Results for "Björn Alling"

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Structure and Bonding in Amorphous Cr1-xCx Nanocomposite Thin Films: X-ray Absorption Spectra and First-Principles CalculationNov 25 2016The local structure and chemical bonding in two-phase amorphous Cr$_{1-x}$C$_{x}$ nanocomposite thin films are investigated by Cr $K$-edge ($1s$) X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopies ... More
Anomalous phonon lifetime shortening in paramagnetic CrN caused by magneto-lattice coupling: A combined spin and ab initio molecular dynamics studyFeb 08 2018We study the mutual coupling of spin fluctuations and lattice vibrations in paramagnetic CrN by combining atomistic spin dynamics and ab initio molecular dynamics. The two degrees of freedom are dynamically coupled leading to non-adiabatic effects. Those ... More
Finite temperature elastic constants of paramagnetic materials within the disordered local moment picture from ab initio molecular dynamics calculationsApr 29 2016Jun 09 2016We present a theoretical scheme to calculate the elastic constants of magnetic materials in the high-temperature paramagnetic state. Our approach is based on a combination of disordered local moments picture and ab initio molecular dynamics (DLM-MD). ... More
Origin of the anomalous piezoelectric response in wurtzite Sc$_x$Al$_{1-x}$N alloysMar 17 2010The origin of the anomalous, 400% increase of the piezoelectric coefficient in Sc$_x$Al$_{1-x}$N alloys is revealed. Quantum mechanical calculations show that the effect is intrinsic. It comes from a strong change in the response of the internal atomic ... More
The role of N defects in paramagnetic CrN at finite temperatures from first-principlesOct 20 2014Simulations of defects in paramagnetic materials at high temperature constitute a formidable challenge to solid state theory due to the interaction of magnetic disorder, vibrations, and structural relaxations. CrN is a material where these effects are ... More
Efficient and accurate determination of lattice-vacancy diffusion coefficients via non equilibrium ab initio molecular dynamicsSep 15 2015Feb 13 2016We revisit the color-diffusion algorithm [P. C. Aeberhard et al., Phys. Rev. Lett. 108, 095901 (2012)] in nonequilibrium ab initio molecular dynamics (NE-AIMD), and propose a simple efficient approach for the estimation of monovacancy jump rates in crystalline ... More
Vibrational free energy and phase stability of paramagnetic and antiferromagnetic CrN from ab-initio molecular dynamicsMar 19 2014We present a theoretical first-principles method to calculate the free energy of a magnetic system in its high-temperature paramagnetic phase, including vibrational, electronic, and magnetic contributions. The method for calculating free energies is based ... More
Obstacle and Dirichlet problems on arbitrary nonopen sets, and fine topologyAug 24 2012We study the double obstacle problem for p-harmonic functions on arbitrary bounded nonopen sets E in quite general metric spaces. The Dirichlet and single obstacle problems are included as special cases. We obtain Adams' criterion for the solubility of ... More
Functional Uniform Priors for Nonlinear ModellingOct 19 2011This paper considers the topic of finding prior distributions when a major component of the statistical model depends on a nonlinear function. Using results on how to construct uniform distributions in general metric spaces, we propose a prior distribution ... More
Well-posedness and Stability of Linear Port-Hamiltonian Systems with Nonlinear Boundary FeedbackJun 09 2015Apr 25 2016Boundary feedback stabilisation of linear port-Hamiltonian systems on an interval is considered. Generation and stability results already known for linear feedback are extended to nonlinear dissipative feedback, both to static feedback control and dynamic ... More
The Dirichlet problem for p-harmonic functions on the topologist's combApr 05 2013In this paper we study the Perron method for solving the p-harmonic Dirichlet problem on the topologist's comb. For functions which are bounded and continuous at the accessible points, we obtain invariance of the Perron solutions under arbitrary perturbations ... More
Anharmonicity changes the solid solubility of an alloy at high temperaturesMar 09 2015Sep 23 2015We have developed a method to accurately and efficiently determine the vibrational free energy as a function of temperature and volume for substitutional alloys from first principles. Taking Ti$_{1-x}$Al$_x$N alloy as a model system, we calculate the ... More
Embedded Markov chain approximations in Skorokhod topologiesSep 16 2014In order to approximate a continuous time stochastic process by discrete time Markov chains one has several options to embed the Markov chains into continuous time processes. On the one hand there is the Markov embedding, which uses exponential waiting ... More
Radiative corrections to neutralino annihilation: Recent developmentsNov 30 2010Evaluating the relic density of dark matter is an interesting possibility to constrain the parameter space of new physics models. However, this calculation is affected by several sources of uncertainty. On the particle physics side, considerable progress ... More
Flavour Violation in GMSB Scenarios: Constraints and PhenomenologyOct 07 2008We present an extensive analysis of low-energy, electroweak precision, and cosmological constraints in the Minimal Supersymmetric Standard Model (MSSM) with Gauge-Mediated Supersymmetry Breaking (GMSB) and including the possibility of Non-Minimal Flavour ... More
Sharp exponents and a Wiener type condition for boundary regularity of quasiminimizersApr 30 2015We obtain a sufficient condition for boundary regularity of quasiminimizers of the p-energy integral in terms of a Wiener type sum of power type. The exponent in the sum is independent of the dimension and is explicitly expressed in terms of p and the ... More
The variational capacity with respect to nonopen sets in metric spacesOct 01 2012We pursue a systematic treatment of the variational capacity on metric spaces and give full proofs of its basic properties. A novelty is that we study it with respect to nonopen sets, which is important for Dirichlet and obstacle problems on nonopen sets, ... More
Feller Processes: The Next Generation in Modeling. Brownian Motion, Lévy Processes and BeyondSep 24 2010Dec 06 2010We present a simple construction method for Feller processes and a framework for the generation of sample paths of Feller processes. The construction is based on state space dependent mixing of L\'evy processes. Brownian Motion is one of the most frequently ... More
Approximating Probability Densities by Iterated Laplace ApproximationsMar 17 2011The Laplace approximation is an old, but frequently used method to approximate integrals for Bayesian calculations. In this paper we develop an extension of the Laplace approximation, by applying it iteratively to the residual, i.e., the difference between ... More
Background Rejection of n$^+$ Surface Events in GERDA Phase IIMay 12 2016The GERDA experiment searches for neutrinoless double beta ($0\nu\beta\beta$) decay in $^{76}$Ge using an array of high purity germanium (HPGe) detectors immersed in liquid argon (LAr). Phase II of the experiment uses 30 new broad energy germanium (BEGe) ... More
A renormalization fixed point for Lorenz mapsAug 05 2009Mar 14 2010A Lorenz map is a Poincar\'e map for a three-dimensional Lorenz flow. We describe the theory of renormalization for Lorenz maps with a critical point and prove that a restriction of the renormalization operator acting on such maps has a hyperbolic fixed ... More
Squark and gaugino hadroproduction and decays in non-minimal flavour violating supersymmetryAug 28 2007Sep 24 2007We implement non-minimal flavour violation (NMFV) in the MSSM at low scale. In this framework, we propose benchmark points for the mSUGRA scenario including non-minimal flavour violation by evaluating a number of experimental low-energy, electroweak precision ... More
Effect of SUSY-QCD corrections to neutralino annihilation on the cold dark matter relic density in the Higgs funnelSep 14 2007We present a complete calculation of the QCD and SUSY-QCD corrections to neutralino pair annihilation into bottom quark-antiquark pairs through exchange of a pseudoscalar Higgs boson, which is the dominant process in the cosmological A-funnel region of ... More
Strict Upper Limits on the Carbon-to-Oxygen Ratios of Eight Hot Jupiters from Self-Consistent Atmospheric RetrievalApr 28 2015The elemental compositions of hot Jupiters are informative relics of planet formation that can help us answer long-standing questions regarding the origin and formation of giant planets. Here, I present the main conclusions from a comprehensive atmospheric ... More
Exponential transforms, resultants and momentsDec 04 2012We give an overview of some recent developments concerning harmonic and other moments of plane domains, their relationship to the Cauchy and exponential transforms, and to the meromorphic resultant and elimination function. The paper also connects to ... More
The Cartan, Choquet and Kellogg properties for the fine topology on metric spacesOct 20 2014We prove the Cartan and Choquet properties for the fine topology on a complete metric space equipped with a doubling measure supporting a $p$-Poincar\'e inequality, $1 < p< \infty$. We apply these key tools to establish a fine version of the Kellogg property, ... More
Spatio-temporal Video Parsing for Abnormality DetectionFeb 22 2015Abnormality detection in video poses particular challenges due to the infinite size of the class of all irregular objects and behaviors. Thus no (or by far not enough) abnormal training samples are available and we need to find abnormalities in test data ... More
Stationary quantum coherence and transport in disordered networksMay 29 2013We examine the excitation transport across quantum networks that are continuously driven by a constant and incoherent light source. In particular we investigate the coherence properties of incoherently driven networks by employing recent tools from entanglement ... More
Critical points of Green's function and geometric function theoryDec 07 2009We study questions related to critical points of the Green's function of a bounded multiply connected domain in the complex plane. The motion of critical points, their limiting positions as the pole approaches the boundary and the differential geometry ... More
Convolutional RNN: an Enhanced Model for Extracting Features from Sequential DataFeb 18 2016Mar 01 2016Traditional convolutional layers extract features from patches of data by applying a non-linearity on an affine function of the input. We propose a model that enhances this feature extraction process for the case of sequential data, by feeding patches ... More
Momentum and position detection in nanoelectromechanical systems beyond Born and Markov approximationsDec 21 2010We propose and analyze different schemes to probe the quantum nature of nanoelectromechanical systems (NEMS) by a tunnel junction detector. Using the Keldysh technique, we are able to investigate the dynamics of the combined system for an arbitrary ratio ... More
Physical Measures for Infinitely Renormalizable Lorenz MapsDec 27 2014A physical measure on the attractor of a system describes the statistical behavior of typical orbits. An example occurs in unimodal dynamics. Namely, all infinitely renormalizable unimodal maps have a physical measure. For Lorenz dynamics, even in the ... More
On the Hyperbolicity of Lorenz RenormalizationMay 03 2012We consider infinitely renormalizable Lorenz maps with real critical exponent $\alpha>1$ and combinatorial type which is monotone and satisfies a long return condition. For these combinatorial types we prove the existence of periodic points of the renormalization ... More
Likelihood Ratio Tests for a Dose-Response Effect using Multiple Nonlinear Regression ModelsOct 21 2015We consider the problem of testing for a dose-related effect based on a candidate set of (typically nonlinear) dose-response models using likelihood-ratio tests. For the considered models this reduces to assessing whether the slope parameter in these ... More
Fast Directional Computation for the High Frequency Helmholtz Kernel in Two DimensionsFeb 28 2008This paper introduces a directional multiscale algorithm for the two dimensional $N$-body problem of the Helmholtz kernel with applications to high frequency scattering. The algorithm follows the approach in [Engquist and Ying, SIAM Journal on Scientific ... More
How to Distinguish between Cloudy Mini-Neptunes and Water/Volatile-Dominated Super-EarthsJun 26 2013One of the most profound questions about the newly discovered class of low-density super-Earths is whether these exoplanets are predominately H2-dominated mini-Neptunes or volatile-rich worlds with gas envelopes dominated by H2O, CO2, CO, CH4, or N2. ... More
Counting attractors in synchronously updated random Boolean networksDec 16 2004Despite their apparent simplicity, random Boolean networks display a rich variety of dynamical behaviors. Much work has been focused on the properties and abundance of attractors. We here derive an expression for the number of attractors in the special ... More
The Mazurkiewicz distance and sets that are finitely connected at the boundaryNov 20 2013We study local connectedness, local accessibility and finite connectedness at the boundary, in relation to the compactness of the Mazurkiewicz completion of a bounded domain in a metric space. For countably connected planar domains we obtain a complete ... More
The Petrovskiĭ criterion and barriers for degenerate and singular p-parabolic equationsSep 08 2015Mar 01 2016In this paper we obtain sharp Petrovskii criteria for the p-parabolic equation, both in the degenerate case p>2 and the singular case 1<p<2. We also give an example of an irregular boundary point at which there is a barrier, thus showing that regularity ... More
The Dirichlet problem for p-harmonic functions with respect to arbitrary compactificationsApr 29 2016We study the Dirichlet problem for p-harmonic functions on metric spaces with respect to arbitrary compactifications. A particular focus is on the Perron method, and as a new approach to the invariance problem we introduce Sobolev-Perron solutions. We ... More
The annular decay property and capacity estimates for thin annuliDec 21 2015We obtain upper and lower bounds for the nonlinear variational capacity of thin annuli in weighted $\mathbf{R}^n$ and in metric spaces, primarily under the assumptions of an annular decay property and a Poincar\'e inequality. In particular, if the measure ... More
Quasiopen and p-path open sets, and characterizations of quasicontinuitySep 08 2015In this paper we give various characterizations of quasiopen sets and quasicontinuous functions on metric spaces. For complete metric spaces equipped with a doubling measure supporting a p-Poincar\'e inequality we show that quasiopen and p-path open sets ... More
Minima of quasisuperminimizersMay 19 2015Let u_i be a Q_i-quasisuperminimizer, i=1,2, and u=min{u_1,u_2}, where 1 <= Q_1 <= Q_2. Then u is a quasisuperminimizer, and we improve upon the known upper bound (due to Kinnunen and Martio) for the optimal quasisuperminimizing constant Q of u. We give ... More
An axiomatic approach to gradients with applications to Dirichlet and obstacle problems beyond function spacesJan 27 2015We develop a framework for studying variational problems in Banach spaces with respect to gradient relations, which encompasses many of the notions of generalized gradients that appear in the literature. We stress the fact that our approach is not dependent ... More
The weak Cartan property for the p-fine topology on metric spacesOct 30 2013We study the p-fine topology on complete metric spaces equipped with a doubling measure supporting a p-Poincare inequality, 1 < p< oo. We establish a weak Cartan property, which yields characterizations of the p-thinness and the p-fine continuity, and ... More
Configurational order-disorder induced metal-nonmetal transition in B$_{13}$C$_{2}$ studied with first-principles superatom-special quasirandom structure methodAug 31 2015Due to a large discrepancy between theory and experiment, the electronic character of crystalline boron carbide B$_{13}$C$_{2}$ has been a controversial topic in the field of icosahedral boron-rich solids. We demonstrate that this discrepancy is removed ... More
A unified cluster expansion method applied to the configurational thermodynamics of cubic TiAlNDec 14 2010We study the thermodynamics of cubic Ti1-xAlxN using a unified cluster expansion approach for the alloy problem. The purely configurational part of the alloy Hamiltonian is expanded in terms of concentration and volume dependent effective cluster interactions. ... More
Nonlinear left and right eigenvectors for max-preserving mapsSep 20 2016It is shown that max-preserving maps (or join-morphisms) on the positive orthant in Euclidean $n$-space endowed with the component-wise partial order give rise to a semiring. This semiring admits a closure operation for maps that generate stable dynamical ... More
Flux-Dependent Level Attraction in Double-Dot Aharonov-Bohm InterferometersOct 24 2001Jun 04 2002We study electron transport through a closed Aharonov-Bohm interferometer containing two single-level quantum dots. The quantum-dot levels are coupled to each other indirectly via the leads. We find that this coupling yields signatures of an effective ... More
Global continua of periodic solutions of singular first-order Hamiltonian systems of N-vortex typeApr 06 2016The paper deals with singular first order Hamiltonian systems of the form \[ \Gamma_k\dot{z}_k(t)=J\nabla_{z_k} H\big(z(t)\big),\quad z_k(t) \in \Omega \subset \mathbb{R}^2,\ k=1,\dots,N, \] where $J\in\mathbb{R}^{2\times2}$ defines the standard symplectic ... More
On the Finite Dimensionality of Spaces of Absolutely Convergent Fourier TransformsMay 12 2013We extend the result of K. Karlander [Math. Scand. 80 (1997)] regarding finite dimensionality of spaces of absolutely convergent Fourier transforms.
Devices with electrically tunable topological insulating phasesJan 09 2013Feb 28 2013Solid-state topological insulating phases, characterized by spin-momentum locked edge modes, provide a powerful route for spin and charge manipulation in electronic devices. We propose to control charge and spin transport in the helical edge modes by ... More
Parity measurement in topological Josephson junctionsMay 31 2013We study the properties of a topological Josephson junction made of both edges of a 2D topological insulator. We show that, due to fermion parity pumping across the bulk, the global parity of the junction has a clear signature in the periodicity and critical ... More
On a generalization of the preconditioned Crank-Nicolson Metropolis algorithmApr 14 2015Oct 12 2016Metropolis algorithms for approximate sampling of probability measures on infinite dimensional Hilbert spaces are considered and a generalization of the preconditioned Crank-Nicolson (pCN) proposal is introduced. The new proposal is able to incorporate ... More
Neutralino annihilation to quarks with SUSY-QCD correctionsNov 10 2008The calculation of the cosmological relic density of the dark matter candidate within supersymmetric models is an interesting possibility to obtain additional constraints on the supersymmetric parameter space with respect to collider, electroweak precision, ... More
Stability and Complexity of Minimising Probabilistic AutomataApr 26 2014May 01 2014We consider the state-minimisation problem for weighted and probabilistic automata. We provide a numerically stable polynomial-time minimisation algorithm for weighted automata, with guaranteed bounds on the numerical error when run with floating-point ... More
Risk aggregation and stochastic claims reserving in disability insuranceJan 15 2014Aug 26 2014We consider a large, homogeneous portfolio of life or disability annuity policies. The policies are assumed to be independent conditional on an external stochastic process representing the economic-demographic environment. Using a conditional law of large ... More
AC-Conductance through an Interacting Quantum DotOct 15 2009We investigate the linear ac-conductance for tunneling through an arbitrary interacting quantum dot in the presence of a finite dc-bias. In analogy to the well-known Meir-Wingreen formula for the dc case, we are able to derive a general formula for the ... More
Hybrid model calculations of direct photons in high-energy nuclear collisionsMay 28 2009Mar 04 2010Direct photon emission in heavy-ion collisions is calculated within a relativistic micro+macro hybrid model and compared to the microscopic transport model UrQMD. In the hybrid approach, the high-density part of the evolution is replaced by an ideal 3-dimensional ... More
Deep Impact: Unintended consequences of journal rankJan 16 2013May 10 2013Most researchers acknowledge an intrinsic hierarchy in the scholarly journals ('journal rank') that they submit their work to, and adjust not only their submission but also their reading strategies accordingly. On the other hand, much has been written ... More
Nonuniform sampling and multiscale computationSep 10 2013Aug 24 2014In homogenization theory and multiscale modeling, typical functions satisfy the scaling law $f^{\epsilon}(x) = f(x,x/\epsilon)$, where $f$ is periodic in the second variable and $\epsilon$ is the smallest relevant wavelength, $0<\epsilon\ll1$. Our main ... More
Ranking and Selection: A New Sequential Bayesian Procedure for Use with Common Random NumbersOct 24 2014We want to select the best systems out of a given set of systems (or rank them) with respect to their expected performance. The systems allow random observations only and we assume that the joint observation of the systems has a multivariate normal distribution ... More
Stability and Stabilization of Infinite-dimensional Linear Port-Hamiltonian SystemsDec 16 2013Stability and stabilization of linear port-Hamiltonian systems on infinite-dimensional spaces are investigated. This class is general enough to include models of beams and waves as well as transport and Schr\"odinger equations with boundary control and ... More
Measuring the Kondo Cloud by Current Cross Correlations in Helical LiquidsOct 24 2013Feb 02 2014The Kondo cloud, represented by the correlations between the magnetic moment and the spin density in the leads of a Kondo setup, is until now eluding its observation. We exploit the unique coupling of spin and direction of motion of the recently discovered ... More
Random maps and attractors in random Boolean networksMay 19 2005Despite their apparent simplicity, random Boolean networks display a rich variety of dynamical behaviors. Much work has been focused on the properties and abundance of attractors. The topologies of random Boolean networks with one input per node can be ... More
Revealing proton shape fluctuations with incoherent diffraction at high energyJul 06 2016Aug 30 2016The differential cross section of exclusive diffractive vector meson production in electron proton collisions carries important information on the geometric structure of the proton. More specifically, the coherent cross section as a function of the transferred ... More
Tuning of the strange quark mass with optimal reweightingJan 26 2015Quark mass reweighting can be used to tune the mass of dynamical quarks. The basic idea is to use gauge field ensembles generated at some bare mass parameters to evaluate observables at different bare sea quark masses. This involves the computation of ... More
Partial Balayage on Riemannian ManifoldsMay 10 2016A general theory of partial balayage on Riemannian manifolds is developed, with emphasis on compact manifolds. Partial balayage is an operation of sweeping measures, or charge distributions, to a prescribed density, and it is closely related to (construction ... More
Magnon-driven quantum-dot heat engineJun 06 2012Jul 18 2012We investigate a heat- to charge-current converter consisting of a single-level quantum dot coupled to two ferromagnetic metals and one ferromagnetic insulator held at different temperatures. We demonstrate that this nano engine can act as an optimal ... More
Aharonov-Bohm interferometry with quantum dots: scattering approach versus tunneling pictureDec 20 2002May 16 2003We address the question of how to model electron transport through closed Aharonov-Bohm interferometers which contain quantum dots. By explicitly studying interferometers with one and two quantum dots, we establish the connection between a tunneling-Hamiltonian ... More
Global Range Estimates for Maximal Oscillatory Integrals with Radial TestfunctionsMar 24 2011We consider the maximal function of oscillatory integrals and prove a global estimate for radial test functions which is almost sharp with respect to the Sobolev regularity.
Shellability and Regularity of Chain Complexes over a Principal RingDec 20 2011Oct 17 2012The goal of this paper is to generalize some of the existing toolkit of combinatorial algebraic topology in order to study the homology of abstract chain complexes. We define shellability of chain complexes in a similar way as for cell complexes and introduce ... More
Comparing Approaches to Treatment Effect Estimation for Subgroups in Clinical TrialsMar 10 2016Jun 27 2016Identifying subgroups, which respond differently to a treatment, both in terms of efficacy and safety, is an important part of drug development. A well-known challenge in exploratory subgroup analyses is the small sample size in the considered subgroups, ... More
Coexistence of bounded and degenerate geometrySep 14 2016Sep 25 2016Almost all topological conjugacy classes of infinitely renormalizable analytic Lorenz maps of stationary monotone type contains both maps whose attractor has bounded geometry and maps whose attractor has degenerate geometry. This simultaneous appearance ... More
Sweeping Preconditioner for the Helmholtz Equation: Moving Perfectly Matched LayersJul 25 2010Aug 02 2010This paper introduces a new sweeping preconditioner for the iterative solution of the variable coefficient Helmholtz equation in two and three dimensions. The algorithms follow the general structure of constructing an approximate $LDL^t$ factorization ... More
Sweeping Preconditioner for the Helmholtz Equation: Hierarchical Matrix RepresentationJul 25 2010Aug 02 2010The paper introduces the sweeping preconditioner, which is highly efficient for iterative solutions of the variable coefficient Helmholtz equation including very high frequency problems. The first central idea of this novel approach is to construct an ... More
On Kazhdan's Property (T) for the special linear group of holomorphic functionsFeb 29 2012We investigate when the group $SL_n(\mathcal{O}(X))$ of holomorphic maps from a Stein space $X$ to $SL_n (\C)$ has Kazhdan's property (T) for $n\ge 3$. This provides a new class of examples of non-locally compact groups having Kazhdan's property (T). ... More
Experimental and cosmological constraints on heavy neutrinosFeb 02 2015Jun 02 2016We study experimental and cosmological constraints on the extension of the Standard Model by three right handed neutrinos with masses between those of the pion and W boson. We combine indirect experimental constraints from neutrino oscillation data, neutrinoless ... More
Slow Roll during the Waterfall Regime: The Small Coupling Window for SUSY Hybrid InflationApr 16 2012Jun 25 2012It has recently been pointed out that a substantial amount of e-folds can occur during the waterfall regime of hybrid inflation. Moreover, Kodama et.al. have derived analytic approximations for the trajectories of the inflaton and of the waterfall fields. ... More
Modulation of Majorana-Induced Current Cross-Correlations by Quantum DotsAug 20 2012Sep 12 2013We study charge transport through a topological superconductor with a pair of Majorana end states, coupled to leads via quantum dots with resonant levels. The non-locality of the Majorana bound states opens the possibility of crossed Andreev reflection ... More
Topological superconductivity in Quantum Hall-superconductor hybrid systemsAug 26 2014We develop a scenario to engineer a topological phase with Majorana edge states based on an integer quantum Hall (QH) system proximity coupled to a superconductor (SC). Due to the vortices in the SC order parameter, the SC - QH hybrid system is described ... More
Cross bispectra and trispectra of the non-linear integrated Sachs-Wolfe effect and the tracer galaxy density fieldOct 28 2012In order to investigate possibilities to measure non-Gaussian signatures of the non-linear iSW effect, we study in this work the family of mixed bispectra <tau^q gamma^(3-q)> and trispectra <tau^q gamma^(4-q)> between the integrated Sachs-Wolfe (iSW) ... More
On the exponential transform of multi-sheeted algebraic domainsJan 04 2011We introduce multi-sheeted versions of algebraic domains and quadrature domains, allowing them to be branched covering surfaces over the Riemann sphere. The two classes of domains turn out to be the same, and the main result states that the extended exponential ... More
On the exponential transform of lemniscatesJan 04 2011It is known that the exponential transform of a quadrature domain is a rational function for which the denominator has a certain separable form. In the present paper we show that the exponential transform of lemniscate domains in general are not rational ... More
A Perron-Frobenius type result for integer maps and applicationsSep 06 2016It is shown that for certain maps, including concave maps, on the $d$-dimensional lattice of positive integers points, `approximate' eigenvectors can be found. Applications in epidemiology as well as distributed resource allocation are discussed as examples. ... More
On the Jacobian of the harmonic moment mapMar 20 2009In this paper we represent harmonic moments in the language of transfinite functions, that is projective limits of polynomials in infinitely many variables. We obtain also an explicit formula for the Jacobian of a generalized harmonic moment map.
G2 gauge theoriesOct 30 2012QCD can be formulated using any gauge group. One particular interesting choice is to replace SU(3) by the exceptional group G2. Conceptually, this group is the simplest group with a trivial center. It thus permits to study the conjectured relevance of ... More
Sharp capacity estimates for annuli in weighted R^n and in metric spacesDec 05 2013We obtain estimates for the nonlinear variational capacity of annuli in weighted R^n and in metric spaces. We introduce four different (pointwise) exponent sets, show that they all play fundamental roles for capacity estimates, and also demonstrate that ... More
Regularity of $p(\cdot)$-superharmonic functions, the Kellogg property and semiregular boundary pointsFeb 01 2013We study various boundary and inner regularity questions for $p(\cdot)$-(super)harmonic functions in Euclidean domains. In particular, we prove the Kellogg property and introduce a classification of boundary points for $p(\cdot)$-harmonic functions into ... More
Sobolev spaces, fine gradients and quasicontinuity on quasiopen setsApr 30 2015We study different definitions of Sobolev spaces on quasiopen sets in a complete metric space equipped with a doubling measure supporting a p-Poincar\'e inequality with 1<p<\infty, and connect them to the Sobolev theory in R^n. In particular, we show ... More
First-principles study of configurational disorder in B$_{4}$C using a superatom-special quasirandom structure methodAug 31 2015Configurationally disordered crystalline boron carbide, B$_{4}$C, is studied using first-principles calculations. We investigate both dilute and high concentrations of carbon-boron substitutional defects. For the latter purpose, we suggest a superatom's ... More
Effects of configurational disorder on adatom mobilities on TiAlN(001) surfacesFeb 25 2012We use metastable NaCl-structure Ti0.5Al0.5N alloys to probe effects of configurational disorder on adatom surface diffusion dynamics which control phase stability and nanostructural evolution during film growth. First-principles calculations were employed ... More
Z2 phase diagram of three-dimensional disordered topological insulator via scattering matrix approachJan 29 2014Mar 26 2014The role of disorder in the field of three-dimensional time reversal invariant topological insulators has become an active field of research recently. However, the computation of Z2 invariants for large, disordered systems still poses a considerable challenge. ... More
Critical behavior of the Random-Field Ising model at and beyond the Upper Critical DimensionOct 14 2010Oct 19 2010The disorder-driven phase transition of the RFIM is observed using exact ground-state computer simulations for hyper cubic lattices in d=5,6,7 dimensions. Finite-size scaling analyses are used to calculate the critical point and the critical exponents ... More
openXBOW - Introducing the Passau Open-Source Crossmodal Bag-of-Words ToolkitMay 22 2016We introduce openXBOW, an open-source toolkit for the generation of bag-of-words (BoW) representations from multimodal input. In the BoW principle, word histograms were first used as features in document classification, but the idea was and can easily ... More
Complexity of the laminar-turbulent boundary in pipe flowFeb 06 2018Over the past decade, the edge of chaos has proven to be a fruitful starting point for investigations of shear flows when the laminar base flow is linearly stable. Numerous computational studies of shear flows demonstrated the existence of states that ... More
Boundary regularity for degenerate and singular parabolic equationsOct 25 2013We characterise regular boundary points of the parabolic $p$-Laplacian in terms of a family of barriers, both when $p>2$ and $1<p<2$. Due to the fact that $p\not=2$, it turns out that one can multiply the $p$-Laplace operator by a positive constant, without ... More
Improving Study Skills using Program Integrating Reflection SeminarsAug 01 2016If students have a broad spectrum of study skills, learning will likely be positively affected, since they can adapt the way they learn in different situations. Such study skills can be learned in for example learning-to-learn courses. Several studies ... More
Estimating Maximum Error Impact in Dynamic Data-driven Applications for Resource-aware Adaption of Software-based Fault-ToleranceAug 22 2016The rise of transient faults in modern hardware requires system designers to consider errors occurring at runtime. Both hardware- and software-based error handling must be deployed to meet application reliability requirements. The level of required reliability ... More
Quantum-fluctuation effects on the thermopower of a single-electron transistorFeb 27 2006Sep 18 2006We study thermal conductance and thermopower of a metallic single-electron transistor beyond the limit of weak tunnel coupling. Employing both a systematic second-order perturbation expansion and a non-perturbative approximation scheme, we find, in addition ... More