Results for "Wolfgang Mauerer"

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McFSM: Globally Taming Complex SystemsFeb 25 2017Industrial computing devices, in particular cyber-physical, real-time and safety-critical systems, focus on reacting to external events and the need to cooperate with other devices to create a functional system. They are often implemented with languages ... More
Recent developments in quantum key distribution: theory and practiceDec 04 2007Jan 29 2008Quantum key distribution is among the foremost applications of quantum mechanics, both in terms of fundamental physics and as a technology on the brink of commercial deployment. Starting from principal schemes and initial proofs of unconditional security ... More
Evolutionary Trends of Developer Coordination: A Network ApproachOct 23 2015Oct 19 2016Software evolution is a fundamental process that transcends the realm of technical artifacts and permeates the entire organizational structure of a software project. By means of a longitudinal empirical study of 18 large open-source projects, we examine ... More
The List is the Process: Reliable Pre-Integration Tracking of Commits on Mailing ListsFeb 08 2019A considerable corpus of research on software evolution focuses on mining changes in software repositories, but omits their pre-integration history. We present a novel method for tracking this otherwise invisible evolution of software changes on mailing ... More
Multi-mode states in decoy-based quantum key distribution protocolsJan 29 2009Every security analysis of quantum key distribution (QKD) relies on a faithful modeling of the employed quantum states. Many photon sources, like for instance a parametric down conversion (PDC) source, require a multi-mode description, but are usually ... More
A modular framework for randomness extraction based on Trevisan's constructionDec 03 2012Informally, an extractor delivers perfect randomness from a source that may be far away from the uniform distribution, yet contains some randomness. This task is a crucial ingredient of any attempt to produce perfectly random numbers---required, for instance, ... More
Evolutionary Trends of Developer Coordination: A Network ApproachOct 23 2015Software evolution is a fundamental process that transcends the realm of technical artifacts and permeates the entire organizational structure of a software project. By means of a longitudinal empirical study of 18 large open-source projects, we examine ... More
Spectral structure and decompositions of optical states, and their applicationsSep 01 2006Mar 04 2008We discuss the spectral structure and decomposition of multi-photon states. Ordinarily `multi-photon states' and `Fock states' are regarded as synonymous. However, when the spectral degrees of freedom are included this is not the case, and the class of ... More
Observing Custom Software Modifications: A Quantitative Approach of Tracking the Evolution of Patch StacksJul 04 2016Modifications to open-source software (OSS) are often provided in the form of "patch stacks" - sets of changes (patches) that modify a given body of source code. Maintaining patch stacks over extended periods of time is problematic when the underlying ... More
Theory of quantum frequency conversion and type-II parametric down-conversion in the high-gain regimeOct 31 2012May 24 2013Frequency conversion (FC) and type-II parametric down-conversion (PDC) processes serve as basic building blocks for the implementation of quantum optical experiments: type-II PDC enables the efficient creation of quantum states such as photon-number states ... More
Look Mum, no VM Exits! (Almost)May 19 2017Multi-core CPUs are a standard component in many modern embedded systems. Their virtualisation extensions enable the isolation of services, and gain popularity to implement mixed-criticality or otherwise split systems. We present Jailhouse, a Linux-based, ... More
How Colors Influence Numbers: Photon Statistics of Parametric DownconversionDec 18 2008Parametric downconversion (PDC) is a technique of ubiquitous experimental significance in the production of non-classical, photon-number correlated twin beams. Standard theory of PDC as a two-mode squeezing process predicts and homodyne measurements observe ... More
Classifying Developers into Core and Peripheral: An Empirical Study on Count and Network MetricsApr 04 2016Knowledge about the roles developers play in a software project is crucial to understanding the project's collaborative dynamics. Developers are often classified according to the dichotomy of core and peripheral roles. Typically, operationalizations based ... More
A Dual Model of Open Source License GrowthAug 25 2014Every open source project needs to decide on an open source license. This decision is of high economic relevance: Just which license is the best one to help the project grow and attract a community? The most common question is: Should the project choose ... More
Assessing Solution Quality of 3SAT on a Quantum Annealing PlatformFeb 13 2019When solving propositional logic satisfiability (specifically 3SAT) using quantum annealing, we analyze the effect the difficulty of different instances of the problem has on the quality of the answer returned by the quantum annealer. A high-quality response ... More
A Hybrid Solution Method for the Capacitated Vehicle Routing Problem Using a Quantum AnnealerNov 18 2018The Capacitated Vehicle Routing Problem (CVRP) is an NP-optimization problem (NPO) that has been of great interest for decades for both, science and industry. The CVRP is a variant of the vehicle routing problem characterized by capacity constrained vehicles. ... More
A Hybrid Solution Method for the Capacitated Vehicle Routing Problem Using a Quantum AnnealerNov 18 2018Jun 14 2019The Capacitated Vehicle Routing Problem (CVRP) is an NP-optimization problem (NPO) that has been of great interest for decades for both, science and industry. The CVRP is a variant of the vehicle routing problem characterized by capacity constrained vehicles. ... More
A twisted Bass-Heller-Swan decomposition for the algebraic K-theory of additive categoriesSep 05 2013Jun 01 2015We prove a twisted Bass-Heller-Swan decomposition for both the connective and the non-connective K-theory spectrum of additive categories.
Non-connective K- and Nil-spectra of additive categorieMar 06 2013Sep 04 2013We present an elementary construction of the non-connective algebraic K-theory spectrum associated to an additive category following the contracted functor approach due to Bass. It comes with a universal property that easily allows us to identify it with ... More
Splitting the relative assembly map, Nil-terms and involutionsJan 12 2015Oct 06 2015We show that the relative Farrell-Jones assembly map from the family of finite subgroups to the family of virtually cyclic subgroups for algebraic K-theory is split injective in the setting where the coefficients are additive categories with group action. ... More
Simplicial Differential Calculus, Divided Differences, and Construction of Weil FunctorsSep 13 2010Jan 11 2011We define a simplicial differential calculus by generalizing divided differences from the case of curves to the case of general maps, defined on general topological vector spaces, or even on modules over a topological ring K. This calculus has the advantage ... More
Probing the MSSM flavor structure with low energy CP violationSep 15 2009We report on an extensive analysis of FCNC and CPV effects in SUSY theories. We present results for Delta F=2 and Delta F=1 processes governed by b --> s transitions both in the low and high tanbeta regime, focussing in particular on S_psi_phi, the phase ... More
On Calibrating Stochastic Volatility Models with time-dependent ParametersOct 06 2010We consider stochastic volatility models using piecewise constant parameters. We suggest a hybrid optimization algorithm for fitting the models to a volatility surface and provide some numerical results. Finally, we provide an outlook on how to further ... More
Strain mediated adatom stripe morphologies on Cu<111> simulatedJul 27 2012Jan 29 2013Substrate strain mediated adatom configurations on Cu<111> surfaces have been simulated in a coverage range up to nearly 1 monolayer. Interacting adatoms occupy positions on a triangular lattice in two dimensions. The elastic interaction is taken from ... More
Strain Induced Adatom CorrelationsMar 10 2012A Born-Green-Yvon type model for adatom density correlations is combined with a model for adatom interactions mediated by the strain in elastic anisotropic substrates. The resulting nonlinear integral equation is solved numerically for coverages from ... More
The most powerful particles in the Universe: a cosmic smashMay 06 2013This year we are celebrating 101 years since the discovery of cosmic rays. They are whizzing all around the Universe, and they occur at very different energies, including the highest particle energies that exist. However, theory predicts an abrupt suppression ... More
Flavor Changing Neutral Current Processes in a SO(10) SUSY GUT with Family SymmetryOct 08 2007We report on a detailed analysis of a SO(10) SUSY GUT model of Dermisek and Raby (DR) with a D3 family symmetry. The model is completely specified in terms of only 24 parameters and is able to successfully describe both quark and lepton masses and mixings, ... More
Supersymmetry and other beyond the Standard Model physics: Prospects for determining mass, spin and CP propertiesDec 10 2008The prospects of measuring masses, spin and CP properties within Supersymmetry and other beyond the Standard Model extensions at the LHC are reviewed. Emphasis is put on models with missing transverse energy due to undetected particles, as in Supersymmetry ... More
Westerlund 1 and its Galactic siblings -Observation confronts TheoryMar 13 2008Because of their large number of stars spread over the entire stellar mass spectrum, starburst clusters are highly suitable to benchmark and calibrate star formation models and theories. Among the handful of Galactic starburst clusters, Westerlund 1 with ... More
Full Salpeter Equation with Confining Interactions: Analytic Stability ProofOct 30 2008The most popular 3-dimensional reduction of the Bethe-Salpeter formalism for the description of bound states within quantum field theory is the Salpeter equation, found as the instantaneous limit of the Bethe-Salpeter framework if allowing, in addition, ... More
Light scalar meson spectrumNov 23 2001We discuss the classification of the light scalar mesons with mass below 2 GeV into q qbar nonets and glueballs. The information on production and decay of these states, in particular recent information on f_0(980), f_0(400-1200) (or sigma(600)) and f_0(1500) ... More
Scalar mesons: in search of the lightest glueballSep 20 2006According to the QCD expectations the lightest glueball should be a scalar particle (J^{PC}=0^{++}). Different scenarios have been considered for a classification of these states but -- despite considerable progress in recent years -- the experimental ... More
Dynamical modeling and the interactions with the ISMSep 22 2011This paper is a review of some of the recent modeling efforts to improve our understanding of structure formation and evolution of planetary nebulae including their interaction with the interstellar medium. New propositions have been made for the formation ... More
The Calculus of Expected Loss: Backtesting Parameter-Based Expected Loss in a Basel II FrameworkNov 21 2012Aug 08 2013The dependency structure of credit risk parameters is a key driver for capital consumption and receives regulatory and scientific attention. The impact of parameter imperfections on the quality of expected loss (EL) in the sense of a fair, unbiased estimate ... More
On the Solvability of Maxwell's EquationsSep 13 2012Complementing a study which was published in this journal in 2005, we present explicit calculations of fields predicted by Maxwell's equations both in Lorenz and in Coulomb gauge. Analytic expressions are obtainable, when the source of the fields is an ... More
On Scalar and Vector Potentials for the Nonlinear Electromagnetic ForcesMay 08 2008The potential concept that is successful in classical electrodynamics should also be applicable to the nonlinear electromagnetic forces acting on matter. The obvious method of determining these potentials should be provided by Helmholtz's theorem. It ... More
Electroweak Precision Tests with a Future Linear ColliderOct 26 2001Future high energy linear electron positron colliders with centre-of-mass enegies between 90 and 1000 GeV offer a unique opportunity to study precisely the Standard Model and phenomena from new physics. Most important, the mechanism of electroweak symmetry ... More
Application of Microlocal Analysis to the Theory of Quantum Fields Interacting with a Gravitational FieldJan 10 1997It is explained how techniques from microlocal analysis can be used to settle some long-standing questions that arise in the study of the interaction of quantum matter fields with a classical gravitational background field.
Adiabatic Vacua and Hadamard States for Scalar Quantum Fields on Curved SpacetimeJul 19 1995Quasifree states of a linear Klein-Gordon quantum field on globally hyperbolic spacetime manifolds are considered. Using techniques from the theory of pseudodifferential operators and wavefront sets on manifolds a criterion for a state to be an Hadamard ... More
Robust Processing of Natural LanguageJul 13 1995Jul 14 1995Previous approaches to robustness in natural language processing usually treat deviant input by relaxing grammatical constraints whenever a successful analysis cannot be provided by ``normal'' means. This schema implies, that error detection always comes ... More
Parsing of Spoken Language under Time ConstraintsSep 09 1994Spoken language applications in natural dialogue settings place serious requirements on the choice of processing architecture. Especially under adverse phonetic and acoustic conditions parsing procedures have to be developed which do not only analyse ... More
Rules of Thumb for Information Acquisition from Large and Redundant DataDec 16 2010We develop an abstract model of information acquisition from redundant data. We assume a random sampling process from data which provide information with bias and are interested in the fraction of information we expect to learn as function of (i) the ... More
Comment on: I-Shih Liu: Constitutive theory of anisotropic rigid heat conductorsJun 15 2011In I-Shih Liu's paper \C{1}, the compatibility of anisotropy and material frame indifference of a rigid heat conductor is investigated. For this purpose, the deformation gradient is introduced into the domain of the constitutive mapping. Because of the ... More
Non-Equilibrium Thermodynamics and Stochasticity, A Phenomenological Look on Jarzynki's EqualityMar 07 2016The theory of phenomenological Non-equilibrium Thermodynamics is extended by includimg stochastic processes in order to account for recently derived thermodynamical relations such as the Jarzynski equality. Four phenomenological axioms are postulated ... More
Photons in a BallOct 15 2015Dec 16 2015The electromagnetic field inside a spherical cavity of large radius R is considered in the presence of stationary charge and current densities. R provides infra-red regularization while maintaining gauge invariance. The quantum ground state of physical ... More
Darwinian Adverse SelectionJul 14 2015We develop a model to study the role of rationality in economics and biology. The model's agents differ continuously in their ability to make rational choices. The agents' objective is to ensure their individual survival over time or, equivalently, to ... More
Flat bands and long range Coulomb interactions: conducting or insulating?Jul 23 2014Dispersionless (flat) electronic bands are investigated regarding their conductance properties. Due to "caging" of carriers these bands are usually insulating at partial filling, at least on the non-interacting level. Considering the specific example ... More
The initial value problem as it relates to numerical relativityOct 12 2016Spacetime is foliated by spatial hypersurfaces in the 3+1 split of General Relativity. The initial value problem then consists of specifying initial data for all relevant fields on one such a spatial hypersurface. These fields are the 3-metric and extrinsic ... More
The Linearization of Pairwise Markov NetworksFeb 17 2015Belief Propagation (BP) allows to approximate exact probabilistic inference in graphical models, such as Markov networks (also called Markov random fields, or undirected graphical models). However, no exact convergence guarantees for BP are known, in ... More
Semi-Supervised Learning with HeterophilyDec 09 2014We propose a novel linear semi-supervised learning formulation that is derived from a solid probabilistic framework: belief propagation. We show that our formulation generalizes a number of label propagation algorithms described in the literature by allowing ... More
New Physics Interpretations of the B-->K*mu+mu- AnomalyMay 20 2014This talk discusses possible new physics interpretations of recent experimental results on the B-->K*mu+mu- decay that show a discrepancy with the Standard Model predictions. A model independent analysis that takes into account all the relevant observables ... More
On the number of soft quanta in classical field configurationsJun 26 2013Aug 26 2013A crucial ingredient in the large-N quantum portrait of black holes proposed by Dvali and Gomez is the estimate of the number of soft quanta that make up the classical gravitational field. It is argued here that the coherent state formalism provides a ... More
Temperatures of Fragment Kinetic Energy SpectraNov 28 1994Nov 29 1994Multifragmentation reactions without large compression in the initial state (proton-induced reactions, reverse-kinematics, projectile fragmentation) are examined, and it is verified quantitatively that the high temperatures obtained from fragment kinetic ... More
Particle-particle correlations and the space-time structure of heavy ion collisionsFeb 26 1993The present status of the use of two-particle intensity interferometry as a diagnostic tool to study the space-time dynamics of intermediate energy heavy ion collisions is examined. Calculations for the two-proton and two-pion correlation functions are ... More
On Designs for Recursive Least Squares Residuals to Detect AlternativesJun 28 2016Linear regression models are checked by a lack-of-fit (LOF) test to be sure that the model is at least approximatively true. In many practical cases data are sampled sequentially. Such a situation appears in industrial production when goods are produced ... More
Janus-Facedness of the Pion: Analytic Instantaneous Bethe-Salpeter ModelsJul 08 2016Inversion enables the construction of interaction potentials underlying - under fortunate circumstances even analytic - instantaneous Bethe-Salpeter descriptions of all lightest pseudoscalar mesons as quark-antiquark bound states of Goldstone-boson nature. ... More
Adatom pair distribution up to half coverage: O-Pd(100)Dec 03 2017Aug 18 2018The superposition approximation allows to calculate from pair potentials pair distributions in thermal equilibrium with the Born-Green-Yvon (BGY) equation. A 2-d variant can be used to derive adatom pair distributions from arbitrary analytical pair potentials. ... More
Goldstone-Type Pseudoscalar Mesons: Instantaneous Bethe-Salpeter ModelsSep 06 2016A nontrivial instantaneous variant of the Bethe-Salpeter formalism allows us to discuss massless pseudoscalar mesons from a configuration-space-potential point of view.
Twisting $L^2$-invariants with finite-dimensional representationsSep 30 2015Mar 27 2017We investigate how one can twist L^2-invariants such as L^2-Betti numbers and L^2-torsion with finite-dimensional representations. As a special case we assign to the universal covering of a finite connected CW-complex X together with an element phi in ... More
Hawking radiation is corpuscularJun 06 2016Jun 29 2016The total number of Hawking quanta emitted during the evaporation of a Schwarzschild black hole is proportional to the square of the initial mass or, equivalently, to the Bekenstein entropy. This simple, but little appreciated, fact is interpreted in ... More
Andersen Filtration and Hard LefschetzApr 27 2006Jul 23 2007On the space of homomorphisms from a Verma module to an indecomposable tilting module of the BGG-category O we define a natural filtration following Andersen and establish a formula expressing the dimensions of the filtration steps in terms of coefficients ... More
The Hilbert Space Representations for SO_q(3)-symmetric quantum mechanicsApr 06 1994The observable algebra O of SO_q(3)-symmetric quantum mechanics is generated by the coordinates of momentum and position spaces (which are both isomorphic to the SO_q(3)-covariant real quantum space R_q^3). Their interrelations are determined with the ... More
Ladder operators for Klein-Gordon equation with scalar curvature termOct 03 2017Dec 20 2017Recently, Cardoso, Houri and Kimura constructed generalized ladder operators for massive Klein-Gordon scalar fields in space-times with conformal symmetry. Their construction requires a closed conformal Killing vector, which is also an eigenvector of ... More
New boundary variables for classical and quantum gravity on a null surfaceApr 24 2017The covariant Hamiltonian formulation for general relativity is studied in terms of self-dual variables on a manifold with an internal and lightlike boundary. At this inner boundary, new canonical variables appear: a spinor and a spinor-valued two-form ... More
New ISR Cross Section Results on KS KL pi0 and KS KL pi0 pi0 From BABARNov 25 2016We present preliminary measurements of the cross sections for e+e- --> KS KL pi0 and KS KL pi0 pi0 obtained using the technique of Initial State Radiation with 469 fb^-1 of e+e- collision data collected with the BABAR detector at or near the Upsilon(4S) ... More
On Matrix Factorizations, Residue Pairings and Homological Mirror SymmetryMar 27 2018Apr 11 2018We argue how boundary B-type Landau-Ginzburg models based on matrix factorizations can be used to compute exact superpotentials for intersecting D-brane configurations on compact Calabi-Yau spaces. In this paper, we consider the dependence of open-string, ... More
Generating functional for gravitational null initial dataMay 15 2019A field theory on a three-dimensional manifold is introduced, whose field equations are the constraint equations for general relativity on a three-dimensional null hypersurface. The underlying boundary action consists of two copies of the dressed Chern-Simons ... More
Quantum Approximate Optimization with Parallelizable GatesFeb 04 2018Mar 01 2018The quantum approximate optimization algorithm (QAOA) has been introduced as a heuristic digital quantum computing scheme to find approximate solutions of combinatorial problems with shallow circuits. We present a scheme to parallelize this approach for ... More
Fluxon-induced losses in niobium thin-film cavities revisitedApr 15 2019Long standing data from niobium thin film accelerating cavities will be revisited and analyzed by the two-fluid model of RF superconductivity. Firstly, the applicability and limitation of this model are explored using data of the BCS surface resistance ... More
First-principles lattice-gas Hamiltonian revisited: O-Pd(100)Oct 28 2016Nov 30 2017The methodology of deriving an adatom lattice-gas Hamiltonian (LGH) from first principles (FP) calculations is revisited. Such LGH cluster expansions compute a large set of lateral pair-, trio-, quarto interactions by solving a set of linear equations ... More
The initial value problem as it relates to numerical relativityOct 12 2016Dec 23 2016Spacetime is foliated by spatial hypersurfaces in the 3+1 split of General Relativity. The initial value problem then consists of specifying initial data for all relevant fields on one such a spatial hypersurface. These fields are the 3-metric and extrinsic ... More
The Burnside Ring and Equivariant Stable Cohomotopy for Infinite GroupsApr 04 2005Jul 12 2005After we have given a survey on the Burnside ring of a finite group, we discuss and analyze various extensions of this notion to infinite (discrete) groups. The first three are the finite-G-set-version, the inverse-limit-version and the covariant Burnside ... More
The Segal Conjecture for Infinite GroupsJan 26 2019We formulate and prove a version of the Segal Conjecture for infinite groups. For finite groups it reduces to the original version. The condition that G is finite is replaced in our setting by the assumption that there exists a finite model for the classifying ... More
Lattice QCD with 2+1 Flavors and Open Boundaries: First Results of the Baryon SpectrumFeb 19 2015Feb 26 2015Based on CLS simulations with 2+1 flavors and open boundaries we present first results of the baryon spectrum. We report on the status of our effort related to these simulations and the chiral extrapolation to the physical point.
Difference Problems and Differential ProblemsDec 03 2007We state some elementary problems concerning the relation between difference calculus and differential calculus, and we try to convince the reader that, in spite of the simplicity of the statements, a solution of these problems would be a significant ... More
Comment on the paper: Quantum backaction of optical observations on Bose-Einstein condensates by U. Leonhardt, T. Kiss, and P. Piwnicki, Eur. Phys. J. D7, 413 (1999)Jun 27 2000A recent paper, Quantum backaction of optical observations on Bose-Einstein condensates by U. Leonhardt, T. Kiss, and P. Piwnicki, Eur. Phys. J. D7, 413 (1999), emphasized that the limit of dispersive imaging of Bose-Einstein condensates with off-resonant ... More
Presentations of symbolic dynamical systems by labelled directed graphs (Notes for a "mini-cours", SDA2, Paris 4-5 October 2007)Sep 10 2012We develop some aspects of a general theory of presentations of subshifts by labelled directed graphs, in particular by compact graphs. Also considered are synchronization properties of subshifts that lead to presentations by countable graphs.
On $g$-functions for subshiftsAug 10 2006A necessary and sufficient condition is given for a subshift presentation to have a continuous $g$-function. An invariant necessary and sufficient condition is formulated for a subshift to posses a presentation that has a continuous $g$-function.
On a Fair Copy of Riemann's 1859 Publication Created by Alfred ClebschDec 09 2015Dec 16 2015We will verify that the fair copy "Ueber die Anzahl der Primzahlen unter einer gegebenen Gr\"osse" found in Riemann's Nachlass is not in Riemann's hand. Further, we will show that this paper was written by Alfred Clebsch and that it was used after Clebsch's ... More
Bivariate Lagrange interpolation at the node points of Lissajous curves - the degenerate caseMar 03 2015Apr 03 2016In this article, we study bivariate polynomial interpolation on the node points of degenerate Lissajous figures. These node points form Chebyshev lattices of rank $1$ and are generalizations of the well-known Padua points. We show that these node points ... More
Assembly MapsMay 01 2018Jan 02 2019We introduce and analyze the concept of an assembly map from the original homotopy theoretic point of view. We give also interpretations in terms of surgery theory, controlled topology and index theory. The motivation is that prominent conjectures of ... More
Tables of prehomogeneous modules and étale modules of reductive algebraic groupsOct 22 2016This document contains tables with the classification of prehomogeneous modules for reductive algebraic groups with up to two simple factors due to Sato, Kimura and many others, as well as corresponding tables of the \'etale modules appearing in this ... More
Asymptotic optimality of scalar Gersho quantizersMar 16 2012Jun 21 2013In his famous paper [7] Gersho stressed that the codecells of optimal quantizers asymptotically make an equal contribution to the distortion of the quantizer. Motivated by this fact, we investigate in this paper quantizers in the scalar case, where each ... More
Accelerated Landweber methods based on co-dilated orthogonal polynomialsJun 09 2012Dec 20 2012In this article, we introduce and study accelerated Landweber methods for linear ill-posed problems obtained by an alteration of the coefficients in the three-term recurrence relation of the \nu-methods. The residual polynomials of the semi-iterative ... More
On the geometry of cohomogeneity one manifolds with positive curvatureJul 23 2007This is a survey on cohomogeneity one manifolds with positive curvature. We discuss the known examples of this type and their geometry and the functions that describe the metric. We also describe the classification of cohomogeneity one manifolds that ... More
K- and L-theory of the semi-direct product of the discrete 3-dimensional Heisenberg group by Z/4Dec 08 2004Sep 11 2005We compute the group homology, the topological K-theory of the reduced C^*-algebra, the algebraic K-theory and the algebraic L-theory of the group ring of the semi-direct product of the three-dimensional discrete Heisenberg group by Z/4. These computations ... More
Survey on geometric group theoryJun 23 2008Sep 11 2008This article is a survey article on geometric group theory from the point of view of a non-expert who likes geometric group theory and uses it in his own research. The sections are: classical examples, basics about quasiisometry,properties and invariants ... More
L^2-Invariants from the Algebraic Point of ViewOct 31 2003We give a survey on L^2-invariants such as L^2-Betti numbers and L^2-torsion taking an algebraic point of view. We discuss their basic definitions, properties and applications to problems arising in topology, geometry, group theory and K-theory.
Holonomy Groups of Complete Flat Pseudo-Riemannian Homogeneous SpacesMay 15 2012Aug 13 2012We show that a complete flat pseudo-Riemannian homogeneous manifold with non-abelian linear holonomy is of dimension at least 14. Due to an example constructed in a previous article by Oliver Baues and the author, this is a sharp bound. Also, we give ... More
The Poincaré series of some special quasihomogeneous surface singularitiesApr 13 2000Sep 26 2001In the author's paper ''Poincar\'{e} series and monodromy of a two-dimensional quasihomogeneous hypersurface singularity'' a relation is proved between the Poincar\'{e} series of the coordinate algebra of a two-dimensional quasihomogeneous isolated hypersurface ... More
Shadows of graphical mean curvature flowApr 18 2016We consider mean curvature flow of an initial surface that is the graph of a function over some domain of definition in $R^n$. If the graph is not complete then we impose a constant Dirichlet boundary condition at the boundary of the surface. We establish ... More
Searching for New Physics with Flavor Violating ObservablesJun 04 2012In this talk, I review the status and prospects of several low energy flavor observables that are highly sensitive to New Physics effects. In particular I discuss the implications for possible New Physics in b --> s transitions coming from the recent ... More
Top Quark Cross-Section Measurements at the TevatronDec 02 2003Run II of the Tevatron collider at Fermilab is well under way and data samples larger than those of Run I are at hand. In this contribution I summarize the current status of cross-section measurements for top-quark pair production at the CDF and D0 experiments. ... More
A new numerical method to construct binary neutron star initial dataAug 05 2009We present a new numerical method for the generation of binary neutron star initial data using a method along the lines of the the Wilson-Mathews or the closely related conformal thin sandwich approach. Our method uses six different computational domains, ... More
Constructing quasi-equilibrium initial data for binary neutron stars with arbitrary spinsSep 24 2012Nov 04 2014In general neutron stars in binaries are spinning. Recently, a new quasi-equilibrium approximation that includes a rotational velocity piece for each star has been proposed to describe binary neutron stars with arbitrary rotation states in quasi-circular ... More
Comment on the paper "Electromagnetic Wave Dynamics in Matter-Wave Superradiant Scattering" by L. Deng, M.G. Payne, and E.W. HagleyOct 19 2010The paper by Deng et al. (Phys. Rev. Lett. 104, 050402 (2010)) presents an analytic theoretical description of matter-wave superradiance (Phys. Rev. Lett. 85, 4225-4228 (2000)) which claims to go beyond previous theoretical frameworks. I show here that ... More
Chiral gauge theories on the lattice without gauge fixing?Nov 30 1993We discuss two proposals for a non-perturbative formulation of chiral gauge theories on the lattice. In both cases gauge symmetry is broken by the regularization. We aim at a dynamical restoration of symmetry. If the gauge symmetry breaking is not too ... More
Limiting soft particle production and QCDNov 10 2010We present some basic elements of the treatment of particle multiplicities in jets from high energy collisions within perturbative QCD. Then we discuss the universal features of the inclusive particle spectrum for the limiting case of momentum p\to 0 ... More
Scaling and scale breaking phenomena in QCD jetsNov 12 1996The perturbative QCD approach to multiparticle production assuming Local Parton Hadron Duality (LPHD) and some recent results are discussed. Finite asymptotic scaling limits are obtained for various observables, after an appropriate rescaling, in the ... More
UNIVERSAL PROPERTIES OF ANGULAR CORRELATIONS IN QCD JETSJan 16 1995Predictions for angular correlations between an arbitrary number of partons are derived in the high energy limit. The quantities considered depend on angles and primary energy through a single variable $\epsilon$ which implies certain scaling properties ... More