Results for "George Karypis"

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Distributed representation of multi-sense words: A loss-driven approachApr 14 2019Word2Vec's Skip Gram model is the current state-of-the-art approach for estimating the distributed representation of words. However, it assumes a single vector per word, which is not well-suited for representing words that have multiple senses. This work ... More
Text segmentation on multilabel documents: A distant-supervised approachApr 14 2019Segmenting text into semantically coherent segments is an important task with applications in information retrieval and text summarization. Developing accurate topical segmentation requires the availability of training data with ground truth information ... More
Will this Course Increase or Decrease Your GPA? Towards Grade-aware Course RecommendationApr 22 2019In order to help undergraduate students towards successfully completing their degrees, developing tools that can assist students during the course selection process is a significant task in the education domain. The optimal set of courses for each student ... More
Sparse Neural Attentive Knowledge-based Models for Grade PredictionApr 22 2019Grade prediction for future courses not yet taken by students is important as it can help them and their advisers during the process of course selection as well as for designing personalized degree plans and modifying them based on their performance. ... More
Adaptive Matrix Completion for the Users and the Items in TailApr 22 2019Recommender systems are widely used to recommend the most appealing items to users. These recommendations can be generated by applying collaborative filtering methods. The low-rank matrix completion method is the state-of-the-art collaborative filtering ... More
Causal Inference in Higher Education: Building Better CurriculumsJun 11 2019Higher educational institutions constantly look for ways to meet students' needs and support them through graduation. Recent work in the field of learning analytics have developed methods for grade prediction and course recommendations. Although these ... More
Learning from Sets of Items in Recommender SystemsApr 22 2019Most of the existing recommender systems use the ratings provided by users on individual items. An additional source of preference information is to use the ratings that users provide on sets of items. The advantages of using preferences on sets are two-fold. ... More
Feature-based factorized Bilinear Similarity Model for Cold-Start Top-n Item RecommendationApr 22 2019Recommending new items to existing users has remained a challenging problem due to absence of user's past preferences for these items. The user personalized non-collaborative methods based on item features can be used to address this item cold-start problem. ... More
When being Weak is Brave: Privacy in Recommender SystemsMay 18 2001We explore the conflict between personalization and privacy that arises from the existence of weak ties. A weak tie is an unexpected connection that provides serendipitous recommendations. However, information about weak ties could be used in conjunction ... More
Scalable Label Propagation for Multi-relational Learning on Tensor Product GraphFeb 20 2018Label propagation on the tensor product of multiple graphs can infer multi-relations among the entities across the graphs by learning labels in a tensor. However, the tensor formulation is only empirically scalable up to three graphs due to the exponential ... More
Reduction of couplings in the MSSMJul 16 2015We present an application of the reduction of couplings program in the minimal supersymmetric Standard Model (MSSM). We investigate if a functional relation between $\alpha_1$ and $\alpha_2$ gauge couplings can be realized which is Renormalization Group ... More
Predictable Software -- A Shortcut to Dependable Computing ?Mar 11 2004Many dependability techniques expect certain behaviors from the underlying subsystems and fail in chaotic ways if these expectations are not met. Under expected circumstances, however, software tends to work quite well. This paper suggests that, instead ... More
Parallelized Proximity-Based Query Processing Methods for Road NetworksJul 26 2016In this paper, we propose a paradigm for processing in parallel graph joins in road networks. The methodology we present can be used for distance join processing among the elements of two disjoint sets R,S of nodes from the road network, with R preceding ... More
Anosov C-systems and random number generatorsJul 22 2015Jan 12 2016We are developing further our earlier suggestion to use hyperbolic Anosov C-systems for the Monte-Carlo simulations in high energy particle physics. The hyperbolic dynamical systems have homogeneous instability of all trajectories and as such they have ... More
Extinction Law at a Distance up to 25 kpc toward the Galactic PolesJun 29 2016Photometry from the Tycho-2, 2MASS, and WISE catalogues for clump and branch giants at a distance up to 25 kpc toward the Galactic poles has allowed the variations of various characteristics of the infrared interstellar extinction law with distance to ... More
Dependence of Kinematics on the Age of Stars in the Solar NeighborhoodJun 28 2016The variations of kinematic parameters with age are considered for a sample of 15 402 thin-disk O--F stars with accurate $\alpha$, $\delta$, $\mu$, and $\pi>3$ mas from the Hipparcos catalogue and radial velocities from the PCRV catalogue. The ages have ... More
Strongly Correlated Electron Materials: Dynamical Mean-Field Theory and Electronic StructureMar 03 2004These are introductory lectures to some aspects of the physics of strongly correlated electron systems. I first explain the main reasons for strong correlations in several classes of materials. The basic principles of dynamical mean-field theory (DMFT) ... More
Verifying the Planetary Nebula Luminosity Function MethodAug 20 1996The planetary nebula luminosity function (PNLF) technique for determining distances to galaxies now has been applied to 34 galaxies, including 6 in the Virgo cluster and 3 in the Fornax cluster. Of these, 16 galaxies are late-type or spirals and presumably ... More
Rationality properties of unipotent representationsMar 30 2001We describe those unipotent representations of a finite group of Lie type which are defined over the rational numbers.
Nucleosynthesis from massive stars 50 years after B2FHAug 23 2007We review some important observed properties of massive stars. Then we discuss how mass loss and rotation affect their evolution and help in giving better fits to observational constraints. Consequences for nucleosynthesis at different metallicities are ... More
Physics of rotation in stellar modelsJan 18 2008In these lecture notes, we present the equations presently used in stellar interior models in order to compute the effects of axial rotation. We discuss the hypotheses made. We suggest that the effects of rotation might play a key role at low metallicity. ... More
Density functionals derived from Feynman diagramsOct 10 2009Dec 22 2009We construct a stationary density functional for the partition function from a chosen set of one (boson) line irreducible Feynman diagrams. The construction does not proceed by the inversion of a Legendre transform. It is formulated for fermions with ... More
A Menu-Driven Software Package of Bayesian Nonparametric (and Parametric) Mixed Models for Regression Analysis and Density EstimationJun 17 2015Jul 14 2015Most of applied statistics involves regression analysis of data. This paper presents a stand-alone and menu-driven software package, Bayesian Regression: Nonparametric and Parametric Models. Currently, this package gives the user a choice from 83 Bayesian ... More
Non-Abelian Surprises in GravityJan 21 1997We present a brief review of some recent results on non-abelian solitons and black holes in different theories. Lecture given at the Simi-96, Tbilisi, Georgia, September 22-28, 1996.
Fermions in the Background of Dilatonic SphaleronsOct 24 1994We discuss the properties and interpretation of a discrete sequence of a static spherically symmetric solutions of the Yang-Mills-dilaton theory. This sequence is parametrized by the number $n$ of zeros of a component of the gauge field potential. It ... More
Picard groups of differential operators on curvesOct 21 2010Let X be a complex affine curve (not isomorphic to the affine line), and let Pic(D) be the group of autoequivalences of the category of D(X)-modules. Cannings and Holland have shown that Pic(D) fits into an exact sequence in which the other groups can ... More
The Red Giant Branch in the Tycho-2 CatalogueJul 02 2016Based on multicolor photometry from the 2MASS and Tycho-2 catalogues, we have produced a sample of 38 368 branch red giants that has less than 1\% of admixtures and is complete within 500 pc of the Sun. The sample includes 30 671 K giants, 7544 M giants, ... More
Multi-Tape Two-Level Morphology: A Case Study in Semitic Non-linear MorphologyJul 26 1994This paper presents an implemented multi-tape two-level model capable of describing Semitic non-linear morphology. The computational framework behind the current work is motivated by Kay (1987); the formalism presented here is an extension to the formalism ... More
Can Ballistic Electrons Probe the Electronic Spectra of Individual Buried Molecules?Nov 21 2006A theoretical study is presented of the ballistic electron emission spectra (BEES) of individual insulating and conducting organic molecules chemisorbed on a silicon substrate and buried under a thin gold film. It is predicted that ballistic electrons ... More
Composite Fermion Edge States and Transport Through Nanostructures in the Fractional Quantum Hall RegimeMar 02 1996A theory of transport through semiconductor nanostructures in the fractional quantum Hall regime is proposed, based on a model of composite fermion edge states. Adiabatic and non-adiabatic constrictions and constrictions containing artificial impurities ... More
The Nub of an Automorphism of a Totally Disconnected, Locally Compact GroupDec 19 2011To any automorphism, $\alpha$, of a totally disconnected, locally compact group, $G$, there is associated a compact, $\alpha$-stable subgroup of $G$, here called the \emph{nub} of $\alpha$, on which the action of $\alpha$ is topologically transitive. ... More
Superfluid Transition in a Chiron GasDec 19 2007Low temperature measurements of the magnetic susceptibility of LSCO suggest that the superconducting transition is associated with the disappearance of a vortex liquid. In this note we wish to draw attention to the fact that spin-orbit-like interactions ... More
A Unique Theory of Gravity and MatterFeb 25 1998The author has previously suggested that the ground state for 4-dimensional quantum gravity can be represented as a condensation of non-linear gravitons connected by Dirac strings. In this note we suggest that the low-lying excitations of this state can ... More
Can a closed critical surface in a quark-gluon plasma serve as a model for the behavior of quantum gravity near to an event horizon?Jun 05 2012Time stands still at a quantum critical point in the sense that correlation functions near to the critical point are approximately independent of frequency. In the case of a quantum liquid this would imply that classical hydrodynamics breaks down near ... More
Dark Energy Stars and AdS/CFTJul 25 2009The theory of dark energy stars illustrates how the behavior of matter near to certain kinds of quantum critical phase transitions can be given a geometrical interpretation by regarding the criticality tuning parameter as an extra dimension. In the case ... More
Amplifiers and Suppressors of Selection for the Moran Process on Undirected GraphsNov 05 2016We consider the classic Moran process modeling the spread of genetic mutations, as extended to structured populations by Lieberman et al.\ (Nature, 2005). In this process, individuals are the vertices of a connected graph $G$. Initially, there is a single ... More
Quantized detector network POVMs and the Franson-Bell experimentSep 19 2008We present a generalized POVM formalism for the calculation of quantum optics networks of arbitrary complexity and apply it in a detailed analysis of the Franson-Bell experiment. Our analysis suggests that when it comes to observations of quantum processes, ... More
Quantized Detector Networks: a Quantum Informational Approach to the Description and Interpretation of Quantum PhysicsNov 21 2005We discuss the QDN (quantized detector network) approach to the formulation and interpretation of quantum mechanics. This approach gives us a system-free approach to quantum physics. By this, we mean having a proper emphasis on those aspects of physics ... More
Belyi pairs in the critical filtrations of Hurwitz spacesFeb 06 2019The \it critical filtration \rm of a Hurwitz space stratifies it according to the number of the critical values; the \it Belyi pairs \rm (three critical values) are considered as the 0-dimensional strata of these filtrations. The 1-dimensional strata ... More
Spin CohomologyOct 22 2004We explore differential and algebraic operations on the exterior product of spinor representations and their twists that give rise to cohomology, the spin cohomology. A linear differential operator $d$ is introduced which is associated to a connection ... More
Praaline: Integrating Tools for Speech Corpus ResearchFeb 08 2018This paper presents Praaline, an open-source software system for managing, annotating, analysing and visualising speech corpora. Researchers working with speech corpora are often faced with multiple tools and formats, and they need to work with ever-increasing ... More
Closures of locally divergent orbits of maximal tori and values of homogeneous formsJan 05 2018Let $\G$ be a semisimple algebraic group over a number field $K$, $\mathcal{S}$ a finite set of places of $K$, $K_\mathcal{S}$ the direct product of the completions $K_v, v \in \mathcal{S}$, and $\OO$ the ring of $\mathcal{S}$-integers of $K$. Let $G ... More
An Essay on the Application of mathematical Analysis to the theories of Electricity and MagnetismJul 01 2008Green's famous essay (Nottingham, 1828), with which he introduced the potential function, was transcribed from its reprint in Crelle's Journal (1850-54), with several typographical corrections and a reference section added. Green starts with accounts ... More
Image Parsing with a Wide Range of Classes and Scene-Level ContextOct 24 2015This paper presents a nonparametric scene parsing approach that improves the overall accuracy, as well as the coverage of foreground classes in scene images. We first improve the label likelihood estimates at superpixels by merging likelihood scores from ... More
A Multipoint Method for Approximation of Wavefunctions at a Mesoscopic ScaleDec 05 2014We discuss the concept of a mesoscopic wavefunction, first in a general context, as the concept of wavefunction has evolved, and then in a more specific context of modeling. The paper concentrates on a simple, abstract one-dimensional situation. In this ... More
Conformal Scalar Propagation on the Schwarzschild Black-Hole GeometrySep 26 2009Jan 06 2010The vacuum activity generated by the curvature of the Schwarzschild black-hole geometry close to the event horizon is studied for the case of a massless, conformal scalar field. The associated approximation to the unknown, exact propagator in the Hartle-Hawking ... More
Congruences and trajectories in planar semimodular latticesJun 02 2014Oct 09 2014A 1955 result of J.~Jakub\'i k states that for the prime intervals $\fp$ and $\fq$ of a finite lattice, $\con{\fp} \geq \con{\fq}$ if{}f $\fp$ is congruence-projective to~$\fq$ (\emph{via} intervals of arbitrary size). The problem is how to determine ... More
Mathematical Interpretation of Plato's Third Man ArgumentJun 08 2014The main aim of this article is to defend the thesis that Plato apprehended the structure of incommensurable magnitudes in a way that these magnitudes correspond in a unique and well defined manner to the modern concept of the "Dedekind cut". Thus, the ... More
Special birational structures on non-Kähler complex surfacesAug 08 2015Jan 12 2016We investigate the following conjecture: all compact non-K\"ahler complex surfaces admit birational structures. After Inoue-Kobayashi-Ochiai, the remaining cases to study are essentially surfaces in class VII_0^+. In case of Kato surfaces with a cycle ... More
A technical lemma for congruences of finite latticesAug 21 2013Aug 26 2013The classical Technical Lemma for congruences is not difficult to prove but it is very efficient in its applications. We present here a Technical Lemma for congruences on \emph{finite lattices}. This is not difficult to prove either but it has already ... More
Group Invariant Bounded Linear Functions on Dedekind Complete Totally Ordered Riesz SpacesJan 20 2017In this paper we consider the set of all bounded subsets of totally ordered Dedekind complete Riesz spaces, equipped with the order topology. We show the existence of bounded linear functions on this set, that are invariant under group actions of the ... More
A Dirichlet Process Functional Approach to Heteroscedastic-Consistent Covariance EstimationFeb 16 2016Jun 11 2016The mixture of Dirichlet process (MDP) defines a flexible prior distribution on the space of probability measures. This study shows that ordinary least-squares (OLS) estimator, as a functional of the MDP posterior distribution, has posterior mean given ... More
Torseurs associes a certaines relations algebriques entre polyzetas aux racines de l'uniteDec 04 2000Mar 05 2001We describe in this note a torsor structure arising on the affine scheme defined by a system of rationnal algebraic relations between polyzetas at roots of unity (values of hyperlogarithmic functions on a fixed finite group of complex roots of unity). ... More
Non-Noether symmetries and their influence on phase space geometryNov 09 2002Jul 09 2003We disscuss some geometric aspects of the concept of non-Noether symmetry. It is shown that in regular Hamiltonian systems such a symmetry canonically leads to a Lax pair on the algebra of linear operators on cotangent bundle over the phase space. Correspondence ... More
Deformation of singularities and additive invariantsOct 30 2013Oct 31 2013In this survey on local additive invariants of real and complex definable singular germs we systematically present classical or more recent invariants of different nature as emerging from a tame degeneracy principle. For this goal, we associate to a given ... More
A subsequence characterization of sequences spanning isomorphically polyhedral Banach spacesOct 14 1996Let $(x_n)$ be a sequence in a Banach space $X$ which does not converge in norm, and let $E$ be an isomorphically precisely norming set for $X$ such that \[ \sum_n |x^*(x_{n+1}-x_n)|< \infty, \; \forall x^* \in E. \qquad (*) \] Then there exists a subsequence ... More
Limits Of One Dimensional DiffusionsDec 14 2007Aug 17 2008In this paper we look at the properties of limits of a sequence of real valued time inhomogeneous diffusions. When convergence is only in the sense of finite-dimensional distributions then the limit does not have to be a diffusion. However, we show that ... More
A note on the method of minimal vectorsFeb 01 2002The methods of "minimal vectors" were introduced by Ansari and Enflo and strengthened by Pearcy, in order to prove the existence of hyperinvariant subspaces for certain operators on Hilbert space. In this note we present the method of minimal vectors ... More
On Fermat's equation over some quadratic imaginary number fieldsOct 25 2017Apr 24 2018Assuming a deep but standard conjecture in the Langlands programme, we prove Fermat's Last Theorem over $\mathbb Q(i)$. Under the same assumption, we also prove that, for all prime exponents $p \geq 5$, Fermat's equation $a^p+b^p+c^p=0$ does not have ... More
The Massive Klein-Gordon Field Coupled to a Harmonic Oscillator at the BoundaryDec 07 2004Sep 26 2005We consider the massive Klein-Gordon field on the half line with and without a Robin boundary potential.The field is coupled at the boundary to a harmonic oscillator.We solve the system classically and observe the existence of classical boundary bound ... More
The maximal operators of logarithmic means of one-dimensional Vilenkin-Fourier seriesOct 05 2014The main aim of this paper is to investigate (H_{p},L_{p})-type inequalities for maximal operators of logarithmic means of one-dimensional Vilenkin-Fourier series.
Strong convergence of two-dimensional Walsh-Fourier seriesOct 05 2014We prove that certain mean of the quadratical partial sums of the two-dimensional Walsh-Fourier series are uniformly bounded operators from the Hardy space $H_{p}$ to the space $L_{p}$ for $0<p<1.$
On the Partial Sums and Marcinkiewicz and Fejér Means on the One- and Two-dimensional One-parameter Martingale Hardy SpacesFeb 09 2019In this PhD thesis we are dealing with convergence and summability of partial sums, Fej\'er and Marcinkiewicz means with respect to one- and two-dimensional Walsh-Fourier series on the martingale Hardy spaces. This thesis is focus to achieve the following ... More
On Two Theorems About Symplectic Reflection AlgebrasDec 22 2006Feb 02 2007We give a new proof and an improvement of two Theorems of J. Alev, M.A. Farinati, T. Lambre and A.L. Solotar : the first one about Hochschild cohomology spaces of some twisted bimodules of the Weyl algebra W and the second one about Hochschild cohomology ... More
Homotopical exact squares and derivatorsJan 21 2011The aim of this paper is to generalize in a homotopical framework the notion of exact square introduced by Ren\'e Guitart, and explain the relationship between this generalization and the theory of derivators.
A cornucopia of quasi-Yamanouchi tableauxJul 27 2018Quasi-Yamanouchi tableaux are a subset of semistandard Young tableaux and refine standard Young tableaux. They are closely tied to the descent set of standard Young tableaux and were introduced by Assaf and Searles to tighten Gessel's fundamental quasisymmetric ... More
Matching of analytical and numerical solutions for neutron stars of arbitrary rotationJan 29 2012We demonstrate the results of an attempt to match the two-soliton analytical solution with the numerically produced solutions of the Einstein field equations, that describe the spacetime exterior of rotating neutron stars, for arbitrary rotation. The ... More
The April First PhenomenonMar 28 2014A true quantum reason for why people fib on April first.
A toy quantum analog of enzymesOct 19 2015We present a quantum system incorporating qualitative aspects of enzyme action in which the possibility of quantum superposition of several conformations of the enzyme-substrate complex is investigated. We present numerical results showing quantum effects ... More
Comparison of the Pulkovo Compilation of Radial Velocities with the RAVE DR1 CatalogueJun 25 2016The Data Release 1 of the Radial-Velocity Experiment (RAVE DR1, 24 748 stars) is compared with the May 15, 2006 version of the Pulkovo Compilation of Radial Velocities (PCRV, 35 495 stars). RAVE DR1 includes mostly $9^m-13^m$ stars, while the PCRV contains ... More
Localizing subcategories in the bootstrap category of filtered C*-algebrasFeb 01 2016We use the abelian approximation for the bootstrap category of filtered C*-algebras to define a sensible notion of support for its objects. As a consequence, we provide a full classification of localizing subcategories in terms of a product of lattices ... More
H0 RevisitedNov 14 2013Feb 08 2014I reanalyse the Riess et al. (2011, hereafter R11) Cepheid data using the revised geometric maser distance to NGC 4258 of Humphreys et al. (2013). I explore different outlier rejection criteria designed to give a reduced chi-squared of unity and compare ... More
Normal Galaxies in the InfraredMay 09 2000This review addresses what can be learned from infrared observations about galaxies powered predominantly by star formation. Infrared techniques mostly probe the interstellar medium of galaxies, yielding physical and chemical information on the medium ... More
A note on the norm convergence by Vilenkin-Fejér meansFeb 14 2015The main aim of this paper is to find necessary and sufficient conditions for the convergence of Fej\'er means in terms of the modulus of continuity on the Hardy spaces $H_{p},$ when $0<p\leq 1/2.$
Survival exponents for some Gaussian processesMar 12 2012The problem is a power-law asymptotics of the probability that a self-similar process does not exceed a fixed level during long time. The exponent in such asymptotics is estimated for some Gaussian processes, including the fractional Brownian motion (FBM) ... More
On the homotopy type of certain cobordism categories of surfacesAug 30 2010Mar 14 2011Let $\mathcal{A}_{g,d}$ be the (topological) cobordism category of orientable surfaces whose connected components are homeomorphic to either $S^1 \times I$ with one incoming and one outgoing boundary component or the surface $\Sigma_{g,d}$ of genus $g$ ... More
Projective Connections and Schwarzian Derivatives for Supermanifolds, and Batalin-Vilkovisky OperatorsSep 29 2009We extend the notion of a Thomas projective connection (a projective equivalence class of linear connections) for supermanifolds. As a by-product, we arrive at a generalisation of the multidimensional Schwarzian derivative for the super case which was ... More
A Canonical Laplacian on the Algebra of Densities on a Projectively Connected ManifoldSep 29 2009On a manifold with a projective connection we canonically assign a second order differential operator acting on the algebra of all densities to any tensor density $S^{ij}$ of fixed weight $\lambda$. In particular, this implies that on any projectively ... More
Some Early Ideas on the Metric Geometry of ThermodynamicsApr 09 2016It is a pleasure to write for this 90'th anniversary volume of Journal of Low Temperature Physics dedicated to Horst Meyer at Duke University. I was a PhD student with Horst in the period 1975-1980, working in experimental low temperature physics. While ... More
Notes on the vector adelic GrassmannianJun 23 2015These are notes about the connection between the Gibbons-Hermsen system and the multi-component KP hierarchy: they were intended as a first sketch of a paper on that subject, but since it seems unlikely that I will ever write such a paper I have decided ... More
On the quadratic action of the Hawking-Turok instantonApr 22 1998May 01 1998Positive definiteness of the quadratic part of the action of the Hawking-Turok instanton is investigated. The Euclidean quadratic action for scalar perturbations is expressed in terms of a single gauge invariant quantity $q$. The mode functions satisfy ... More
On instability of Rubakov-Shaposhnikov modelFeb 24 2010Instability of 6 dimensional Rubakov-Shaposhnikov model is reinvestigated. It is shown that the model is unstable in scalar perturbations sector with very particular instability pattern: there are no unstable modes for the first two lowest angular harmonics, ... More
Gravitating, Gravitational and Dilatonic SphaleronsAug 05 1995This is a brief review of the main properties of sphalerons in various theories with a Yang--Mills field. Talk given at the Heat Kernel Techniques and Quantum Gravity, Winnipeg, Canada, August 2-6, 1994.
Magnetic spin excitations in diluted ferromagnetic systems: the case of $Ga_{1-x}Mn_{x}As$Oct 17 2006Jul 11 2007We propose a theory which allow to calculate the magnetic excitation spectrum in diluted ferromagnetic systems. The approach is rather general and based on the Self-Consistent local Random Phase Approximation in which disorder (dilution) and thermal fluctuations ... More
Solution of the Gross-Pitaevskii equation in terms of the associated non-linear Hartree potentialJul 15 2013The Gross-Pitaevskii equation (GP), that describes the wave function of a number of coherent Bose particles contained in a trap, contains the cube of the normalized wave function, times a factor proportional to the number of coherent atoms. The square ... More
Iterative solution of integral equations on a basis of positive energy Sturmian eigenfunctionsFeb 10 2011Years ago S. Weinberg suggested the "Quasi-Particle" method (Q-P) for iteratively solving an integral equation, based on an expansion in terms of sturmian functions that are eigenfunctions of the integral kernel. An improvement of this method is presented ... More
Rashba-Dirac cones at the tungsten surface: Insights from a tight-binding model and thin film subband structureNov 11 2016A tight-binding model of bcc tungsten that includes spin-orbit coupling is developed and applied to the surface states of (110) tungsten thin films. The model describes accurately the anisotropic Dirac cone-like dispersion and Rashba-like spin polarization ... More
On the appearance of compact objects at radio and optical frequenciesJun 25 2009In the dark energy star picture a compact object is transparent at radio and optical frequencies, and acts as a defocusing lens. Thus the object itself appears as a luminous disk whose surface brightness reflects the surface brightness of the background. ... More
Blueprint for a rotating UniversAug 17 2006Aug 24 2006A solution of the vacuum Einstein equations with a cosmological constant is exhibited which can perhaps be used to describe the interior of compact rotating objects, and may also provide a description of our universe on length scales approaching the size ... More
Quantum Criticality and the Alpha/Delta PuzzleOct 11 2008In this paper we suggest a novel explanation for the alpha-delta transition in plutonium based on an analogy between the evolution of the actinide ground state as a function of spin orbit coupling and the behaviour of thin film superconductors in a magnetic ... More
Time-dependent diffusion in A-starsMay 05 1998Each time diffusion of elements is invoked in explaining abundance anomalies in a star, this supposes implicitly that a stratification process is in progress somewhere in that star. This means also, that the element abundances can still be evolving according ... More
On transfer maps in the algebraic $K$-theory of spacesJan 16 2019We show that the Waldhausen trace map $\mathrm{Tr}_X \colon A(X) \to QX_+$, which defines a natural splitting map from the algebraic $K$-theory of spaces to stable homotopy, is natural up to \emph{weak} homotopy with respect to transfer maps in algebraic ... More
Thinking locally: reflections on Dynamical Mean-Field Theory from a high-temperature/high energy perspectiveDec 22 2011When spatial correlations are short-range, the physics of strongly correlated systems is controlled by local quantum fluctuations. In those regimes, Dynamical Mean-Field Theory can be viewed as a `compass' which provides guidance on the relevant degrees ... More
Quantized Detector Networks: A review of recent developmentsSep 26 2007QDN (quantized detector networks) is a description of quantum processes in which the principal focus is on observers and their apparatus, rather than on states of SUOs (systems under observation). It is a realization of Heisenberg's original instrumentalist ... More
The running of the Universe and the quantum structure of timeMay 04 2001May 14 2001Some principles underpinning the running of the Universe are discussed. The most important, the machine principle, states that the Universe is a fully autonomous, self-organizing and self-testing quantum automaton. Continuous space and time, consciousness ... More
Discrete spacetime: classical causality,prediction, retrodiction and the mathematical arrow of timeApr 08 2000A mathematical definition of classical causality over discrete spacetime dynamics is formulated. The approach is background free and permits a definition of causality in a precise way whenever the spacetime dynamics permits. It gives a natural meaning ... More
The Emergence of Norms via Contextual Agreements in Open SocietiesMar 24 2015This paper explores the emergence of norms in agents' societies when agents play multiple -even incompatible- roles in their social contexts simultaneously, and have limited interaction ranges. Specifically, this article proposes two reinforcement learning ... More
From non-Kählerian surfaces to Cremona group of P^2(C)Jun 12 2012Sep 14 2013For any minimal compact complex surface S with n=b_2(S)>0 containing global spherical shells (GSS) we study the effectiveness of the 2n parameters given by the n blown up points. There exists a family of surfaces with GSS which contains as fibers S, some ... More
Consistency Strengths of Modified Maximality PrinciplesJun 03 2004The Maximality Principle MP is a scheme which states that if a sentence of the language of ZFC is true in some forcing extension V^P, and remains true in any further forcing extension of V^P, then it is true in all forcing extensions of V. A modified ... More
A Hennings TQFT Construction for Quasi-Hopf AlgebrasNov 22 2013We extend the construction of the Hennings TQFT for ribbon Hopf algebras to the case of ribbon quasi-Hopf algebras as defined by Drinfeld. Calculations proceed in a similar fashion to the ordinary Hopf algebra case, but also require the handling of the ... More