Results for "Sören Dörscher"

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Lattice-induced photon scattering in an optical lattice clockFeb 08 2018We investigate scattering of lattice laser radiation in a strontium optical lattice clock and its implications for operating clocks at interrogation times up to several ten seconds. Rayleigh scattering does not cause significant decoherence of the atomic ... More
Creation of Quantum-Degenerate Gases of Ytterbium in a Compact 2D-/3D-MOT SetupMar 05 2013We report on the first experimental setup based on a 2D-/3D-MOT scheme to create both Bose-Einstein condensates and degenerate Fermi gases of several ytterbium isotopes. Our setup does not require a Zeeman slower and offers the flexibility to simultaneously ... More
Noise and instability of an optical lattice clockJul 17 2015Nov 03 2015We present an analysis of the different types of noise from the detection and interrogation laser in our strontium lattice clock. We develop a noise model showing that in our setup quantum projection noise--limited detection is possible if more than 130~atoms ... More
Optimal decision under ambiguity for diffusion processesOct 18 2011Oct 18 2012In this paper we consider stochastic optimization problems for an ambiguity averse decision maker who is uncertain about the parameters of the underlying process. In a first part we consider problems of optimal stopping under drift ambiguity for one-dimensional ... More
Barbero's Hamiltonian derived from a generalized Hilbert-Palatini actionNov 07 1995Barbero recently suggested a modification of Ashtekar's choice of canonical variables for general relativity. Although leading to a more complicated Hamiltonian constraint this modified version, in which the configuration variable still is a connection, ... More
On the Solution of General Impulse Control Problems Using Superharmonic FunctionsApr 12 2013Sep 19 2013In this paper, a characterization of the solution of impulse control problems in terms of superharmonic functions is given. In a general Markovian framework, the value function of the impulse control problem is shown to be the minimal function in a convex ... More
A method for pricing American options using semi-infinite linear programmingMar 23 2011Jun 09 2011We introduce a new approach for the numerical pricing of American options. The main idea is to choose a finite number of suitable excessive functions (randomly) and to find the smallest majorant of the gain function in the span of these functions. The ... More
An Application of Periodic Unfolding on ManifoldsJun 10 2013We show how the newly developed method of Periodic Unfolding on Riemannian manifolds can be applied to PDE problems: We consider the homogenization of an elliptic model problem. In the limit, we obtain a generalization of the well-known limit- and cell-problem. ... More
Phasetype distributions, autoregressive processes and overshootAug 04 2010Autoregressive processes are intensively studied in statistics and other fields of applied stochastics. For many applications the overshoot and the threshold-time are of special interest. When the upward innovations are in the class of phasetype distributions ... More
Geometric Set Cover and Hitting Sets for Polytopes in $R^3$Feb 20 2008Suppose we are given a finite set of points $P$ in $\R^3$ and a collection of polytopes $\mathcal{T}$ that are all translates of the same polytope $T$. We consider two problems in this paper. The first is the set cover problem where we want to select ... More
Gott time machines in the Anti-de Sitter spaceJan 12 1995In 1991 Gott presented a solution of Einstein's field equations in 2+1 dimensions with $\Lambda = 0$ that contained closed timelike curves (CTC's). This solution was remarkable because at first it did not seem to be unphysical in any other respect. Later, ... More
Generalized Fibonacci Numbers and Blackwell's Renewal TheoremDec 22 2010We investigate a connection between generalized Fibonacci numbers and renewal theory for stochastic processes. Using Blackwell's renewal theorem we find an approximation to the generalized Fibonacci numbers. With the help of error estimates in the renewal ... More
On the Beavers-Joseph-Saffman boundary condition for curved interfacesApr 22 2015The appropriate boundary condition between an unconfined incompressible viscous fluid and a porous medium is given by the law of Beavers and Joseph. The latter has been justified both experimentally and mathematically, using the method of periodic homogenisation. ... More
Hartree-Fock Corrections in a Mean-field Limit for FermionsSep 15 2016We consider the many-body dynamics of fermions with Coulomb interaction in a mean-field scaling limit where the kinetic and potential energy are of the same order for large particle numbers. In the considered limit the spatial variation of the mean-field ... More
Radial multipliers on amalgamated free products of II_1-factorsJun 24 2013Dec 18 2013Let $\mathcal{M}_i$ be a family of $\mathrm{II}_1$-factors, containing a common $\mathrm{II}_1$-subfactor $\mathcal{N}$, such that $[\mathcal{M}_i:\mathcal{N}] \in \mathbb{N}_0$ for all $i$. Furthermore, let $\phi \colon \mathbb{N}_0 \to \mathbb{C}$. ... More
Equivariant bifurcations in $4$-dimensional fixed point spacesNov 02 2015Jul 11 2016In this paper we continue the study of group representations which are counterexamples to the Ize conjecture. As in the previous papers by Lauterbach [14] and Lauterbach & Matthews [15] we find new infinite series of finite groups leading to such counterexamples. ... More
Impulse control and expected supremaMar 04 2015Nov 04 2015We consider a class of impulse control problems for general underlying strong Markov processes on the real line, which allows for an explicit solution. The optimal impulse times are shown to be of threshold type and the optimal threshold is characterized ... More
Distributed Convex Optimization with Many Convex ConstraintsOct 07 2016We address the problem of solving convex optimization problems with many convex constraints in a distributed setting. Our approach is based on an extension of the alternating direction method of multipliers (ADMM) that recently gained a lot of attention ... More
Collectivity in small collision systems : an initial state perspectiveNov 01 2016Measurements of multi-particle correlations in the collisions of small systems such as $p+p$, $p/d/^3He+A$ show striking similarity to the observations in heavy ion collisions. A number of observables measured in the high multiplicity events of these ... More
Notes on the Cluster Gutzwiller Method: Inhomogeneous Lattices, Excitations, and Cluster Time EvolutionAug 09 2016Several perspectives of the cluster Gutzwiller method are briefly discussed. I show that the cluster mean-field method can be used for large inhomogeneous lattices, for computing local excitations, and for the time evolution of correlated quantum systems. ... More
Riesz representation and optimal stopping with two case studiesSep 10 2013Oct 20 2015In this paper we demonstrate that the Riesz representation of excessive functions is a useful and enlightening tool to study optimal stopping problems. After a short general discussion of the Riesz representation we concretize, firstly, on a d-dimensional ... More
Extrinsic curvature of codimension one isometric immersions with Hölder continuous derivativesJan 22 2016Sep 14 2016We prove that if $n$ is even, $(M,g)$ is a compact $n$-dimensional Riemannian manifold whose Pfaffian form is a positive multiple of the volume form, and $y\in C^{1,\alpha}(M;\mathbb{R}^{n+1})$ is an isometric immersion with $n/(n+1)< \alpha\leq 1$, then ... More
Optimal relaxed portfolio strategies for growth rate maximization problems with transaction costsSep 03 2012Jun 07 2013In this paper we investigate a new class of growth rate maximization problems based on impulse control strategies such that the average number of trades per time unit does not exceed a fixed level. Moreover, we include proportional transaction costs to ... More
Radial multipliers on reduced free products of operator algebrasJan 03 2012Jan 04 2012Let A_i be a family of unital C*-algebras, respectively, of von Neumann algebras and phi: N_0 \to C. We show that if a Hankel matrix related to phi is trace-class, then there exists a unique completely bounded map M_phi on the reduced free product of ... More
Branching within branching II: Limit theoremsMay 15 2015This continues work started in part I on a general branching-within-branching model for host-parasite co-evolution. Here we focus on asymptotic results for relevant processes in the case when parasites survive. In particular, limit theorems for the processes ... More
The law of large numbers for the free multiplicative convolutionNov 19 2012Apr 08 2013In classical probability the law of large numbers for the multiplicative convolution follows directly from the law for the additive convolution. In free probability this is not the case. The free additive law was proved by D. Voiculescu in 1986 for probability ... More
Dirac and Laplace operators on some non-orientable conformally flat manifoldsFeb 21 2011In this paper we present an explicit construction for the fundamental solution to the Dirac and Laplace operator on some non-orientable conformally flat manifolds. We first treat a class of projective cylinders and tori where we can study monogenic sections ... More
Convergence of switching diffusionsMar 04 2014Nov 26 2014This paper studies the asymptotic behavior of processes with switching. More precisely, the stability under fast switching for diffusion processes and discrete state space Markovian processes is considered. The proofs are based on semimartingale techniques, ... More
A New Method and a New Scaling For Deriving Fermionic Mean-field DynamicsSep 01 2014Jan 11 2016We introduce a new method for deriving the time-dependent Hartree or Hartree-Fock equations as an effective mean-field dynamics from the microscopic Schroedinger equation for fermionic many-particle systems in quantum mechanics. The method is an adaption ... More
Twisted superfluid phase in the extended one-dimensional Bose-Hubbard modelMay 17 2016Jul 21 2016In one-dimensional systems a twisted superfluid phase is found which is induced by a spontaneous breaking of the time-reversal symmetry. Using the density-matrix renormalization group allows us to show that the excitation energy gap closes exponentially ... More
Ferromagnetism and non-local correlations in the Hubbard modelMar 08 2012We study the possibility and stability of band-ferromagnetism in the single-band Hubbard model for the simple cubic (SC) lattice. A non-local self-energy is derived within a modified perturbation theory. Results for the spectral density and quasiparticle ... More
Resolvent-Techniques For Multiple Exercise ProblemsSep 27 2013We study optimal multiple stopping of strong Markov processes with random refraction periods. The refraction periods are assumed to be exponentially distributed with a common rate and independent of the underlying dynamics. Our main tool is using the ... More
A host-parasite model for a two-type cell populationApr 02 2012Feb 05 2013A host-parasite model is considered for a population of cells that can be of two types, A or B, and exhibits unilateral reproduction: while a B-cell always splits into two cells of the same type, the two daughter cells of an A-cell can be of any type. ... More
Branching within branching I: The extinction problemMay 15 2015We consider a discrete-time host-parasite model for a population of cells which are colonized by proliferating parasites. The cell population grows like an ordinary Galton-Watson process, but in reflection of real biological settings the multiplication ... More
Lattice point inequalities for centered convex bodiesMay 24 2015We study upper bounds on the number of lattice points for convex bodies having their centroid at the origin. For the family of simplices as well as in the planar case we obtain best possible results. For arbitrary convex bodies we provide an upper bound, ... More
Ultracold quantum gases in triangular optical latticesDec 18 2009Over the last years the exciting developments in the field of ultracold atoms confined in optical lattices have led to numerous theoretical proposals devoted to the quantum simulation of problems e.g. known from condensed matter physics. Many of those ... More
Classification error in multiclass discrimination from Markov dataSep 22 2015As a model for an on-line classification setting we consider a stochastic process $(X_{-n},Y_{-n})_{n}$, the present time-point being denoted by 0, with observables $ \ldots,X_{-n},X_{-n+1},\ldots, X_{-1}, X_0$ from which the pattern $Y_0$ is to be inferred. ... More
Classics Illustrated: Limits of SpacetimesJun 17 2014Oct 06 2014We carefully study the $e \rightarrow m$ and $e \rightarrow 0$ limits of the Reissner-Nordstr\"om spacetime using Geroch's definition of limits of spacetimes. This is implemented by embedding the one-parameter family of spacetimes in anti-de Sitter space, ... More
Budget-restricted utility games with ordered strategic decisionsJul 11 2014We introduce the concept of budget games. Players choose a set of tasks and each task has a certain demand on every resource in the game. Each resource has a budget. If the budget is not enough to satisfy the sum of all demands, it has to be shared between ... More
Azimuthal anisotropies in p+Pb collisions from classical Yang-Mills dynamicsFeb 04 2015May 27 2015We compute single and double inclusive gluon distributions in classical Yang-Mills simulations of proton-lead collisions and extract the associated transverse momentum dependent Fourier harmonics $v_2(p_T)$ and $v_3(p_T)$. Gluons have a large $v_2$ in ... More
Trinification, the Hierarchy Problem and Inverse Seesaw Neutrino MassesDec 18 2010Apr 20 2011In minimal trinification models light neutrino masses can be generated via a radiative see-saw mechanism, where the masses of the right-handed neutrinos originate from loops involving Higgs and fermion fields at the unification scale. This mechanism is ... More
Large-Amplitude Superexchange of High-Spin Fermions in Optical LatticesJun 06 2013Sep 10 2014We show that fermionic high-spin systems with spin-changing collisions allow to monitor superexchange processes in optical superlattices with large amplitudes and strong spin fluctuations. By investigating the non-equilibrium dynamics, we find a superexchange ... 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
Excitation spectrum of Mott shells in optical latticesJun 29 2009We theoretically study the excitation spectrum of confined macroscopic optical lattices in the Mott-insulating limit. For large systems, a fast numerical method is proposed to calculate the ground state filling and excitation energies. We introduce many-particle ... More
Chiral magnetic effect and anomalous transport from real-time lattice simulationsJun 01 2016Sep 26 2016We present a first-principle study of anomaly induced transport phenomena by performing real-time lattice simulations with dynamical fermions coupled simultaneously to non-Abelian $SU(N_c)$ and Abelian $U(1)$ gauge fields. Investigating the behavior of ... More
Results on Charmonium and Charmonium-like States at the Belle ExperimentSep 08 2011New results of the Belle experiment at the KEKB asymmetric e^+e^- collider are presented, in particular (a) measurement of the mass and width of the $\eta_c$ and $\eta_c'$ in B meson decays, (b) measurement of the mass, width and quantum numbers of the ... More
Results on Charmonium(-like) and Bottomonium(-like) States from Belle and BaBarOct 12 2010Spectroscopy results for Belle and BaBar are reported. A particular focus is put on new results of the X(3872) state with its radiative decays to $J$/$\psi$$\gamma$ and $\psi'$$\gamma$, its decay into $J$/$\psi$3$\pi$ and the search for production in ... More
Optimal multiple stopping with random waiting timesMay 09 2012In the standard models for optimal multiple stopping problems it is assumed that between two exercises there is always a time period of deterministic length $\delta$, the so called refraction period. This prevents the optimal exercise times from bunching ... More
Optimal stopping of strong Markov processesMar 21 2012Apr 02 2012We characterize the value function and the optimal stopping time for a large class of optimal stopping problems where the underlying process to be stopped is a fairly general Markov process. The main result is inspired by recent findings for L\'evy processes ... More
Emulating Molecular Orbitals and Electronic Dynamics with Ultracold AtomsMar 20 2015Nov 23 2015In recent years, ultracold atoms in optical lattices have proven their great value as quantum simulators for studying strongly correlated phases and complex phenomena in solid-state systems. Here we reveal their potential as quantum simulators for molecular ... More
Nonlinear amplification of instabilities with longitudinal expansionJan 17 2012We study the dynamics of nonequilibrium instabilities in anisotropically expanding systems. The most prominent example of such a system is the 'Glasma' in the context of relativistic heavy-ion collision experiments, where the expansion is a consequence ... More
Wind Turbine Model and Observer in Takagi-Sugeno Model StructureJan 31 2014Based on a reduced-order, dynamic nonlinear wind turbine model in Takagi-Sugeno (TS) model structure, a TS state observer is designed as a disturbance observer to estimate the unknown effective wind speed. The TS observer model is an exact representation ... More
Optimal portfolio selection under vanishing fixed transaction costsNov 04 2016In this paper, asymptotic results in a long-term growth rate portfolio optimization model under both fixed and proportional transaction costs are obtained. More precisely, the convergence of the model when the fixed costs tend to zero is investigated. ... More
Luzzu Quality Metric Language -- A DSL for Linked Data Quality AssessmentApr 29 2015The steadily growing number of linked open datasets brought about a number of reservations amongst data consumers with regard to the datasets' quality. Quality assessment requires significant effort and consideration, including the definition of data ... More
Hypergeometric analytic continuation of the strong-coupling perturbation series for the 2d Bose-Hubbard modelMar 13 2015Aug 04 2015We develop a scheme for analytic continuation of the strong-coupling perturbation series of the pure Bose-Hubbard model beyond the Mott insulator-to-superfluid transition at zero temperature, based on hypergeometric functions and their generalizations. ... More
Bogoliubov corrections and trace norm convergence for the Hartree dynamicsSep 20 2016We consider the dynamics of a large number N of nonrelativistic bosons in the mean field limit for a class of interaction potentials that includes Coulomb interaction. In order to describe the fluctuations around the mean field Hartree state, we introduce ... More
Improved Bounds and Schemes for the Declustering ProblemMar 02 2006The declustering problem is to allocate given data on parallel working storage devices in such a manner that typical requests find their data evenly distributed on the devices. Using deep results from discrepancy theory, we improve previous work of several ... More
Representing Dataset Quality Metadata using Multi-Dimensional ViewsAug 11 2014Data quality is commonly defined as fitness for use. The problem of identifying quality of data is faced by many data consumers. Data publishers often do not have the means to identify quality problems in their data. To make the task for both stakeholders ... More
Remarks on Kneip's linear smoothersMay 07 2014We were trying to understand the analysis provided by Kneip (1994, Ordered Linear Smoothers). In particular we wanted to persuade ourselves that his results imply the oracle inequality stated by Tsybakov (2014, Lecture 8). This note contains our reworking ... More
Luzzu - A Framework for Linked Data Quality AssessmentDec 11 2014Jan 07 2016With the increasing adoption and growth of the Linked Open Data cloud [9], with RDFa, Microformats and other ways of embedding data into ordinary Web pages, and with initiatives such as, the Web is currently being complemented with a Web of ... More
OpenCourseWare Observatory -- Does the Quality of OpenCourseWare Live up to its Promise?Oct 21 2014Apr 14 2015A vast amount of OpenCourseWare (OCW) is meanwhile being published online to make educational content accessible to larger audiences. The awareness of such courses among users and the popularity of systems providing such courses are increasing. However, ... More
Oscillations and interactions of dark and dark-bright solitons in Bose-Einstein condensatesApr 03 2008Solitons are among the most distinguishing fundamental excitations in a wide range of non-linear systems such as water in narrow channels, high speed optical communication, molecular biology and astrophysics. Stabilized by a balance between spreading ... More
Everything counts! - Warum kleine Gemeinden die Gewinner der Zensuserhebung 2011 sindSep 04 2014The population and housing census 2011 was an EU-wide census in all EU member states. In Germany, the basis was a largely register-based method. In this paper, it is shown that communities with less than 10.000 inhabitants have significantly less relative ... More
Free time evolution of a tracer particle coupled to a Fermi gas in the high-density limitNov 08 2016Nov 24 2016The dynamics of a particle coupled to a dense and homogeneous ideal Fermi gas in two spatial dimensions is studied. We analyze the model for coupling parameter g=1 (i.e., not in the weak coupling regime), and prove closeness of the time evolution to an ... More
A transportable optical lattice clock with $7\times10^{-17}$ uncertaintySep 20 2016We present a transportable optical clock (TOC) with $^{87}$Sr. Its complete characterization against a stationary lattice clock resulted in a systematic uncertainty of ${7.4 \times 10^{-17}}$ which is currently limited by the statistics of the determination ... More
Wikidata through the Eyes of DBpediaJul 15 2015DBpedia is one of the first and most prominent nodes of the Linked Open Data cloud. It provides structured data for more than 100 Wikipedia language editions as well as Wikimedia Commons, has a mature ontology and a stable and thorough Linked Data publishing ... More
Self-Trapping of Bosons and Fermions in Optical LatticesNov 19 2007Aug 01 2008We theoretically investigate the enhanced localization of bosonic atoms by fermionic atoms in three-dimensional optical lattices and find a self-trapping of the bosons for attractive boson-fermion interaction. Because of this mutual interaction, the fermion ... More
Non-equilibrium study of the Chiral Magnetic Effect from real-time simulations with dynamical fermionsDec 07 2016We present a real-time lattice approach to study the non-equilibrium dynamics of vector and axial charges in $SU(N) \times U(1)$ gauge theories. Based on a classical description of the non-Abelian and Abelian gauge fields, we include dynamical fermions ... More
Git4Voc: Git-based Versioning for Collaborative Vocabulary DevelopmentJan 11 2016Collaborative vocabulary development in the context of data integration is the process of finding consensus between the experts of the different systems and domains. The complexity of this process is increased with the number of involved people, the variety ... More
Turbulent thermalization process in high-energy heavy-ion collisionsSep 05 2014We discuss the onset of the thermalization process in high-energy heavy-ion collisions from a weak coupling perspective, using classical-statistical real-time lattice simulations as a first principles tool to study the pre-equilibrium dynamics. Most remarkably, ... More
On Existence and Properties of Approximate Pure Nash Equilibria in Bandwidth Allocation GamesJul 10 2015In \emph{bandwidth allocation games} (BAGs), the strategy of a player consists of various demands on different resources. The player's utility is at most the sum of these demands, provided they are fully satisfied. Every resource has a limited capacity ... More
Co-evolution of RDF DatasetsJan 20 2016Mar 28 2016Linking Data initiatives have fostered the publication of large number of RDF datasets in the Linked Open Data (LOD) cloud, as well as the development of query processing infrastructures to access these data in a federated fashion. However, different ... More
A Semi-Automatic Approach for Detecting Dataset References in Social Science TextsNov 06 2016Today, full-texts of scientific articles are often stored in different locations than the used datasets. Dataset registries aim at a closer integration by making datasets citable but authors typically refer to datasets using inconsistent abbreviations ... More
Quality Assessment of Linked Datasets using Probabilistic ApproximationMar 17 2015With the increasing application of Linked Open Data, assessing the quality of datasets by computing quality metrics becomes an issue of crucial importance. For large and evolving datasets, an exact, deterministic computation of the quality metrics is ... More
Kinetic Energy Estimates for the Accuracy of the Time-Dependent Hartree-Fock Approximation with Coulomb InteractionMar 06 2014Mar 03 2015We study the time evolution of a system of $N$ spinless fermions in $\mathbb{R}^3$ which interact through a pair potential, e.g., the Coulomb potential. We compare the dynamics given by the solution to Schr{\"o}dinger's equation with the time-dependent ... More
Generating massive complex networks with hyperbolic geometry faster in practiceJun 30 2016Generative network models play an important role in algorithm development, scaling studies, network analysis, and realistic system benchmarks for graph data sets. The commonly used graph-based benchmark model R-MAT has some drawbacks concerning realism ... More
Free time evolution of a tracer particle coupled strongly to a Fermi gas in the high-density limitNov 08 2016The dynamics of a distinguished particle coupled to a dense and homogeneous ideal Fermi gas in two spatial dimensions is studied. We analyze the model in a strong coupling regime, i.e., for coupling parameter g of order one, and derive the validity of ... More
New Studies of XYZ States at PANDANov 29 2013Monte Carlo simulations for charmonium(-like) states at the planned PANDA experiment are presented, in particular the search for the $h_c'$, the search for the $^3F_4$ state and the search for the rare decay Y(4260)$\rightarrow$$e^+$$e^-$.
Localization and delocalization of ultracold bosonic atoms in finite optical latticesOct 02 2007Apr 14 2008We study bosonic atoms in small optical lattices by exact diagonalization and observe a striking similarity to the superfluid to Mott insulator transition in macroscopic systems. The momentum distribution, the formation of an energy gap, and the pair ... More
On optimal stopping of multidimensional diffusionsNov 03 2016This paper develops an approach for solving perpetual discounted optimal stopping problems for multidimensional diffusions, with special emphasis on the $d$-dimensional Wiener process. We first obtain some verification theorems for diffusions, based on ... More
Multilevel weighted least squares polynomial approximationJun 30 2017Oct 08 2017Weighted least squares polynomial approximation uses random samples to determine projections of functions onto spaces of polynomials. It has been shown that, using an optimal distribution of sample locations, the number of samples required to achieve ... More
Realization of a time-scale with an accurate optical lattice clockNov 12 2015Feb 22 2016Optical clocks are not only powerful tools for prime fundamental research, but are also deemed for the re-definition of the SI base unit second as they now surpass the performance of caesium atomic clocks in both accuracy and stability by more than an ... More
Quantum phase transition to unconventional multi-orbital superfluidity in optical latticesApr 18 2011Orbital physics plays a significant role for a vast number of important phenomena in complex condensed matter systems such as high-T$_c$ superconductivity and unconventional magnetism. In contrast, phenomena in superfluids -- especially in ultracold quantum ... More
Twist in the bias-dependence of spin-torques in magnetic tunnel junctionsApr 15 2016The spin-torque in magnetic tunnel junctions possesses two components that both depend on the applied voltage. Here, we develop a new method for the accurate extraction of this bias-dependence from experiments over large voltage ranges. We study several ... More
Beyond mean-field study of a binary bosonic mixture in a state-dependent honeycomb latticeJul 21 2014We investigate a binary mixture of bosonic atoms loaded into a state-dependent honeycomb lattice. For this system, the emergence of a so-called twisted-superfluid ground state was experimentally observed in [Soltan-Panahi et al., Nat. Phys. 8, 71 (2012)]. ... More
The ONSEN Data Reduction System for the Belle II Pixel DetectorJun 16 2014Jun 19 2015We present an FPGA-based online data reduction system for the pixel detector of the future Belle II experiment. The occupancy of the pixel detector is estimated at 3 %. This corresponds to a data output rate of more than 20 GB/s after zero suppression, ... More
Non-Preemptive Scheduling on Machines with Setup TimesApr 27 2015Consider the problem in which n jobs that are classified into k types are to be scheduled on m identical machines without preemption. A machine requires a proper setup taking s time units before processing jobs of a given type. The objective is to minimize ... More
Cost-efficient Scheduling on Machines from the CloudSep 05 2016We consider a scheduling problem where machines need to be rented from the cloud in order to process jobs. There are two types of machines available which can be rented for machine-type dependent prices and for arbitrary durations. However, a machine-type ... More
Towards a Semantic Administrative Shell for Industry 4.0 ComponentsJan 07 2016Jan 12 2016In the engineering and manufacturing domain, there is currently an atmosphere of departure to a new era of digitized production. In different regions, initiatives in these directions are known under different names, such as industrie du futur in France, ... More
Coherent multi-flavour spin dynamics in a fermionic quantum gasMar 05 2012Microscopic spin interaction processes are fundamental for global static and dynamical magnetic properties of many-body systems. Quantum gases as pure and well isolated systems offer intriguing possibilities to study basic magnetic processes including ... More
"How much?" Is Not Enough - An Analysis of Open Budget InitiativesApr 07 2015A worldwide movement towards the publication of Open Government Data is taking place, and budget data is one of the key elements pushing this trend. Its importance is mostly related to transparency, but publishing budget data, combined with other actions, ... More
Accurate modeling of plasma acceleration with arbitrary order pseudo-spectral particle-in-cell methodsNov 17 2016Particle in Cell (PIC) simulations are a widely used tool for the investigation of both laser- and beam-driven plasma acceleration. It is a known issue that the beam quality can be artificially degraded by numerical Cherenkov radiation (NCR) resulting ... More
Full- & Reduced-Order State-Space Modeling of Wind Turbine Systems with Permanent-Magnet Synchronous GeneratorFeb 02 2018Wind energy is an integral part of nowadays energy supply and one of the fastest growing sources of electricity in the world today. Accurate models for wind energy conversion systems (WECSs) are of key interest for the analysis and control design of present ... More
Non-Clairvoyant Scheduling to Minimize Max Flow Time on a Machine with Setup TimesSep 18 2017Consider a problem in which $n$ jobs that are classified into $k$ types arrive over time at their release times and are to be scheduled on a single machine so as to minimize the maximum flow time. The machine requires a setup taking $s$ time units whenever ... More
Quantum phases in tunable state-dependent hexagonal optical latticesJan 23 2014Oct 22 2014We study the ground-state properties of ultracold bosonic atoms in a state-dependent graphene-like honeycomb optical lattice, where the degeneracy between the two triangular sublattices A and B can be lifted. We discuss the various geometries accessible ... More
Multi-Orbital Quantum Phase DiffusionNov 26 2009The collapses and revivals of a coherent matter wave field of interacting particles can serve as a sensitive interferometric probe of the interactions and the number statistics of the underlying quantum field. Here we show how the ability to observe long ... More
Towards Cleaning-up Open Data Portals: A Metadata Reconciliation ApproachOct 15 2015This paper presents an approach for metadata reconciliation, curation and linking for Open Governamental Data Portals (ODPs). ODPs have been lately the standard solution for governments willing to put their public data available for the society. Portal ... More
Symmetry-broken momentum distributions induced by matter-wave diffraction during time-of-flight expansion of ultracold atomsJan 22 2016We study several effects which lead to symmetry-broken momentum distributions of quantum gases released from optical lattices. In particular, we demonstrate that interaction within the first milliseconds of the time-of-flight expansion can strongly alter ... More
Cost-efficient Scheduling on Machines from the CloudSep 05 2016Dec 21 2016We consider a scheduling problem where machines need to be rented from the cloud in order to process jobs. There are two types of machines available which can be rented for machine-type dependent prices and for arbitrary durations. However, a machine-type ... More
Accurate modeling of plasma acceleration with arbitrary order pseudo-spectral particle-in-cell methodsNov 17 2016Mar 29 2017Particle in Cell (PIC) simulations are a widely used tool for the investigation of both laser- and beam-driven plasma acceleration. It is a known issue that the beam quality can be artificially degraded by numerical Cherenkov radiation (NCR) resulting ... More