Results for "Siegfried Auer"

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A rapidly converging algorithm for solving the Kohn-Sham and related equations in electronic structure theoryNov 13 1998We describe a rapidly converging algorithm for solving the Kohn--Sham equations and equations of similar structure that appear frequently in calculations of the structure of inhomogeneous electronic many--body systems. The algorithm has its roots the ... More
Insight into the correlation between lag time and aggregation rate in the kinetics of protein aggregationJun 09 2010Under favourable conditions, many proteins can assemble into macroscopically large aggregate's, Parkinson's and other neurological and systemic diseases. The overall process of protein aggregation is characterized by initial lag time during which no detectable ... More
Some genus 3 curves with many pointsJan 16 2002Using an explicit family of plane quartic curves, we prove the existence of a genus 3 curve over any finite field of characteristic 3 whose number of rational points stays within a fixed distance from the Hasse-Weil-Serre upper bound. We also provide ... More
Long-range photon-mediated gate scheme between nuclear spin qubits in diamondJul 30 2015Defect centers in diamond are exceptional solid-state quantum systems that can have exceedingly long electron and nuclear spin coherence times. So far, single-qubit gates for the nitrogen nuclear spin, a two-qubit gate with a nitrogen-vacancy (NV) center ... More
Differentiability of the stable norm in codimension oneMar 15 2004Dec 03 2004The real homology of a compact, n-dimensional Riemannian manifold M is naturally endowed with the stable norm. The stable norm of a homology class is the minimal Riemannian volume of its representatives. If M is orientable the stable norm on H_{n-1}(M,R) ... More
Augmented GARCH sequences: Dependence structure and asymptoticsMay 15 2008The augmented GARCH model is a unification of numerous extensions of the popular and widely used ARCH process. It was introduced by Duan and besides ordinary (linear) GARCH processes, it contains exponential GARCH, power GARCH, threshold GARCH, asymmetric ... More
Phase Diagram of alpha-Helical and beta-Sheet Forming PeptidesJun 07 2010The intrinsic property of proteins to form structural motifs such as alpha-helices and beta-sheets leads to a complex phase behavior in which proteins can assemble into various types of aggregates including crystals, liquidlike phases of unfolded or natively ... More
Entangled photons from the polariton vacuum in a switchable optical cavityDec 14 2011We study theoretically the entanglement of two-photon states in the ground state of the intersubband cavity system, the so-called polariton vacuum. The system consists of a sequence of doped quantum wells located inside a microcavity and the photons can ... More
World Summary of $α_s$ (2012)Oct 01 2012Determinations of the strong coupling strength, $\alpha_s$, are summarised and a new world average value of $\alpha_s (M_Z)$ is determined, using a new method of pre-averaging results within classes of measurements like hadronic $\tau$ decays, deep inelastic ... More
Spectral approximation of aperiodic Schrödinger operatorsOct 19 2016We study the (H\"older-)continuous behavior of the spectra belonging to a family of linear bounded operators $(A_t)_{t\in T}$ indexed by a topological space $T$. For the cases of self-adjoint, unitary and normal operators, a characterization of the continuity ... More
Analyzing and improving maximal attainable accuracy in the communication hiding pipelined BiCGStab methodSep 06 2018Pipelined Krylov subspace methods avoid communication latency by reducing the number of global synchronization bottlenecks and by hiding global communication behind useful computational work. In exact arithmetic pipelined Krylov subspace algorithms are ... More
Numerical analysis of the maximal attainable accuracy in communication hiding pipelined Conjugate Gradient methodsApr 09 2018Aug 21 2018Krylov subspace methods are widely known as efficient algebraic methods for solving large scale linear systems. However, on massively parallel hardware the performance of these methods is typically limited by communication latency rather than floating ... More
Entanglement Purification with the Exchange InteractionJan 22 2014Entanglement purification allows the creation of qubit pairs of arbitrarily high fidelity with respect to a maximally entangled state, starting from a larger number of low-fidelity pairs. Purification requires quantum memory, a role for which electron ... More
Legendre elliptic curves over finite fieldsJun 22 2001We show that every elliptic curve over a finite field of odd characteristic whose number of rational points is divisible by 4 is isogenous to an elliptic curve in Legendre form, with the sole exception of a minimal respectively maximal elliptic curve. ... More
Fundamental Limits of Energy-Efficient Resource Sharing, Power Control and Discontinuous TransmissionJul 11 2013The achievable gains via power-optimal scheduling are investigated. Under the QoS constraint of a guaranteed link rate, the overall power consumed by a cellular BS is minimized. Available alternatives for the minimization of transmit power consumption ... More
Applications of the MRI-model in sputter depth profilingJul 03 1998The physical principles of the MRI model (abbreviation for mixing-roughness- information depth) for the theoretical calculation of measured concentration- depth profiles obtained in sputter depth profiling with AES, XPS, SIMS, etc. are outlined. The main ... More
Kagome Lattice Hubbard model at half fillingFeb 26 2014Jul 22 2014We investigate the Kagome lattice Hubbard model at half-filling by variational Monte-Carlo with testing the U(1)-Dirac spin liquid, uniform and valence bond crystal states. Even for the large-$U$ case the U(1) Dirac state, being the optimal state in the ... More
Crossed products, the Mackey-Rieffel-Green machine and applicationsJun 25 2010Aug 24 2011We give an introduction into the ideal structure and representation theory of crossed products by actions of locally compact groups on C*-algebras. In particular, we discuss the Mackey-Rieffel-Green theory of induced representations of crossed products ... More
Experimental Tests of Asymptotic FreedomJun 15 2006Jun 15 2006Quantum Chromodynamics (QCD), the gauge field theory of the Strong Interaction, has specific features, asymptotic freedom and confinement, which determine the behaviour of quarks and gluons in particle reactions at high and at low energy scales. QCD predicts ... More
Eleven Years of QCD at LEPDec 21 2001Studies of hadronic final states of $e^+e^-$ annihilations, observed at the Large Electron Positron Collider LEP at CERN, are reviewed. The topics included cover measurements of $\alpha_s$, hadronic event shapes and hadronisation studies, tests of asymptotic ... More
$α_s$ at Zinnowitz 2004Jul 12 2004A review of measurements of $\alpha_s$ is given, representing the status of April 2004. The results prove the energy dependence of $\alpha_s$ and are in excellent agreement with the expectations of Quantum Chromodynamics, QCD. Evolving all results to ... More
Experimental Tests of Asymptotic FreedomSep 19 1996Measurements which probe the energy dependence of $\alpha_s$, the coupling strength of the strong interaction, are reviewed. Jet counting in $e^+ e^-$ annihilation, combining results obtained in the centre of mass energy range from 22 to 133 GeV, provides ... More
$α_s$ 2002Nov 05 2002An update of measurements of the strong coupling constant $\alpha_s$ is given, representing the status of September 2002. The results convincingly prove the energy dependence of $\alpha_s$ and are in excellent agreement with the expectations of Quantum ... More
Analyzing and improving maximal attainable accuracy in the communication hiding pipelined BiCGStab methodSep 06 2018Mar 25 2019Pipelined Krylov subspace methods avoid communication latency by reducing the number of global synchronization bottlenecks and by hiding global communication behind useful computational work. In exact arithmetic pipelined Krylov subspace algorithms are ... More
Data Preservation in High Energy Physics - why, how and when?Sep 20 2010Long-term preservation of data and software of large experiments and detectors in high energy physics is of utmost importance to secure the heritage of (mostly unique) data and to allow advanced physics (re-)analyses at later times. Summarising the work ... More
The 2009 World Average of $α_s$Aug 10 2009Aug 15 2009Measurements of $\alpha_s$, the coupling strength of the Strong Interaction between quarks and gluons, are summarised and an updated value of the world average of $\alpha_s (M_Z)$ is derived. Building up on previous reviews, special emphasis is laid on ... More
QCD Studies at LEPJun 22 2004Studies of hadronic final states of $e^+e^-$ annihilations at LEP are reviewed. The topics included cover hadronic event shapes, measurements of $\alpha_s$, determinations of QCD colour factors and tests of the non-Abelian gauge structure of QCD, differences ... More
QCD Tests at $e^+e^-$ CollidersOct 29 1997Nov 05 1997A short review of the history and a 'slide-show' of QCD tests in $e^+e^-$ annihilation is given. The world summary of measurements of $\alpha_s$ is updated.
Noisy Search with Comparative FeedbackFeb 14 2012We present theoretical results in terms of lower and upper bounds on the query complexity of noisy search with comparative feedback. In this search model, the noise in the feedback depends on the distance between query points and the search target. Consequently, ... More
Amyloid Fibril SolubilityDec 10 2015It is well established that amyloid fibril solubility is protein specific, but how solubility depends on the interactions between the fibril building blocks is not clear. Here we use a simple protein model and perform Monte Carlo simulations to directly ... More
An algorithm with nearly optimal pseudo-regret for both stochastic and adversarial banditsMay 27 2016We present an algorithm that achieves almost optimal pseudo-regret bounds against adversarial and stochastic bandits. Against adversarial bandits the pseudo-regret is $O(K\sqrt{n \log n})$ and against stochastic bandits the pseudo-regret is $O(\sum_i ... More
A Condensation-Ordering Mechanism in Nanoparticle-Catalyzed Peptide AggregationJun 07 2010Nanoparticles introduced in living cells are capable of strongly promoting the aggregation of peptides and proteins. We use here molecular dynamics simulations to characterise in detail the process by which nanoparticle surfaces catalyse the self- assembly ... More
Comparison of electricity market designs for stable decentralized power gridsApr 15 2017Apr 26 2017In this study, we develop a theoretical model of strategic equilibrium bidding and price-setting behaviour by heterogeneous and boundedly rational electricity producers and a grid operator in a single electricity market under uncertain information about ... More
From number theory to statistical mechanics: Bose-Einstein condensation in isolated trapsSep 04 1997We question the validity of the grand canonical ensemble for the description of Bose-Einstein condensation of small ideal Bose gas samples in isolated harmonic traps. While the ground state fraction and the specific heat capacity can be well approximated ... More
Maxwell's Demon at work: Two types of Bose condensate fluctuations in power-law trapsSep 04 1997Nov 17 1997After discussing the key idea underlying the Maxwell's Demon ensemble, we employ this idea for calculating fluctuations of ideal Bose gas condensates in traps with power-law single-particle energy spectra. Two essentially different cases have to be distinguished. ... More
Universality in fully developed turbulenceDec 03 1993We extend the numerical simulations of She et al. [Phys.\ Rev.\ Lett.\ 70, 3251 (1993)] of highly turbulent flow with $15 \le$ Taylor-Reynolds number $Re_\lambda\le 200$ up to $Re_\lambda \approx 45000$, employing a reduced wave vector set method (introduced ... More
Non-Commutative T-DualityJun 25 2014A duality theory of bundles of C$^*$-algebras whose fibres are twisted transformation group algebras is established. Classical T-duality is obtained as a special case, where all fibres are commutative tori, i.e. untwisted group algebras for $\Z^n$. Our ... More
Local orientations of fluctuating fluid interfacesMay 11 2005Thermal fluctuations cause the local normal vectors of fluid interfaces to deviate from the vertical direction defined by the flat mean interface position. This leads to a nonzero mean value of the corresponding polar tilt angle which renders a characterization ... More
Continuity of the spectrum of a field of self-adjoint operatorsJul 16 2015Apr 28 2016Given a family of self-adjoint operators $(A_t)_{t\in T}$ indexed by a parameter $t$ in some topological space $T$, necessary and sufficient conditions are given for the spectrum $\sigma(A_t)$ to be Vietoris continuous with respect to $t$. Equivalently ... More
Chemistry with Graphene and Graphene Oxide - Challenges for Synthetic ChemistsMay 07 2018The chemical production of graphene as well as its controlled wet- chemical modification is a challenge for synthetic chemists and the characterization of reaction products requires sophisticated analytic methods. In this review we first describe the ... More
Collective behavior of colloids due to critical Casimir interactionsNov 24 2017If colloidal solute particles are suspended in a solvent close to its critical point, they act as cavities in a fluctuating medium and thereby restrict and modify the fluctuation spectrum in a way which depends on their relative configuration. As a result ... More
On theta series attached to maximal lattices and their adjointsSep 07 2009The space spanned by theta series of adjoints of maximal even lattices of exact level $N$ and determinant $N^2$ has the Weierstrass property and hence allows to define extremality for arbitrary squarefree level $N$. We find examples of such dual extremal ... More
Numerically Stable Variants of the Communication-hiding Pipelined Conjugate Gradients Algorithm for the Parallel Solution of Large Scale Symmetric Linear SystemsJun 19 2017Sep 06 2018By reducing the number of global synchronization bottlenecks per iteration and hiding communication behind useful computational work, pipelined Krylov subspace methods achieve significantly improved parallel scalability on present-day HPC hardware. However, ... More
On the optimality of shifted Laplacian in the class of expansion preconditioners for the Helmholtz equationJan 19 2015Sep 17 2015This paper introduces and explores the class of expansion preconditioners EX(m) that forms a direct generalization to the classic complex shifted Laplace (CSL) preconditioner for Helmholtz problems. The construction of the EX(m) preconditioner is based ... More
New white dwarfs in the Hyades --Results from kinematic and photometric studiesNov 16 2011Nov 23 2011On the basis of the PPMXL catalogue (R\"oser, Demleitner & Schilbach, 2010) we searched for white dwarfs that are also member candidates of the Hyades in a region up to 40 pc from the cluster centre. We use the proper motions from PPMXL in the convergent ... More
Nonequilibrium dynamics and magnetoviscosity of moderately concentrated magnetic liquids: A dynamic mean--field studyJun 12 2003A mean-field Fokker-Planck equation approach to the dynamics of ferrofluids in the presence of a magnetic field and velocity gradients is proposed that incorporates magnetic dipole-dipole interactions of the colloidal particles. The model allows to study ... More
On geometry effects in Rayleigh-Benard convectionDec 05 2002Various recent experiments hint at a geometry dependence of scaling relations in Rayleigh-B\'enard convection. Aspect ratio and shape dependences have been found. In this paper a mechanism is offered which can account for such dependences. It is based ... More
Fractal dimension crossovers in turbulent passive scalar signalsJul 20 1993The fractal dimension $\delta_g^{(1)}$ of turbulent passive scalar signals is calculated from the fluid dynamical equation. $\delta_g^{(1)}$ depends on the scale. For small Prandtl (or Schmidt) number $Pr<10^{-2}$ one gets two ranges, $\delta_g^{(1)}=1$ ... More
Scale resolved intermittency in turbulenceJul 09 1993Aug 25 1993The deviations $\delta\zeta_m$ ("intermittency corrections") from classical ("K41") scaling $\zeta_m=m/3$ of the $m^{th}$ moments of the velocity differences in high Reynolds number turbulence are calculated, extending a method to approximately solve ... More
Nonperturbative renormalization group approach to turbulenceDec 28 1997We suggest a new, renormalization group (RG) based, nonperturbative method for treating the intermittency problem of fully developed turbulence which also includes the effects of a finite boundary of the turbulent flow. The key idea is not to try to construct ... More
Praesepe (NGC 2632) and its tidal tailsMar 20 2019Within a 400 pc sphere around the Sun, we search for Praesepe's tidal tails in the Gaia DR2 dataset. We used a modified convergent-point method to search for stars with space velocities close to the space velocity of the Praesepe cluster. We find a clear ... More
Full duality for coactions of discrete groupsSep 27 2001Using the strong relation between coactions of a discrete group G on C*-algebras and Fell bundles over G, we prove a new version of Mansfield's imprimitivity theorem for coactions of discrete groups. Our imprimitivity theorem works for the universally ... More
On fundamental Fourier coefficients of Siegel modular formsOct 01 2018We prove that if $F$ is a non-zero (possibly non-cuspidal) vector-valued Siegel modular form of any degree, then it has infinitely many non-zero Fourier coefficients which are indexed by half-integral matrices having odd, square-free (and thus fundamental) ... More
On Testing of Data-Intensive Software SystemsMar 22 2019Today's software systems like cyber-physical production systems or big data systems have to process large volumes and diverse types of data which heavily influences the quality of these so-called data-intensive systems. However, traditional software testing ... More
Variational Regret Bounds for Reinforcement LearningMay 14 2019We consider undiscounted reinforcement learning in Markov decision processes (MDPs) where both the reward functions and the state-transition probabilities may vary (gradually or abruptly) over time. For this problem setting, we propose an algorithm and ... More
Mining Patterns in Networks using HomomorphismOct 14 2011In recent years many algorithms have been developed for finding patterns in graphs and networks. A disadvantage of these algorithms is that they use subgraph isomorphism to determine the support of a graph pattern; subgraph isomorphism is a well-known ... More
On the CLT for discrete Fourier transforms of functional time seriesJun 02 2015Dec 04 2015We consider a strictly stationary and ergodic sequence of random elements taking values in some Hilbert space. Our target is to study the weak convergence of the discrete Fourier transforms under sharp conditions. As a side-result we obtain the regular ... More
On p-adic properties of Siegel modular formsMay 03 2013We show that Siegel modular forms of level \Gamma_0(p^m) are p-adic modular forms. Moreover we show that derivatives of such Siegel modular forms are p-adic. Parts of our results are also valid for vector-valued modular forms. In our approach to p-adic ... More
Structure and K-theory of crossed products by proper actionsDec 23 2010We study the C*-algebra crossed product $C_0(X)\rtimes G$ of a locally compact group $G$ acting properly on a locally compact Hausdorff space $X$. Under some mild extra conditions, which are automatic if $G$ is discrete or a Lie group, we describe in ... More
Scaling in thermal convection: A unifying theorySep 21 1999A systematic theory for the scaling of the Nusselt number $Nu$ and of the Reynolds number $Re$ in strong Rayleigh-Benard convection is suggested and shown to be compatible with recent experiments. It assumes a coherent large scale convection roll (``wind ... More
A fast and robust computational method for the ionization cross sections of the driven Schroedinger equation using an O(N) multigrid-based schemeDec 05 2014Sep 17 2015This paper improves the convergence and robustness of a multigrid-based solver for the cross sections of the driven Schroedinger equation. Adding an Coupled Channel Correction Step (CCCS) after each multigrid (MG) V-cycle efficiently removes the errors ... More
Unveiling the physics of the doped phase of the Kagome $t-J$ modelFeb 01 2013We investigate the ground state properties of the Kagome lattice $t-J$ model at low doping. We propose a new state of matter. Our results suggest an interesting phase with a balance of spin-exchange and kinetic exchange through the building blocks of ... More
A note on the normal approximation error for randomly weighted self-normalized sumsSep 27 2011Let $\bX=\{X_n\}_{n\geq 1}$ and $\bY=\{Y_n\}_{n\geq 1}$ be two independent random sequences. We obtain rates of convergence to the normal law of randomly weighted self-normalized sums $$ \psi_n(\bX,\bY)=\sum_{i=1}^nX_iY_i/V_n,\quad V_n=\sqrt{Y_1^2+...+Y_n^2}. ... More
Induced coactions of discrete groups on C*-algebrasJan 13 1998Using the close relationship between coactions of discrete groups and Fell bundles, we introduce a procedure for inducing a C*-coaction of a quotient group G/N of a discrete group G to a C*-coaction of G itself on an induced C*-algebra. We show that induced ... More
Delone dynamical systems and spectral convergenceNov 21 2017In the realm of Delone sets in locally compact, second countable, Hausdorff groups, we develop a dynamical systems approach in order to study the continuity behavior of measured quantities arising from point sets. A special focus is both on the autocorrelation, ... More
Praesepe (NGC 2632) and its tidal tailsMar 20 2019Apr 17 2019Within a 400 pc sphere around the Sun, we search for Praesepe's tidal tails in the Gaia DR2 dataset. We used a modified convergent-point method to search for stars with space velocities close to the space velocity of the Praesepe cluster. We find a clear ... More
Equivariant K-theory of finite dimensional real vector spacesMar 05 2009We give a general formula for the equivariant complex $K$-theory $K_G^*(V)$ of a finite dimensional real linear space $V$ equipped with a linear action of a compact group $G$ in terms of the representation theory of a certain double cover of $G$. Using ... More
Petersson norms of not necessarily cuspidal Jacobi modular forms and applicationsOct 01 2018We extend the usual notion of Petersson inner product on the space of cuspidal Jacobi forms to include non-cuspidal forms as well. This is done by examining carefully the relation between certain "growth-killing" invariant differential operators on $\mathbf ... More
On mod $p$ singular modular formsMay 13 2013We show that an elliptic modular form with integral Fourier coefficients in a number field $K$, for which all but finitely many coefficients are divisible by a prime ideal $\frak{p}$ of $K$, is a constant modulo $\frak{p}$. A similar property also holds ... More
Rieffel proper actionsSep 13 2014In the late 1980's Marc Rieffel introduced a notion of properness for actions of locally compact groups on C*-algebras which, among other things, allows the construction of generalised fixed-point algebras for such actions. In this paper we give a simple ... More
Weakly proper group actions, Mansfield's imprimitivity and twisted Landstad dualityOct 15 2013May 30 2014Using the theory of weakly proper actions of locally compact groups recently developed by the authors, we give a unified proof of both reduced and maximal versions of Mansfield's Imprimitivity Theorem and obtain a general version of Landstad's Duality ... More
Universal and exotic generalized fixed-point algebras for weakly proper actions and dualityApr 21 2013May 30 2014Given a C*-dynamical system (A,G,\alpha), we say that A is a weakly proper (X\rtimes G)-algebra if there exists a proper G-space X together with a nondegenerate G-equivariant *-homomorphism \phi:C_0(X)->M(A). Weakly proper G-algebras form a large subclass ... More
Analytic orbit propagation for transiting circumbinary planetsFeb 23 2015The herein presented analytical framework fully describes the motion of coplanar systems consisting of a stellar binary and a planet orbiting both stars on orbital as well as secular timescales. Perturbations of the Runge-Lenz vector are used to derive ... More
Local Fourier Analysis of the Complex Shifted Laplacian preconditioner for Helmholtz problemsDec 22 2011Sep 05 2013In this paper we solve the Helmholtz equation with multigrid preconditioned Krylov subspace methods. The class of Shifted Laplacian preconditioners are known to significantly speed-up Krylov convergence. However, these preconditioners have a parameter ... More
On the prospects of Near Earth Asteroid orbit triangulation using the Gaia satellite and Earth-based observationsSep 18 2014Accurate measurements of osculating orbital elements are essential in order to understand and model the complex dynamic behavior of Near Earth Asteroids (NEAs). ESA's Gaia mission promises to have great potential in this respect. In this article we investigate ... More
Light Microscopy: An ongoing contemporary revolutionDec 10 2014Jun 08 2015Optical microscopy is one of the oldest scientific instruments that is still used in forefront research. Ernst Abbe's nineteenth century formulation of the resolution limit in microscopy let generations of scientists believe that optical studies of individual ... More
OCR extensions - local identifiers, labeled GUIDs, file IO, and data block partitioningSep 10 2015We present several proposals for extending the Open Community Runtime (OCR) specification. The extension are identifiers with local validity, which use the concept of futures to provide OCR implementations more optimization opportunities, labeled GUIDs ... More
Non-Commutative T-DualityJun 25 2014Jul 06 2017A duality theory of bundles of C$^*$-algebras whose fibres are twisted transformation group algebras is established. Classical T-duality is obtained as a special case, where all fibres are commutative tori, i.e. untwisted group algebras for $\Z^n$. Our ... More
Imprimitivity theorems for weakly proper actions of locally compact groupsMay 22 2013Apr 04 2014In a recent paper the authors introduced universal and exotic generalized fixed-point algebras for weakly proper group actions on C*-algebras. Here we extend the notion of weakly proper actions to actions on Hilbert modules. As a result we obtain several ... More
A general Kirillov Theory for locally compact nilpotent groupsJul 27 2011We discuss a very general Kirillov Theory for the representations of certain nilpotent groups which gives a combined view an many known examples from the literature.
The classical $J_1$-$J_2$ Heisenberg model on the Kagome latticeSep 21 2011Aug 28 2012Motivated by earlier simulated annealing studies and materials with large spin on the Kagome lattice, we performed large scale parallel tempering simulations on the Kagome lattice for the extended classical Heisenberg model including next nearest neighbor ... More
Spectrum of Lebesgue measure zero for Jacobi matrices of quasicrystalsFeb 21 2013We study one-dimensional random Jacobi operators corresponding to strictly ergodic dynamical systems. In this context, we characterize the spectrum of these operators by non-uniformity of the transfer matrices and the set where the Lyapunov exponent vanishes. ... More
Thermal convection for large Prandtl numbersNov 08 2000The Rayleigh-Benard theory by Grossmann and Lohse [J. Fluid Mech. 407, 27 (2000)] is extended towards very large Prandtl numbers Pr. The Nusselt number Nu is found here to be independent of Pr. However, for fixed Rayleigh numbers Ra> 10^{10} a maximum ... More
Crossed products whose primitive ideal spaces are generalized trivial $\widehat G$-bundlesOct 12 1994We characterize when the primitive ideal space of a crossed product $\acg$ of a \cs-algebra $A$ by a locally compact abelian group $G$ is a $\sigma$-trivial $\ghat G$-space for the dual $\ghat G$-action. Specifically, we show that $\Prim(\acg)$ is $\sigma$-trivial ... More
Logarithmic temperature profiles in the ultimate regime of thermal convectionAug 13 2012We report on the theory of logarithmic temperature profiles in very strongly developed thermal convection in the geometry of a Rayleigh-Benard cell with aspect ratio one and discuss the degree of agreement with the recently measured profiles in the ultimate ... More
Doping on the kagome lattice: A variational Monte-Carlo study of the $t-J$ modelMay 03 2011Nov 11 2011We study doping on the Kagome lattice by exploring the $t-J$-model with variational Monte-Carlo. We use a number of Gutzwiller projected spin-liquid and valence bond-crystal states and compare their energies at several system-sizes. We find that introducing ... More
Rational points of the group of components of a Neron modelApr 14 1998Let A_K be an abelian variety over a discrete valuation field K. Let A be the Neron model of A_K over the ring of integers O_K of K and A_k its special fibre. We study the set of rational points of the group of components \phi_A of A_k. In particular, ... More
Wall adsorption of a colloidal particle moving in a quiescent partially wetting fluidApr 29 2003In thermal equilibrium, a colloidal particle between two parallel plates immersed in a fluid which partially wets both the particle and the plates, is attracted by the walls. However, if the particle moves parallel to the plates, a hydrodynamic lift force ... More
A note on estimation in Hilbertian linear modelsAug 14 2012Apr 16 2014We study estimation and prediction in linear models where the response and the regressor variable both take values in some Hilbert space. Our main objective is to obtain consistency of a principal components based estimator for the regression operator ... More
The communication-hiding pipelined BiCGStab method for the parallel solution of large unsymmetric linear systemsDec 05 2016Apr 24 2017A High Performance Computing alternative to traditional Krylov subspace methods, pipelined Krylov subspace solvers offer better scalability in the strong scaling limit compared to standard Krylov subspace methods for large and sparse linear systems. The ... More
Smooth parameterizations of power-subanalytic sets and compositions of Gevrey functionsMay 15 2019We show that if $X$ is an $m$-dimensional definable set in $\mathbb{R}^\text{pow}_\text{an}$, the structure of real subanalytic sets with real power maps added, then for any positive integer r there exists a $C^r$-parameterization of X consisting of $cr^{m^2}$ ... More
Generalized eigenfunctions and eigenvalues: a unifying framework for Shnol-type theoremsApr 15 2019Let $H$ be a generalized Schr\"odinger operator on a domain of a non-compact connected Riemannian manifold, and a generalized eigenfunction $u$ for $H$: that is, $u$ satisfies the equation $Hu=\lambda u$ in the weak sense but is not necessarily in $L^2$. ... More
Identifying Web Tables - Supporting a Neglected Type of Content on the WebMar 23 2015The abundance of the data in the Internet facilitates the improvement of extraction and processing tools. The trend in the open data publishing encourages the adoption of structured formats like CSV and RDF. However, there is still a plethora of unstructured ... More
Resummed effective action in the world-line formalismJun 25 2003Using the world-line method we resum the scalar one-loop effective action. This is based on an exact expression for the one-loop action obtained for a background potential and a Taylor expansion of the potential up to quadratic order in x-space. We thus ... More
On Minimizing Base Station Power ConsumptionJul 11 2013We consider resource allocation over a wireless downlink where Base Station (BS) power consumption is minimized while upholding a set of required link rates. A Power and Resource Allocation Including Sleep (PRAIS) method is proposed that combines resource ... More
A Geometric Approach to Matrix OrderingMay 23 2011We present a recursive way to partition hypergraphs which creates and exploits hypergraph geometry and is suitable for many-core parallel architectures. Such partitionings are then used to bring sparse matrices in a recursive Bordered Block Diagonal form ... More
Central twisted transformation groups and group $C^*$-algebras of central group extensionsJul 08 2002We examine the structure of central twisted transformation group \cs-algebras $C_{0}(X)\rtimes_{\id,u}G$, and apply our results to the group \cs-algebras of central group extensions. Our methods require that we study Moore's cohomology group $H^{2}\bigl(G,C(X,\T)\bigr)$, ... More
Secular Orbit Evolution in Systems with a Strong External Perturber - A Simple and Accurate ModelJan 12 2017We present a semi-analytical correction to the seminal solution for the secular motion of a planet's orbit under gravitational influence of an external perturber derived by Heppenheimer (1978). A comparison between analytical predictions and numerical ... More
Siegel Modular Forms and Theta Series attached to quaternion algebras IIOct 25 1995We continue our study of Yoshida's lifting, which associates to a pair of automorphic forms on the adelic multiplicative group of a quaternion algebra a Siegel modular form of degree 2. We consider here the case that the automorphic forms on the quaternion ... More
On the central critical value of the triple product L-functionJul 11 1995We compute the central critical value of the triple product $L$-function associated to three cusp forms $f_1,f_2,f_3$ with trivial character for groups $\Gamma_0(N_i)$ with square free levels $N_i$ not all of which are $1$ and weights $k_i$ satisfying ... More