Results for "Lukas Simon"

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Stochastic Proximal Gradient Algorithms for Multi-Source Quantitative Photoacoustic TomographyJan 22 2018Mar 28 2018The development of accurate and efficient image reconstruction algorithms is a central aspect of quantitative photoacoustic tomography (QPAT). In this paper, we address this issues for multi-source QPAT using the radiative transfer equation (RTE) as accurate ... More
Towards Blockchain-based Auditable Storage and Sharing of IoT DataMay 22 2017Nov 14 2017Today the cloud plays a central role in storing, processing, and distributing data. Despite contributing to the rapid development of IoT applications, the current IoT cloud-centric architecture has led into a myriad of isolated data silos that hinders ... More
Analysis of the Linearized Problem of Quantitative Photoacoustic TomographyFeb 15 2017Quantitative image reconstruction in photoacoustic tomography requires the solution of a coupled physics inverse problem involvier light transport and acoustic wave propagation. In this paper we address this issue employing the radiative transfer equation ... More
vh@nnlo-v2: New physics in Higgs StrahlungFeb 13 2018Introducing version 2 of the code vh@nnlo, we study the effects of a number of new-physics scenarios on the Higgs-Strahlung process. In particular, the cross section is evaluated within a general 2HDM and the MSSM. While the Drell-Yan-like contributions ... More
Design Considerations of Biaxially Tensile-Strained Germanium-on-Silicon LasersNov 18 2015Dec 14 2015Physical models of Ge energy band structure and material loss were implemented in LASTIP(TM), a 2D simulation tool for edge emitting laser diodes. The model calculation is able to match experimental data available. Important design parameters of a Fabry-Perot ... More
Highly selective dry etching of GaP in the presence of Al$_\textrm{x}$Ga$_{1-\textrm{x}}$PJan 19 2018We present an inductively coupled-plasma reactive-ion etching process that simultaneously provides both a high etch rate and unprecedented selectivity for gallium phosphide (GaP) in the presence of aluminum gallium phosphide (Al$_\textrm{x}$Ga$_{1-\textrm{x}}$P). ... More
GPdoemd: a Python package for design of experiments for model discriminationOct 05 2018Jan 14 2019Model discrimination identifies a mathematical model that usefully explains and predicts a given system's behaviour. Researchers will often have several models, i.e.\ hypotheses, about an underlying system mechanism, but insufficient experimental data ... More
Self-organizing magnetic beads for biomedical applicationsOct 05 2011In the field of biomedicine magnetic beads are used for drug delivery and to treat hyperthermia. Here we propose to use self-organized bead structures to isolate circulating tumor cells using lab-on-chip technologies. Typically blood flows past microposts ... More
The Little Bundles OperadJan 15 2019Feb 10 2019Hurwitz spaces are homotopy quotients of the braid group action on the moduli space of principal bundles over a punctured plane. By considering a certain model for this homotopy quotient we build an aspherical topological operad that we call the little ... More
The structure of DGA resolutions of monomial idealsOct 20 2016Let $I \subset k[x_1, \dotsc, x_n]$ be a squarefree monomial ideal a polynomial ring. In this paper we study multiplications on the minimal free resolution $\mathbb{F}$ of $S/I$. In particular, we characterize the possible vectors of total Betti numbers ... More
The structure of DGA resolutions of monomial idealsOct 20 2016Jun 20 2018Let $I \subset k[x_1, \dotsc, x_n]$ be a squarefree monomial ideal a polynomial ring. In this paper we study multiplications on the minimal free resolution $\mathbb{F}$ of $k[x_1, \dotsc, x_n]/I$. In particular, we characterize the possible vectors of ... More
Algebraic Multilevel Methods for Markov ChainsNov 12 2017Dec 30 2017A new algebraic multilevel algorithm for computing the second eigenvector of a column-stochastic matrix is presented. The method is based on a deflation approach in a multilevel aggregation framework. In particular a square and stretch approach, first ... More
Polytopal affine semigroups with holes deep insideOct 16 2012Mar 20 2013Given a non-negative integer k, we construct a lattice 3-simplex P with the following property: The affine semigroup Q_P associated to P is not normal, and every element $q \in \sat{Q}_P \setminus Q_P$ has lattice distance at least k above every facet ... More
Sharp bounds for the valence of certain harmonic polynomialsOct 25 2005D. Khavinson and G. Swiatek proved that harmonic polynomials p(z)+q(z), where p is holomorphic, q is antiholomorphic, and deg p = n > 1 = deg q, can have at most 3n-2 complex zeros. We show that this bound is sharp for all n by proving a conjecture of ... More
The Linear Ordering Polytope via RepresentationsSep 23 2011Oct 25 2011Let $P_n$ denote the $n$-th linear ordering polytope. We define projections from $P_n$ to the $n$-th permutahedron and to the $(n-1)$-st linear ordering polytope. Both projections are equivariant with respect to the natural $\Sn$-action and they project ... More
A non-Golod ring with a trivial product on its Koszul homologyNov 16 2015Jan 30 2017We present a monomial ideal $\mathfrak{a} \subset S$ such that $S/\mathfrak{a}$ is not Golod, even though the product on its Koszul homology is trivial. This constitutes a counterexample to a well-known result by Berglund and J\"ollenbeck (the error can ... More
Linearity in minimal resolutions of monomial idealsFeb 24 2017Mar 24 2017Let $S = k[x_1, \dotsc, x_n]$ be a polynomial ring over a field $k$ and let $M$ be a graded $S$-module with minimal free resolution $\mathbb{F}_\bullet$. Its linear part $lin(\mathbb{F}_\bullet)$ is obtained by deleting all non-linear entries from the ... More
SL(n)-Covariant $L_p$-Minkowski ValuationsSep 18 2012Jul 01 2015All continuous SL(n)-covariant $L_p$-Minkowski valuations defined on convex bodies are completely classified. The $L_p$-moment body operators turn out to be the nontrivial prototypes of such maps.
Stanley depth and simplicial spanning treesOct 14 2014Mar 09 2015We show that for proving the Stanley conjecture, it is sufficient to consider a very special class of monomial ideals. These ideals (or rather their lcm lattices) are in bijection with the simplicial spanning trees of skeletons of a simplex. We apply ... More
Completing the classification of representations of $\mathrm{SL}_n$ with complete intersection invariant ringDec 05 2018We present a full list of all representations of the special linear group $\mathrm{SL}_n$ over the complex numbers with complete intersection invariant ring, completing the classification of Shmelkin. For this task, we combine three techniques. Firstly, ... More
On the Complexity of SailsFeb 07 2011Dec 15 2011This paper analyses stable commutator length in groups Z^r * Z^s. We bound scl from above in terms of the reduced wordlength (sharply in the limit) and from below in terms of the answer to an associated subset-sum type problem. Combining both estimates, ... More
On eigenvalue and eigenvector estimates for nonnegative definite operatorsMar 16 2005In this article we further develop a perturbation approach to the Rayleigh--Ritz approximations from our earlier work. We both sharpen the estimates and extend the applicability of the theory to nonnegative definite operators . The perturbation argument ... More
Invariant rings of sums of fundamental representations of ${\rm SL}_n$ and colored hypergraphsJul 25 2018The fundamental representations of the special linear group ${\rm SL}_n$ over the complex numbers are the exterior powers of $\mathbb{C}^n$. We consider the invariant rings of sums of arbitrary many copies of these ${\rm SL}_n$-modules. The symbolic method ... More
Decomposing Sets of InversionsNov 15 2011Aug 06 2012In this note we consider the question how the set of inversions of a permutation $\pi \in S_n$ can be partitioned into two subset, such that those are itself inversion sets of permutations. This is archived by exploiting a connection to a graph theoretical ... More
SL(n)-Contravariant $L_p$-Minkowski ValuationsOct 26 2014All SL(n)-contravariant $L_p$-Minkowski valuations on polytopes are completely classified. The prototypes of such valuations turn out to be the asymmetric $L_p$-projection body operators.
Non-normal affine monoidsSep 27 2012Jun 07 2015We give a geometric description of the set of holes in a non-normal affine monoid $Q$. The set of holes turns out to be related to the non-trivial graded components of the local cohomology of $k[Q]$. From this, we see how various properties of $k[Q]$ ... More
On the exceptional set in a conditional theorem of LittlewoodApr 03 2014Sep 11 2014In 1952, Littlewood stated a conjecture about the average growth of spherical derivatives of polynomials, and showed that it would imply that for entire function of finite order, "most" preimages of almost all points are concentrated in a small subset ... More
Single-stage reconstruction algorithm for quantitative photoacoustic tomographyJan 19 2015Mar 25 2015The development of efficient and accurate image reconstruction algorithms is one of the cornerstones of computed tomography. Existing algorithms for quantitative photoacoustic tomography currently operate in a two-stage procedure: First an inverse source ... More
Analysis of the Block Coordinate Descent Method for Non-linear Ill-Posed ProblemsFeb 13 2019Block coordinate descent (BCD) methods approach optimization problems by performing gradient steps along alternating subgroups of coordinates. This is in contrast to full gradient descent, where a gradient step updates all coordinates simultaneously. ... More
Stochastic Proximal Gradient Algorithms for Multi-Source Quantitative Photoacoustic TomographyJan 22 2018Feb 08 2018The development of accurate and efficient image reconstruction algorithms is a central aspect of quantitative photoacoustic tomography (QPAT). In this paper, we address this issues for multi-source QPAT using the radiative transfer equation (RTE) as accurate ... More
On conditional moments of high-dimensional random vectors given lower-dimensional projectionsMay 09 2014Sep 06 2016One of the most widely used properties of the multivariate Gaussian distribution, besides its tail behavior, is the fact that conditional means are linear and that conditional variances are constant. We here show that this property is also shared, in ... More
Quantitative height bounds under splitting conditionsAug 06 2015Sep 12 2018In an earlier work, the first author and Petsche used potential theoretic techniques to establish a lower bound for the height of algebraic numbers that satisfy splitting conditions, such as being totally real or p-adic, improving on earlier work of Bombieri ... More
Quasi-Polynomial Local Search for Restricted Max-Min Fair AllocationMay 07 2012Jan 17 2014The restricted max-min fair allocation problem (also known as the restricted Santa Claus problem) is one of few problems that enjoys the intriguing status of having a better estimation algorithm than approximation algorithm. Indeed, Asadpour et al. proved ... More
Statistical inference with F-statistics when fitting simple models to high-dimensional dataFeb 12 2019We study linear subset regression in the context of the high-dimensional overall model $y = \vartheta+\theta' z + \epsilon$ with univariate response $y$ and a $d$-vector of random regressors $z$, independent of $\epsilon$. Here, "high-dimensional" means ... More
The $v_n$-periodic Goodwillie tower on Wedges and CofibresDec 08 2016We introduce general methods to analyse the Goodwillie tower of the identity functor on a wedge $X \vee Y$ of spaces (using the Hilton-Milnor theorem) and on the cofibre $\mathrm{cof}(f)$ of a map $f: X \rightarrow Y$. We deduce some consequences for ... More
Edge rings satisfying Serre's condition R_1Feb 22 2012Aug 06 2012A combinatorial criterion for the edge ring of a finite connected graph to satisfy Serre's condition R_1 is studied.
Convergence analysis of Strang splitting for Vlasov-type equationsJul 09 2012May 01 2013A rigorous convergence analysis of the Strang splitting algorithm for Vlasov-type equations in the setting of abstract evolution equations is provided. It is shown that under suitable assumptions the convergence is of second order in the time step \tau. ... More
On the inverse Klain mapJun 23 2012Nov 15 2012The continuity of the inverse Klain map is investigated and the class of centrally symmetric convex bodies at which every valuation depends continuously on its Klain function is characterized. Among several applications, it is shown that McMullen's decomposition ... More
Canonical threefold singularities with a torus action of complexity one and $k$-empty polytopesJul 20 2018We classify the canonical threefold singularities that allow an effective two-torus action. This extends classification results of Mori on terminal threefold singularities and of Ishida and Iwashita on toric canonical threefold singularities. Our classification ... More
An introduction to matrix convex sets and free spectrahedraNov 09 2016Sep 06 2018The purpose of this paper is to give a self-contained overview of the theory of matrix convex sets and free spectrahedra. We will give new proofs and generalizations of key theorems. However we will also introduce various new concepts and results as well. ... More
The Action of Young Subgroups on the Partition ComplexJan 04 2018Mar 06 2018We study the restrictions, the strict fixed points, and the strict quotients of the partition complex $|\Pi_n|$, which is the $\Sigma_n$-space attached to the poset of proper nontrivial partitions of the set $\{1,\ldots,n\}$. We express the space of fixed ... More
The Tu--Deng Conjecture holds almost surelyJul 25 2017Jul 10 2018The Tu--Deng Conjecture is concerned with the sum of digits $w(n)$ of $n$ in base~$2$ (the Hamming weight of the binary expansion of $n$) and states the following: assume that $k$ is a positive integer and $1\leq t<2^k-1$. Then \[\Bigl \lvert\Bigl\{(a,b)\in\bigl\{0,\ldots,2^k-2\bigr\}^2:a+b\equiv ... More
Valuations and Surface Area MeasuresOct 26 2014We consider valuations defined on polytopes containing the origin which have measures on the sphere as values. We show that the classical surface area measure is essentially the only such valuation which is SL(n) contravariant of degree one. Moreover, ... More
A Canonical module characterization of Serre's $(\mathrm{R}_1)$Jun 08 2015Jan 19 2016In this short note, we give a characterization of domains satisfying Serre's condition $(\mathrm{R}_1)$ in terms of their canonical modules. In the special case of toric rings, this generalizes a result of the second author (K. Yanagawa, Dualizing complexes ... More
An almost symmetric Strang splitting scheme for the construction of high order composition methodsJun 05 2013Dec 19 2013In this paper we consider splitting methods for nonlinear ordinary differential equations in which one of the (partial) flows that results from the splitting procedure can not be computed exactly. Instead, we insert a well-chosen state $y_{\star}$ into ... More
Church-Rosser Systems, Codes with Bounded Synchronization Delay and Local Rees ExtensionsJul 01 2017What is the common link, if there is any, between Church-Rosser systems, prefix codes with bounded synchronization delay, and local Rees extensions? The first obvious answer is that each of these notions relates to topics of interest for WORDS: Church-Rosser ... More
The Stanley Depth in the Upper Half of the Koszul ComplexAug 25 2014Nov 17 2014Let $R = K[X_1, ..., X_n]$ be a polynomial ring over some field $K$. In this paper, we prove that the $k$-th syzygy module of the residue class field $K$ of $R$ has Stanley depth $n-1$ for $\lfloor n/2 \rfloor \leq k < n$, as it had been conjectured by ... More
The Centro-Affine Hadwiger TheoremJul 02 2013All upper semicontinuous and SL(n) invariant valuations on convex bodies containing the origin in their interiors are completely classified. Each such valuation is shown to be a linear combination of the Euler characteristic, the volume, the volume of ... More
Asymmetric domain walls of small angle in soft ferromagnetic filmsDec 07 2014We focus on a special type of domain walls appearing in the Landau-Lifshitz theory for soft ferromagnetic films. These domain walls are divergence-free $S^2$-valued transition layers that connect two directions in $S^2$ (differing by an angle $2\theta$) ... More
Upsilon-like concordance invariants from sl(n) knot cohomologyJul 04 2017We construct smooth concordance invariants of knots which take the form of piecewise linear maps from [0,1] to R, one for each n greater than or equal to 2. These invariants arise from sl(n) knot cohomology. We verify some properties which are analogous ... More
Overcoming order reduction in diffusion-reaction splitting. Part 1: Dirichlet boundary conditionsNov 03 2014For diffusion-reaction equations employing a splitting procedure is attractive as it reduces the computational demand and facilitates a parallel implementation. Moreover, it opens up the possibility to construct second-order integrators that preserve ... More
The Intersection Problem for Finite MonoidsNov 23 2017Feb 02 2018We investigate the intersection problem for finite monoids, which asks for a given set of regular languages, represented by recognizing morphisms to finite monoids from a variety V, whether there exists a word contained in their intersection. Our main ... More
On consistency of the likelihood moment estimators for a linear process with regularly varying innovationsJul 13 2015May 25 2016In 1975 James Pickands III showed that the excesses over a high threshold are approximatly Generalized Pareto distributed. Since then, a variety of estimators for the parameters of this cdf have been studied, but always assuming the underlying data to ... More
Soft See-Saw: Radiative Origin of Neutrino Masses in SUSY TheoriesSep 23 2016Radiative neutrino mass generation within supersymmetric (SUSY) construction is studied. The mechanism is considered where the lepton number violation is originating from the soft SUSY breaking terms. This requires extensions of the MSSM with states around ... More
Kahler Potential for M-theory on a G_2 ManifoldMay 09 2003Nov 21 2003We compute the moduli Kahler potential for M-theory on a compact manifold of G_2 holonomy in a large radius approximation. Our method relies on an explicit G_2 structure with small torsion, its periods and the calculation of the approximate volume of ... More
A simple explicitly solvable interacting relativistic N-particle modelFeb 03 2015In this paper, we generalize a previous relativistic $1+1$-dimensional model for two mass-less Dirac particles with relativistic contact interactions to the $N$-particle case. Our model is based on the notion of a multi-time wave function which, according ... More
A quasi-conservative dynamical low-rank algorithm for the Vlasov equationJul 06 2018Numerical methods that approximate the solution of the Vlasov-Poisson equation by a low-rank representation have been considered recently. These methods can be extremely effective from a computational point of view, but contrary to most Eulerian Vlasov ... More
On weakly formulated Sylvester equations and applicationsJul 26 2005We use a ``weakly formulated'' Sylvester equation $$A^{1/2}TM^{-1/2}-A^{-1/2}TM^{1/2}=F$$ to obtain new bounds for the rotation of spectral subspaces of a nonnegative selfadjoint operator in a Hilbert space. Our bound extends the known results of Davis ... More
Centro-Affine Tensor ValuationsSep 13 2015We completely classify all measurable $\operatorname{SL}(n)$-covariant symmetric tensor valuations on convex polytopes containing the origin in their interiors. It is shown that essentially the only examples of such valuations are the moment tensor and ... More
On stable sl3-homology of torus knotsApr 02 2014The stable Khovanov-Rozansky homology of torus knots has been conjecturally described as the Koszul homology of an explicit non-regular sequence of polynomials. We verify this conjecture against newly available computational data for sl(3)-homology. Special ... More
On classical upper bounds for slice generaNov 08 2016Aug 16 2018We introduce a new link invariant called the algebraic genus, which gives an upper bound for the topological slice genus of links. In fact, the algebraic genus is an upper bound for another version of the slice genus proposed here: the minimal genus of ... More
Reconstruction theorem for complex polynomialsFeb 01 2015May 01 2015Recently Takens' Reconstruction Theorem was studied in the complex analytic setting by Forn{\ae}ss and Peters \cite{FP}. They studied the real orbits of complex polynomials, and proved that for non-exceptional polynomials ergodic properties such as measure ... More
Multi-time formulation of particle creation and annihilation via interior-boundary conditionsAug 13 2018Sep 21 2018Interior-boundary conditions (IBCs) have been suggested as a possibility to circumvent the problem of ultraviolet divergences in quantum field theories. In the IBC approach, particle creation and annihilation is described with the help of linear conditions ... More
Asymptotic normality of the likelihood moment estimators for a stationary linear process with heavy-tailed innovationsMay 25 2016A variety of estimators for the parameters of the Generalized Pareto distribution, the approximating distribution for excesses over a high threshold, have been proposed, always assuming the underlying data to be independent. We recently proved that the ... More
Estimating the density of a set of primes with applications to group theoryOct 19 2018Dec 26 2018We estimate the asymptotic density of the set $\bar{A}$ of primes $p$ satisfying the constraint that $p+1$ and $p-1$ have only one prime divisor larger than $3$. We also estimate the density of a maximal subset $\bar{B} \subset \bar{A}$ such that for ... More
The maximal order of hyper-($b$-ary)-expansionsNov 26 2015Using methods developed by Coons and Tyler, we give a new proof of a recent result of Defant, by determining the maximal order of the number of hyper-($b$-ary)-expansions of a nonnegative integer $n$ for general integral bases $b\geqslant 2$.
Influence of the Hall-bar geometry on harmonic Hall voltage measurements of spin-orbit torquesApr 20 2018Harmonic Hall voltage measurements are a wide-spread quantitative technique for the measurement of spin-orbit induced effective fields in heavy-metal / ferromagnet heterostructures. In the vicinity of the voltage pickup lines in the Hall bar, the current ... More
Green's Relations in Finite Transformation SemigroupsMar 15 2017We consider the complexity of Green's relations when the semigroup is given by transformations on a finite set. Green's relations can be defined by reachability in the (right/left/two-sided) Cayley graph. The equivalence classes then correspond to the ... More
Fine asymptotics for models with Gamma type momentsOct 17 2017The aim of this paper is to give fine asymptotics for random variables with moments of Gamma type. Among the examples we consider are random determinants of Laguerre and Jacobi beta ensembles with varying dimensions (the number of observed variables and ... More
Gap control in phosphorene/BN structures from first principles calculationsJul 27 2016Using both DFT as well as $G_0W_0$ calculations, we investigate static and dynamic effects on the phosphorene band gap upon deposition and encapsulation on/in BN multilayers. We demonstrate how competing long- and short-range effects cause the phosphorene ... More
Cichoń's Diagram and Localisation CardinalsAug 06 2018Aug 28 2018We reimplement the creature forcing construction used by Fischer et al. (arXiv:1402.0367) to separate Cicho\'{n}'s diagram into five cardinals as a countable support product. Using the fact that it is of countable support, we augment our construction ... More
On the exactness of Lasserre relaxations and pure states over real closed fieldsOct 20 2017Nov 29 2018Consider a finite system of non-strict polynomial inequalities with solution set $S\subseteq\mathbb R^n$. Its Lasserre relaxation of degree $d$ is a certain natural linear matrix inequality in the original variables and one additional variable for each ... More
List Decoding of Locally Repairable CodesJan 12 2018May 08 2018We show that locally repairable codes (LRCs) can be list decoded efficiently beyond the Johnson radius for a large range of parameters by utilizing the local error correction capabilities. The new decoding radius is derived and the asymptotic behavior ... More
Reduced dynamical systemsFeb 12 2019We consider the dynamics of complex rational maps on the Riemann sphere. We prove that, after reducing their orbits to a fixed number of positive values representing the Fubini-Study distances between finitely many initial elements of the orbit and the ... More
The Discrete Langevin Machine: Bridging the Gap Between Thermodynamic and Neuromorphic SystemsJan 16 2019A formulation of Langevin dynamics for discrete systems is derived as a new class of generic stochastic processes. The dynamics simplify for a two-state system and suggest a novel network architecture which is implemented by the Langevin machine. The ... More
On the exactness of Lasserre relaxations for compact convex basic closed semialgebraic setsApr 24 2017Feb 28 2018Consider a finite system of non-strict real polynomial inequalities and suppose its solution set $S\subseteq\mathbb R^n$ is convex, has nonempty interior and is compact. Suppose that the system satisfies the Archimedean condition, which is slightly stronger ... More
Valley isospin of interface states in a graphene $pn$ junction in the quantum Hall regimeFeb 21 2019In the presence of crossed electric and magnetic fields, a graphene ribbon has chiral states running along sample edges and along boundaries between $p$-doped and $n$-doped regions. We here consider the scattering of edge states into interface states, ... More
Comparison of models and lattice-gas simulations for Liesegang patternsMar 25 2008For more than a century Liesegang patterns -- self-organized, quasi-periodic structures occurring in diffusion-limited chemical reactions with two components -- have been attracting scientists. The pattern formation can be described by four basic empirical ... More
On Estimating Many Means, Selection Bias, and the BootstrapNov 15 2013With recent advances in high throughput technology, researchers often find themselves running a large number of hypothesis tests (thousands+) and esti- mating a large number of effect-sizes. Generally there is particular interest in those effects estimated ... More
Fast stray field computation on tensor gridsSep 27 2011Sep 30 2011A direct integration algorithm is described to compute the magnetostatic field and energy for given magnetization distributions on not necessarily uniform tensor grids. We use an analytically-based tensor approximation approach for function-related tensors, ... More
A tunable cancer cell filter using magnetic beads: cellular and fluid dynamic simulationsOct 05 2011In the field of biomedicine magnetic beads are used for drug delivery and to treat hyperthermia. Here we propose to use self-organized bead structures to isolate circulating tumor cells using lab-on-chip technologies. Typically blood flows past microposts ... More
Topological Phases: An Expedition off LatticeFeb 01 2011Motivated by the goal to give the simplest possible microscopic foundation for a broad class of topological phases, we study quantum mechanical lattice models where the topology of the lattice is one of the dynamical variables. However, a fluctuating ... More
Centroid Velocity Statistics of Molecular CloudsOct 23 2014We compute structure functions and Fourier spectra of 2D centroid velocity (CV) maps in order to study the gas dynamics of typical molecular clouds (MCs) in numerical simulations. We account for a simplified treatment of time-dependent chemistry and the ... More
LaBonte's method revisited: An effective steepest descent method for micromagnetic energy minimizationSep 23 2013We present a steepest descent energy minimization scheme for micromagnetics. The method searches on a curve that lies on the sphere which keeps the magnitude of the magnetization vector constant. The step size is selected according to a modified Barzilai-Borwein ... More
Unary and Binary Classification Approaches and their Implications for Authorship VerificationDec 31 2018Retrieving indexed documents, not by their topical content but their writing style opens the door for a number of applications in information retrieval (IR). One application is to retrieve textual content of a certain author X, where the queried IR system ... More
Symmetry-protected topological invariant and Majorana impurity states in time-reversal-invariant superconductorsAug 12 2013Jun 02 2015We address the question of whether individual nonmagnetic impurities can induce zero-energy states in time-reversal-invariant topological superconductors, and define a class of symmetries which guarantee the existence of such states for a specific value ... More
Ehrhart Theory of Spanning Lattice PolytopesAug 10 2016A lattice polytope is called spanning if its lattice points affinely span the ambient lattice. We show as a corollary to a general result in the Ehrhart theory of lattice polytopes that the $h^*$-vector of a spanning lattice polytope has no gaps, i. e., ... More
Honeycomb-lattice Heisenberg-Kitaev model in a magnetic field: Spin canting, metamagnetism, and vortex crystalsJul 15 2016Nov 04 2016The Heisenberg-Kitaev model is a paradigmatic model to describe the magnetism in honeycomb-lattice Mott insulators with strong spin-orbit coupling, such as A$_2$IrO$_3$ (A = Na, Li) and $\alpha$-RuCl$_3$. Here we study in detail the physics of the Heisenberg-Kitaev ... More
On side lengths of corners in positive density subsets of the Euclidean spaceSep 28 2016We generalize a result by Cook, Magyar, and Pramanik [3] on three-term arithmetic progressions in subsets of $\mathbb{R}^d$ to corners in subsets of $\mathbb{R}^d\times\mathbb{R}^d$. More precisely, if $1<p<\infty$, $p\neq 2$, and $d$ is large enough, ... More
Cooling mechanical oscillators by coherent controlAug 02 2016In optomechanics, electromagnetic fields are harnessed to control a single mode of a mechanically compliant system, while other mechanical degrees of freedom remain unaffected due to the modes' mutual orthogonality and high quality factor. Extension of ... More
Weyl type asymptotics and bounds for the eigenvalues of functional-difference operators for mirror curvesSep 30 2015Jan 10 2016We investigate Weyl type asymptotics of functional-difference operators associated to mirror curves of special del Pezzo Calabi-Yau threefolds. These operators are $H(\zeta)=U+U^{-1}+V+\zeta V^{-1}$ and $H_{m,n}=U+V+q^{-mn}U^{-m}V^{-n}$, where $U$ and ... More
Improved Decoding and Error Floor Analysis of Staircase CodesApr 06 2017Dec 03 2018Staircase codes play an important role as error-correcting codes in optical communications. In this paper, a low-complexity method for resolving stall patterns when decoding staircase codes is described. Stall patterns are the dominating contributor to ... More
Spanning Lattice Polytopes and the Uniform Position PrincipleNov 27 2017May 04 2018A lattice polytope $P$ is called IDP if any lattice point in its $k$th dilate is a sum of $k$ lattice points in $P$. In 1991 Stanley proved a strong inequality in Ehrhart theory for IDP lattice polytopes. We show that his conclusion holds under much milder ... More
Ehrhart Theory of Spanning Lattice PolytopesAug 10 2016Dec 04 2017A lattice polytope is called spanning if its lattice points affinely span the ambient lattice. We show as a corollary to a general result in the Ehrhart theory of lattice polytopes that the $h^*$-vector of a spanning lattice polytope has no gaps, i. e., ... More
When is a polynomial ideal binomial after an ambient automorphism?Jun 12 2017Can an ideal I in a polynomial ring k[x] over a field be moved by a change of coordinates into a position where it is generated by binomials $x^a - cx^b$ with c in k, or by unital binomials (i.e., with c = 0 or 1)? Can a variety be moved into a position ... More
Novel Feature-Based Clustering of Micro-Panel Data (CluMP)Jul 16 2018Micro-panel data are collected and analysed in many research and industry areas. Cluster analysis of micro-panel data is an unsupervised learning exploratory method identifying subgroup clusters in a data set which include homogeneous objects in terms ... More
Iterative Learning Control for Fast and Accurate Position Tracking with a Soft Robotic ArmJan 29 2019Feb 11 2019This paper presents an iterative learning control scheme to improve the position tracking performance for a soft robotic arm during aggressive maneuvers. Two antagonistically arranged, inflatable bellows actuate the robotic arm and provide high compliance ... More
Persistent accelerations disentangle Lagrangian turbulenceJan 28 2019Particles in turbulence frequently encounter extreme accelerations between extended periods of mild fluctuations. The occurrence of extreme events is closely related to the intermittent spatial distribution of intense flow structures. For example, vorticity ... More
Trigger for the SoLid Reactor Antineutrino ExperimentApr 16 2017SoLid, located at SCK-CEN in Mol, Belgium, is a reactor antineutrino experiment at a very short baseline of 5.5 -- 10m aiming at the search for sterile neutrinos and for high precision measurement of the neutrino energy spectrum of Uranium-235. It uses ... More
Archetypal Analysis for Sparse Representation-based Hyperspectral Sub-pixel QuantificationFeb 08 2018The estimation of land cover fractions from remote sensing images is a frequently used indicator of the environmental quality. This paper focuses on the quantification of land cover fractions in an urban area of Berlin, Germany, using simulated hyperspectral ... More