Results for "Andrew M. Dai"

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The supervised hierarchical Dirichlet processDec 17 2014We propose the supervised hierarchical Dirichlet process (sHDP), a nonparametric generative model for the joint distribution of a group of observations and a response variable directly associated with that whole group. We compare the sHDP with another ... More
Virtual Adversarial Training for Semi-Supervised Text ClassificationMay 25 2016Adversarial training provides a means of regularizing supervised learning algorithms while virtual adversarial training is able to extend supervised learning algorithms to the semi-supervised setting. However, both methods require making small perturbations ... More
Semi-supervised Sequence LearningNov 04 2015We present two approaches that use unlabeled data to improve sequence learning with recurrent networks. The first approach is to predict what comes next in a sequence, which is a conventional language model in natural language processing. The second approach ... More
MaskGAN: Better Text Generation via Filling in the ______Jan 23 2018Neural text generation models are often autoregressive language models or seq2seq models. These models generate text by sampling words sequentially, with each word conditioned on the previous word, and are state-of-the-art for several machine translation ... More
Adversarial Training Methods for Semi-Supervised Text ClassificationMay 25 2016Nov 07 2016Adversarial training provides a means of regularizing supervised learning algorithms while virtual adversarial training is able to extend supervised learning algorithms to the semi-supervised setting. However, both methods require making small perturbations ... More
Millimeter Dust Emission in the GQ Lup SystemDec 12 2009We present Submillimeter Array observations of the GQ Lup system at 1.3 millimeters wavelength with $0\farcs4$ ($\sim$60 AU) resolution. Emission is detected from the position of the primary star, GQ Lup A, and is marginally resolved. No emission is detected ... More
Document Embedding with Paragraph VectorsJul 29 2015Paragraph Vectors has been recently proposed as an unsupervised method for learning distributed representations for pieces of texts. In their work, the authors showed that the method can learn an embedding of movie review texts which can be leveraged ... More
Many Paths to Equilibrium: GANs Do Not Need to Decrease a Divergence At Every StepOct 23 2017Feb 20 2018Generative adversarial networks (GANs) are a family of generative models that do not minimize a single training criterion. Unlike other generative models, the data distribution is learned via a game between a generator (the generative model) and a discriminator ... More
Embedding Text in Hyperbolic SpacesJun 12 2018Natural language text exhibits hierarchical structure in a variety of respects. Ideally, we could incorporate our prior knowledge of this hierarchical structure into unsupervised learning algorithms that work on text data. Recent work by Nickel & Kiela ... More
Graph Convolutional Transformer: Learning the Graphical Structure of Electronic Health RecordsJun 11 2019Effective modeling of electronic health records (EHR) is rapidly becoming an important topic in both academia and industry. A recent study showed that utilizing the graphical structure underlying EHR data (e.g. relationship between diagnoses and treatments) ... More
Generating Sentences from a Continuous SpaceNov 19 2015May 12 2016The standard recurrent neural network language model (RNNLM) generates sentences one word at a time and does not work from an explicit global sentence representation. In this work, we introduce and study an RNN-based variational autoencoder generative ... More
Who Said What: Modeling Individual Labelers Improves ClassificationMar 26 2017Jan 04 2018Data are often labeled by many different experts with each expert only labeling a small fraction of the data and each data point being labeled by several experts. This reduces the workload on individual experts and also gives a better estimate of the ... More
Phospholipid-Dextran with a Single Coupling Point: a Useful Amphiphile for Functionalization of NanomaterialsJan 31 2009Nanomaterials hold much promise for biological applications, but they require appropriate functionalization to provide biocompatibility in biological environments. For non-covalent functionalization with biocompatible polymers, the polymer must also remain ... More
Learning Longer-term Dependencies in RNNs with Auxiliary LossesMar 01 2018Jun 13 2018Despite recent advances in training recurrent neural networks (RNNs), capturing long-term dependencies in sequences remains a fundamental challenge. Most approaches use backpropagation through time (BPTT), which is difficult to scale to very long sequences. ... More
HyperNetworksSep 27 2016Dec 01 2016This work explores hypernetworks: an approach of using a one network, also known as a hypernetwork, to generate the weights for another network. Hypernetworks provide an abstraction that is similar to what is found in nature: the relationship between ... More
HyperNetworksSep 27 2016Oct 28 2016This work explores hypernetworks: an approach of using a one network, also known as a hypernetwork, to generate the weights for another network. Hypernetworks provide an abstraction that is similar to what is found in nature: the relationship between ... More
HyperNetworksSep 27 2016This work explores hypernetworks: an approach of using a small network, also known as a hypernetwork, to generate the weights for a larger network. Hypernetworks provide an abstraction that is similar to what is found in nature: the relationship between ... More
PEG Branched Polymer for Functionalization of Nanomaterials with Ultralong Blood CirculationJan 30 2009Nanomaterials have been actively pursued for biological and medical applications in recent years. Here, we report the synthesis of several new poly(ethylene glycol) grafted branched-polymers for functionalization of various nanomaterials including carbon ... More
Analyzing the Role of Model Uncertainty for Electronic Health RecordsJun 10 2019In medicine, both ethical and monetary costs of incorrect predictions can be significant, and the complexity of the problems often necessitates increasingly complex models. Recent work has shown that changing just the random seed is enough for otherwise ... More
ALMA Measurements of Circumstellar Material in the GQ Lup SystemNov 18 2016We present ALMA observations of the GQ Lup system, a young Sun-like star with a substellar mass companion in a wide-separation orbit. These observations of 870 $\mu$m continuum and CO J=3-2 line emission with beam size $\sim0.3''$ ($\sim45$ AU) resolve ... More
Gmail Smart Compose: Real-Time Assisted WritingMay 17 2019In this paper, we present Smart Compose, a novel system for generating interactive, real-time suggestions in Gmail that assists users in writing mails by reducing repetitive typing. In the design and deployment of such a large-scale and complicated system, ... More
Peptide-Spectra Matching from Weak SupervisionAug 20 2018Aug 22 2018As in many other scientific domains, we face a fundamental problem when using machine learning to identify proteins from mass spectrometry data: large ground truth datasets mapping inputs to correct outputs are extremely difficult to obtain. Instead, ... More
One-Parameter Scaling of the Conductivity of Si:B: A Temperature-Independent Variable-Range Hopping PrefactorSep 12 2001For insulating Si:B with dopant concentrations from 0.75 n_c to the critical concentration n_c, the conductivity ranging over five orders of magnitude collapses using a single scaling parameter T* onto a universal curve of the form $\sigma (T) =\sigma_0 ... More
Music TransformerSep 12 2018Dec 12 2018Music relies heavily on repetition to build structure and meaning. Self-reference occurs on multiple timescales, from motifs to phrases to reusing of entire sections of music, such as in pieces with ABA structure. The Transformer (Vaswani et al., 2017), ... More
Fully distributed PageRank computation with exponential convergenceMay 28 2017Oct 22 2018This work studies a fully distributed algorithm for computing the PageRank vector, which is inspired by the Matching Pursuit and features: 1) a fully distributed implementation 2) convergence in expectation with exponential rate 3) low storage requirement ... More
Dynamics of a producer-parasite ecosystem on the brink of collapseJun 14 2013Ecosystems can undergo sudden shifts to undesirable states, but recent studies with simple single species ecosystems have demonstrated that advance warning can be provided by the slowing down of population dynamics near a tipping point. However, it is ... More
Low RF-Complexity Technologies for 5G Millimeter-Wave MIMO Systems with Large Antenna ArraysJul 15 2016Millimeter-wave (mmWave) MIMO with large antenna array has attracted considerable interests from academic and industry, as it can simultaneously provide wider bandwidth and higher spectrum efficiency. However, with hundreds of antennas employed at mmWave ... More
On Super-Resolution in Multirate Sampling SystemsSep 11 2016Oct 06 2016Super-resolution theory aims to estimate the discrete components lying in a continuous space that constitute a sparse signal with optimal precision. This work investigates the potential of recent super-resolution techniques for spectral estimation in ... More
Production of the Extreme-Ultraviolet Late Phase of an X Class Flare in a Three-Stage Magnetic Reconnection ProcessJul 18 2013We report observations of an X class flare on 2011 September 6 by the instruments onboard the Solar Dynamics Observatory (SDO). The flare occurs in a complex active region with multiple polarities. The Extreme-Ultraviolet (EUV) Variability Experiment ... More
Low RF-Complexity Technologies to Enable Millimeter-Wave MIMO with Large Antenna Array for 5G Wireless CommunicationsJul 15 2016Oct 01 2017Millimeter-wave (mmWave) MIMO with large antenna array has attracted considerable interests from academic and industry communities, as it can provide larger bandwidth and higher spectrum efficiency. However, with hundreds of antennas, the number of radio ... More
$Suzaku$ Measurements of Hot Halo Emission at Outskirts for Two Poor Galaxy Groups: NGC 3402 and NGC 5129Apr 26 2017We present $Suzaku$ off-center observations of two poor galaxy groups, NGC 3402 and NGC 5129, with temperatures below 1 keV. Through spectral decomposition, we measure their surface brightnesses and temperatures out to 330 and 680 times the critical density ... More
Efficient fault-tolerant quantum computingSep 17 1998Sep 18 1998Fault tolerant quantum computing methods which work with efficient quantum error correcting codes are discussed. Several new techniques are introduced to restrict accumulation of errors before or during the recovery. Classes of eligible quantum codes ... More
The Star Formation History of the UniverseNov 09 2006Strong constraints on the cosmic star formation history (SFH) have recently been established using ultraviolet and far-infrared measurements, refining the results of numerous measurements over the past decade. Taken together, the most recent and robust ... More
The fields and self-force of a constantly accelerating spherical shellJul 18 2013We present a partial differential equation describing the electromagnetic potentials around a charge distribution undergoing rigid motion at constant proper acceleration, and obtain a set of solutions to this equation. These solutions are used to find ... More
Gromov hyperbolicity, the Kobayashi metric, and $\mathbb{C}$-convex setsFeb 03 2016In this paper we study the global geometry of the Kobayashi metric on domains in complex Euclidean space. We are particularly interested in developing necessary and sufficient conditions for the Kobayashi metric to be Gromov hyperbolic. For general domains, ... More
Gromov hyperbolicity and the Kobayashi metric on convex domains of finite typeMay 12 2014Aug 21 2015In this paper we prove necessary and sufficient conditions for the Kobayashi metric on a convex domain to be Gromov hyperbolic. In particular we show that for convex domains with $C^\infty$ boundary being of finite type in the sense of D'Angelo is equivalent ... More
Refining enumeration schemes to count according to permutation statisticsJan 01 2014We consider the question of computing the distribution of a permutation statistics over restricted permutations via enumeration schemes. The restricted permutations are those avoiding sets of vincular patterns (which include both classical and consecutive ... More
Compact asymptotically harmonic manifoldsMay 10 2012Oct 16 2012A complete Riemannian manifold without conjugate points is called asymptotically harmonic if the mean curvature of its horospheres is a universal constant. Examples of asymptotically harmonic manifolds include flat spaces and rank one locally symmetric ... More
Achieving Super-Resolution in Multi-Rate Sampling Systems via Efficient Semidefinite ProgrammingApr 19 2016Aug 02 2016Super-resolution theory aims to estimate the discrete components lying in a continuous space that constitute a sparse signal with optimal precision. This work investigates the potential of recent super-resolution techniques for spectral estimation in ... More
Two photon couplings of the lightest isoscalars from BELLE dataMar 28 2014Jul 03 2014Amplitude Analysis of two photon production of $\pi\pi$ and ${\overline K}K$, using S-matrix constraints and fitting all available data, including the latest precision results from Belle, yields a single partial wave solution up to 1.4 GeV. The two photon ... More
An Equivalent Presentation of the Bezem-Coquand-Huber Category of Cubical SetsJan 30 2014Staton has shown that there is an equivalence between the category of presheaves on (the opposite of) finite sets and partial bijections and the category of nominal restriction sets: see [2, Exercise 9.7]. The aim here is to see that this extends to an ... More
Minimal and irreducible links in the Shannon gameJan 28 2013We discuss weak and strong links (`virtual connections') in the Shannon game. General properties of these links are discussed, leading to a method to find all links of given size by a suitably pruned exhaustive search. This is applied to links on graphs ... More
Quantum computer architecture for fast entropy extractionMar 11 2002If a quantum computer is stabilized by fault-tolerant quantum error correction (QEC), then most of its resources (qubits and operations) are dedicated to the extraction of error information. Analysis of this process leads to a set of central requirements ... More
The Ion Trap Quantum Information ProcessorAug 08 1996Aug 09 1996An introductory review of the linear ion trap is given, with particular regard to its use for quantum information processing. The discussion aims to bring together ideas from information theory and experimental ion trapping, to provide a resource to workers ... More
Observations of Solids in Protoplanetary DisksJul 16 2015This review addresses the state of research that employs astronomical (remote sensing) observations of solids ("dust") in young circumstellar disks to learn about planet formation. The intention is for it to serve as an accessible, introductory, pedagogical ... More
Characterizing polynomial domains by their automorphism groupJun 25 2015In this paper we study the automorphism group of bounded convex domains with smooth boundary. In particular, we show that such a domain is biholomorphic to a weighted homogeneous polynomial domain if and only if the limit set of the automorphism group ... More
Graph reconstruction and generation from one card and the degree sequenceOct 05 2018Many degree sequences can only be realised in graphs that contain a `ds-completable card', defined as a vertex-deleted subgraph in which the erstwhile neighbours of the deleted vertex can be identified from their degrees, if one knows the degree sequence ... More
On the relationship between continuous- and discrete-time quantum walkOct 01 2008Oct 21 2009Quantum walk is one of the main tools for quantum algorithms. Defined by analogy to classical random walk, a quantum walk is a time-homogeneous quantum process on a graph. Both random and quantum walks can be defined either in continuous or discrete time. ... More
An introduction to spinorsDec 13 2013We introduce spinors, at a level appropriate for an undergraduate or first year graduate course on relativity, astrophysics or particle physics. The treatment assumes very little mathematical knowledge (mainly just vector analysis and some idea of what ... More
Characterizing the unit ball by its projective automorphism groupJun 30 2015In this paper we study the projective automorphism group of domains in real, complex, and quaternionic projective space and present two new characterizations of the unit ball in terms of the size of the automorphism group and the regularity of the boundary. ... More
H-Matrix and Block Error TolerancesOct 12 2011We describe a new method to map the requested error tolerance on an H-matrix approximation to the block error tolerances. Numerical experiments show that the method produces more efficient approximations than the standard method for kernels having singularity ... More
The non-existence of the self-accelerating dipole, and related questionsNov 22 2013Mar 19 2014We calculate the self-force of a constantly accelerating electric dipole, showing, in particular, that classical electromagnetism does not predict that an electric dipole could self-accelerate, nor could it levitate in a gravitational field. We also resolve ... More
Reduced-order Abraham-Lorentz-Dirac equation and the consistency of classical electromagnetismFeb 05 2014Jul 22 2014It is widely believed that classical electromagnetism is either unphysical or inconsistent, owing to pathological behavior when self-force and radiation reaction are non-negligible. We argue that there is no inconsistency as long as it is recognized that ... More
Context, spacetime loops, and the interpretation of quantum mechanicsNov 03 2006Three postulates are discussed: first that well-defined properties cannot be assigned to an isolated system, secondly that quantum unitary evolution is atemporal, and thirdly that some physical processes are never reversed. It is argued that these give ... More
How to build a 300 bit, 1 Giga-operation quantum computerDec 21 2004Sep 01 2006Experimental methods for laser-control of trapped ions have reached sufficient maturity that it is possible to set out in detail a design for a large quantum computer based on such methods, without any major omissions or uncertainties. The main features ... More
Fast fault-tolerant filtering of quantum codewordsFeb 06 2002Apr 02 2004The stabilization of a quantum computer by repeated error correction can be reduced almost entirely to repeated preparation of blocks of qubits in quantum codeword states. These are multi-particle entangled states with a high degree of symmetry. The required ... More
Boundaries of non-compact harmonic manifoldsAug 23 2012Dec 16 2012In this paper we consider non-compact non-flat simply connected harmonic manifolds. In particular, we show that the Martin boundary and Busemann boundary coincide for such manifolds. For any finite volume quotient we show that (up to scaling) there is ... More
UHECR Composition ModelsDec 31 2013In light of the increasingly heavy UHECR composition at the highest energies, as observed by the Pierre Auger Observatory, the implications of these results on the actual source composition and spectra are investigated. Depending on the maximum energy ... More
Rigidity of complex convex divisible setsAug 19 2013An open convex set in real projective space is called divisible if there exists a discrete group of projective automorphisms which acts co-compactly. There are many examples of such sets and a theorem of Benoist implies that many of these examples are ... More
Shape-Wilf-equivalences for vincular patternsJan 23 2012Feb 02 2013We extend the notion of shape-Wilf-equivalence to vincular patterns (also known as "generalized patterns" or "dashed patterns"). First we introduce a stronger equivalence on patterns which we call filling-shape-Wilf-equivalence. When vincular patterns ... More
Characterizing domains by the limit set of their automorphism groupJun 25 2015Jan 14 2017In this paper we study the automorphism group of smoothly bounded convex domains. We show that such a domain is biholomorphic to a "polynomial ellipsoid" (that is, a domain defined by a weighted homogeneous balanced polynomial) if and only if the limit ... More
Pfaffian States in Coupled Atom-Cavity SystemsMar 08 2016Coupled atom-cavity arrays, such as those described by the Jaynes-Cummings Hubbard model, have the potential to emulate a wide range of condensed matter phenomena. In particular, the strongly correlated states of the fractional quantum Hall effect can ... More
Extended Inflation with a Curvature-Coupled InflatonJun 30 1993Dec 20 1993We examine extended inflation models enhanced by the addition of a coupling between the inflaton field and the space-time curvature. We examine two types of model, where the underlying inflaton potential takes on second-order and first-order form respectively. ... More
Threat, support and dead edges in the Shannon gameOct 30 2012The notions of captured/lost vertices and dead edges in the Shannon game (Shannon switching game on nodes) are examined using graph theory. Simple methods are presented for identifying some dead edges and some captured sets of vertices, thus simplifying ... More
Overhead and noise threshold of fault-tolerant quantum error correctionJul 19 2002Jul 31 2003Fault tolerant quantum error correction (QEC) networks are studied by a combination of numerical and approximate analytical treatments. The probability of failure of the recovery operation is calculated for a variety of CSS codes, including large block ... More
Enlargement of Calderbank Shor Steane quantum codesFeb 24 1998Mar 31 1998It is shown that a classical error correcting code C = [n,k,d] which contains its dual, C^{\perp} \subseteq C, and which can be enlarged to C' = [n,k' > k+1, d'], can be converted into a quantum code of parameters [[ n, k+k' - n, min(d, 3d'/2) ]]. This ... More
Tracking the radiation reaction energy when charged bodies accelerateAug 06 2014We address some questions related to radiation and energy conservation in classical electromagnetism. We first treat the well-known problem of energy accounting during radiation from a uniformly accelerating particle. We present the problem in the form ... More
Π^0_1 classes, strong minimal covers and hyperimmune-free degreesNov 02 2007We investigate issues surrounding an old question of Yates' as to the existence of a minimal Turing degree with no strong minimal cover, specifically with respect to the hyperimmune-free degrees.
A New Method of Verification of Functional ProgramsApr 14 2016In the paper the problem of verification of functional programs (FPs) over strings is considered, where specifications of properties of FPs are defined by other FPs, and a FP S1 meets a specification defined by another FP S2 iff a composition of functions ... More
Theory of processesSep 12 2010The book gives a detailed exposition of basic concepts and results of a theory of processes. The presentation of theoretical concepts and results is accompanied with illustrations of their application to solving various problems of verification of processes. ... More
Secure assisted quantum computationNov 07 2001Jul 06 2005Suppose Alice wants to perform some computation that could be done quickly on a quantum computer, but she cannot do universal quantum computation. Bob can do universal quantum computation and claims he is willing to help, but Alice wants to be sure that ... More
Universal computation by quantum walkJun 12 2008In some of the earliest work on quantum mechanical computers, Feynman showed how to implement universal quantum computation by the dynamics of a time-independent Hamiltonian. I show that this remains possible even if the Hamiltonian is restricted to be ... More
Matter-wave coherence limit owing to cosmic gravitational wave backgroundOct 16 2017We study matter-wave interferometry in the presence of a stochastic background of gravitational waves. It is shown that if the background has a scale-invariant spectrum over a wide bandwidth (which is expected in a class of inflationary models of Big ... More
Structural Optimisation: Biomechanics of the FemurOct 06 2011Feb 20 2012A preliminary iterative 3D meso-scale structural model of the femur was developed, in which bar and shell elements were used to represent trabecular and cortical bone respectively. The cross-sectional areas of the bar elements and the thickness values ... More
A theory of probabilistic automata, part 1Jul 18 2015In the book we present main concepts of probabilistic automata theory.
Applying the Cluster Method to Count Occurrences of Generalized Permutation PatternsMay 29 2009We apply ideas from the cluster method to q-count the permutations of a multiset according to the number of occurrences of certain generalized patterns, as defined by Babson and Steingrimsson. In particular, we consider those patterns with three letters ... More
Asymptotically harmonic manifolds without focal pointsSep 12 2011Oct 06 2011In this note we show that a compact asymptotically harmonic manifold without focal points is either flat or a rank one locally symmetric space.
Protein Microarrays with Carbon Nanotubes as Multi-Color Raman LabelsOct 31 2008Detection of biomolecules is important in proteomics and clinical diagnosis and treatment of diseases. Here, we apply functionalized, macromolecular, single walled carbon nanotubes SWNTs as multi-color Raman labels to protein arrays for highly sensitive, ... More
On Super-Resolution in Multirate Sampling SystemsSep 11 2016Super-resolution theory aims to estimate the discrete components lying in a continuous space that constitute a sparse signal with optimal precision. This work investigates the potential of recent super-resolution techniques for spectral estimation in ... More
Pascalutsa-Vanderhaeghen light-by-light sumrule from photon-photon collisionsJan 16 2017Light-by-light scattering sumrules based on general field theory principles relate cross-sections with different helicities. In this paper the simplest sumrule is tested for the $I=0$ and $2$ channels for "real" photon-photon collisions. Important contributions ... More
Superfluid-Mott transitions and vortices in the Jaynes-Cummings-Hubbard lattices with time reversal symmetry breakingOct 20 2015We investigate the groundstate behaviour of Jaynes-Cummings-Hubbard lattices in the presence of a synthetic magnetic field, via a Gutzwiller ansatz. Specifically, we study the Mott-Superfluid transition, and the formation of vortex lattices in the superfluid ... More
Fractal Location and Anomalous Diffusion Dynamics for Oil Wells from the KY Geological SurveyDec 13 2009Utilizing data available from the Kentucky Geonet ( the fossil fuel mining locations created by the Kentucky Geological Survey geo-locating oil and gas wells are mapped using ESRI ArcGIS in Kentucky single plain 1602 ft projection. This ... More
Fractional Quantum Hall Physics in Jaynes-Cummings-Hubbard LatticesFeb 23 2012Jaynes-Cummings-Hubbard arrays provide unique opportunities for quantum emulation as they exhibit convenient state preparation and measurement, and in-situ tuning of parameters. We show how to realise strongly correlated states of light in Jaynes-Cummings-Hubbard ... More
Constraints on the Obliquities of Kepler Planet-Hosting StarsOct 12 2017Nov 24 2017Stars with hot Jupiters have obliquities ranging from 0-180 degrees, but relatively little is known about the obliquities of stars with smaller planets. Using data from the California-Kepler Survey, we investigate the obliquities of stars with planets ... More
Nano-Graphene Oxide for Cellular Imaging and Drug DeliveryAug 25 2008Two-dimensional graphene offers interesting electronic, thermal and mechanical properties that are currently explored for advanced electronics, membranes and composites. Here we synthesize and explore the biological application of nano-graphene oxide ... More
Analytic and Monte Carlo Studies of Jets with Heavy Mesons and QuarkoniaMar 22 2016Jun 16 2016We study jets with identified hadrons in which a family of jet-shape variables called angularities are measured, extending the concept of fragmenting jet functions (FJFs) to these observables. FJFs determine the fraction of energy, z, carried by an identified ... More
Near field thermal memory deviceAug 25 2014Nov 03 2014We report the concept of a near-field memory device based on the radiative bistability effect in the system of two closely separated parallel plates of SiO$_2$ and VO$_2$ which exchange heat by thermal radiation in vacuum. We demonstrate that the VO$_2$ ... More
On the existence of crepant resolutions of Gorenstein Abelian quotient singularities in dimensions \geq 4Dec 28 2005Apr 03 2006For which finite subgroups G of SL(r,C), r \geq 4, are there crepant desingularizations of the quotient space C^r/G? A complete answer to this question (also known as "Existence Problem" for such desingularizations) would classify all those groups for ... More
Local Structure and Macroscopic Properties in PMN-PT and PZN-PT solid solutionsOct 13 2004We have examined the local structure of PMN-PT and PZN-PT solid solutions using density functional theory. We find that the directions and magnitudes of cation displacement can be explained by an interplay of cation-oxygen bonding, electrostatic dipole-dipole ... More
Topological invariants for the fractional quantum Hall statesJan 16 2013We calculate a topological invariant, whose value would coincide with the Chern number in case of integer quantum Hall effect, for fractional quantum Hall states. In case of Abelian fractional quantum Hall states, this invariant is shown to be equal to ... More
Bulk-boundary correspondence of topological insulators from their Green's functionsApr 08 2011Aug 25 2011Topological insulators are noninteracting, gapped fermionic systems which have gapless boundary excitations. They are characterized by topological invariants, which can be written in many different ways, including in terms of Green's functions. Here we ... More
Minimizing the Aggregate Movements for Interval CoverageDec 07 2014We consider an interval coverage problem. Given $n$ intervals of the same length on a line $L$ and a line segment $B$ on $L$, we want to move the intervals along $L$ such that every point of $B$ is covered by at least one interval and the sum of the moving ... More
Multi-spectral Observations of Lunar Occultations: I. Resolving The Dust Shell Around AFGL 5440Apr 02 2007We present observations and modeling of a lunar occultation of the dust-enshrouded carbon star AFGL 5440. The observations were made over a continuous range of wavelengths from 1 - 4um with a high-speed spectrophotometer designed expressly for this purpose. ... More
Popper's Experiment and Superluminal CommunicationJul 13 2005We comment on Tabesh Qureshi, "Understanding Popper's Experiment," AJP 73, 541 (June 2005), in particular on the implications of its section IV. We show, in the situation envisaged by Popper, that analysis solely with conventional non-relativistic quantum ... More
Density PDFs of diffuse gas in the Milky WayApr 13 2011The probability distribution functions (PDFs) of the average densities of the diffuse ionized gas (DIG) and the diffuse atomic gas are close to lognormal, especially when lines of sight at |b|<5 degree and |b|>5 degree are considered separately. Our results ... More
Efficient simulation of sparse Markovian quantum dynamicsNov 17 2016Quantum algorithms for simulating Hamiltonian dynamics have been extensively developed, but there has been much less work on quantum algorithms for simulating the dynamics of open quantum systems. We give the first efficient quantum algorithms for simulating ... More
Cosmic Rays in a Galactic BreezeJul 29 2016Motivated by the discovery of the non-thermal Fermi bubble features both below and above the Galactic plane, we investigate a scenario in which these bubbles are formed through Galacto-centric outflow. Cosmic rays (CR) both diffusing and advecting within ... More
Cosmic Rays in a Galactic BreezeJul 29 2016Jan 09 2017Motivated by the discovery of the non-thermal Fermi bubble features both below and above the Galactic plane, we investigate a scenario in which these bubbles are formed through Galacto-centric outflow. Cosmic rays (CR) both diffusing and advecting within ... More
Determining Supersymmetric Parameters With Dark Matter ExperimentsJul 07 2006In this article, we explore the ability of direct and indirect dark matter experiments to not only detect neutralino dark matter, but to constrain and measure the parameters of supersymmetry. In particular, we explore the relationship between the phenomenological ... More
Limitations on the Photo-disintegration Process as a Source of VHE PhotonsMay 18 2010Aug 06 2010We consider whether photo-disintegration is ever able to provide an effective mechanism for the production of VHE $\gamma$-ray emission from astrophysical sources. We find that the efficiency of this process is always smaller by a factor $A/Z^{2}$ ($\sim ... More