Results for "Ronald Holzlöhner"

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Polarization-driven spin precession of mesospheric sodium atomsSep 11 2018We report experimental results on the first on-sky observation of atomic spin precession of mesospheric sodium driven by polarization modulation of a continuous-wave laser. The magnetic resonance was remotely detected from the ground by observing the ... More
Remote sensing of geomagnetic fields and atomic collisions in the mesosphereFeb 09 2018Magnetic-field sensing has contributed to the formulation of the plate-tectonics theory, the discovery and mapping of underground structures on Earth, and the study of magnetism in other planets. Filling the gap between space-based and near-Earth observation, ... More
Magnetometry with Mesospheric SodiumDec 22 2009Measurement of magnetic fields on the few-hundred-kilometer length scale is significant for a variety of geophysical applications including mapping of crustal magnetism and ocean-circulation measurements, yet available techniques for such measurements ... More
The blowup formula for Donaldson invariantsMay 09 1994Jul 07 1994In this paper we present a formula which relates the Donaldson invariants of a 4-manifold X with the Donaldson invariants of its blowup X#-CP(2). This blow-up formula is independent of X and involves sigma-functions associated to a naturally arising elliptic ... More
Rational Blowdowns of Smooth 4-ManifoldsMay 17 1995In this paper we introduce a surgical procedure, called a rational blowdown, for a smooth 4-manifold X and determine how this procedure affects both the Donaldson and Seiberg-Witten invariants of X.
Modelling and Computing Homotopy Types: IOct 24 2016The aim of this article is to explain a philosophy for applying higher dimensional Seifert-van Kampen Theorems, and how the use of groupoids and strict higher groupoids resolves some foundational anomalies in algebraic topology at the border between homology ... More
Rain, power laws, and advectionOct 15 2002Localized rain events have been found to follow power-law size and duration distributions over several decades, suggesting parallels between precipitation and seismic activity [O. Peters et al., PRL 88, 018701 (2002)]. Similar power laws are generated ... More
Comment: Fisher Lecture: Dimension Reduction in RegressionAug 28 2007Comment: Fisher Lecture: Dimension Reduction in Regression [arXiv:0708.3774]
Covering morphisms of groupoids, derived modules and a 1-dimensional Relative Hurewicz TheoremDec 13 2010Jan 08 2011We fill a lacuna in the literature by giving a version in dimension 1 of the Relative Hurewicz Theorem, and relate this to abelianisations of groupoids, covering spaces and covering morphisms of groupoids, and Crowell's notion of derived modules.
Three themes in the work of Charles Ehresmann: Local-to-global; Groupoids; Higher dimensionsFeb 22 2006Mar 04 2006This paper illustrates the themes of the title in terms of: van Kampen type theorems for the fundamental groupoid; holonomy and monodromy groupoids; and higher homotopy groupoids. Interaction with work of the writer is explored.
Crossed modules and the homotopy 2-type of a free loop spaceMar 29 2010May 23 2010The question was asked by Niranjan Ramachandran: how to describe the fundamental groupoid of LX, the free loop space of a space X? We give an answer by assuming X to be the classifying space of a crossed module over a group, and then describe completely ... More
Computing Homotopy Types Using Crossed N-Cubes of GroupsSep 14 2001Aug 13 2006The aim of this paper is to explain how, through the work of a number of people, some algebraic structures related to groupoids have yielded algebraic descriptions of homotopy n-types. Further, these descriptions are explicit, and in some cases completely ... More
Duality theory for Markov processes: Part 1Feb 11 2010This is the first part of a possible monograph on the duality of Markov processes. It contains a proof of Fitzsimmons' existence theorem of a moderate Markov dual process relative to an excessive measure, m, together with the necessary preliminary material. ... More
Possible connections between whiskered categories and groupoids, many object Leibniz algebras, automorphism structures and local-to-global questionsAug 13 2007Jul 28 2010We define the notion of whiskered categories and groupoids, showing that whiskered groupoids have a commutator theory. So also do whiskered $R$-categories, thus answering questions of what might be `commutative versions' of these theories. We relate these ... More
Upper Bounds on the Number of Vertices of Weight <=k in Particular Arrangements of PseudocirclesJun 06 2007Jun 13 2008In arrangements of pseudocircles (Jordan curves) the weight of a vertex (intersection point) is the number of pseudocircles that contain the vertex in its interior. We give improved upper bounds on the number of vertices of weight <=k in certain arrangements ... More
Resonant Interactions Along the Critical Line of the Riemann Zeta FunctionSep 18 2013Nov 11 2013We have studied some properties of the special Gram points of the Riemann zeta function which lie on contour lines ${\bf Im}(\zeta ( s )) = 0$ which do not contain zeroes of $\zeta ( s )$. We find that certain functions of these points, which all lie ... More
An Evolutionary Optimization Approach to Risk Parity Portfolio SelectionNov 27 2014Jan 19 2015In this paper we present an evolutionary optimization approach to solve the risk parity portfolio selection problem. While there exist convex optimization approaches to solve this problem when long-only portfolios are considered, the optimization problem ... More
Stochastic energetics of a Brownian motor and refrigerator driven by non-uniform temperatureJul 05 2009Jun 02 2014The energetics of a Brownian heat engine and heat pump driven by position dependent temperature, known as the B\"uttiker-Landauer heat engine and heat pump, is investigated by numerical simulations of the inertial Langevin equation. We identify parameter ... More
N-Site approximations and CAM analysis for a stochastic sandpileApr 29 2002I develop n-site cluster approximations for a stochastic sandpile in one dimension. A height restriction is imposed to limit the number of states: each site can harbor at most two particles (height z_i \leq 2). (This yields a considerable simplification ... More
Numerical Study of a Field Theory for Directed PercolationJul 12 1994A numerical method is devised for study of stochastic partial differential equations describing directed percolation, the contact process, and other models with a continuous transition to an absorbing state. Owing to the heightened sensitivity to fluctuationsattending ... More
Percentile rank scores are congruous indicators of relative performance, or aren't they?Aug 09 2011Percentile ranks and the I3 indicator were introduced by Bornmann, Leydesdorff, Mutz and Opthof. These two notions are based on the concept of percentiles (or quantiles) for discrete data. As several definitions for these notions exist we propose one ... More
Local behaviour of first passage probabilitiesJun 28 2010Suppose that S is an asymptotically stable random walk with norming sequence c_{n} and that T_{x} is the time that S first enters (x,\inf), where x\ge 0. The asymptotic behaviour of P(T_0=n) has been described in a recent paper of Vatutin and Wachtel, ... More
Groupoids, the Phragmen-Brouwer Property and the Jordan Curve TheoremJul 09 2006We publicise a proof of the Jordan Curve Theorem which relates it to the Phragmen-Brouwer Property, and whose proof uses the van Kampen theorem for the fundamental groupoid on a set of base points.
Beyond the Imry-Ma Length: Scaling Behavior in the 3D Random Field $XY$ ModelDec 13 2018We have performed studies of the 3D random field $XY$ model on $L \times L \times L$ simple cubic lattices with periodic boundary conditions, with a random field strength of $h_r$ = 1.875, for $L =$ 64, 96 and 128, using a parallelized Monte Carlo algorithm. ... More
Structure Relations in Special A_\infty-bialgebrasJun 22 2005Jun 22 2005We compute the structure relations in special A_\infty-bialgebras whose operations are limited to those defining the underlying A_\infty-(co)algebra substructure. Such bialgebras appear as the homology of certain loop spaces. Whereas structure relations ... More
Embeddability of Arrangements of Pseudocircles into the SphereAug 17 2005An arrangement of pseudocircles is a finite set of oriented closed Jordan curves each two of which cross each other in exactly two points. To describe the combinatorial structure of arrangements on closed orientable surfaces, in (Linhart, Ortner 2004) ... More
Crossed complexes and homotopy groupoids as non commutative tools for higher dimensional local-to-global problemsDec 19 2002Oct 10 2008We outline the main features of the definitions and applications of crossed complexes and cubical $\omega$-groupoids with connections. These give forms of higher homotopy groupoids, and new views of basic algebraic topology and the cohomology of groups, ... More
Invariants for Lagrangian toriApr 25 2003Jul 09 2004We define an simple invariant of an embedded nullhomologous Lagrangian torus and use this invariant to show that many symplectic 4-manifolds have infinitely many pairwise symplectically inequivalent nullhomologous Lagrangian tori. We further show that ... More
Nondiffeomorphic symplectic 4-manifolds with the same Seiberg-Witten invariantsNov 04 1998Nov 17 1999The goal of this paper is to demonstrate that, at least for nonsimply connected 4-manifolds, the Seiberg-Witten invariant alone does not determine diffeomorphism type within the same homeomorphism type.
Knots, Links, and 4-ManifoldsDec 18 1996Jan 10 1997In this paper we investigate the relationship between isotopy classes of knots and links in S^3 and the diffeomorphism types of homeomorphic smooth 4-manifolds. As a corollary of this initial investigation, we begin to uncover the surprisingly rich structure ... More
Six Lectures on Four 4-ManifoldsOct 23 2006Jan 03 2007Despite spectacular advances in defining invariants for simply connected smooth and symplectic 4-dimensional manifolds and the discovery of effective surgical techniques, we still have been unable to classify simply connected smooth manifolds up to diffeomorphism. ... More
Pinwheels and nullhomologous surgery on 4-manifolds with b^+ = 1Apr 18 2010Apr 13 2011We present a method for finding embedded nullhomologous tori in standard 4-manifolds which can be utilized to change their smooth structure. As an application, we show how to obtain infinite families of simply connected smooth 4-manifolds with b^+ = 1 ... More
Families of Simply Connected 4-Manifolds with the Same Seiberg-Witten InvariantsOct 14 2002This article presents the constructions of new infinite families of smooth 4-manifolds with the property that any two manifolds in the same family are homeomorphic and, from their construction, seem to be quite different, but cannot be distinguished by ... More
A note on evolutionary stochastic portfolio optimization and probabilistic constraintsJan 29 2010In this note, we extend an evolutionary stochastic portfolio optimization framework to include probabilistic constraints. Both the stochastic programming-based modeling environment as well as the evolutionary optimization environment are ideally suited ... More
Computing trading strategies based on financial sentiment data using evolutionary optimizationApr 12 2015In this paper we apply evolutionary optimization techniques to compute optimal rule-based trading strategies based on financial sentiment data. The sentiment data was extracted from the social media service StockTwits to accommodate the level of bullishness ... More
Combinations and Mixtures of Optimal Policies in Unichain Markov Decision Processes are OptimalAug 17 2005We show that combinations of optimal (stationary) policies in unichain Markov decision processes are optimal. That is, let M be a unichain Markov decision process with state space S, action space A and policies \pi_j^*: S -> A (1\leq j\leq n) with optimal ... More
Contact process with mobile disorderMay 03 2009I study the absorbing-state phase transition in the one-dimensional contact process with mobile disorder. In this model the dilution sites, though permanently inactive, diffuse freely, exchanging positions with the other sites, which host a basic contact ... More
Nonequilibrium Phase Transitions in Epidemics and SandpilesOct 01 2001Nonequilibrium phase transitions between an active and an absorbing state are found in models of populations, epidemics, autocatalysis, and chemical reactions on a surface. While absorbing-state phase transitions fall generically in the DP universality ... More
Reweighting in nonequilibrium simulationsFeb 22 1999A simple reweighting scheme is proposed for Monte Carlo simulations of interacting particle systems, permitting one to study various parameter values in a single study, and improving efficiency by an order of magnitude. Unlike earlier reweighting schemes, ... More
Are the Dirac particles of the Standard Model dynamically confined states in a higher-dimensional flat space?Apr 02 1999Some time ago Rubakov and Shaposhnikov (RS) suggested that elementary particles might be excitations trapped on a soliton in a flat higher dimensional space. They gave as an example phi-4 theory in five dimensions with a bosonic excitation on a domain ... More
The matrix element for radiative Bhabha scattering in the forward directionAug 23 1993We present an approximation to the matrix element for the process e+e- --> e+e-gamma, appropriate to the situation where one or both of the fermions are scattered over very small angles. The leading terms in the situation where all scattering angles are ... More
Exact sequences of fibrations of crossed complexes, homotopy classification of maps, and nonabelian extensions of groupsFeb 29 2008Jun 25 2008The classifying space of a crossed complex generalises the construction of Eilenberg-Mac Lane spaces. We show how the theory of fibrations of crossed complexes allows the analysis of homotopy classes of maps from a free crossed complex to such a classifying ... More
Optimal packing of polydisperse hard-sphere fluids IIApr 27 2000We consider the consequences of keeping the total surface fixed for a polydisperse system of $N$ hard spheres. In contrast with a similar model (J. Zhang {\it et al.}, J. Chem. Phys. {\bf 110}, 5318 (1999)), the Percus-Yevick and Mansoori equations of ... More
A topologically induced 2-in/2-out operation on loop cohomologyAug 29 2011May 16 2012We apply the Transfer Algorithm introduced in arXiv:1106.5090 to transfer an A_\infty-algebra structure that cannot be computed using the classical Basic Perturbation Lemma. We construct a space X whose (base pointed) loop cohomology H = H^*(\Omega X; ... More
A Short Note on Stationary Distributions of Unichain Markov Decision ProcessesApr 20 2006Dealing with unichain MDPs, we consider stationary distributions of policies that coincide in all but $n$ states. In these states each policy chooses one of two possible actions. We show that the stationary distributions of n+1 such policies uniquely ... More
`Double modules', double categories and groupoids, and a new homotopical double groupoidMar 15 2009Mar 21 2009We give a rather general construction of double categories and so, under further conditions, double groupoids, from a structure we call a `double module'. We also give a homotopical construction of a double groupoid from a triad consisting of a space, ... More
Evolutionary multi-stage financial scenario tree generationDec 08 2009Jan 18 2010Multi-stage financial decision optimization under uncertainty depends on a careful numerical approximation of the underlying stochastic process, which describes the future returns of the selected assets or asset categories. Various approaches towards ... More
On point processes in multitarget trackingMar 08 2016The finite-set statistics (FISST) approach to multitarget tracking was introduced in the mid-1990s. Its current extended form dates from 2001. In 2008, an "elementary" alternative to FISST was proposed, based on "finite point processes" rather than RFS's. ... More
Absorbing-state phase transitions: exact solutions of small systemsSep 24 2007I derive precise results for absorbing-state phase transitions using exact (numerically determined) quasistationary probability distributions for small systems. Analysis of the contact process on rings of 23 or fewer sites yields critical properties (control ... More
Fractal rain distributions and chaotic advectionNov 17 2003Localized rain events have been found to follow power-law distributions over several decades, suggesting parallels between precipitation and seismic activity [O. Peters et al., PRL 88, 018701 (2002)]. Similar power laws can be generated by treating raindrops ... More
Generic slow relaxation in a stochastic sandpileSep 25 2002Simulations of a stochastic fixed-energy sandpile in one and two dimensions reveal slow relaxation of the order parameter, even far from the critical point. The decay of the activity is best described by a stretched-exponential form. The persistence probability ... More
Numerical analysis of the master equationOct 26 2001Applied to the master equation, the usual numerical integration methods, such as Runge-Kutta, become inefficient when the rates associated with various transitions differ by several orders of magnitude. We introduce an integration scheme that remains ... More
Discontinuous phase transition in a dimer lattice gasMay 27 2012I study a dimer model on the square lattice with nearest-neighbor exclusion as the only interaction. Detailed simulations using tomographic entropic sampling show that as the chemical potential is varied, there is a strongly discontinuous phase transition, ... More
Restricted sandpile revisitedJan 18 2006I report large-scale Monte Carlo studies of a one-dimensional height-restricted stochastic sandpile using the quasistationary simulation method. Results for systems of up to 50 000 sites yield estimates for critical exponents that differ significantly ... More
Nonuniversal Critical Spreading in Two DimensionsOct 18 1995Continuous phase transitions are studied in a two dimensional nonequilibrium model with an infinite number of absorbing configurations. Spreading from a localized source is characterized by nonuniversal critical exponents, which vary continuously with ... More
Modelling and Computing Homotopy Types: IOct 24 2016Nov 01 2016The aim of this article is to explain a philosophy for applying higher dimensional Seifert-van Kampen Theorems, and how the use of groupoids and strict higher groupoids resolves some foundational anomalies in algebraic topology at the border between homology ... More
The Deformation Complex For DG Hopf AlgebrasJun 29 2001Sep 11 2002Let H be a differential graded Hopf algebra over a field k. This paper gives an explicit construction of a triple cochain complex that defines the Hochschild-Cartier cohomology of H. A certain truncation of this complex is the appropriate setting for ... More
Tori in symplectic 4-manifoldsNov 19 2003Sep 29 2004We study the question of how many embedded symplectic or Lagrangian tori can represent the same homology class in a simply connected symplectic 4-manifold.
Symplectic surfaces in a fixed homology classFeb 04 1999Oct 08 1999The purpose of this paper is to investigate the following problem: For a fixed 2-dimensional homology class K in a simply connected symplectic 4-manifold, up to smooth isotopy, how many connected smoothly embedded symplectic submanifolds represent K? ... More
Double node neighborhoods and families of simply connected 4-manifolds with b^+=1Dec 07 2004Jan 18 2005We introduce a new technique that is used to show that the complex projective plane blown up at 6, 7, or 8 points has infinitely many distinct smooth structures. None of these smooth structures admit smoothly embedded spheres with self-intersection -1, ... More
Muon Collider: Plans, Progress and ChallengesApr 16 2012We in the physics community expect the LHC to uncover new physics in the next few years. The character and energy scale of the new physics remain unclear, but it is likely that data from the LHC will need to be complemented by information from a lepton ... More
Failure of steady state thermodynamics in lattice gases under nonuniform driveJul 29 2014To be useful, steady state thermodynamics (SST) must be self-consistent and have predictive value. Although consistency of SST was recently verified for driven lattice gases under global weak exchange, I show here that it does not predict the coexisting ... More
Ising Meets Ornstein and Zernike, Debye and Huckel, Widom and Rowlinson, and OthersDec 06 2000The name Ising has come to stand not only for a specific model, but for an entire universality class - arguably the most important such class - in the theory of critical phenomena. I review several examples, both in and out of equilibrium, in which Ising ... More
Nonuniversality and critical point shift in systems with infinitely many absorbing configurationsSep 23 1999A detailed study of critical spreading in the one-dimensional pair contact process is performed using a recently devised reweighting method. The results confirm the validity of a generalized hyperscaling relation among the (nonuniversal) spreading exponents, ... More
Phase coexistence far from equilibriumFeb 10 2016Investigation of simple far-from-equilibrium systems exhibiting phase separation leads to the conclusion that phase coexistence is not well defined in this context. This is because the properties of the coexisting nonequilibrium systems depend on how ... More
First- and second-order phase transitions in a driven lattice gas with nearest-neighbor exclusionSep 21 2000Oct 31 2000A lattice gas with infinite repulsion between particles separated by $\leq 1$ lattice spacing, and nearest-neighbor hopping dynamics, is subject to a drive favoring movement along one axis of the square lattice. The equilibrium (zero drive) transition ... More
Geometry of Thin FilmsNov 23 2015Jan 12 2016We study ray optics in the context of double mirror systems, in the limit as the two mirrors approach one another (thin films). This leads to a novel set of differential equations on a mirror surface which have interesting structure as seen from the perspective ... More
A note on percolation in cocycle measuresAug 09 2006We describe infinite clusters which arise in nearest-neighbour percolation for so-called cocycle measures on the square lattice. These measures arise naturally in the study of random transformations. We show that infinite clusters have a very specific ... More
Nonabelian Algebraic TopologyJul 15 2004Jul 27 2004This talk gave a sketch of the contents and background to a book with the title `Nonabelian algebraic topology' being written under support of a Leverhulme Emeritus Fellowship (2002-2004) by the speaker and Rafael Sivera (Valencia). The aim is to give ... More
Towards non commutative algebraic topologyMay 12 2003This is a slightly edited version of the transparencies for a seminar at UCL, May 7, 2003. It is intended to give a quick view of background, ideas, and some calculations, in the applicatioon of some non commutative methods to algebraic topology.
Exact analytic expression for a subset of fourth virial coefficients of polydisperse hard sphere mixturesDec 07 1998We derive an exact, analytic expression for the fourth virial coefficient of a system of polydisperse spheres under the constraint that the smallest sphere has a radius smaller than a given function of the radii of the three remaining particles.
J. L. Doob: Foundations of stochastic processes and probabilistic potential theorySep 23 2009During the three decades from 1930 to 1960 J. L. Doob was, with the possible exception of Kolmogorov, the man most responsible for the transformation of the study of probability to a mathematical discipline. His accomplishments were recognized by both ... More
Spin goups of super metrics and a Theorem of RogersFeb 15 2016We derive the canonical forms of super Riemannian metrics and the local isometry groups of such metrics. For certain super metrics we also compute the simply connected covering groups of the local isometry groups and interpret these as local spin groups ... More
Double groupoids, matched pairs and then matched triplesApr 08 2011In this note we show that the known relation between double groupoids and matched pairs of groups may be extended, or seems to extend, to the triple case. The references give some other occurrences of double groupoids.
A new higher homotopy groupoid: the fundamental globular omega-groupoid of a filtered spaceFeb 22 2007We use the n-globe with its skeletal filtration to define the fundamental globular omega--groupoid of a filtered space; the proofs use an analogous fundamental cubical omega--groupoid due to the author and Philip Higgins. This method also relates the ... More
Surgery on nullhomologous tori and simply connected 4-manifolds with b^+=1Jan 01 2007For 5 <= k <= 8 we show that the infinite family of exotic smooth structures on CP^2# k(-CP^2) can be achieved by 1/n - surgeries on a single embedded nullhomologous torus in a manifold R_k which is homeomorphic to CP^2# k(-CP^2).
Nonsymplectic 4-Manifolds with One Basic ClassJul 27 1999It is the purpose of this paper to construct families of examples of nonsymplectic 4-manifolds which (up to sign) have just one Seiberg-Witten basic class.
Surfaces in 4-ManifoldsMay 29 1997In this paper we introduce a technique, called rim surgery, which can change a smooth embedding of an orientable surface of positive genus and nonnegative self-intersection in a smooth 4-manifold while leaving the topological embedding unchanged.
Surfaces in 4-manifolds: AddendumNov 29 2005In this note we fill a gap in the proof of the main theorem (Theorem 1.2) of our paper 'Surfaces in 4-manifolds', Math. Res. Letters 4 (1997), 907-914.
Constructions of Smooth 4-ManifoldsJul 27 1999We describe a collection of constructions which illustrate a panoply of ``exotic'' smooth 4-manifolds.
Surgery on Nullhomologous ToriNov 18 2011Nov 28 2011By studying the example of smooth structures on CP^2#3(-CP^2) we illustrate how surgery on a single embedded nullhomologous torus can be utilized to change the symplectic structure, the Seiberg-Witten invariant, and hence the smooth structure on a 4-manifold. ... More
Rational surfaces and symplectic 4-manifolds with one basic classFeb 19 2002May 26 2002We present constructions of simply connected symplectic 4-manifolds which have (up to sign) one basic class and which fill up the geographical region between the half-Noether and Noether lines.
Exotic group actions on simply connected smooth 4-manifoldsFeb 05 2009Sep 17 2009We produce infinite families of exotic actions of finite cyclic groups on simply connected smooth 4-manifolds with nontrivial Seiberg-Witten invariants.
Mathematical Software: Past, Present, and FutureApr 13 2000This paper provides some reflections on the field of mathematical software on the occasion of John Rice's 65th birthday. I describe some of the common themes of research in this field and recall some significant events in its evolution. Finally, I raise ... More
Data Mining Cultural Aspects of Social Media MarketingJan 22 2014Apr 16 2014For marketing to function in a globalized world it must respect a diverse set of local cultures. With marketing efforts extending to social media platforms, the crossing of cultural boundaries can happen in an instant. In this paper we examine how culture ... More
Attractive forces between anisotropic inclusions in the membrane of a vesicleFeb 04 1999Apr 30 1999The fluctuation-induced interaction between two rod-like, rigid inclusions in a fluid vesicle is studied by means of canonical ensemble Monte Carlo simulations. The vesicle membrane is represented by a triangulated network of hard spheres. Five rigidly ... More
Connections of the Corona Problem with Operator Theory and Complex GeometryDec 03 2012The corona problem was motivated by the question of the density of the open unit disk D in the maximal ideal space of the algebra, H1(D), of bounded holomorphic functions on D. In this note we study relationships of the problem with questions in operator ... More
Asymptotic behavior of the order parameter in a stochastic sandpileMar 10 2004We derive the first four terms in a series for the order paramater (the stationary activity density rho) in the supercritical regime of a one-dimensional stochastic sandpile; in the two-dimensional case the first three terms are reported. We reorganize ... More
Competing Sudakov Veto AlgorithmsMay 30 2016Jun 20 2016We present a way to analyze the distribution produced by a Monte Carlo algorithm. We perform these analyses on several versions of the Sudakov veto algorithm, adding a cutoff, a second variable and competition between emission channels. The analysis allows ... More
Watch This Space: Observing Merging White DwarfsNov 29 2010The Laser Interferometer Space Antenna (LISA) will open the low-frequency (0.1-100 mHz) part of the gravitational wave spectrum to direct observation. Of order 3600 galactic close binary white dwarfs will be individually resolvable in its all-sky spectrum, ... More
Forensic Identification: Database likelihood ratios and familial DNA searchingJan 20 2012Oct 21 2012Familial Searching is the process of searching in a DNA database for relatives of a certain individual. It is well known that in order to evaluate the genetic evidence in favour of a certain given form of relatedness between two individuals, one needs ... More
Contributions to the Theory of Thermostated Systems II: Least Dissipation of Helmholtz Free Energy in Nano-BiologyMar 11 2015Mar 12 2015In this paper, we develop further the theory of thermostated systems along the lines of our earlier paper. Two results are highlighted: 1) in the Markov limit of the contracted description, a least dissipation of Helmholtz free energy principle is established; ... More
Inertial effects in B{ü}ttiker-Landauer Motor and Refrigerator at the Overdamped LimitMar 28 2008We investigate the energetics of a Brownian motor driven by position dependent temperature, commonly known as the B{\"u}ttiker-Landauer motor. Overdamped models (M=0) predict that the motor can attain Carnot efficiency. However, the overdamped limit ($M\to ... More
Thermal Conductivity of MgO at High PressuresAug 19 1997The first non-empirical computation of lattice thermal conductivity has been performed for MgO using molecular dynamics (MD), a non-empirical ionic model (the Variationally Induced Breathing (VIB) model), and Green-Kubo theory. The computation is first-principles ... More
Coupling of thermal and mass diffusion in regular binary thermal lattice-gasesSep 26 2001We have constructed a regular binary thermal lattice-gas in which the thermal diffusion and mass diffusion are coupled and form two nonpropagating diffusive modes. The power spectrum is shown to be similar in structure as for the one in real fluids, in ... More
Morphing for faster computations in transformation opticsJul 07 2014Aug 01 2014We propose to use morphing algorithms to deduce some approximate wave pictures of scattering by cylindrical invisibility cloaks of various shapes deduced from the exact computation (e.g. using a finite element method) of scattering by cloaks of two given ... More
Probing the integrated Sachs-Wolfe effect using embedded lens modelsApr 14 2015The photometry profile of the integrated Sachs-Wolfe (ISW) effect recently obtained by the Planck consortium by stacking patches of Cosmic Microwave Background (CMB) sky maps around a large number of cosmic voids, contains a cold ring at about half the ... More
Distance-redshift from an optical metric that includes absorptionJul 29 2009We show that it is possible to equate the intensity reduction of a light wave caused by weak absorption with a geometrical reduction in intensity caused by a "transverse" conformal transformation of the spacetime metric in which the wave travels. We are ... More
Phase Diagram of the Lattice Restricted Primitive ModelJun 24 1999We present a comprehensive study of the lattice restricted primitive model, i.e., a lattice gas consisting of an equal number of positively and negatively charged particles interacting via on-site exclusion and a 1/r potential. On the cubic lattice, Monte ... More
Factorial characters of some classical Lie groupsJul 23 2016A definition is offered of the factorial characters of the general linear group, the symplectic group and the orthogonal group in an odd dimensional space. It is shown that these characters satisfy certain flagged Jacobi-Trudi identities. These identities ... More