Results for "Thomas Willum Hansen"

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A deep learning approach to identify local structures in atomic-resolution transmission electron microscopy imagesFeb 08 2018Recording atomic-resolution transmission electron microscopy (TEM) images is becoming increasingly routine. A new bottleneck is then analyzing this information, which often involves time-consuming manual structural identification. We have developed a ... More
Cluster evolution in steady-state two-phase flow in porous mediaNov 24 2005Jan 05 2006We report numerical studies of the cluster development of two-phase flow in a steady-state environment of porous media. This is done by including biperiodic boundary conditions in a two-dimensional flow simulator. Initial transients of wetting and non-wetting ... More
The complexity of interior point methods for solving discounted turn-based stochastic gamesApr 06 2013Dec 17 2014We study the problem of solving discounted, two player, turn based, stochastic games (2TBSGs). Jurdzinski and Savani showed that 2TBSGs with deterministic transitions can be reduced to solving $P$-matrix linear complementarity problems (LCPs). We show ... More
Random-Facet and Random-Bland require subexponential time even for shortest pathsOct 28 2014The Random-Facet algorithm of Kalai and of Matousek, Sharir and Welzl is an elegant randomized algorithm for solving linear programs and more general LP-type problems. Its expected subexponential time of $2^{\tilde{O}(\sqrt{m})}$, where $m$ is the number ... More
Systematic Power Counting in Cutoff Effective Field Theories for Nucleon-Nucleon Interactions and the Equivalence With PDSAug 03 1998Aug 11 1998An analytic expression for the ${}^1S_0$ phase shifts in nucleon-nucleon scattering is derived in the context of the Schr\"odinger equation in configuration space with a short distance cutoff and with a consistent power counting scheme including pionic ... More
Strategy iteration is strongly polynomial for 2-player turn-based stochastic games with a constant discount factorAug 03 2010Ye showed recently that the simplex method with Dantzig pivoting rule, as well as Howard's policy iteration algorithm, solve discounted Markov decision processes (MDPs), with a constant discount factor, in strongly polynomial time. More precisely, Ye ... More
Self-Affinity in the Gradient Percolation ProblemNov 22 2005Jul 19 2006We study the scaling properties of the solid-on-solid front of the infinite cluster in two-dimensional gradient percolation. We show that such an object is self affine with a Hurst exponent equal to 2/3 up to a cutoff-length proportional to the gradient ... More
Simplistic Coulomb forces in molecular dynamics: Comparing the Wolf and shifted-force approximationsAug 26 2011This paper compares the Wolf method to the shifted forces (SF) method for efficient computer simulation of isotropic systems interacting via Coulomb forces, taking results from the Ewald summation method as representing the true behavior. We find that ... More
Magnetoelastic effects in multiferroic HoMnO$_3$Dec 18 2012We have investigated magnetoelastic effects in multiferroic HoMnO$_3$ below the antiferromagnetic phase transition $T_N \approx 75$ K by neutron powder diffraction. The lattice parameter $a$ of the hexagonal unit cell of HoMnO$_3$ decrease in the usual ... More
Kinetic Simulation of Filament Growth Dynamics in Memristive Electrochemical Metallization DevicesSep 01 2015Oct 31 2015In this work we report on kinetic Monte-Carlo calculations of resistive switching and the underlying growth dynamics of filaments in an electrochemical metallization device consisting of an Ag/TiO2/Pt sandwich-like thin film system. The developed model ... More
Ice XII in its second regime of metastabilityFeb 15 2000We present neutron powder diffraction results which give unambiguous evidence for the formation of the recently identified new crystalline ice phase[Lobban et al.,Nature, 391, 268, (1998)], labeled ice XII, at completely different conditions. Ice XII ... More
Cooee bitumen II: Stability of linear asphaltene nanoaggregatesJun 30 2014Sep 04 2014Asphaltene and smaller aromatic molecules tend to form linear nanoaggregates in bitumen.Over the years bitumen undergoes chemical aging and during this process, the size of the nanoaggregate increases. This increase is associated with an increase in viscosity ... More
Suppression of Antiferroelectric State in NaNbO3 at High Pressure from In Situ Neutron DiffractionOct 16 2012We report direct experimental evidence of antiferroelectric to paraelectric phase transition under pressure in NaNbO3 using neutron diffraction at room temperature. The paraelectric phase is found to stabilize above 8 GPa and its crystal structure has ... More
Universal coefficients for overconvergent cohomology and the geometry of eigenvarietiesSep 04 2012Oct 01 2012We prove a universal coefficients theorem for the overconvergent cohomology modules introduced by Ash and Stevens, and give several applications. In particular, we sketch a very simple construction of eigenvarieties using overconvergent cohomology and ... More
The Petersson norm of the Jacobi theta functionOct 03 2011We compute the Petersson norm of the Jacobi theta function, by a simple application of the Rankin-Selberg method and a little trick.
Intrinsic Hölder continuity of harmonic functionsOct 20 2015Nov 09 2016In a setting, where only exit measures are given, as they are associated with a right continuous strong Markov process on a separable metric space, we provide simple criteria for scaling invariant H\"older continuity of bounded harmonic functions with ... More
Jensen's inequality for conditional expectationsSep 22 2006We study conditional expectations generated by an abelian $ C^* $-subalgebra in the centralizer of a positive functional. We formulate and prove Jensen's inequality for functions of several variables with respect to this type of conditional expectations, ... More
The fast track to Löwner's theoremDec 01 2011Feb 03 2013The operator monotone functions defined in the positive half-line are of particular importance. We give a version of the theory in which integral representations for these functions can be established directly without invoking L\"owner's detailed analysis ... More
Monotone trace functions of several variablesJun 19 2006We investigate monotone operator functions of several variables under a trace or a trace-like functional. In particular, we prove the inequality \tau(x_1... x_n)\le\tau(y_1... y_n) for a trace \tau on a C^*-algebra and abelian n-tuples (x_1,...,x_n)\le ... More
Low-Cost Data Acquisition Card for School-Network Cosmic Ray DetectorsNov 14 2003The Cosmic Ray Observatory Project (CROP) at University of Nebraska/Lincoln and the Washington Area Large-scale Time coincidence Array (WALTA) at University of Washington/Seattle are among several outreach projects siting cosmic-ray detectors at local ... More
Large-Scale User Modeling with Recurrent Neural Networks for Music Discovery on Multiple Time ScalesAug 22 2017The amount of content on online music streaming platforms is immense, and most users only access a tiny fraction of this content. Recommender systems are the application of choice to open up the collection to these users. Collaborative filtering has the ... More
Applications of integrand reduction to two-loop five-point scattering amplitudes in QCDJul 25 2018Sep 25 2018We review the current state-of-the-art in integrand level reduction for five-point scattering amplitudes at two loops in QCD. We present some benchmark results for the evaluation of the leading colour two-loop five-gluon amplitudes in the physical region ... More
Characterization of a scintillating lithium glass ultra-cold neutron detectorAug 08 2016Nov 08 2016A $^{6}$Li glass based scintillation detector developed for the TRIUMF neutron electric dipole moment experiment was characterized using the ultra-cold neutron source at the Paul Scherrer Institute (PSI). The data acquisition system for this detector ... More
Subsonic Free Surface Waves in Linear ElasticityFeb 20 2013May 09 2014For general anisotropic linear elastic solids with smooth boundaries, Rayleigh-type surface waves are studied. Using spectral factorizations of matrix polynomials, a self-contained exposition of the case of a homogeneous half-space is given first. The ... More
How Can We Avert Dangerous Climate Change?Jun 25 2007Recent analyses indicate that the amount of atmospheric CO2 required to cause dangerous climate change is at most 450 ppm, and likely less than that. Reductions of non-CO2 climate forcings can provide only moderate, albeit important, adjustments to the ... More
Unavoidable collections of balls for processes with isotropic unimodal Green functionMar 01 2014Mar 19 2014Let us suppose that we have a right continuous Markov semigroup on $R^d$, $d\ge 1$, such that its potential kernel is given by convolution with a function $G_0=g(|\cdot|)$, where $g$ is decreasing, has a mild lower decay property at zero, and a very weak ... More
Darning and gluing of diffusionsJan 26 2016Mar 06 2016We introduce darning of compact sets (darning and gluing of finite unions of compact sets), which are not thin at any of their points, in a potential-theoretic framework which may be described, analytically, in terms of harmonic kernels/harmonic functions ... More
Hölder continuity of harmonic functions for Hunt processes with Green functionFeb 23 2015Let $(X,\mathcal W)$ be a balayage space, $1\in \mathcal W$, or - equivalently - let $\mathcal W$ be the set of excessive functions of a Hunt process on a locally compact space $X$ with countable base such that $\mathcal W$ separates points, every function ... More
Liouville property, Wiener's test and unavoidable sets for Hunt processesSep 26 2014Jan 27 2015Let $(X,\mathcal W)$ be a balayage space, $1\in \mathcal W$, or - equivalently - let $\mathcal W$ be the set of excessive functions of a Hunt process on a locally compact space $X$ with countable base such that $\mathcal W$ separates points, every function ... More
Do the repulsive and attractive pair forces play separate roles for the physics of liquids?Jul 06 2012Nov 28 2012According to standard liquid-state theory repulsive and attractive pair forces play distinct roles for the physics of liquids. This paradigm is put into perspective here by demonstrating a continuous series of pair potentials that have virtually the same ... More
Helical order and multiferroicity in the $S=1/2$ quasi-kagome system KCu$_3$As$_2$O$_7$(OD)$_3$Apr 11 2014Several Cu$^{2+}$ hydroxide minerals have recently been identified as candidate realizations of the $S=1/2$ kagome Heisenberg model. In this context, we have studied the distorted system KCu$_3$As$_2$O$_7$(OD)$_3$ using neutron scattering and bulk measurements. ... More
Origin of anomalous breakdown of Bloch's rule in the Mott-Hubbard insulator MnTe$_2$Feb 27 2015We reinvestigate the pressure dependence of the crystal structure and antiferromagnetic phase transition in MnTe$_2$ by the rigorous and reliable tool of high pressure neutron powder diffraction. First-principles density functional theory calculations ... More
Multi-site exchange enhanced barocaloric response in Mn$_{3}$NiNJun 06 2018Jun 08 2018We have studied the barocaloric effect (BCE) in the geometrically frustrated antiferromagnet Mn$_{3}$NiN across the N\'{e}el transition temperature. Experimentally we find a larger barocaloric entropy change by a factor of 1.6 than that recently discovered ... More
Computing FO-Rewritings in EL in Practice: from Atomic to Conjunctive QueriesApr 18 2018A prominent approach to implementing ontology-mediated queries (OMQs) is to rewrite into a first-order query, which is then executed using a conventional SQL database system. We consider the case where the ontology is formulated in the description logic ... More
A full space-time convergence order analysis of operator splittings for linear dissipative evolution equationsDec 18 2015The Douglas--Rachford and Peaceman--Rachford splitting methods are common choices for temporal discretizations of evolution equations. In this paper we combine these methods with spatial discretizations fulfilling some easily verifiable criteria. In the ... More
Quantum Codes from Toric SurfacesMar 20 2012A theory for constructing quantum error correcting codes from Toric surfaces by the Calderbank-Shor-Steane method is presented. In particular we study the method on toric Hirzebruch surfaces. The results are obtained by constructing a dualizing differential ... More
Toric Codes, Multiplicative Structure and DecodingFeb 20 2017Long linear codes constructed from toric varieties over finite fields, their multiplicative structure and decoding. The main theme is the inherent multiplicative structure on toric codes. The multiplicative structure allows for \emph{decoding}, resembling ... More
On the potentially dramatic history of the super-Earth rho 55 Cancri eMay 20 2015We demonstrate that tidal evolution of the inner planet (`e') of the system orbiting the star rho 55 Cancri could have led to passage through two secular resonances with other planets in the system. The consequence of this evolution is excitation of both ... More
Reduced functions and Jensen measuresNov 05 2016Feb 08 2017Let $\varphi$ be a locally upper bounded Borel measurable function on a Greenian open set $\Omega$ in $R^d$ and, for every $x\in \Omega$, let $v_\varphi(x)$ denote the infimum of the integrals of $\varphi$ with respect to Jensen measures for $x$ on $\Omega$. ... More
Nearly hyperharmonic functions and Jensen measuresMay 15 2017Let $(X,\mathcal H)$ be a $\mathcal P$-harmonic space and assume for simplicity that constants are harmonic. Given a numerical function $\varphi$ on $X$ which is locally lower bounded, let \begin{equation*} J_\varphi(x):=\sup\{\int^\ast \varphi\,d\mu(x)\colon ... More
A q-Analogue of Kempf's vanishing theoremMay 03 2009We use deep properties of Kashiwara's crystal basis to show that the induction functor $ {H}^0 (-) $ introduced by Andersen, Polo and Wen satisfies an analogon of Kempf's vanishing Theorem.
Nonlinear Magnetohydrodynamics from GravityNov 21 2008Jan 08 2009We apply the recently established connection between nonlinear fluid dynamics and AdS gravity to the case of the dyonic black brane in AdS_4. This yields the equations of fluid dynamics for a 2+1 dimensional charged fluid in a background magnetic field. ... More
Osculating Spaces of Varieties and Linear Network CodesOct 30 2012May 14 2013We present a general theory to obtain good linear network codes utilizing the osculating nature of algebraic varieties. In particular, we obtain from the osculating spaces of Veronese varieties explicit families of equidimensional vector spaces, in which ... More
Sextet Model with Wilson FermionsOct 25 2016We present new results from our ongoing study of the SU(3) sextet model with two flavors in the two-index symmetric representation of the gauge group. In the simulations use unimproved Wilson fermions to investigate the infrared properties of the model. ... 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
Convergence analysis of domain decomposition based time integrators for degenerate parabolic equationsAug 04 2017Domain decomposition based time integrators allow the usage of parallel and distributed hardware, making them well-suited for the temporal discretization of parabolic systems, in general, and degenerate parabolic problems, in particular. The latter is ... More
The Measurement Problem Is the "Measurement" ProblemOct 10 2018Physics builds on two tenets: On the one hand, statements are expressed in formal languages. On the other, these statements are to be tested against experience. Observers are the nexus between experience and the account thereof. Whether this very account ... More
Nearly hyperharmonic functions are infima of excessive functionsSep 23 2018Nov 13 2018Let $\mathfrak X$ be a Hunt process on a locally compact space $X$ such that the set $\mathcal E_{\mathfrak X}$ of its Borel measurable excessive functions separates points, every function in $\mathcal E_{\mathfrak X}$ is the supremum of its continuous ... More
Capillary-Driven Instability of Immiscible Fluid Interfaces Flowing in Parallel in Porous MediaSep 20 2007Jun 04 2008When immiscible wetting and non-wetting fluids move in parallel in a porous medium, an instability may occur at sufficiently high capillary numbers so that interfaces between the fluids initially held in place by the porous medium are mobilized. A boundary ... More
First Class Constrained Systems and Twisting of Courant Algebroids by a Closed 4-formApr 04 2009We show that in analogy to the introduction of Poisson structures twisted by a closed 3-form by Park and Klimcik-Strobl, the study of three dimensional sigma models with Wess-Zumino term leads in a likewise way to twisting of Courant algebroid structures ... More
Propagation of Polarization in Elastodynamics with Residual Stress and Travel TimesJan 17 2002We show that knowing the Dirichlet-to-Neumann map (DN) associated to the equations of elastodynamics with residual stress we can determine the lens relations of presssure and shear waves. We derive several consequences of this for the inverse problem ... More
Accelerated expansion and the virial theoremMar 31 2012When dark matter structures form and equilibrate they have to release a significant amount of energy in order to obey the virial theorem. Since dark matter is believed to be unable to radiate, this implies that some of the accreted dark matter particles ... More
Description of the Damn Yankee Controller (DYC)Oct 14 2002Versions of the Damn Yankee Controller (DYC) have been used to read out digitizers on the Fermilab E791, E835, FOCUS, SELEX, and KTeV experiments. The DYC accepts 16-bit data and control signals from 10 MHz Emitter Coupled Logic (ECL) PORT digitizing ... More
Forms and Linear Network CodesMar 07 2013We present a general theory to obtain linear network codes utilizing forms and obtain explicit families of equidimensional vector spaces, in which any pair of distinct vector spaces intersect in the same small dimension. The theory is inspired by the ... More
Equidistant Linear Network Codes with maximal Error-protection from Veronese VarietiesJul 09 2012May 22 2013Linear network coding transmits information in terms of a basis of a vector space and the information is received as a basis of a possible altered vectorspace. Ralf Koetter and Frank R. Kschischang in Coding for errors and erasures in random network coding ... More
Generating Charge from DiffeomorphismsJun 23 2006Sep 18 2006We unravel some subtleties involving the definition of sphere angular momentum charges in AdS_q \times S^p spacetimes, or equivalently, R-symmetry charges in the dual boundary CFT. In the AdS_3 context, it is known that charges can be generated by coordinate ... More
An inequality for expectation of means of positive random variablesAug 30 2016Suppose that $X,Y$ are positive random variable and $m$ a numerical (commutative) mean. We prove that the inequality ${\rm E} (m(X,Y)) \leq m({\rm E} (X), {\rm E} (Y))$ holds if and only if the mean is generated by a concave function. With due changes ... More
A dynamical context for the origin of Phobos and DeimosJan 23 2018We show that a model in which Mars grows near Earth and Venus but is then scattered out of the terrestrial region yields a natural pathway to explain the low masses of the Martian moons Phobos & Deimos. In this scenario, the last giant impact experienced ... More
Riemann-Roch Spaces and Linear Network CodesMar 09 2015We construct linear network codes utilizing algebraic curves over finite fields and certain associated Riemann-Roch spaces and present methods to obtain their parameters. In particular we treat the Hermitian curve and the curves associated with the Suzuki ... More
Secret Sharing Schemes with a large number of players from Toric VarietiesOct 16 2014Mar 13 2016A general theory for constructing linear secret sharing schemes over a finite field $\Fq$ from toric varieties is introduced. The number of players can be as large as $(q-1)^r-1$ for $r\geq 1$. We present general methods for obtaining the reconstruction ... More
Disturbance: It's a Feature, not a BugFeb 06 2019Results of measurements give legitimacy to a physical theory: What if acquiring these results in the first place necessitates what the same theory considers to be an interaction? In this note, we assume that theories account for interactions so that they ... More
Hunt's hypothesis (H) and the triangle property of the Green functionNov 11 2014Let $X$ be a locally compact abelian group with countable base and let $\mathcal W$ be a convex cone of positive numerical functions on $X$ which is invariant under the group action and such that $(X,\mathcal W)$ is a balayage space or (equivalently, ... More
Asymmetric Quantum Codes on Toric SurfacesAug 09 2017Asymmetric quantum error-correcting codes are quantum codes defined over biased quantum channels: qubit-flip and phase-shift errors may have equal or different probabilities. The code construction is the Calderbank-Shor-Steane construction based on two ... More
Similarities between structural distortions under pressure and chemical doping in superconducting BaFe2As2Dec 11 2009The discovery of a new family of high Tc materials, the iron arsenides (FeAs), has led to a resurgence of interest in superconductivity. Several important traits of these materials are now apparent, for example, layers of iron tetrahedrally coordinated ... More
Jucys-Murphy operators for Soergel bimodulesJul 12 2016We produce Jucys-Murphy elements for the diagrammatical category of Soergel bimodules associated with general Coxeter groups, and use them to diagonalize the bilinear form on the cell modules. This gives rise to an expression for the determinant of the ... More
On the denominators of Young's seminormal basisApr 27 2009Feb 16 2010We study the seminormal basis ${f\_t}$ for the Specht modules of the Iwahori-Hecke algebra $\cal H\_{q,n}$ of type $A_{n-1}$. We focus on the base change coefficients between the seminormal basis ${f\_t}$ and Young's natural basis ${e\_t}$ with emphasis ... More
A Spectral Method for the Eigenvalue Problem for Elliptic EquationsSep 19 2009Let $\Omega$ be an open, simply connected, and bounded region in $\mathbb{R}^{d}$, $d\geq2$, and assume its boundary $\partial\Omega$ is smooth. Consider solving the eigenvalue problem $Lu=\lambda u$ for an elliptic partial differential operator $L$ over ... More
Linear Convergence of Comparison-based Step-size Adaptive Randomized Search via Stability of Markov ChainsOct 29 2013Jun 02 2016In this paper, we consider comparison-based adaptive stochastic algorithms for solving numerical optimisation problems. We consider a specific subclass of algorithms that we call comparison-based step-size adaptive randomized search (CB-SARS), where the ... More
S-duality in AdS/CFT magnetohydrodynamicsJul 16 2009We study the nonlinear hydrodynamics of a 2+1 dimensional charged conformal fluid subject to slowly varying external electric and magnetic fields. Following recent work on deriving nonlinear hydrodynamics from gravity, we demonstrate how long wavelength ... More
One-radius results for supermedian functions on $\Bbb R^d$, $d\le 2$Aug 10 2009A classical result states that every lower bounded superharmonic function on $\Bbb R^2$ is constant. In this paper the following (stronger) one-circle version is proven. If $f\colon \Bbb R^2\to (-\infty,\infty]$ is lower semicontinuous, $\liminf_{|x|\to\infty} ... More
Differential analysis of matrix convex functions IIMar 09 2007We continue the analysis in [3] of matrix convex functions of a fixed order defined in a real interval by differential methods as opposed to the characterization in terms of divided differences given by Kraus [5]. We amend and improve some points in the ... More
The Factor-Lasso and K-Step Bootstrap Approach for Inference in High-Dimensional Economic ApplicationsNov 28 2016Dec 06 2016We consider inference about coefficients on a small number of variables of interest in a linear panel data model with additive unobserved individual and time specific effects and a large number of additional time-varying confounding variables. We allow ... More
Line bundles on rigid varieties and Hodge symmetryAug 28 2017We prove several related results on the low-degree Hodge numbers of proper smooth rigid analytic varieties over non-archimedean fields. Our arguments rely on known structure theorems for the relevant Picard varieties, together with recent advances in ... More
Semipolar sets and intrinsic Hausdorff measureNov 24 2017Given a "Green function" $G$ on a locally compact space $X$ with countable base, a Borel set $A$ in $X$ is called $G$-semipolar, if there is no measure $\nu\ne 0$ supported by $A$ such that $G\nu:=\int G(\cdot,y)\,d\nu(y)$ is a continuous real function ... More
Scaling invariant Harnack inequalities in a general settingApr 06 2016Jul 13 2016In a setting, where only "exit measures" are given, as they are associated with an arbitrary right continuous strong Markov process on a separable metric space, we provide simple criteria for the validity of Harnack inequalities for positive harmonic ... More
Jensen measures in potential theoryJul 08 2010It is shown that, for open sets in classical potential theory and - more generally - for elliptic harmonic spaces, the set of Jensen measures for a point is a simple union of closed faces of a compact convex set which has been thoroughly studied a long ... More
Variational representations related to Tsallis relative entropyJan 21 2019We develop variational representations for the deformed logarithmic and exponential functions and use them to obtain variational representations related to the quantum Tsallis relative entropy. We extend Golden-Thompson's trace inequality to deformed ... More
Convexity of limits of harmonic measuresAug 10 2006It is shown that, given a point $x\in\mathbbm{R}^d$, $d\ge 2$, and open sets $U_1,...,U_k$ containing $x$, any convex combination of the harmonic measures for $x$ with respect to $U_n$, $1\le n\le k$, is the limit of a sequence of harmonic measures for ... More
A Convergence Analysis of the Peaceman--Rachford Scheme for Semilinear Evolution EquationsDec 18 2015The Peaceman--Rachford scheme is a commonly used splitting method for discretizing semilinear evolution equations, where the vector fields are given by the sum of one linear and one nonlinear dissipative operator. Typical examples of such equations are ... More
The Ariki-Terasoma-Yamada tensor space and the blob-algebraMay 12 2005Mar 11 2010We show that the Ariki-Terasoma-Yamada tensor module and its permutation submodules $ M(\lambda) $ are modules for the blob algebra when the Ariki-Koike algebra is a Hecke algebra of type $B$. We show that $ M(\lambda)$ and the standard modules $ \Delta(\lambda) ... More
Implications of Realistic Fracture Criteria on Crack MorphologyAug 19 2018We study the effects realistic fracture criteria have on crack morphology obtained in numerical simulations with a stochastic discrete element method. Results are obtained with two criteria which are consistent with the theory of elasticity and compared ... More
Harnack inequalities for Hunt processes with Green functionOct 12 2014Feb 09 2015Let $(X,\mathcal W)$ be a balayage space, $1\in \mathcal W$, or - equivalently - let $\mathcal W$ be the set of excessive functions of a Hunt process on a locally compact space $X$ with countable base such that $\mathcal W$ separates points, every function ... More
Champagne subregions with unavoidable bubblesJun 07 2012Jun 17 2012A champagne subregion of a connected open set $U\ne\emptyset$ in $R^d$, $d\ge 2$, is obtained omitting pairwise disjoint closed balls $\bar B(x, r_x)$, $x\in X$, the bubbles, where $X$ is a locally finite set in $U$. The union $A$ of these balls may be ... More
Champagne subdomains with unavoidable bubblesJul 31 2012A champagne subdomain of a connected open set $U\ne\emptyset$ in $R^d$, $d\ge 2$, is obtained omitting pairwise disjoint closed balls $\bar{B}(x,r_x)$, $x\in X$, the bubbles, where $X$ is an infinite, locally finite set in $U$. The union $A$ of these ... More
On quadratic curves over finite fieldsFeb 28 2018The geometry of algebraic curves over finite fields is a rich area of research. In previous work, the authors investigated a particular aspect of the geometry over finite fields of the classical unit circle, namely how the number of solutions of the circle ... More
Graded cellular basis and Jucys-Murphy elements for generalized blob algebrasDec 28 2018Jan 18 2019We give a concrete construction of a graded cellular basis for the generalized blob algebra B_n introduced by Martin and Woodcock. The construction uses the isomorphism between KLR-algebras and cyclotomic Hecke algebras, proved by Brundan-Kleshchev and ... More
On the absence of the RIP in real-world applications of compressed sensing and the RIP in levelsNov 17 2014Oct 16 2015The purpose of this paper is twofold. The first is to point out that the Restricted Isometry Property (RIP) does not hold in many applications where compressed sensing is successfully used. This includes fields like Magnetic Resonance Imaging (MRI), Computerized ... More
Paleoclimate Implications for Human-Made Climate ChangeMay 05 2011Jul 20 2011Paleoclimate data help us assess climate sensitivity and potential human-made climate effects. We conclude that Earth in the warmest interglacial periods of the past million years was less than 1{\deg}C warmer than in the Holocene. Polar warmth in these ... More
The transition from highly to fully stretched polymer brushes in good solventSep 21 2007The stretching of brushes of long polymers grafted to a planar surface is investigated byMonte Carlo simulations in the limit of very high grafting densities, as achieved in recent experiments. The monomer density profiles are shown to deviate considerably ... More
Structure and dielectric properties of polar fluids with extended dipoles: results from numerical simulationsNov 28 2003The strengths and short-comings of the point-dipole model for polar fluids of spherical molecules are illustrated by considering the physically more relevant case of extended dipoles formed by two opposite charges $\pm q$ separated by a distance $d$ (dipole ... More
Colloid aggregation induced by oppositely charged polyionsJan 02 2002The "polymer reference interaction site model" (PRISM) integral equation formalism is used to determine the pair structure of binary colloidal dispersions involving large and small polyions of opposite charge. Two examples of such bidisperse suspensions ... More
A Wigner-Seitz model of charged lamellar colloidal dispersionsMar 21 1997A concentrated suspension of lamellar colloidal particles (e. g. clay) is modelled by considering a single, uniformly charged, finite platelet confined with co- and counterions to a Wigner-Seitz (WS) cell. The system is treated within Poisson-Boltzmann ... More
Hybridization of sub-gap states in one-dimensional superconductor/semiconductor Coulomb islandsApr 25 2018We present measurements of one-dimensional superconductor-semiconductor Coulomb islands, fabricated by gate confinement of a two-dimensional InAs heterostructure with an epitaxial Al layer. When tuned via electrostatic side gates to regimes without sub-gap ... More
Magnetoelastic effects in Jahn-Teller distorted CrF$_2$ and CuF$_2$ studied by neutron powder diffractionJun 07 2011We have studied the temperature dependence of crystal and magnetic structures of the Jahn-Teller distorted transition metal difluorides CrF$_2$ and CuF$_2$ by neutron powder diffraction in the temperature range 2-280 K. The lattice parameters and the ... More
A hard-sphere model on generalized Bethe lattices: StaticsJan 24 2005May 10 2005We analyze the phase diagram of a model of hard spheres of chemical radius one, which is defined over a generalized Bethe lattice containing short loops. We find a liquid, two different crystalline, a glassy and an unusual crystalline glassy phase. Special ... More
A detailed statistical analysis of the mass profiles of galaxy clustersJul 06 2009May 06 2011The distribution of mass in the halos of galaxies and galaxy clusters has been probed observationally, theoretically, and in numerical simulations. Yet there is still confusion about which of several suggested parameterized models is the better representation, ... More
Reshetikhin-Turaev invariants of Seifert 3-manifolds for classical simple Lie algebras, and their asymptotic expansionsSep 30 2002Feb 02 2003We derive formulas for the Reshetikhin-Turaev invariants of all oriented Seifert manifolds associated to an arbitrary complex finite dimensional simple Lie algebra $\mathfrak g$ in terms of the Seifert invariants and standard data for $\mathfrak g$. A ... More
Zeldovich pancakes at redshift zero: the equilibration state and phase space propertiesNov 24 2014One of the components of the cosmic web are sheets, which are commonly referred to as Zeldovich pancakes. These are structures which have only collapsed along one dimension, as opposed to filaments or galaxies and cluster, which have collapsed along two ... More
Attraction between like-charged colloidal particles induced by a surface a density - functional analysisSep 14 1998We show that the first non-linear correction to the linearised Poisson-Boltzman n (or DLVO) theory of effective pair interactions between charge-stabilised, co lloidal particles near a charged wall leads to an attractive component of entro pic origin. ... More
A new random mapping modelMar 22 2006We introduce a new random mapping model, $T_n^{\hat D}$, which maps the set $\{1,2,...,n\}$ into itself.The random mapping $T_n^{\hat D}$ is constructed using a collection of exchangeable random variables $\hat{D}_1, ....,\hat{D}_n$ which satisfy $\sum_{i=1}^n\hat{D}_i=n$. ... More