Results for "Stephan Diehl"

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Usage and Attribution of Stack Overflow Code Snippets in GitHub ProjectsFeb 08 2018Stack Overflow (SO) is the largest Q&A website for software developers, providing a huge amount of copyable code snippets. Using those snippets raises maintenance and legal issues. SO's license (CC BY-SA 3.0) requires attribution, i.e., referencing the ... More
Measuring 26Al and 60Fe in the GalaxyMar 24 2006With the SPI high-resolution spectrometer on INTEGRAL, new results have been obtained for long-lived radioactive 26Al and 60Fe in our Galaxy: 26Al sources apparently share the pattern of Galactic rotation in the inner Galaxy, and thus allow to estimate ... More
Measuring Cosmic Elements with Gamma-Ray TelescopesJul 31 2009Gamma-ray telescopes are capable of measuring radioactive trace isotopes from cosmic nucleosynthesis events. Such measurements address new isotope production rather directly for a few key isotopes such as 44Ti, 26Al, 60Fe, and 56Ni, as well as positrons ... More
Particle Acceleration in Cosmic Sites - Astrophysics Issues in our Understanding of Cosmic RaysFeb 27 2009Jun 10 2009Laboratory experiments to explore plasma conditions and stimulated particle acceleration can illuminate aspects of the cosmic particle acceleration process. Here we discuss the cosmic-ray candidate source object variety, and what has been learned about ... More
Multiple interactions and generalized parton distributionsJul 30 2010Multiple parton interactions in a single proton-proton collision are expected to play an important role for many observables at LHC. To a large part their phenomenological description relies on rather simple and physically intuitive assumptions. We report ... More
Some news about generalised parton distributionsAug 07 2008I briefly discuss some recent developments (and recall some old news) in the theory and phenomenology of generalised parton distributions.
Generalized parton distributions: recent resultsDec 15 2005I review progress on selected issues connected with generalized parton distributions. Topics range from the description of hard exclusive reactions to the spatial distribution of quarks in the nucleon and the contribution of their orbital angular momentum ... More
Exploring skewed parton distribution with polarized targetOct 18 2000I briefly review the physics of skewed parton distributions. Special emphasis is put on the relevance of target polarization, and on the different roles of small and of intermediate x_B.
Generalized parton distributions with helicity flipJan 30 2001We show that for both quarks and gluons there are eight generalized parton distributions in the proton: four which conserve parton helicity and four which do not. We explain why time reversal invariance does not reduce this number from eight to six, as ... More
Photon polarisation in diffractive deep inelastic scatteringSep 15 1997The distribution of a suitably defined azimuthal angle in diffractive deep inelastic scattering contains information on the polarisation of the exchanged photon. In particular it allows one to constrain the longitudinal diffractive structure function. ... More
Universality in the BCS - BEC Crossover in Cold Fermion GasesJan 08 2007We address the finite temperature phase diagram of ultracold fermionic atoms across a Feshbach resonance based on a functional integral for an atom-molecule model. This allows to fully exploit the presence of the global symmetry of phase rotations, U(1). ... More
Non-Equilibrium Universality in the Heating Dynamics of Interacting Luttinger LiquidsApr 14 2014Jun 02 2016We establish a new non-equilibrium scaling regime in the short time evolution of one-dimensional interacting open quantum systems subject to a generic heating mechanism. This dynamical regime is characterized by uncompensated phonon production and a super-diffusive, ... More
Driven Markovian Quantum CriticalityAug 11 2015Feb 18 2016We identify a new universality class in one-dimensional driven open quantum systems with a dark state. Salient features are the persistence of both the microscopic non-equilibrium conditions as well as the quantum coherence of dynamics close to criticality. ... More
Functional Integral for Ultracold Fermionic AtomsOct 15 2005Feb 07 2007We develop a functional integral formalism for ultracold gases of fermionic atoms. It describes the BEC - BCS crossover and involves both atom and molecule fields. Beyond mean field theory we include the fluctuations of the molecule field by the solution ... More
Some numerical studies of the evolution of generalized parton distributionsNov 14 2007Jan 08 2008We study the evolution behavior of generalized parton distributions at small longitudinal momentum fraction. Particular attention is paid to the ratio of a generalized parton distribution and its forward limit, to the mixing between quarks and gluons, ... More
Diffraction for non-believersNov 04 2005Diffractive reactions involving a hard scale can be understood in terms of quarks and gluons. These reactions have become a valuable tool for investigating the low-x structure of the proton and the behavior of QCD in the high-density regime, and they ... More
Kinetic Theory for Interacting Luttinger LiquidsJan 05 2015Oct 06 2015We derive a closed set of equations for the kinetics and non-equilibrium dynamics of interacting Luttinger Liquids with cubic resonant interactions. In the presence of these interactions, the Luttinger phonons become dressed but still well defined quasi-particles, ... More
Beyond the Rosenfeld Functional: Loop Contributions in Fundamental Measure TheoryAug 20 2012The Rosenfeld functional provides excellent results for the prediction of the fluid phase of hard convex particle systems but fails beyond the freezing point. The reason for this limitation is the neglect of orientational and distance correlations beyond ... More
Deriving the Rosenfeld Functional from the Virial ExpansionNov 22 2011Apr 19 2012In this article we replace the semi-heuristic derivation of the Rosenfeld functional of hard convex particles with the systematic calculation of Mayer clusters. It is shown that each cluster integral further decomposes into diagrams of intersection patterns ... More
An Operational Petri Net Semantics for the Join-CalculusAug 14 2012We present a concurrent operational Petri net semantics for the join-calculus, a process calculus for specifying concurrent and distributed systems. There often is a gap between system specifications and the actual implementations caused by synchrony ... More
Asymptotics of generalised trinomial coefficientsMay 24 2012Jul 01 2012It is shown how to obtain an asymptotic expansion of the generalised central trinomial coefficient $[x^n](x^2 + bx + c)^n$ by means of singularity analysis, thus proving a conjecture of Zhi-Wei Sun.
Hyperboloid preservation implies the Lorentz and Poincaré groups without dilationsSep 20 2010An analogue of the Alexandrov-Zeeman theorem, based on hyperboloid preservation, as opposed to light cone preservation, is provided. This characterizes exactly the Poincar\'e group, as opposed to the Poincar\'e group extended by dilations. The hyperbolic ... More
Wetting on Random Roughness: the Ubiquity of Wenzel PrewettingMar 23 2012The wetting properties of solid substrates with macroscopic random roughness are considered as a function of the microscopic contact angle of the wetting liquid and its partial pressure in the surrounding gas phase. It is shown that Wenzel prewetting, ... More
Normal surfaces in topologically finite 3-manifoldsJun 14 2004Jun 12 2007The concept of a normal surface in a triangulated, compact 3-manifold was generalised by Thurston to a spun-normal surface in a non-compact 3-manifold with ideal triangulation. This paper defines a boundary curve map which takes a spun-normal surface ... More
The square sieve and the large sieve with square moduliJun 19 2015Jun 07 2016We give a short alternative proof using Heath-Brown's square sieve of a bound of the author for the large sieve with square moduli.
Exponential sums with coefficients of certain Dirichlet seriesAug 12 2011Sep 12 2011Under the generalized Lindel\"of Hypothesis in the t- and q-aspects, we bound exponential sums with coefficients of Dirichlet series belonging to a certain class. We use these estimates to establish a conditional result on squares of Hecke eigenvalues ... More
Exponential sums with Dirichlet coefficients of L-functionsJun 22 2012Oct 29 2012Improving and extending recent results of the author, we conditionally estimate exponential sums with Dirichlet coefficients of L-functions, both over all integers and over all primes in an interval. In particular, we establish new conditional results ... More
An extension of disjunctive programming and its impact for compact tree formulationsJul 07 2010In the 1970's, Balas introduced the concept of disjunctive programming, which is optimization over unions of polyhedra. One main result of his theory is that, given linear descriptions for each of the polyhedra to be taken in the union, one can easily ... More
Diophantine approximation on lines in $\mathbb{C}^2$ with Gaussian prime constraintsDec 08 2016We study the problem of Diophantine approximation on lines in $\mathbb{C}^2$ with numerators and denominators restricted to Gaussian primes.
Note on antichain cutsets in discrete semimodular latticesFeb 26 2011The characterization of level sets of finite Boolean lattices as antichain cutsets, due to Rival and Zaguia, is seen to hold in all discrete semimodular lattices.
Generalization of Conway's "Game of Life" to a continuous domain - SmoothLifeNov 07 2011Dec 07 2011We present what we argue is the generic generalization of Conway's "Game of Life" to a continuous domain. We describe the theoretical model and the explicit implementation on a computer.
Generalized Dicke StatesJan 09 2012Sep 06 2016Quantum master equations are an important tool in quantum optics and quantum information theory. For systems comprising a small to medium number of atoms (or qubits), the non-truncated equations are usually solved numerically. In this paper, we present ... More
Boundary slopes and the logarithmic limit setJun 03 2003The A-polynomial of a manifold whose boundary consists of a single torus is generalised to an eigenvalue variety of a manifold whose boundary consists of a finite number of tori, and the set of strongly detected boundary curves is determined by Bergman's ... More
Quantum interferences in quasicrystalsJul 30 1999Jul 31 1999Contributions of quantum interference effects occuring in quasicrystals are emphasized. First conversely to metallic systems, quasiperiodic ones are shown to enclose original alterations of their conductive properties while downgrading long range order. ... More
Labeled trees, maps, and an algebraic identityJun 16 2011Jun 23 2011We give a short and direct proof of a remarkable identity that arises in the enumeration of labeled trees with respect to their indegree sequence, where all edges are oriented from the vertex with lower label towards the vertex with higher label. This ... More
A Short Counterexample to the Inverse Generator Problem on non-Hilbertian Reflexive $L^p$-spacesApr 08 2016We show that the bilateral shift group on $L^p(\mathbb{R})$ for $p \in (1, \infty) \setminus \{2\}$ provides a counterexample to the inverse generator problem.
Search for Higgs and New Phenomena at CollidersJan 20 2006The present status of searches for the Higgs boson(s) and new phenomena is reviewed. The focus is on analyses and results from the current runs of the HERA and Tevatron experiments. The LEP experiments have released their final combined MSSM Higgs results ... More
Lattice-Fluid Models derived from Density Functional TheoryMar 08 2015In the current article, we rederive the lattice-fluid excess models UNIQUAC, UNIFAC, and COSMO-RS from a continuum functional. The calculation explains the missing dependence on the particle geometry and how to include the Coulomb interaction, problems ... More
The Kraft sum as a monotone function on the refinement-ordered set of uniquely decipherable codesMay 17 2013Jun 27 2013The set of all uniquely decipherable (UD) codes is partially ordered by refinement, meaning that all strings in the cruder code can be represented as concatenations of strings taken from the finer code. The Kraft sum is a monotone (increasing) function ... More
A Two Stage CVT / Eikonal Convection Mesh Deformation Approach for Large Nodal DeformationsNov 27 2014A two step mesh deformation approach for large nodal deformations, typically arising from non-parametric shape optimization, fluid-structure interaction or computer graphics, is considered. Two major difficulties, collapsed cells and an undesirable parameterization, ... More
Damping of Bloch oscillations: Variational solutions of the Boltzmann equation beyond linear responseSep 01 2014Nov 20 2014Variational solutions of the Boltzmann equation usually rely on the concept of linear response. We extend the variational approach for tight-binding models at high entropies to a regime far beyond linear response. We analyze both weakly interacting fermions ... More
Application of Methods for Syntax Analysis of Context-Free Languages to Query Evaluation of Logic ProgramsMay 15 2014My research goal is to employ a parser generation algorithm based on the Earley parsing algorithm to the evaluation and compilation of queries to logic programs, especially to deductive databases. By means of partial deduction, from a query to a logic ... More
Density Functional Theory for Hard Particles in N DimensionsMar 09 2014Recently it has been shown that the heuristic Rosenfeld functional derives from the virial expansion for particles which overlap in one center. Here, we generalize this approach to any number of intersections. Starting from the virial expansion in Ree-Hoover ... More
An obstruction to the smoothability of singular nonpositively curved metrics on 4-manifolds by patterns of incompressible toriDec 08 2013Aug 11 2015We give new examples of closed smooth 4-manifolds which support singular metrics of nonpositive curvature, but no smooth ones, thereby answering affirmatively a question of Gromov. The obstruction comes from patterns of incompressible 2-tori sufficiently ... More
Continuity of the Maximum-Entropy InferenceFeb 14 2012Apr 21 2014We study the inverse problem of inferring the state of a finite-level quantum system from expected values of a fixed set of observables, by maximizing a continuous ranking function. We have proved earlier that the maximum-entropy inference can be a discontinuous ... More
Standard bases with respect to the Newton filtrationApr 15 1999The aim of this article is to introduce standard bases of ideals in polynomial rings with respect to a class of orderings which are not necessarily semigroup orderings. Our approach generalises the concept of standard bases with respect to semigroup orderings ... More
On a topological fractional Helly theoremJun 20 2005We prove a new fractional Helly theorem for families of sets obeying topological conditions. More precisely, we show that the nerve of a finite family of open sets (and of subcomplexes of cell complexes) in R^d is k-Leray where k depends on the dimension ... More
Convergence issues in ChPT: a lattice perspectiveMay 24 2013This review addresses the practical convergence of the ChPT series in the p-regime. In the SU(2) framework there is a number of new results, and improved estimates of \bar\ell_3 and \bar\ell_4 are available. In the SU(3) framework few new lattice computations ... More
Logarithmic link smearing for full QCDSep 26 2007Mar 16 2009A Lie-algebra based recipe for smoothing gauge links in lattice field theory is presented, building on the matrix logarithm. With or without hypercubic nesting, this LOG/HYL smearing yields fat links which are differentiable w.r.t. the original ones. ... More
The phase transition in the multiflavour Schwinger modelSep 12 2000A summary is given of a quantization of the multiflavour Schwinger model on a finite-temperature cylinder with chirality-breaking boundary conditions at its spatial ends, and it is shown that the analytic expression for the chiral condensate implies that ... More
QCD in a finite box: Numerical test studies in the three Leutwyler-Smilga regimesAug 30 2000Nov 07 2000The Leutwyler-Smilga prediction regarding the (ir)relevance of the global topological charge for QCD in a finite box is subject to a test. To this end the lattice version of a suitably chosen analogue (massive 2-flavour Schwinger model) is analyzed in ... More
The spectrum of light isovector mesons with $C=+1$ from the COMPASS experimentOct 04 2016Based on the largest event sample of diffractively produced $\pi^-\pi^-\pi^+$, obtained by a pion beam of $190~\rm{GeV/c}$ momentum, the COMPASS collaboration has performed the most advanced partial wave analysis on multi-body final states, using the ... More
Non-Autonomous Maximal $L^p$-Regularity under Fractional Sobolev Regularity in TimeNov 28 2016We prove non-autonomous maximal $L^p$-regularity results on UMD spaces replacing the common H\"older assumption by a weaker fractional Sobolev regularity in time. This generalizes recent Hilbert space results by Dier and Zacher. In particular, on $L^q(\Omega)$ ... More
Minimal even sets of nodesOct 20 1997We extend some results on even sets of nodes which have been proved for surfaces up to degree 6 to surfaces up to degree 10. In particular, we give a formula for the minimal cardinality of a nonempty even set of nodes.
A Projective Surface of Degree Eight with 168 NodesJul 19 1995The estimate for the maximal number of ordinary double points of a projective surface of degree eight is improved to $168\leq\mu(8)\leq 174$ by constructing a projective surface of degree eight with 168 nodes.
Degenerations of ideal hyperbolic triangulationsAug 16 2005Jun 07 2011Let M be a cusped 3-manifold, and let T be an ideal triangulation of M. The deformation variety D(T), a subset of which parameterises (incomplete) hyperbolic structures obtained on M using T, is defined and compactified by adding certain projective classes ... More
On the divisor class group of double solidsSep 28 1998Sep 29 1998For a double solid $V\to P_3(C)$ branched over a surface $B\subset P_3(C)$ with only ordinary nodes as singularities, we give a set of generators of the divisor class group $Pic(\tilde{V}})$ in terms of contact surfaces of $B$ with only superisolated ... More
A Proposal for the Measurement and Documentation of Research Software Sustainability in Interactive Metadata RepositoriesAug 16 2016Aug 17 2016This paper proposes an interactive repository type for research software metadata which measures and documents software sustainability by accumulating metadata, and computing sustainability metrics over them. Such a repository would help to overcome technical ... More
Dark matter constraints on the parameter space and particle spectra in the nonminimal SUSY standard modelApr 04 1997Aug 19 1997We investigate the dark matter constraints for the nonminimal SUSY standard model (NMSSM). The cosmologically restricted mass spectra of the NMSSM are compared to the minimal SUSY standard model (MSSM). The differences of the two models concerning the ... More
Distribution Functionals for Hard Particles in N DimensionsFeb 15 2015The current article completes our investigation of the hard-particle interaction by determining their distribution functionals. Beginning with a short review of the perturbation expansion of the free-energy functional, we derive two representations of ... More
The MaxEnt extension of a quantum Gibbs family, convex geometry and geodesicsOct 31 2014We discuss methods to analyze a quantum Gibbs family in the ultra-cold regime where the norm closure of the Gibbs family fails due to discontinuities of the maximum-entropy inference. The current discussion of maximum-entropy inference and irreducible ... More
Discontinuities in the Maximum-Entropy InferenceAug 28 2013We revisit the maximum-entropy inference of the state of a finite-level quantum system under linear constraints. The constraints are specified by the expected values of a set of fixed observables. We point out the existence of discontinuities in this ... More
The number of fixed points of Wilf's partition involutionJul 24 2013Wilf partitions are partitions of an integer $n$ in which all nonzero multiplicities are distinct. On his webpage, the late Herbert Wilf posed the problem to find "any interesting theorems" about the number f(n) of those partitions. Recently, Fill, Janson ... More
On the structure of semigroups on $L_p$ with a bounded $H{^\infty}$-calculusOct 17 2013Oct 07 2014We show that a bounded analytic semigroup on an $L_p$-space has a bounded $H^{\infty}(\Sigma_{\varphi})$-calculus for some $\varphi < \frac{\pi}{2}$ if and only if the semigroup can be obtained, after restricting to invariant subspaces, factorizing through ... More
On distances and metrics in discrete ordered setsJun 30 2013Discrete partially ordered sets can be turned into distance spaces in several ways. The distance functions may or may not satisfy the triangle inequality, and restriction of the distance to finite chains may or may not coincide with the natural, difference-of-height ... More
Feasibility of giant fiber-optic gyroscopesJan 04 2013Mar 07 2013The availability of long-distance, underground fiber-optic links opens a perspective of implementing interferometric fiber-optic gyroscopes embracing very large areas. We discuss the potential sensitivity, some disturbances and approaches to overcome ... More
Towards a characterization of Markov processes enjoying the time-inversion propertyJun 01 2005Apr 26 2007We give a necessary and sufficient condition for a homogeneous Markov process taking values in $\R^n$ to enjoy the time-inversion property of degree $\alpha$. The condition sets the shape for the semigroup densities of the process and allows to further ... More
Introduction to Physical Implementations of Quantum Information ProcessingMar 01 2013This was a contribution to the lecture notes on the 44th IFF Spring School held at Forschungszentrum J\"ulich in 2013 on "Quantum Information Processing". The school as a whole had a strong focus on solid state systems. It was the purpose of this contribution ... More
Recent Progress in Lattice QCDJan 09 2013Recent progress in Lattice QCD is highlighted. After a brief introduction to the methodology of lattice computations the presentation focuses on three main topics: Hadron Spectroscopy, Hadron Structure and Lattice Flavor Physics. In each case a summary ... More
Gauge action improvement and smearingSep 23 2004Dec 28 2005The effect of repeatedly smearing SU(3) gauge configurations is investigated. Six gauge actions (Wilson, Symanzik, Iwasaki, DBW2, Beinlich-Karsch-Laermann, Langfeld; combined with a direct SU(3)-overrelaxation step) and three smearings (APE, HYP, EXP) ... More
Aspects of Quasi-Phasestructure of the Schwinger Model on a Cylinder with Broken Chiral SymmetryMay 19 1998Oct 05 1998We consider the N_f-flavour Schwinger Model on a thermal cylinder of circumference $\beta=1/T$ and of finite spatial length $L$. On the boundaries $x^1=0$ and $x^1=L$ the fields are subject to an element of a one-dimensional class of bag-inspired boundary ... More
Interfacing Constraint-Based Grammars and Generation AlgorithmsAug 07 2000Constraint-based grammars can, in principle, serve as the major linguistic knowledge source for both parsing and generation. Surface generation starts from input semantics representations that may vary across grammars. For many declarative grammars, the ... More
Algorithmic Meta-TheoremsFeb 20 2009Algorithmic meta-theorems are general algorithmic results applying to a whole range of problems, rather than just to a single problem alone. They often have a "logical" and a "structural" component, that is they are results of the form: every computational ... More
Singular moduli of higher level and special cyclesMay 11 2015Jun 25 2015We describe the complex multiplication (CM) values of modular functions for $\Gamma_0(N)$ whose divisor is given by a linear combination of Heegner divisors in terms of special cycles on the stack of CM elliptic curves. In particular, our results apply ... More
A Note on Touching Cones and FacesOct 14 2010May 03 2011We study touching cones of a (not necessarily closed) convex set in a finitedimensional real Euclidean vector space and we draw relationships to other concepts in Convex Geometry. Exposed faces correspond to normal cones by an antitone lattice isomorphism. ... More
Operator systems and convex sets with many normal conesJun 13 2016Sep 13 2016The state space of an operator system of $n$-by-$n$ matrices has, in a sense, many normal cones. Merely this convex geometrical property implies smoothness qualities and a clustering property of exposed faces. The latter holds since each exposed face ... More
Convergence of tree-valued Cannings chainsAug 29 2016We consider sequences of tree-valued Markov chains that describe evolving genealogies in Cannings models, and we show their convergence in distribution to tree-valued Fleming-Viot processes. Under the conditions of M\"ohle and Sagitov, this convergence ... More
Phase Transition in the Number Partitioning ProblemJul 06 1998Sep 21 1998Number partitioning is an NP-complete problem of combinatorial optimization. A statistical mechanics analysis reveals the existence of a phase transition that separates the easy from the hard to solve instances and that reflects the pseudo-polynomiality ... More
Status of the B^0_{(s)}-\bar B^0_{(s)}} mixing from QCD spectral sum RulesMar 18 2002In this talk, I present new results [1] obtained from QCD spectral sum rules (QSSR), on the bag constant parameters entering in the analysis of the B^0_{(s)}-\bar B^0_{(s)} mass-differences. Taking the average of the results from the Laplace and moment ... More
Light and heavy quark masses, Flavour breaking of chiral condensates, Meson weak leptonic decay constants in QCDFeb 21 2002We review the present status for the determinations of the light and heavy quark masses, the light quark chiral condensate and the decay constants of light and heavy-light (pseudo)scalar mesons from QCD spectral sum rules (QSSR). Bounds on the light quark ... More
A new perspective on the Holstein polaron problemJun 12 1996The single-polaron band structure of the Holstein model in one and two dimensions is studied using a new form of resummed strong-coupling perturbation theory. Well converged results are obtained for phonon frequencies of the order of the hopping integral ... More
On the meaning of mean shapeFeb 03 2010May 12 2011Various concepts of mean shape previously unrelated in the literature are brought into relation. In particular for non-manifolds such as Kendall's 3D shape space, this paper answers the question, for which means one may apply a two-sample test. The answer ... More
A note on inhomogeneous foliations with sectionsOct 03 2013We give an easy example showing that sections of a singular Riemannian foliation on a simply connected space neither have to be isometric nor injectively immersed.
Test of Symmetries with Neutrons and NucleiFeb 10 2009Mar 06 2009Precision experiments at low energies probing weak interaction are a very promising and complementary tool for investigating the structure of the electro-weak sector of the standard model, and for searching for new phenomena revealing signs for an underlaying ... More
A primer on A-infinity-algebras and their Hochschild homologyJan 15 2016We present an elementary and self-contained construction of $A_\infty$-algebras, $A_\infty$-bimodules and their Hochschild homology and cohomology groups. In addition, we discuss the cup product in Hochschild cohomology and the spectral sequence of the ... More
Transversity Distribution Does Not Contribute to Hard Exclusive Electroproduction of MesonsJul 26 1999We show that in hard exclusive electroproduction, ep-->eVp, the leading-twist hard-scattering coefficient for the production of a transversely polarized vector meson V vanishes to all orders of perturbation theory. This implies that this process cannot ... More
A representation for exchangeable coalescent trees and generalized tree-valued Fleming-Viot processesAug 29 2016We show that every exchangeable random semi-ultrametric on the integers can be obtained by sampling an iid sequence from a random marked metric measure space and adding the marks to the distances. We use this representation to define tree-valued Fleming-Viot ... More
Anomalous electronic conductance in quasicrystalsJul 27 1999Jul 31 1999Generic quantum interference effects occuring in 1D-quasicrystals are reviewed with emphasis on the joint effect of phason disorder on electronic localization and propagation modes. In close conjunction with properties of real materials, the contributions ... More
On McMillan's theorem about uniquely decipherable codesJun 19 2008Jun 21 2008Karush's proof of McMillan's theorem is recast as an argument involving polynomials with non-commuting indeterminates certain evaluations of which yield the Kraft sums of codes, proving a strengthened version of McMillan's theorem.
The Lorentz group and its finite field analogues: local isomorphism and approximationMay 08 2008Aug 04 2008Finite Lorentz groups acting on 4-dimensional vector spaces coordinatized by finite fields with a prime number of elements are represented as homomorphic images of countable, rational subgroups of the Lorentz group acting on real 4-dimensional space-time. ... More
Tackling master equations with a flux loop transformOct 25 2007Feb 21 2008A procedure is introduced which allows to represent the dynamics of a non-equilibrium system violating detailed balance by its steady state loop fluxes. It is shown that detailed balance is restored in this representation, such that the non-equilibrium ... More
Revisiting f_B and m_b(m_b) from HQET spectral sum rulesDec 21 2012Mar 14 2013Using recent values of the QCD (non-) perturbative parameters given in Table 1, we reconsider the extraction of f_B and the on-shell mass M_b from HQET Laplace spectral sum rules known to N2LO PT series and including dimension 7 condensates in the OPE. ... More
A Steinberg Cross-Section for Non-Connected Affine Kac-Moody GroupsJan 16 2004We generalise the concept of a Steinberg cross-section to non-connected Kac-Moody group. As in the connected case, which was treated by G. Br\"uchert, a quotient map w.r.t the conjugacy action exists only on a certain submonoid of the Kac-Moody group. ... More
A Remark on the Conjectures of Lang-Trotter and Sato-Tate on AverageAug 19 2007Aug 21 2007We obtain new average results on the conjectures of Lang-Trotter and Sato-Tate about elliptic curves.
The Neutron and the Universe - History of a RelationshipMay 11 2012We discuss selected topics in the field of particle- and astrophysics with neutrons. They have a direct link with our understanding of the history of the Universe and are related to recent, ongoing or future measurements. They deal with the structure ... More
The Puzzle of Neutron LifetimeFeb 01 2009Mar 06 2009In this paper we review the role of the neutron lifetime and discuss the present status of measurements. In view of the large discrepancy observed by the two most precise individual measurements so far we describe the different techniques and point out ... More
Heavy Baryons - Different Facets of Experimental resultsMar 10 1999This paper reviews the experimental status of heavy baryons. It covers the aspec ts of production, spectroscopy and decay presenting recent results obtained in this fi eld. It closes with an outlook on further work on and with heavy baryons and their ... More
An A(oo)-structure on the cohomology ring of the symmetric group Sp with coefficients in FpFeb 01 2013Let p be a prime. Let FpSp be the group algebra of the symmetric group over the finite field Fp with |Fp|=p$. Let Fp be the trivial FpSp-module. We present a projective resolution PRes Fp of the module Fp and equip the Yoneda algebra Ext(Fp,Fp) with an ... More
On CM values of Borcherds products and harmonic weak Maass forms of weight oneAug 11 2012We show that the values of Borcherds products on Shimura varieties of orthogonal type at certain CM points are given in terms of coefficients of the holomorphic part of weight one harmonic weak Maass forms. Furthermore, we investigate the arithmetic properties ... More
Taut Submanifolds and FoliationsDec 27 2011Jan 03 2012We give an equivalent description of taut submanifolds of complete Riemannian manifolds as exactly those submanifolds whose normal exponential map has the property that every preimage of a point is a union of submanifolds. It turns out that every taut ... More