Results for "Christoph Somsen"

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Discovery of new stable and high-temperature Ti-Ta-X shape memory alloys from first principles calculationsMay 14 2019In conventional Ti-Ta shape memory alloys (SMAs), high (>100{\deg}C) transformation temperatures cannot be achieved without compromising the stability of the shape memory effect. A solution to this problem is the addition of other elements to form Ti-Ta-X ... More
Intrinsic room temperature ferromagnetism in Co-implanted ZnOMay 03 2008May 07 2008We report on the structural and magnetic properties of a cobalt-implanted ZnO film grown on a sapphire substrate. X-ray diffraction and transmission electron microscopy reveal the presence of a (10-10)-oriented hexagonal Co phase in the Al2O3 sapphire ... More
Discovery of new stable and high-temperature Ti-Ta-X shape memory alloys from first principles calculationsMay 14 2019Jul 24 2019In conventional Ti-Ta shape memory alloys (SMAs), high (>100{\deg}C) transformation temperatures cannot be achieved without compromising the stability of the shape memory effect. A solution to this problem is the addition of other elements to form Ti-Ta-X ... More
Discovery of $ω$-free high-temperature Ti-Ta-X shape memory alloys from first principles calculationsMay 14 2019Aug 01 2019The rapid degradation of the functional properties of many Ti-based alloys is due to the precipitation of the $\omega$ phase. In the conventional high-temperature shape memory alloy Ti-Ta the formation of this phase compromises completely the shape memory ... More
High temperature ferromagnetism in Co-implanted TiO2 rutileJul 09 2008We report on structural, magnetic and electronic properties of Co-implanted TiO2 rutile single crystals for different implantation doses. Strong ferromagnetism at room temperature and above is observed in TiO2 rutile plates after cobalt ion implantation, ... More
On sampling and interpolation by model setsSep 27 2018Nov 14 2018We refine a result of Matei and Meyer on stable sampling and stable interpolation for simple model sets. Our setting is model sets in locally compact second countable abelian groups and Fourier analysis of unbounded complex Radon measures as developed ... More
Equivalences of Smooth and Continuous Principal Bundles with Infinite-Dimensional Structure GroupApr 06 2006Jun 28 2012Let K be a a Lie group, modeled on a locally convex space, and M a finite-dimensional paracompact manifold with corners. We show that each continuous principal K-bundle over M is continuously equivalent to a smooth one and that two smooth principal K-bundles ... More
The diffeomorphism supergroup of a finite-dimensional supermanifoldApr 17 2009Sep 24 2009Using the categorical description of supergeometry we give an explicit construction of the diffeomorphism supergroup of a compact finite-dimensional supermanifold. The construction provides the diffeomorphism supergroup with the structure of a Frechet ... More
Deformation of cylinder knotsOct 24 2012Nov 20 2012Knots parametrized in cylinder coordinates by t -> (st, 3 + cos(nt), cos(mt + \phi)) share properties of Lissajous and billiard knots in a cylinder. We use these 'billiard knots in a flat solid torus' to study two topics: when is Z(s,n,m) equal to Z(s,m,n)? ... More
High dimensional finite elements for elliptic problems with multiple scales and stochastic dataMay 01 2003Multiple scale homogenization problems are reduced to single scale problems in higher dimension. It is shown that sparse tensor product Finite Element Methods (FEM) allow the numerical solution in complexity independent of the dimension and of the length ... More
Conscious observers clarify many worldsAug 03 2009In this brief note I argue that putting conscious observers at the center of the considerations clarifies and strengthens the many-worlds interpretation. The basic assumption, which seems extremely plausible based on our current understanding of the brain ... More
Towards global analysis of b --> s l^+ l^-Nov 15 2011Dec 15 2011Flavour changing neutral current decays mediated by b --> s l^+ l^- were under experimental investigation at B-factories and the Tevatron during the last decade and the final analysis are expected soon. Moreover, new data has been released this summer ... More
The Higgs Portal from LHC to ILCApr 20 2012Interpretations of searches for the Higgs boson are governed by model-dependent combinations of Higgs production cross sections and Higgs branching ratios. Mixing of the Higgs doublet with a hidden sector captures modifications from the Standard Model ... More
Wavelet-induced renormalization group for the Landau-Ginzburg modelSep 23 1999The scale hierarchy of wavelets provides a natural frame for renormalization. Expanding the order parameter of the Landau-Ginzburg/$\Phi^4$ model in a basis of compact orthonormal wavelets explicitly exhibits the coupling between scales that leads to ... More
On the Complexity of Finding Narrow ProofsApr 03 2012Sep 11 2012We study the complexity of the following "resolution width problem": Does a given 3-CNF have a resolution refutation of width k? We prove that the problem cannot be decided in time O(n^((k-3)/12)). This lower bound is unconditional and does not rely on ... More
Uniformly hyperbolic control theoryNov 25 2015May 30 2016This paper gives a summary of a body of work at the intersection of control theory and smooth nonlinear dynamics. The main idea is to transfer the concept of uniform hyperbolicity, central to the theory of smooth dynamical systems, to control-affine systems. ... More
Design and Implementation of a Master of Science in Information and Computer Sciences - An Inventory and retrospect for the last four yearsApr 16 2008This Master of Science in Computer and Information Sciences (MICS) is an international accredited master program that has been initiated in 2004 and started in September 2005. MICS is a research-oriented academic study of 4 semesters and a continuation ... More
A Simple Dynamic Mind-map Framework To Discover Associative Relationships in Transactional Data StreamsMay 09 2008In this paper, we informally introduce dynamic mind-maps that represent a new approach on the basis of a dynamic construction of connectionist structures during the processing of a data stream. This allows the representation and processing of recursively ... More
Superspace calculation of the three-loop dilatation operator of N=4 SYM theoryAug 19 2010Dec 07 2011We derive the three-loop dilatation operator of the flavor SU(2) subsector of N=4 supersymmetric Yang-Mills theory in the planar limit by a direct Feynman diagram calculation in N=1 superspace. The transcendentality three contributions which appear in ... More
On moduli spaces of flat connections with non-simply connected structure groupNov 12 1996We consider the moduli space of flat G-bundles over the twodimensional torus, where G is a real, compact, simple Lie group which is not simply connected. We show that the connected components that describe topologically non-trivial bundles are isomorphic ... More
Computational Complexity of Iterated Maps on the IntervalMar 31 2010Oct 11 2011The correct computation of orbits of discrete dynamical systems on the interval is considered. Therefore, an arbitrary-precision floating-point approach based on automatic error analysis is chosen and a general algorithm is presented. The correctness ... More
Theta vacuum in different gaugesJun 25 1998In some recent papers it is claimed that the physical significance of the vacuum angle theta for QCD-like theories depends on the chosen gauge condition. We criticise the arguments that were given in support of this claim, and show by explicit construction ... More
A remark on higher order RUE-resolution with EXTRUEJan 23 2009We show that a prominent counterexample for the completeness of first order RUE-resolution does not apply to the higher order RUE-resolution approach EXTRUE.
From Super-Yang-Mills to QCDDec 16 2004This article contains lecture notes of M. Shifman from the Saalburg Summer School 2004. The topic is supersymmetric Yang-Mills theory, in particular the gluino condensate in pure SUSY gluodynamics.
The origin of physical variations in the star formation lawJul 04 2013Dec 10 2013Observations of external galaxies and of local star-forming clouds in the Milky Way have suggested a variety of star formation laws, i.e., simple direct relations between the column density of star formation (Sigma_SFR: the amount of gas forming stars ... More
Status of Measurements and Interpretation of Total Real and Virtual Photon-Proton Cross SectionsNov 04 1999The status of measurements and interpretation of the proton structure function F2 is summarized. The measurements are subjected to DGLAP fits, from which the gluon density is extracted and a comparison to measurements of F2c is performed. The longitudinal ... More
A Higher Order Isoparametric Fictitious Domain Method for Level Set DomainsDec 08 2016We consider a new fictitious domain approach of higher order accuracy. To implement Dirichlet conditions we apply the classical Nitsche method combined with a facet-based stabilization (ghost penalty). Both techniques are combined with a higher order ... More
What is Information?Jan 22 2016Information is a precise concept that can be defined mathematically, but its relationship to what we call "knowledge" is not always made clear. Furthermore, the concepts "entropy" and "information", while deeply related, are distinct and must be used ... More
Survival Prediction with Limited Features: a Top Performing Approach from the DREAM ALS Stratification Prize4Life ChallengeDec 02 2016Survival prediction with small sets of features is a highly relevant topic for decision-making in clinical practice. I describe a method for predicting survival of amyotrophic lateral sclerosis (ALS) patients that was developed as a submission to the ... More
Mean-square stability and error analysis of implicit time-stepping schemes for linear parabolic SPDEs with multiplicative Wiener noise in the first derivativeAug 02 2012In this article, we extend a Milstein finite difference scheme introduced in [Giles & Reisinger(2011)] for a certain linear stochastic partial differential equation (SPDE), to semi- and fully implicit timestepping as introduced by [Szpruch(2010)] for ... More
Distinguishing mesoscopic quantum superpositions from statistical mixtures in periodically shaken double wellsOct 25 2011For Bose-Einstein condensates in double wells, N-particle Rabi-like oscillations often seem to be damped. Far from being a decoherence effect, the apparent damping can indicate the emergence of quantum superpositions in the many-particle quantum dynamics. ... More
A Birman-Krein-Vishik-Grubb theory for sectorial operatorsOct 16 2017Jul 31 2018We consider densely defined sectorial operators $A_\pm$ that can be written in the form $A_\pm=\pm iS+V$ with $\mathcal{D}(A_\pm)=\mathcal{D}(S)=\mathcal{D}(V)$, where both $S$ and $V\geq \varepsilon>0$ are assumed to be symmetric. We develop an analog ... More
On Nonlocal Parabolic Steady-State Equations of Cooperative or Competing SystemsAug 18 2010Some systems of parabolic equations with nonlocal initial conditions are studied. The systems arise when considering steady-state solutions to diffusive age-structured cooperative or competing species. Local and global bifurcation techniques are employed ... More
Analytic Dirac approximation for real linear algebraic groupsFeb 24 2010For a real linear algebraic group G let A(G) be the algebra of analytic vectors for the left regular representation of G on the space of superexponentially decreasing functions. We present an explicit Dirac sequence in A(G). Since A(G) acts on E for every ... More
A Reasoning System for a First-Order Logic of Limited BeliefMay 04 2017Logics of limited belief aim at enabling computationally feasible reasoning in highly expressive representation languages. These languages are often dialects of first-order logic with a weaker form of logical entailment that keeps reasoning decidable ... More
Exact Dragging of Inertial Axes by Cosmic Energy-Currents on the Past Light-ConeJun 18 2014We prove exact rotational dragging of local inertial axes (= spin axes of gyroscopes) by arbitrary cosmic energy-currents on the past light-cone of the gyroscope for linear perturbations of Friedmann-Robertson-Walker cosmologies. Hence the principle formulated ... More
Algorithmic transformation of multi-loop master integrals to a canonical basis with CANONICAMay 17 2017Nov 29 2017The integration of differential equations of Feynman integrals can be greatly facilitated by using a canonical basis. This paper presents the Mathematica package CANONICA, which implements a recently developed algorithm to automatize the transformation ... More
Smooth Extensions and Spaces of Smooth and Holomorphic MappingsNov 02 2005In this paper we present another notion of a smooth manifold with corners and relate it to the commonly used concept in the literature. Afterwards we introduce complex manifolds with corners and show that if $M$ is a compact (respectively complex) manifold ... More
From asymptotic hypothesis testing to entropy inequalitiesDec 12 2018This thesis addresses the interplay between asymptotic hypothesis testing and entropy inequalities in quantum information theory. In the first part of the thesis we focus on hypothesis testing. We consider two main settings; one can either fix quantum ... More
$h_{PI}$: The Citation Index for Principal InvestigatorsJul 17 2018A new citation index $h_{PI}$ for principal investigators (PIs) is defined in analogy to Hirsch's index $h$, but based on renormalized citations of a PI's papers. To this end, the authors of a paper are divided into two groups: PIs and non-PIs. A PI is ... More
Construction of Confidence IntervalsJul 10 2018Introductory texts on statistics typically only cover the classical "two sigma" confidence interval for the mean value and do not describe methods to obtain confidence intervals for other estimators. The present technical report fills this gap by first ... More
Technical Report: Inconsistency in Answer Set Programs and ExtensionsMay 31 2018Answer Set Programming (ASP) is a well-known problem solving approach based on nonmonotonic logic programs. HEX-programs extend ASP with external atoms for accessing arbitrary external information, which can introduce values that do not appear in the ... More
The turbulent formation of starsJun 14 2018Nov 30 2018How stars are born from clouds of gas is a rich physics problem whose solution will inform our understanding of not just stars but also planets, galaxies, and the universe itself. Star formation is stupendously inefficient. Take the Milky Way. Our galaxy ... More
Lepton Flavour Universality tests in $B$ decays as a probe for New PhysicsMay 11 2018In the Standard Model (SM), the coupling of the electroweak gauge bosons to the leptons is lepton flavour universal. Tests of this property constitute sensitive probes for new physics models that violate lepton flavour universality. Recent tests of lepton ... More
A Compositional Query Algebra for Second-Order Logic and Uncertain DatabasesJul 29 2008World-set algebra is a variable-free query language for uncertain databases. It constitutes the core of the query language implemented in MayBMS, an uncertain database system. This paper shows that world-set algebra captures exactly second-order logic ... More
On the Complexity of Nonrecursive XQuery and Functional Query Languages on Complex ValuesMar 23 2005Mar 24 2005This paper studies the complexity of evaluating functional query languages for complex values such as monad algebra and the recursion-free fragment of XQuery. We show that monad algebra with equality restricted to atomic values is complete for the class ... More
Analysis of Linear Difference Schemes in the Sparse Grid Combination TechniqueOct 02 2007Jun 08 2011Sparse grids are tailored to the approximation of smooth high-dimensional functions. On a $d$-dimensional tensor product space, the number of grid points is $N = \mathcal O(h^{-1} |\log h|^{d-1})$, where $h$ is a mesh parameter. The so-called combination ... More
A Categorical Formulation of Superalgebra and SupergeometryFeb 27 2008We reformulate superalgebra and supergeometry in completely categorical terms by a consequent use of the functor of points. The increased abstraction of this approach is rewarded by a number of great advantages. First, we show that one can extend supergeometry ... More
Lattice Green's Functions of the Higher-Dimensional Face-Centered Cubic LatticesAug 10 2011Mar 11 2013We study the face-centered cubic lattice (fcc) in up to six dimensions. In particular, we are concerned with lattice Green's functions (LGF) and return probabilities. Computer algebra techniques, such as the method of creative telescoping, are used for ... More
A Fast Approach to Creative TelescopingApr 19 2010Jun 27 2011In this note we reinvestigate the task of computing creative telescoping relations in differential-difference operator algebras. Our approach is based on an ansatz that explicitly includes the denominators of the delta parts. We contribute several ideas ... More
Leggett-Garg inequalities cannot be violated in quantum measurementsAug 08 2019Aug 09 2019Leggett and Garg derived inequalities that probe the boundaries of classical and quantum physics by putting limits on the properties that classical objects can have. Historically, it has been suggested that Leggett-Garg inequalities are easily violated ... More
The combinatorial essence of supercompactnessDec 09 2010We introduce combinatorial principles that characterize strong compactness and supercompactness for inaccessible cardinals but also make sense for successor cardinals. Their consistency is established from what is supposedly optimal. Utilizing the failure ... More
Quasi-homogeneity of the moduli space of stable maps to homogeneous spaces (II)Dec 28 2018Let $G$ be a connected, simply connected, simple, complex, linear algebraic group. Let $P$ be an arbitrary parabolic subgroup of $G$. Let $X=G/P$ be the $G$-homogeneous projective space attached to this situation. Let $d\in H_2(X)$ be a degree. Let $\overline{M}_{0,3}(X,d)$ ... More
The Face Structure and Geometry of Marked Order PolyhedraOct 05 2016Nov 29 2017We study a class of polyhedra associated to marked posets. Examples of these polyhedra are Gelfand-Tsetlin polytopes and cones, as well as Berenstein-Zelevinsky polytopes, all of which have appeared in the representation theory of semi-simple Lie algebras. ... More
Dense Dirac combs in Euclidean space with pure point diffractionFeb 21 2003May 19 2004Regular model sets, describing the point positions of ideal quasicrystallographic tilings, are mathematical models of quasicrystals. An important result in mathematical diffraction theory of regular model sets, which are defined on locally compact Abelian ... More
A Schrödinger Operator Approach to Higher Spin XXZ Systems on General GraphsNov 24 2018Feb 11 2019We consider the spin-$J$ XXZ-Hamiltonian on general graphs $\mathcal{G}$ and show its equivalence to a direct sum of discrete many-particle Schr\"odinger type operators on what we call "$N$-particle graphs with maximal local occupation number $M$", where ... More
Characteristic Polynomials of Symmetric Matrices over the Univariate Polynomial RingOct 21 2016Viewing a bivariate polynomial f in R[x,t] as a family of univariate polynomials in t parametrized by real numbers x, we call f real rooted if this family consists of monic polynomials with only real roots. If f is the characteristic polynomial of a symmetric ... More
Bifurcation of Positive Equilibria in Nonlinear Structured Population Models with Varying Mortality RatesFeb 09 2010A parameter-dependent model involving nonlinear diffusion for an age-structured population is studied. The parameter measures the intensity of the mortality. A bifurcation approach is used to establish existence of positive equilibrium solutions.
Global Bifurcation of Positive Equilibria in Nonlinear Population ModelsJul 07 2009Existence of nontrivial nonnegative equilibrium solutions for age structured population models with nonlinear diffusion is investigated. Introducing a parameter measuring the intensity of the fertility, global bifurcation is shown of a branch of positive ... More
The impact of partially missing communities~on the reliability of centrality measuresSep 20 2017Network data is usually not error-free, and the absence of some nodes is a very common type of measurement error. Studies have shown that the reliability of centrality measures is severely affected by missing nodes. This paper investigates the reliability ... More
On Low-Dimensional SolvmanifoldsMar 17 2009Aug 31 2009A nilmanifold resp. solvmanifold is a compact homogeneous space of a connected and simply-connected nilpotent resp. solvable Lie group by a lattice, i.e. a discrete co-compact subgroup. There is an easy criterion for nilpotent Lie groups which enables ... More
Tractability results for the weighted star-discrepancyJul 22 2013Dec 05 2013The weighted star-discrepancy has been introduced by Sloan and Wo{\'z}niakowski to reflect the fact that in multidimensional integration problems some coordinates of a function may be more important than others. It provides upper bounds for the error ... More
On rational homotopy and minimal modelsFeb 25 2019Mar 13 2019We prove a result that enables us to calculate the rational homotopy of a wide class of spaces by the theory of minimal models.
On the transfer reducibility of certain Farrell-Hsiang groupsSep 30 2014We show how the existing proof of the Farrell-Jones Conjecture for virtually poly-$\mathbb{Z}$-groups can be improved to rely only on the usual inheritance properties in combination with transfer reducibility as a sufficient criterion for the validity ... More
Skew divided difference operators in the Nichols algebra associated to a finite Coxeter groupApr 17 2018Let $(W,S)$ be a finite Coxeter system with root system $R$ and with set of positive roots $R^+$. For $\alpha\in R$, $v,w\in W$, we denote by $\partial_\alpha$, $\partial_w$ and $\partial_{w/v}$ the divided difference operators and skew divided difference ... More
Curve neighborhoods and minimal degrees in quantum productsDec 13 2016Let $G$ be a connected, simply connected, simple, complex, linear algebraic group. Let $P$ be an arbitrary parabolic subgroup of $G$. Let $X=G/P$ be the $G$-homogeneous projective space attached to this situation. We consider the (small) quantum cohomology ... More
Poisson transforms for differential formsApr 01 2016We give a construction of a Poisson transform mapping density valued differential forms on generalized flag manifolds to differential forms on the corresponding Riemannian symmetric spaces, which can be described entirely in terms of finite dimensional ... More
The Propagation Depth of Local ConsistencyJun 18 2014We establish optimal bounds on the number of nested propagation steps in $k$-consistency tests. It is known that local consistency algorithms such as arc-, path- and $k$-consistency are not efficiently parallelizable. Their inherent sequential nature ... More
On Moduli of G-bundles over Curves for exceptional GSep 22 1997Oct 02 1997Let $G$ be a simple and simply connected complex Lie group, ${\goth{g}}$ its Lie algebra. I remove the restriction ``$G$ is of classical type or $G_2$'' made on $G$ in the papers of Beauville, Laszlo and myself [L-S] and [B-L-S] on the moduli of principal ... More
Creative Telescoping for Holonomic FunctionsJul 17 2013The aim of this article is twofold: on the one hand it is intended to serve as a gentle introduction to the topic of creative telescoping, from a practical point of view; for this purpose its application to several problems is exemplified. On the other ... More
Eliminating Human Insight: An Algorithmic Proof of Stembridge's TSPP TheoremJun 04 2009We present a new proof of Stembridge's theorem about the enumeration of totally symmetric plane partitions using the methodology suggested in the recent Koutschan-Kauers-Zeilberger semi-rigorous proof of the Andrews-Robbins q-TSPP conjecture. Our proof ... More
A Simple Framework to Typify Social Bibliographic CommunitiesSep 16 2008Social Communities in bibliographic databases exist since many years, researchers share common research interests, and work and publish together. A social community may vary in type and size, being fully connected between participating members or even ... More
Holographic flavour in the N=1 Polchinski-Strassler backgroundApr 26 2007To endow the N=1* SYM theory with quarks, we embed D7-brane probes into its gravity dual, known as the Polchinski-Strassler background. The non-vanishing 3-form flux G_3 in the background is dual to mass terms for the three adjoint chiral superfields, ... More
Discrete Anomalies of Binary GroupsJul 10 2008Nov 17 2008We derive the discrete anomaly conditions for the binary tetrahedral group T' as well as the binary dihedral groups Q_2n. The ambiguities of embedding these finite groups into SU(2) and SU(3) lead to various possible definitions of the discrete indices ... More
Trimaximal TM1 neutrino mixing in S4 with spontaneous CP violationJun 10 2013Jul 18 2013The measurement of the reactor angle by the Daya Bay and RENO experiments in 2012 has ruled out the tri-bimaximal paradigm. Adopting an S4 family symmetry, we propose direct models of the trimaximal type TM1 in which the tri-bimaximal Klein symmetry of ... More
Automating Access Control Logics in Simple Type Theory with LEO-IIJan 23 2009Mar 04 2009Garg and Abadi recently proved that prominent access control logics can be translated in a sound and complete way into modal logic S4. We have previously outlined how normal multimodal logics, including monomodal logics K and S4, can be embedded in simple ... More
A simple C++ library for manipulating scientific data sets as structured dataJul 30 1999Representing scientific data sets efficiently on external storage usually involves converting them to a byte string representation using specialized reader/writer routines. The resulting storage files are frequently difficult to interpret without these ... More
Groupe de Picard de la variét\e de modules des thêta-caracteristiques des courbes planesMar 28 1994Nous calculons le groupe de Picard de l'espace des modules $\Theta_{\planp}(d)$ des th\^eta-caract\'eristiques des courbes planes (non forc\'ement lisses) de degr\'e $d$. Nous montrons que pour $d\ge 6$, le groupe de Picard de la composante paire est ... More
Dynamics of $K^+$ Production in Heavy Ion Collisions close to ThresholdJul 01 2005In this article the production of $K^+$ at energies close to the threshold is studied in detail. The production mechanisms, the influence of in-medium effects, cross sections, the nuclear equation of state and the dynamics of the nucleons on the kaon ... More
The INTEGRAL Core Observing ProgrammeFeb 01 2001The Core Programme (CP) of the INTEGRAL mission is defined as the portion of the scientific observing programme covering the guaranteed time observations for the PI collaborations and other members of the INTEGRAL Science Working Team. During the first ... More
Toward a comprehensive model for feedback by active galactic nuclei: new insights from M87 observations by LOFAR, Fermi and H.E.S.SMar 21 2013Oct 24 2013Feedback by active galactic nuclei (AGNs) appears to be critical in balancing radiative cooling of the low-entropy gas at the centers of galaxy clusters and in mitigating the star formation of elliptical galaxies. New observations of M87 enable us to ... More
Tentative observation of a gamma-ray line at the Fermi LATOct 10 2012Using 43 months of public gamma-ray data from the Fermi Large Area Telescope, we find in regions close to the Galactic center at energies of 130 GeV a 4.6 sigma excess that is not inconsistent with a gamma-ray line from dark matter annihilation. When ... More
A Tentative Gamma-Ray Line from Dark Matter Annihilation at the Fermi Large Area TelescopeApr 12 2012Aug 08 2012The observation of a gamma-ray line in the cosmic-ray fluxes would be a smoking-gun signature for dark matter annihilation or decay in the Universe. We present an improved search for such signatures in the data of the Fermi Large Area Telescope (LAT), ... More
Comment on "Separability of quantum states and the violation of Bell-type inequalities"Oct 05 2004The statement of E.R. Loubenets, Phys. Rev. A 69, 042102 (2004), that separable states can violate classical probabilistic constraints is based on a misleading definition of classicality, which is much narrower than Bell's concept of local hidden variables. ... More
The Foundations of Quantum Information and Feasible ExperimentsMar 12 2001This thesis consists of four parts. In the first part it is shown that optimal universal cloning of photons can be realized with the help of stimulated emission. Possible schemes based on three-level systems and on parametric down-conversion are analyzed ... More
Theory status of $b\to s \ell^+\ell^-$ decays and their combined analysisAug 15 2012The experimental information on b --> s l^+ l^- decays has grown enormously during the last couple of years due to BaBar, Belle, CDF and LHCb. Especially, exclusive modes B --> K^(*) l^+ l^-, which have the largest rate and are easily accessible experimentally, ... More
Maintaining prediction quality under the condition of a growing knowledge spaceAug 03 2015Aug 11 2015Intelligence can be understood as an agent's ability to predict its environment's dynamic by a level of precision which allows it to effectively foresee opportunities and threats. Under the assumption that such intelligence relies on a knowledge space ... More
Removing the stabilization parameter in fitted and unfitted symmetric Nitsche formulationsMar 02 2016In many situations with finite element discretizations it is desirable or necessary to impose boundary or interface conditions not as essential conditions -- i.e. through the finite element space -- but through the variational formulation. One popular ... More
A Quantum Mechanical Bound for Space-Energy Cost with Respect to the Von Neumann EntropyOct 14 2016This thesis discusses the possibility of uncertainty relations for space and energy given a state of fixed entropy. In particular, it discusses the results in the paper of Dam/Nguyen. There, the authors propose a lower bound for the mixed cost in energy ... More
Entwicklung eines Reputationssystems für cyber-physikalische Systeme am Beispiel des inHMotion ForschungsprojektesSep 20 2016Through the continued progress and advances of networking technology and also through efforts like Industry 4.0, SmartGrid, SmartCities, systems, that have been self-sustaining for the most part are now forming networked Cyber-physical Systems (CPS). ... More
Tweedie distributions for fitting semicontinuous health care utilization cost dataAug 17 2016We explore a statistical distribution that can simultaneously model the probability of zero outcome for non-users of health care utilization and continuous costs for users. We compare this distribution to other com- monly used models on example data and ... More
The role of turbulence, magnetic fields and feedback for star formationJun 09 2016Star formation is inefficient. Only a few percent of the available gas in molecular clouds forms stars, leading to the observed low star formation rate (SFR). The same holds when averaged over many molecular clouds, such that the SFR of whole galaxies ... More
The non-locality of Markov chain approximations to two-dimensional diffusionsMay 20 2016Nov 07 2016In this short paper, we consider discrete-time Markov chains on lattices as approximations to continuous-time diffusion processes. The approximations can be interpreted as finite difference schemes for the generator of the process. We derive conditions ... More
On $B\to K^{(*)}\bar νν$ decays in and beyond the Standard ModelOct 15 2015In this talk an analysis of the rare exclusive $B$ decays $B\to K\nu\bar\nu$ and $B\to K^{*}\nu\bar\nu$ within and beyond the Standard Model is presented. Combining new form factor determinations from lattice QCD with light-cone sum rule results and including ... More
The Planck length and the constance of the speed of light in two time dimensionsNov 26 2016In special relativity and quantum field theory, the vacuum speed of light is assumed to be constant; the range of validity of general relativity is determined by the Planck length. However, there has been no convincing theory yet explaining the constance ... More
Parallelization of continuous and discontinuous Galerkin dual-primal Isogeometric tearing and interconnecting methodsNov 24 2016In this paper we investigate the parallelization of dual-primal isogeometric tearing and interconnecting (IETI-DP) type methods for solving large-scale continuous and discontinuous Galerkin systems of equations arising from Isogeometric analysis of elliptic ... More
Uniformly hyperbolic control theoryNov 25 2015Nov 02 2016This paper gives a summary of a body of work at the intersection of control theory and smooth nonlinear dynamics. The main idea is to transfer the concept of uniform hyperbolicity, central to the theory of smooth dynamical systems, to control-affine systems. ... More
On rational homotopy and minimal modelsFeb 25 2019We prove a result that enables us to calculate the rational homotopy of a wide classs of spaces by the theory of minimal models.The latter are derivided from properies of the de Rham complex.
Staircase polygons: moments of diagonal lengths and column heightsMay 30 2006We consider staircase polygons, counted by perimeter and sums of k-th powers of their diagonal lengths, k being a positive integer. We derive limit distributions for these parameters in the limit of large perimeter and compare the results to Monte-Carlo ... More