total 1974took 0.10s

Bordism of constrained Morse functionsMar 29 2018We call a Morse function $f$ on a closed manifold $k$-constrained if neither $f$ nor $-f$ has critical points of indefinite Morse index $< k$. In this paper we study bordism groups of $k$-constrained Morse functions, and thus interpolate between the case ... More

Singular Patterns of Generic Maps of Surfaces with Boundary into the PlaneFeb 11 2019For generic maps from compact surfaces with boundary into the plane we develop an explicit algorithm for minimizing both the number of cusps and the number of components of the singular locus. More precisely, we minimize among maps with fixed boundary ... More

Cusp cobordism group of Morse functionsMay 14 2019By a Morse function on a compact manifold with boundary we mean a real-valued function without critical points near the boundary such that its critical points as well as the critical points of its restriction to the boundary are all non-degenerate. For ... More

Standard Special Generic Maps of Homotopy Spheres into Euclidean SpacesJul 26 2017Aug 03 2017A so-called special generic map is by definition a map of smooth manifolds all of whose singularities are definite fold points. It is in general an open problem posed by Saeki in 1993 to determine the set of integers $p$ for which a given homotopy sphere ... More

A fundamental class for intersection spaces of depth one Witt spacesApr 07 2019By a theorem of Banagl-Chriestenson, intersection spaces of depth one pseudomanifolds exhibit generalized Poincar\'{e} duality of Betti numbers, provided that certain characteristic classes of the link bundles vanish. In this paper, we show that the middle-perversity ... More

The chromatic Brauer category and its linear representationsFeb 14 2019The Brauer category is a symmetric strict monoidal category that arises as a categorification of the Brauer algebras in the context of Banagl's framework of positive topological field theories (TFTs). We introduce the chromatic Brauer category as an enrichment ... More

Search for single-top production with the ZEUS detector at HERAAug 23 2003A search for anomalous single-top production, ep -> etX, t -> Wb, has been made with the ZEUS detector at HERA using an integrated luminosity of 130 pb^-1. No evidence for top-quark production was found in either the leptonic or the hadronic decay channel ... More

Revealing stellar brightness profiles by means of microlensing fold causticsFeb 24 2004Jun 23 2004With a handful of measurements of limb-darkening coefficients, galactic microlensing has already proven to be a powerful technique for studying atmospheres of distant stars. Survey campaigns such as OGLE-III are capable of providing ~ 10 suitable target ... More

Determining the abundance of extragalactic planetsSep 23 2003Oct 23 2003Gravitational microlensing provides a unique technique to reveal information about extragalactic planets. A network of at least four 2m-class telescopes distributed around the northern hemisphere could probe 15-35 jupiters and 4-10 saturns around M31 ... More

The binary gravitational lens and its extreme casesMar 01 1999Sep 10 1999The transition of the binary gravitational lens from the equal mass case to small (planetary) mass ratios q is studied. It is shown how the limit of a (pure shear) Chang-Refsdal lens is approached, under what conditions the Chang-Refsdal approximation ... More

$Σ_2^p$-complete Problems on Hedonic GamesSep 08 2015Hedonic games provide a general model of coalition formation, in which a set of agents is partitioned into coalitions, with each agent having preferences over which other players are in her coalition. We prove that with additively separable preferences, ... More

Inhomogeneous phases in the Nambu-Jona-Lasino and quark-meson modelJun 29 2009We discuss inhomogeneous ground states of the Nambu-Jona-Lasino (NJL) and quark-meson (QM) model within mean-field approximation and their possible existence in the respective phase diagrams. For this purpose we focus on lower dimensional modulations ... More

Unsatisfiable Linear k-CNFs Exist, for every kAug 17 2007We call a CNF formula linear if any two clauses have at most one variable in common. Let Linear k-SAT be the problem of deciding whether a given linear k-CNF formula is satisfiable. Here, a k-CNF formula is a CNF formula in which every clause has size ... More

PPZ For More Than Two Truth Values - An Algorithm for Constraint Satisfaction ProblemsOct 27 2010We analyze the so-called ppz algorithm for (d,k)-CSP problems for general values of d (number of values a variable can take) and k (number of literals per constraint). To analyze its success probability, we prove a correlation inequality for submodular ... More

Is there a physically universal cellular automaton or Hamiltonian?Sep 09 2010It is known that both quantum and classical cellular automata (CA) exist that are computationally universal in the sense that they can simulate, after appropriate initialization, any quantum or classical computation, respectively. Here we introduce a ... More

Corrections of Order $αα_s$ to W Boson DecaysJul 26 2013Nov 30 2015We present the calculation of the mixed two-loop QCD/electroweak corrections to hadronic W boson decays within the Standard Model. The optical theorem is applied to the W boson two-point function. The multi-scale integrals are computed with the help of ... More

Non-Autonomous Forms and InvarianceSep 13 2016We generalize the Beurling--Deny--Ouhabaz criterion for parabolic evolution equations governed by forms to the non-autonomous, non-homogeneous and semilinear case. Let $V, H$ are Hilbert spaces such that $V$ is continuously and densely embedded in $H$ ... More

Decomposition of time-covariant operations on quantum systems with continuous and/or discrete energy spectrumJul 19 2004Sep 30 2004Every completely positive map G that commutes which the Hamiltonian time evolution is an integral or sum over (densely defined) CP-maps G_\sigma where \sigma is the energy that is transferred to or taken from the environment. If the spectrum is non-degenerated ... More

(g-2)_mu and supersymmetry: status and prospectsOct 12 2007The experimental determination of the muon magnetic moment and its theoretical prediction within the Standard Model and the MSSM are reviewed. A 3 sigma deviation between experiment and Standard Model prediction has been established, and supersymmetry ... More

On causally asymmetric versions of Occam's Razor and their relation to thermodynamicsAug 24 2007Jan 30 2009In real-life statistical data, it seems that conditional probabilities for the effect given their causes tend to be less complex and smoother than conditionals for causes, given their effects. We have recently proposed and tested methods for causal inference ... More

On the entropy production of time series with unidirectional linearityAug 13 2009There are non-Gaussian time series that admit a causal linear autoregressive moving average (ARMA) model when regressing the future on the past, but not when regressing the past on the future. The reason is that, in the latter case, the regression residuals ... More

Equivariant $Γ$-spacesApr 30 2014The aim of this note is to provide a comprehensive treatment of the homotopy theory of $\Gamma$-$G$-spaces for $G$ a finite group. We introduce two level and stable model structures on $\Gamma$-$G$-spaces and exhibit Quillen adjunctions to $G$-symmetric ... More

Adaptive Contouring -- an efficient way to calculate microlensing light curves of extended sourcesMar 13 2007The availability of a robust and efficient routine for calculating light curves of a finite source magnified due to bending its light by the gravitational field of an intervening binary lens is essential for determining the characteristics of planets ... More

Lens binarity vs limb darkening in close-impact galactic microlensing eventsOct 18 2004Although point caustics harbour a larger potential for measuring the brightness profile of stars during the course of a microlensing event than (line-shaped) fold caustics, the effect of lens binarity significantly limits the achievable accuracy. Therefore, ... More

Uncovering stellar atmospheres with gravitational microlensing telescopesDec 08 2003A strong differential magnification over the face of the source star passing the caustic created by a binary lens star allows to measure its radial intensity profile with an angular resolution of 20-60 nas from broad-band photometric observations for ... More

Simple expression for the quantum Fisher information matrixJan 03 2018Apr 12 2018Quantum Fisher information matrix (QFIM) is a cornerstone of modern quantum metrology and quantum information geometry. Apart from optimal estimation, it finds applications in description of quantum speed limits, quantum criticality, quantum phase transitions, ... More

Nonparametric Testing for Differences in Electricity Prices: The Case of the Fukushima Nuclear AccidentNov 09 2017Nov 29 2018This work is motivated by the problem of testing for differences in the mean electricity prices before and after Germany's abrupt nuclear phaseout after the nuclear disaster in Fukushima Daiichi, Japan, in mid-March 2011. Taking into account the nature ... More

Rigid realizations of modular forms in Calabi--Yau threefoldsMay 11 2017We construct examples of modular rigid Calabi--Yau threefolds, which give a realization of some new weight 4 cusp forms.

Das Internet-Adressbuch bedroht unsere PrivatsphäreMar 17 2017This paper summarizes selected results of the dissertation "Beobachtungsm\"oglichkeiten im Domain Name System: Angriffe auf die Privatsph\"are und Techniken zum Selbstdatenschutz". The dissertation provides new technical insights to answer the questions ... More

On the subexponential growth of groups acting on rooted treesFeb 26 2017We show that every group in a large family of (not necessarily torsion) spinal groups acting on the ternary rooted tree is of subexponential growth.

A nonparametric test for a constant correlation matrixOct 04 2012Oct 27 2014We propose a nonparametric procedure to test for changes in correlation matrices at an unknown point in time. The new test requires only mild assumptions on the serial dependence structure and has considerable power in finite samples. We derive the asymptotic ... More

Topological entropy and distributional chaos in hereditary shifts with applications to spacing shifts and beta shiftsNov 01 2011Jan 08 2012Positive topological entropy and distributional chaos are characterized for hereditary shifts. A hereditary shift has positive topological entropy if and only if it is DC2-chaotic (or equivalently, DC3-chaotic) if and only if it is not uniquely ergodic. ... More

Infinitely presented C(6)-groups are SQ-universalNov 26 2014We prove that infinitely presented classical $C(6)$ small cancellation groups are SQ-universal. We extend the result to graphical $Gr_*(6)$-groups over free products. For every $p\in\mathbb{N}$, we construct uncountably many pairwise non-quasi-isometric ... More

Non-Autonomous Maximal Regularity for Forms of Bounded VariationJun 11 2014Jun 12 2014We consider a non-autonomous evolutionary problem \[ u' (t)+\mathcal A (t)u(t)=f(t), \quad u(0)=u_0, \] where $V, H$ are Hilbert spaces such that $V$ is continuously and densely embedded in $H$ and the operator $\mathcal A (t)\colon V\to V^\prime$ is ... More

The Zak transform on strongly proper $G$-spaces and its applicationsMay 17 2016The Zak transform on $\mathbb{R}^d$ is an important tool in condensed matter physics, signal processing, time-frequency analysis, and harmonic analysis in general. This article introduces a generalization of the Zak transform to a class of locally compact ... More

Quantum thermodynamics with missing reference frames: Decompositions of free energy into non-increasing componentsNov 30 2005If an absolute reference frame with respect to time, position, or orientation is missing one can only implement quantum operations which are covariant with respect to the corresponding unitary symmetry group G. Extending observations of Vaccaro et al., ... More

Some Considerations on the Additional Absorption Peak in the c-axis Conductivity of Bilayer Cuprate Superconductors: Interpretation of the Changes Induced by a Parallel Magnetic Field and the Role of Bilayer SplittingAug 02 2004Changes of the 400 cm^{-1} peak in the c-axis conductivity of underdoped YBa2Cu3O6.6 upon application of a parallel magnetic field reported by Kojima et al. are shown to be consistent with the model where the peak is due to the superfluid. Results of ... More

Note on a Conjecture of WegnerJan 10 2008Jun 13 2011The optimal packings of n unit discs in the plane are known for those natural numbers n, which satisfy certain number theoretic conditions. Their geometric realizations are the extremal Groemer packings (or Wegner packings). But an extremal Groemer packing ... More

Anti-Proportional Bandwidth Selection for Smoothing (Non-)Sparse Functional Data with Covariate AdjustmentsJan 28 2016Jun 24 2016This paper deals with the nonparametric estimation of the conditional mean and covariance function of a stationary time series of weakly dependent random functions with covariate-adjustments. As in the context of sparse functional data, it is assumed ... More

Unsatisfiable Linear CNF Formulas Are Large and ComplexMay 11 2009Oct 28 2010We call a CNF formula linear if any two clauses have at most one variable in common. We show that there exist unsatisfiable linear k-CNF formulas with at most 4k^2 4^k clauses, and on the other hand, any linear k-CNF formula with at most 4^k/(8e^2k^2) ... More

Modeling and forecasting electricity spot prices: A functional data perspectiveOct 06 2013Nov 28 2013Classical time series models have serious difficulties in modeling and forecasting the enormous fluctuations of electricity spot prices. Markov regime switch models belong to the most often used models in the electricity literature. These models try to ... More

Evolutionary Dynamics of Giant Viruses and their VirophagesJan 25 2013Giant viruses contain large genomes, encode many proteins atypical for viruses, replicate in large viral factories, and tend to infect protists. The giant virus replication factories can in turn be infected by so called virophages, which are smaller viruses ... More

Inhomogeneous phases near the chiral critical point in NJL-type modelsAug 26 2009In this talk we discuss the role of inhomogeneous phases in the phase diagram of the Nambu-Jona-Lasinio (NJL) and the quark meson (QM) model. By means of a generalized Ginzburg-Landau (GL) expansion it is concluded that the critical point in the mean-field ... More

Where are the binary source galactic microlensing events?Jan 13 1998Though there have been some galactic microlensing events which show a clear signature of a binary lens, no event has yet been claimed as due to lensing of a binary source. Here I argue that this may be due to the fact that most of the binary source events ... More

Estimating physical quantities for an observed galactic microlensing eventJan 08 1997Nov 13 1997For a given spatial distribution of the lenses and distribution of the transverse velocity of the lens relative to the line-of-sight, a probability distribution for the lens mass for a single observed event is derived. In addition, similar probability ... More

Uncovering galactic and extragalactic planets by gravitational microlensingDec 08 2003With its planet detection efficiency reaching a maximum for orbital radii between 1 and 10 AU, microlensing provides a unique sensitivity to planetary systems similar to our own around galactic and even extragalactic stars acting as lenses on observed ... More

Ambiguities in fits of binary lens galactic microlensing eventsFeb 28 1997Aug 13 1998For observed galactic microlensing events only one fit is usually presented, though, especially for a binary lens, several fits may be possible. This has been shown for the MACHO LMC#1 event (Dominik & Hirshfeld 1996). Here I discuss the strong binary ... More

Hodge Numbers of Generalised Borcea-Voisin ThreefoldsFeb 16 2017We shall reproof formulas for the Hodge numbers of Calabi-Yau threefolds of Borcea-Voisin type constructed by A. Cattaneo and A. Garbagnati, using the orbifold cohomology formula and the orbifold Euler characteristic.

Mixing times for the simple exclusion process in ballistic random environmentJun 11 2018Mar 04 2019We consider the exclusion process on segments of the integers in a site-dependent random environment. We assume to be in the ballistic regime in which a single particle has positive linear speed. Our goal is to study the mixing time of the exclusion process ... More

Abelian varieties with quaternion and complex multiplicationAug 28 2012In this paper we study abelian varieties which correspond to CM points in the coarse moduli space of principally polarized abelian varieties with multiplication by a maximal order in a quaternion algebra over a totally real number field. These are abelian ... More

Separate Chaining Meets Compact HashingMay 01 2019While separate chaining is a common strategy for resolving collisions in a hash table taught in most textbooks, compact hashing is a less common technique for saving space when hashing integers whose domain is relatively small with respect to the problem ... More

Can microlensing fold caustics reveal a second stellar limb-darkening coefficient?Mar 09 2004May 17 2004Dense high-precision photometry of microlensed stars during a fold-caustic passage can be used to reveal their intensity profiles from which the temperature of the stellar atmosphere as function of fractional radius can be derived. While the capabilities ... More

Spin-1/2 particles moving on a 2D lattice with nearest-neighbor interactions can realize an autonomous quantum computerJun 30 2005Dec 12 2006What is the simplest Hamiltonian which can implement quantum computation without requiring any control operations during the computation process? In a previous paper we have constructed a 10-local finite-range interaction among qubits on a 2D lattice ... More

Pseudodifferentialoperatoren mit nichtglatten Koeffizienten auf MannigfaltigkeitenNov 07 2013A generalization of differential operators are pseudodifferential operators which are used for reasoning about partial differential equations with variable coefficients. A lot of useful properties about classical pseudodifferential operators are already ... More

Optimal Scheduling for Linear-Rate Multi-Mode SystemsFeb 18 2013Linear-Rate Multi-Mode Systems is a model that can be seen both as a subclass of switched linear systems with imposed global safety constraints and as hybrid automata with no guards on transitions. We study the existence and design of a controller for ... More

Particle number conservation in quantum many-body simulations with matrix product operatorsApr 08 2011Oct 06 2011Incorporating conservation laws explicitly into matrix product states (MPS) has proven to make numerical simulations of quantum many-body systems much less resources consuming. We will discuss here, to what extent this concept can be used in simulation ... More

Mixing times for the simple exclusion process in ballistic random environmentJun 11 2018We consider the exclusion process on segments of the integers in a site- dependent random environment. We assume to be in the ballistic regime in which a single particle has positive linear speed. Our goal is to study the mixing time of the exclusion ... More

The non-existence of sharply $2$-transitive sets of permutations in $\mathrm{Sp}(2d,2)$ of degree $2^{2d-1} \pm 2^{d-1}$Feb 16 2016We use M\"uller and Nagy's method of contradicting subsets to give a new proof for the non-existence of sharply $2$-transitive subsets of the symplectic groups $\mathrm{Sp}(2d,2)$ in their doubly-transitive actions of degrees $2^{2d-1}\pm 2^{d-1}$. The ... More

Effective potential for Polyakov loops from a center symmetric effective theory in three dimensionsNov 20 2009Jul 04 2012We present lattice simulations of a center symmetric dimensionally reduced effective field theory for SU(2) Yang Mills which employ thermal Wilson lines and three-dimensional magnetic fields as fundamental degrees of freedom. The action is composed of ... More

On the Computational Power of Molecular Heat EnginesFeb 02 2005A heat engine is a machine which uses the temperature difference between a hot and a cold reservoir to extract work. Here both reservoirs are quantum systems and a heat engine is described by a unitary transformation which decreases the average energy ... More

Quantum algorithm for measuring the energy of n qubits with unknown pair-interactionsAug 10 2001The well-known algorithm for quantum phase estimation requires that the considered unitary is available as a conditional transformation depending on the quantum state of an ancilla register. We present an algorithm converting an unknown n-qubit pair-interaction ... More

Satisfiability of Almost Disjoint CNF FormulasJul 08 2008Jul 10 2008We call a CNF formula linear if any two clauses have at most one variable in common. Let m(k) be the largest integer m such that any linear k-CNF formula with <= m clauses is satisfiable. We show that 4^k / (4e^2k^3) <= m(k) < ln(2) k^4 4^k. More generally, ... More

Using a Skewed Hamming Distance to Speed Up Deterministic Local SearchMay 26 2010Schoening presents a simple randomized algorithm for (d,k)-CSP problems with running time (d(k-1)/k)^n poly(n). Here, d is the number of colors, k is the size of the constraints, and n is the number of variables. A derandomized version of this, given ... More

How many phases meet at the chiral critical point?Feb 10 2009Aug 25 2009We explore the phase diagram of NJL-type models near the chiral critical point allowing for phases with spatially inhomogeneous chiral condensates. In the chiral limit it turns out that the region in the mean-field phase diagram where those phases are ... More

Parameter degeneracies and (un)predictability of gravitational microlensing eventsNov 25 2008(abridged) Some difficulties in determining the physical properties that lead to observed anomalies in microlensing light curves, such as the mass and separation of extra-solar planets orbiting the lens star, or the relative source-lens parallax, are ... More

Theory and practice of microlensing lightcurves around fold singularitiesSep 22 2003Jun 23 2004Among all galactic microlensing events, those involving a passage of the observed source star over the caustic created by a binary lens are particularly useful in providing information about stellar atmospheres, the dynamics of stellar populations in ... More

A robust and efficient method for calculating the magnification of extended sources caused by gravitational lensesApr 06 1998To determine the magnification of an extended source caused by gravitational lensing one has to perform a two-dimensional integral over point-source magnifications in general. Since the point-source magnification jumps to an infinite value on caustics, ... More

Galactic microlensing with rotating binariesFeb 04 1997Sep 09 1997The influence of rotating binary systems on the light curves of galactic microlensing events is studied. Three different rotating binary systems are discussed: a rotating binary lens, a rotating binary source, and the motion of the earth around the sun ... More

Planetary mass function and planetary systemsSep 23 2010With planets orbiting stars, a planetary mass function should not be seen as a low-mass extension of the stellar mass function, but a proper formalism needs to take care of the fact that the statistical properties of planet populations are linked to the ... More

Stochastical distributions of lens and source properties for observed galactic microlensing eventsJul 22 2005Dec 27 2005A comprehensive new approach is presented for deriving probability densities of physical properties characterizing lens or source that constitute an observed galactic microlensing event. While previously encountered problems are overcome, constraints ... More

A Lensing View On The Fundamental PlaneAug 05 2009For lensing galaxies we introduce a formal velocity dispersion sigma_lens, based on enclosed mass and the virial theorem. This is calculated from an ensemble of pixelated lens models, and found to be fairly model independent. A sample of 18 well-known ... More

Vertex-Detector R&D for CLICDec 19 2013A detector concept based on hybrid planar pixel-detector technology is under development for the CLIC vertex detector. It comprises fast, low-power and small-pitch readout ASICs implemented in 65 nm CMOS technology (CLICpix) coupled to ultra-thin sensors ... More

Probing Extra Dimensions with ATLASNov 02 2006In the late nineties several authors suggested that the extra dimensions predicted by string theory might lead to observable effects at high energy colliders. The ATLAS experiment which will start taking data at the LHC in 2007 will be an excellent place ... More

On Uniqueness of Weak Solutions for the Thin-Film EquationOct 23 2013In any number of space variables, we study the Cauchy problem related to the thin-film equation in the simplest case of a linearly degenerate mobility. This equation, derived from a lubrication approximation, also models the surface tension dominated ... More

Data Sampling Strategies in Stochastic Algorithms for Empirical Risk MinimizationApr 02 2018Gradient descent methods and especially their stochastic variants have become highly popular in the last decade due to their efficiency on big data optimization problems. In this thesis we present the development of data sampling strategies for these ... More

Modeling Activation Processes in Human Memory to Improve Tag RecommendationsMar 08 2018This thesis was submitted by Dr. Dominik Kowald to the Institute of Interactive Systems and Data Science of Graz University of Technology in Austria on the 5th of September 2017 for the attainment of the degree 'Dr.techn'. The supervisors of this thesis ... More

Single-Peakedness and Total Unimodularity: Efficiently Solve Voting Problems Without Even TryingSep 12 2016Many NP-hard winner determination problems admit polynomial-time algorithms when restricting inputs to be single-peaked. Commonly, such algorithms employ dynamic programming along the underlying axis. We introduce a new technique: carefully chosen integer ... More

Modeling Cognitive Processes in Social Tagging to Improve Tag RecommendationsMay 30 2018With the emergence of Web 2.0, tag recommenders have become important tools, which aim to support users in finding descriptive tags for their bookmarked resources. Although current algorithms provide good results in terms of tag prediction accuracy, they ... More

The Zak transform on strongly proper $G$-spaces and its applicationsMay 17 2016Oct 21 2016The Zak transform on $\mathbb{R}^d$ is an important tool in condensed matter physics, signal processing, time-frequency analysis, and harmonic analysis in general. This article introduces a generalization of the Zak transform to a class of locally compact ... More

Automorphism Supergroups Of SupermanifoldsApr 10 2015A classical theorem states that the group of automorphisms of a manifold $M$ preserving a $G$-structure of finite type is a Lie group. We generalize this statement to the category of $cs$ manifolds and give some examples, some of which being generalizations ... More

Lattice simulation of a center symmetric three-dimensional effective theory for SU(2) Yang-MillsOct 07 2008We perform simulations of an effective theory of SU(2) Wilson lines in three dimensions. Our action includes a kinetic term, the one-loop perturbative potential for the Wilson line, a non-perturbative "fuzzy-bag" contribution and spatial gauge fields. ... More

Infinite finitely generated automata semigroups have infinite orbitsJan 30 2018We prove that the semigroup generated by a finite state Mealy automaton $\mathcal{A}=(Q,A,\tau)$ is infinite if and only if there exists some right-infinite word in the alphabet $A$ with infinite orbit.

Groups with graphical C(6) and C(7) small cancellation presentationsSep 30 2012Jul 24 2014We extend fundamental results of small cancellation theory to groups whose presentations satisfy the generalizations of the classical C(6) and C(7) conditions in graphical small cancellation theory. Using these graphical small cancellation conditions, ... More

On Probabilistic Parallel Programs with Process Creation and SynchronisationDec 14 2010We initiate the study of probabilistic parallel programs with dynamic process creation and synchronisation. To this end, we introduce probabilistic split-join systems (pSJSs), a model for parallel programs, generalising both probabilistic pushdown systems ... More

Collisional evolution of dust aggregates. From compaction to catastrophic destructionSep 17 2009The coagulation of dust aggregates occurs in various astrophysical environments. Each one is characterized by different conditions that influence the growth, e.g. relative velocities, composition, and size of the smallest constituents (monomers). Here ... More

Supersymmetric Dark Matter and the Extragalactic Gamma Ray BackgroundMay 12 2004Apr 06 2005We trace the origin of the newly determined extragalactic gamma ray background from EGRET data to an unresolved population of blazars and neutralino annihilation in cold dark matter halos. Using results of high-resolution simulations of cosmic structure ... More

Quantum algorithm for finding periodicities in the spectrum of a black-box Hamiltonian or unitary transformationAug 10 2001Estimating the eigenvalues of a unitary transformation U by standard phase estimation requires the implementation of controlled-U-gates which are not available if U is only given as a black box. We show that a simple trick allows to measure eigenvalues ... More

BQP-complete Problems Concerning Mixing Properties of Classical Random Walks on Sparse GraphsOct 27 2006Oct 28 2006We describe two BQP-complete problems concerning properties of sparse graphs having a certain symmetry. The graphs are specified by efficiently computable functions which output the adjacent vertices for each vertex. Let i and j be two given vertices. ... More

Maximal subgroups of groups of intermediate growthNov 03 2016Finding the number of maximal subgroups of infinite index of a finitely generated subgroup is a natural problem that has been solved for several classes of "geometric" groups (linear groups, hyperbolic groups, mapping class groups, etc). Here we provide ... More

Representing sparse Gaussian DAGs as sparse R-vines allowing for non-Gaussian dependenceApr 14 2016Modeling dependence in high dimensional systems has become an increasingly important topic. Most approaches rely on the assumption of a joint Gaussian distribution such as statistical models on directed acyclic graphs (DAGs). They are based on modeling ... More

Inhomogeneous phases of strongly interacting matterNov 12 2009We discuss possible inhomogeneous phases in two regions of the QCD phase diagram: We begin with color superconducting quark matter at moderately high densities, which is an imbalanced Fermi system due to the finite strange quark mass and neutrality constraints. ... More

Driving the Gaseous Evolution of Massive Galaxies in the Early UniverseFeb 09 2012Studies of the molecular interstellar medium that fuels star formation and supermassive black hole growth in galaxies at cosmological distances have undergone tremendous progress over the past few years. Based on the detection of molecular gas in >120 ... More

How much is a quantum controller controlled by the controlled system?Aug 10 2007Aug 21 2007We consider unitary transformations on a bipartite system A x B. To what extent entails the ability to transmit information from A to B the ability to transfer information in the converse direction? We prove a dimension-dependent lower bound on the classical ... More

The Complexity of Nash Equilibria in Stochastic Multiplayer GamesSep 19 2011Sep 27 2011We analyse the computational complexity of finding Nash equilibria in turn-based stochastic multiplayer games with omega-regular objectives. We show that restricting the search space to equilibria whose payoffs fall into a certain interval may lead to ... More

Using Dimensional Reduction for Hadronic CollisionsJul 28 2008We discuss how to apply regularization by dimensional reduction for computing hadronic cross sections at next-to-leading order. We analyze the infrared singularity structure, demonstrate that there are no problems with factorization, and show how to use ... More

Factorization and Regularization by Dimensional ReductionAug 19 2005Sep 11 2005Since an old observation by Beenakker et al, the evaluation of QCD processes in dimensional reduction has repeatedly led to terms that seem to violate the QCD factorization theorem. We reconsider the example of the process gg->ttbar and show that the ... More

Minimally-disturbing Heisenberg-Weyl symmetric measurements using hard-core collisions of Schrödinger particlesJul 11 2005Jul 04 2006In a previous paper we have presented a general scheme for the implementation of symmetric generalized measurements (POVMs) on a quantum computer. This scheme is based on representation theory of groups and methods to decompose matrices that intertwine ... More

Tail Asymptotics of Random Sum and Maximum of Log-Normal RisksJan 18 2014In this paper we derive the asymptotic behaviour of the survival function of both random sum and random maximum of log-normal risks. As for the case of finite sum and maximum investigated in Asmussen and Rojas-Nandaypa (2008) also for the more general ... More

FeynArts model file for MSSM transition counterterms from DREG to DREDSep 29 2011The FeynArts model file MSSMdreg2dred.mod implements MSSM transition counterterms which can convert one-loop Green functions from dimensional regularization to dimensional reduction. They correspond to a slight extension of the well-known Martin/Vaughn ... More

Analytic Solutions for Cosmological Perturbations in Multi-Dimensional Space-TimeJun 07 1993Nov 08 1993We obtain analytic solutions for the density contrast and the anisotropic pressure in a multi-dimensional FRW cosmology with collisionless, massless matter. These are compared with perturbations of a perfect fluid universe. To describe the metric perturbations ... More