Results for "Michael Engel"

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On sets of eigenvalues of matrices with prescribed row sums and prescribed graphDec 10 2013Motivated by a work of Boros, Brualdi, Crama and Hoffman, we consider the sets of (i) possible Perron roots of nonnegative matrices with prescribed row sums and associated graph, and (ii) possible eigenvalues of complex matrices with prescribed associated ... More
The eShel Spectrograph: A Radial-velocity Tool at the Wise ObservatoryMar 29 2017The eShel, an off-the-shelf, fiber-fed echelle spectrograph ($R \approx 10,000$), was installed on the 1m telescope at the Wise observatory in Israel. We report the installation of the multi-order spectrograph, and describe our pipeline to extract stellar ... More
Non-Close-Packed Three-Dimensional QuasicrystalsFeb 28 2017Jun 23 2017Quasicrystals are frequently encountered in condensed matter. They are important candidates for equilibrium phases from the atomic scale to the nanoscale. Here, we investigate the computational self-assembly of four quasicrystals in a single model system ... More
Newton's Inequalities on a LatticeFeb 11 2010Jun 14 2010Functions that satisfy the Hadamard Fisher Inequalities also satisfy Newton's Inequalities
Room-Temperature Quantum-Confined Stark Effect in Atomically Thin SemiconductorFeb 08 2018Electric field-controlled, two-dimensional (2D) exciton dynamics in transition metal dichalcogenide monolayers is a current research focus in condensed matter physics. We have experimentally investigated the spectral and temporal properties of the A-exciton ... More
Efficient Equilibration of Hard Spheres with Newtonian Event ChainsMar 27 2019An important task in the simulation of hard spheres and other hard particles is structure prediction via equilibration. Event-driven molecular dynamics is efficient because its Newtonian dynamics equilibrates fluctuations with the speed of sound. Monte ... More
Complex Crystals from Size-disperse SpheresOct 31 2018Mar 18 2019Colloids are rarely perfectly uniform but follow a distribution of sizes, shapes, and charges. This dispersity can be inherent (static) or develop and change over time (dynamic). Despite a long history of research, the conditions under which non-uniform ... More
Rough index theory on spaces of polynomial growth and contractibilityMay 15 2015Apr 10 2018We will show that for a polynomially contractible manifold of bounded geometry and of polynomial volume growth every coarse and rough cohomology class pairs continuously with the K-theory of the uniform Roe algebra. As an application we will discuss non-vanishing ... More
Wrong way maps in uniformly finite homology and homology of groupsFeb 10 2016Apr 02 2019Given a non-compact Riemannian manifold M and a submanifold N of codimension q, we will construct under certain assumptions on both M and N a wrong way map in uniformly finite homology. Using an equivariant version of the construction and applying it ... More
A Proof of Looijenga's Conjecture via Integral-affine GeometrySep 26 2014A cusp singularity is an elliptic surface singularity whose minimal resolution is a cycle of smooth rational curves meeting transversely. Cusp singularities come in naturally dual pairs. In 1981, Looijenga proved that whenever a cusp singularity is smoothable, ... More
Log-concavity of the overpartition functionDec 15 2014Dec 22 2014We prove that the overpartition function is log-concave for all n>1. The proof is based on Sills Rademacher type series for the overpartition function and inspired by Desalvo and Pak's proof for the partition function.
Wrong way maps in uniformly finite homology and homology of groupsFeb 10 2016Sep 07 2017Given a non-compact Riemannian manifold M and a submanifold N of codimension q, we will construct under certain assumptions on both M and N a wrong way map in uniformly finite homology. Using an equivariant version of the construction and applying it ... More
Indices of pseudodifferential operators on open manifoldsOct 29 2014We generalize Roe's Index Theorem for operators of Dirac type on open manifolds to elliptic pseudodifferential operators. To this end we introduce a class of pseudodifferential operators on manifolds of bounded geometry which is more general than similar ... More
Status and Future of Nuclear Matrix Elements for Neutrinoless Double-Beta Decay: A ReviewOct 20 2016Mar 27 2017The nuclear matrix elements that govern the rate of neutrinoless double beta decay must be accurately calculated if experiments are to reach their full potential. Theorists have been working on the problem for a long time but have recently stepped up ... More
Controlled self-assembly of periodic and aperiodic cluster crystalsJan 17 2014Soft particles are known to overlap and form stable clusters that self-assemble into periodic crystalline phases with density-independent lattice constants. We use molecular dynamics simulations in two dimensions to demonstrate that, through a judicious ... More
Hadronic Multiparticle Production at Ultra-High Energies and Extensive Air ShowersOct 20 2010Studies of the nature of cosmic ray particles at the highest energies are based on the measurement of extensive air showers. Most cosmic ray properties can therefore only be obtained from the interpretation of air shower data and are thus depending on ... More
The Habitable Zone Planet Finder: A Proposed High Resolution NIR Spectrograph for the Hobby Eberly Telescope to Discover Low Mass Exoplanets around M DwarfsJul 19 2010The Habitable Zone Planet Finder (HZPF) is a proposed instrument for the 10m class Hobby Eberly telescope that will be capable of discovering low mass planets around M dwarfs. HZPF will be fiber-fed, provide a spectral resolution R~ 50,000 and cover the ... More
Confirmation of the random tiling hypothesis for a decagonal quasicrystalOct 16 2012Mechanisms that stabilize quasicrystals are much discussed but not finally resolved. We confirm the random tiling hypothesis and its predictions in a fully atomistic decagonal quasicrystal model by calculating the free energy and the phason elastic constants ... More
A black phosphorus photo-detector for multispectral, high-resolution imagingJul 09 2014Jul 30 2014Black phosphorus is a layered semiconductor that is intensely researched in view of applications in optoelectronics. In this Letter, we investigate a multi-layer black phosphorus photo-detector that is capable of acquiring high-contrast (V>0.9) images ... More
Neutralino Inelastic Scattering with Subsequent Detection of Nuclear Gamma RaysOct 19 1999We consider the potential benefits of searching for supersymmetric dark-matter through its inelastic excitation, via the "scalar current", of low-lying collective nuclear states in a detector. If such states live long enough so that the gamma radiation ... More
Finite size analysis of the pseudo specific heat in SU(2) gauge theoryJul 19 1996We investigate the pseudo specific heat of SU(2) gauge theory near the crossover point on $4^4$ to $16^4$ lattices. Several different methods are used to determine the specific heat. The curious finite size dependence of the peak maximum is explained ... More
The number of convex tilings of the sphere by triangles, squares, or hexagonsFeb 08 2017Jan 16 2018A tiling of the sphere by triangles, squares, or hexagons is convex if every vertex has at most 6, 4, or 3 polygons adjacent to it, respectively. Assigning an appropriate weight to any tiling, our main result is explicit formulas for the weighted number ... More
The Muon Anomalous Magnetic Moment and the Pion PolarizabilitySep 09 2013We compute the charged pion loop contribution to the muon anomalous magnetic moment $a_\mu$, taking into account the effect of the charged pion polarizability, $(\alpha_1-\beta_1)_{\pi^+}$. We evaluate this contribution using two different models that ... More
Numerical approximation of a coagulation-Fragmentation Model for Animal Group Size StatisticsApr 21 2016Jul 02 2016We study numerically a coagulation-fragmentation model derived by Niwa and further elaborated by Degond et al., where a unique equilibrium distribution of group sizes is shown to exist in both cases of continuous and discrete group size distributions. ... More
Preliminary Investigation of a Waveform Analysis with the WASA and the ACQIRIS Readout ElectronicsJun 28 2013Jul 16 2013The Group for the development of neutron and gamma detectors in the Central Institute of Engineering, Electronics and Analytics (ZEA-2) at Forschungszentrum J\"ulich (FZJ) is developing a fast Anger Camera prototype for improving the rejection of the ... More
Finite size dependence of scaling functions of the three-dimensional O(4) model in an external fieldFeb 21 2014Jun 13 2014We calculate universal finite size scaling functions for the order parameter and the longitudinal susceptibility of the three-dimensional O(4) model. The phase transition of this model is supposed to be in the same universality class as the chiral transition ... More
Longitudinal and transverse spectral functions in the three-dimensional O(4) modelNov 10 2009We have performed a high statistics simulation of the O(4) model on a three-dimensional lattice of linear extension L=120 for small external fields H. Using the maximum entropy method we analyze the longitudinal and transverse plane spin correlation functions ... More
Corrections to Scaling and Critical Amplitudes in SU(2) Lattice Gauge TheoryAug 27 1998We calculate the critical amplitudes of the Polyakov loop and its susceptibility at the deconfinement transition of SU(2) gauge theory. To this end we carefully study the corrections to the scaling functions of the observables coming from irrelevant exponents. ... More
Simulation studies for the MADMAX axion direct detection experimentNov 01 2018We present a general approach to solve the Maxwell-axion equations for arbitrary geometries and materials. The approach is based on the finite element method (FEM) and applied to experimental setups related to the new MADMAX (MAgnetized Disc and Mirror ... More
Spectral theory for structured perturbations of linear operatorsJun 16 2016We characterize the spectrum (and its parts) of operators which can be represented as G=A+BC for a simpler operator A and a structured perturbation BC. The interest in this kind of perturbations is motivated, e.g., by perturbations of the domain of an ... More
Octupole correlations in low-lying states of 150Nd and 150Sm and their impact on neutrinoless double-beta decayApr 21 2016Jul 07 2016We present a generator-coordinate calculation, based on a relativistic energy-density functional, of the low-lying spectra in the isotopes $^{150}$Nd and $^{150}$Sm and of the nuclear matrix element that governs the neutrinoless double-beta decay of the ... More
Operators with Wentzell boundary conditions and the Dirichlet-to-Neumann operatorJan 16 2018Nov 27 2018In this paper we relate the generator property of an operator $A$ with (abstract) generalized Wentzell boundary conditions on a Banach space $X$ and its associated (abstract) Dirichlet-to-Neumann operator $N$ acting on a "boundary" space $\partial X$. ... More
Boundary optimization for rough setsSep 15 2017Let $n > m\ge 2$ be integers and let $\mathcal{A}=\{A_1,\dots,A_m\}$ be a partition of $[n]=\{1,\dots,n\}$. For $X \subseteq [n]$, its $\mathcal{A}$-boundary region $\mathcal{A}(X)$ is defined to be the union of those blocks $A_i$ of $\mathcal{A}$ for ... More
On the measurement of the proton-air cross section using longitudinal shower profilesDec 08 2006In this paper, we will discuss the prospects of deducing the proton-air cross section from fluorescence telescope measurements of extensive air showers. As it is not possible to observe the point of first interaction $X_{\rm 1}$ directly, other observables ... More
On the measurement of the proton-air cross section using air shower dataMar 02 2009May 14 2009The analysis of high-energy air shower data allows one to study the proton-air cross section at energies beyond the reach of fixed target and collider experiments. The mean depth of the first interaction point and its fluctuations are a measure of the ... More
On the measurement of the proton-air cross section using cosmic ray dataSep 10 2007Cosmic ray data may allow the determination of the proton-air cross section at ultra-high energy. For example, the distribution of the first interaction point in air showers reflects the particle production cross section. As it is not possible to observe ... More
Hadronic Light-by-Light and the Pion PolarizabilityJan 04 2012Jan 13 2012We compute the charged pion loop contribution to the light-by-light scattering amplitude for off-shell photons in chiral perturbation theory through next-to-leading order (NLO). We show that NLO contributions are relatively more important due to a fortuitous ... More
Power dissipation and electrical breakdown in black phosphorusJul 02 2015We report operating temperatures and heating coefficients measured in a multi-layer black phosphorus device as a function of injected electrical power. By combining micro-Raman spectroscopy and electrical transport measurements, we have observed a linear ... More
Origin of photoresponse in black phosphorus photo-transistorsJul 27 2014We study the origin of photocurrent generated in doped multilayer BP photo-transistors, and find that it is dominated by thermally driven thermoelectric and bolometric processes. The experimentally observed photocurrent polarities are consistent with ... More
Proton-Air Cross Section and Extensive Air ShowersJun 17 2009Hadronic cross sections at ultra-high energy have a significant impact on the development of extensive air shower cascades. Therefore the interpretation of air shower data depends critically on hadronic interaction models that extrapolate the cross section ... More
Open Questions in Cosmic-Ray Research at Ultrahigh EnergiesMar 15 2019We review open questions and prospects for progress in ultrahigh-energy cosmic ray (UHECR) research, based on a series of discussions that took place during the `The High-Energy Universe: Gamma-Ray, Neutrino, and Cosmic-ray Astronomy' MIAPP workshop in ... More
Dynamics of particle flips in two-dimensional quasicrystalsJun 09 2010Oct 08 2010The dynamics of quasicrystals is more complicated than the dynamics of periodic solids and difficult to study in experiments. Here, we investigate a decagonal and a dodecagonal quasicrystal using molecular dynamics simulations of the Lennard-Jones-Gauss ... More
Electric Dipole Moments of Nucleons, Nuclei, and Atoms: The Standard Model and BeyondMar 10 2013Searches for the permanent electric dipole moments (EDMs) of molecules, atoms, nucleons and nuclei provide powerful probes of CP violation both within and beyond the Standard Model (BSM). The interpretation of experimental EDM limits requires careful ... More
Phason Dynamics in One-Dimensional LatticesFeb 09 2010In quasicrystals, the phason degree of freedom and the inherent anharmonic potentials lead to complex dynamics which cannot be described by the usual phonon modes of motion. We have constructed simple one-dimensional model systems, the dynamic Fibonacci ... More
Anomalous Longitudinal Shower Profiles and Hadronic InteractionsNov 02 2011The bulk of air showers initiated by very high energy cosmic rays exhibits a longitudinal development in depth with a single well-defined shower maximum. However, a small fraction of showers has a profile that differs considerably from this average behaviour. ... More
Magnetically-defined topological edge plasmons in edgeless electron gasMar 07 2018Topological materials bear gapped excitations in bulk yet protected gapless excitations at boundaries. Magnetoplasmons (MPs), as high-frequency density excitations of two-dimensional electron gas (2DEG) in a perpendicular magnetic field, embody a prototype ... More
Dense crystalline dimer packings of regular tetrahedraJan 05 2010Jul 25 2010We present the densest known packing of regular tetrahedra with density phi = 4000/4671 = 0.856347... Like the recently discovered packings of Kallus et al. [arXiv:0910.5226] and Torquato-Jiao [arXiv:0912.4210], our packing is crystalline with a unit ... More
The Dilworth Number of Auto-Chordal-Bipartite GraphsSep 23 2013The mirror (or bipartite complement) mir(B) of a bipartite graph B=(X,Y,E) has the same color classes X and Y as B, and two vertices x in X and y in Y are adjacent in mir(B) if and only if xy is not in E. A bipartite graph is chordal bipartite if none ... More
Observation of Faraday Waves in a Bose-Einstein CondensateJan 01 2007Faraday waves in a cigar-shaped Bose-Einstein condensate are created. It is shown that periodically modulating the transverse confinement, and thus the nonlinear interactions in the BEC, excites small amplitude longitudinal oscillations through a parametric ... More
Learning Multiscale Features Directly From WaveformsMar 31 2016Apr 05 2016Deep learning has dramatically improved the performance of speech recognition systems through learning hierarchies of features optimized for the task at hand. However, true end-to-end learning, where features are learned directly from waveforms, has only ... More
Influence of surface tension on the conical miniscus of a magnetic fluid in the field of a current-carrying wireMar 06 2006We study the influence of surface tension on the shape of the conical miniscus built up by a magnetic fluid surrounding a current-carrying wire. Minimization of the total energy of the system leads to a singular second order boundary value problem for ... More
External field dependence of the correlation lengths in the three-dimensional O(4) modelSep 01 2003We investigate numerically the transverse and longitudinal correlation lengths of the three-dimensional O(4) model as a function of the external field H. In the low-temperature phase we verify explicitly the H^{-1/2}-dependence of the transverse correlation ... More
Scaling Properties of the Energy Density in SU(2) Lattice Gauge TheoryAug 08 1994The lattice data for the energy density of $SU(2)$ gauge theory are calculated with \nop~derivatives of the coupling constants. These derivatives are obtained from two sources : i) a parametrization of the \nop~beta function in accord with the measured ... More
Techno-Economic Analysis and Optimal Control of Battery Storage for Frequency Control Services, Applied to the German MarketMar 11 2019Optimal investment in battery energy storage systems, taking into account degradation, sizing and control, is crucial for the deployment of battery storage, of which providing frequency control is one of the major applications. In this paper, we present ... More
Chiral Two-Body Currents and Neutrinoless Double-Beta Decay in the QRPAMar 31 2014We test the effects of an approximate treatment of two-body contributions to the axial-vector current on the QRPA matrix elements for neutrinoless double-beta decay in a range of isotopes. The form and strength of the two-body terms come from chiral effective-field ... More
Correlation lengths and scaling functions in the three-dimensional O(4) modelJul 31 2003Oct 20 2003We investigate numerically the transverse and longitudinal correlation lengths of the three-dimensional O(4) model as a function of the external field H. From our data we calculate the scaling function of the transverse correlation length, and that of ... More
Determination of Anisotropy Coefficients for SU(3) Gauge Actions from the Integral and Matching MethodsMay 03 1999We use two non-perturbative methods to obtain the anisotropy derivatives of the coupling constants (the anisotropy coefficients) of SU(3) lattice gauge theory. These coefficients appear in the derivative formulae for the energy density and the pressure. ... More
Direct determination of the gauge coupling derivatives for the energy density in lattice QCDSep 05 1997By matching Wilson loop ratios on anisotropic lattices we measure the coefficients $\cs$ and $\ct$, which are required for the calculation of the energy density. The results are compared to that of an indirect method of determination. We find similar ... More
Scaling and Goldstone effects in a QCD with two flavours of adjoint quarksMay 11 2005We study QCD with two Dirac fermions in the adjoint representation at finite temperature by Monte Carlo simulations.In such a theory the deconfinement and chiral phase transitions occur at different temperatures. We locate the second order chiral transition ... More
Accessing dark states optically through excitation-ferrying statesMar 24 2017Sep 05 2017The efficiency of solar energy harvesting systems is largely determined by their ability to transfer excitations from the antenna to the energy trapping center before recombination. Dark state protection, achieved by coherent coupling between subunits ... More
Discretized Fast-Slow Systems near Pitchfork SingularitiesFeb 18 2019Motivated by the normal form of a fast-slow ordinary differential equation exhibiting a pitchfork singularity we consider the discrete-time dynamical system that is obtained by an application of the explicit Euler method. Tracking trajectories in the ... More
Shaping wave patterns in reaction-diffusion systemsMay 16 2014Dec 12 2014We present a method to control the two-dimensional shape of traveling wave solutions to reaction-diffusion systems, as e.g. interfaces and excitation pulses. Control signals that realize a pre-given wave shape are determined analytically from nonlinear ... More
High-quality dry transferred CVD bilayer grapheneApr 14 2017We report on the fabrication and characterization of high-quality chemical vapor-deposited (CVD) bilayer graphene (BLG). In particular, we demonstrate that CVD-grown BLG can mechanically be detached from the copper foil by an hexagonal boron nitride (hBN) ... More
Emergent collective phenomena in a mixture of hard shapes through active rotationAug 09 2013We investigate collective phenomena with rotationally driven spinners of concave shape. Each spinner experiences a constant internal torque in either a clockwise or counterclockwise direction. Although the spinners are modeled as hard, otherwise non-interacting ... More
A metric for wettability at the nanoscaleAug 29 2016Wettability is the affinity of a liquid for a solid surface. For energetic reasons, macroscopic drops of liquid are nearly spherical away from interfaces with solids, and any local deformations due to molecular-scale surface interactions are negligible. ... More
Complexity in surfaces of densest packings for families of polyhedraSep 10 2013Packings of hard polyhedra have been studied for centuries due to their mathematical aesthetic and more recently for their applications in fields such as nanoscience, granular and colloidal matter, and biology. In all these fields, particle shape is important ... More
Probability of the resistive state formation caused by absorption of a single-photon in current-carrying superconducting nano-stripsOct 25 2004We have studied supercurrent-assisted formation of the resistive state in nano-structured Nb and NbN superconducting films after absorption of a single photon. In amorphous narrow NbN strips the probability of the resistive state formation has a pronounced ... More
Controlling Chirality of Entropic CrystalsJul 14 2015Colloidal crystal structures with complexity and diversity rivaling atomic and molecular crystals have been predicted and obtained for hard particles by entropy maximization. However, so far homochiral colloidal crystals, which are candidates for photonic ... More
High mobility dry-transferred CVD bilayer grapheneApr 14 2017May 08 2018We report on the fabrication and characterization of high-quality chemical vapor-deposited (CVD) bilayer graphene (BLG). In particular, we demonstrate that CVD-grown BLG can mechanically be detached from the copper foil by an hexagonal boron nitride (hBN) ... More
Understanding shape entropy through local dense packingSep 04 2013Oct 28 2014Entropy drives the phase behavior of colloids ranging from dense suspensions of hard spheres or rods to dilute suspensions of hard spheres and depletants. Entropic ordering of anisotropic shapes into complex crystals, liquid crystals, and even quasicrystals ... More
Entropically Patchy Particles: Engineering Valence through Shape EntropyApr 29 2013Feb 13 2014Patchy particles are a popular paradigm for the design and synthesis of nanoparticles and colloids for self-assembly. In "traditional" patchy particles, anisotropic interactions arising from patterned coatings, functionalized molecules, DNA, and other ... More
Ballistic transport exceeding 28 μm in CVD grown grapheneNov 27 2015Jan 12 2016We report on ballistic transport over more than 28 \mu m in graphene grown by chemical vapor deposition (CVD) that is fully encapsulated in hexagonal boron nitride. The structures are fabricated by an advanced dry van-der-Waals transfer method and exhibit ... More
Complex Crystals from Size-disperse SpheresOct 31 2018Nov 02 2018Colloids are rarely uniform but follow a distribution of sizes, shapes, and charges. This dispersity can be inherent (static) or develop and change over time (dynamic). Despite a long history of research, the conditions under which non-uniform particles ... More
Light-matter interaction in a microcavity-controlled graphene transistorDec 06 2011Jun 25 2012Graphene has extraordinary electronic and optical properties and holds great promise for applications in photonics and optoelectronics. Demonstrations including high-speed photodetectors, optical modulators, plasmonic devices, and ultrafast lasers have ... More
Shape and symmetry determine two-dimensional melting transitions of hard regular polygonsJun 02 2016Dec 23 2016The melting transition of two-dimensional (2D) systems is a fundamental problem in condensed matter and statistical physics that has advanced significantly through the application of computational resources and algorithms. 2D systems present the opportunity ... More
An ultra-fast superconducting Nb nanowire single-photon detector for soft X-raysAug 08 2012Sep 12 2012Although superconducting nanowire single-photon detectors (SNSPDs) are well studied regarding the detection of infrared/optical photons and keV-molecules, no studies on continuous X-ray photon counting by thick-film detectors have been reported so far. ... More
Fluid-to-solid transition of hard regular polygonsJun 02 2016Characterizing the fluid-to-solid transition (conversely the melting transition) of two-dimensional systems is a fundamental problem in condensed matter physics that has advanced significantly through the application of computational resources and algorithms. ... More
Massively parallel Monte Carlo for many-particle simulations on GPUsNov 07 2012Aug 23 2013Current trends in parallel processors call for the design of efficient massively parallel algorithms for scientific computing. Parallel algorithms for Monte Carlo simulations of thermodynamic ensembles of particles have received little attention because ... More
Hard-disk equation of state: First-order liquid-hexatic transition in two dimensions with three simulation methodsNov 07 2012Apr 24 2013We report large-scale computer simulations of the hard-disk system at high densities in the region of the melting transition. Our simulations reproduce the equation of state, previously obtained using the event-chain Monte Carlo algorithm, with a massively ... More
Low-temperature structure of xi'-Al-Pd-Mn optimized by ab-initio methodsSep 08 2011Oct 27 2011We have studied and resolved occupancy correlations in the existing average structure model of the complex metallic alloy xi'-Al-Pd-Mn [Boudard et al., Phil. Mag. A, 74, 939 (1996)], which has approximately 320 atoms in the unit cell and many fractionally ... More
Packing and Self-assembly of Truncated Triangular BipyramidsApr 10 2013Aug 14 2013Motivated by breakthroughs in the synthesis of faceted nano- and colloidal particles, as well as theoretical and computational studies of their packings, we investigate a family of truncated triangular bipyramids. We report dense periodic packings with ... More
Sensitivity of Extensive Air Showers to Features of Hadronic Interactions at Ultra-High EnergiesJun 02 2009We study the dependence of extensive air shower development on the first hadronic interactions at ultra-high energies occurring in the startup phase of the air shower cascade. The interpretation of standard air shower observables depends on the characteristics ... More
AGB and post-AGB starsAug 12 2005Intermediate mass stars (1-8 solar masses) evolve along the Asymptotic Giant Branch after completion of hydrogen and helium core burning. At the tip they lose for several ten to hundred thousand years copious amounts of mass and exhibit various forms ... More
Intrinsic-Density FunctionalsOct 10 2006The Hohenberg-Kohn theorem and Kohn-Sham procedure are extended to functionals of the localized intrinsic density of a self-bound system such as a nucleus. After defining the intrinsic-density functional, we modify the usual Kohn-Sham procedure slightly ... More
Wrong way maps in uniformly finite homology and homology of groupsFeb 10 2016Dec 01 2016Given a non-compact Riemannian manifold M and a submanifold N of codimension q, we will construct under certain assumptions on both M and N a wrong way map in uniformly finite homology. Using an equivariant version of the construction and applying it ... More
Rough index theory on spaces of polynomial growth and contractibilityMay 15 2015Jul 24 2015We will show for a polynomially contractible manifold M of bounded geometry and of polynomial volume growth that every coarse cohomology class of M pairs continuously against the K-theory of the uniform Roe algebra of M. From this we will conclude that ... More
Banach strong Novikov conjecture for polynomially contractible groupsFeb 08 2017Apr 10 2018We prove the Banach strong Novikov conjecture for groups having polynomially bounded higher-order combinatorial functions. This includes all automatic groups.
Bifurcation Analysis of a Stochastically Driven Limit CycleJun 03 2016Feb 14 2018We establish the existence of a bifurcation from an attractive random equilibrium to shear-induced chaos for a stochastically driven limit cycle, indicated by a change of sign of the first Lyapunov exponent. This addresses an open problem posed by Kevin ... More
Conditioned Lyapunov exponents for random dynamical systemsMay 18 2018We introduce the notion of Lyapunov exponents for random dynamical systems, conditioned to trajectories that stay within a bounded domain for asymptotically long times. This is motivated by the desire to characterize local dynamical properties in the ... More
Quantum-Hall plateau-plateau transition in top-gated epitaxial graphene grown on SiC (0001)Dec 19 2011Dec 20 2011We investigate the low-temperature magneto-transport properties of monolayer epitaxial graphene films formed on the Si-face of semi-insulating 4H-SiC substrates by a high temperature sublimation process. A high-k top-gate on the epitaxial graphene is ... More
Universality of electron distributions in high-energy air showers - description of Cherenkov light productionJun 29 2005Dec 22 2005The shower simulation code CORSIKA has been used to investigate the electron energy and angular distributions in high-energy showers. Based on the universality of both distributions, we develop an analytical description of Cherenkov light emission in ... More
Replica mean-field theory for Levy spin-glassesJan 10 2007Infinite-range spin-glass models with Levy-distributed interactions show a freezing transition similar to disordered spin systems on finite connectivity random graphs. It is shown that despite diverging moments of the local field distribution this transition ... More
Nuclear Matrix Elements for Double-Beta DecayOct 31 2015Recent progress in nuclear-structure theory has been dramatic. I describe recent and future applications of ab initio calculations and the generator coordinate method to double-beta decay. I also briefly discuss the old and vexing problem of the renormalization ... More
Deep Object Tracking on Dynamic Occupancy Grid Maps Using RNNsMay 23 2018The comprehensive representation and understanding of the driving environment is crucial to improve the safety and reliability of autonomous vehicles. In this paper, we present a new approach to establish an environment model containing a segmentation ... More
Anomalous Behavior of 2+ Excitations around 132SnAug 21 2002Oct 04 2002In certain neutron-rich Te isotopes, a decrease in the energy of the first excited 2+ state is accompanied by a decrease in the E2 strength to that state from the ground state, contradicting simple systematics and general intuition about quadrupole collectivity. ... More
Formation of Quantum Shock Waves by Merging and Splitting Bose-Einstein CondensatesMar 18 2008The processes of merging and splitting dilute-gas Bose-Einstein condensates are studied in the nonadiabatic, high-density regime. Rich dynamics are found. Depending on the experimental parameters, uniform soliton trains containing more than ten solitons ... More
Localizing to submanifolds in uniformly finite homologyFeb 10 2016Given a non-compact Riemannian manifold M and a submanifold N of codimension q, we will construct under certain assumptions on both M and N a localization map in uniformly finite homology. Investigating the continuity of the localization map for certain ... More
Comment on "Invalidation of the Kelvin Force in Ferrofluids"Jan 24 2001It is shown that the experimental results reported in cond-mat/0010412 do not invalidate the well-known expression for the Kelvin force density in ferrofluids.
Correlation of internal representations in feed-forward neural networksApr 11 1996Feed-forward multilayer neural networks implementing random input-output mappings develop characteristic correlations between the activity of their hidden nodes which are important for the understanding of the storage and generalization performance of ... More
Approximate Treatment of Lepton Distortion in Charged-Current Neutrino Scattering from NucleiNov 21 1997The partial-wave expansion used to treat the distortion of scattered electrons by the nuclear Coulomb field is simpler and considerably less time-consuming when applied to the production of muons and electrons by low and intermediate-energy neutrinos. ... More