Results for "F. Niel"

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From quantum to classical modelling of radiation reaction: a focus on the radiation spectrumFeb 08 2018Soon available multi petawatt ultra-high-intensity (UHI) lasers will allow us to probe high-amplitude electromagnetic fields interacting with either ultra-relativistic electron beams or hot plasmas in the so-called moderately quantum regime. The correct ... More
Measuring Resonance Parameters of Heavy Higgs Bosons at TESLAAug 13 2003This study investigates the potential of the TESLA Linear Collider for measuring resonance parameters of Higgs bosons beyond the mass range studied so far. The analysis is based on the reconstruction of events from the Higgsstrahlung process e+e- -> HZ. ... More
Moving frames applied to shell elasticityJul 19 2006Exterior calculus and moving frames are used to describe curved elastic shells. The kinematics follow from the Lie-derivative on forms whereas the dynamics via stress-forms.
A relative Shafarevich theoremApr 08 2002Suppose given a Galois etale cover Y -> X of proper non-singular curves over an algebraically closed field k of prime characteristic p. Let H be its Galois group, and G any finite extension of H by a p-group P. We give necessary and sufficient conditions ... More
Density of quasismooth hypersurfaces in simplicial toric varietiesSep 23 2014Mar 23 2016This paper investigates the density of hypersurfaces in a projective normal simplicial toric variety over a finite field having a quasismooth intersection with a given quasismooth subscheme. The result generalizes the formula found by B. Poonen for smooth ... More
Fundamental gerbesOct 24 2016For a class of affine algebraic groups $\mathcal C$ over a field, we define the notions of $\mathcal C$-fundamental gerbe of a fibered category, generalizing what we had done in arXiv:1204.1260 for finite group schemes. We give sufficient conditions on ... More
The cyclic theory of Hopf algebroidsApr 30 2009May 29 2010We give a systematic description of the cyclic cohomology theory of Hopf algebroids in terms of its associated category of modules. Then we introduce a dual cyclic homology theory by applying cyclic duality to the underlying cocyclic object. We derive ... More
On the Taut String Interpretation of the One-dimensional Rudin-Osher-Fatemi Model: A New Proof, a Fundamental Estimate and Some ApplicationsOct 27 2017A new proof of the equivalence of the Taut String Algorithm and the one-dimensional Rudin-Osher-Fatemi model is presented. Based on duality and the projection theorem in Hilbert space, the proof is strictly elementary. Existence and uniqueness of solutions ... More
On computation with 'probabilities' modulo kMay 28 2014Dec 23 2014We propose a framework to study models of computation of indeterministic data, represented by abstract "distributions". In these distributions, probabilities are replaced by "amplitudes" drawn from a fixed semi-ring $S$, of which the non-negative reals, ... More
A Note on Unconditional Structures in Weak Hilbert SpacesApr 24 1992We prove that if a non-atomic separable Banach lattice in a weak Hilbert space, then it is lattice isomorphic to $L_2(0,1)$.
Compliance of POLYAS with the Common Criteria Protection ProfileDec 19 2010Dec 21 2010In 2008, the German Federal Office for Information Security issued the common criteria protection profile for Online Voting Products (PP-0037). Accord- ingly, we evaluated the Polyas electronic voting system, which is used for legally binding elections ... More
Un critère d'épointage des sections $l$-adiquesJan 22 2012Jan 21 2013The cuspidalization conjecture emerged as an approach of Grothendieck's famous section conjecture. We address a weak form of it by using a mild generalization of a theorem of Uwe Jannsen which describes exactly when the $l$-adic homology of an open curve ... More
Amenability of algebras of approximable operatorsApr 10 2008We give a necessary and sufficient condition for amenability of the Banach algebra of approximable operators on a Banach space. We further investigate the relationship between amenability of this algebra and factorization of operators, strengthening known ... More
Brownian Motion after Einstein: Some new applications and new experimentsMar 17 2006The first half of this chapter describes the development in mathematical models of Brownian motion after Einstein's seminal papers and current applications to optical tweezers. This instrument of choice among single-molecule biophysicists is also an instrument ... More
The unreasonable accuracy of the Jastrow approach in many-body physicsJul 14 2003We investigate in a simple model whether a Jastrow-based approach for a many-body system containing two-body interactions can be exact. By comparison with recent assertions to the contrary, we find that in general the exact wave function is \emph{not} ... More
Universal dynamics in the onset of a Hagen-Poiseuille flowNov 07 2005Jun 09 2006The dynamics in the onset of a Hagen-Poiseuille flow of an incompressible liquid in a channel of circular cross section is well-studied theoretically. We use an eigenfunction expansion in a Hilbert space formalism to generalize the results to channels ... More
Some distance bounds of branching processes and their diffusion limitsMay 20 2010We compute exact values respectively bounds of "distances" - in the sense of (transforms of) power divergences and relative entropy - between two discrete-time Galton-Watson branching processes with immigration GWI for which the offspring as well as the ... More
Vassiliev Invariants from Symmetric SpacesOct 23 2014We construct a natural framed weight system on chord diagrams from the curvature tensor of any pseudo-Riemannian symmetric space. These weight systems are of Lie algebra type and realized by the action of the holonomy Lie algebra on a tangent space. Among ... More
On the nature of the phase transitions in two-dimensional type II superconductorsJun 05 2013Aug 27 2013We have simulated the thermodynamics of vortices in a thin film of a type-II superconductor. We make the lowest Landau level approximation, and use quasi-periodic boundary conditions. Our work is consistent with the results of previous simulations where ... More
Mean-field Evolution of Fermionic SystemsMay 13 2013Oct 08 2013The mean field limit for systems of many fermions is naturally coupled with a semiclassical limit. This makes the analysis of the mean field regime much more involved, compared with bosonic systems. In this paper, we study the dynamics of initial data ... More
Phase Space Reduction of Star Products on Cotangent BundlesMar 15 2004In this paper we construct star products on Marsden-Weinstein reduced spaces in case both the original phase space and the reduced phase space are (symplectomorphic to) cotangent bundles. Under the assumption that the original cotangent bundle $T^*Q$ ... More
Optomechanical Self-Oscillations in an Anharmonic Potential: Engineering a Nonclassical Steady StateJun 03 2016We study self-oscillations of an optomechanical system, where coherent mechanical oscillations are induced by a driven optical or microwave cavity, for the case of an anharmonic mechanical oscillator potential. A semiclassical analytical model is developed ... More
Achieving Anisotropy in Metamaterials made of Dielectric Cylindrical RodsJun 03 2010We show that anisotropic negative effective dispersion relation can be achieved in pure dielectric rod-type metamaterials by turning from the symmetry of a square lattice to that of a rectangular one, i.e. by breaking the rotation symmetry of effective ... More
Hartree-Fock dynamics for weakly interacting fermionsApr 30 2014We review recent results concerning the evolution of fermionic systems. We are interested in the mean field regime, where particles experience many weak collisions. For fermions, the mean field regime is naturally linked with a semiclassical limit. Assuming ... More
Non-compact families of complete, properly immersed minimal immersions with fixed topology via desingularizationSep 30 2014For fixed large genus, we construct families of complete immersed minimal surfaces in R3 with four ends and dihedral symmetries. The families exist for all large genus and at an appropriate scale degenerate to the plane.
A singular, admissible extension which splits algebraically, but not strongly, of the algebra of bounded operators on a Banach spaceMar 14 2016Let $E$ be the Banach space constructed by Read (J. London Math. Soc. 1989) such that the Banach algebra $\mathscr{B}(E)$ of bounded operators on $E$ admits a discontinuous derivation. We show that $\mathscr{B}(E)$ has a singular, admissible extension ... More
Assumptions and Axioms: Mathematical Structures to Describe the Physics of Rigid BodiesMay 05 2010This paper challenges some of the common assumptions underlying the mathematics used to describe the physical world. We start by reviewing many of the assumptions underlying the concepts of real, physical, rigid bodies and the translational and rotational ... More
Reconstructing signals from noisy data with unknown signal and noise covarianceJul 12 2011Sep 28 2011We derive a method to reconstruct Gaussian signals from linear measurements with Gaussian noise. This new algorithm is intended for applications in astrophysics and other sciences. The starting point of our considerations is the principle of minimum Gibbs ... More
Recent Results from HEGRA (Gamma-Ray Observations with the HEGRA Stereoscopic System of 5 Cherenkov Telescopes)Oct 10 2003The HEGRA collaboration has achieved outstanding results during the operation of the six imaging atmospheric Cherenkov telescopes from 1996 to 2002. The experimental work pioneered the field of TeV gamma-ray astronomy with observations during partial ... More
Nonlinear photonic crystal fibres: pushing the zero-dispersion toward the visibleAug 14 2006The strong waveguide dispersion in photonic crystal fibres provides unique opportunities for nonlinear optics with a zero-dispersion wavelength $\lambda_0$ far below the limit of ~1.3 micron set by the material dispersion of silica. By tuning the air-hole ... More
A general algorithm for calculation of recombination losses in ionization chambers exposed to ion beamsOct 21 2016Dosimetry with ionization chambers in clinical ion beams for radiation therapy requires correction for recombination effects. However, common radiation protocols discriminate between initial and general recombination and provide no universal correction ... More
Penalized estimation in large-scale generalized linear array modelsOct 12 2015Sep 02 2016Large-scale generalized linear array models (GLAMs) can be challenging to fit. Computation and storage of its tensor product design matrix can be impossible due to time and memory constraints, and previously considered design matrix free algorithms do ... More
Factorization of the identity through operators with large diagonalSep 10 2015Given a Banach space $X$ with an unconditional basis, we consider the following question: does the identity on $X$ factor through every bounded operator on $X$ with large diagonal relative to the unconditional basis? We show that on Gowers' space with ... More
Lifting Galois sections along torsorsJan 18 2013Aug 17 2015The cuspidalization conjecture, which is a consequence of Grothendieck's section conjecture, asserts that for any smooth hyperbolic curve $X$ over a finitely generated field $k$ of characteristic $0$ and any non empty Zariski open $U \subset X$, every ... More
A Semiparametric Model for Bayesian Reader IdentificationJul 18 2016We study the problem of identifying individuals based on their characteristic gaze patterns during reading of arbitrary text. The motivation for this problem is an unobtrusive biometric setting in which a user is observed during access to a document, ... More
Cohomology of G-sheaves in positive characteristicDec 19 2002Apr 13 2003Let X be a noetherian scheme defined over an algebraically closed field of positive characteristic p, and G be a finite group, of order divisible by p, acting on X. We introduce a refinement of the equivariant K-theory of X to take into account the information ... More
Photonic nanowire-based single-photon source with polarization controlMay 23 2016This document describes a modal method for optical simulations of structures with elliptical cross sections and its application to the design of the photonic nanowire (NW)-based single-photon source (SPS). The work was carried out in the framework of ... More
Self force on a scalar charge in Kerr spacetime: inclined circular orbitsAug 13 2014Feb 02 2015Accurately modeling astrophysical extreme-mass-ratio-insprials requires calculating the gravitational self-force for orbits in Kerr spacetime. The necessary calculation techniques are typically very complex and, consequently, toy scalar-field models are ... More
The distribution of quantum fidelitiesJul 30 2008When applied to different input states, an imperfect quantum operation yields output states with varying fidelities, defined as the absolute square of their overlap with the desired states. We present an expression for the distribution of fidelities for ... More
Fidelity of quantum operationsJan 19 2007Feb 05 2007We present a derivation and numerous applications of a compact explicit formula for the average fidelity of a quantum operation on a finite dimensional quantum system. The formula can be applied to averages over particularly relevant subspaces; it is ... More
A discrete random model describing bedrock profile abrasionJul 13 2011We use a simple, collision-based, discrete, random abrasion model to compute the profiles for the stoss faces in a bedrock abrasion process. The model is the discrete equivalent of the generalized version of a classical, collision based model of abrasion. ... More
Robust quantum optimizer with full connectivitySep 20 2016Quantum phenomena have the potential to speed up the solution of hard optimization problems. For example quantum annealing, based on the quantum tunneling effect, has recently been shown to scale exponentially better with system size as compared with ... More
Varying-coefficient models with isotropic Gaussian process priorsAug 28 2015Oct 14 2015We study learning problems in which the conditional distribution of the output given the input varies as a function of additional task variables. In varying-coefficient models with Gaussian process priors, a Gaussian process generates the functional relationship ... More
Families of circles on surfacesFeb 27 2013Jan 01 2014We classify surfaces in 3-space that carry at least 2 families of real circles. Equivalently, we classify surfaces with at least 2 real circles through a generic closed point. We call such surfaces real celestials. We show that celestials are weak Del ... More
A rigidity result for crossed products of actions of Baumslag-Solitar groupsSep 29 2015Nov 01 2015Let BS(n_1,m_1) $\curvearrowright$ X_1 and BS(n_2,m_2) $\curvearrowright$ X_2 be two ergodic essentially free probability measure preserving actions of nonamenable Baumslag-Solitar groups whose canonical almost normal abelian subgroups act aperiodically. ... More
Gerstenhaber and Batalin-Vilkovisky structures on modules over operadsDec 05 2013Jan 22 2015In this article, we show under what additional ingredients a comp (or opposite) module over an operad with multiplication can be given the structure of a cyclic k-module and how the underlying simplicial homology gives rise to a Batalin-Vilkovisky module ... More
Minimal families of curves on surfacesFeb 27 2013Jan 06 2014A minimal family of curves on an embedded surface is defined as a 1-dimensional family of rational curves of minimal degree, which cover the surface. We classify such minimal families using constructive methods. This allows us to compute the minimal families ... More
Embeddings of homogeneous spaces in prime characteristicsFeb 16 1995Let $G$ be a reductive linear algebraic group. The simplest example of a projective homogeneous $G$-variety in characteristic $p$, not isomorphic to a flag variety, is the divisor $x_0 y_0^p+x_1 y_1^p+x_2 y_2^p=0$ in $P^2\times P^2$, which is $SL_3$ modulo ... More
Bounded Hochschild cohomology of Banach algebras with a matrix-like structureNov 28 2003Let B be a unital Banach algebra. A projection in B which is equivalent to the identitity may give rise to a matrix-like structure on any two-sided ideal A in B. In this set-up we prove a theorem to the effect that the bounded Hochschild cohomology H^n(A,A^*) ... More
Reconstruction of Gaussian and log-normal fields with spectral smoothnessOct 25 2012Mar 13 2013We develop a method to infer log-normal random fields from measurement data affected by Gaussian noise. The log-normal model is well suited to describe strictly positive signals with fluctuations whose amplitude varies over several orders of magnitude. ... More
Interactions Between Charged Rods Near Salty SurfacesOct 15 1999Nov 17 1999Using both theoretical modeling and computer simulations we study a model system for DNA interactions in the vicinity of charged membranes. We focus on the polarization of the mobile charges in the membranes due to the nearby charged rods (DNA) and the ... More
Truncated Groebner fans and lattice idealsSep 11 2005We outline a generalization of the Groebner fan of a homogeneous ideal with maximal cells parametrizing truncated Groebner bases. This "truncated" Groebner fan is usually much smaller than the full Groebner fan and offers the natural framework for conversion ... More
Self-induced Banach algebrasNov 28 2003A Banach algebra A is self-induced if the multiplication is an isomorphism from the A-balanced projective tensor-square of A to A. The class of self-induced Banach algebras is a natural generalization of unital Banach algebras, providing a fertile framework ... More
The passive and active periods for the intermittent use of an active sensor to detect an evasive targetDec 18 2013Your task is to detect a submarine with your active sonar. The submarine can hear your active sonar before you can detect him. If the submarine is fast enough he can evade you before you can detect him. How do you then detect him? If you are using your ... More
A degree bound for families of rational curves on surfacesFeb 11 2014Sep 10 2015We give an upper bound for the degree of rational curves in a family that covers a given birational ruled surface in projective space. The upper bound is stated in terms of the degree, sectional genus and arithmetic genus of the surface. We introduce ... More
Clifford and Euclidean translations of circlesJun 08 2013Jul 13 2015Celestials are surfaces that contain at least two real circles through a general point. We present a partial classification of celestials in the three-sphere up to Moebius equivalence. In particular, we consider translational celestials, which are the ... More
When Ext is a Batalin-Vilkovisky algebraOct 04 2016We show under what conditions the complex computing general Ext-groups carries the structure of a cyclic operad such that Ext becomes a Batalin-Vilkovisky algebra. This is achieved by transferring cyclic cohomology theories for the dual of a (left) Hopf ... More
Sur les représentations du groupe fondamental d'une variété privée d'un diviseur à croisements normaux simplesApr 10 2007Feb 15 2008Given a projective variety X over an algebraically closed field of characteristic zero, we show that finite parabolic bundles along a fixed simple normal crossings divisor D are in one to one correspondence with representations of the \'etale fundamental ... More
Push-outs of derivationsApr 10 2008Let A be a Banach algebra and let X be a Banach A -bimodule. In studying the bounded Hochschild cohomology groups H^1(A,X) it is often useful to extend a given derivation D: A-> X to a Banach algebra B containing A as an ideal, thereby exploiting (or ... More
Hypersurfaces with defectOct 13 2016A projective hypersurface $X \subseteq \mathbb P^n$ has defect if $h^i(X) \neq h^i(\mathbb P^n)$ for some $i \in \{n, \dots, 2n-2\}$ in a suitable cohomology theory. This occurs for example when $X \subseteq \mathbb P^4$ is not $\mathbb Q$-factorial. ... More
Fibrés paraboliques et champ des racinesApr 20 2006Following ideas of Nori, Biswas, ..., we show that given an integer r>0, a noetherian scheme X, and an effective Cartier divisor D on it, the parabolic vector bundles on (X,D) with weights multiples of 1/r (in the sense of Maruyama-Yokogawa) are equivalent ... More
Interpreting the von Neumann entropy of graph Laplacians, and coentropic graphsApr 30 2013For any graph, we define a rank-1 operator on a bipartite tensor product space, with components associated to the set of vertices and edges respectively. We show that the partial traces of the operator are the Laplacian and the edge-Laplacian. This provides ... More
Observations of short-duration X-ray transients by WATCH on GranatMay 06 1999During 1990-92, the WATCH all-sky X-ray monitor on Granat discovered six short-duration X-ray transients. In this paper we discuss their possible relationship to peculiar stars. Only one of the fast (few hours) X-ray transients (GRS 1100-771) might be ... More
Factorization and weak amenability of A(X)Nov 28 2003We investigate weak amenability of the Banach algebra A(X) of approximable operators on a Banach space X and its relation to factorization properties of operators in A(X). We show that if A(X) is weakly amenable, then either A(X) is self-induced (a nice ... More
Fast, Compact, and High Quality LSTM-RNN Based Statistical Parametric Speech Synthesizers for Mobile DevicesJun 20 2016Jun 22 2016Acoustic models based on long short-term memory recurrent neural networks (LSTM-RNNs) were applied to statistical parametric speech synthesis (SPSS) and showed significant improvements in naturalness and latency over those based on hidden Markov models ... More
Families of bitangent planes of space curves and minimal non-fibration familiesFeb 27 2013Jan 06 2014We define a cone curve to be a reduced sextic space curve which lies on a quadric cone and does not go through the vertex. We classify families of bitangent planes of cone curves. The methods we apply can be used for any space curve with ADE singularities, ... More
Interaction Corrections to Spin-Wave Theory in the Large-S Limit of the Quantum Heisenberg FerromagnetApr 09 2016Oct 04 2016The Quantum Heisenberg Ferromagnet can be naturally reformulated in terms of interacting bosons (called spin waves or magnons) as an expansion in the inverse spin size. We calculate the first order interaction correction to the free energy, as an upper ... More
Batalin-Vilkovisky algebra structures on (Co)Tor and Poisson bialgebroidsMay 14 2013Dec 28 2014In this article, we extend our preceding studies on higher algebraic structures of (co)homology theories defined by a left bialgebroid (U,A). For a braided commutative Yetter-Drinfel'd algebra N, explicit expressions for the canonical Gerstenhaber algebra ... More
Algorithms for singularities and real structures of weak Del Pezzo surfacesFeb 27 2013Jan 01 2014In this paper we consider the classification of singularities (Du Val) and real structures (Wall) of weak Del Pezzo surfaces from an algorithmic point of view. It is well known that the singularities of weak Del Pezzo surfaces correspond to root subsystems. ... More
Homogeneous Buchberger algorithms and Sullivant's computational commutative algebra challengeAug 16 2005We give a variant of the homogeneous Buchberger algorithm for positively graded lattice ideals. Using this algorithm we solve the Sullivant computational commutative algebra challenge.
Deriving the Gross-Pitaevskii equationApr 17 2014In experiments, Bose-Einstein condensates are prepared by cooling a dilute Bose gas in a trap. After the phase transition has been reached, the trap is switched off and the evolution of the condensate observed. The evolution is macroscopically described ... More
Quantum Corrections to the Schwarzschild and Kerr MetricsNov 08 2002We examine the corrections to the lowest order gravitational interactions of massive particles arising from gravitational radiative corrections. We show how the masslessness of the graviton and the gravitational self interactions imply the presence of ... More
A fields only version of the Lorentz Force Law: Particles replaced by their fieldsNov 20 2012We show that the Lorentz force law, F^L_1=q_1(E+v_1xB) being the charge on particle 1 interacting with the electromagnetic fields due to all other particles, can be written in a pure field form F^L_1=-\nabla_1 U^{EM}. In this expression U^{EM} is the ... More
Translationally invariant treatment of pair correlations in nuclei: I. Spin and isospin dependent correlationsJul 15 1996We study the extension of our translationally invariant treatment of few-body nuclear systems to heavier nuclei. At the same time we also introduce state-dependent correlation operators. Our techniques are tailored to those nuclei that can be dealt with ... More
Finding flows in the one-way measurement modelNov 29 2006Feb 29 2008The one-way measurement model is a framework for universal quantum computation, in which algorithms are partially described by a graph G of entanglement relations on a collection of qubits. A sufficient condition for an algorithm to perform a unitary ... More
A complete algorithm to find flows in the one-way measurement modelMar 08 2006Feb 16 2007This article is the complement to [quant-ph/0611284], which proves that flows (as introduced by [quant-ph/0506062]) can be found efficiently for patterns in the one-way measurement model which have non-empty input and output subsystems of the same size. ... More
Dimensional asymptotics of effective actions on S^n, and proof of Bär-Schopka's conjectureSep 01 2007We study the dimensional asymptotics of the effective actions, or functional determinants, for the Dirac operator D and Laplacians \Delta +\beta R on round S^n. For Laplacians the behavior depends on ``the coupling strength'' \beta, and one cannot in ... More
Note sur la détermination algébrique du groupe fondamental pro-résoluble d'une courbe affineAug 01 2007May 07 2008Let X be a smooth projective algebraic curve of genus g minus $r\geq 1$ points defined over an algebraically closed field k of characteristic $p\geq 0$. The structure of the largest prime to p quotient of the \'etale fundamental group is well known by ... More
Black Holes in Higher-Dimensional GravityFeb 04 2008These lectures review some of the recent progress in uncovering the phase structure of black hole solutions in higher-dimensional vacuum Einstein gravity. The two classes on which we focus are Kaluza-Klein black holes, i.e. static solutions with an event ... More
Cyclic structures in algebraic (co)homology theoriesNov 15 2010This note discusses the cyclic cohomology of a left Hopf algebroid ($\times_A$-Hopf algebra) with coefficients in a right module-left comodule, defined using a straightforward generalisation of the original operators given by Connes and Moscovici for ... More
Air-clad fibers: pump absorption assisted by chaotic wave dynamics?Jul 09 2007Wave chaos is a concept which has already proved its practical usefulness in design of double-clad fibers for cladding-pumped fiber lasers and fiber amplifiers. In general, classically chaotic geometries will favor strong pump absorption and we address ... More
Semi-analytical approach to short-wavelength dispersion and modal properties of photonic crystal fibersJan 17 2005Feb 14 2005We consider photonic crystal fibers made from arbitrary base materials and derive a unified semi-analytical approach for the dispersion and modal properties which applies to the short-wavelength regime. In particular we calculate the dispersion and the ... More
Nonparametric likelihood based estimation of linear filters for point processesApr 01 2013Feb 12 2014We consider models for multivariate point processes where the intensity is given nonparametrically in terms of functions in a reproducing kernel Hilbert space. The likelihood function involves a time integral and is consequently not given in terms of ... More
Sub-Poissonian Phonon Lasing in Three-Mode OptomechanicsFeb 13 2015We propose to use the resonant enhancement of the parametric instability in an optomechanical system of two optical modes coupled to a mechanical oscillator to prepare mechanical states with sub-Poissonian phonon statistics. Strong single photon coupling ... More
Klein's double discontinuity revisited: what use is university mathematics to high school calculus?Jun 29 2013Mar 10 2014Much effort and research has been invested into understanding and bridging the gaps which many students experience in terms of contents and expectations as they begin university studies with a heavy component of mathematics, typically in the form of calculus ... More
Entanglement-assisted atomic clock beyond the projection noise limitDec 19 2009Mar 21 2010We use a quantum non-demolition measurement to generate a spin squeezed state and to create entanglement in a cloud of 10^5 cold cesium atoms, and for the first time operate an atomic clock improved by spin squeezing beyond the projection noise limit ... More
Kinks in the Presence of Rapidly Varying PerturbationsMar 30 1994Dynamics of sine-Gordon kinks in the presence of rapidly varying periodic perturbations of different physical origins is described analytically and numerically. The analytical approach is based on asymptotic expansions, and it allows to derive, in a rigorous ... More
Chemoselective Reactivity of Bifunctional Cyclooctynes on Si(001)Sep 02 2016Controlled organic functionalization of silicon surfaces as integral part of semiconductor technology offers new perspectives for a wide range of applications. The high reactivity of the silicon dangling bonds, however, presents a major hindrance for ... More
BiographyNet: Extracting Relations Between People and EventsJan 22 2018This paper describes BiographyNet, a digital humanities project (2012-2016) that brings together researchers from history, computational linguistics and computer science. The project uses data from the Biography Portal of the Netherlands (BPN), which ... More
The Hidden K-edge Signal in K-edge ImagingJun 13 2015K-edge imaging is commonly used for viewing contrast pharmaceuticals in a variety of multi-energy x-ray imaging techniques, ranging from dual-energy and spectral computed tomography to fluoroscopy. When looking for the K-edge signal of a specific contrast, ... More
Resonant control of stochastic spatio-temporal dynamics in a tunnel diode by multiple time delayed feedbackSep 09 2008We study the control of noise-induced spatio-temporal current density patterns in a semiconductor nanostructure (double barrier resonant tunnelling diode) by multiple time-delayed feedback. We find much more pronounced resonant features of noise-induced ... More
Applying the effective-source approach to frequency-domain self-force calculations: Lorenz-gauge gravitational perturbationsMay 28 2015Jun 17 2015With a view to developing a formalism that will be applicable at second perturbative order, we devise a new practical scheme for computing the gravitational self-force experienced by a point mass moving in a curved background spacetime. Our method works ... More
Applying the effective-source approach to frequency-domain self-force calculationsNov 13 2013Oct 26 2014The equations of motion of a point particle interacting with its own field are defined in terms of a certain regularized self-field. Two of the leading methods for computing this regularized field are the mode-sum and effective-source approaches. In this ... More
The kinetic energy and and the geometric structure in the $B=2$ sector of the Skyrme model: A study using the Atiyah-Manton AnsatzOct 10 1994We study the construction of the collective-coordinate manifold in the baryon number two sector of the Skyrme model. To that end we use techniques of adiabatic large amplitude collective motion, which treat potential and kinetic energy on an equal footing. ... More
Comment on "Design of a broadband highly dispersive pure silica photonic crystal fiber" by Subbaraman et alJan 08 2008In a recent paper, Subbaraman et al report a theoretical and numerical study of highly dispersive pure silica photonic crystal fiber supporting group-velocity dispersion exceeding -2*10^4 ps/nm/km. This comment argues that the authors only consider one ... More
Mesoscopic Coulomb DragNov 21 2001This thesis describes the merging of the two fields of Coulomb drag and mesoscopic physics. The thesis presents a theory for Coulomb drag between two mesoscopic systems based on linear-response theory. The formalism expresses the drag in terms of either ... More
The maximum of a random walk reflected at a general barrierMar 09 2006We define the reflection of a random walk at a general barrier and derive, in case the increments are light tailed and have negative mean, a necessary and sufficient criterion for the global maximum of the reflected process to be finite a.s. If it is ... More
Self force on a scalar charge in Kerr spacetime: circular equatorial orbitsMar 09 2010Jun 29 2015We present a calculation of the scalar field self-force (SSF) acting on a scalar-charge particle in a strong-field orbit around a Kerr black hole. Our calculation specializes to circular and equatorial geodesic orbits. The analysis is an implementation ... More
Ray and wave scattering in smoothly curved thin shell cylindrical ridgesAug 16 2016We propose wave and ray approaches for modelling mid- and high- frequency structural vibrations through smoothed joints on thin shell cylindrical ridges. The models both emerge from a simplified classical shell theory setting. The ray model is analysed ... More
On restricted unitary Cayley graphs and symplectic transformations modulo nFeb 03 2010Jun 11 2010We present some observations on a restricted variant of unitary Cayley graphs modulo n, and the implications for a decomposition of elements of symplectic operators over the integers modulo n. We define quadratic unitary Cayley graphs G_n, whose vertex ... More