Results for "Wouter Cames van Batenburg"

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Strong cliques and forbidden cyclesMar 14 2019Given a graph $G$, the strong clique number $\omega_2'(G)$ of $G$ is the cardinality of a largest collection of edges every pair of which are incident or connected by an edge in $G$. We study the strong clique number of graphs missing some set of cycle ... More
The dimension of the Incipient Infinite ClusterMay 29 2014We study the Incipient Infinite Cluster (IIC) of high-dimensional bond percolation on $\mathbb{Z}^d$. We prove that the mass dimension of IIC almost surely equals $4$ and the volume growth exponent of IIC almost surely equals $2$.
Squared chromatic number without claws or large cliquesSep 27 2016Oct 25 2016Let $G$ be a claw-free graph on $n$ vertices with clique number $\omega$. We prove the following for the chromatic number $\chi(G^2)$ of the square $G^2$ of $G$. If $\omega\le 3$, then $\chi(G^2)\le 10$. If $\omega \le 4$, then $\chi(G^2) \le 22$. This ... More
The Bollobás-Eldridge-Catlin conjecture for even girth at least $10$Mar 15 2017Two graphs $G_1$ and $G_2$ on $n$ vertices are said to \textit{pack} if there exist injective mappings of their vertex sets into $[n]$ such that the images of their edge sets are disjoint. A longstanding conjecture due to Bollob\'as and Eldridge and, ... More
Packing graphs of bounded codegreeMay 18 2016Two graphs $G_1$ and $G_2$ on $n$ vertices are said to pack if there exist injective mappings of their vertex sets into $[n]$ such that the images of their edge sets are disjoint. A longstanding conjecture due to Bollob\'as and Eldridge and, independently, ... More
Squared chromatic number without claws or large cliquesSep 27 2016May 17 2018Let $G$ be a claw-free graph on $n$ vertices with clique number $\omega$, and consider the chromatic number $\chi(G^2)$ of the square $G^2$ of $G$. Writing $\chi'_s(d)$ for the supremum of $\chi(L^2)$ over the line graphs $L$ of simple graphs of maximum ... More
Squared chromatic and stability numbers without claws or large cliquesSep 27 2016Let $G$ be a claw-free graph on $n$ vertices with clique number $\omega$. We prove the following for the square $G^2$ of $G$. If $\omega\le 3$, then its chromatic number satisfies $\chi(G^2)\le 10$ while its stability number satisfies $\alpha(G^2)\ge ... More
Coloring Jordan regions and curvesAug 29 2016Sep 05 2016A Jordan region is a subset of the plane that is homeomorphic to a closed disk. Consider a family $\mathcal{F}$ of Jordan regions whose interiors are pairwise disjoint, and such that any two Jordan regions intersect in at most one point. If any point ... More
A tight Erdős-Pósa function for planar minorsJul 13 2018Nov 14 2018Let $H$ be a planar graph. By a classical result of Robertson and Seymour, there is a function $f:\mathbb{N} \to \mathbb{R}$ such that for all $k \in \mathbb{N}$ and all graphs $G$, either $G$ contains $k$ vertex-disjoint subgraphs each containing $H$ ... More
Bipartite induced density in triangle-free graphsAug 07 2018Aug 17 2018Any triangle-free graph on $n$ vertices with minimum degree at least $d$ contains a bipartite induced subgraph of minimum degree at least $d^2/(2n)$. This is sharp up to a logarithmic factor in $n$. We also provide a related extremal result for the fractional ... More
Information propagation and equilibration in long-range Kitaev chainsNov 17 2015We study the propagation of information through a Kitaev chain with long-range pairing interactions. Although the Lieb-Robinson bound is violated in the strict sense for long-range interacting systems, we illustrate that a major amount of information ... More
Prethermalization to thermalization crossover in a dilute Bose gas following an interaction rampMar 20 2018Jan 15 2019The dynamics of a weakly interacting Bose gas at low temperatures is close to integrable due to the approximate quadratic nature of the many-body Hamiltonian. While the short-time physics after an abrupt ramp of the interaction constant is dominated by ... More
The asymptotics of group Russian rouletteJul 14 2015May 01 2017We study the group Russian roulette problem, also known as the shooting problem, defined as follows. We have $n$ armed people in a room. At each chime of a clock, everyone shoots a random other person. The persons shot fall dead and the survivors shoot ... More
Spontaneous Beliaev-Landau scattering out of equilibriumApr 06 2017Dec 21 2017We investigate Beliaev-Landau scattering in a gas of interacting photons in a coherently driven array of nonlinear dissipative resonators, as described by the 1D driven-dissipative Bose-Hubbard model. Due to the absence of detailed balance in such an ... More
The higher rank $q$-deformed Bannai-Ito and Askey-Wilson algebraMay 17 2018The $q$-deformed Bannai-Ito algebra was recently constructed in the threefold tensor product of the quantum superalgebra $\mathfrak{osp}_q(1\vert 2)$. It turned out to be isomorphic to the Askey-Wilson algebra. In the present paper these results will ... More
Sparse and noisy LiDAR completion with RGB guidance and uncertaintyFeb 14 2019This work proposes a new method to accurately complete sparse LiDAR maps guided by RGB images. For autonomous vehicles and robotics the use of LiDAR is indispensable in order to achieve precise depth predictions. A multitude of applications depend on ... More
End-to-end Lane Detection through Differentiable Least-Squares FittingFeb 01 2019Lane detection is typically tackled with a two-step pipeline in which a segmentation mask of the lane markings is predicted first, and a lane line model (like a parabola or spline) is fitted to the post-processed mask next. The problem with such a two-step ... More
L'invariant de Suslin en caractéristique positiveJul 28 2009Pour une k-alg\`ebre simple centrale A d'indice inversible dans k, Suslin a d\'efini un invariant cohomologique de SK_1(A). Dans ce texte, nous g\'en\'eralisons cet invariant \`a toute k-alg\`ebre simple centrale par un rel\`evement de la caract\'eristique ... More
Quantifying the effects of data augmentation and stain color normalization in convolutional neural networks for computational pathologyFeb 18 2019Stain variation is a phenomenon observed when distinct pathology laboratories stain tissue slides that exhibit similar but not identical color appearance. Due to this color shift between laboratories, convolutional neural networks (CNNs) trained with ... More
Magnetic fields of AGB and post-AGB starsMar 13 2019There is ample evidence for strong magnetic fields in the envelopes of (Post-)Asymptotic Giant Branch (AGB) stars as well as supergiant stars. The origin and role of these fields are still unclear. This paper updates the current status of magnetic field ... More
Wave function Monte Carlo method for polariton condensatesMar 16 2012We present a quantum jump approach to describe coupled quantum and classical systems in the context of Bose-Einstein condensation in the solid state. In our formalism, the excitonic gain medium is described by classical rate equations, while the polariton ... More
Discretized Approaches to SchematizationJun 21 2016To produce cartographic maps, simplification is typically used to reduce complexity of the map to a legible level. With schematic maps, however, this simplification is pushed far beyond the legibility threshold and is instead constrained by functional ... More
Reducing the role of random numbers in matching algorithms for school admissionMar 13 2016New methods for solving the college admissions problem with indifference are presented and characterised with a Monte Carlo simulation in a variety of simple scenarios. Based on a qualifier defined as the average rank, it is found that these methods are ... More
Resolvent embeddingsOct 22 2013Feb 18 2014Many ex/reg completions $J:\mathcal C\to\mathcal C_{\rm ex/reg}$ that arise in categorical realizability and tripos theory admit left Kan extensions of arbitrary finitely continuous functors to arbitrary exact categories. This paper identifies the property ... More
Low-frequency vibrations of soft colloidal glassesMar 16 2010We conduct experiments on two-dimensional packings of colloidal thermosensitive hydrogel particles whose packing fraction can be tuned above the jamming transition by varying the temperature. By measuring displacement correlations between particles, we ... More
Dynamical quantum depletion in polariton condensatesJul 08 2015We present a theoretical study of the quantum depletion of microcavity polaritons that are excited with a resonant laser pulse. The dynamics of the quantum fluctuations are interpreted in the context of quantum quenches in general and in terms of the ... More
Single particle polariton properties in doped quantum well microcavities: role of the Fermi edge singularity and Anderson orthogonality catastropheApr 08 2014A theoretical investigation of the single particle polariton properties for a microcavity embedding a charged quantum well is presented. The electron gas optical susceptibility is calculated numerically using the method devised by Combescot and Nozi\`eres. ... More
A combinatorial interpretation for Schreyer's tetragonal invariantsOct 07 2014Jan 13 2015Schreyer has proved that the graded Betti numbers of a canonical tetragonal curve are determined by two integers $b_1$ and $b_2$, associated to the curve through a certain geometric construction. In this article we prove that in the case of a smooth projective ... More
The Synergy between VLBI and Gaia astrometryJan 23 2019Jan 31 2019With the publication of Gaia DR2, 1.3 billion stars now have public parallax and proper motion measurements. In this contribution, we compare the results for sources that have both optical and radio measurements, focusing on circumstellar masers. For ... More
An introduction to domain adaptation and transfer learningDec 31 2018Jan 14 2019In machine learning, if the training data is an unbiased sample of an underlying distribution, then the learned classification function will make accurate predictions for new samples. However, if the training data is not an unbiased sample, then there ... More
Polariton parametric photoluminescence in spatially inhomogeneous systemsNov 17 2008A general theory of polariton parametric photoluminescence in spatially inhomogeneous systems is developed. The quantum Langevin equations are solved in a generalized Bogoliubov de Gennes approximation. We apply the formalism to the specific case of a ... More
Experimental analysis of the accessibility of drawings with few segmentsAug 31 2017Sep 06 2018The visual complexity of a graph drawing is defined as the number of geometric objects needed to represent all its edges. In particular, one object may represent multiple edges, e.g., one needs only one line segment to draw two collinear incident edges. ... More
On the unsteady behavior of turbulence modelsSep 01 2010Periodically forced turbulence is used as a test case to evaluate the predictions of two-equation and multiple-scale turbulence models in unsteady flows. The limitations of the two-equation model are shown to originate in the basic assumption of spectral ... More
Embryonic Pattern Scaling Achieved by Oppositely Directed Morphogen GradientsJan 16 2006Morphogens are proteins, often produced in a localised region, whose concentrations spatially demarcate regions of differing gene expression in developing embryos. The boundaries of expression must be set accurately and in proportion to the size of the ... More
The Jet Shape at NLL$'$Jan 18 2019The jet shape is the fraction of the jet energy within a cone $r$ centered on the jet axis. We calculate the jet shape distribution at next-to-leading logarithmic accuracy plus next-to-leading order (NLL$'$), accounting for logarithms of both the jet ... More
Automatic alignment for three-dimensional tomographic reconstructionMay 24 2017Jan 17 2018In tomographic reconstruction, the goal is to reconstruct an unknown object from a collection of line integrals. Given a complete sampling of such line integrals for various angles and directions, explicit inverse formulas exist to reconstruct the object. ... More
A parametric level-set method for partially discrete tomographyApr 03 2017This paper introduces a parametric level-set method for tomographic reconstruction of partially discrete images. Such images consist of a continuously varying background and an anomaly with a constant (known) grey-value. We represent the geometry of the ... More
Towers of regular self-covers and linear endomorphisms of toriSep 21 2016Let $M$ be a closed manifold that admits a self-cover $p:M \to M$ of degree >1. We say p is strongly regular if all its iterates are regular covers. In this case, we establish an algebraic structure theorem for the fundamental group of $M$: We prove that ... More
Reduction of mean-square advection in turbulent passive scalar mixingJul 05 2011Jul 20 2012Direct numerical simulation data show that the variance of the coupling term in passive scalar advection by a random velocity field is smaller than it would be if the velocity and scalar fields were statistically independent. This effect is analogous ... More
Dynamics of coherent polaritons in double-well systemsNov 27 2007We investigate the physics of coherent polaritons in a double-well configuration under a resonant pumping. For a continuous wave pump, bistability and self-pulsing regimes are identified as a function of the pump energy and intensity. The response to ... More
Jet Charge at the LHCSep 11 2012Jun 14 2013Knowing the charge of the parton initiating a light-quark jet could be extremely useful both for testing aspects of the Standard Model and for characterizing potential beyond-the-Standard-Model signals. We show that despite the complications of hadronization ... More
Drawing Planar Graphs with Few Geometric PrimitivesMar 05 2017Sep 06 2018We define the \emph{visual complexity} of a plane graph drawing to be the number of basic geometric objects needed to represent all its edges. In particular, one object may represent multiple edges (e.g., one needs only one line segment to draw a path ... More
Studies Supporting PMT Characterization for the IceCube Collaboration: Precise Photodiode CalibrationNov 07 2015A laboratory set-up has been developed to more precisely measure the DOM optical sensitivity as a function of angle and wavelength. DOMs are calibrated in water using a broad beam of light whose intensity is measured with a NIST calibrated photodiode. ... More
Precision Analysis of Evolved StarsMar 12 2019Evolved stars dominate galactic spectra, enrich the galactic medium, expand to change their planetary systems, eject winds of a complex nature, produce spectacular nebulae and illuminate them, and transfer material between binary companions. While doing ... More
The fundamental theorem of affine geometry on toriDec 17 2016The classical Fundamental Theorem of Affine Geometry states that for $n\geq 2$, any bijection of $n$-dimensional Euclidean space that maps lines to lines (as sets) is given by an affine map. We consider an analogous characterization of affine automorphisms ... More
Learning an MR acquisition-invariant representation using Siamese neural networksOct 17 2018Generalization of voxelwise classifiers is hampered by differences between MRI-scanners, e.g. different acquisition protocols and field strengths. To address this limitation, we propose a Siamese neural network (MRAI-NET) that extracts acquisition-invariant ... More
Rigidity of convex divisible domains in flag manifoldsOct 14 2015In contrast to the many examples of convex divisible domains in real projective space, we prove that up to projective isomorphism there is only one convex divisible domain in the Grassmannian of $p$-planes in $\mathbb{R}^{2p}$ when $p > 1$. Moreover, ... More
The density matrix renormalization group for ab initio quantum chemistryJul 08 2014During the past 15 years, the density matrix renormalization group (DMRG) has become increasingly important for ab initio quantum chemistry. Its underlying wavefunction ansatz, the matrix product state (MPS), is a low-rank decomposition of the full configuration ... More
Negative drag in nonequilibrium polariton quantum fluidsDec 17 2013The possibility of a negative drag force on a defect in nonequilibrium polariton quantum fluids is presented. We relate this phenomenon to the selective parametric amplification of the waves scattered by the defect. This leads to the prediction that mobile ... More
Barrier efficiency of sponge-like La2Zr2O7 buffer layers for YBCO-coated conductorsMar 30 2011Solution derived La2Zr2O7 films have drawn much attention for potential applications as thermal barriers or low-cost buffer layers for coated conductor technology. Annealing and coating parameters strongly affect the microstructure of La2Zr2O7, but different ... More
Rapid seismic domain transfer: Seismic velocity inversion and modeling using deep generative neural networksMay 22 2018Traditional physics-based approaches to infer sub-surface properties such as full-waveform inversion or reflectivity inversion are time-consuming and computationally expensive. We present a deep-learning technique that eliminates the need for these computationally ... More
Precision astrometry of pulsars and other compact radio sources in the globular cluster M15Mar 27 2014The globular cluster (GC) M15 (NGC 7078) is host to at least eight pulsars and two low mass X-ray binaries (LMXBs) one of which is also visible in the radio regime. Here we present the results of a multi-epoch global very long baseline interferometry ... More
MetaGrad: Multiple Learning Rates in Online LearningApr 29 2016Nov 01 2016In online convex optimization it is well known that certain subclasses of objective functions are much easier than arbitrary convex functions. We are interested in designing adaptive methods that can automatically get fast rates in as many such subclasses ... More
A discrete realization of the higher rank Racah algebraAug 21 2018In previous work a higher rank generalization $R(n)$ of the Racah algebra was defined abstractly. The special case of rank one encodes the bispectrality of the univariate Racah polynomials and is known to admit an explicit realization in terms of the ... More
Freezing and Sleeping: Tracking Experts that Learn by Evolving Past PosteriorsAug 27 2010A problem posed by Freund is how to efficiently track a small pool of experts out of a much larger set. This problem was solved when Bousquet and Warmuth introduced their mixing past posteriors (MPP) algorithm in 2001. In Freund's problem the experts ... More
Pattern theorems, ratio limit theorems and Gumbel maximal clusters for random fieldsMay 31 2007We study occurrences of patterns on clusters of size n in random fields on Z^d. We prove that for a given pattern, there is a constant a>0 such that the probability that this pattern occurs at most an times on a cluster of size n is exponentially small. ... More
Selective Jamming of LoRaWAN using Commodity HardwareDec 06 2017Long range, low power networks are rapidly gaining acceptance in the Internet of Things (IoT) due to their ability to economically support long-range sensing and control applications while providing multi-year battery life. LoRa is a key example of this ... More
Crawling and turning in a minimal reaction-diffusion cell motility model: coupling cell shape and biochemistrySep 06 2016We study a minimal model of a crawling eukaryotic cell with a chemical polarity controlled by a reaction-diffusion mechanism describing Rho GTPase dynamics. The size, shape, and speed of the cell emerge from the combination of the chemical polarity, which ... More
Translating between the roots of the identity in quantum computersMar 30 2015Oct 22 2015The Clifford+$T$ quantum computing gate library for single qubit gates can create all unitary matrices that are generated by the group $\langle H, T\rangle$. The matrix $T$ can be considered the fourth root of Pauli $Z$, since $T^4 = Z$ or also the eighth ... More
A high aspect ratio Fin-Ion Sensitive Field Effect Transistor: compromises towards better electrochemical bio-sensingJan 08 2019The development of next generation medicines demand more sensitive and reliable label free sensing able to cope with increasing needs of multiplexing and shorter times to results. Field effect transistor-based biosensors emerge as one of the main possible ... More
A cross-center smoothness prior for variational Bayesian brain tissue segmentationMar 11 2019Suppose one is faced with the challenge of tissue segmentation in MR images, without annotators at their center to provide labeled training data. One option is to go to another medical center for a trained classifier. Sadly, tissue classifiers do not ... More
Rigidity of warped cones and coarse geometry of expandersOct 09 2017Jan 06 2018We study the geometry of warped cones over free, minimal isometric group actions and related constructions of expander graphs. We prove a rigidity theorem for the coarse geometry of such warped cones: Namely, if a group has no abelian factors, then two ... More
Stochastic Beams and Where to Find Them: The Gumbel-Top-k Trick for Sampling Sequences Without ReplacementMar 14 2019The well-known Gumbel-Max trick for sampling from a categorical distribution can be extended to sample $k$ elements without replacement. We show how to implicitly apply this 'Gumbel-Top-$k$' trick on a factorized distribution over sequences, allowing ... More
Second-order Quantile Methods for Experts and Combinatorial GamesFeb 27 2015We aim to design strategies for sequential decision making that adjust to the difficulty of the learning problem. We study this question both in the setting of prediction with expert advice, and for more general combinatorial decision tasks. We are not ... More
Switching between Hidden Markov Models using Fixed ShareAug 26 2010In prediction with expert advice the goal is to design online prediction algorithms that achieve small regret (additional loss on the whole data) compared to a reference scheme. In the simplest such scheme one compares to the loss of the best expert in ... More
Approximate Dynamic Programming with Neural Networks in Linear Discrete Action SpacesFeb 26 2019Real-world problems of operations research are typically high-dimensional and combinatorial. Linear programs are generally used to formulate and efficiently solve these large decision problems. However, in multi-period decision problems, we must often ... More
Attention, Learn to Solve Routing Problems!Mar 22 2018Feb 07 2019The recently presented idea to learn heuristics for combinatorial optimization problems is promising as it can save costly development. However, to push this idea towards practical implementation, we need better models and better ways of training. We ... More
Jammed frictionless discs: connecting local and global responseNov 04 2009By calculating the linear response of packings of soft frictionless discs to quasistatic external perturbations, we investigate the critical scaling behavior of their elastic properties and non-affine deformations as a function of the distance to jamming. ... More
Periodic migration in a physical model of cells on micropatternsOct 01 2013We extend a model for the morphology and dynamics of a crawling eukaryotic cell to describe cells on micropatterned substrates. This model couples cell morphology, adhesion, and cytoskeletal flow in response to active stresses induced by actin and myosin. ... More
Arbor -- a morphologically-detailed neural network simulation library for contemporary high-performance computing architecturesJan 17 2019We introduce Arbor, a performance portable library for simulation of large networks of multi-compartment neurons on HPC systems. Arbor is open source software, developed under the auspices of the HBP. The performance portability is by virtue of back-end ... More
$\boldsymbol{C\!P}\!$ violation in Higgs--gauge interactions: from tabletop experiments to the LHCMar 08 2019We investigate $C\!P$-violating interactions involving gauge bosons and the Higgs boson within an effective field theory approach, focusing on the six couplings that define the $C\!P$-violating sector of so-called universal theories. We compute the contributions ... More
DMRG-CASPT2 study of the longitudinal static second hyperpolarizability of all-trans polyenesMay 18 2016Jul 13 2016We have implemented internally contracted complete active space second order perturbation theory (CASPT2) with the density matrix renormalization group (DMRG) as active space solver [Y. Kurashige and T. Yanai, J. Chem. Phys. 135, 094104 (2011)]. Internally ... More
Central limit theorems for random polytopes in a smooth convex setMar 24 2005Let $K$ be a smooth convex set with volume one in $\BBR^d$. Choose $n$ random points in $K$ independently according to the uniform distribution. The convex hull of these points, denoted by $K_n$, is called a {\it random polytope}. We prove that several ... More
CheMPS2: a free open-source spin-adapted implementation of the density matrix renormalization group for ab initio quantum chemistryDec 09 2013Jan 08 2014The density matrix renormalization group (DMRG) has become an indispensable numerical tool to find exact eigenstates of finite-size quantum systems with strong correlation. In the fields of condensed matter, nuclear structure and molecular electronic ... More
Astrometry of the OH masers of 4 Mira starsSep 16 2003The OH main line masers in circumstellar shells were observed with astrometric VLBI in order to accurately determine the position of the star, as well as its motion, including the parallax. Results are presented on 4 Mira stars monitored for 2 - 8 years ... More
Quasicircle boundaries and exotic almost-isometriesSep 30 2014We consider properly discontinuous, isometric, convex cocompact actions of surface groups on a CAT(-1) space. We show that the limit set of such an action, equipped with the canonical visual metric, is a (weak) quasicircle in the sense of Falconer and ... More
Companding technique for high dynamic range measurements using gafchromic filmsJul 20 2011We propose a methodology to perform dose measurements using gafchromic films which can span several decades of dose levels. The technique is based on a rescaling approach using different films irradiated at different dose levels. This is combined with ... More
Stacked Penalized Logistic Regression for Selecting Views in Multi-View LearningNov 06 2018Feb 07 2019In biomedical research many different types of patient data can be collected, including various types of omics data and medical imaging modalities. Applying multi-view learning to these different sources of information can increase the accuracy of medical ... More
Lipschitz Adaptivity with Multiple Learning Rates in Online LearningFeb 27 2019We aim to design adaptive online learning algorithms that take advantage of any special structure that might be present in the learning task at hand, with as little manual tuning by the user as possible. A fundamental obstacle that comes up in the design ... More
A type system for Continuation CalculusSep 11 2014Continuation Calculus (CC), introduced by Geron and Geuvers, is a simple foundational model for functional computation. It is closely related to lambda calculus and term rewriting, but it has no variable binding and no pattern matching. It is Turing complete ... More
The asymptotics of group Russian rouletteJul 14 2015We study the group Russian roulette problem, also known as the shooting problem, defined as follows. We have $n$ armed people in a room. At each chime of a clock, everyone shoots a random other person. The persons shot fall dead and the survivors shoot ... More
Weakly nonlocal continuum physics - the Ginzburg-Landau equationOct 18 2002May 13 2003Some peculiarities of the exploitation of the entropy inequality in case of weakly nonlocal continuum theories are investigated and refined. As an example it is shown that the proper application of the Liu procedure leads to the Ginzburg-Landau equation ... More
Weakly nonlocal continuum theories of granular media: restrictions from the Second LawOct 22 2003Nov 07 2003The classical continuum mechanical model of granular media of rational thermodynamics results in a Coulomb-Mohr type equilibrium stress-strain relation. The proof is based on a two component material model introducing a scalar internal variable. Here ... More
Weakly nonlocal irreversible thermodynamicsDec 12 2001Jan 10 2003Weakly nonlocal thermodynamic theories are critically revisited. A relocalized, irreversible thermodynamic theory of nonlocal phenomena is given, based on a modified form of the entropy current and new kind of internal variables, the so called current ... More
Potentials of Mean Force for Protein Structure Prediction Vindicated, Formalized and GeneralizedAug 24 2010Nov 23 2010Understanding protein structure is of crucial importance in science, medicine and biotechnology. For about two decades, knowledge based potentials based on pairwise distances -- so-called "potentials of mean force" (PMFs) -- have been center stage in ... More
A number theoretic question arising in the geometry of plane curves and in billiard dynamicsMar 25 2011We prove that if $\rho\neq1/2$ is a rational number between zero and one, then there is no integer $n>1$ such that $$ n\tan(\pi\rho)=\tan(n\pi\rho). $$ This has interpretations both in the theory of bicycle curves and that of mathematical billiards.
DMRG-SCF study of the singlet, triplet, and quintet states of oxo-Mn(Salen)May 22 2014Jun 18 2014We use CheMPS2, our free open-source spin-adapted implementation of the density matrix renormalization group (DMRG) [Wouters et al., Comput. Phys. Commun. 185, 1501 (2014)], to study the lowest singlet, triplet, and quintet states of the oxo-Mn(Salen) ... More
A Parallel-pulling Protocol for Free-Energy EvaluationMay 24 2011Feb 14 2012Jarzynski's equality (JE) allows us to compute free energy differences from distributions of work. In molecular dynamics simulations, the traditional way of constructing work distributions is to perform as many pulling simulations as possible. But reliable ... More
Combining Adversarial Guarantees and Stochastic Fast Rates in Online LearningMay 20 2016We consider online learning algorithms that guarantee worst-case regret rates in adversarial environments (so they can be deployed safely and will perform robustly), yet adapt optimally to favorable stochastic environments (so they will perform well in ... More
Counting publications and citations: Is more always better?Jan 19 2013Apr 02 2013Is more always better? We address this question in the context of bibliometric indices that aim to assess the scientific impact of individual researchers by counting their number of highly cited publications. We propose a simple model in which the number ... More
Gafchromic film dosimetry: calibration methodology and error analysisJul 19 2011Purpose : To relate the physical transmittance parameters of the water equivalent Gafchromic EBT 2 Film with the delivered dose in a transparent absolute calibration protocol. The protocol should be easy to understand, easy to perform, and should be able ... More
The elephant in the room: The problem of quantifying productivity in evaluative scientometricsMay 08 2016In a critical and provocative paper, Abramo and D'Angelo claim that commonly used scientometric indicators such as the mean normalized citation score (MNCS) are completely inappropriate as indicators of scientific performance. Abramo and D'Angelo argue ... More
Probing the collective excitations of a spinor polariton fluidNov 04 2014Feb 23 2015We propose a pump-probe set-up to analyse the properties of the collective excitation spectrum of a spinor polariton fluid. By using a linear response approximation scheme, we carry on a complete classification of all excitation spectra, as well as their ... More
Stochastic domination and weak convergence of conditioned Bernoulli random vectorsSep 27 2011For n>=1 let X_n be a vector of n independent Bernoulli random variables. We assume that X_n consists of M "blocks" such that the Bernoulli random variables in block i have success probability p_i. Here M does not depend on n and the size of each block ... More
An Algebraic Framework for Discrete Tomography: Revealing the Structure of DependenciesJun 03 2009Jul 30 2009Discrete tomography is concerned with the reconstruction of images that are defined on a discrete set of lattice points from their projections in several directions. The range of values that can be assigned to each lattice point is typically a small discrete ... More
Magnetic field in a young circumbinary diskMay 01 2018Aug 06 2018We use polarization observations of a circumbinary disk to investigate how the polarization properties change at distinct frequency bands. Our goal is to discern the main mechanism responsible for the polarization through comparison between our observations ... More
The Unexpected Spectrum of the Innermost Ejecta of the Red Hypergiant VY CMaMar 20 2019HST/STIS spectra of the small clumps and filaments closest to the central star in VY CMa reveal that the very strong K I emission and TiO and VO molecular emission, long thought to form in a dusty circumstellar shell, actually originate in a few small ... More
Phenomenology of the trilinear Higgs coupling at proton-proton collidersAug 21 2014Sep 18 2014We investigate Higgs pair production at proton-proton colliders, with emphasis on the gluon fusion channel at the HL-LHC. We study the behaviour of the leading order matrix element using exact computation of quark loops and infinite quark mass approximation. ... More
The Painter's Problem: covering a grid with colored connected polygonsAug 30 2017Motivated by a new way of visualizing hypergraphs, we study the following problem. Consider a rectangular grid and a set of colors $\chi$. Each cell $s$ in the grid is assigned a subset of colors $\chi_s \subseteq \chi$ and should be partitioned such ... More
Extensive v2DM study of the one-dimensional Hubbard model for large lattice sizes: Exploiting translational invariance and parityMar 01 2013Using variational density matrix optimization with two- and three-index conditions we study the one-dimensional Hubbard model with periodic boundary conditions at various filling factors. Special attention is directed to the full exploitation of the available ... More