Results for "Katja Gosar"

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Cesium bright matter-wave solitons and soliton trainsFeb 08 2019A setup for studying bright matter-wave solitons of a cesium Bose-Einstein condensate (BEC) is presented. Production of a single soliton is demonstrated and dependence of soliton atom number on the interatomic interaction is studied. Formation of soliton ... More
Entanglement entropy of a scalar field across a spherical boundary in the Einstein universeSep 27 2013A scalar field in the ground state, when partially hidden from observation by a spherical boundary, acquires entanglement entropy $S$ proportional to the area of the surface. This area law is well established in flat space, where it follows almost directly ... More
The CMS Silicon Strip Tracker - Overview and StatusOct 28 2006With an active silicon area of more than 200 squaremetres, the silicon strip tracker of the CMS experiment, one of the experiments currently under construction for the future Large Hadron Collider at CERN, will be by far the largest silicon tracker in ... More
Coarse types of tropical matroid polytopesDec 14 2010Dec 15 2010Describing the combinatorial structure of the tropical complex $C$ of a tropical matroid polytope, we obtain a formula for the coarse types of the maximal cells of $C$. Due to the connection between tropical complexes and resolutions of monomial ideals, ... More
Searches for Gauge Mediated SUSY Breaking at LEPMay 29 2002Searches for neutralinos and sleptons with arbitrary lifetimes, as predicted in the framework of the Gauge Mediated Supersymmetry Breaking (GMSB) model, have been performed by the four LEP collaborations. No evidence for these particles has been found ... More
AHCAL Energy ResolutionJun 18 2010The CALICE collaboration has constructed highly granular hadronic and electromagnetic calorimeter prototypes to evaluate technologies for the use in detector systems at a future Linear Collider. The hadron calorimeter uses 7608 small scintillator cells ... More
Random walks on weighted, oriented percolation clustersJun 05 2015Nov 30 2015We consider a weighted random walk on the backbone of an oriented percolation cluster. We determine necessary conditions on the weights for Brownian scaling limits under the annealed and the quenched law. This model is a random walk in dynamic random ... More
The geometry of almost Einstein $(2,3,5)$ distributionsJun 03 2016Jul 25 2016We analyze the classic problem of existence of Einstein metrics in a given conformal structure for the class of conformal structures induced via Nurowski's construction by (oriented) $(2,3,5)$ distributions. We characterize in two ways such conformal ... More
Continuous time random walk for open systems: Fluctuation theorems and counting statisticsFeb 06 2008Apr 08 2008We consider continuous time random walks (CTRW) for open systems that exchange energy and matter with multiple reservoirs. Each waiting time distribution (WTD) for times between steps is characterized by a positive parameter a, which is set to a=1 if ... More
Estimating Probabilities of Default for Low Default PortfoliosNov 28 2004Apr 04 2005For credit risk management purposes in general, and for allocation of regulatory capital by banks in particular (Basel II), numerical assessments of the credit-worthiness of borrowers are indispensable. These assessments are expressed in terms of probabilities ... More
Pulse Propagation in Chains with Nonlinear InteractionsAug 14 2003Pulse propagation in nonlinear arrays continues to be of interest because it provides a possible mechanism for energy transfer with little dispersion. Here we show that common measures of pulse dispersion might be misleading; in strongly anharmonic systems ... More
Comprehensive study of phase transitions in relaxational systems with field-dependent coefficientsSep 05 2003We present a comprehensive study of phase transitions in single-field systems that relax to a non-equilibrium global steady state. The mechanism we focus on is not the so-called Stratonovich drift combined with collective effects, but is instead similar ... More
Tropical and Ordinary Convexity CombinedJan 31 2008Mar 23 2010A polytrope is a tropical polytope which at the same time is convex in the ordinary sense. A $d$-dimensional polytrope turns out to be a tropical simplex, that is, it is the tropical convex hull of $d+1$ points. This statement is equivalent to the known ... More
The Geometry of Almost Einstein (2,3,5) DistributionsJun 03 2016Jan 19 2017We analyze the classic problem of existence of Einstein metrics in a given conformal structure for the class of conformal structures inducedf Nurowski's construction by (oriented) (2,3,5) distributions. We characterize in two ways such conformal structures ... More
Convergence to the Tracy-Widom distribution for longest paths in a directed random graphMar 25 2013Aug 23 2013We consider a directed graph on the 2-dimensional integer lattice, placing a directed edge from vertex $(i_1,i_2)$ to $(j_1,j_2)$, whenever $i_1 \le j_1$, $i_2 \le j_2$, with probability $p$, independently for each such pair of vertices. Let $L_{n,m}$ ... More
Pulse Velocity in a Granular ChainSep 02 2003We discuss the applicability of two very different analytic approaches to the study of pulse propagation in a chain of particles interacting via a Hertz potential, namely, a continuum model and a binary collision approximation. While both methods capture ... More
Phase-Induced (In)-Stability in Coupled Parametric OscillatorsAug 02 2000We report results on a model of two coupled oscillators that undergo periodic parametric modulations with a phase difference $\theta$. Being to a large extent analytically solvable, the model reveals a rich $\theta$ dependence of the regions of parametric ... More
Spatial Patterns Induced Purely by Dichotomous DisorderMar 18 2003We study conditions under which spatially extended systems with coupling a la Swift-Hohenberg exhibit spatial patterns induced purely by the presence of quenched dichotomous disorder. Complementing the theoretical results based on a generalized mean-field ... More
Intracellular delay limits cyclic changes in gene expressionFeb 07 2006Based on previously published experimental observations and mathematical models for Hes1, p53 and NF-kB gene expression, we improve these models through a distributed delay formulation of the time lag between transcription factor binding and mRNA production. ... More
On Nurowski's conformal structure associated to a generic rank two distribution in dimension fiveOct 11 2007For a generic distribution of rank two on a manifold $M$ of dimension five, we introduce the notion of a generalized contact form. To such a form we associate a generalized Reeb field and a partial connection. From these data, we explicitly constructed ... More
A Temporally Sensitive Submodularity Framework for Timeline SummarizationOct 18 2018Timeline summarization (TLS) creates an overview of long-running events via dated daily summaries for the most important dates. TLS differs from standard multi-document summarization (MDS) in the importance of date selection, interdependencies between ... More
Conformal Structures Associated to Generic Rank 2 Distributions on 5-Manifolds - Characterization and Killing-Field DecompositionAug 04 2009Nov 10 2009Given a maximally non-integrable 2-distribution ${\mathcal D}$ on a 5-manifold $M$, it was discovered by P. Nurowski that one can naturally associate a conformal structure $[g]_{\mathcal D}$ of signature (2,3) on $M$. We show that those conformal structures ... More
Pulse Dynamics in a Chain of Granules With FrictionJul 03 2003We study the dynamics of a pulse in a chain of granules with friction. We present theories for chains of cylindrical granules (Hertz potential with exponent $n=2$) and of granules with other geometries ($n>2$). Our results are supported via numerical ... More
A non-normal Fefferman-type construction of split-signature conformal structures admitting twistor spinorsSep 20 2011We treat a non-normal Fefferman-type construction based on an inclusion $\SL(n+1)\embed\Spin(n+1,n+1)$. The construction associates a split signature $(n,n)$-conformal spin structure to a projective structure of dimension $n$. For $n\geq 3$ the induced ... More
The twistor spinors of generic 2- and 3-distributionsApr 21 2010Generic distributions on 5- and 6-manifolds give rise to conformal structures that were discovered by P. Nurowski resp. R. Bryant. We describe both as Fefferman-type constructions and show that for orientable distributions one obtains conformal spin structures. ... More
Fast k-best Sentence CompressionOct 28 2015A popular approach to sentence compression is to formulate the task as a constrained optimization problem and solve it with integer linear programming (ILP) tools. Unfortunately, dependence on ILP may make the compressor prohibitively slow, and thus approximation ... More
The greedy walk on an inhomogeneous Poisson processNov 29 2016The greedy walk is a deterministic walk that always moves from its current position to the nearest not yet visited point. In this paper we consider the greedy walk on an inhomogeneous Poisson point process on the real line. Our primary interest is whether ... More
A three-sphere swimmer for flagellar synchronizationNov 26 2012Feb 21 2013In a recent letter (Friedrich et al., Phys. Rev. Lett. 109:138102, 2012), a minimal model swimmer was proposed that propels itself at low Reynolds numbers by a revolving motion of a pair of spheres. The motion of the two spheres can synchronize by virtue ... More
Subdiffusion-limited reactionsMay 17 2001We consider the coagulation dynamics A+A -> A and A+A <-> A and the annihilation dynamics A+A -> 0 for particles moving subdiffusively in one dimension. This scenario combines the "anomalous kinetics" and "anomalous diffusion" problems, each of which ... More
Trapping reactions with subdiffusive traps and particles characterized by different anomalous diffusion exponentsOct 21 2005Oct 23 2005A number of results for reactions involving subdiffusive species all with the same anomalous exponent gamma have recently appeared in the literature and can often be understood in terms of a subordination principle whereby time t in ordinary diffusion ... More
Simulation of Deformation and Flow in Fractured, Poroelastic MaterialsJun 18 2016Aug 12 2016We introduce a coupled system of PDEs for the modeling of the fluid-fluid and fluid-solid interaction in a poroelastic material with a single static fracture. The fluid flow in the fracture is modeled by a lower-dimensional Darcy equation, which interacts ... More
Trapping reactions with subdiffusive traps and particlesApr 18 2006Reaction dynamics involving subdiffusive species is an interesting topic with only few known results, especially when the motion of different species is characterized by different anomalous diffusion exponents. Here we study the reaction dynamics of a ... More
The subdiffusive target problem: Survival probabilitySep 19 2007Nov 13 2007The asymptotic survival probability of a spherical target in the presence of a single subdiffusive trap or surrounded by a sea of subdiffusive traps in a continuous Euclidean medium is calculated. In one and two dimensions the survival probability of ... More
Subdiffusion-limited single species reactionsNov 14 2001We consider the coagulation dynamics A+A -> A and the annihilation dynamics A+A -> 0 for particles moving subdiffusively in one dimension, both on a lattice and in a continuum. The analysis combines the "anomalous kinetics" and "anomalous diffusion" problems, ... More
Mapping the dynamics of complex multi-dimensional systems onto a discrete set of states conserving mean first passage times: a Projective Dynamics approachApr 16 2010We consider any dynamical system that starts from a given ensemble of configurations and evolves in time until the system reaches a certain fixed stopping criterion, with the mean first-passage time the quantity of interest. We present a general method, ... More
Properties of the reaction front in a reaction-subdiffusion processApr 19 2006We study the reaction front for the process $A+B\to C$ in which the reagents move subdiffusively. We propose a fractional reaction-subdiffusion equation in which both the motion and the reaction terms are affected by the subdiffusive character of the ... More
Comment on "Mean First Passage Time for Anomalous Diffusion"Jan 07 2004We correct a previously erroneous calculation [Phys. Rev. E 62, 6065 (2000)] of the mean first passage time of a subdiffusive process to reach either end of a finite interval in one dimension. The mean first passage time is in fact infinite.
Efficiency at maximum power for classical particle transportAug 09 2012Aug 14 2012We derive the explicit analytic expression for the efficiency at maximum power in a simple model of classical particle transport.
Exploration and Trapping of Mortal Random WalkersApr 28 2013Jun 18 2013Exploration and trapping properties of random walkers that may evanesce at any time as they walk have seen very little treatment in the literature, and yet a finite lifetime is a frequent occurrence, and its effects on a number of random walk properties ... More
Number of distinct sites visited by a subdiffusive random walkerNov 09 2007Mar 17 2008The asymptotic mean number of distinct sites visited by a subdiffusive continuous time random walker in two dimensions seems not to have been explicitly calculated anywhere in the literature. This number has been calculated for other dimensions for only ... More
Left lane road electrificationNov 01 2010Oct 29 2012We propose the left-side electrification of multilane motorways in suburban areas as a practical way of implementing on-road charging in order to reduce the weight and price of electrically-powered automobiles. These could then be supplied energy en-route, ... More
Coupling highly excited nuclei to the atomic shell in dense astrophysical plasmasApr 25 2014Jul 25 2014In dense astrophysical plasmas, neutron capture populates highly excited nuclear states close to the neutron threshold. The impact of additional low-energy nuclear excitations via coupling to the atomic shell on the ability of the so-formed compound nucleus ... More
A Conceptual Reasoning Approach to Textual EllipsisMay 15 1996We present a hybrid text understanding methodology for the resolution of textual ellipsis. It integrates conceptual criteria (based on the well-formedness and conceptual strength of role chains in a terminological knowledge base) and functional constraints ... More
A Deep Learning Approach for Joint Video Frame and Reward Prediction in Atari GamesNov 21 2016Reinforcement learning is concerned with learning to interact with environments that are initially unknown. State-of-the-art reinforcement learning approaches, such as DQN, are model-free and learn to act effectively across a wide range of environments ... More
New relations between $G_2$-geometries in dimensions 5 and 7Jan 15 2016Jan 19 2016There are two well-known parabolic split $G_2$-geometries in dimension five, $(2,3,5)$-distributions and $G_2$-contact structures. Here we link these two geometries with yet another $G_2$-related contact structure, which lives on a seven-manifold. We ... More
Reaction-subdiffusion and reaction-superdiffusion equations for evanescent particles performing continuous time random walksNov 16 2009Starting from a continuous time random walk (CTRW) model of particles that may evanesce as they walk, our goal is to arrive at macroscopic integro-differential equations for the probability density for a particle to be found at point r at time t given ... More
Order statistics for d-dimensional diffusion processesMay 17 2001We present results for the ordered sequence of first passage times of arrival of N random walkers at a boundary in Euclidean spaces of d dimensions.
Evanescent continuous time random walksSep 30 2013We study how an evanescence process affects the number of distinct sites visited by a continuous time random walker in one dimension. We distinguish two very different cases, namely, when evanescence can only occur concurrently with a jump, and when evanescence ... More
Synchronization of globally coupled two-state stochastic oscillators with a state dependent refractory periodJun 08 2012We present a model of identical coupled two-state stochastic units each of which in isolation is governed by a fixed refractory period. The nonlinear coupling between units directly affects the refractory period, which now depends on the global state ... More
Memory-induced anomalous dynamics: emergence of diffusion, subdiffusion, and superdiffusion from a single random walk modelMay 16 2010Jun 21 2010We present a random walk model that exhibits asymptotic subdiffusive, diffusive, and superdiffusive behavior in different parameter regimes. This appears to be the first instance of a single random walk model leading to all three forms of behavior by ... More
Flavour Tagging at CLICFeb 28 2012We present the performance of the LCFI flavour tagging package in a realistic CLIC environment. The application is demonstrated on the examples of the measurement of the cross section times branching ratio of light Higgs decays to b and c quarks at 3 ... More
The CMS Silicon Strip Tracker: System Tests and Test Beam ResultsDec 22 2003With a total area of 210 squaremeters and about 15000 single silicon modules the silicon strip tracker of the CMS experiment at the LHC will be the largest silicon strip detector ever built. While the performance of the individual mechanical and electronic ... More
Nonequilibrium patterns and shape fluctuations in reactive membranesNov 01 2005A simple kinetic model of a two-component deformable and reactive bilayer is presented. The two differently shaped components are interconverted by a nonequilibrium reaction, and a phenomenological coupling between local composition and curvature is proposed. ... More
Beyond unimodal regression: modelling multimodality with piecewise unimodal regression or deconvolution modelsJun 06 2016Shape constraints enable us to reflect prior knowledge in regression settings. A unimodality constraint, for example, can describe the frequent case of a first increasing and then decreasing intensity. Yet, data shapes often exhibit multiple modes. Therefore, ... More
Set-oriented numerical computation of rotation setsFeb 20 2017Feb 22 2017We establish a set-oriented algorithm for the numerical approximation of the rotation set of homeomorphisms of the two-torus homotopic to the identity. A theoretical background is given by the concept of {\epsilon}-rotation sets. These are obtained by ... More
Breathers and Thermal Relaxation in Fermi-Pasta-Ulam ArraysOct 15 2002Breather stability and longevity in thermally relaxing nonlinear arrays depend sensitively on their interactions with other excitations. We review the relaxation of breathers in Fermi-Pasta-Ulam arrays, with a specific focus on the different relaxation ... More
Nuclear wave function interference in single-molecule electron transportJan 09 2006It is demonstrated that non-equilibrium vibrational effects are enhanced in molecular devices for which the effective potential for vibrations is sensitive to the charge state of the device. We calculate the electron tunneling current through a molecule ... More
Vibration-assisted tunneling through competing molecular statesJun 21 2005We calculate the non-linear tunneling current through a molecule with two electron-accepting orbitals which interact with an intramolecular vibration. We investigate the interplay between Coulomb blockade and non-equilibrium vibration-assisted tunneling ... More
Top Mass Measurement at CLIC at 500 GeVFeb 15 2012We present a study of the capability of a 500 GeV e+e- collider based on CLIC technology for precision measurements of top quark properties. The analysis is based on full detector simulations of the CLIC_ILD detector concept using Geant4, including realistic ... More
Confinement induces conformational transition of semiflexible polymer rings to figure eight formApr 26 2010Employing Monte Carlo simulations of semiflexible polymer rings in weak spherical confinement a conformational transition to figure eight shaped, writhed configurations is discovered and quantified.
Buckling of stiff polymer rings in weak spherical confinementMar 22 2010Jun 24 2010Confinement is a versatile and well-established tool to study the properties of polymers either to understand biological processes or to develop new nano-biomaterials. We investigate the conformations of a semiflexible polymer ring in weak spherical confinement ... More
Arrival statistics and exploration properties of mortal walkersAug 10 2013We study some of the salient features of the arrival statistics and explo- ration properties of mortal random walkers, that is, walkers that may die as they move, or as they wait to move. Such evanescence or death events have profound consequences for ... More
Survival probability of an immobile target in a sea of evanescent diffusive or subdiffusive traps: a fractional equation approachOct 03 2012We calculate the survival probability of an immobile target surrounded by a sea of uncorrelated diffusive or subdiffusive evanescent traps, i.e., traps that disappear in the course of their motion. Our calculation is based on a fractional reaction-subdiffusion ... More
Long Memory in a Linear Stochastic Volterra Differential EquationSep 07 2010In this paper we consider a linear stochastic Volterra equation which has a stationary solution. We show that when the kernel of the fundamental solution is regularly varying at infinity with a log-convex tail integral, then the autocovariance function ... More
Energy Relaxation in Fermi-Pasta-Ulam ArraysSep 20 2001The dynamics of energy relaxation in thermalized one- and two-dimensional arrays with nonlinear interactions depend in detail on the interactions and, in some cases, on dimensionality. We describe and explain these differences for arrays of the Fermi-Pasta-Ulam ... More
Reaction Front in an A+B -> C Reaction-Subdiffusion ProcessJan 07 2004We study the reaction front for the process A+B -> C in which the reagents move subdiffusively. Our theoretical description is based on a fractional reaction-subdiffusion equation in which both the motion and the reaction terms are affected by the subdiffusive ... More
Partout: A Distributed Engine for Efficient RDF ProcessingDec 21 2012The increasing interest in Semantic Web technologies has led not only to a rapid growth of semantic data on the Web but also to an increasing number of backend applications with already more than a trillion triples in some cases. Confronted with such ... More
Generation of dynamic structures in nonequilibrium reactive bilayersNov 01 2005We present a nonequlibrium approach for the study of a flexible bilayer whose two components induce distinct curvatures. In turn, the two components are interconverted by an externally promoted reaction. Phase separation of the two species in the surface ... More
Managing Systematic Mortality Risk in Life Annuities: An Application of Longevity DerivativesAug 01 2015This paper assesses the hedge effectiveness of an index-based longevity swap and a longevity cap. Although swaps are a natural instrument for hedging longevity risk, derivatives with non-linear pay-offs, such as longevity caps, also provide downside protection. ... More
A Variational Approach to Nonlocal Exciton-Phonon CouplingSep 19 1996In this paper we apply variational energy band theory to a form of the Holstein Hamiltonian in which the influence of lattice vibrations (optical phonons) on both local site energies (local coupling) and transfers of electronic excitations between neighboring ... More
Velocity Distribution in a Viscous Granular GasApr 16 2004Apr 20 2004We investigate the velocity relaxation of a viscous one-dimensional granular gas, that is, one in which neither energy nor momentum is conserved in a collision. Of interest is the distribution of velocities in the gas as it cools, and the time dependence ... More
Dynamics of Two GranulesJun 18 2003We study the dynamics of two particles that interact only when in contact. In this sense, although not in every particular, the interactions mimic those in granular materials. The detailed solution of the dynamics allows an analysis of the backscattering ... More
Particle Showers in a Highly Granular Hadron CalorimeterApr 15 2010The CALICE collaboration has constructed highly granular electromagnetic and hadronic calorimeter prototypes to evaluate technologies for the use in detector systems at a future Linear Collider. The hadron calorimeter uses small scintillator cells individually ... More
On the relation between event-based and time-based current statisticsSep 23 2009Mar 01 2010Current statistics can be calculated in various ways. Event-based approaches use the statistics of the number of events occuring during a given time. Time-based approaches use the statistics of the time needed to reach a given number of events. By analyzing ... More
Experimental and causal view on information integration in autonomous agentsJun 14 2016Aug 26 2016The amount of digitally available but heterogeneous information about the world is remarkable, and new technologies such as self-driving cars, smart homes, or the internet of things may further increase it. In this paper we examine certain aspects of ... More
Momentum and energy propagation in tapered granular chainsJul 04 2013We study momentum and energy propagation in 1D tapered chains of spherical granules which interact according to a Hertz potential. In this work we apply the binary collision approximation, which is based on the assumption that transfer of energy along ... More
Memory Lens: How Much Memory Does an Agent Use?Nov 21 2016We propose a new method to study the internal memory used by reinforcement learning policies. We estimate the amount of relevant past information by estimating mutual information between behavior histories and the current action of an agent. We perform ... More
Meta Reinforcement Learning with Latent Variable Gaussian ProcessesMar 20 2018Jul 07 2018Learning from small data sets is critical in many practical applications where data collection is time consuming or expensive, e.g., robotics, animal experiments or drug design. Meta learning is one way to increase the data efficiency of learning algorithms ... More
Asymptotic Dynamics of Breathers in Fermi-Pasta-Ulam ChainsMay 15 2002We study the asymptotic dynamics of breathers in finite Fermi-Pasta-Ulam chains at zero and non-zero temperatures. While such breathers are essentially stationary and very long-lived at zero temperature, thermal fluctuations tend to lead to breather motion ... More
Self-Similarity in Random Collision ProcessesAug 08 2003Kinetics of collision processes with linear mixing rules are investigated analytically. The velocity distribution becomes self-similar in the long time limit and the similarity functions have algebraic or stretched exponential tails. The characteristic ... More
The target problem with evanescent subdiffusive trapsJul 25 2006We calculate the survival probability of a stationary target in one dimension surrounded by diffusive or subdiffusive traps of time-dependent density. The survival probability of a target in the presence of traps of constant density is known to go to ... More
Coagulation reaction in low dimensions: Revisiting subdiffusive A+A reactions in one dimensionJul 09 2009Jul 11 2009We present a theory for the coagulation reaction A+A -> A for particles moving subdiffusively in one dimension. Our theory is tested against numerical simulations of the concentration of $A$ particles as a function of time (``anomalous kinetics'') and ... More
Efficient search by optimized intermittent random walksSep 05 2009We study the kinetics for the search of an immobile target by randomly moving searchers that detect it only upon encounter. The searchers perform intermittent random walks on a one-dimensional lattice. Each searcher can step on a nearest neighbor site ... More
Stochastically driven single level quantum dot: a nano-scale finite-time thermodynamic machine and its various operational modesJan 03 2012Mar 14 2012We describe a single-level quantum dot in contact with two leads as a nanoscale finite-time thermodynamic machine. The dot is driven by an external stochastic force that switches its energy between two values. In the isothermal regime, it can operate ... More
Stokes' Drift and Hypersensitive Response with Dichotomous Markov NoiseJan 20 2005Stochastic Stokes' drift and hypersensitive transport driven by dichotomous noise are theoretically investigated. Explicit mathematical expressions for the asymptotic probability density and drift velocity are derived including the situation in which ... More
Continuous and discontinuous phase transitions and partial synchronization in stochastic three-state oscillatorsJul 20 2007We investigate both continuous (second-order) and discontinuous (first-order) transitions to macroscopic synchronization within a single class of discrete, stochastic (globally) phase-coupled oscillators. We provide analytical and numerical evidence that ... More
Effects of Disorder on Synchronization of Discrete Phase-Coupled OscillatorsNov 29 2006We study synchronization in populations of phase-coupled stochastic three-state oscillators characterized by a distribution of transition rates. We present results on an exactly solvable dimer as well as a systematic characterization of globally connected ... More
Weak disorder: anomalous transport and diffusion are normal yet againSep 09 2010Oct 15 2010Particles driven through a periodic potential by an external constant force are known to exhibit a pronounced peak of the diffusion around a critical force that defines the transition between locked and running states. It has recently been shown both ... More
Prediction of stable walking for a toy that cannot standApr 09 2001Apr 13 2001Previous experiments [M. J. Coleman and A. Ruina, Phys. Rev. Lett. 80, 3658 (1998)] showed that a gravity-powered toy with no control and which has no statically stable near-standing configurations can walk stably. We show here that a simple rigid-body ... More
The breakdown of adiabatic polaron theory in one, two, and three dimensions and the reformation of the large polaron conceptSep 11 1998We prove variationally that at weak coupling in one, two, and three dimensions there exist correlated electron-phonon states below the approximate ground states characteristically found by adiabatic polaron theory. Besides differing non-trivially in quantitative ... More
On the Generalized Kramers Problem with Exponential Memory FrictionSep 03 1998The time-dependent transmission coefficient for the generalized Kramers problem with exponential memory friction has recently been calculated by Kohen and Tannor [D. Kohen and D. J. Tannor, J. Chem. Phys. Vol. 103, 6013 (1995)] using a procedure based ... More
Polaron Effective Mass, Band Distortion, and Self-Trapping in the Holstein Molecular Crystal ModelSep 02 1998We present polaron effective masses and selected polaron band structures of the Holstein molecular crystal model in 1-D as computed by the Global-Local variational method over a wide range of parameters. These results are augmented and supported by leading ... More
Variational Inference for Data-Efficient Model Learning in POMDPsMay 23 2018Partially observable Markov decision processes (POMDPs) are a powerful abstraction for tasks that require decision making under uncertainty, and capture a wide range of real world tasks. Today, effective planning approaches exist that generate effective ... More
Estimating the J function without edge correctionOct 04 1999The interaction between points in a spatial point process can be measured by its empty space function F, its nearest-neighbour distance distribution function G, and by combinations such as the J-function $J = (1-G)/(1-F)$. The estimation of these functions ... More
Stochastic thermodynamics for a periodically driven single-particle pumpSep 28 2017We present the stochastic thermodynamic analysis of a time-periodic single particle pump, including explicit results for flux, thermodynamic force, entropy production, work, heat and efficiency. These results are valid far from equilibrium. The deviations ... More
Simulations for trapping reactions with subdiffusive traps and subdiffusive particlesNov 02 2006While there are many well-known and extensively tested results involving diffusion-limited binary reactions, reactions involving subdiffusive reactant species are far less understood. Subdiffusive motion is characterized by a mean square displacement ... More
Microtubule dynamics depart from wormlike chain modelAug 14 2007Sep 11 2007Thermal shape fluctuations of grafted microtubules were studied using high resolution particle tracking of attached fluorescent beads. First mode relaxation times were extracted from the mean square displacement in the transverse coordinate. For microtubules ... More
Pulse propagation in tapered granular chains: An analytic studyMay 27 2009We study pulse propagation in one-dimensional tapered chains of spherical granules. Analytic results for the pulse velocity and other pulse features are obtained using a binary collision approximation. Comparisons with numerical results show that the ... More
Large deviation function and fluctuation theorem for classical particle transportAug 01 2013We analytically evaluate the large deviation function in a simple model of classical particle transfer between two reservoirs. We illustrate how the asymptotic large time regime is reached starting from a special propagating initial condition. We show ... More
Noise-Driven Mechanism for Pattern FormationNov 10 2002We extend the mechanism for noise-induced phase transitions proposed by Ibanes et al. [Phys. Rev. Lett. 87, 020601-1 (2001)] to pattern formation phenomena. In contrast with known mechanisms for pure noise-induced pattern formation, this mechanism is ... More