Results for "Radoslaw Martin Cichy"

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The Algonauts Project: A Platform for Communication between the Sciences of Biological and Artificial IntelligenceMay 14 2019In the last decade, artificial intelligence (AI) models inspired by the brain have made unprecedented progress in performing real-world perceptual tasks like object classification and speech recognition. Recently, researchers of natural intelligence have ... More
Can visual information encoded in cortical columns be decoded from magnetoencephalography data in humans?Mar 27 2015It is a principal open question whether noninvasive imaging methods in humans can decode information encoded at a spatial scale as fine as the basic functional unit of cortex: cortical columns. We addressed this question in five magnetoencephalography ... More
Metallicity dependence of the Blazhko effectMar 29 2005The microlensing surveys, such as OGLE or MACHO, have led to the discovery of thousands of RR Lyrae stars in the Galactic Bulge and in the Magellanic Clouds, allowing for detailed investigation of these stars, specially the still mysterious Blazhko phenomenon. ... More
Mixture of anisotropic fluidsSep 11 2013The recently introduced approach describing coupled quark and gluon anisotropic fluids is generalized to include explicitly the transitions between quarks and gluons. We study the effects of such processes on the thermalization rate of anisotropic systems. ... More
Carbon dioxide emission during forest fires ignited by lightningMar 31 2009In this paper we developed the model for the carbon dioxide emission from forest fire. The master equation for the spreading of the carbon dioxide to atmosphere is the hyperbolic diffusion equation. In the paper we study forest fire ignited by lightning. ... More
Admissibility of diagonal state-delayed systems with a one-dimensional input spaceMay 12 2018Mar 17 2019In this paper we investigate admissibility of the control operator $B$ in a Hilbert space state-delayed dynamical system setting of the form $\dot{z}(t)=Az(t-\tau)+Bu(t)$, where $A$ generates a diagonal semigroup and $u$ is a scalar input function. Our ... More
Vortex-like solutions and internal structures of covariant ideal magnetohydrodynamicsMar 18 2018We discuss a manifestly covariant formulation of ideal relativistic magnetohydrodynamics, which has been recently used in astrophysical and heavy-ion contexts, and compare it to other similar frameworks. We show that the covariant equations allow for ... More
Thermodynamic versus kinetic approach to polarization-vorticity couplingJun 07 2018Aug 23 2018We critically compare thermodynamic and kinetic approaches, that have been recently used to study relations between the spin polarization and fluid vorticity in systems consisting of spin-one-half particles. The thermodynamic approach refers to general ... More
Anisotropic-hydrodynamics approach to a quark-gluon fluid mixtureNov 09 2017Anisotropic-hydrodynamics framework is used to describe a mixture of quark and gluon fluids. The effects of quantum statistics, finite quark mass, and finite baryon number density are taken into account. The results of anisotropic hydrodynamics are compared ... More
Testing viscous and anisotropic hydrodynamics in an exactly solvable caseMay 30 2013Aug 07 2013We exactly solve the one-dimensional boost-invariant Boltzmann equation in the relaxation time approximation for arbitrary shear viscosity. The results are compared with the predictions of viscous and anisotropic hydrodynamics. Studying different non-equilibrium ... More
How to measure diffusional decoherence in multimode rubidium vapor memories?Apr 19 2013May 17 2014Diffusion is the main limitation of storage time in spatially multimode applications of warm atomic vapors. Precise knowledge of diffusional decoherence in the system is desired for designing most of vapor memory setups. Here we present a novel, efficient ... More
Deep Neural Networks predict Hierarchical Spatio-temporal Cortical Dynamics of Human Visual Object RecognitionJan 12 2016The complex multi-stage architecture of cortical visual pathways provides the neural basis for efficient visual object recognition in humans. However, the stage-wise computations therein remain poorly understood. Here, we compared temporal (magnetoencephalography) ... More
Recurrence required to capture the dynamic computations of the human ventral visual streamMar 14 2019The visual system is an intricate network of brain regions that enables us to recognize the world around us. Despite its abundant lateral and feedback connections, human object processing is commonly viewed and studied as a feedforward process. Here, ... More
Mass spectra of mesons containing charm quarks - continuum limit results from twisted mass fermionsOct 27 2015We present results from an ongoing computation of masses of $D$ mesons, $D_s$ mesons and charmonium, including both ground states and several parity and angular momentum excitations. We employ 2+1+1 flavours of dynamical maximally twisted mass fermions ... More
The continuum limit of the $D$ meson, $D_s$ meson and charmonium spectrum from $N_f=2+1+1$ twisted mass lattice QCDMar 21 2016We compute masses of $D$ meson, $D_s$ meson and charmonium states using $N_f=2+1+1$ Wilson twisted mass lattice QCD. All results are extrapolated to physical light quark masses, physical strange and charm quark masses and to the continuum. Our analysis ... More
Continuum limit of the $D$ meson, $D_s$ meson and charmonium spectrum from $N_f=2+1+1$ twisted mass lattice QCDMar 21 2016Nov 22 2016We compute masses of $D$ meson, $D_s$ meson and charmonium states using $N_f=2+1+1$ Wilson twisted mass lattice QCD. All results are extrapolated to physical light quark masses, physical strange and charm quark masses and to the continuum. Our analysis ... More
Strong-coupling effects in a plasma of confining gluonsDec 20 2015The plasma consisting of confining gluons resulting from the Gribov quantization of the SU(3) Yang-Mills theory is studied using non-equilibrium fluid dynamical framework. Exploiting the Bjorken symmetry and using linear response theory a general analytic ... More
Relativistic quantum transport coefficients for second-order viscous hydrodynamicsMar 11 2015May 19 2015We express the transport coefficients appearing in the second-order evolution equations for bulk viscous pressure and shear stress tensor using Bose-Einstein, Boltzmann, and Fermi-Dirac statistics for the equilibrium distribution function and Grad's 14-moment ... More
Technologies for promoting social participation in later lifeJan 14 2019Social participation is known to bring great benefits to the health and well-being of people as they age. From being in contact with others to engaging in group activities, keeping socially active can help slow down the effects of age-related declines, ... More
Masses and Distances of Planetary Microlens Systems with High Angular Resolution ImagingMar 19 2019Microlensing is the only method that can detect and measure mass of wide orbit, low mass, solar system analog exoplanets. Mass measurements of such planets would yield massive science on planet formation, exoplanet demographics, free floating planets, ... More
A crosstalk and non-uniformity correction method for the Compact Space-borne Compton Polarimeter POLARJul 16 2015Jun 30 2016In spite of extensive observations and numerous theoretical studies in the past decades several key questions related with Gamma-Ray Bursts (GRB) emission mechanisms are still to be answered. Precise detection of the GRB polarization carried out by dedicated ... More
Quark mass anomalous dimension and $Λ_{\overline{\textrm{MS}}}$ from the twisted mass Dirac operator spectrumNov 14 2013Jul 29 2014We investigate whether it is possible to extract the quark mass anomalous dimension and its scale dependence from the spectrum of the twisted mass Dirac operator in Lattice QCD. The answer to this question appears to be positive, provided that one goes ... More
A Southern Sky and Galactic Plane Survey for Bright Kuiper Belt ObjectsJul 26 2011About 2500 square degrees of sky south of declination -25 degrees and/or near the galactic plane were surveyed for bright outer solar system objects. This survey is one of the first large scale southern sky and galactic plane surveys to detect dwarf planets ... More
Logarithmic Sobolev Inequalities and Concentration of Measure for Convex Functions and Polynomial ChaosesMay 10 2005Jul 26 2005We prove logarithmic Sobolev inequalities and concentration results for convex functions and a class of product random vectors. The results are used to derive tail and moment inequalities for chaos variables (in spirit of Talagrand and Arcones, Gine). ... More
Some differentiation formulas for Legendre polynomialsOct 25 2009In a series of recent works, we have provided a number of explicit expressions for the derivative of the associated Legendre function of the first kind with respect to its degree, $[\partial P_{\nu}^{m}(z)/\partial\nu]_{\nu=n}$, with $m,n\in\mathbb{N}$. ... More
A note on parameter derivatives of classical orthogonal polynomialsJan 17 2009Nov 16 2010Coefficients in the expansions of the form $\partial P_{n}(\lambda;z)}/\partial\lambda=\sum_{k=0}^{n}a_{nk}(\lambda)P_{k}(\lambda;z)$, where $P_{n}(\lambda;z)$ is the $n$th classical (the generalized Laguerre, Gegenbauer or Jacobi) orthogonal polynomial ... More
Lattice Hamiltonian approach to the massless Schwinger model: precise extraction of the mass gapNov 27 2012Feb 12 2013We present results of applying the Hamiltonian approach to the massless Schwinger model. A finite basis is constructed using the strong coupling expansion to a very high order. Using exact diagonalization, the continuum limit can be reliably approached. ... More
Complexity Considerations, cSAT Lower BoundApr 04 2007Jun 09 2007This article discusses completeness of Boolean Algebra as First Order Theory in Goedel's meaning. If Theory is complete then any possible transformation is equivalent to some transformation using axioms, predicates etc. defined for this theory. If formula ... More
Collective phenomena in the early stages of relativistic heavy-ion collisionsJul 03 2012A recently developed framework of highly-anisotropic and strongly-dissipative hydrodynamics -- ADHYDRO -- has been introduced and used to analyze the space-time evolution of matter produced in ultra-relativistic heavy-ion collisions. The main goal of ... More
On the derivative of the associated Legendre function of the first kind of integer order with respect to its degreeJul 18 2009In our recent works [R. Szmytkowski, J. Phys. A 39 (2006) 15147; corrigendum: 40 (2007) 7819; addendum: 40 (2007) 14887], we have investigated the derivative of the Legendre function of the first kind, $P_{\nu}(z)$, with respect to its degree $\nu$. In ... More
Phase-space shapes of clusters and rich groups of galaxiesOct 14 2013Jan 29 2014Clusters and groups of galaxies are highly aspherical, with shapes approximated by nearly prolate ellipsoids of revolution. An equally fundamental property is the shape of these objects in velocity space which is the anisotropy of the global velocity ... More
Highly-anisotropic hydrodynamics for central collisionsMar 18 2016The framework of leading-order anisotropic hydrodynamics is supplemented with realistic equation of state and self-consistent freeze-out prescription. The model is applied to central proton-nucleus collisions. The results are compared to those obtained ... More
On the derivative of the associated Legendre function of the first kind of integer degree with respect to its orderMar 27 2008The derivative of the associated Legendre function of the first kind of integer degree with respect to its order, $\partial P_{n}^{\mu}(z)/\partial\mu$, is studied. After deriving and investigating general formulas for $\mu$ arbitrary complex, a detailed ... More
Exact controllability of non-Lipschitz semilinear systemsSep 24 2017Mar 30 2018We present sufficient conditions for exact controllability of a semilinear infinite dimensional dynamical system. The system mild solution is formed by a noncompact semigroup and a nonlinear disturbance that does not need to be Lipschitz continuous. Our ... More
On parameter derivatives of the associated Legendre function of the first kind (with applications to the construction of the associated Legendre function of the second kind of integer degree and order)Oct 23 2009A relationship between partial derivatives of the associated Legendre function of the first kind with respect to its degree, $[\partial P_{\nu}^{m}(z)/\partial\nu]_{\nu=n}$, and to its order, $[\partial P_{n}^{\mu}(z)/\partial\mu]_{\mu=m}$, is established ... More
Lattice Hamiltonian approach to the Schwinger model: further results from the strong coupling expansionOct 28 2014Oct 29 2014We employ exact diagonalization with strong coupling expansion to the massless and massive Schwinger model. New results are presented for the ground state energy and scalar mass gap in the massless model, which improve the precision to nearly $10^{-9} ... More
Application of Contractor Renormalization Group (CORE) to the Heisenberg zig-zag and the Hubbard chainMay 14 2008The COntractor REnormalization group method was devised in 1994 by Morningstar and Weinstein. It was primarily aimed at extracting the physics of lattice quantum field theories (like lattice Quantum Chromodynamics). However, it is a general method of ... More
The influence of magnetic field on the superconducting properties and the BCS-BEC crossover in systems with local fermion pairingSep 25 2013The aim of this Ph.D. thesis was to investigate superconducting properties in the presence of Zeeman magnetic field in systems with local fermion pairing on the lattice. The study also concerned the evolution from the weak coupling (BCS-like) limit to ... More
Reentrant Fulde-Ferrell-Larkin-Ovchinnikov superfluidity in the honeycomb latticeOct 17 2017May 29 2018We study superconducting properties of population-imbalanced ultracold Fermi mixtures in the honeycomb lattice that can be effectively described by the spin-imbalanced attractive Hubbard model in the presence of a Zeeman magnetic field. We use the mean-field ... More
Wilson chiral perturbation theory for dynamical twisted mass fermions vs lattice data - a case studyDec 05 2016Nov 28 2018We compute the low lying eigenvalues of the Hermitian Dirac operator in lattice QCD with $N_{\rm f} = 2+1+1$ twisted mass fermions. We discuss whether these eigenvalues are in the $\epsilon$-regime or the $p$-regime of Wilson chiral perturbation theory ... More
On the Imbalanced d-wave Superfluids within the Spin Polarized Extended Hubbard Model: Weak Coupling LimitSep 25 2013We investigate the superfluid properties of d-wave pairing symmetry within the Extended Hubbard Model (EHM) in a magnetic field. We analyze the temperature and magnetic field dependencies of the order parameter. We find that in the two-dimensional case, ... More
On the BCS-BEC crossover in the Spin-Polarized Attractive Hubbard Model at T=0Sep 25 2013The influence of the Zeeman magnetic field ($h$) on the ground state evolution of superfluid properties from the weak coupling (BCS like) to the strong coupling limit of tightly bound local pairs (LP) with increasing attraction has been studied. The analysis ... More
On a generalization of Matérn hard-core processes with applications to max-stable processesSep 18 2017The Mat\'ern hard-core processes are classical examples for point process models obtained from (marked) Poisson point processes. Points of the original Poisson process are deleted according to a dependent thinning rule, resulting in a process whose points ... More
A tight bound on the speed-up through storage for quickest multi-commodity flowsJun 18 2014Multi-commodity flows over time exhibit the non-intuitive property that letting flow wait can allow us to send flow faster overall. Fleischer and Skutella (IPCO~2002) show that the speed-up through storage is at most a factor of~$2$, and that there are ... More
On the representation of polyhedra by polynomial inequalitiesMar 26 2002Oct 24 2002A beautiful result of Br\"ocker and Scheiderer on the stability index of basic closed semi-algebraic sets implies, as a very special case, that every $d$-dimensional polyhedron admits a representation as the set of solutions of at most $d(d+1)/2$ polynomial ... More
Algorithmic Optimisations for Iterative Deconvolution MethodsApr 26 2013We investigate possibilities to speed up iterative algorithms for non-blind image deconvolution. We focus on algorithms in which convolution with the point-spread function to be deconvolved is used in each iteration, and aim at accelerating these convolution ... More
Open-closed modular operads, Cardy condition and string field theoryNov 26 2016We prove that the modular operad of diffeomorphism classes of Riemann surfaces with both `open' and `closed' boundary components, in the sense of string field theory, is the modular completion of its genus 0 part quotiented by the Cardy condition. We ... More
Neutralino Dark Matter and the CurvatonNov 30 2006Mar 09 2007We build a realistic model of curvaton cosmology, in which the energy content is described by radiation, WIMP dark matter and a curvaton component. We calculate the curvature and isocurvature perturbations, allowing for arbitrary initial density perturbations ... More
A guide to light-cone PDFs from Lattice QCD: an overview of approaches, techniques and resultsNov 18 2018Within the theory of Quantum Chromodynamics (QCD), the rich structure of hadrons can be quantitatively characterized, among others, using a basis of universal non-perturbative functions: parton distribution functions (PDFs), generalized parton distributions ... More
I^K-convergenceSep 13 2011In this paper we introduce I^K-convergence which is a common generalization of the I^K-convergence of sequences, double sequences and nets. We show that many results that were shown before for these special cases are true for the I^K-convergence, too
Modern Regularization Methods for Inverse ProblemsJan 30 2018Regularization methods are a key tool in the solution of inverse problems. They are used to introduce prior knowledge and make the approximation of ill-posed (pseudo-)inverses feasible. In the last two decades interest has shifted from linear towards ... More
Orbital magnetism of ultracold fermionic gases in a lattice: dynamical mean-field approachFeb 25 2016May 29 2016We study finite-temperature properties of ultracold four-component mixtures of alkaline-earth-like atoms in optical lattices that can be effectively described by the two-band spin-$1/2$ Hubbard model including the Hund's exchange coupling term. Our main ... More
On the BCS-BEC crossover in the 2D Asymmetric Attractive Hubbard ModelSep 25 2013We analyze the evolution from the weak coupling (BCS-like limit) to the strong coupling limit of tightly bound local pairs (LP's) in the 2D asymmetric attractive Hubbard model, in the presence of the Zeeman magnetic field ($h$). The broken symmetry Hartree ... More
A New Riemannian Setting for Surface RegistrationJun 03 2011Sep 19 2014We present a new approach for matching regular surfaces in a Riemannian setting. We use a Sobolev type metric on deformation vector fields which form the tangent bundle to the space of surfaces. In this article we compare our approach with the diffeomorphic ... More
Spitzer Microlensing parallax reveals two isolated stars in the Galactic bulgeApr 25 2019We report the mass and distance measurements of two single-lens events from the 2017 Spitzer microlensing campaign. The ground-based observations yield the detection of finite-source effects, and the microlens parallaxes are derived from the joint analysis ... More
Multifractal analysis of three-dimensional grayscale images: Characterization of natural porous structuresMay 16 2016A multifractal analysis (MFA) is performed on three-dimensional grayscale images associated with natural porous structures (soil samples). First, computed tomography (CT) scans are carried out on the samples to generate 3D grayscale images. Then, a preliminary ... More
Highly-anisotropic and strongly-dissipative hydrodynamics with transverse expansionMar 07 2011A recently formulated framework of highly-anisotropic and strongly-dissipative hydrodynamics (ADHYDRO) is used to describe the evolution of matter created in ultra-relativistic heavy-ion collisions. New developments of the model contain: the inclusion ... More
Period Change of Eclipsing Binaries from the ASAS CatalogJul 10 2006We present a preliminary statistical analysis of a period change of eclipsing binaries from the ASAS Catalog of Variable Stars. For each contact and semidetached system brighter than 13.3$mag$ (in V) with a period shorter than 0.4 days and at least 300 ... More
Dilepton production from the quark-gluon plasma using (3+1)-dimensional anisotropic dissipative hydrodynamicsJan 14 2015We compute dilepton production from the deconfined phase of the quark-gluon plasma using leading-order (3+1)-dimensional anisotropic hydrodynamics. The anisotropic hydrodynamics equa- tions employed describe the full spatiotemporal evolution of the transverse ... More
Separation of elastic and inelastic processes in the relaxation time approximation for collision integralMar 05 2016We introduce a generalised relaxation-time-approximation form of the collision term in the Boltzmann kinetic equation that allows for using different relaxation times for elastic and inelastic collisions. The efficacy of the proposed framework is demonstrated ... More
Generation and delayed retrieval of spatially multimode Raman scattering in warm rubidium vaporsMay 17 2014We apply collective Raman scattering to create, store and retrieve spatially multimode light in warm rubidium-87 vapors. The light is created in a spontaneous Stokes scattering process. This is accompanied by the creation of counterpart collective excitations ... More
Highly-anisotropic hydrodynamics in 3+1 space-time dimensionsApr 12 2012Recently formulated model of highly-anisotropic and strongly dissipative hydrodynamics is used in 3+1 dimensions to study behavior of matter produced in ultra-relativistic heavy-ion collisions. We search for possible effects of the initial high anisotropy ... More
Twisted supergravity and untwisted super-bigravityMar 26 2003Oct 20 2003We have extended previous analysis of the bulk/brane supersymmetrizations involving non-zero brane mass terms of bulk fermions (gravitini) and twisting of boundary conditions. We have constructed new brane/bulk models that may be relevant for realistic ... More
On Scherk-Schwarz mechanism in gauged five-dimensional supergravity and on its relation to bigravityOct 06 2002Nov 29 2002We demonstrate the relation between the Scherk-Schwarz mechanism and flipped gauged brane-bulk supergravities in five dimensions. We discuss the form of supersymmetry violating Scherk-Schwarz terms in pure supergravity and in supergravity coupled to matter. ... More
Coulomb Effects in FemtoscopyFeb 28 2009Sep 28 2009The correlation function of two identical particles - pions or kaons - interacting via Coulomb potential is computed. The particles are emitted from an anisotropic particle's source of finite lifetime. In the case of pions, the effect of halo is taken ... More
Of Hags and bitches. Ageist attitudes in 2016 presidential debate on twitterNov 11 2016In this article we present our exploratory research into the occurrence of ageist attitudes within the discussion related to the US 2016 presidential election. We use natural processing techniques to analyze the content tweets related to Hillary Clinton ... More
Modeling microlensing events with MulensModelMar 02 2018Jan 07 2019We introduce MulensModel, a software package for gravitational microlensing modeling. The package provides a framework for calculating microlensing model magnification curves and goodness-of-fit statistics for microlensing events with single and binary ... More
$N_f = 2+1+1$ flavours of twisted mass quarks: cut-off effects at tree-level of perturbation theoryDec 22 2010Jan 30 2011We present a calculation of cut-off effects at tree-level of perturbation theory for the K and D mesons using the twisted mass formulation of lattice QCD. The analytical calculations are performed in the time-momentum frame. The relative sizes of cut-off ... More
Stability of superfluid phases in the 2D Spin-Polarized Attractive Hubbard ModelSep 25 2013We study the evolution from the weak coupling (BCS-like limit) to the strong coupling limit of tightly bound local pairs (LP's) with increasing attraction, in the presence of the Zeeman magnetic field ($h$) for $d=2$, within the spin-polarized attractive ... More
Multimode Spontaneous Parametric Down-Conversion in the Lossy MediumOct 26 2009We study the process of multimode Spontaneous Parametric Down--Conversion (SPDC) in the lossy, one dimensional waveguide. We propose a description using first order Correlation Functions (CF) in the fluorescence fields, as a very fruitful and easy approach ... More
Projection method for boost-invariant and cylindrically symmetric dissipative hydrodynamicsNov 25 2011Tensors describing boost-invariant and cylindrically symmetric expansion of a relativistic dissipative fluid are decomposed in a suitable chosen basis of projection operators. This leads to a simple set of scalar equations which determine the fluid behavior. ... More
Highly-anisotropic and strongly-dissipative hydrodynamics for early stages of relativistic heavy-ion collisionsJul 01 2010We introduce a new framework of highly-anisotropic hydrodynamics that includes dissipation effects. Dissipation is defined by the form of the entropy source that depends on the pressure anisotropy and vanishes for the isotropic fluid. With a simple ansatz ... More
Amplitude Saturation in Beta Cephei Models - Preliminary ResultsDec 18 2006Using nonlinear hydrocodes we have calculated single mode saturation amplitudes for beta Cephei models. Predicted saturation amplitudes are systematically higher than amplitudes observed in beta Cephei variables, even in monoperiodic ones. We argue that ... More
Singular gauge transformations and supersymmetry breakdown on warped orbifoldsOct 29 2003Feb 24 2004We have analyzed the breakdown of global supersymmetry by a non-vanishing expectation value of the fifth component of the graviphoton on warped S^1/Z_2 orbifolds. It has been demonstrated that the setups where such a breakdown is possible correspond to ... More
Inaccurate use of asymptotic formulasJan 13 2004Feb 03 2004The asymptotic form of the plane wave decomposition into spherical waves, which is used to express the scattering amplitude in terms of phase shifts, is incorrect. We explain why and show how to circumvent the mathematical inconsistency.
Sum rule of the correlation functionSep 27 2004Feb 28 2005We discuss a sum rule satisfied by the correlation function of two particles with small relative momenta. The sum rule, which results from the completeness condition of the quantum states of the two particles, is first derived and then we check how it ... More
Senior Programmers: Characteristics of Elderly Users from Stack OverflowJul 03 2017In this paper we presents results of research about elderly users of Stack Overflow (Question and Answer portal for programmers). They have different roles, different main activities and different habits. They are an important part of the community, as ... More
Hydrodynamics with spin --- pseudo-gauge transformations, semi-classical expansion, and Pauli-Lubanski vectorNov 11 2018Recent progress in the formulation of relativistic hydrodynamics for particles with spin one-half is reviewed. We start with general arguments advising introduction of a tensor spin chemical potential that plays a role of the Lagrange multiplier coupled ... More
Proposal of a multiagent-based smart environment for the IoTApr 06 2014Jul 11 2014This work relates to context-awareness of things that belong to IoT networks. Preferences understood as a priority in selection are considered, and dynamic preference models for such systems are built. Preference models are based on formal logic, and ... More
Stochastically Incomplete Manifolds and GraphsOct 29 2009We survey geometric properties which imply the stochastic incompleteness of the minimal diffusion process associated to the Laplacian on manifolds and graphs. In particular, we completely characterize stochastic incompleteness for spherically symmetric ... More
The class of the affine line is a zero divisor in the Grothendieck ring: an improvementApr 22 2016Jul 21 2016Lev A. Borisov has shown that the class of the affine line is a zero divisor in the Grothendieck ring of algebraic varieties over complex numbers. We improve the final formula by removing a factor.
Enhanced TKIP Michael AttacksOct 23 2014This paper presents new attacks against TKIP within IEEE 802.11 based networks. Using the known Beck-Tews attack, we define schemas to con- tinuously generate new keystreams, which allow more and longer arbitrary packets to be injected into the network. ... More
Difference Principle and Black-hole ThermodynamicsJun 26 2009The heuristic principle that constructive dynamics may arise wherever there exists a difference, or gradient, is discussed. Consideration of black-hole entropy appears to provide a clue for setting a lower bound on any extensive measure of such collective ... More
The two-leg t-J ladder: a spin liquid generated by Gutzwiller projection of magnetic bandsApr 01 1998Apr 17 1998The ground state of the two-leg Heisenberg ladder is identified as an RVB type spin liquid, which is generated by Gutzwiller projection of tight-binding bands with flux pi per plaquet. Explicit trial wave functions for the magnon and hole excitations ... More
Landau Level Quantization on the SphereJan 20 2011Mar 06 2011It is well established that the Hilbert space for charged particles in a plane subject to a uniform magnetic field can be described by two mutually commuting ladder algebras. We propose a similar formalism for Landau level quantization involving two mutually ... More
On the linear dispersion--linear potential quantum oscillatorJan 28 2010We solve the bi-linear quantum oscillator H=v|p|+F|x| both quasi-classically and numerically.
Is electromagnetic gauge invariance spontaneously violated in superconductors?Mar 16 2005We aim to give a pedagogical introduction to those elementary aspects of superconductivity which are not treated in the classic textbooks. In particular, we emphasize that global U(1) phase rotation symmetry, and not gauge symmetry, is spontaneously violated, ... More
Denser Egyptian FractionsNov 18 1998An Egyptian fraction is a sum of distinct unit fractions (reciprocals of positive integers). We show that every rational number has Egyptian fraction representations where the number of terms is of the same order of magnitude as the largest denominator, ... More
Morse theory in the 1990'sApr 15 2001This is a survey article on Morse theory based on lectures to graduate students and advanced undergraduates. After a brief review of standard material, mostly without proofs, the Morse theory of complex Grassmannian manifolds is worked out in detail. ... More
Status of CMB observations in 2015Jun 10 2016Jun 15 2016The 2.725 K cosmic microwave background has played a key role in the development of modern cosmology by providing a solid observational foundation for constraining possible theories of what happened at very large redshifts and theoretical speculation ... More
A statistical inference course based on p-valuesJun 07 2016Introductory statistical inference texts and courses treat the point estimation, hypothesis testing, and interval estimation problems separately, with primary emphasis on large-sample approximations. Here I present an alternative approach to teaching ... More
On similarity of jet quenching and charmonia suppressionJun 02 2016We quantify the magnitude of the parton energy loss in jets in lead-lead collisions at the LHC. We extract the effective color factor characterizing the difference between the in-medium radiation of quark-initiated jets and gluon-initiated jets from the ... More
BW - Eye Ophthalmologic decision support system based on clinical workflow and data mining techniques-image registration algorithmDec 17 2013Blueworks - Medical Expert Diagnosis is developing an application, BWEye, to be used as an ophthalmology consultation decision support system. The implementation of this application involves several different tasks and one of them is the implementation ... More
AGB stars in the Local Group, and beyondJul 14 2004I summarize the current status of surveys for late-type M, and Carbon stars in the Local Group based on three different approaches that make use of the characteristics of these stars: spectral characteristics using narrow-band filters, infrared characteristics, ... More
Automorphisms of the 3-sphere that preserve a genus two Heegaard splittingJul 16 2003An updated proof of a 1933 theorem of Goeritz, exhibiting a finite set of generators for the group of automorphisms of the 3-sphere that preserve a genus two Heegaard splitting. The group is analyzed via its action on a certain connected 2-complex. (The ... More
Heegaard splittings of compact 3-manifoldsJul 24 2000An expository survey article on Heegaard splittings
Large photon number extraction from individual atoms trapped in an optical latticeNov 24 2010Mar 22 2011The atom-by-atom characterization of quantum gases requires the development of novel measurement techniques. One particularly promising new technique demonstrated in recent experiments uses strong fluorescent laser scattering from neutral atoms confined ... More
Fast (Multi-)Evaluation of Linearly Recurrent Sequences: Improvements and ApplicationsNov 08 2005For a linearly recurrent vector sequence P[n+1] = A(n) * P[n], consider the problem of calculating either the n-th term P[n] or L<=n arbitrary terms P[n_1],...,P[n_L], both for the case of constant coefficients A(n)=A and for a matrix A(n) with entries ... More
Real Hypercomputation and ContinuityAug 15 2005Feb 22 2006By the sometimes so-called 'Main Theorem' of Recursive Analysis, every computable real function is necessarily continuous. We wonder whether and which kinds of HYPERcomputation allow for the effective evaluation of also discontinuous f:R->R. More precisely ... More
Time's Arrow from the Multiverse Point of ViewAug 31 2006Jul 22 2014In this paper I suggest a possible explanation for the asymmetry of time. In the case that I study, the dynamical laws and the boundary conditions are symmetric, but the behavior of time is not. The underlying mechanism is statistical and closely related ... More