Results for "Thomas Meier"

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The Complexity of Satisfiability for Sub-Boolean Fragments of ALCJan 24 2010Mar 29 2010The standard reasoning problem, concept satisfiability, in the basic description logic ALC is PSPACE-complete, and it is EXPTIME-complete in the presence of unrestricted axioms. Several fragments of ALC, notably logics in the FL, EL, and DL-Lite family, ... More
Generalized Satisfiability for the Description Logic ALCMar 04 2011The standard reasoning problem, concept satisfiability, in the basic description logic ALC is PSPACE-complete, and it is EXPTIME-complete in the presence of unrestricted axioms. Several fragments of ALC, notably logics in the FL, EL, and DL-Lite families, ... More
Magnetic Flux Tailoring through Lenz Lenses in Toroidal Diamond Indenter Cells: A New Pathway to High Pressure Nuclear Magnetic ResonanceMay 24 2017A new pathway to nuclear magnetic resonance spectroscopy in high pressure diamond anvil cells is introduced, using inductively coupled broadband passive electro-magnetic lenses to locally amplify the magnetic flux at the isolated sample, leading to an ... More
Vector Bundles on the Moduli Stack of Elliptic CurvesJul 31 2013Apr 20 2015We study vector bundles on the moduli stack of elliptic curves over a local ring R. If R is a field or a discrete valuation ring of (residue) characteristic not 2 or 3, all these vector bundles are sums of line bundles. For R the 3-local integers, we ... More
Spectral Sequences in String TopologyJan 27 2010Aug 08 2015In this paper, we investigate the behaviour of the Serre spectral sequence with respect to the algebraic structures of string topology in generalized homology theories, specificially with the Chas-Sullivan product and the corresponding coproduct and module ... More
A note on cabled slice knots and reducible surgeriesJul 16 2015We consider the question of when a slice knot admits a reducible Dehn surgery. By analyzing the correction terms associated to such a surgery, we show that slice knots cannot admit surgeries with more than two summands. We also give a necessary Heegaard ... More
(Topological) modular forms with level structures: decompositions and dualitySep 29 2016The present article studies decompositions of vector bundles on the moduli stack of elliptic curves that are pushforwards of vector bundles on moduli of elliptic curves with level structure. These imply decomposition results for rings of modular forms ... More
Fibration Categories are Fibrant Relative CategoriesMar 06 2015Apr 20 2015A relative category is a category with a chosen class of weak equivalences. Barwick and Kan produced a model structure on the category of all relative categories, which is Quillen equivalent to the Joyal model structure on simplicial sets and the Rezk ... More
Step size of the rotary proton motor in single FoF1-ATP synthase from a thermoalkaliphilic bacterium by DCO-ALEX FRETFeb 05 2012Thermophilic enzymes can operate at higher temperatures but show reduced activities at room temperature. They are in general more stable during preparation and, accordingly, are considered to be more rigid in structure. Crystallization is often easier ... More
Pressure induced Hydrogen-Hydrogen interaction in metallic FeH revealed by NMRFeb 08 2019Knowledge of the behavior of hydrogen in metal hydrides is the key for understanding their electronic properties. So far, no experimental methods exist to access these properties beyond 100 GPa, where high-Tc superconductivity emerges. Here, we present ... More
Thermodynamics and Spin Tunneling Dynamics in Ferric Wheels with Excess SpinJul 02 2001We study theoretically the thermodynamic properties and spin dynamics of a class of magnetic rings closely related to ferric wheels, antiferromagnetic ring systems, in which one of the Fe (III) ions has been replaced by a dopant ion to create an excess ... More
The Theory and Simulation of Relativistic Jet Formation: Towards a Unified Model For Micro- and MacroquasarsDec 02 2003I review recent progress in the theory of relativistic jet production, with special emphasis on unifying black hole sources of stellar and supermassive size. Observations of both classes of objects, as well as theoretical considerations, indicate that ... More
A Magnetically-Switched, Rotating Black Hole Model For the Production of Extragalactic Radio Jets and the Fanaroff and Riley Class DivisionOct 21 1998Jul 30 1999A model is presented in which both Fanaroff and Riley class I and II extragalactic jets are produced by magnetized accretion disk coronae in the ergospheres of rotating black holes. While the jets are produced in the accretion disk itself, the output ... More
Push is Fast on Sparse Random GraphsAug 27 2014We consider the classical push broadcast process on a large class of sparse random multigraphs that includes random power law graphs and multigraphs. Our analysis shows that for every $\varepsilon>0$, whp $O(\log n)$ rounds are sufficient to inform all ... More
Affineness and chromatic homotopy theoryNov 03 2013Jun 24 2016Given an algebraic stack $X$, one may compare the derived category of quasi-coherent sheaves on $X$ with the category of dg-modules over the dg-ring of functions on $X$. We study the analogous question in stable homotopy theory, for derived stacks that ... More
Spinc Dirac operators over the flat 3-torusMar 02 2011Apr 17 2011The aim of this paper is to study a possible "boundary phenomenon" for Spinc Dirac operators in a special case. If you parametrise Spinc Dirac operators by a family of connections on a Spinc 4-manifold with boundary, this boundary inherits also a family ... More
Quantum Critical Dynamics Simulation of Dirty Boson SystemsSep 14 2011Nov 23 2011Recently the scaling result $z=d$ for the dynamic critical exponent at the Bose glass to superfluid quantum phase transition has been questioned both on theoretical and numerical grounds. This motivates a careful evaluation of the critical exponents in ... More
Symbolic Dynamics, Partial Dynamical Systems, Boolean Algebras and C*-algebras Generated by Partial IsometriesApr 07 2006Oct 12 2006We associate to each discrete partial dynamical system a universal C*-algebra generated by partial isometries satisfying relations given by a Boolean algebra connected to the discrete partial dynamical system in question. We show that for symbolic dynamical ... More
Cuntz-Pimsner C*-algebras associated with subshiftsMay 24 2005Nov 16 2005By using C*-correspondences and Cuntz-Pimsner algebras, we associate to every subshift (also called a shift space) $X$ a C*-algebra $O_X$, which is a generalization of the Cuntz-Krieger algebras. We show that $O_X$ is the universal C*-algebra generated ... More
The cohomology of right angled Artin groups with group ring coefficientsJan 15 2004Feb 27 2004We give an explicit formula for the cohomology of a right angled Artin group with group ring coefficients in terms of the cohomology of its defining flag complex.
Non-CMC Solutions to the Einstein Constraint Equations on Asymptotically Euclidean Manifolds with Apparent Horizon BoundariesMar 18 2014In this article we further develop the solution theory for the Einstein constraint equations on an n-dimensional, asymptotically Euclidean manifold M with interior boundary S. Building on recent results for both the asymptotically Euclidean and compact ... More
The Brauer group of the moduli stack of elliptic curvesAug 02 2016We compute the Brauer group of the moduli stack of elliptic curves over the integers and over localizations of the integers. The methods involved include the descent spectral sequence in \'etale cohomology, group cohomology calculations for S3, the classification ... More
Bridge trisections of knotted surfaces in $S^4$Jul 30 2015We introduce bridge trisections of knotted surfaces in the four-sphere. This description is inspired by the work of Gay and Kirby on trisections of four-manifolds and extends the classical concept of bridge splittings of links in the three-sphere to four ... More
Dynamics of short time--scale energy relaxation of optical excitations due to electron--electron scattering in the presence of arbitrary disorderNov 11 2002Apr 11 2003A non--equilibrium occupation distribution relaxes towards the Fermi--Dirac distribution due to electron--electron scattering even in finite Fermi systems. The dynamic evolution of this thermalization process assumed to result from an optical excitation ... More
The Complexity of Reasoning for Fragments of Default LogicAug 28 2008Aug 23 2010Default logic was introduced by Reiter in 1980. In 1992, Gottlob classified the complexity of the extension existence problem for propositional default logic as $\SigmaPtwo$-complete, and the complexity of the credulous and skeptical reasoning problem ... More
On the Parameterized Complexity of Default Logic and Autoepistemic LogicOct 04 2011Oct 06 2011We investigate the application of Courcelle's Theorem and the logspace version of Elberfeld etal. in the context of the implication problem for propositional sets of formulae, the extension existence problem for default logic, as well as the expansion ... More
Observation of Nuclear Quantum Effects and Hydrogen Bond Symmetrisation in High Pressure IceMar 19 2018Hydrogen bond symmetrisations in H-bonded systems triggered by pressure induced nuclear quantum effects (NQEs) is a long-known concept1 but experimental evidences in high-pressure ices have remained elusive with conventional methods2,3. Theoretical works ... More
Misconceptions About General Relativity in Theoretical Black Hole AstrophysicsApr 09 2010The fundamental role played by black holes in our study of microquasars, gamma ray bursts, and the outflows from active galactic nuclei requires an appreciation for, and at times some in-depth analysis of, curved spacetime. We highlight misconceptions ... More
The $C_2$-spectrum $Tmf_1(3)$ and its invertible modulesJul 29 2015Dec 07 2016We explore the $C_2$-equivariant spectra $Tmf_1(3)$ and $TMF_1(3)$. In particular, we compute their $C_2$-equivariant Picard groups and the $C_2$-equivariant Anderson dual of $Tmf_1(3)$. This implies corresponding results for the fixed point spectra $TMF_0(3)$ ... More
Analysis of NMR Spin-Lattice Relaxation Rates in CupratesFeb 02 2005Jul 04 2005We investigate nuclear spin-lattice relaxation data in the normal state of optimally doped YBaCuO_7 by analyzing the contributions to the relaxation rate of the copper, planar oxygen and yttrium along the directions perpendicular to the applied field. ... More
C*-crossed products and shift spacesDec 21 2005In this article, we use Exel's construction to associate a C*-algebra to every shift space. We show that it has the C*-algebra defined in [Carlsen and Matsumoto: Some remarks on the C*-algebras associated with subshifts] as a quotient, and possesses properties ... More
Sign change in the tunnel magnetoresistance of Fe3O4/MgO/Co-Fe-B magnetic tunnel junctions depending on the annealing temperature and the interface treatmentDec 23 2014Apr 10 2015Magnetite (Fe3O4) is an eligible candidate for magnetic tunnel junctions (MTJs) since it shows a high spin polarization at the Fermi level as well as a high Curie temperature of 585{\deg}C. In this study, Fe3O4/MgO/Co-Fe-B MTJs were manufactured. A sign ... More
Dynamic Virtualized Deployment of Particle Physics Environments on a High Performance Computing ClusterDec 20 2018The NEMO High Performance Computing Cluster at the University of Freiburg has been made available to researchers of the ATLAS and CMS experiments. Users access the cluster from external machines connected to the World-wide LHC Computing Grid (WLCG). This ... More
Neuromorphic Learning towards Nano Second PrecisionSep 17 2013Sep 18 2013Temporal coding is one approach to representing information in spiking neural networks. An example of its application is the location of sounds by barn owls that requires especially precise temporal coding. Dependent upon the azimuthal angle, the arrival ... More
The Complexity of Reasoning for Fragments of Autoepistemic LogicJun 01 2010Autoepistemic logic extends propositional logic by the modal operator L. A formula that is preceded by an L is said to be "believed". The logic was introduced by Moore 1985 for modeling an ideally rational agent's behavior and reasoning about his own ... More
The Complexity of Propositional ImplicationNov 06 2008Aug 12 2009The question whether a set of formulae G implies a formula f is fundamental. The present paper studies the complexity of the above implication problem for propositional formulae that are built from a systematically restricted set of Boolean connectives. ... More
Diagonal-preserving graded isomorphisms of Steinberg algebrasNov 29 2016We study Steinberg algebras constructed from ample Hausdorff groupoids over commutative integral domains with identity. We reconstruct graded groupoids from graded Steinberg algebras and use this to characterise when there is a diagonal-preserving graded ... More
On the Exel crossed product of topological covering mapsNov 01 2008For dynamical systems defined by a covering map of a compact Hausdorff space and the corresponding transfer operator, the associated crossed product $C^*$-algebras $\cros$ introduced by Exel and Vershik are considered. An important property for homeomorphism ... More
The Complexity of Satisfiability for Fragments of Hybrid Logic -- Part IJun 08 2009The satisfiability problem of hybrid logics with the downarrow binder is known to be undecidable. This initiated a research program on decidable and tractable fragments. In this paper, we investigate the effect of restricting the propositional part of ... More
NMR close to Mega-Bar PressuresMar 14 2018The past 15 years have seen an astonishing increase in Nuclear Magnetic Resonance (NMR) sensitivity and accessible pressure range in high-pressure NMR experiments, owing to a series of new developments of NMR spectroscopy applied to the diamond anvil ... More
Model Checking CTL is Almost Always Inherently SequentialMar 25 2011Nov 15 2011The model checking problem for CTL is known to be P-complete (Clarke, Emerson, and Sistla (1986), see Schnoebelen (2002)). We consider fragments of CTL obtained by restricting the use of temporal modalities or the use of negations---restrictions already ... More
The Complexity of Monotone Hybrid Logics over Linear Frames and the Natural NumbersApr 05 2012Jun 12 2012Hybrid logic with binders is an expressive specification language. Its satisfiability problem is undecidable in general. If frames are restricted to N or general linear orders, then satisfiability is known to be decidable, but of non-elementary complexity. ... More
Quantum Spin Dynamics in Molecular MagnetsMay 22 2002The detailed theoretical understanding of quantum spin dynamics in various molecular magnets is an important step on the roadway to technological applications of these systems. Quantum effects in both ferromagnetic and antiferromagnetic molecular clusters ... More
Geometrically Exact Finite Element Formulations for Curved Slender Beams: Kirchhoff-Love Theory vs. Simo-Reissner TheorySep 01 2016The present work focuses on geometrically exact finite elements for highly slender beams. It aims at the proposal of novel formulations of Kirchhoff-Love type, a detailed review of existing formulations of Kirchhoff-Love and Simo-Reissner type as well ... More
Orbit equivalence of graphs and isomorphism of graph groupoidsOct 31 2016Nov 01 2016We show that the groupoids of two directed graphs are isomorphic if and only if the two graphs are orbit equivalent by an orbit equivalence that preserves isolated eventually periodic points. We also give a complete description of the (topological) isolated ... More
On Chase Termination Beyond StratificationJun 23 2009Sep 17 2009We study the termination problem of the chase algorithm, a central tool in various database problems such as the constraint implication problem, Conjunctive Query optimization, rewriting queries using views, data exchange, and data integration. The basic ... More
Cuntz-Krieger algebras and one-sided conjugacy of shifts of finite type and their groupoidsDec 01 2017A one-sided shift of finite type $(X_A,\sigma_A)$ determines on the one hand a Cuntz-Krieger algebra $\mathcal{O}_A$ with a distinguished abelian subalgebra $\mathcal{D}_A$ and a certain completely positive map $\tau_A$ on $\mathcal{O}_A$. On the other ... More
Determining the optimal locations for shock acceleration in magnetohydrodynamical jetsSep 15 2010Observations of relativistic jets from black holes systems suggest that particle acceleration often occurs at fixed locations within the flow. These sites could be associated with critical points that allow the formation of standing shock regions, such ... More
$C^*$-algebras associated to Boolean dynamical systemsOct 22 2015Feb 08 2016The goal of these notes is to present the C*-algebra $C^*(B,L,\theta)$ of a Boolean dynamical system $(B,L,\theta)$, that generalizes the $C^*$-algebra associated to Labelled graphs introduced by Bates and Pask, and to determine its simplicity, its gauge ... More
A Finite Element Approach for the Line-to-Line Contact Interaction of Thin Beams with Arbitrary OrientationMar 30 2016The objective of this work is the development of a novel finite element formulation describing the contact interaction of slender beams in complex 3D configurations involving arbitrary beam-to-beam orientations. It is shown in a mathematically concise ... More
Apate - A Linux Kernel Module for High Interaction HoneypotsJul 11 2015Honeypots are used in IT Security to detect and gather information about ongoing intrusions, e.g., by documenting the approach of an attacker. Honeypots do so by presenting an interactive system that seems just like a valid application to an attacker. ... More
Equivalence and stable isomorphism of groupoids, and diagonal-preserving stable isomorphisms of graph C*-algebras and Leavitt path algebrasFeb 08 2016Sep 14 2016We prove that ample groupoids with sigma-compact unit spaces are equivalent if and only if they are stably isomorphic in an appropriate sense, and relate this to Matui's notion of Kakutani equivalence. We use this result to show that diagonal-preserving ... More
Non-Commutative Representations of Families of k^2 Commutative Polynomials in 2k^2 Commuting VariablesDec 04 2012Given a collection P of k^2 commutative polynomials in 2k^2 commutative variables, the objective is to find a condensed representation of these polynomials in terms of a single non-commutative polynomial p(X,Y) in two k x k matrix variables X and Y. Algorithms ... More
Gorenstein duality for Real spectraJul 08 2016Following Hu and Kriz, we study the $C_2$-spectra $BP\mathbb{R}\langle n \rangle$ and $E\mathbb{R}(n)$ that refine the usual truncated Brown-Peterson and the Johnson-Wilson spectra. In particular, we show that they satisfy Gorenstein duality with a representation ... More
A Unified Approach for Beam-to-Beam ContactJul 29 2016Existing beam contact formulations can be categorized in point contact models that consider a discrete contact force at the closest point of the beams, and line contact models that assume distributed contact forces. In this work, it will be shown that ... More
$C^*$-algebras of labelled graphs III - $K$-theory computationsMar 14 2012Jan 20 2015In this paper we give a formula for the $K$-theory of the $C^*$-algebra of a weakly left-resolving labelled space. This is done by realising the $C^*$-algebra of a weakly left-resolving labelled space as the Cuntz-Pimsner algebra of a $C^*$-correspondence. ... More
Stop the ChaseJan 26 2009May 06 2009The chase procedure, an algorithm proposed 25+ years ago to fix constraint violations in database instances, has been successfully applied in a variety of contexts, such as query optimization, data exchange, and data integration. Its practicability, however, ... More
Foundations of SPARQL Query OptimizationDec 19 2008Jan 26 2009The SPARQL query language is a recent W3C standard for processing RDF data, a format that has been developed to encode information in a machine-readable way. We investigate the foundations of SPARQL query optimization and (a) provide novel complexity ... More
Bayesian Nonparametric Analysis of Multivariate Time Series: A Matrix Gamma Process ApproachNov 26 2018While there is an increasing amount of literature about Bayesian time series analysis, only a few Bayesian nonparametric approaches to multivariate time series exist. Most methods rely on Whittle's Likelihood, involving the second order structure of a ... More
Propagation of Coulomb-correlated electron-hole pairs in semiconductors with correlated and anticorrelated disorderFeb 28 2000Local ultrafast optical excitation of electron-hole pairs in disordered semiconductors provides the possibility to observe experimentally interaction-assisted propagation of correlated quantum particles in a disordered environment. In addition to the ... More
Interacting electrons in a one-dimensional random array of scatterers - A Quantum Dynamics and Monte-Carlo studyMar 28 2002The quantum dynamics of an ensemble of interacting electrons in an array of random scatterers is treated using a new numerical approach for the calculation of average values of quantum operators and time correlation functions in the Wigner representation. ... More
Joule heating in nanowiresDec 20 2010Aug 30 2011We study the effect of Joule heating from electric currents flowing through ferromagnetic nanowires on the temperature of the nanowires and on the temperature of the substrate on which the nanowires are grown. The spatial current density distribution, ... More
Is a 4-bit synaptic weight resolution enough? - Constraints on enabling spike-timing dependent plasticity in neuromorphic hardwareJan 30 2012Nov 28 2014Large-scale neuromorphic hardware systems typically bear the trade-off between detail level and required chip resources. Especially when implementing spike-timing-dependent plasticity, reduction in resources leads to limitations as compared to floating ... More
Optically induced coherent intra-band dynamics in disordered semiconductorsNov 21 2001On the basis of a tight-binding model for a strongly disordered semiconductor with correlated conduction- and valence band disorder a new coherent dynamical intra-band effect is analyzed. For systems that are excited by two, specially designed ultrashort ... More
Microscopic modeling of photoluminescence of strongly disordered semiconductorsMay 09 2005Feb 07 2006A microscopic theory for the luminescence of ordered semiconductors is modified to describe photoluminescence of strongly disordered semiconductors. The approach includes both diagonal disorder and the many-body Coulomb interaction. As a case study, the ... More
Dynamics of Coulomb-correlated electron-hole pairs in disordered semiconductor nanowiresNov 23 2001The dynamics of optically generated electron-hole pairs is investigated in a disordered semiconductor nanowire. The particle pairs are generated by short laser pulses and their dynamics is followed using the Heisenberg equation of motion. Is is shown ... More
Signatures of Many-Particle Correlations in Two-Dimensional Fourier-Transform Spectra of Semiconductor NanostructuresFeb 05 2007On the basis of a microscopic theory, the signatures of many-particle correlations in Two-Dimensional Fourier-Transform Spectra (2D-FTS) of semiconductor nanostructures are identified and compared to experimental data. Spectra in the photon energy range ... More
The effect of heterogeneity on decorrelation mechanisms in spiking neural networks: a neuromorphic-hardware studyNov 28 2014Jun 09 2016High-level brain function such as memory, classification or reasoning can be realized by means of recurrent networks of simplified model neurons. Analog neuromorphic hardware constitutes a fast and energy efficient substrate for the implementation of ... More
Measuring the Attenuation Length of Water in the CHIPS-M Water Cherenkov DetectorOct 21 2016Nov 19 2016The water at the proposed site of the CHIPS water Cherenkov detector has been studied to measure its attenuation length for Cherenkov light as a function of filtering time. A scaled model of the CHIPS detector filled with water from the Wentworth 2W pit, ... More
Generalized Complexity of ALC SubsumptionMay 03 2012The subsumption problem with respect to terminologies in the description logic ALC is EXPTIME-complete. We investigate the computational complexity of fragments of this problem by means of allowed Boolean operators. Hereto we make use of the notion of ... More
Anisotropy of the antiferromagnetic spin correlations in the superconducting state of YBa_2Cu_3O_7 and YBa_2Cu_4O_8Jun 10 2005Oct 12 2005We present evidence that the antiferromagnetic spin correlations in optimally doped YBa_2Cu_3O_7 and underdoped YBa_2Cu_4O_8 develop a surprisingly strong anisotropy in the superconducting state. Comparing the ratio of the nuclear spin-lattice relaxation ... More
A generalized topological recursion for arbitrary ramificationAug 29 2012The Eynard-Orantin topological recursion relies on the geometry of a Riemann surface S and two meromorphic functions x and y on S. To formulate the recursion, one must assume that x has only simple ramification points. In this paper we propose a generalized ... More
Emulating quantum computation with artificial neural networksOct 24 2018We demonstrate, that artificial neural networks (ANN) can be trained to emulate single or multiple basic quantum operations. In order to realize a quantum state, we implement a novel "quantumness gate" that maps an arbitrary matrix to the real representation ... More
Predicting GradesAug 16 2015Mar 18 2016To increase efficacy in traditional classroom courses as well as in Massive Open Online Courses (MOOCs), automated systems supporting the instructor are needed. One important problem is to automatically detect students that are going to do poorly in a ... More
Inducing strong convergence into the asymptotic behaviour of proximal splitting algorithms in Hilbert spacesSep 06 2016Nov 18 2017Proximal splitting algorithms for monotone inclusions (and convex optimization problems) in Hilbert spaces share the common feature to guarantee for the generated sequences in general weak convergence to a solution. In order to achieve strong convergence, ... More
Cyanoacetylene in IC 342: An Evolving Dense Gas Component with Starburst AgeMay 09 2011We present the first images of the J=5-4 and J=16-15 lines of the dense gas tracer, cyanoacetylene, HC_3N, in an external galaxy. The central 200 pc of the nearby star-forming spiral galaxy, IC 342, was mapped using the VLA and the Plateau de Bure Interferometer. ... More
Finitely additive beliefs and universal type spacesFeb 28 2006The probabilistic type spaces in the sense of Harsanyi [Management Sci. 14 (1967/68) 159--182, 320--334, 486--502] are the prevalent models used to describe interactive uncertainty. In this paper we examine the existence of a universal type space when ... More
A computer controlled pendulum with position readoutMay 13 2009We have designed, built and operated a physical pendulum which allows one to demonstrate experimentally the behaviour of the pendulum under any equation of motion for such a device for any initial conditions. All parameters in the equation of motion can ... More
Beyond Whittle: Nonparametric correction of a parametric likelihood with a focus on Bayesian time series analysisJan 17 2017The Whittle likelihood is widely used for Bayesian nonparametric estimation of the spectral density of stationary time series. However, the loss of efficiency for non-Gaussian time series can be substantial. On the other hand, parametric methods are more ... More
Distinguishing topologically and smoothly doubly slice knotsJan 06 2014Nov 03 2014We construct an infinite family of smoothly slice knots that we prove are topologically doubly slice. Using the correction terms coming from Heegaard Floer homology, we show that none of these knots is smoothly doubly slice. We use these knots to show ... More
Time-optimal navigation through quantum windOct 24 2014Feb 19 2015The quantum navigation problem of finding the time-optimal control Hamiltonian that transports a given initial state to a target state through quantum wind, that is, under the influence of external fields or potentials, is analysed. By lifting the problem ... More
The Magnetorotational Instability in Core Collapse Supernova ExplosionsAug 06 2002Dec 05 2002We investigate the action of the magnetorotational instability (MRI) in the context of iron-core collapse. Exponential growth of the field on the rotation time scale by the MRI will dominate the linear growth process of field line "wrapping" with the ... More
Object Recognition with Multi-Scale Pyramidal Pooling NetworksJul 07 2012We present a Multi-Scale Pyramidal Pooling Network, featuring a novel pyramidal pooling layer at multiple scales and a novel encoding layer. Thanks to the former the network does not require all images of a given classification task to be of equal size. ... More
Physics Performance with the CMS Pixel DetectorDec 17 2014A large fraction of the results produced by the LHC experiments during the first run were made possible by precision vertexing detectors. The all-silicon tracking detector of the CMS experiment uses a pixel detector to do vertexing. This conference report ... More
First Alignment of the Complete CMS TrackerMar 12 2010This conference proceeding presents the first results of the full CMS Tracker alignment based on several million reconstructed tracks from the cosmic data taken during the commissioning runs with the detector in its final position and magnetic field present. ... More
Spin dynamics in HTSC cuprates: The singlet--correlated band (or t-J-V) model and its applicationsSep 05 2005So far calculations of the spin susceptibility in the superconducting state of cuprates have been performed in the framework of weak-coupling approximations. However, it is known that cuprates belong to Mott-Hubbard doped materials where electron correlations ... More
Graph algebras and orbit equivalenceOct 08 2014We introduce the notion of orbit equivalence of directed graphs, following Matsumoto's notion of continuous orbit equivalence for topological Markov shifts. We show that two graphs in which every cycle has an exit are orbit equivalent if and only if there ... More
Learning Sensor Feedback Models from Demonstrations via Phase-Modulated Neural NetworksOct 24 2017Mar 15 2018In order to robustly execute a task under environmental uncertainty, a robot needs to be able to reactively adapt to changes arising in its environment. The environment changes are usually reflected in deviation from expected sensory traces. These deviations ... More
Small Seifert fibered surgery on hyperbolic pretzel knotsOct 29 2012Jul 23 2013We complete the classification of hyperbolic pretzel knots admitting Seifert fibered surgeries. This is the final step in understanding all exceptional surgeries on hyperbolic pretzel knots. We also present results toward similar classifications for non-pretzel ... More
Gas Bubbles Emerging from a Submerged Granular BedOct 16 2009This fluid dynamics video was submitted to the Gallery of Fluid Motion for the 2009 APS Division of Fluid Dynamics Meeting in Minneapolis, Minnesota. In this video we show some results from a simple experiment where air was injected by a single nozzle ... More
Magnetically-Dominated Accretion Flows (MDAFs) and Jet Production in the Low/Hard STateApr 22 2005In this paper I propose that the inner part of a black hole accretion inflow ($< 100 r_{g}$) may enter a magnetically-dominated, magnetosphere-like phase in which the strong, well-ordered fields play a more important role than weak, turbulent fields. ... More
Geometrically exact beam elements and smooth contact schemes for the modeling of fiber-based materials and structuresNov 19 2016Recently, the authors have proposed a novel all-angle beam contact (ABC) formulation that combines the advantages of existing point and line contact models in a variationally consistent manner. However, the ABC formulation has so far only been applied ... More
Reconstruction of groupoids and C*-rigidity of dynamical systemsNov 03 2017We show how to construct a graded locally compact Hausdorff \'etale groupoid from a C*-algebra carrying a coaction of a discrete group, together with a suitable abelian subalgebra. We call this groupoid the extended Weyl groupoid. When the coaction is ... More
Characterization of Disorder in Semiconductors via Single-Photon InterferometryNov 15 2006The method of angular photonic correlations of spontaneous emission is introduced as an experimental, purely optical scheme to characterize disorder in semiconductor nanostructures. The theoretical expression for the angular correlations is derived and ... More
CHerenkov detectors In mine PitS (CHIPS) Letter of Intent to FNALJul 23 2013Sep 23 2013This Letter of Intent outlines a proposal to build a large, yet cost-effective, 100 kton fiducial mass water Cherenkov detector that will initially run in the NuMI beam line. The CHIPS detector (CHerenkov detector In Mine PitS) will be deployed in a flooded ... More
On the quantifier-free dynamic complexity of ReachabilityJun 13 2013Jan 28 2015The dynamic complexity of the reachability query is studied in the dynamic complexity framework of Patnaik and Immerman, restricted to quantifier-free update formulas. It is shown that, with this restriction, the reachability query cannot be dynamically ... More
Infinite reduced words and the Tits boundary of a Coxeter groupJan 05 2013Sep 18 2014Let (W,S) be a finite rank Coxeter system with W infinite. We prove that the limit weak order on the blocks of infinite reduced words of W is encoded by the topology of the Tits boundary of the Davis complex X of W. We consider many special cases, including ... More
How deals with discrete data for the reduction of simulation models using neural networkJun 10 2009Simulation is useful for the evaluation of a Master Production/distribution Schedule (MPS). Also, the goal of this paper is the study of the design of a simulation model by reducing its complexity. According to theory of constraints, we want to build ... More
Two-Variable Logic with Two Order RelationsOct 07 2011Mar 03 2012It is shown that the finite satisfiability problem for two-variable logic over structures with one total preorder relation, its induced successor relation, one linear order relation and some further unary relations is EXPSPACE-complete. Actually, EXPSPACE-completeness ... More
Thermodynamic formalism for transport coefficients with an application to the shear modulus and shear viscosityDec 07 2016We discuss Onsager's thermodynamic formalism for transport coefficients and apply it to the calculation of the shear modulus and shear viscosity of a monodisperse system of repulsive particles. We focus on the concept of extensive "distance" and intensive ... More