Results for "Sabine Jansen"

total 1694took 0.14s
Cluster expansions for Gibbs point processesJul 27 2018We provide a sufficient condition for the uniqueness in distribution of Gibbs point processes with non-negative pairwise interaction, together with convergent expansions of the log-Laplace functional, factorial moment densities and factorial cumulant ... More
Cluster expansions with renormalized activities and applications to colloidsMar 05 2019We consider a binary system of small and large objects in the continuous space interacting via a non-negative potential. By integrating over the small objects, the effective interaction between the large ones becomes multi-body. We prove convergence of ... More
On the notion(s) of duality for Markov processesOct 26 2012Feb 17 2014We provide a systematic study of the notion of duality of Markov processes with respect to a function. We discuss the relation of this notion with duality with respect to a measure as studied in Markov process theory and potential theory and give functional ... More
A note on the uniqueness result for the inverse Henderson problemMar 08 2019The inverse Henderson problem of statistical mechanics concerns classical particles in continuous space which interact according to a pair potential depending on the distance of the particles. Roughly stated, it asks for the interaction potential given ... More
Singularity analysis for heavy-tailed random variablesSep 17 2015May 31 2018We propose a novel complex-analytic method for sums of i.i.d. random variables that are heavy-tailed and integer-valued. The method combines singularity analysis, Lindel\"of integrals, and bivariate saddle points. As an application, we prove three theorems ... More
Fermionic and bosonic Laughlin state on thick cylindersSep 19 2011We investigate a many-body wave function for particles on a cylinder known as Laughlin's function. It is the power of a Vandermonde determinant times a Gaussian. Our main result is: in a many-particle limit, at fixed radius, all correlation functions ... More
Continuum percolation for Gibbsian point processes with attractive interactionsAug 06 2012Aug 30 2012We study the problem of continuum percolation in infinite volume Gibbs measures for particles with an attractive pair potential, with a focus on low temperatures (large $\beta$). The main results are bounds on percolation thresholds $\rho_\pm(\beta)$ ... More
Cluster and virial expansions for the multi-species Tonks gasMar 08 2015Sep 25 2015We consider a mixture of non-overlapping rods of different lengths $\ell_k$ moving in $\mathbb{R}$ or $\mathbb{Z}$. Our main result are necessary and sufficient convergence criteria for the expansion of the pressure in terms of the activities $z_k$ and ... More
Mayer and virial series at low temperatureSep 29 2011May 18 2012We analyze the Mayer pressure-activity and virial pressure-density series for a classical system of particles in continuous configuration space at low temperature. Particles interact via a finite range potential with an attractive tail. We propose physical ... More
Graphical representation of certain moment dualities and application to population models with balancing selectionJul 25 2012Feb 21 2013We investigate dual mechanisms for interacting particle systems. Generalizing an approach of Alkemper and Hutzenthaler in the case of coalescing duals, we show that a simple linear transformation leads to a moment duality of suitably rescaled processes. ... More
Wigner crystallization in the quantum 1D jellium at all densitiesJun 28 2013Feb 03 2014The jellium is a model, introduced by Wigner (1934), for a gas of electrons moving in a uniform neutralizing background of positive charge. Wigner suggested that the repulsion between electrons might lead to a broken translational symmetry. For classical ... More
Large deviations for cluster size distributions in a continuous classical many-body systemJul 19 2011Mar 17 2015An interesting problem in statistical physics is the condensation of classical particles in droplets or clusters when the pair-interaction is given by a stable Lennard-Jones-type potential. We study two aspects of this problem. We start by deriving a ... More
Symmetry breaking in Laughlin's state on a cylinderNov 09 2007Aug 15 2008We investigate Laughlin's fractional quantum Hall effect wave function on a cylinder. We show that it displays translational symmetry breaking in the axial direction for sufficiently thin cylinders. At filling factor 1/p, the period is p times the period ... More
Bounds for the adiabatic approximation with applications to quantum computationMar 20 2006Nov 08 2007We present straightforward proofs of estimates used in the adiabatic approximation. The gap dependence is analyzed explicitly. We apply the result to interpolating Hamiltonians of interest in quantum computing.
Virial inversion and density functionalsJun 05 2019We prove a novel inversion theorem for functionals given as power series in infinite-dimensional spaces and apply it to the inversion of the density-activity relation for inhomogeneous systems. This provides a rigorous framework to prove convergence for ... More
Singularity analysis for heavy-tailed random variablesSep 17 2015Let $\alpha \in (0,1),c>0$ and $G(z) = c\sum_{k=1}^\infty z^k \exp( - k^\alpha)$. We apply complex analysis to determine the asymptotic behavior of the $m$th coefficient of the $n$th power of $G(z)$ when $m,n\to \infty$ with $m \geq n G'(1)/G(1)$ and ... More
Symmetry breaking in quasi-1D Coulomb systemsAug 22 2010Sep 21 2010Quasi one-dimensional systems are systems of particles in domains which are of infinite extent in one direction and of uniformly bounded size in all other directions, e.g. on a cylinder of infinite length. The main result proven here is that for such ... More
Random partitions in statistical mechanicsJan 07 2014Sep 11 2014We consider a family of distributions on spatial random partitions that provide a coupling between different models of interest: the ideal Bose gas; the zero-range process; particle clustering; and spatial permutations. These distributions are invariant ... More
Theory and Phenomenology of Spacetime DefectsJan 01 2014Whether or not space-time is fundamentally discrete is of central importance for the development of the theory of quantum gravity. If the fundamental description of space-time is discrete, typically represented in terms of a graph or network, then the ... More
At the Frontier of KnowledgeJan 20 2010At any time, there are areas of science where we are standing at the frontier of knowledge, and can wonder whether we have reached a fundamental limit to human understanding. What is ultimately possible in physics? I will argue here that it is ultimately ... More
AntigravitationSep 18 2009We discuss why there are no negative gravitational sources in General Relativity and show that it is possible to extend the classical theory such that repulsive gravitational interaction occurs.
Keys to Cosmology - Clusters of GalaxiesSep 05 2003We review several aspects of clusters of galaxies and their application to cosmology. We present first results of numerical simulations of the dynamics of the intra-cluster gas and of different interaction processes between cluster galaxies and the intra-cluster ... More
Large Extra Dimensions and the Minimal LengthSep 29 2004Sep 29 2004Large extra dimensions lower the Planck scale to values soon accessible. Motivated by String Theory, the models of large extra dimensions predict a vast number of new effects in the energy range of the lowered Planck scale, among them the production of ... More
Running Coupling with Minimal LengthMay 14 2004Nov 06 2004In models with large additional dimensions, the GUT scale can be lowered to values accessible by future colliders. Due to modification of the loop corrections from particles propagating into the extra dimensions, the logarithmic running of the couplings ... More
Unfactorized versus factorized calculations for ^2H(e,e'p) reactions at GeV energiesSep 27 2000Dec 11 2000In the literature, one often finds calculations of (e,e'p) reactions at GeV energies using the factorization approach. Factorization implies that the differential cross section can be written as the product of an off-shell electron-proton cross section ... More
A comparison of locally analytic group cohomology and Lie algebra cohomology for p-adic Lie groupsJan 22 2012The main result of this work is a new proof and generalization of Lazard's comparison theorem of locally analytic group cohomology with Lie algebra cohomology for K-Lie groups, where K is a finite extension of the p-adic numbers. We show the following ... More
Local convergence of spectra and pseudospectraMay 03 2016We prove local convergence results for the spectra and pseudospectra of sequences of linear operators acting in different Hilbert spaces and converging in generalised strong resolvent sense to an operator with possibly non-empty essential spectrum. We ... More
Schrödinger operator with non-zero accumulation points of complex eigenvaluesMay 30 2016We study Schr\"odinger operators $H=-\Delta+V$ in $L^2(\Omega)$ where $\Omega$ is $\mathbb R^d$ or the half-space $\mathbb R_+^d$, subject to (real) Robin boundary conditions in the latter case. For $p>d$ we construct a non-real potential $V\in L^p(\Omega)\cap ... More
Cosmological Phase transitions from Lattice Field TheoryNov 22 2011In this proceedings contribution we discuss the fate of the electroweak and the quantum chromodynamics phase transitions relevant for the early stage of the universe at non-zero temperature. These phase transitions are related to the Higgs mechanism and ... More
Chiral Fermions, Anomalies and Chern-Simons Currents on the LatticeDec 21 1992I discuss the zeromode spectrum of lattice chiral fermions in the domain wall model suggested recently. In particular I give the critical momenta where the fermions cease to be chiral and show that the spectrum is directly related to the behaviour of ... More
Surface energy and boundary layers for a chain of atoms at low temperatureApr 12 2019We analyze the surface energy and boundary layers for a chain of atoms at low temperature for an interaction potential of Lennard-Jones type. The pressure (stress) is assumed small but positive and bounded away from zero, while the temperature $\beta^{-1}$ ... More
The Widom-Rowlinson model: Mesoscopic fluctuations for the critical dropletJun 30 2019Jul 02 2019We study the critical droplet for a close-to-equilibrium Widom-Rowlinson model of interacting particles in the two-dimensional continuum at low temperatures. The critical droplet is the set of macroscopic states that correspond to saddle points for the ... More
Multispecies Virial ExpansionsApr 08 2013Jun 11 2013We study the virial expansion of mixtures of countably many different types of particles. The main tool is the Lagrange-Good inversion formula, which has other applications such as counting coloured trees or studying probability generating functions in ... More
Overlap and domain wall fermions: what is the price of chirality?Nov 30 2001In this contribution the costs of simulations employing domain wall and overlap fermions are estimated. In the discussion we will stay within the quenched approximation.
Weakening Assumptions for Deterministic Subexponential Time Non-Singular Matrix CompletionOct 08 2009In (Kabanets, Impagliazzo, 2004) it is shown how to decide the circuit polynomial identity testing problem (CPIT) in deterministic subexponential time, assuming hardness of some explicit multilinear polynomial family for arithmetical circuits. In this ... More
Non-equispaced B-spline waveletsFeb 05 2015Oct 19 2016This paper has three main contributions. The first is the construction of wavelet transforms from B-spline scaling functions defined on a grid of non-equispaced knots. The new construction extends the equispaced, biorthogonal, compactly supported Cohen-Daubechies-Feauveau ... More
The Finite Temperature Phase Diagram of a U(1) Higgs-Yukawa ModelSep 01 1992The finite temperature phase diagram of a U(1) Higgs-Yukawa model at a finite value of the scalar self coupling $\lambda$ is investigated by means of a large-$N_f$ calculation and numerical simulations. The phase diagram is similar to the one at zero ... More
Chiral Fermions and Anomalies on a Finite LatticeJun 10 1992A recent proposal by Kaplan for a chiral gauge theory on the lattice is tested with background gauge fields. The spectrum of the finite lattice Hamiltonian is calculated and the existence of a chiral fermion is demonstrated. Lattice doublers are found ... More
Status Report on ILDG activitiesSep 07 2006Oct 05 2006A status report about the International Lattice Data Grid (ILDG) is given. Different countries participating in the ILDG have created regional lattice data grid solutions that are implemented, working and used. The remaining task and the focus of present ... More
Enron versus EUSES: A Comparison of Two Spreadsheet CorporaMar 13 2015Spreadsheets are widely used within companies and often form the basis for business decisions. Numerous cases are known where incorrect information in spreadsheets has lead to incorrect decisions. Such cases underline the relevance of research on the ... More
Domain Wall Fermions and Chiral Gauge TheoriesOct 26 1994We review the status of the domain wall fermion approach to construct chiral gauge theories on the lattice. In this model an extra, fifth dimension is added and our 4-dimensional world lives on a domainwall induced by a soliton shaped mass defect that ... More
Recent Developments in Fermion Simulation AlgorithmsJul 23 1996A summary of recent developments in the field of simulation algorithms for dynamical fermions is given.
Actions for dynamical fermion simulations: are we ready to go?Nov 26 2003A critical review, playing devil's advocate, on present dynamical fermion simulations is given.
Overdamped modes in Schwarzschild-de Sitter and a Mathematica package for the numerical computation of quasinormal modesSep 26 2017Nov 17 2017We present a package for Mathematica that facilitates the numerical computation of the quasinormal mode (QNM) spectrum of a black hole/black brane. Requiring as input only the QNM equation(s), the application of a single Mathematica function will compute ... More
Resolution studies with the DATURA beam telescopeOct 08 2016Nov 07 2016Detailed studies of the resolution of a EUDET-type beam telescope are carried out using the DATURA beam telescope as an example. The EUDET-type beam telescopes make use of CMOS MIMOSA 26 pixel detectors for particle tracking allowing for precise characterisation ... More
Radiation damage of the ILC positron source targetDec 14 2007The radiation damage of the positron source target for the International Linear Collider (ILC) has been studied. The displacement damage in target material due to multi-MeV photons has been calculated by combining FLUKA simulations for secondary particle ... More
Subalgebras of Cohen algebras need not be CohenOct 15 1996We give an example of a regular and complete subalgebra of a Cohen algebra which is not Cohen.
ROSAT/HRI study of the optically rich, lensing cluster CL0500-24Jul 12 1996An analysis of a ROSAT/HRI observation of the optically rich, gravitationally lensing galaxy cluster CL0500-24 (or Abell S0506) is presented. We show that the X-ray luminosity of this supposedly rich cluster is relatively low at $1.1^{+0.2}_{-0.1}\times10^{44}$ ... More
Photovoltage from ferroelectric domain walls in BiFeO$_3$May 24 2019It has been debated for a decade whether the photovoltage in BiFeO$_3$ originates in a bulk photovoltaic effect, a ferroelectric domain-wall effect, or a combination of both. In order to elucidate the role of ferroelectric domain walls for the photovoltaic ... More
Organization and Independence or Interdependence? Study of the Neurophysiological Dynamics of Syntactic and Semantic ProcessingApr 16 2018In this article we present a multivariate model for determining the different syntactic, semantic, and form (surface-structure) processes underlying the comprehension of simple phrases. This model is applied to EEG signals recorded during a reading task. ... More
A first XMM-Newton look at the most X-ray-luminous galaxy cluster RX J1347.5-1145Dec 09 2004We present the first results from an XMM-Newton observation of RX J1347.5-1145 (z=0.451), the most luminous X-ray cluster of galaxies currently known, with a luminosity L_X = 6.0 \pm 0.1 \times 10^{45} erg/s in the [2-10] keV energy band. The cluster ... More
Sensitivity of the Geomagnetic Octupole to a Stably Stratified Layer in the Earth's CoreOct 09 2018Current "Earth-like" numerical dynamo simulations are able to reproduce many characteristics of the observed geomagnetic field. One notable exception is the geomagnetic octupolar component. Here we investigate whether a stably stratified layer at the ... More
Projective cases for the restriction of the oscillator representation to dual pairsNov 28 2017Jan 23 2019We study here the restriction of the oscillator representation of the symplectic group $Sp(2p(m+n),\mathbb{R})$ to two different subgroups, namely $O(m,n)$ and $Sp(2p,\mathbb{R})$. We use the duality correspondence introduced by Howe to analyze these ... More
Cross-Ownership as a Structural Explanation for Over- and Underestimation of Default ProbabilityJan 25 2013Based on the work of Suzuki (2002), we consider a generalization of Merton's asset valuation approach (Merton, 1974) in which two firms are linked by cross-ownership of equity and liabilities. Suzuki's results then provide no arbitrage prices of firm ... More
Speeding up the HMC: QCD with Clover-Improved Wilson FermionsOct 18 2002Oct 26 2002We apply a recent proposal to speed up the Hybrid-Monte-Carlo simulation of systems with dynamical fermions to two flavor QCD with clover-improvement. For our smallest quark masses we see a speed-up of more than a factor of two compared with the standard ... More
Speeding up the Hybrid-Monte-Carlo algorithm for dynamical fermionsOct 22 2001We propose a modification of the Hybrid-Monte-Carlo algorithm that allows for a larger step-size of the integration scheme at constant acceptance rate. The key ingredient is the splitting of the pseudo-fermion action into two parts. We test our proposal ... More
Anomalous scaling in the random-force-driven Burgers equation: A Monte Carlo studyNov 03 2011We present a new approach to determine the small-scale statistical behavior of hydrodynamic turbulence by means of lattice simulations. Using the functional integral representation of the random-force-driven Burgers equation we show that high-order moments ... More
The PHMC algorithm for simulations of dynamical fermions: I -- description and propertiesAug 12 1998We give a detailed description of the so-called Polynomial Hybrid Monte Carlo (PHMC) algorithm. The effects of the correction factor, which is introduced to render the algorithm exact, are discussed, stressing their relevance for the statistical fluctuations ... More
Implementation of Symanzik's Improvement Program for Simulations of Dynamical Wilson Fermions in Lattice QCDMar 14 1996Mar 22 1996We discuss the implementation of a Sheikholeslami-Wohlert term for simulations of lattice QCD with dynamical Wilson fermions as required by Symanzik's improvement program. We show that for the Hybrid Monte Carlo or Kramers equation algorithm standard ... More
Improved approximation for two dimensional strip packing with polynomial bounded widthOct 14 2016We study the well-known two-dimensional strip packing problem. Given is a set of rectangular axis-parallel items and a strip of width $W$ with infinite height. The objective is to find a packing of these items into the strip, which minimizes the packing ... More
From Bijels to Pickering emulsions: a lattice Boltzmann studyApr 26 2010Feb 12 2011Particle stabilized emulsions are ubiquitous in the food and cosmetics industry, but our understanding of the influence of microscopic fluid-particle and particle-particle interactions on the macroscopic rheology is still limited. In this paper we present ... More
Quantum computing of zeta-regularized vacuum expectation valuesAug 21 2018Sep 23 2018It has recently been shown that vacuum expectation values and Feynman path integrals can be regularized using Fourier Integral Operator $\zeta$-function, yet the physical meaning of these $\zeta$-regularized objects was unknown. Here we show that $\zeta$-regularized ... More
Tunneling and Energy Splitting in Ising ModelsMay 18 1992The energy splitting $E_{0a}$ in two and four dimensional Ising models is measured in a cylindrical geometry on finite lattices. By comparing to exact results in the two dimensional Ising model we demonstrate that $E_{0a}$ can be extracted very reliably ... More
An Introduction To Monte Carlo Simulations Of Surface ReactionsMar 03 2003These are lecture notes of a course that I gave to people doing research for their Ph.D. thesis in theoretical chemistry or spectroscopy. The course was given on December 9-13, 2002, in Han-sur-Lesse, Belgium. The lecture notes start with the lattice-gas ... More
Scheduling Monotone Moldable Jobs in Linear TimeOct 31 2017Jan 07 2018A moldable job is a job that can be executed on an arbitrary number of processors, and whose processing time depends on the number of processors allotted to it. A moldable job is monotone if its work doesn't decrease for an increasing number of allotted ... More
A note on the integrality gap of the configuration LP for restricted Santa ClausJul 10 2018In the restricted Santa Claus problem we are given resources $\mathcal R$ and players $\mathcal P$. Every resource $j\in\mathcal R$ has a value $v_j$ and every player $i$ desires a set $\mathcal R(i)$ of resources. We are interested in distributing the ... More
On the Configuration-LP of the Restricted Assignment ProblemNov 07 2016Jan 13 2017We consider the classical problem of Scheduling on Unrelated Machines. In this problem a set of jobs is to be distributed among a set of machines and the maximum load (makespan) is to be minimized. The processing time $p_{ij}$ of a job $j$ depends on ... More
Turing Kernelization for Finding Long Paths and Cycles in Restricted Graph ClassesFeb 19 2014Jan 29 2016The NP-complete $k$-Path problem asks whether a given undirected graph has a (simple) path of length at least $k$. We prove that $k$-Path has polynomial-size Turing kernels when restricted to planar graphs, graphs of bounded degree, claw-free graphs, ... More
Improvements on the distribution of maximal segmental scores in a Markovian sequenceMar 07 2018Let $(A_i)_{i \geq 0}$ be a finite state irreducible aperiodic Markov chain and $f$ a lattice score function such that the average score is negative and positive scores are possible. Define $S_0:=0$ and $S_k:=\sum_{i=1}^k f(A_i)$ the successive partial ... More
Anomalous scaling in the random-force-driven Burgers equation: A Monte Carlo studyApr 07 2011Oct 07 2011We present a new approach to determine numerically the statistical behavior of small-scale structures in hydrodynamic turbulence. Starting from the functional integral representation of the random-force-driven Burgers equation we show that Monte Carlo ... More
Speeding up Lattice QCD simulations with clover-improved Wilson FermionsNov 29 2002We apply a recent proposal to speed up the Hybrid-Monte-Carlo simulation of systems with dynamical fermions to two flavour QCD with clover-improvement. The basic idea of our proposal is to split the fermion matrix into two factors with a reduced condition ... More
The non-perturbative O(a)-improved action for dynamical Wilson fermionsSep 10 1997We compute the improvement coefficient $c_{sw}$ that multiplies the Sheikholeslami-Wohlert term as a function of the bare gauge coupling for two flavour QCD. We discuss several aspects concerning simulations with improved dynamical Wilson fermions.
(Non)renormalization of Anomalous Conductivities and HolographyJul 11 2014Aug 06 2014The chiral magnetic and the chiral vortical effects are recently discovered phenomena arising from chiral gauge and gravitational anomalies that lead to generation of electric currents in presence of magnetic field or vorticity. The magnitude of these ... More
A Quasi-Polynomial Approximation for the Restricted Assignment ProblemJan 25 2017Scheduling jobs on unrelated machines and minimizing the makespan is a classical problem in combinatorial optimization. In this problem a job $j$ has a processing time $p_{ij}$ for every machine $i$. The best polynomial algorithm known goes back to Lenstra ... More
Local search breaks 1.75 for Graph BalancingNov 02 2018Graph Balancing is the problem of orienting the edges of a weighted multigraph so as to minimize the maximum weighted in-degree. Since the introduction of the problem the best algorithm known achieves an approximation ratio of $1.75$ and it is based on ... More
Closing the gap for pseudo-polynomial strip packingDec 13 2017Feb 06 2019The set of 2-dimensional packing problems builds an important class of optimization problems and Strip Packing together with 2-dimensional Bin Packing and 2-dimensional Knapsack is one of the most famous of these problems. Given a set of rectangular axis ... More
Kramers equation algorithm for simulations of QCD with two flavors of Wilson fermions and gauge group SU(2)Jun 13 1995We compare the Hybrid Monte Carlo (HMC) and the Kramers equation algorithms for simulations of QCD with two flavors of dynamical Wilson fermions and gauge group $SU(2)$. The results for the performance of both algorithms are obtained on $6^312$, $12^4$ ... More
tmLQCD: a program suite to simulate Wilson Twisted mass Lattice QCDMay 20 2009We discuss a program suite for simulating Quantum Chromodynamics on a 4-dimensional space-time lattice. The basic Hybrid Monte Carlo algorithm is introduced and a number of algorithmic improvements are explained. We then discuss the implementations of ... More
Upper and lower Higgs boson mass bounds from a lattice Higgs-Yukawa model with dynamical overlap fermionsDec 02 2009We study a lattice Higgs-Yukawa model emulating the same Higgs-fermion coupling structure as in the Higgs sector of the electroweak Standard Model, in particular, obeying a Ginsparg-Wilson version of the underlying SU(2) x U(1) symmetry, being a global ... More
On the phase structure of a chiral invariant Higgs-Yukawa modelOct 02 2006Jan 09 2007In the past the construction of Higgs-Yukawa models on the lattice was blocked by the lack of a consistent definition of a chiral invariant Yukawa coupling term. Here, we consider a chiral invariant Higgs-Yukawa model based on the overlap operator, realized ... More
An EPTAS for Scheduling on Unrelated Machines of Few Different TypesJan 12 2017Dec 06 2017In the classical problem of scheduling on unrelated parallel machines, a set of jobs has to be assigned to a set of machines. The jobs have a processing time depending on the machine and the goal is to minimize the makespan, that is the maximum machine ... More
A Monte Carlo study of temperature-programmed desorption spectra with attractive lateral interactionsFeb 20 1995May 11 1995We present results of a Monte Carlo study of temperature-programmed desorption in a model system with attractive lateral interactions. It is shown that even for weak interactions there are large shifts of the peak maximum temperatures with initial coverage. ... More
Experiences with the Polynomial Hybrid Monte Carlo AlgorithmSep 12 1997We discuss a simulation algorithm for dynamical fermions, which combines the multiboson technique with the Hybrid Monte Carlo algorithm. The algorithm turns out to give a substantial gain over standard methods in practical simulations and to be suitable ... More
Study of Liapunov Exponents and the Reversibility of Molecular Dynamics AlgorithmsJul 25 1996We study the question of lack of reversibility and the chaotic nature of the equations of motion in numerical simulations of lattice QCD.
A Polynomial Hybrid Monte Carlo AlgorithmFeb 14 1997We present a simulation algorithm for dynamical fermions that combines the multiboson technique with the Hybrid Monte Carlo algorithm. We find that the algorithm gives a substantial gain over the standard methods in practical simulations. We point out ... More
Critical Momenta of Lattice Chiral FermionsSep 01 1992We determine the critical momenta for chiral fermions in the domain wall model recently suggested by Kaplan. For a wide range of domain wall masses $m$ and Wilson couplings $r$ we explicitly exhibit the regions in momentum space where the fermions are ... More
The epsilon regime of chiral perturbation theory with Wilson-type fermionsNov 10 2009In this proceeding contribution we report on the ongoing effort to simulate Wilson-type fermions in the so called epsilon regime of chiral perturbation theory. We present results for the chiral condensate and the pseudoscalar decay constant obtained with ... More
On the Configuration-LP of the Restricted Assignment ProblemNov 07 2016We consider the classical problem of Scheduling on Unrelated Machines. In this problem a set of jobs is to be distributed among a set of machines and the maximum load (makespan) is to be minimized. The processing time $p_{ij}$ of a job $j$ depends on ... More
The phase structure of a chirally invariant lattice Higgs-Yukawa model - numerical simulationsJul 26 2007The phase diagram of a chirally invariant lattice Higgs-Yukawa model is explored by means of numerical simulations. The results revealing a rich phase structure are compared to analytical large Nf calculations which we performed earlier. The analytical ... More
Feasibility of track-based multiple scattering tomographySep 04 2017Sep 05 2017We present a tomographic technique making use of a gigaelectronvolt electron beam for the measurement of the spatial material budget distribution of centimetre-sized objects. With simulation tools originating from high-energy physics applications, a test ... More
Development and simulations of Enhanced Lateral Drift SensorsMay 08 2019We present the concept of a new type of silicon tracking sensor called Enhanced Lateral Drift (ELAD) sensor. In ELAD sensors the spatial resolution of the impact position of ionising particles is improved by a dedicated charge sharing mechanism, which ... More
Extracting Core Claims from Scientific ArticlesJul 24 2017The number of scientific articles has grown rapidly over the years and there are no signs that this growth will slow down in the near future. Because of this, it becomes increasingly difficult to keep up with the latest developments in a scientific field. ... More
On Structural Parameterizations of Hitting Set: Hitting Paths in Graphs Using 2-SATJul 21 2015Jul 24 2015Hitting Set is a classic problem in combinatorial optimization. Its input consists of a set system F over a finite universe U and an integer t; the question is whether there is a set of t elements that intersects every set in F. The Hitting Set problem ... More
Upper Higgs boson mass bounds from a chirally invariant lattice Higgs-Yukawa modelFeb 23 2010We establish the cutoff-dependent upper Higgs boson mass bound by means of direct lattice computations in the framework of a chirally invariant lattice Higgs-Yukawa model emulating the same chiral Yukawa coupling structure as in the Higgs-fermion sector ... More
O(a) improvement of lattice QCD with two flavors of Wilson quarksMar 23 1998Jul 11 2002We consider O(a) improvement for two flavor lattice QCD. The improvement term in the action is computed non-perturbatively for a large range of the bare coupling. The position of the critical line and higher order lattice artifacts remaining after improvement ... More
Island formation without attractive interactionsFeb 18 2008We show that adsorbates on surfaces can form islands even if there are no attractive interactions. Instead strong repulsion between adsorbates at short distances can lead to islands, because such islands increase the entropy of the adsorbates that are ... More
Stochastic gene expression with delayMay 28 2013Aug 07 2014The expression of genes usually follows a two-step procedure. First, a gene (encoded in the genome) is transcribed resulting in a strand of (messenger) RNA. Afterwards, the RNA is translated into protein. Classically, this gene expression is modeled using ... More
On Integer Programming and ConvolutionMar 13 2018Nov 05 2018Integer programs with a constant number of constraints are solvable in pseudo-polynomial time. We give a new algorithm with a better pseudo-polynomial running time than previous results. Moreover, we establish a strong connection to the problem (min, ... More
Linear Time Algorithms for Multiple Cluster Scheduling and Multiple Strip PackingFeb 09 2019We study the Multiple Cluster Scheduling problem and the Multiple Strip Packing problem. For both problems, there is no algorithm with approximation ratio better than $2$ unless $P = NP$. In this paper, we present an algorithm with approximation ratio ... More
Kepler's Dark Worlds: a Low Albedo for an Ensemble of Neptunian and Terran ExoplanetsOct 27 2017Photometric phase curves provide an important window onto exoplanetary atmospheres and potentially even their surfaces. With similar amplitudes to occultations but far longer baselines, they have a higher sensitivity to planetary photons at the expense ... More