Results for "Stefan Schuster"

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The combinatorial multitude of fatty acids can be described by Fibonacci numbersMar 28 2013The famous series of Fibonacci numbers is defined by a recursive equation saying that each number is the sum of its two predecessors, with the initial condition that the first two numbers are equal to unity. Here, we show that the numbers of fatty acids ... More
Hierarchical Crossover and Probability Landscapes of Genetic OperatorsApr 28 1995The time evolution of a simple model for crossover is discussed. A variant of this model with an improved exploration behavior in phase space is derived as a subset of standard one- and multi-point crossover operations. This model is solved analytically ... More
A kernel-based approach to molecular conformation analysisSep 28 2018Dec 04 2018We present a novel machine learning approach to understanding conformation dynamics of biomolecules. The approach combines kernel-based techniques that are popular in the machine learning community with transfer operator theory for analyzing dynamical ... More
Optimizing defence, counter-defence and counter-counter defence in parasitic and trophic interactions -- A modelling studyJul 10 2019In host-pathogen interactions, often the host (attacked organism) defends itself by some toxic compound and the parasite, in turn, responds by producing an enzyme that inactivates that compound. In some cases, the host can respond by producing an inhibitor ... More
Inter-Coder Agreement for Nominal Scales: A Model-based ApproachAug 06 2012Inter-coder agreement measures, like Cohen's kappa, correct the relative frequency of agreement between coders to account for agreement which simply occurs by chance. However, in some situations these measures exhibit behavior which make their values ... More
Beyond Hebb: Exclusive-OR and Biological LearningSep 15 1999Mar 24 2000A learning algorithm for multilayer neural networks based on biologically plausible mechanisms is studied. Motivated by findings in experimental neurobiology, we consider synaptic averaging in the induction of plasticity changes, which happen on a slower ... More
Analyzing high-dimensional time-series data using kernel transfer operator eigenfunctionsMay 16 2018Kernel transfer operators, which can be regarded as approximations of transfer operators such as the Perron-Frobenius or Koopman operator in reproducing kernel Hilbert spaces, are defined in terms of covariance and cross-covariance operators and have ... More
Eigendecompositions of Transfer Operators in Reproducing Kernel Hilbert SpacesDec 05 2017May 16 2018Transfer operators such as the Perron--Frobenius or Koopman operator play an important role in the global analysis of complex dynamical systems. The eigenfunctions of these operators can be used to detect metastable sets, to project the dynamics onto ... More
Convolutions and multiplier transformations of convex bodiesJul 31 2012Rotation intertwining maps from the set of convex bodies in Rn into itself that are continuous linear operators with respect to Minkowski and Blaschke addition are investigated. The main focus is on Blaschke-Minkowski homomorphisms. We show that such ... More
Crofton measures and Minkowski valuationsJul 31 2012A description of continuous rigid motion compatible Minkowski valuations is established. As an application, we present a Brunn-Minkowski type inequality for intrinsic volumes of these valuations.
Singular Value Decomposition of Operators on Reproducing Kernel Hilbert SpacesJul 24 2018Reproducing kernel Hilbert spaces (RKHSs) play an important role in many statistics and machine learning applications ranging from support vector machines to Gaussian processes and kernel embeddings of distributions. Operators acting on such spaces are, ... More
Kernel Conditional Density OperatorsMay 27 2019We introduce a conditional density estimation model termed the conditional density operator. It naturally captures multivariate, multimodal output densities and is competitive with recent neural conditional density models and Gaussian processes. To derive ... More
Minkowski Valuations and Generalized ValuationsJul 20 2015A convolution representation of continuous translation invariant and SO(n) equivariant Minkowski valuations is established. This is based on a new classification of translation invariant generalized spherical valuations. As applications, Crofton and kinematic ... More
Binary Operations in Spherical Convex GeometryJul 04 2014Characterizations of binary operations between convex bodies on the Euclidean unit sphere are established. The main result shows that the convex hull is essentially the only non-trivial projection covariant operation between pairs of convex bodies contained ... More
Rotation invariant Minkowski classes of convex bodiesJul 31 2012A Minkowski class is a closed subset of the space of convex bodies in Euclidean space Rn which is closed under Minkowski addition and non-negative dilatations. A convex body in Rn is universal if the expansion of its support function in spherical harmonics ... More
Volume inequalities for asymmetric Wulff shapesOct 10 2011Oct 12 2011Sharp reverse affine isoperimetric inequalities for asymmetric Wulff shapes and their polars are established, along with the characterization of all extremals. These new inequalities have as special cases previously obtained simplex inequalities by Ball, ... More
On the GL(V)-module structure of K(n)^*(BV)Nov 30 2007We study the question of whether the Morava K-theory of the classifying space of an elementary abelian group V is a permutation module (in either of two distinct senses) for the automorphism group of V. We use Brauer characters and computer calculations. ... More
The Sine Transform of Isotropic MeasuresJul 31 2012Sharp isoperimetric inequalities for the sine transform of even isotropic measures are established. The corresponding reverse inequalities are obtained in an asymptotically optimal form. These new inequalities have direct applications to strong volume ... More
The Steiner Formula for Minkowski ValuationsJul 31 2012A Steiner type formula for continuous translation invariant Minkowski valuations is established. In combination with a recent result on the symmetry of rigid motion invariant homogeneous bivaluations, this new Steiner type formula is used to obtain a ... More
GL(n) contravariant Minkowski valuationsJul 31 2012A complete classification of all continuous GL(n) contravariant Minkowski valuations is established. As an application we present a family of sharp isoperimetric inequalities for such valuations which generalize the classical Petty projection inequality. ... More
General Lp affine isoperimetric inequalitiesSep 11 2008Sharp Lp affine isoperimetric inequalities are established for the entire class of Lp projection bodies and the entire class of Lp centroid bodies. These new inequalities strengthen the Lp Petty projection and the Lp Busemann--Petty centroid inequality. ... More
A modified algebraic reconstruction technique taking refraction into account with an application in terahertz tomographyJan 18 2016Terahertz (THz) tomography is a rather novel technique for nondestructive testing that is particularly suited for the testing of plastics and ceramics. Previous publications showed a large variety of conventional algorithms adapted from computed tomography ... More
DFT investigations of the piezoresistive effect of carbon nanotubes for sensor applicationJun 29 2017We investigate the piezoresistive effect of carbon nanotubes (CNTs) within density functional theory (DFT) aiming at application-relevant CNTs. CNTs are excellent candidates for the usage in nano-electromechanical sensors (NEMS) due to their small band ... More
An improved exact inversion formula for cone beam vector tomographyMar 09 2016In this article we present an improved exact inversion formula for the 3D cone beam transform of vector fields. It is well known that only the solenoidal part of a vector field can be determined by the longitudinal ray transform of a vector field in cone ... More
Automated Detection, Exploitation, and Elimination of Double-Fetch Bugs using Modern CPU FeaturesNov 03 2017Double-fetch bugs are a special type of race condition, where an unprivileged execution thread is able to change a memory location between the time-of-check and time-of-use of a privileged execution thread. If an unprivileged attacker changes the value ... More
Harmonic analysis of translation invariant valuationsAug 23 2010Mar 01 2011The decomposition of the space of continuous and translation invariant valuations into a sum of SO(n) irreducible subspaces is obtained. A reformulation of this result in terms of a Hadwiger type theorem for continuous translation invariant and SO(n)-equivariant ... More
The H-Covariant Strong Picard GroupoidSep 08 2004Apr 25 2005The notion of H-covariant strong Morita equivalence is introduced for *-algebras over C = R(i) with an ordered ring R which are equipped with a *-action of a Hopf *-algebra H. This defines a corresponding H-covariant strong Picard groupoid which encodes ... More
A shortcut to (sun)flowers: Kernels in logarithmic space or linear timeApr 30 2015We investigate whether kernelization results can be obtained if we restrict kernelization algorithms to run in logarithmic space. This restriction for kernelization is motivated by the question of what results are attainable for preprocessing via simple ... More
On Semigroups of Two-Dimensional Upper-Triangular Integer MatricesMay 13 2019We analyze algorithmic problems in finitely generated semigroups of two-dimensional upper-triangular integer matrices. These semigroup problems are tightly connected with problems about compositions of affine functions over one variable. Building on a ... More
Weak Limit of the 3-State Quantum Walk on the LineApr 04 2014May 21 2014We revisit the one dimensional discrete time quantum walk with 3 states and the Grover coin. We derive analytic expressions for observed the localization, an long time approximation for the probability density function (PDF). We also connect the time ... More
Streaming KernelizationMay 06 2014Kernelization is a formalization of preprocessing for combinatorially hard problems. We modify the standard definition for kernelization, which allows any polynomial-time algorithm for the preprocessing, by requiring instead that the preprocessing runs ... More
The midpoint between dipole and parton showersJun 16 2015Sep 19 2015We present a new parton-shower algorithm. Borrowing from the basic ideas of dipole cascades, the evolution variable is judiciously chosen as the transverse momentum in the soft limit. This leads to a very simple analytic structure of the evolution. A ... More
Interactive Natural Language Acquisition in a Multi-modal Recurrent Neural ArchitectureMar 24 2017Feb 07 2018For the complex human brain that enables us to communicate in natural language, we gathered good understandings of principles underlying language acquisition and processing, knowledge about socio-cultural conditions, and insights about activity patterns ... More
Stochastic mortality models: An infinite dimensional approachJul 11 2019Demographic projections of future mortality rates involve a high level of uncertainty and require stochastic mortality models. The current paper investigates forward mortality models driven by a (possibly infinite dimensional) Wiener process and a compensated ... More
Finite-Size Corrections for Ground States of Edwards-Anderson Spin GlassesOct 28 2011May 30 2012Extensive computations of ground state energies of the Edwards-Anderson spin glass on bond-diluted, hypercubic lattices are conducted in dimensions d=3,..,7. Results are presented for bond-densities exactly at the percolation threshold, p=p_c, and deep ... More
Superstability of the yeast cell cycle dynamics: Ensuring causality in the presence of biochemical stochasticityMay 05 2006Gene regulatory dynamics is governed by molecular processes and therefore exhibits an inherent stochasticity. However, for the survival of an organism it is a strict necessity that this intrinsic noise does not prevent robust functioning of the system. ... More
Consistency of Importance Sampling estimates based on dependent sample sets and an application to models with factorizing likelihoodsMar 01 2015In this paper, I proof that Importance Sampling estimates based on dependent sample sets are consistent under certain conditions. This can be used to reduce variance in Bayesian Models with factorizing likelihoods, using sample sets that are much larger ... More
Gradient Importance SamplingJul 21 2015Adaptive Monte Carlo schemes developed over the last years usually seek to ensure ergodicity of the sampling process in line with MCMC tradition. This poses constraints on what is possible in terms of adaptation. In the general case ergodicity can only ... More
Black Hole Evaporation: Sparsity in Analogue and General Relativistic Space-TimesJan 17 2019Our understanding of black holes changed drastically, when Stephen Hawking discovered their evaporation due to quantum mechanical processes. One core feature of this effect is both its similarity and simultaneous dissimilarity to classical black body ... More
Log-Concavity Properties of Minkowski ValuationsNov 28 2014New Orlicz Brunn-Minkowski inequalities are established for rigid motion compatible Minkowski valuations of arbitrary degree. These extend classical log-concavity properties of intrinsic volumes and generalize seminal results of Lutwak and others. Two ... More
Color ordering in QCDNov 25 2013We derive color decompositions of arbitrary tree and one-loop QCD amplitudes into color ordered objects called primitive amplitudes. Furthermore, we derive general fermion flip and reversion identities spanning the null space among the primitive amplitudes ... More
Maximal rank subgroups and strong functoriality of the additive eigenconeAug 22 2016Let $G$ be a simple connected complex Lie group. The additive eigencone of $G$ is a polyhedral cone containing the set of solutions to the additive eigenvalue problem, a generalization of the Hermitian eigenvalue problem. The additive eigencone is functorial, ... More
A Bayesian Model of node interaction in networksFeb 18 2014Mar 06 2015We are concerned with modeling the strength of links in networks by taking into account how often those links are used. Link usage is a strong indicator of how closely two nodes are related, but existing network models in Bayesian Statistics and Machine ... More
Net-baryon-, net-proton-, and net-charge kurtosis in heavy-ion collisions within a relativistic transport approachMar 17 2009Sep 03 2012We explore the potential of net-baryon, net-proton and net-charge kurtosis measurements to investigate the properties of hot and dense matter created in relativistic heavy-ion collisions. Contrary to calculations in a grand canonical ensemble we explicitly ... More
Spherical centroid bodiesFeb 27 2019The spherical centroid body of a centrally-symmetric convex body in the Euclidean unit sphere is introduced. Two alternative definitions - one geometric, the other probabilistic in nature - are given and shown to lead to the same objects. The geometric ... More
Rank reduction of conformal blocksDec 12 2015Aug 03 2016Let $X$ be a smooth, pointed Riemann surface of genus zero, and $G$ a simple, simply-connected complex algebraic group. Associated to a finite number of weights of $G$ and a level is a vector space called the space of conformal blocks, and a vector bundle ... More
On the Role of Quantum Events in Double-Slit ExperimentsMar 28 2010Apr 10 2011We formulate the Schr\"odinger equation as the equation of motion of a small external influence which serves as the initial boundary condition of a physical system in classical laboratory space. The Hilbert space of possible external influences for a ... More
QCD Aspects of the NuTeV AnomalyMay 23 2004The weak mixing angle measured in neutrino scattering differs from the world average of other measurements by about 3 sigma. I discuss QCD corrections of perturbative and nonperturbative (parton structure) origin to the underlying neutrino observables. ... More
Fragmentation of PartonsOct 15 2004The concept of parton fragmentation in QCD hard scattering phenomenology as well as NLO pQCD analysis of fragmentation functions are outlined. Hadroproduction of pions of a few GeV pT is discussed through the example of recent measurements at \sqrt{S_{RHIC}}=200 ... More
Data Unfolding Methods in High Energy PhysicsNov 07 2016Nov 30 2016A selection of unfolding methods commonly used in High Energy Physics is compared. The methods discussed here are: bin-by-bin correction factors, matrix inversion, template fit, Tikhonov regularisation and two examples of iterative methods. Two procedures ... More
Theory of optimal transport for Lorentzian cost functionsJan 18 2016The optimal transport problem is studied in the context of Lorentz-Finsler geometry. For globally hyperbolic Lorentz-Finsler spacetimes the first Kantorovich problem and the Monge problem are solved. Further the intermediate regularity of the transport ... More
On Game-Theoretic Risk Management (Part Two) - Algorithms to Compute Nash-Equilibria in Games with Distributions as PayoffsNov 27 2015The game-theoretic risk management framework put forth in the precursor work "Towards a Theory of Games with Payoffs that are Probability-Distributions" (arXiv:1506.07368 [q-fin.EC]) is herein extended by algorithmic details on how to compute equilibria ... More
Tales of 1001 GluonsOct 17 2016These lectures are centred around tree-level scattering amplitudes in pure Yang-Mills theories, the most prominent example is given by the tree-level gluon amplitudes of QCD. I will discuss several ways of computing these amplitudes, illustrating in this ... More
A Short Note on Polynomial AutomorphismsOct 25 2016In this paper, we construct explicitely polynomial automorphisms of affine n-space for certain n. More precisely, we construct algebraic subgroups of the general polynomial group GA_n(k) where k is an arbitrary base ring of characteristic zero.
$C^0$-characterization and $C^0$-rigidity of symplectic and contact embeddingsJul 11 2016Jul 25 2016We present a novel C^0-characterization of symplectic embeddings and diffeomorphisms in terms of Lagrangian embeddings. Our approach is based on the shape invariant, which was discovered by J. C. Sikorav and Y. Eliashberg, intersection theory and the ... More
HS06 Benchmark for an ARM ServerNov 15 2013We benchmarked an ARM cortex-A9 based server system with a four-core CPU running at 1.1 GHz. The system used Ubuntu 12.04 as operating system and the HEPSPEC 2006 (HS06) benchmarking suite was compiled natively with gcc-4.4 on the system. The benchmark ... More
Power Corrections in Electron-Positron Annihilation: Experimental ReviewJun 20 2006Experimental studies of power corrections with e+e- data are reviewed. An overview of the available data for jet and event shape observables is given and recent analyses based on the Dokshitzer-Marchesini-Webber (DMW) model of power corrections are summarised. ... More
D-branes in a marginally deformed WZW modelDec 17 2002In this talk we discuss symmetry preserving D-branes on a line of a marginally deformed SU(2) WZW model. A semiclassical and a quantum theoretical approach are presented.
D-branes on a Deformation of SU(2)Dec 20 2001Jan 04 2002We discuss D-branes on a line of conformal field theories connected by an exact marginal deformation. The line contains an SU(2) WZW model and two mutually T-dual SU(2)/U(1) cosets times a free boson. We find the D-branes preserving a U(1) isometry, an ... More
Membrany corrections to the string anti-string potential in M5-brane theoryFeb 10 1999Mar 06 2000We study the potential between a string and an anti-string source in M5-theory by using the adS/CFT duality conjecture. We find that the next to leading order corrections in a saddle point approximation renormalize the classical result.
Measurement of the Pion Polarizability at COMPASSJan 20 2014Feb 12 2014The value of the pion polarizability is predicted with high precision by Chiral Perturbation Theory. However, the existing experimental values are at tension with this prediction as well as among themselves. The COMPASS experiment at the CERN SPS accesses ... More
Rho meson properties from combining QCD-based modelsMar 04 2003Aiming at the calculation of the properties of rho-mesons, non-perturbative QCD-based methods are discussed concerning their potentials as well as their short-comings. The latter are overcome by combining these techniques. The utilized methods are (i) ... More
Life time of resonances in transport simulationsAug 21 2000We calculate the life time of a resonance in our recently developed framework for a test-particle description of transport processes for states with continuous mass spectra. The result differs from the expression commonly used in transport simulations ... More
Information on the structure of the rho meson from the pion form-factorJul 01 2009The electromagnetic pion form-factor is calculated in a Bethe-Salpeter approach which accounts for pion rescattering. In the scattering kernel the pion-pion contact interaction from lowest-order chiral perturbation theory is considered together with an ... More
Spin Path Integrals, Berry phase, and the Quantum Phase Transition in the sub-Ohmic Spin-boson ModelJul 26 2010The quantum critical properties of the sub-Ohmic spin-1/2 spin-boson model and of the Bose-Fermi Kondo model have recently been discussed controversially. The role of the Berry phase in the breakdown of the quantum-to-classical mapping of quantum criticality ... More
A Rigidity Phenomenon for the Hardy-Littlewood Maximal FunctionOct 02 2014Nov 13 2015The Hardy-Littlewood maximal function $\mathcal{M}$ and the trigonometric function $\sin{x}$ are two central objects in harmonic analysis. We prove that $\mathcal{M}$ characterizes $\sin{x}$ in the following way: let $f \in C^{\alpha}(\mathbb{R}, \mathbb{R})$ ... More
A geometric uncertainty principle with an application to Pleijel's estimateJun 13 2013Nov 04 2013Consider partitions of an open, bounded domain in $\mathbb{R}^n$. Then an average element of the partition has either its Fraenkel asymmetry or its deviation from the smallest element in the partition bounded away from 0 by a universal constant. As an ... More
Period -- mass-loss rate relation of Miras with and without technetiumNov 05 2014We present the discovery that Mira variables separate in two distinct sequences in a near- to mid-IR color versus pulsation period diagram, if a distinction is made with respect to the presence of technetium (Tc) in the stars. Tc is an indicator of recent ... More
Period -- mass-loss rate relation of Miras with and without technetiumJun 23 2013Aims: We report the discovery that Mira variables with and without absorption lines of the element technetium (Tc) occupy two different regions in a diagram of near- to mid-infrared colour versus pulsation period. Tc is an indicator of a recent or ongoing ... More
Dynamical properties of a randomly diluted neural network with variable activityMar 08 1999The subject of study is a neural network with binary neurons, randomly diluted synapses and variable pattern activity. We look at the system with parallel updating using a probabilistic approach to solve the one step dynamics with one condensed pattern. ... More
The coherent states: old geometrical methods in new quantum clothesAug 02 1994A geometric characterization of transition amplitudes between coherent states, or equivalently, of the hermitian scalar product of holomorphic cross sections in the associated D - M tilda - module, in terms of the embedding of the cohe- rent state manifold ... More
Phase Diagram of Interacting Bosons on the Honeycomb LatticeJan 15 2007We study the ground state properties of repulsively interacting bosons on the honeycomb lattice using large-scale quantum Monte Carlo simulations. In the hard-core limit the half-filled system develops long ranged diagonal order for sufficiently strong ... More
Periods and Hodge structures in perturbative quantum field theoryFeb 04 2013Jul 06 2013There is a fruitful interplay between algebraic geometry on the one side and perturbative quantum field theory on the other side. I review the main relevant mathematical concepts of periods, Hodge structures and Picard-Fuchs equations and discuss the ... More
Feynman GraphsJan 29 2013In these lectures I discuss Feynman graphs and the associated Feynman integrals. Of particular interest are the classes functions, which appear in the evaluation of Feynman integrals. The most prominent class of functions is given by multiple polylogarithms. ... More
Introduction to Feynman IntegralsMay 11 2010In these lectures I will give an introduction to Feynman integrals. In the first part of the course I review the basics of the perturbative expansion in quantum field theories. In the second part of the course I will discuss more advanced topics: Mathematical ... More
Status of NNLO 3-jet calculationsAug 25 2004The process e+ e- -> 3 jets offers the opportunity to measure the strong coupling constant. For an accurate determination, precise theoretical calculations are necessary. I will give an overview on the status of the next-to-next-to-leading order calculations. ... More
Subtraction terms for one-loop amplitudes with one unresolved partonJun 25 2003Fully differential next-to-next-to-leading order calculations require a method to cancel infrared singularities. In a previous publication, I discussed the general setup for the subtraction method at NNLO. In this paper I give all subtraction terms for ... More
gTybalt - a free computer algebra systemApr 29 2003This article documents the free computer algebra system "gTybalt". The program is build on top of other packages, among others GiNaC, TeXmacs and Root. It offers the possibility of interactive symbolic calculations within the C++ programming language. ... More
Computer Algebra in Particle PhysicsSep 20 2002These lectures given to graduate students in theoretical particle physics, provide an introduction to the ``inner workings'' of computer algebra systems. Computer algebra has become an indispensable tool for precision calculations in particle physics. ... More
Theoretical overview on top pair production and single top productionJan 19 2012In this talk I will give an overview on theoretical aspects of top quark physics. The focus lies on top pair production and single top production.
Symmetry breaking of gauge theories down to Abelian sub-groupsFeb 14 2008I re-derive the lowest order effective Lagrangian for electro-weak symmetry breaking without the use of Goldstone's theorem for spontaneously broken global symmetries and without the assumption of a custodial symmetry. I consider the breaking of a local ... More
Automated computation of spin- and colour-correlated Born matrix elementsOct 12 2005I report on an implementation of an algorithm for the automated numerical calculation of spin- and colour-correlated Born matrix elements in QCD. These spin- and colour-correlated matrix elements are needed for NLO calculations in combination with the ... More
Algebraic Algorithms in Perturbative CalculationsMay 30 2003I discuss algorithms for the evaluation of Feynman integrals. These algorithms are based on Hopf algebras and evaluate the Feynman integral to (multiple) polylogarithms.
Status of Identification of VHE gamma-ray sourcesSep 20 2006With the recent advances made by Cherenkov telescopes such as H.E.S.S., the field of very high-energy (VHE) gamma-ray astronomy has recently entered a new era in which for the first time populations of Galactic sources such as e.g. Pulsar wind nebulae ... More
Uncertainties of Sudakov form factorsDec 22 2004We study the uncertainties of Sudakov form factors as the basis for parton shower evolution in Monte Carlo event generators. We discuss the particular cases of systematic uncertainties of parton distribution functions and scale uncertainties.
Event Generators - New DevelopmentsOct 22 2002After an introduction to event generators we give an overview of developments in the field of joining matrix elements with parton showers. Starting with matrix element corrections, we also discuss implementations that match LO and NLO matrix elements ... More
NLO corrections to the photon impact factorAug 15 2002We review the program of the calculation of next-to-leading order corrections to the virtual photon impact factor. Following a brief introduction we present some technical aspects for the various contributions. Recently obtained results for transversely ... More
γ-rays from starburst galaxiesOct 25 2012In this paper the current status of \gamma-ray observations of starburst galaxies from hundreds of MeV up to TeV energies with space-based instruments and ground-based Imaging Atmospheric Cherenkov Telescopes (IACTs) is summarised. The properties of the ... More
Transport through a Constriction in a FQH AnnulusSep 30 1997The composite fermion perspective is used, to study the flux dependence of thermodynamic properties of an annulus in the fractional quantum hall state at odd inverse filling factor. It is shown that $\phi_0$- periodicity is restored, if there is tunneling ... More
Flavour-Dependent Type II LeptogenesisApr 12 2007Sep 11 2008We reanalyse leptogenesis via the out-of-equilibrium decay of the lightest right-handed neutrino in type II seesaw scenarios, taking into account flavour-dependent effects. In the type II seesaw mechanism, in addition to the type I seesaw contribution, ... More
Renormalization Group Analysis of Neutrino Mass ParametersAug 20 2002Tools for calculating the Renormalization Group Equations for renormalizable and non-renormalizable operators in various theories are reviewed, which are essential for comparing experimental results with predictions from models beyond the Standard Model. ... More
Plateau's problem for integral currents in locally non-compact metric spacesMar 23 2012The purpose of this article is to prove existence of mass minimizing integral currents with prescribed possibly non-compact boundary in all dual Banach spaces and furthermore in certain spaces without linear structure, such as injective metric spaces ... More
Gromov hyperbolic spaces and the sharp isoperimetric constantSep 11 2006Mar 20 2007In this article we exhibit the largest constant in a quadratic isoperimetric inequality which ensures that a geodesic metric space is Gromov hyperbolic. As a particular consequence we obtain that Euclidean space is a borderline case for Gromov hyperbolicity ... More
Equivariant properties of symmetric productsMar 06 2014The filtration on the infinite symmetric product of spheres by the number of factors provides a sequence of spectra between the sphere spectrum and the integral Eilenberg-Mac Lane spectrum. This filtration has received a lot of attention and the subquotients ... More
Effective descent maps for schemesJun 11 2001Feb 01 2003The paper is withdrawn due to mistakes in the proofs for Proposition 1.2 and Theorem 2.2.
Simulation of Z plus Graviton/Unparticle Production at the LHCSep 27 2008Feb 09 2009Theories with extra dimensions have gained much interest in recent years as candidates for a possible extension of the SM. The observation of large extra dimensions through real graviton emission is one of the most popular related new phenomena. The main ... More
Status of the Forward Physics Projects in ATLASJun 05 2007The ATLAS experiment at the LHC is building several detector systems for forward physics studies and to determine the luminosity. The main forward systems consist of a Cerenkov detector called LUCID, a Zero Degree Calorimeter (ZDC) and Roman Pots which ... More
Recent developments in deformation quantizationJan 31 2015In this review an overview on some recent developments in deformation quantization is given. After a general historical overview we motivate the basic definitions of star products and their equivalences both from a mathematical and a physical point of ... More
Deformation Quantization: Observable Algebras, States and Representation TheoryMar 10 2003In these lecture notes I give an introduction to deformation quantization. The quantization problem is discussed in some detail thereby motivating the notion of star products. Starting from a deformed observable algebra, i.e. the star product algebra, ... More
A Nuclear Weyl AlgebraSep 25 2012Jun 13 2013A bilinear form on a possibly graded vector space $V$ defines a graded Poisson structure on its graded symmetric algebra together with a star product quantizing it. This gives a model for the Weyl algebra in an algebraic framework, only requiring a field ... More