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Results for "Henk A. Dijkstra"

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On the state dependency of fast feedback processes in (palaeo) climate sensitivityMar 21 2014Apr 30 2014Palaeo data have been frequently used to determine the equilibrium (Charney) climate sensitivity $S^a$, and - if slow feedback processes (e.g. land ice-albedo) are adequately taken into account - they indicate a similar range as estimates based on instrumental ... More
Resonances in a Chaotic Attractor Crisis of the Lorenz FlowMay 23 2017Local bifurcations of stationary points and limit cycles have successfully been characterized in terms of the critical exponents of these solutions. Lyapunov exponents and their associated covariant Lyapunov vectors have been proposed as tools for supporting ... More
A Climate Network Based Stability Index for El Niño VariabilityMar 18 2015Most of the existing prediction methods gave a false alarm regarding the El Ni\~no event in 2014. A crucial aspect is currently limiting the success of such predictions, i.e. the stability of the slowly varying Pacific climate. This property determines ... More
The sensitivity and stability of the ocean's thermohaline circulation to finite amplitude perturbationsFeb 10 2007Within a simple model context, the sensitivity and stability of the thermohaline circulation to finite amplitude perturbations is studied. A new approach is used to tackle this nonlinear problem. The method is based on the computation of the so-called ... More
Deep ocean early warning signals of an Atlantic MOC collapseMay 06 2014The Atlantic Meridional Overturning Circulation (MOC) is a crucial part of the climate system because of its associated northward heat transport. The present-day MOC is sensitive to freshwater anomalies and may collapse to a state with a strongly reduced ... More
Crisis of the Chaotic Attractor of a Climate Model: A Transfer Operator ApproachJul 08 2015Dec 13 2017The destruction of a chaotic attractor leading to rough changes in the dynamics of a dynamical system is studied. Local bifurcations are characterised by a single or a pair of characteristic exponents crossing the imaginary axis. The approach of such ... More
Crisis of the Chaotic Attractor of a Climate Model: A Transfer Operator ApproachJul 08 2015The destruction of a chaotic attractor leading to a rough change in the dynamics of a system as a control parameter is smoothly varied is studied. While bifurcations involving non-chaotic invariant sets, such as fixed points or periodic orbits, can be ... More
An early warning indicator for atmospheric blocking events using transfer operatorsFeb 03 2015Mar 14 2015The existence of persistent midlatitude atmospheric flow regimes with time-scales larger than 5-10 days and indications of preferred transitions between them motivates to develop early warning indicators for such regime transitions. In this paper, we ... More
Quasi-local conserved charges in General RelativityAug 20 2019A general prescription for constructing quasi-local conserved quantities in General Relativity is proposed. The construction is applied to BMS symmetry generators in Newman-Unti gauge, so as to define quasi-local BMS charges. It is argued that the zero ... More
Gravitational memory in the bulkAug 20 2019A method for detecting gravitational memory is proposed. It makes use of ingoing null geodesics instead of timelike geodesics in the original formulation by Christodoulou. It is argued that the method is applicable in the bulk of a spacetime. In addition, ... More
On volume preserving almost Anosov flowsAug 15 2019The purpose of this paper is to establish limit laws for volume preserving almost Anosov flows on $3$-three manifolds having a neutral periodic of cubic saddle type. In the process, we derive estimates for the Dulac maps for cubic neutral saddles in planar ... More
Large time-dependent coercivity and resistivity modification under sustained voltage application in a Pt/Co/AlOx/Pt junctionOct 29 2014The coercivity and resistivity of a Pt/Co/AlOx/Pt junction are measured under sustained voltage application. High bias voltages of either polarity are determined to cause a strongly enhanced, reversible coercivity modification compared to low voltages. ... More
Water ice growth around evolved starsJan 29 2003We present a model of the growth of water ice on silicate grains in the circumstellar envelopes of Asymptotic Giant Branch (AGB) stars and Red Super Giants. We consider the growth of ice by gas grain collisions, the thermal evaporation of ice from a grain, ... More
Heterofusion: Fusing genomics data of different measurement scalesApr 23 2019In systems biology, it is becoming increasingly common to measure biochemical entities at different levels of the same biological system. Hence, data fusion problems are abundant in the life sciences. With the availability of a multitude of measuring ... More
Anomalous direction for skyrmion bubble motionJul 19 2018Magnetic skyrmions are localized topological excitations that behave as particles and can be mobile, with great potential for novel data storage devices. In this work, the current-induced dynamics of large skyrmion bubbles is studied. When skyrmion motion ... More
Effects of Drake Passage on a strongly eddying global oceanOct 14 2015The climate impact of ocean gateway openings during the Eocene-Oligocene transition is still under debate. Previous model studies employed grid resolutions at which the impact of mesoscale eddies has to be parameterized. We present results of a state-of-the-art ... More
Derivation of Delay Equation Climate Models Using the Mori-Zwanzig FormalismFeb 08 2019Models incorporating delay have been frequently used to understand climate variability phenomena, but often the delay is introduced through an ad-hoc physical reasoning, such as the propagation time of waves. In this paper, the Mori-Zwanzig formalism ... More
Derivation of Delay Equation Climate Models Using the Mori-Zwanzig FormalismFeb 08 2019May 17 2019Models incorporating delay have been frequently used to understand climate variability phenomena, but often the delay is introduced through an ad-hoc physical reasoning, such as the propagation time of waves. In this paper, the Mori-Zwanzig formalism ... More
Mixing Spectrum in Reduced Phase Spaces of Stochastic Differential Equations. Part II: Stochastic Hopf BifurcationMay 22 2017The spectrum of the Markov semigroup of a diffusion process, referred to as the mixing spectrum, provides a detailed characterization of the dynamics of statistics such as the correlation function and the power spectrum. Stochastic analysis techniques ... More
Using Network Theory and Machine Learning to predict El NiñoMar 27 2018Aug 10 2018The skill of current predictions of the warm phase of the El Ni\~no Southern Oscillation (ENSO) reduces significantly beyond a lag of six months. In this paper, we aim to increase this prediction skill at lags up to one year. The new method to do so combines ... More
Restricted Successive MinimaFeb 06 2013Mar 13 2013We give bounds on the successive minima of an $o$-symmetric convex body under the restriction that the lattice points realizing the successive minima are not contained in a collection of forbidden sublattices. Our investigations extend former results ... More
Foundations of Descriptive and Inferential StatisticsFeb 11 2013Aug 30 2015These lecture notes were written with the aim to provide an accessible though technically solid introduction to the logic of systematical analyses of statistical data to undergraduate and to postgraduate students, in particular in the Social Sciences ... More
Altmetrics as traces of the computerization of the research processOct 17 2015I propose a broad, multi-dimensional conception of altmetrics, namely as traces of the computerization of the research process. Computerization should be conceived in its broadest sense, including all recent developments in ICT and software, taking place ... More
Fibonacci-like unimodal inverse limit spaces and the core Ingram conjectureMay 20 2013We study the structure of inverse limit space of so-called Fibonacci-like tent maps. The combinatorial constraints implied by the Fibonacci-like assumption allow us to introduce certain chains that enable a more detailed analysis of symmetric arcs within ... More
Note on adelic triangulations and an Adelic Blichfeldt-type inequalityMay 22 2014We introduce a notion of convex hull and polytope into adele space. This allows to consider adelic triangulations which, in particular, lead to an adelic blichfeldt-type inequality, complementing former results.
Iran's scientific dominance and the emergence of South-East Asian countries as scientific collaborators in the Persian Gulf RegionFeb 15 2016Apr 04 2016A longitudinal bibliometric analysis of publications indexed in Thomson Reuters' Incites and Elsevier's Scopus, and published from Persian Gulf States and neighbouring Middle East countries, shows clear effects of major political events during the past ... More
An Introduction to Business MathematicsSep 11 2015Sep 16 2015These lecture notes provide a self-contained introduction to the mathematical methods required in a Bachelor degree programme in Business, Economics, or Management. In particular, the topics covered comprise real-valued vector and matrix algebra, systems ... More
Determination of the positions and orientations of concentrated rod-like colloids from 3D microscopy dataJun 19 2014Confocal microscopy in combination with real-space particle tracking has proven to be a powerful tool in scientific fields such as soft matter physics, materials science and cell biology. However, 3D tracking of anisotropic particles in concentrated phases ... More
Privacy Design StrategiesOct 24 2012May 06 2013In this paper we define the notion of a privacy design strategy. These strategies help IT architects to support privacy by design early in the software development life cycle, during concept development and analysis. Using current data protection legislation ... More
Bias-voltage dependence of the magneto-resistance in ballistic vacuum tunneling: Theory and application to planar Co(0001) junctionsMay 22 2003Motivated by first-principles results for jellium and by surface-barrier shapes that are typically used in electron spectroscopies, the bias voltage in ballistic vacuum tunneling is treated in a heuristic manner. The presented approach leads in particular ... More
Distributed Double Spending PreventionFeb 06 2008We study the problem of preventing double spending in electronic payment schemes in a distributed fashion. This problem occurs, for instance, when the spending of electronic coins needs to be controlled by a large collection of nodes (eg. in a peer-to-peer ... More
In Things We Trust? Towards trustability in the Internet of ThingsSep 12 2011This essay discusses the main privacy, security and trustability issues with the Internet of Things.
The Ephemeral Pairing ProblemFeb 06 2008In wireless ad-hoc broadcast networks the pairing problem consists of establishing a (long-term) connection between two specific physical nodes in the network that do not yet know each other. We focus on the ephemeral version of this problem. Ephemeral ... More
Self-stabilizing mutual exclusion on a ring, even if K=NSep 21 1999We show that, contrary to common belief, Dijkstra's self-stabilizing mutual exclusion algorithm on a ring [Dij74,Dij82] also stabilizes when the number of states per node is one less than the number of nodes on the ring.
Integer Knapsacks: Average Behavior of the Frobenius NumbersOct 01 2008The main result of the paper shows that the asymptotic growth of the Frobenius number in average is significantly slower than the growth of the maximum Frobenius number.
On Feasibility of Integer KnapsacksNov 21 2009Given an integer mxn matrix A satisfying certain regularity assumptions, we consider the set F(A) of all integer vectors b such that the associated knapsack polytope P(A,b)={x: Ax=b, x>=0} contains an integer point. When m=1 the set F(A) is known to contain ... More
Dynamic Transitions of Surface Tension Driven ConvectionMay 05 2011We study the well-posedness and dynamic transitions of the surface tension driven convection in a three-dimensional (3D) rectangular box with non-deformable upper surface and with free-slip boundary conditions. It is shown that as the Marangoni number ... More
Acceleration of Galactic Supershells by Lyman Alpha RadiationSep 11 2008Feb 25 2009Scattering of Lyman Alpha (hereafter Lya) photons by neutral hydrogen gas in a single outflowing 'supershell' around star forming regions often explains the shape and offset of the observed Lya emission line from galaxies. We compute the radiation pressure ... More
Effect of bond length fluctuations on crystal nucleation of hard bead chainsApr 24 2012Jun 26 2012We study the spontaneous nucleation and crystallization of linear and cyclic chains of flexibly connected hard spheres using extensive molecular dynamics simulations. To this end, we present a novel event-driven molecular dynamics simulation method, which ... More
Lyman Alpha Driven Outflows Around Star Forming GalaxiesJul 16 2008Sep 11 2008We present accurate Monte-Carlo calculations of Lyman Alpha (hereafter Lya) radiation pressure in a range of models which represent galaxies during various epochs of our Universe. We show that the radiation force that Lya photons exert on hydrogen gas ... More
On a discrete John-type theoremApr 10 2019As a discrete counterpart to the classical John theorem on the approximation of (symmetric) $n$-dimensional convex bodies $K$ by ellipsoids, Tao and Vu introduced so called generalized arithmetic progressions $P(A,b)\subset Z^n$ in order to cover (many ... More
Factorization, majorization, and domination for linear relationsNov 21 2014Let ${\mathfrak H}_A$, ${\mathfrak H}_B$, and ${\mathfrak H}$ be Hilbert spaces. Let $A$ be a linear relation from ${\mathfrak H}$ to ${\mathfrak H}_A$ and let $B$ be a linear relation from ${\mathfrak H}$ to ${\mathfrak H}_B$. If there exists an operator ... More
Practical Schemes For Privacy & Security Enhanced RFIDSep 07 2009Feb 25 2010Proper privacy protection in RFID systems is important. However, many of the schemes known are impractical, either because they use hash functions instead of the more hardware efficient symmetric encryption schemes as a efficient cryptographic primitive, ... More
Increased security through open sourceJan 25 2008In this paper we discuss the impact of open source on both the security and transparency of a software system. We focus on the more technical aspects of this issue, combining and extending arguments developed over the years. We stress that our discussion ... More
Scanning electron microscopy with polarization analysis for multilayered chiral spin texturesAug 01 2017We show that scanning electron microscopy with polarization analysis (SEMPA) that is sensitive to both in-plane magnetization components can be used to image the out-of-plane magnetized multi-domain state in multilayered chiral spin textures. By depositing ... More
Enhanced direct collapse due to Lyman alpha feedbackNov 02 2016Feb 27 2017We assess the impact of trapped Lyman alpha cooling radiation on the formation of direct collapse black holes (DCBHs). We apply a one-zone chemical and thermal evolution model, accounting for the photodetachment of H- ions, precursors to the key coolant ... More
Tuning magnetic chirality by dipolar interactionsApr 03 2019Chiral magnetism has gained enormous interest in recent years because of the anticipated wealth of applications in nanoelectronics. The demonstrated stabilization of chiral magnetic domain walls and skyrmions has been attributed to the actively investigated ... More
Dynamic Transitions of Quasi-Geostrophic Channel FlowFeb 11 2015The main aim of this paper is to describe the dynamic transitions in flows described by the two-dimensional, barotropic vorticity equation in a periodic zonal channel. In \cite{CGSW03}, the existence of a Hopf bifurcation in this model as the Reynolds ... More
Intrinsic unpredictability of strong El Niño eventsJul 09 2016The El Ni\~no-Southern Oscillation (ENSO) is a mode of interannual variability in the coupled equatorial ocean/atmosphere Pacific. El Ni\~no describes a state in which sea surface temperatures in the eastern Pacific increase and upwelling of colder, deep ... More
(Un)predictability of strong El Niño eventsOct 09 2017The El Ni\~no-Southern Oscillation (ENSO) is a mode of interannual variability in the coupled equatorial Pacific coupled atmosphere/ocean system. El Ni\~no describes a state in which sea surface temperatures in the eastern Pacific increase and upwelling ... More
High-Performance Distributed Multi-Model / Multi-Kernel Simulations: A Case-Study in Jungle ComputingMar 01 2012High-performance scientific applications require more and more compute power. The concurrent use of multiple distributed compute resources is vital for making scientific progress. The resulting distributed system, a so-called Jungle Computing System, ... More
Unified functional network and nonlinear time series analysis for complex systems science: The pyunicorn packageJul 02 2015Apr 06 2016We introduce the \texttt{pyunicorn} (Pythonic unified complex network and recurrence analysis toolbox) open source software package for applying and combining modern methods of data analysis and modeling from complex network theory and nonlinear time ... More
Distances to Lattice Points in Knapsack PolyhedraMay 11 2018We give an optimal upper bound for the maximum-norm distance from a vertex of a knapsack polyhedron to its nearest feasible lattice point. In a randomised setting, we show that the upper bound can be significantly improved on average. As a corollary, ... More
MIMO with More Users than RF ChainsSep 15 2017Antenna arrays with hybrid analog-digital signal processing capabilities offer a compromise between the performance of digital arrays and the cost-efficiency of analog arrays with a single radio-frequency (RF) chain. A limitation of hybrid arrays is that ... More
A Precipice Below Which Lies Absurdity? Theories without a Spacetime and Scientific UnderstandingJul 07 2018While the relation between visualization and scientific understanding has been a topic of long-standing discussion, recent developments in physics have pushed the boundaries of this debate to new and still unexplored realms. For it is claimed that, in ... More
Truncated moment problems in the class of generalized Nevanlinna functionsDec 30 2010Truncated moment problems in the class of generalized Nevanlinna functions are investigated. General solvability criteria will be established, covering both the even and odd problems, including complete parametrizations of solutions. The main new results ... More
Fundamental Limits of Wideband Localization - Part II: Cooperative NetworksJun 04 2010The availability of positional information is of great importance in many commercial, governmental, and military applications. Localization is commonly accomplished through the use of radio communication between mobile devices (agents) and fixed infrastructure ... More
Specific heat of the simple-cubic Ising modelDec 08 2009We provide an expression quantitatively describing the specific heat of the Ising model on the simple-cubic lattice in the critical region. This expression is based on finite-size scaling of numerical results obtained by means of a Monte Carlo method. ... More
Semi-passivity and synchronization of diffusively coupled neuronal oscillatorsMar 20 2009We discuss synchronization in networks of neuronal oscillators which are interconnected via diffusive coupling, i.e. linearly coupled via gap junctions. In particular, we present sufficient conditions for synchronization in these networks using the theory ... More
Existence and convergence properties of physical measures for certain dynamical systems with holesMay 29 2007Sep 24 2008We study two classes of dynamical systems with holes: expanding maps of the interval and Collet-Eckmann maps with singularities. In both cases, we prove that there is a natural absolutely continuous conditionally invariant measure $\mu$ (a.c.c.i.m.) with ... More
Finite-size Scaling and Universality above the Upper Critical DimensionalityJan 26 1996According to renormalization theory, Ising systems above their upper critical dimensionality d_u = 4 have classical critical behavior and the ratio of magnetization moments Q = <m^2>^2 / <m^4> has the universal value 0.456947... However, Monte Carlo simulations ... More
The relation between stellar mass and weak lensing signal around galaxies: Implications for MONDOct 16 2008We study the amplitude of the weak gravitational lensing signal as a function of stellar mass around a sample of relatively isolated galaxies. This selection of lenses simplifies the interpretation of the observations, which consist of data from the Red- ... More
Goldstone modes in Lyapunov spectra of hard sphere systemsDec 20 2003Apr 29 2004In this paper, we demonstrate how the Lyapunov exponents close to zero of a system of many hard spheres can be described as Goldstone modes, by using a Boltzmann type of approach. At low densities, the correct form is found for the wave number dependence ... More
The boundary between long-range and short-range critical behaviorDec 27 2001We investigate phase transitions of two-dimensional Ising models with power-law interactions, using an efficient Monte Carlo algorithm. For slow decay, the transition is of the mean-field type; for fast decay, it belongs to the short-range Ising universality ... More
The Identity Crisis. Security, Privacy and Usability Issues in Identity ManagementJan 02 2011This paper studies the current "identity crisis" caused by the substantial security, privacy and usability shortcomings encountered in existing systems for identity management. Some of these issues are well known, while others are much less understood. ... More
Space-Efficient Routing Tables for Almost All Networks and the Incompressibility MethodMar 10 1999We use the incompressibility method based on Kolmogorov complexity to determine the total number of bits of routing information for almost all network topologies. In most models for routing, for almost all labeled graphs $\Theta (n^2)$ bits are necessary ... More
Amplitude and Frequency Spectrum of Thermal Fluctuations of A Translocating RNA MoleculeJan 25 2008Aug 03 2009Using a combination of theory and computer simulations, we study the translocation of an RNA molecule, pulled through a solid-state nanopore by an optical tweezer, as a method to determine its secondary structure. The resolution with which the elements ... More
Uncountably many planar embeddings of unimodal inverse limit spacesMar 12 2016Sep 08 2016For point $x$ in the inverse limit space $X$ with a single unimodal bonding map we construct, with the use of symbolic dynamics, a planar embedding such that $x$ is accessible. It follows that there are uncountably many non-equivalent planar embeddings ... More
The Core Ingram Conjecture for non-recurrent critical pointsDec 22 2015We study inverse limit spaces of tent maps, and the Ingram Conjecture, which states that the inverse limit spaces of tent maps with different slopes are non-homeomorphic. When the tent map is restricted to its core, so there is no ray compactifying on ... More
Expected Frobenius numbersOct 14 2009We show that for large instances the order of magnitude of the expected Frobenius number is (up to a constant depending only on the dimension) given by its lower bound.
Industrial Symbiotic Networks as Coordinated GamesApr 19 2018We present an approach for implementing a specific form of collaborative industrial practices-called Industrial Symbiotic Networks (ISNs)-as MC-Net cooperative games and address the so called ISN implementation problem. This is, the characteristics of ... More
Phase behavior and structure of model colloid-polymer mixtures confined between two parallel planar wallsMar 28 2006Using Gibbs ensemble Monte Carlo simulations and density functional theory we investigate the fluid-fluid demixing transition in inhomogeneous colloid-polymer mixtures confined between two parallel plates with separation distances between one and ten ... More
Beyond Lyman-alpha: Constraints and Consistency Tests from the Lyman-beta ForestMay 27 2003Feb 26 2004Absorption between the rest-frame wavelengths of 973 and 1026 Angstroms in quasar spectra arises from two sources (apart from occasional metals): one is due to Lyman-alpha (Lya) absorption by materials at a low redshift, and the other from Lyman-beta ... More
The Impact of The IGM on High-Redshift Lyman Alpha Emission LinesJan 23 2007May 04 2007We calculate the impact of the intergalactic medium (IGM) on the observed Lyman alpha lines (hereafter Lya) emitted by galaxies in an ionised IGM at z>4. Our model accounts for gas clumping in the IGM and for the fact that high-redshift galaxies reside ... More
Fabrication of colloidal Laves phases via hard tetramers and hard spheres: bulk phase diagram and sedimentation behaviourMar 24 2016Feb 08 2017Colloidal photonic crystals display peculiar optical properties which make them particularly suitable for application in different fields. However, the low packing fraction of the targeted structures usually poses a real challenge in the fabrication stage. ... More
Stabilizing the Hexagonal Close Packed Structure of Hard Spheres with Polymers : Phase diagram, Structure, and DynamicsMay 02 2016We study the phase behaviour of a binary mixture of colloidal hard spheres and freely-jointed chains of beads using Monte Carlo simulations. Recently Panagiotopoulos and coworkers predicted [Nat. Commun. 5, 4472 (2014)] that the hexagonal close packed ... More
Non-trivial topological valence bands of common diamond and zinc-blende semiconductorsApr 10 2019The diamond and zinc-blende semiconductors are well-known and have been widely studied for decades. Yet, their electronic structure still surprises with unexpected topological properties of the valence bands. In this joint theoretical and experimental ... More
Asymptotic isotropization in inhomogeneous cosmologyJun 26 2003In this paper we investigate asymptotic isotropization. We derive the asymptotic dynamics of spatially inhomogeneous cosmological models with a perfect fluid matter source and a positive cosmological constant near the de Sitter equilibrium state at late ... More
Boundary relations and generalized resolvents of symmetric operatorsOct 09 2006The Kre\u{\i}n-Naimark formula provides a parametrization of all selfadjoint exit space extensions of a, not necessarily densely defined, symmetric operator, in terms of maximal dissipative (in $\dC_+$) holomorphic linear relations on the parameter space ... More
Sandpile groups of generalized de Bruijn and Kautz graphs and circulant matrices over finite fieldsMay 01 2014A maximal minor $M$ of the Laplacian of an $n$-vertex Eulerian digraph $\Gamma$ gives rise to a finite group $\mathbb{Z}^{n-1}/\mathbb{Z}^{n-1}M$ known as the sandpile (or critical) group $S(\Gamma)$ of $\Gamma$. We determine $S(\Gamma)$ of the generalized ... More
Adaptive Observers and Parameter Estimation for a Class of Systems Nonlinear in the ParametersMar 13 2009Jun 21 2013We consider the problem of asymptotic reconstruction of the state and parameter values in systems of ordinary differential equations. A solution to this problem is proposed for a class of systems of which the unknowns are allowed to be nonlinearly parameterized ... More
On the chaotic behavior of the Primal--Dual Affine--Scaling Algorithm for Linear OptimizationSep 22 2014Sep 23 2014We study a one-parameter family of quadratic maps, which serves as a template for interior point methods. It is known that such methods can exhibit chaotic behavior, but this has been verified only for particular linear optimization problems. Our results ... More
The Grism Lens-Amplified Survey from Space (GLASS). I. Survey overview and first data releaseSep 01 2015Sep 04 2015We give an overview of the Grism Lens Amplified Survey from Space (GLASS), a large Hubble Space Telescope program aimed at obtaining grism spectroscopy of the fields of ten massive clusters of galaxies at redshift z=0.308-0.686, including the Hubble Frontier ... More
Ising Universality in Three Dimensions: A Monte Carlo StudySep 04 1995We investigate three Ising models on the simple cubic lattice by means of Monte Carlo methods and finite-size scaling. These models are the spin-1/2 Ising model with nearest-neighbor interactions, a spin-1/2 model with nearest-neighbor and third-neighbor ... More
Finite-size scaling above the upper critical dimension revisited: The case of the five-dimensional Ising modelJan 07 1999Monte Carlo results for the moments <M^k> of the magnetization distribution of the nearest-neighbor Ising ferromagnet in a L^d geometry, where L (4 \leq L \leq 22) is the linear dimension of a hypercubic lattice with periodic boundary conditions in d=5 ... More
Correlating transmission and local electronic structure in planar junctions: A tool for analyzing spin-dependent transport calculationsDec 22 2010We propose to correlate transmittance maps and spectral-density maps of planar junctions, in order to analyze quantitatively and in detail spin-dependent transport calculations. Since spectral-density maps can be resolved with respect to atom, angular ... More
All Abelian Quotient C.I.-Singularities Admit Projective Crepant Resolutions in All DimensionsApr 10 1997For Gorenstein quotient spaces $C^d/G$, a direct generalization of the classical McKay correspondence in dimensions $d\geq 4$ would primarily demand the existence of projective, crepant desingularizations. Since this turned out to be not always possible, ... More
On parity check collections for iterative erasure decoding that correct all correctable erasure patterns of a given sizeJul 28 2005Recently there has been interest in the construction of small parity check sets for iterative decoding of the Hamming code with the property that each uncorrectable (or stopping) set of size three is the support of a codeword and hence uncorrectable anyway. ... More
Asymptotic silence of generic cosmological singularitiesFeb 11 2004Jan 25 2005In this letter we investigate the nature of generic cosmological singularities using the framework developed by Uggla et al. We do so by studying the past asymptotic dynamics of general vacuum G2 cosmologies, models that are expected to capture the singular ... More
Line and Plane Cover Numbers RevisitedAug 20 2019A measure for the visual complexity of a straight-line crossing-free drawing of a graph is the minimum number of lines needed to cover all vertices. For a given graph $G$, the minimum such number (over all drawings in dimension $d \in \{2,3\}$) is called ... More
Medium-range interactions and crossover to classical critical behaviorJul 03 1996We study the crossover from Ising-like to classical critical behavior as a function of the range R of interactions. The power-law dependence on R of several critical amplitudes is calculated from renormalization theory. The results confirm the predictions ... More
Field dependent collision frequency of the two-dimensional driven random Lorentz gasMay 08 2001In the field-driven, thermostatted Lorentz gas the collision frequency increases with the magnitude of the applied field due to long-time correlations. We study this effect with computer simulations and confirm the presence of non-analytic terms in the ... More
Sensitivity analysis of hybrid systems with state jumps with application to trajectory trackingJun 11 2014This paper addresses the sensitivity analysis for hybrid systems with discontinuous (jumping) state trajectories. We consider state-triggered jumps in the state evolution, potentially accompanied by mode switching in the control vector field as well. ... More
A general realization theorem for matrix-valued Herglotz-Nevanlinna functionsOct 21 2005New special types of stationary conservative impedance and scattering systems, the so-called non-canonical systems, involving triplets of Hilbert spaces and projection operators, are considered. It is established that every matrix-valued Herglotz-Nevanlinna ... More
Frustration of the isotropic-columnar phase transition of colloidal hard platelets by a transient cubatic phaseDec 06 2011Using simulations and theory, we show that the cubatic phase is metastable for three model hard platelets. The locally favored structures of perpendicular particle stacks in the fluid prevent the formation of the columnar phase through geometric frustration ... More
Blue Wings and Bumps via Fermi-like Acceleration of Lyman-alpha photons across ShocksSep 24 2015We explore the impact of Fermi-like acceleration of Lyman-alpha (Ly{\alpha}) photons across shock fronts on the observed Ly{\alpha} spectral line shape. We first confirm the result of Neufeld & McKee (1988) that this mechanism gives rise to extended blue ... More
Density Functional Theory for Chiral Nematic Liquid CrystalsApr 08 2014Even though chiral nematic phases were the first liquid crystals experimentally observed more than a century ago, the origin of the thermodynamic stability of cholesteric states is still unclear. In this Letter we address the problem by means of a novel ... More
Crystal nucleation of hard spheres using molecular dynamics, umbrella sampling and forward flux sampling: A comparison of simulation techniquesJun 15 2010Over the last number of years several simulation methods have been introduced to study rare events such as nucleation. In this paper we examine the crystal nucleation rate of hard spheres using three such numerical techniques: molecular dynamics, forward ... More
Unlocking the Full Potential of Extragalactic Ly$α$ through Its Polarization PropertiesFeb 12 2018Mar 28 2018Lyman-$\alpha$ (Ly$\alpha$) is a powerful astrophysical probe. Not only is it ubiquitous at high redshifts, it is also a resonant line, making Ly$\alpha$ photons scatter. This scattering process depends on the physical conditions of the gas through which ... More
Western Europe is warming much faster than expectedJun 04 2008Jun 06 2008The warming trend of the last decades is now so strong that it is discernible in local temperature observations. This opens the possibility to compare the trend to the warming predicted by comprehensive climate models (GCMs), which up to now could not ... More