Results for "Joachim Weickert"

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The circular SiZer, inferred persistence of shape parameters and application to early stem cell differentiationApr 12 2014Jul 05 2016We generalize the SiZer of Chaudhuri and Marron (J. Amer. Statist. Assoc. 94 (1999) 807-823, Ann. Statist. 28 (2000) 408-428) for the detection of shape parameters of densities on the real line to the case of circular data. It turns out that only the ... More
Anisotropic osmosis filtering for shadow removal in imagesSep 17 2018We present an anisotropic extension of the isotropic osmosis model that has been introduced by Weickert et al.~(Weickert, 2013) for visual computing applications, and we adapt it specifically to shadow removal applications. We show that in the integrable ... More
Enhancing Patch-Based Methods with Inter-frame Connectivity for Denoising Multi-frame ImagesJun 17 2019The 3D block matching (BM3D) method is among the state-of-art methods for denoising images corrupted with additive white Gaussian noise. With the help of a novel inter-frame connectivity strategy, we propose an extension of the BM3D method for the scenario ... More
Pseudo-inverses of difference matrices and their application to sparse signal approximationApr 16 2015We derive new explicit expressions for the components of Moore-Penrose inverses of symmetric difference matrices. These generalized inverses are applied in a new regularization approach for scattered data interpolation based on partial differential equations. ... More
Algorithms for Piecewise Constant Signal ApproximationsMar 04 2019We consider the problem of finding optimal piecewise constant approximations of one-dimensional signals. These approximations should consist of a specified number of segments (samples) and minimise the mean squared error to the original signal. We formalise ... More
Algorithms for Piecewise Constant Signal ApproximationsMar 04 2019Jun 11 2019We consider the problem of finding optimal piecewise constant approximations of one-dimensional signals. These approximations should consist of a specified number of segments (samples) and minimise the mean squared error to the original signal. We formalise ... More
Algorithms for Piecewise Constant Signal ApproximationsMar 04 2019Mar 06 2019We consider the problem of finding optimal piecewise constant approximations of one-dimensional signals. These approximations should consist of a specified number of segments (samples) and minimise the mean squared error to the original signal. We formalise ... More
Compressing Flow Fields with Edge-aware Homogeneous Diffusion InpaintingJun 28 2019Motion estimation is an important component of video codecs and various applications in computer vision. Especially in video compression the compact representation of motion fields is crucial, as modern video codecs use them for inter frame prediction. ... More
Stable Backward Diffusion Models that Minimise Convex EnergiesMar 08 2019Backward diffusion processes appear naturally in image enhancement and deblurring applications. However, the inverse problem of backward diffusion is known to be ill-posed and straightforward numerical algorithms are unstable. So far, existing stabilisation ... More
Convex Regularization of Multi-Channel Images Based on Variants of the TV-ModelApr 04 2018We discuss existence and regularity results for multi-channel images in the setting of isotropic and anisotropic variants of the TV-model.
Space-Filling Curve Indices as Acceleration Structure for Exemplar-Based InpaintingDec 18 2017Exemplar-based inpainting is the process of reconstructing missing parts of an image by searching the remaining data for patches that fit seamlessly. The image is completed to a plausible-looking solution by repeatedly inserting the patch that is the ... More
Existence Theory for the EED Inpainting ProblemJun 11 2019We establish an existence theory for an elliptic boundary value problem in image analysis known as edge-enhancing diffusion (EED) inpainting. The EED inpainting problem aims at restoring missing data in an image as steady state of a nonlinear anisotropic ... More
Optimising Spatial and Tonal Data for PDE-based InpaintingJun 15 2015Some recent methods for lossy signal and image compression store only a few selected pixels and fill in the missing structures by inpainting with a partial differential equation (PDE). Suitable operators include the Laplacian, the biharmonic operator, ... More
Universal signatures of the metamagnetic quantum critical endpoint: Application to CeRu2Si2Dec 18 2009May 04 2010A quantum critical endpoint related to a metamagnetic transition causes distinct signatures in the thermodynamic quantities of a compound. We argue that, irrespective of the microscopic details of the considered material, the diverging differential susceptibility ... More
Observation of two critical points linked to the high field phase B in CeCu2Si2Mar 12 2018Jul 13 2018We present thermal expansion and magnetostriction measurements on a CeCu2Si2 single crystal of A/S-type up to 17.9T magnetic field applied along the crystallographic a-direction (Delta L ll a ll H) and down to 0.015K temperature. We identify clear thermodynamic ... More
The Product Life Cycle of Durable GoodsSep 05 2011Sep 11 2015A dynamic model of the product lifecycle of (nearly) homogeneous durables in polypoly markets is established. It describes the concurrent evolution of the unit sales and price of durable goods. The theory is based on the idea that the sales dynamics is ... More
Polynomial functors and combinatorial Dyson-Schwinger equationsDec 09 2015Feb 04 2016We present a general abstract framework for combinatorial Dyson-Schwinger equations, in which combinatorial identities are lifted to explicit bijections of sets, and more generally equivalences of groupoids. Key features of combinatorial Dyson-Schwinger ... More
Efficient numerical diagonalization of hermitian 3x3 matricesOct 24 2006Jul 04 2008A very common problem in science is the numerical diagonalization of symmetric or hermitian 3x3 matrices. Since standard "black box" packages may be too inefficient if the number of matrices is large, we study several alternatives. We consider optimized ... More
Interface dynamics of microscopic cavities in waterApr 02 2007An analytical description of the interface motion of a collapsing nanometer-sized spherical cavity in water is presented by a modification of the Rayleigh-Plesset equation in conjunction with explicit solvent molecular dynamics simulations. Quantitative ... More
Introduction to Step Dynamics and Step InstabilitiesMay 04 2004This paper provides an elementary introduction to the basic concepts used in describing epitaxial crystal growth in terms of the thermodynamics and kinetics of atomic steps. Selected applications to morphological instabilities of stepped surfaces are ... More
Tempo and mode in quasispecies evolutionMar 21 2001Evolutionary dynamics in an uncorrelated rugged fitness landscape is studied in the framework of Eigen's molecular quasispecies model. We consider the case of strong selection, which is analogous to the zero temperature limit in the equivalent problem ... More
Scaling regimes for second layer nucleationAug 30 2000Nucleation on top of two-dimensional islands with step edge barriers is investigated using scaling arguments. The nucleation rate is expressed in terms of three basic time scales: The time interval between deposition events, the residence time of atoms ... More
Spiral growth, two-dimensional nucleation, and the Ehrlich-Schwoebel effectSep 13 2007Frank's prediction of the spiral growth mode in 1949 defined a pivotal moment in the history of crystal growth. In recent decades the topic has received less attention, and instead we have seen a resurrection of two-dimensional nucleation theory in the ... More
Four Lectures on the Physics of Crystal GrowthJun 21 2002Several aspects of the theory of epitaxial crystal growth from atomic or molecular beams are developed from the perspective of statistical physics. Lectures are devoted to the rate equation theory of two-dimensional nucleation and its limitations; the ... More
Coarsening of vortex ripples in sandAug 28 2001The coarsening of an array of vortex ripples prepared in an unstable state is discussed within the framework of a simple mass transfer model first introduced by K.H. Andersen et al. [Phys. Rev. E 63, 066308 (2001)]. Two scenarios for the selection of ... More
Kinematical versus Dynamical Contractions of the de Sitter Lie algebrasJun 04 2014Jul 13 2015We explicit and clarify better the contraction method that Bacry and Levy-Leblond\cite{jmll} used to link all the kinematical Lie groups. Firstly, we use the kinematical parameters: the speed $c$ of light, the radius $r$ of the universe and the period ... More
Gabor analysis for a broad class of quasi-Banach modulation spacesApr 03 2014Sep 06 2014We extend the Gabor analysis in \cite{GaSa} to a broad class of modulation spaces, allowing more general mixed quasi-norm estimates and weights in the definition of the modulation space quasi-norm. For such spaces we deduce invariance and embedding properties, ... More
Elementary components of Hilbert schemesOct 17 2017Feb 01 2019We generalize the Bialynicki-Birula decomposition to singular schemes and apply it to the Hilbert scheme of points on an affine space. We find an infinite family of small, elementary and generically smooth components of the Hilbert scheme of points of ... More
Contracting Maps and Scalar CurvatureDec 31 2018We explain how to derive largeness constraints in scalar curvature geometry using some basic splitting results and the potential theory on singular area minimizing hypersurfaces. This includes a variety of results like the non-existence of positive scalar ... More
Potential Theory on Minimal Hypersurfaces II: Hardy Structures and Schrödinger OperatorsOct 07 2018We extend the potential theory on almost minimzers from Part 1. We introduce so-called Hardy structures to study many classical operators using the tools from part 1. Furthermore, we show that for a naturally defined operator L, minimal growth of positive ... More
Semigroup C*-algebras and toric varietiesMar 21 2017Let S be a finitely generated subsemigroup of Z^2. We derive a general formula for the K-theory of the left regular C*-algebra for S.
Continuity of Gevrey-Hörmander pseudo-differential operators on modulation spacesOct 31 2017May 22 2018Let $s\ge 1$, $\omega ,\omega_0\in \mathscr P_{E,s}^0$, $a\in \Gamma _{s}^{(\omega_0)}$, and let $\mathscr B$ be a suitable invariant quasi-Banach function space, Then we prove that the pseudo-differential operator $\operatorname{Op} (a)$ is continuous ... More
Matrix parameterized pseudo-differential calculi on modulation spacesApr 05 2016Sep 25 2016We consider a broad matrix parameterized family of pseudo-differential calculi, containing the usual Shubin's family of pseudo-differential calculi, parameterized by real numbers. We show that continuity properties in the framework of modulation space ... More
Science on YouTube: What users find when they search for climate science and climate manipulationFeb 08 2016Apr 18 2016Online video-sharing sites such as YouTube are very popular and also used by a lot of people to obtain knowledge and information, also on science, health and technology. Technically they could be valuable tools for the public communication of science ... More
A promise checked is a promise kept: Inspection TestingMar 19 2018Jun 03 2018Occasionally, developers need to ensure that the compiler treats their code in a specific way that is only visible by inspecting intermediate or final compilation artifacts. This is particularly common with carefully crafted compositional libraries, where ... More
On the number of cyclic transitive subgroups of a permutation groupJan 26 2015Feb 09 2015We prove an upper bound for the number of cyclic transitive subgroups in a finite permutation group and clarify the structure of the groups for which this bound becomes sharp. We also give an application in the theory of number fields.
Stochastic Calculus with respect to Gaussian ProcessesAug 05 2014Feb 08 2018Stochastic integration with respect to Gaussian processes, such as fractional Brownian motion (fBm) or multifractional Brownian motion (mBm), has raised strong interest in recent years, motivated in particular by applications in finance, Internet traffic ... More
Form factor (Fourier shape transform) of polygon and polyhedronMar 01 2017The Fourier transform of the indicator function of arbitrary polygons and polyhedra is computed for complex wavevectors. Using the divergence theorem and Stokes' theorem, closed expressions are obtained. Apparent singularities, all removable, are discussed ... More
C*-algebras associated with algebraic actionsSep 23 2015Dec 03 2015This is a survey of work in which the author was involved in recent years. We consider C*-algebras constructed from representations of one or several algebraic endomorphisms of a compact abelian group - or, dually, of a discrete abelian group. In our ... More
An analytic KAM-TheoremMay 02 2007We prove an analytic KAM-Theorem, which is used in [1], where the differential part of KAM-theory is discussed. Related theorems on analytic KAM-theory exist in the literature (e. g., among many others, [7], [8], [13]). The aim of the theorem presented ... More
Loop subgroups of F_r and the image of their stabilizer subgroups in GL_r(Z)Dec 13 2010Dec 24 2011For a representative class of subgroups of F_r, the image of their stabilizer subgroup under the action of Aut(F_r) in GL_r(Z) is calculated.
Weak identity arrows in higher categoriesJul 06 2005Nov 28 2005There are a dozen definitions of weak higher categories, all of which loosen the notion of composition of arrows. A new approach is presented here, where instead the notion of identity arrow is weakened -- these are tentatively called fair categories. ... More
Yank and Hooke's constant group theoreticallyJun 22 2002We study the second central extension of the (1+1) Aristotle Lie.We find that the first central extension admit four orbits on the dual of second central extension of the (1+1) Aristotle Lie group.The generic orbit is characterised by a Hooke's constant ... More
Deformations of zero-dimensional schemes and applicationsJul 30 2013Apr 02 2014In this thesis we consider the geometry of the Hilbert scheme of points in P^n, concentrating on the locus of points corresponding to the Gorenstein subschemes of P^n. New results are given, most importantly we provide tools for constructing flat families ... More
Data types with symmetries and polynomial functors over groupoidsOct 02 2012Polynomial functors are useful in the theory of data types, where they are often called containers. They are also useful in algebra, combinatorics, topology, and higher category theory, and in this broader perspective the polynomial aspect is often prominent ... More
Method LACJul 29 2005This is a paper which present a mnemotechnical method that we call LAC for Lists, Arrangements and Combinations. It can help students or any one to recollect formulae from combinatorial theory ([1],[2],[3],[4]) without an a priori memorization of them. ... More
Global Regularity of Wave Maps from R^{3+1} to H^2Mar 14 2002We consider Wave Maps with smooth compactly supported initial data of small H^{{3/2}}-norm from R^{3+1} to the hyperbolic plane and show that they stay smooth globally in time. Our methods are based on the introduction of a global Coulomb Gauge as in ... More
Some Remarks about the Complexity of Epidemics ManagementMay 07 2017Jun 18 2017Recent outbreaks of Ebola, H1N1 and other infectious diseases have shown that the assumptions underlying the established theory of epidemics management are too idealistic. For an improvement of procedures and organizations involved in fighting epidemics, ... More
On the mod-$p$ distribution of discriminants of $G$-extensionsFeb 15 2019This paper was motivated by a recent paper by Krumm and Pollack investigating modulo-$p$ behaviour of quadratic twists with rational points of a given hyperelliptic curve, conditional on the abc-conjecture. We extend those results to twisted Galois covers ... More
Computation of Hurwitz spaces and new explicit polynomials for almost simple Galois groupsDec 17 2015We compute the first explicit polynomials with Galois groups $G=P\Gamma L_3(4)$, $PGL_3(4)$, $PSL_3(4)$ and $PSL_5(2)$ over $\mathbb{Q}(t)$. Furthermore we compute the first examples of totally real polynomials with Galois groups $PGL_2(11)$, $PSL_3(3)$, ... More
An upper bound for the Waring rank of a formMay 29 2013In this paper we introduce the open Waring rank of a form of degree d in n variables and prove the that this rank in bounded from above by \binom{n+d-2}{d-1} - \binom{n+d-6}{d-3} whenever n, d >= 3. This proves the same upper bound for the classical Waring ... More
Attractor Networks on Complex Flag ManifoldsDec 13 2008Robbin and Salamon showed that attractor-repellor networks and Lyapunov maps are equivalent concepts and illustrate this with the example of linear flows on projective spaces. In these examples the fixed points are linearly ordered with respect to the ... More
A remark on the effect of random singular two-particle interactionsJul 04 2017In this note we study a two-particle bound system (molecule) moving on the positive half-line under the influence of randomly distributed singular two-particle interactions generated by a Poisson process. We give a rigorous definition of the underlying ... More
Stability of Spherically Symmetric Wave MapsMar 02 2005We study Wave Maps from R^{2+1} to the hyperbolic plane with smooth compactly supported initial data which are close to smooth spherically symmetric ones with respect to some H^{1+\mu}, \mu>0. We show that such Wave Maps don't develop singularities and ... More
On the existence of weak solutions of a thermistor system with p-Laplacian type equation: the unsteady caseApr 25 2016We consider an unsteady thermistor system with a p-Laplace type equation for the electrostatic potential.
Pathologies on the Hilbert scheme of pointsDec 20 2018We prove that the Hilbert scheme of points on a higher dimensional affine space is non-reduced and has components lying entirely in characteristic p for all primes p. In fact, we show that Vakil's Murphy's Law holds up to retraction for this scheme. Our ... More
Mossbauer neutrinos in quantum mechanics and quantum field theoryApr 28 2009Jun 12 2009We demonstrate the correspondence between quantum mechanical and quantum field theoretical descriptions of Mossbauer neutrino oscillations. First, we compute the combined rate $\Gamma$ of Mossbauer neutrino emission, propagation, and detection in quantum ... More
Free Choice Petri Nets without frozen tokens and Bipolar Synchronization SystemsSep 17 2006Sep 10 2007Bipolar synchronization systems (BP-systems) constitute a class of coloured Petri nets, well suited for modeling the control flow of discrete, dynamical systems. Every BP-system has an underlying ordinary Petri net, which is a T-system. Moreover, it has ... More
Comment on "Dynamic Scaling of Non-Euclidean Interfaces" [arXiv:0804.1898]Oct 27 2008Feb 23 2009This is the revised version of a Comment on a paper by C. Escudero (Phys. Rev. Lett. 100, 116101, 2008; arXiv:0804.1898).
Lonely adatoms in spaceFeb 14 2003There is a close relation between the problems of second layer nucleation in epitaxial crystal growth and chemical surface reactions, such as hydrogen recombination, on interstellar dust grains. In both cases standard rate equation analysis has been found ... More
Stochastic Calculus with respect to Gaussian ProcessesAug 05 2014May 20 2015Stochastic integration with respect to Gaussian processes, such as fractional Brownian motion (fBm) or multifractional Brownian motion (mBm), has raised strong interest in recent years, motivated in particular by applications in finance, Internet traffic ... More
Canonical transformations for fermions in superanalysisApr 08 2013Apr 29 2013Canonical transformations (Bogoliubov transformations) for fermions with an infinite number of degrees of freedom are studied within a calculus of superanalysis. A continuous representation of the orthogonal group is constructed on a Grassmann module ... More
Local finite dimensional Gorenstein k-algebras having Hilbert function (1,5,5,1) are smoothableDec 03 2012Let k be an algebraically closed field of characteristic 0. The question of irreducibility of the punctual Hilbert scheme Hilb_d P^n and its Gorenstein locus for various d was studied in [CEVV8, CN9, CN10, CN11]. In this short paper we prove that the ... More
The International Linear Collider: Prospects and Possible TimelinesJan 29 2019The case for the International Linear Collider and the prospects for its realisation as well as possible timelines are discussed.
Minimal Smoothings of Area Minimizing ConesOct 07 2018In this paper we show that every area minimizing cone C^{n-1} in R^n can be approximated by entirely smooth area minimizing hypersurfaces. This extensively uses hyperbolic unfoldings of such hypersurfaces and the resulting potential theory for the Jacobi ... More
Non-parametricity of rational translates of regular Galois extensionsDec 23 2016Jun 11 2017We generalize a result of F.\ Legrand about the existence of non-parametric Galois extensions for a given group $G$. More precisely, for a $K$-regular Galois extension $F|K(t)$, we consider the translates $F(s)|K(s)$ by an extension $K(s)|K(t)$ of rational ... More
Tensor products for Gelfand-Shilov and Pilipovi{ć} distribution spacesAug 20 2018We show basic properties on tensor products for Gelfand-Shilov distributions and Pilipovi{\'c} distributions. This also includes the Fubbini's property of such tensor products. We also apply the Fubbini property to deduce some properties for short-time ... More
The sufficiently smart compiler is a theorem proverMay 21 2018That the Haskell Compiler GHC is capable of proving non-trivial equalities between Haskell code, by virtue of its aggressive optimizer, in particular the term rewriting engine in the simplifier. We demonstrate this with a surprising little code in a GHC ... More
Schatten properties, nuclearity and minimality of shift invariant spacesMay 10 2016Nov 10 2016We extend Feichtinger's minimality property on smallest non-trivial time-frequency shift invariant Banach spaces, to the quasi-Banach case. Analogous properties are deduced for certain matrix classes. We use these results to prove that $\operatorname{Op}(a)$ ... More
Semi-continuous convolutions on weakly periodic Lebesgue spacesFeb 13 2018We deduce mixed quasi-norm estimates of Lebesgue types on semi-continuous convolutions between sequences and functions which may be periodic or possess a weaker form of periodicity in certain directions. In these directions, the Lebesgue quasi-norms are ... More
The Grunwald problem and specialization of families of regular Galois extensionsOct 16 2017Feb 28 2018We investigate specializations of infinite families of regular Galois extensions over number fields. The problem to what extent the local behaviour of specializations of one single regular Galois extension can be prescribed has been investigated by D\`ebes ... More
Stochastic Calculus with respect to Gaussian Processes: Part IMar 24 2017Feb 14 2018Stochastic integration \textit{wrt} Gaussian processes has raised strong interest in recent years, motivated in particular by its applications in Internet traffic modeling, biomedicine and finance. The aim of this work is to define and develop a White ... More
Skin Structures in Scalar Curvature GeometryDec 27 2015This is the third in a series of papers on the geometry and analysis of singular area minimizing hypersurfaces. We show how to derive obstruction and structure theories for scalar curvature constraints without imposing dimensional or topological restrictions ... More
Evolutionary Model of Stock MarketsMay 15 2015The paper presents an evolutionary economic model for the price evolution of stocks. Treating a stock market as a self-organized system governed by a fast purchase process and slow variations of demand and supply the model suggests that the short term ... More
On rational functions with monodromy group $M_{11}$Mar 23 2015Dec 14 2015We compute new polynomials with Galois group $M_{11}$ over $\mathbb{Q}(t)$. These polynomials stem from various families of covers of $\mathbb{P}^1\mathbb{C}$ ramified over at least 4 points. Each of these families has features that make a detailed study ... More
Gravitational potential energy group theoreticallyApr 30 2003May 05 2003We show by symplectically realizing the one spatial Aristotle Lie group that the hamiltonian of the associated elementary system consist of a gravitational energy only. No kinetic term.
From Möbius inversion to renormalisationSep 04 2018This paper traces a straight line from classical M\"obius inversion to Hopf-algebraic perturbative renormalisation. This line, which is logical but not entirely historical, consists of just a few main abstraction steps, and some intermediate steps dwelled ... More
On the number of isolated eigenvalues of a pair of particles in a quantum wireDec 31 2018In this note we consider a pair of particles moving on the positive half-line with the pairing generated by a hard-wall potential. This model was first introduced in [arXiv:1604.06693] and later applied to investigate condensation of pairs of electrons ... More
Elementary components of Hilbert schemesOct 17 2017Apr 07 2019We generalize the Bialynicki-Birula decomposition to singular schemes and apply it to the Hilbert scheme of points on an affine space. We find an infinite family of small, elementary and generically smooth components of the Hilbert scheme of points of ... More
Arason's filtration of the Witt group of dyadic valued fieldsJan 03 2019Jan 04 2019Generalizing a theorem of Springer, we construct an extended Arason filtration by subgroups for the Witt group of quadratic forms of a general valued field, relating these subgroups with Witt-like groups of the residue field, in arbitrary characteristic. ... More
Classifying local Artinian Gorenstein algebrasNov 25 2015Oct 12 2016The classification of local Artinian Gorenstein algebras is equivalent to the study of orbits of a certain non-reductive group action on a polynomial ring. We give an explicit formula for the orbits and their tangent spaces. We apply our technique to ... More
Recursion for twisted descendants and characteristic numbers of rational curvesFeb 03 1999On a space of stable maps, the psi classes are modified by subtracting certain boundary divisors. The top products of modified psi classes, usual psi classes, and classes pulled back along the evaluation maps are called twisted descendants; it is shown ... More
Cospan construction of the graph category of Borisov and ManinNov 30 2016Dec 13 2016It is shown how the graph category of Borisov and Manin can be constructed from (a variant of) the graph category of Joyal and Kock, essentially by reversing the generic morphisms. More precisely, the morphisms in the Borisov-Manin category are exhibited ... More
Images of function and distribution spaces under the Bargmann transformSep 18 2014Jun 08 2016We consider a broad family of test function spaces and their dual (distribution) space. The family includes Gelfand-Shilov spaces, a family of test function spaces introduced by S. Pilipovic. We deduce different characterizations of such spaces, especially ... More
Morphisms of Coloured Petri NetsAug 07 2006We introduce the concept of a morphism between coloured nets. Our definition generalizes Petris definition for ordinary nets. A morphism of coloured nets maps the topological space of the underlying undirected net as well as the kernel and cokernel of ... More
Products on Schatten-von Neumann classes and modulation spacesFeb 16 2009We consider modulation space and spaces of Schatten-von Neumann symbols where corresponding pseudo-differential operators map one Hilbert space to another. We prove H\"older-Young and Young type results for such spaces under dilated convolutions and multiplications. ... More
Comment on ``Determination of Interlayer Diffusion Parameters for Ag(111)''Aug 30 2000Mar 15 2001A Comment on PRL 85, 1480 (2000) by K.R. Roos and M.C. Tringides.
Aperiodic and correlated disorder in XY-chains: exact resultsAug 21 1998We study thermodynamic properties, specific heat and susceptibility, of XY quantum chains with coupling constants following arbitrary substitution rules. Generalizing an exact renormalization group transformation, originally formulated for Ising quantum ... More
Proposed STAR Time of Flight Readout Electronics and DAQMay 30 2003The Time-of-Flight system is a proposed addition to the STAR detector currently installed at RHIC. The proposal is based on a new technology called the Multi-gap Resistive Plate Chamber (MRPC), and consists of approximately 23,000 channels of detectors ... More
Discrete Quantum Walk on a Line with Two Entangled ParticlesMay 19 2012A review of discrete quantum walk with two particle is given. The use of different states encountered in identical particle, and the idea of entanglement and superposition is explored to explored the interesting dynamics of two particle quantum walk. ... More
Quillen's work on the foundations of cyclic cohomologyFeb 27 2012We give a survey of Quillen's contributions, apart from the very first joint paper with Loday, to the area of cyclic homology.
On Truncation of irreducible representations of Chevalley groupsJul 18 2011Jun 13 2013We prove part of a higher rank analogue of the Mazur-Gouvea Conjecture. More precisely, let $\tilde{\bf G}$ be a connected, reductive ${\Bbb Q}$-split group and let $\Gamma$ be an arithmetic subgroup of $\tilde{\bf G}$. We show that the dimension of the ... More
dup -- Explicit un-sharing in HaskellJul 09 2012We propose two operations to prevent sharing in Haskell that do not require modifying the data generating code, demonstrate their use and usefulness, and compare them to other approaches to preventing sharing. Our claims are supported by a formal semantics ... More
The Bargmann transform on a broad family of Banach spaces, with applications to Toeplitz and pseudo-differential operatorsFeb 02 2011Jun 22 2011We investigate mapping properties for the Bargmann transform on modulation spaces whose weights and their reciprocals are allowed to grow faster than exponentials. We prove that this transform is isometric and bijective from modulation spaces to convenient ... More
How interface geometry dictates water's thermodynamic signature in hydrophobic associationApr 29 2011As a common view the hydrophobic association between molecular-scale binding partners is supposed to be dominantly driven by entropy. Recent calorimetric experiments and computer simulations heavily challenge this established paradigm by reporting that ... More
Conjugation of Hilbert modular forms and trace formulaFeb 11 2011We describe (in a representation theoretic setting) a simple comparison of trace formulas, which implies that the conjugate of a Hilbert modular form $f$ by an automorphism of ${\Bbb C}$ again is a Hilbert modular form of the same level and conjugate ... More
Fourier Transform of the Stretched Exponential Function: Analytic Error Bounds, Double Exponential Transform, and Open-Source Implementation libkwwNov 25 2009Sep 01 2012The C library \texttt{libkww} provides functions to compute the Kohlrausch-Williams-Watts function, i.e.\ the Laplace-Fourier transform of the stretched (or compressed) exponential function $\exp(-t^\beta)$ for exponents $\beta$ between 0.1 and 1.9 with ... More
An Optimal Algorithm for the Indirect Covering Subtree ProblemFeb 02 2010We consider the indirect covering subtree problem (Kim et al., 1996). The input is an edge weighted tree graph along with customers located at the nodes. Each customer is associated with a radius and a penalty. The goal is to locate a tree-shaped facility ... More
Polynomial functors and combinatorial Dyson-Schwinger equationsDec 09 2015Oct 03 2016We present a general abstract framework for combinatorial Dyson-Schwinger equations, in which combinatorial identities are lifted to explicit bijections of sets, and more generally equivalences of groupoids. Key features of combinatorial Dyson-Schwinger ... More
Heavy Baryon Chiral Perturbation Theory and the Spin 3/2 Delta ResonancesJun 27 1996Heavy baryon chiral perturbation theory is briefly reviewed, paying particular attention to the role of the spin 3/2 delta resonances. The concept of resonance saturation for the baryonic sector is critically discussed. Starting from a relativistic formulation ... More