on Multigraphs and HypergraphsJun 25 2016In this paper we give a f-approximation algorithm for the minimum unweighted Vertex Cover problem with Hard Capacity constraints (VCHC) on f-hypergraphs. This problem generalizes standard vertex cover for which the best known approximation ratio is also ... More
Stability and instability of expanding solutions to the Lorentzian constant-positive-mean-curvature flowApr 01 2014Oct 13 2014We study constant mean curvature Lorentzian hypersurfaces of $\mathbb{R}^{1,d+1}$ from the point of view of its Cauchy problem. We completely classify the spherically symmetric solutions, which include among them a manifold isometric to the de Sitter ... More
A positive mass theorem for two spatial dimensionsFeb 28 2012Mar 01 2012We observe that an analogue of the Positive Mass Theorem in the time-symmetric case for three-space-time-dimensional general relativity follows trivially from the Gauss-Bonnet theorem. In this case we also have that the spatial slice is diffeomorphic ... More
Applications of differential algebra to algebraic independence of arithmetic functionsApr 10 2015Jan 16 2017We generalize and unify the proofs of several results on algebraic in- dependence of arithmetic functions and Dirichlet series by a theorem of Ax on differential Schanuel conjecture. Along the way, we find counter-examples to some results in the literature. ... More
SignEPC : A Digital Signature Scheme for Efficient and Scalable Access Control in EPCglobal NetworkSep 18 2015The EPCglobal network is a computer network which allows supply chain companies to search for their unknown partners globally and share information stored in product RFID tags with each other. Although there have been quite a number of recent research ... More
Non-equilibrium Transport in the Strange Metal and Pseudogap phases of the CupratesAug 21 2013We propose that the non-equilibrium current measured in the $a-b$ plane of an underdoped cuprate (in either the strange metal or pseudogap regime) in contact with either an overdoped cuprate or a standard Fermi liquid can be used diagnose how different ... More
A Systematic Scheme for Measuring the Performance of the Display-Camera ChannelJan 12 2015Display-camera communication has become a promising direction in both computer vision and wireless communication communities. However, the consistency of the channel measurement is an open issue since precise calibration of the experimental setting has ... More
Coarsening to Chaos-Stabilized FrontsJun 01 2010We investigate a model for pattern formation in the presence of Galilean symmetry proposed by Matthews and Cox [Phys.\ Rev.\ E \textbf{62}, R1473 (2000)], which has the form of coupled generalized Burgers and Ginzburg-Landau-type equations. With only ... More
Spin Glass Transition at Nonzero Temperature in a Disordered Dipolar Ising System: The Case of LiHoxY{1-x}F4Oct 05 2008Jul 20 2009The physics of the spin glass (SG) state, with magnetic moments (spins) frozen in random orientations, is one of the most intriguing problems in condensed matter physics. While most theoretical studies have focused on the Edwards-Anderson model of Ising ... More
Nowhere-zero flows in signed graphs: A surveyAug 24 2016We survey known results related to nowhere-zero flows and related topics, such as circuit covers and the structure of circuits of signed graphs. We include an overview of several different definitions of signed graph colouring.
Shape transitions in proton-neutron systemsDec 11 1996We explore the possibility of shape transitions in proton-neutron systems driven by deformation differences between proton and neutron fluids. Within the framework of the proton-neutron interacting boson model, we show that such dynamic shape transitions ... More
Anomalous Scaling on a Spatiotemporally Chaotic AttractorJun 01 2010The Nikolaevskiy model for pattern formation with continuous symmetry exhibits spatiotemporal chaos with strong scale separation. Extensive numerical investigations of the chaotic attractor reveal unexpected scaling behavior of the long-wave modes. Surprisingly, ... More
Spectrality of Self-Similar TilesSep 16 2013We call a set $K \subset {\mathbb R}^s$ with positive Lebesgue measure a {\it spectral set} if $L^2(K)$ admits an exponential orthonormal basis. It was conjectured that $K$ is a spectral set if and only if $K$ is a tile (Fuglede's conjecture). Despite ... More
Temperature Dependence of Violation of Bell's Inequality in Coupled Quantum Dots in a MicrocavityMay 22 2007Bell's inequality in two coupled quantum dots within cavity QED, including Forster and exciton-phonon interactions, is investigated theoretically. It is shown that the environmental temperature has a significant impact on Bell's inequality.
Critical exponents of induced Dirichlet forms on self-similar setsDec 06 2016In a previous paper, we studied certain random walks on the hyperbolic graphs $X$ associated with the self-similar sets $K$, and showed that the discrete energy ${\mathcal E}_X$ on $X$ has an induced energy form ${\mathcal E}_K$ on $K$. The domain of ... More
Realizing a Four-Step Molecular Switch in Scanning Tunneling Microscope Manipulation of Single Chlorophyll-a MoleculesSep 05 2006Single chlorophyll-a molecules, a vital resource for the sustenance of life on Earth, have been investigated by using scanning-tunneling-microscope manipulation and spectroscopy on a gold substrate at 4.6 K. The chlorophyll-a binds on Au(111) via its ... More
Small zeros of hermitian forms over a quaternion algebraNov 20 2009Let $D$ be a positive definite quaternion algebra over a totally real number field $K$, $F(X,Y)$ a hermitian form in 2N variables over $D$, and $Z$ a right $D$-vector space which is isotropic with respect to $F$. We prove the existence of a small-height ... More
SUSY-Induced CP Violation in $t$ Decays at $e^-e^+$ CollidersJun 28 1993Jun 04 1998CP violation in the decays $t \to \ell^+\nu b$ and $\bar t \to \ell^-\bar\nu \bar b$ from the production process $e^-e^+ \to \ttbar$ is discussed. Since the asymmetry proposed as a measure of CP violation vanishes even at the one-loop level in the Standard ... More
Diffuse inverse Compton and synchrotron emission from dark matter annihilations in galactic satellitesMar 22 2004Annihilating dark matter particles produce roughly as much power in electrons and positrons as in gamma ray photons. The charged particles lose essentially all of their energy to inverse Compton and synchrotron processes in the galactic environment. We ... More
Superheavy Particle Origin of IceCube PeV Neutrino EventsMay 29 2013Oct 26 2013We interpret the PeV shower events observed by the IceCube collaboration as an s-channel enhancement of neutrino-quark scattering by a leptoquark that couples to the tau-flavor and light quarks. With a leptoquark mass of ~ 0.6 TeV and a steep 1/E^{2.3} ... More
Linked and knotted chimera filaments in oscillatory systemsSep 08 2015Jul 17 2016While the existence of stable knotted and linked vortex lines has been established in many experimental and theoretical systems, their existence in oscillatory systems and systems with nonlocal coupling has remained elusive. Here, we present strong numerical ... More
Quadratic Gravitational Lagrangian with Torsion Can Give Possible Explanations of the Form of Galactic Rotation Curves, of the Amount of Intergalactic Lensings, and of the Accelerating Expansion of the UniverseNov 30 2011Jan 16 2012The Quadratic Gravitational Lagrangian with torsion provides us with a richer number of solutions than the Einstein-Hilbert Lagrangian does. With proper interpretation, these solutions, together, seem to give good explanations of the form of the galactic ... More
Supersymmetric Sine-Gordon Model and the Eight-Vertex Free Fermion model with BoundaryJun 03 1996Jun 30 1996We compute the boundary scattering amplitudes of the breathers of the supersymmetric sine-Gordon model using the fusion of the soliton-antisoliton pair scattering with the boundary with a known result of the soliton boundary scattering amplitudes. We ... More
Detection and construction of an elliptic solution to the complex cubic-quintic Ginzburg-Landau equationApr 13 2012In evolution equations for a complex amplitude, the phase obeys a much more intricate equation than the amplitude. Nevertheless, general methods should be applicable to both variables. On the example of the traveling wave reduction of the complex cubic-quintic ... More
Holomorphic vector fields and quadratic differentials on planar triangular meshesJun 26 2015Nov 12 2015Given a triangulated region in the complex plane, a discrete vector field $Y$ assigns a vector $Y_i\in \mathbb{C}$ to every vertex. We call such a vector field holomorphic if it defines an infinitesimal deformation of the triangulation that preserves ... More
Spontaneously Broken Erlangen Program Offers a Bridge Between the Einstein and the Yang-Mills TheoriesMay 11 2012Nov 26 2012We shall give dynamics to our spacetime manifold by first identifying the local affine symmetry as the characterizing symmetry for our geometry \'a la Felix Klein, and then by prescribing 16 gauge vector bosons to this symmetry \'a la Yang and Mills. ... More
Dips at CollidersJul 23 2014Aug 14 2014We categorize new physics signatures that manifest themselves as a "dip" structure at colliders. One potential way to realize a dip is to require interactions to be zero when all particles are mass on-shell, but not if one or more are mass off-shell. ... More
On differential characteristic classesNov 15 2013Oct 16 2014In this paper we give explicit formulas of differential characteristic classes of principal $G$-bundles with connections and prove their expected properties. In particular, we obtain explicit formulas for differential Chern classes, differential Pontryagin ... More
Time complexity of concurrent programsNov 16 2015We study the problem of automatically computing the time complexity of concurrent object-oriented programs. To determine this complexity we use intermediate abstract descriptions that record relevant information for the time analysis (cost of statements, ... More
Landmark-matching Transformation with Large Deformation via n-dimensional Quasi-conformal MapsFeb 27 2014May 11 2015We propose a new method to obtain landmark-matching transformations between n-dimensional Euclidean spaces with large deformations. Given a set of feature correspondences, our algorithm searches for an optimal folding-free mapping that satisfies the prescribed ... More
Multifractal characterisation of length sequences of coding and noncoding segments in a complete genomeAug 28 2001The coding and noncoding length sequences constructed from a complete genome are characterised by multifractal analysis. The dimension spectrum $D_{q}$ and its derivative, the 'analogous' specific heat $C_{q}$, are calculated for the coding and noncoding ... More
Functional Renormalization Group Analysis of the Half-filled One-dimensional Extended Hubbard ModelMay 16 2005Feb 14 2006We study the phase diagram of the half-filled one-dimensional extended Hubbard model at weak coupling using a novel functional renormalization group (FRG) approach. The FRG method includes in a systematic manner the effects of the scattering processes ... More
On an index theorem by BismutJan 07 2015Jul 16 2015In this paper we give a proof of an index theorem by Bismut. As a consequence we obtain another proof of the Grothendieck-Riemann-Roch theorem in differential cohomology.
Estimation in a semiparametric modulated renewal processNov 21 2005We consider parameter estimation in a regression model corresponding to an iid sequence of censored observations of a finite state modulated renewal process. The model assumes a similar form as in Cox regression except that the baseline intensities are ... More
A Quadratic Programming Relaxation Approach to Compute-and-Forward Network Coding DesignJul 07 2016Using physical layer network coding, compute-and-forward is a promising relaying scheme that effectively exploits the interference between users and thus achieves high rates. In this paper, we consider the problem of finding the optimal integer-valued ... More
Small coherence implies the weak Null Space PropertyJun 29 2016In the Compressed Sensing community, it is well known that given a matrix $X \in \mathbb R^{n\times p}$ with $\ell_2$ normalized columns, the Restricted Isometry Property (RIP) implies the Null Space Property (NSP). It is also well known that a small ... More
Tilings of the Sphere by Edge Congruent PentagonsJan 04 2013Apr 14 2013We study edge-to-edge tilings of the sphere by edge congruent pentagons, under the assumption that there are tiles with all vertices having degree 3. We develop the technique of neighborhood tilings and apply the technique to completely classify edge ... More
Perverse Sheaves and Knot Contact HomologyOct 07 2016In this paper, which is mostly a research announcement, we give a new algebraic construction of knot contact homology in the sense of L. Ng [Ng05a]. For a link $L$ in $ {\mathbb R}^3 $, we define a differential graded (DG) $k$-category $ \tilde{\mathscr ... More
Signal of Theta^+ in quenched lattice QCD with exact chiral symmetryJan 25 2005We investigate the mass spectrum of the pentaquark baryon ($ udud \bar s $) in quenched lattice QCD with exact chiral symmetry. Using 3 different interpolating operators, we measure their $ 3 \times 3 $ correlation matrix and obtain the eigenvalues $ ... More
Spin Dependence of Dark Matter ScatteringJun 11 2008New experiments designed to discover a weakly interacting dark matter (DM) particle via spin dependent scattering can distinguish models of electroweak symmetry breaking. The plane of spin dependent versus spin independent DM scattering cross sections ... More
Hydrodynamic Limits and Propagation of Chaos for Interacting Random Walks in DomainsNov 11 2013Jan 29 2014A new non-conservative stochastic reaction-diffusion system in which two families of random walks in two adjacent domains interact near the interface is introduced and studied in this paper. Such a system can be used to model the transport of positive ... More
Wronskians and Linear Dependence of Formal Power SeriesOct 29 2016We give a new proof of the fact that the vanishing of generalized Wronskians implies linear dependence of formal power series in serveral variables. Our results are also valid for quotients of germs of analytic functions.
Large Deviations for Brownian Particle Systems with KillingSep 11 2016Particle approximations for certain nonlinear and nonlocal reaction-diffusion equations are studied using a system of Brownian motions with killing. The system is described by a collection of i.i.d. Brownian particles where each particle is killed independently ... More
Properties of the multiway discrepancySep 26 2016Some properties of the multiway discrepanc of rectangular matrices of nonnegative entries are discussed. We are able to prove the continuity of this discrepancy, as well as some statements about the multiway discrepancy of some special matrices and graphs. ... More
Asymptotics for $2D$ Critical First Passage PercolationMay 28 2015Aug 15 2015We consider first-passage percolation on $\mathbb{Z}^2$ with i.i.d. weights, whose distribution function satisfies $F(0) = p_c = 1/2$. This is sometimes known as the "critical case" because large clusters of zero-weight edges force passage times to grow ... More
Matroid Online Bipartite Matching and Vertex CoverJun 25 2016The Adwords and Online Bipartite Matching problems have enjoyed a renewed attention over the past decade due to their connection to Internet advertising. Our community has contributed, among other things, new models (notably stochastic) and extensions ... More
Accuracy of Semiclassical Methods for Shape Invariant PotentialsNov 18 1996We study the accuracy of several alternative semiclassical methods by computing analytically the energy levels for many large classes of exactly solvable shape invariant potentials. For these potentials, the ground state energies computed via the WKB ... More
Blowup of Regular Solutions for the Relativistic Euler-Poisson EquationsSep 04 2015In this paper, we study the blowup phenomena for the regular solutions of the isentropic relativistic Euler-Poisson equations with a vacuum state in spherical symmetry. Using a general family of testing functions, we obtain new blowup conditions for the ... More
Chimera patterns in conservative systems and ultracold atoms with mediated nonlocal hoppingAug 15 2017Chimera patterns, characterized by coexisting regions of phase coherence and incoherence, have so far been studied in non-conservative systems with dissipation. Here, we show that the formation of chimera patterns can also be observed in conservative ... More
Active Sensing of Social NetworksJan 21 2016This paper develops an active sensing method to estimate the relative weight (or trust) agents place on their neighbors' information in a social network. The model used for the regression is based on the steady state equation in the linear DeGroot model ... More
Triple-Top Signal of New Physics at the LHCJan 04 2010Dec 01 2010We present leading-order (LO) cross sections for the production of three top quarks ($tt\tb$,$t\tb\tb$) at the Large Hadron Collider (LHC). We find a total LO cross section for triple-top production in the Standard Model of $\sigma \approx 2 $ fb at $\sqrt{s}=14$ ... More
Azimuthal Correlations in Top Pair Decays and The Effects of New Heavy ScalarsDec 21 2011Mar 08 2012We present the azimuthal correlations in the decay products of the top quark pair created in the process $gg \to t \tbar \to b \bbar \wplus \wminus$ calculated in leading-order QCD. We then discuss deviations in this distribution that could arise from ... More
Computing Walrasian Equilibria: Fast Algorithms and Structural PropertiesNov 12 2015Apr 05 2016We present the first polynomial time algorithm for computing Walrasian equilibrium in an economy with indivisible goods and \emph{general} buyer valuations having only access to an \emph{aggregate demand oracle}, i.e., an oracle that given prices on all ... More
Graph Sparsification by Edge-Connectivity and Random Spanning TreesMay 03 2010Aug 09 2010We present new approaches to constructing graph sparsifiers --- weighted subgraphs for which every cut has the same value as the original graph, up to a factor of $(1 \pm \epsilon)$. Our first approach independently samples each edge $uv$ with probability ... More
CP--odd Correlation in the Decay of Neutral Higgs Boson into $ZZ$, $W^+W^-$, or $t{\bar t}$Mar 05 1993Jun 16 1998We investigate the possibility of detecting CP--odd angular correlations in the various decay modes of the neutral Higgs boson including the modes of a $ZZ$ pair, a $W^+W^-$ pair, or a heavy quark pair. It is a natural way to probe the CP character of ... More
CP Violation in top pair production at an e^+e^- colliderJan 22 1993Jun 14 1998We investigate possible CP violating effects in $e^+e^-$ annihilation into top quark pairs. One of the interesting observable effects is the difference in production rates between the two CP conjugate polarized states $t_L\bar t_L$ and $t_R\bar t_R$. ... More
Architecture of an Open-Sourced, Extensible Data Warehouse Builder: InterBase 6 Data Warehouse Builder (IB-DWB)Jul 07 2003Jun 10 2006We report the development of an open-sourced data warehouse builder, InterBase Data Warehouse Builder (IB-DWB), based on Borland InterBase 6 Open Edition Database Server. InterBase 6 is used for its low maintenance and small footprint. IB-DWB is designed ... More
Properties of a magnetic superconductor with weak magnetization - application to $ErNi_2B_2C$Oct 20 2000Using a Ginsburg-Landau free energy functional, we study the $H-T$ phase diagram of a weak magnetic superconductor, where the magnetization from the magnetic component is marginal in supporting a spontaneous vortex phase in absence of external magnetic ... More
On the wavelets-based SWIFT method for backward stochastic differential equationsNov 09 2016We propose a numerical algorithm for backward stochastic differential equations based on time discretization and trigonometric wavelets. This method combines the effectiveness of Fourier-based methods and the simplicity of a wavelet-based formula, resulting ... More
Warped Product Space-timesJul 05 2017Many classical results in relativity theory concerning spherically symmetric space-times have easy generalizations to warped product space-times, with a two-dimensional Lorentzian base and arbitrary dimensional Riemannian fibers. We first give a systematic ... More
An existence time estimate for Kähler-Ricci flowAug 14 2015Mar 23 2016Fix a complete noncompact \K manifold $(M^n,h_0)$ with bounded curvature. Let $g(t)$ be a bounded curvature solution to the \KR flow starting from some $g_0$ uniformly equivalent to $h_0$. We estimate the existence time of $g(t)$ together with $C^0$ bounds ... More
Thermodynamic Spin Glass Phase Induced by Weak Random Exchange Disorder in a Classical Spin Liquid: the Case of the Pyrochlore Heisenberg AntiferromagnetSep 07 2010The glassy behavior observed in the pyrochlore magnet Y2Mo2O7, where the magnetic Mo^{4+} ions interact predominantly via isotropic nearest neighbor antiferromagnetic exchange, possibly with additional weak disorder, is a distinct class of spin glass ... More
On Iwasawa Theory over Function FieldsJan 02 2007Let $k_{\infty}$ be a $\Z_p^d$-extension of a global function field $k$ of characteristic $p$. Let $\Cl_{k_{\infty},p}$ be the $p$ completion of the class group of $k_{\infty}$. We prove that the characteristic ideal of the Galois module $\Cl_{k_{\infty},p}$ ... More
Reversible Superconductivity in Electrochromic Indium-Tin Oxide FilmsMar 21 2012Oct 09 2012Transparent conductive indium tin oxide (ITO) thin films, electrochemically intercalated with sodium or other cations, show tunable superconducting transitions with a maximum $T_c$ at 5 K. The transition temperature and the density of states, $D(E_F)$ ... More
Modeling Deployment Decisions for Elastic Services with ABSOct 26 2016The use of cloud technology can offer significant savings for the deployment of services, provided that the service is able to make efficient use of the available virtual resources to meet service-level requirements. To avoid software designs that scale ... More
Young, UV-bright Stars Dominate Dust Heating in Star Forming GalaxiesJun 10 2011In star forming galaxies, dust plays a significant role in shaping the ultraviolet (UV) through infrared (IR) spectrum. Dust attenuates the radiation from stars, and re-radiates the energy through equilibrium and non-equilibrium emission. Polycyclic aromatic ... More
Geometric phase of a central spin coupled to an antiferromagnetic environmentMar 05 2010Using the spin-wave approximation, we study the geometric phase (GP) of a central spin (signal qubit) coupled to an antiferromagnetic (AF) environment under the application of an external global magnetic field. The external magnetic field affects the ... More