Results for "Mathias Steiner"

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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
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
Bots vs. Wikipedians, Anons vs. Logged-InsFeb 03 2014Feb 05 2014Wikipedia is a global crowdsourced encyclopedia that at time of writing is available in 287 languages. Wikidata is a likewise global crowdsourced knowledge base that provides shared facts to be used by Wikipedias. In the context of this research, we have ... More
Quantum ChaosFeb 07 1994A short historical overview is given on the development of our knowledge of complex dynamical systems with special emphasis on ergodicity and chaos, and on the semiclassical quantization of integrable and chaotic systems. The general trace formula is ... More
Telling Breaking News Stories from Wikipedia with Social Multimedia: A Case Study of the 2014 Winter OlympicsMar 17 2014With the ability to watch Wikipedia and Wikidata edits in realtime, the online encyclopedia and the knowledge base have become increasingly used targets of research for the detection of breaking news events. In this paper, we present a case study of the ... More
Magnetic Coupling in the Quiet Solar AtmosphereApr 13 2009Three kinds of magnetic couplings in the quiet solar atmosphere are highlighted and discussed, all fundamentally connected to the Lorentz force. First the coupling of the convecting and overshooting fluid in the surface layers of the Sun with the magnetic ... More
Do Black Holes Exist in a Finite Universe Having the Topology of a Flat 3-Torus?Aug 10 2016Based on perturbation theory, we present the exact first-order solution to the Einstein equations for the exterior static gravitational field of an isolated non-rotating star in a spatially finite universe having the topology of a flat 3-torus. Since ... More
Wikipedia Tools for Google SpreadsheetsFeb 08 2016In this paper, we introduce the Wikipedia Tools for Google Spreadsheets. Google Spreadsheets is part of a free, Web-based software office suite offered by Google within its Google Docs service. It allows users to create and edit spreadsheets online, while ... More
Towards Quantifying Non-Local Information Transfer: Finite-Bit Non-LocalityFeb 03 1999May 04 1999The advent of Bell's inequalities provoked the possibility that entangled quantum phenomena is non-local in nature. Since teleportation only requires a finite amount of classical information, i.e. two bits, the author asks whether or not it is possible ... More
A note on the automorphism group of the root lattice of the U-dual modular groupSep 30 2010We study the inclusion system of the quantum deformed 2 dimensional Yang- Mills root module to the graded root module of the U-dual modular group. The irreducible representation of the U-dual modular group is the quantum deformed black brane throat. We ... More
OrientalsJan 16 2006Jul 02 2007The orientals or oriented simplexes are a family of strict omega-categories constructed by Ross Street. We show that the category of orientals is isomorphic to a subcategory of the category of chain complexes. This leads to a very simple combinatorial ... More
Photospheric processes and magnetic flux tubesSep 01 2007In the first part of these lecture notes, new high-resolution observations of small-scale magnetic flux concentrations are presented and compared to results from new three-dimensional magnetohydrodynamic simulations. Special attention is paid to the physics ... More
Recent progresses in the simulation of small-scale magnetic fieldsMay 13 2007New high-resolution observations reveal that small-scale magnetic flux concentrations have a delicate substructure on a spatial scale of 0.1''. Its basic structure can be interpreted in terms of a magnetic flux sheet or tube that vertically extends through ... More
The algebraic structure of the universal complicial setsSep 17 2010May 09 2012The nerve of a strict omega-category is a simplicial set with additional structure, making it into a so-called complicial set, and strict omega-categories are in fact equivalent to complicial sets. The nerve functor is represented by a sequence of strict ... More
Opetopes and chain complexesApr 30 2012Sep 21 2012We give a simple algebraic description of opetopes in terms of chain complexes, and we show how this description is related to combinatorial descriptions in terms of treelike structures. More generally, we show that the chain complexes associated to higher ... 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
Classification of Solvable Feynman Path IntegralsFeb 13 1993A systematic classification of Feynman path integrals in quantum mechanics is presented and a table of solvable path integrals is given which reflects the progress made during the last ten years or so, including, of course, the main contributions since ... More
Quintessence and the Curvature of the Universe after WMAPFeb 13 2003Jun 06 2003We study quintessence models with a constant (effective) equation of state. It is investigated whether such quintessence models are consistent with a negative spatial curvature of the Universe with respect to the anisotropy of the cosmic microwave background ... More
Quintessence with a constant equation of state in hyperbolic universesDec 20 2002Quintessence models leading to a constant equation of state are studied in hyperbolic universes. General properties of the quintessence potentials V(phi) are discussed, and for some special cases also the exact analytic expressions for these potentials ... More
Dark Energy in a Hyperbolic UniverseSep 18 2001May 24 2002Dark energy models due to a slowly evolving scalar (quintessence) field $\phi$ are studied for various potentials $V(\phi)$ in a universe with negative curvature. The potentials differ in whether they possess a minimum at $\phi=0$ or are monotonically ... More
Initial condition from the action principle and its application to cosmology and to false vacuum bubblesApr 25 2013May 02 2013We study models where the gauge coupling constants, masses, etc are functions of some conserved charge in the universe. We first consider the standard Dirac action, but where the mass and the electromagnetic coupling constant are a function of the charge ... More
A KMS-like state of Hadamard type on Robertson-Walker spacetimes and its time evolutionSep 09 1997In this work we define a new state on the Weyl algebra of the free massive scalar Klein-Gordon field on a Robertson-Walker spacetime and prove that it is a Hadamard state. The state is supposed to approximate a thermal equilibrium state on a Robertson-Walker ... More
A solvability criterion for the Lie algebra of derivations of a fat pointSep 08 2009We consider the Lie algebra of derivations of a zero dimensional local complex algebra. We describe an inequality involving the embedding dimension, the order, and the first deviation that forces this Lie algebra to be solvable. Our result was motivated ... More
A normal form algorithm for the Brieskorn latticeAug 21 2001Aug 15 2004This article describes a normal form algorithm for the Brieskorn lattice of an isolated hypersurface singularity. It is the basis of efficient algorithms to compute the Bernstein-Sato polynomial, the complex monodromy, and Hodge-theoretic invariants of ... More
Modeling of magnitude distributions by the generalized truncated exponential distributionMay 22 2014Sep 08 2014The probability distribution of the magnitude can be modeled by an exponential distribution according to the Gutenberg-Richter relation. Two alternatives are the truncated exponential distribution (TED) and the cut-off exponential distribution (CED). ... More
Metric Symplectic Lie AlgebrasSep 12 2016Every metric symplectic Lie algebra has the structure of a quadratic extension. We give a standard model and describe the equivalence classes on the level of corresponding quadratic cohomology sets. Finally, we give a scheme to classify the isomorphism ... More
Symplectic Lie algebras with degenerate centerSep 12 2016Every symplectic Lie algebra with degenerate (including non-abelian nilpotent symplectic Lie algebras) has the structure of a quadratic extension. We give a standard model and describe the equivalence classes on the level of corresponding quadratic cohomology ... More
On contact tops and integrable topsJun 21 2007In this paper, we introduce a geometric structure called top, which is a trivialized bundle of plane pencils over a Riemannian 3-manifold, defined as the set of kernels of a circle of 1-forms (e.g. of contact and integrable forms) with particular properties ... More
Cyclic Cohomology and Higher Rank LatticesDec 01 2006Jun 18 2007We give a new proof of the absence of non-trivial idempotents in the group ring of torsion-free cocompact lattices in SL(n,C). It is based on the following procedure. We lift the class of the trace in the cyclic cohomology of the group ring to the crossed ... More
Exit spaces for Cox processes and the Pólya sum processJun 19 2013For Cox processes we construct a Markov process with increasing paths to couple the condensations of the Cox process in a monotone way. A similar procedure procedure yields an analogue Markov process for the P\'olya sum process. Moreover, we identify ... More
Effective Vinogradov's mean value theorem via efficient boxingMar 08 2016We combine Wooley's efficient congruencing method with earlier work of Vinogradov and Hua to get effective bounds on Vinogradov's mean value theorem.
Quantum Cosmology Close to the Classical Big Bang Singularity and in the Semiclassical LimitJan 28 2010We investigate a cosmological model whose energy content is described by a Chaplygin gas represented by a scalar field $\phi$ with an associated potential producing a big bang singularity such that for vanishing scale factor, $a\to 0$, one has $|\phi|\to ... More
The Cosmic Microwave Background for a Nearly Flat Compact Hyperbolic UniverseJul 18 2000Oct 06 2000The fluctuations of the cosmic microwave background (CMB) are investigated for a hyperbolic universe with finite volume. Four-component models with radiation, matter, vacuum energy, and an extra spatially constant dark energy X-component are considered. ... More
Near Counterexamples to Weil's Converse TheoremJun 22 2016We show that in Weil's converse theorem the functional equations of multiplicative twists for at least the first $\sqrt{\frac{p-24}{3}}$ moduli are needed in order to prove the modularity for $\Gamma_0(p)$.
Timestep control for weakly instationary flowsApr 17 2014May 21 2014We report on recent work on adaptive timestep control for weakly instationary gas flows [16, 18, 17] carried out within SFB 401, TPA3. The method which we implement and extend is a space-time splitting of adjoint error representations for target functionals ... More
Mach like principle from conserved chargesJan 25 2012We study models where the gauge coupling constants, masses and the gravitational constant are functions of some conserved charge in the universe, and furthermore a cosmological constant that depends on the total charge of the universe. We first consider ... More
The Berry-Keating operator on $L^2(\rz_>,\ud x)$ and on compact quantum graphs with general self-adjoint realizationsDec 16 2009May 09 2011The Berry-Keating operator $H_{\mathrm{BK}}:= -\ui\hbar(x\frac{\ud\phantom{x}}{\ud x}+{1/2})$ [M. V. Berry and J. P. Keating, SIAM Rev. 41 (1999) 236] governing the Schr\"odinger dynamics is discussed in the Hilbert space $L^2(\rz_>,\ud x)$ and on compact ... More
Effective Vinogradov's mean value theorem via efficient boxingMar 08 2016Jul 28 2017We combine Wooley's efficient congruencing method with earlier work of Vinogradov and Hua to get effective bounds on Vinogradov's mean value theorem.
Deep Crustal Heating in a Multicomponent Accreted Neutron Star CrustFeb 15 2012May 16 2012A quasi-statistical equilibrium model is constructed to simulate the multicomponent composition of the crust of an accreting neutron star. The ashes of rp-process nucleosynthesis are driven by accretion through a series of electron captures, neutron emissions, ... More
The High-Density Symmetry Energy and Direct UrcaJul 18 2006The symmetry energy of nucleonic matter is usually assumed to be quadratic in the isospin density. While this may be justified at sub-saturation densities, there is no need to enforce this restriction at super-saturation densities. The presence of a quartic ... More
Tilings for Pisot beta numerationOct 04 2013For a (non-unit) Pisot number $\beta$, several collections of tiles are associated with $\beta$-numeration. This includes an aperiodic and a periodic one made of Rauzy fractals, a periodic one induced by the natural extension of the $\beta$-transformation ... More
The Star Dichromatic NumberSep 01 2018Sep 09 2018We introduce a new notion of circular colourings for digraphs. The idea of this quantity, called star dichromatic number $\vec{\chi}^\ast(D)$ of a digraph $D$, is to allow a finer subdivision of digraphs with the same dichromatic number into such which ... More
Progress in animation of an EMA-controlled tongue model for acoustic-visual speech synthesisJan 19 2012We present a technique for the animation of a 3D kinematic tongue model, one component of the talking head of an acoustic-visual (AV) speech synthesizer. The skeletal animation approach is adapted to make use of a deformable rig controlled by tongue motion ... More
Uniform bounds on sup-norms of holomorphic forms of real weightJun 11 2014We establish uniform bounds for the sup-norms of modular forms of arbitrary real weight $k$ with respect to a finite index subgroup $\Gamma$ of $\mathrm{SL}_2(\mathbb{Z})$. We also prove corresponding bounds for the supremum over a compact set. We achieve ... More
Correlations of Quantum Fields on Robertson-Walker SpacetimesNov 09 1995It is a well known fact that quantum fields on Minkowski spacetime are correlated for each pair of spacetime regions. In Robertson-Walker spacetimes there are spacelike separated regions with disjoint past horizons but the absence of correlations in that ... More
On the deformability of Heisenberg algebrasAug 24 1995Based on the vanishing of the second Hochschild cohomology group of the enveloping algebra of the Heisenberg algebra it is shown that differential algebras coming from quantum groups do not provide a non-trivial deformation of quantum mechanics. For the ... More
B-L-symmetric Baryogenesis with Leptonic QuintessenceDec 12 2006We discuss a toy model where baryogenesis and cosmic acceleration are driven by a leptonic quintessence field coupled to the standard model sector via a massive mediating scalar field. It does not require the introduction of B-L-violating interactions ... More
Recent developments in quarkonium and open flavour production calculationsSep 08 2011This report reviews recent theory progress in the field of heavy quarkonium and open heavy flavour production calculations.
Arithmetic Progressions in Abundance by Combinatorial ToolsSep 10 2008Using the algebraic structure of the Stone-Cech compactification of the integers, Furstenberg and Glasner proved that for arbitrary k, every piecewise syndetic set contains a piecewise syndetic set of k-term arithmetic progressions. We present a purely ... More
On infinitely divisible distributions with polynomially decaying characteristic functionsMay 14 2014Jul 09 2014We provide necessary and sufficient conditions on the characteristics of an infinitely divisible distribution under which its characteristic function $\phi$ decays polynomially. Under a mild regularity condition this polynomial decay is equivalent to ... More
General thinning characterizations of distributions and point processesApr 25 2017For general thinning procedures, its inverse operation, the condensing, is studied and a link to integration-by-parts formulas is established. This extends the recent results on that link for independent thinnings of point processes to general thinnings ... More
Performance comparison between iSCSI and other hardware and software solutionsMay 30 2003We report on our investigations on some technologies that can be used to build disk servers and networks of disk servers using commodity hardware and software solutions. It focuses on the performance that can be achieved by these systems and gives measured ... More
Quantum Corrections in Quintessence ModelsJun 12 2006Sep 12 2006We investigate the impact of quantum fluctuations on a light rolling quintessence field from three different sources, namely, from a coupling to the standard model and dark matter, from its self-couplings and from its coupling to gravity. We derive bounds ... More
Sur la rigidité de polyèdres hyperboliques en dimension 3 : cas de volume fini, cas hyperidéal, cas fuchsienNov 18 2002A hyperbolic semi-ideal polyedron is a polyedron whose vertices lie inside the hyperbolic space $\mathbf{H}^{3}$ or at infinity. A hyperideal polyedron is, in the projective model, the intersection of $\mathbf{H}^{3}$ with a projective polyhedron whose ... More
Replica-deformation of the SU(2)-invariant Thirring model via solutions of the qKZ equationJul 17 1999The response of an integrable QFT under variation of the Unruh temperature has recently been shown to be computable from an S-matrix preserving (`replica') deformation of the form factor approach. We show that replica-deformed form factors of the SU(2)-invariant ... More
Polynomial Recursion Equations in Form Factors of ADE Toda Field TheoriesMay 20 1997It is shown that the problem of calculating form factors in ADE affine Toda field theories can be reduced to the nonperturbative recursive calculation of polynomials symmetric in each sort of variables. We determine these recursion equations explicitly ... More
Selfdual 2-form formulation of gravity and classification of energy-momentum tensorsApr 17 1995Dec 17 1996It is shown how the different irreducibility classes of the energy-momentum tensor allow for a Lagrangian formulation of the gravity-matter system using a selfdual 2-form as a basic variable. It is pointed out what kind of difficulties arise when attempting ... More
Likelihood ratio tests and singularitiesMar 12 2007Apr 02 2009Many statistical hypotheses can be formulated in terms of polynomial equalities and inequalities in the unknown parameters and thus correspond to semi-algebraic subsets of the parameter space. We consider large sample asymptotics for the likelihood ratio ... More
A $N$-uniform quantitative Tanaka's theorem for the conservative Kac's $N$-particle system with Maxwell moleculesJul 08 2014Aug 03 2014This paper considers the space homogenous Boltzmann equation with Maxwell molecules and arbitrary angular distribution. Following Kac's program, emphasis is laid on the the associated conservative Kac's stochastic $N$-particle system, a Markov process ... More
Bayesian inverse problems with unknown operatorsJan 30 2018Apr 06 2018We consider the Bayesian approach to linear inverse problems when the underlying operator depends on an unknown parameter. Allowing for finite dimensional as well as infinite dimensional parameters, the theory covers several models with different levels ... More
On the cup product for Hilbert schemes of points in the planeJul 31 2014We revisit Ellingsrud and Str{\o} mme's cellular decomposition of the Hilbert scheme of points in the projective plane. We study the product of cohomology classes defined by the closures of cells, deriving necessary conditions for the non-vanishing of ... More
A determinant-like formula for the Kostka numbersJan 10 2005Sep 01 2005Young tableaux are ubiquitous in various branches of mathematics. There are two counting formulas for standard Young tableaux. The first involves a determinant and goes back to Frobenius and Young, and the second is the hook formula by Frame, Robinson ... More
The Pólya sum kernel and Bayes estimationFeb 21 2012May 10 2012We consider a particular Cox process from a Bayesian viewpoint and show that the Bayes estimator of the intensity measure is the so-called P\'olya sum kernel, which occurred recently in the context of the construction of the so-called Papangelou processes. ... More
The Neutron Star Crust: Nuclear Physics InputNov 12 2007A fully self-consistent model of the neutron star inner crust based upon models of the nucleonic equation of state at zero temperature is constructed. The results nearly match those of previous calculations of the inner crust given the same input equation ... More
Near Counterexamples to Weil's Converse TheoremJun 22 2016Jan 23 2017We show that in Weil's converse theorem the functional equations of multiplicative twists for at least the first $\sqrt{\frac{p-24}{3}}$ moduli are needed in order to prove the modularity for $\Gamma_0(p)$.
Design of Robust, Protograph Based LDPC Codes for Rate-Adaptation via Probabilistic ShapingJul 01 2016In this work, the design of robust, protograph-based low-density parity-check (LDPC) codes for rate-adaptive communication via probabilistic shaping is considered. Recently, probabilistic amplitude shaping (PAS) by B\"ocherer et al. has been introduced ... More
Artimate: an articulatory animation framework for audiovisual speech synthesisMar 15 2012We present a modular framework for articulatory animation synthesis using speech motion capture data obtained with electromagnetic articulography (EMA). Adapting a skeletal animation approach, the articulatory motion data is applied to a three-dimensional ... More
Discrete chain graph modelsSep 04 2009The statistical literature discusses different types of Markov properties for chain graphs that lead to four possible classes of chain graph Markov models. The different models are rather well understood when the observations are continuous and multivariate ... More
Multiple solutions to the likelihood equations in the Behrens-Fisher problemMay 31 2007The Behrens-Fisher problem concerns testing the equality of the means of two normal populations with possibly different variances. The null hypothesis in this problem induces a statistical model for which the likelihood function may have more than one ... More
Logarithmic Comparison Theorem and Euler homogeneity for free divisorsNov 27 2003Aug 18 2004This paper has been withdrawn by the author since the proof of Lemma 8 is not correct.
Calibration of self-decomposable Lévy modelsNov 04 2011Feb 04 2014We study the nonparametric calibration of exponential L\'{e}vy models with infinite jump activity. In particular our analysis applies to self-decomposable processes whose jump density can be characterized by the $k$-function, which is typically nonsmooth ... More
The Pólya sum process: Limit theorems for conditioned random fieldsJan 20 2012In \cite{hZ09}, Zessin constructed the so-called P\'olya sum process via partial integration technique. This process shares some important properties with the Poisson process such as complete randomness and infinite divisibility. This work discusses H-sufficient ... More
Good bases for tame polynomialsJun 06 2003Dec 01 2004An algorithm to compute a good basis of the Brieskorn lattice of a cohomologically tame polynomial is described. This algorithm is based on the results of C. Sabbah and generalizes the algorithm by A. Douai for convenient Newton non-degenerate polynomials. ... More
The differential structure of the Brieskorn latticeJun 05 2003Dec 01 2004We describe an algorithm to compute M. Saito's matrices A0 and A1 for an isolated hypersurface singularity. They determine the differential structure of the Brieskorn lattice, the spectral pairs and Hodge numbers, and the complex monodromy of the singularity. ... More
On Alternation and the Union TheoremFeb 15 2016Jun 03 2016Under the assumption $P=\Sigma_2^p$, we prove a new variant of the Union Theorem of McCreight and Meyer for the class $\Sigma_2^p$. This yields a union function $F$ which is computable in time $F(n)^c$ for some constant $c$ and satisfies $P=DTIME(F)=\Sigma_2(F)=\Sigma_2^p$ ... More
A Nekrasov-Okounkov type formula for type CMay 06 2015In 2008, Han rediscovered an expansion of powers of Dedekind $\eta$ function due to Nekrasov and Okounkov by using Macdonald's identity in type $\widetilde{A}$. In this paper, we obtain new combinatorial expansions of powers of $\eta$, in terms of partition ... More
Approximations for Decision Making in the Dempster-Shafer Theory of EvidenceFeb 13 2013The computational complexity of reasoning within the Dempster-Shafer theory of evidence is one of the main points of criticism this formalism has to face. To overcome this difficulty various approximation algorithms have been suggested that aim at reducing ... More
On a probabilistic interpretation of shape derivatives of Dirichlet groundstates with application to Fermion nodesJan 28 2013This paper considers Schr\"odinger operators, and presents a probabilistic interpretation of the variation (or shape derivative) of the Dirichlet groundstate energy when the associated domain is perturbed. This interpretation relies on the distribution ... More
Open Subtitles Paraphrase Corpus for Six LanguagesSep 17 2018This paper accompanies the release of Opusparcus, a new paraphrase corpus for six European languages: German, English, Finnish, French, Russian, and Swedish. The corpus consists of paraphrases, that is, pairs of sentences in the same language that mean ... More
Solving Kepler's equation CORDIC-likeAug 21 2018Nov 19 2018Context. Many algorithms to solve Kepler's equations require the evaluation of trigonometric or root functions. Aims. We present an algorithm to compute the eccentric anomaly and even its cosine and sine terms without usage of other transcendental functions ... More
Dark Matter from Freeze-In via the Neutrino PortalJun 22 2018May 03 2019We investigate a minimal neutrino portal dark matter (DM) model where a right-handed neutrino both generates the observed neutrino masses and mediates between the SM and the dark sector, which consists of a fermion and a boson. In contrast to earlier ... More
Linear-Time Tree Containment in Phylogenetic NetworksFeb 21 2017We consider the NP-hard Tree Containment problem that has important applications in phylogenetics. The problem asks if a given leaf-labeled network contains a subdivision of a given leaf-labeled tree. We develop a fast algorithm for the case that the ... More
Estimation of integrated volatility of volatility with applications to goodness-of-fit testingJun 25 2012Sep 29 2015In this paper, we are concerned with nonparametric inference on the volatility of volatility process in stochastic volatility models. We construct several estimators for its integrated version in a high-frequency setting, all based on increments of spot ... More
Extremal results for random discrete structuresMar 02 2016May 17 2016We study thresholds for extremal properties of random discrete structures. We determine the threshold for Szemer\'edi's theorem on arithmetic progressions in random subsets of the integers and its multidimensional extensions and we determine the threshold ... More
Form Factors in $D_n^{(1)}$ Affine Toda Field TheoriesDec 12 1996May 02 1997We derive closed recursion equations for the symmetric polynomials occuring in the form factors of $D_n^{(1)}$ affine Toda field theories. These equations follow from kinematical- and bound state residue equations for the full form factor. We also discuss ... More
q-Deformed Relativistic Wave EquationsOct 15 1993Based on the representation theory of the $q$-deformed Lorentz and Poincar\'e symmeties $q$-deformed relativistic wave equation are constructed. The most important cases of the Dirac-, Proca-, Rarita-Schwinger- and Maxwell- equations are treated explicitly. ... More
Algebraic Techniques for Gaussian ModelsOct 23 2006Many statistical models are algebraic in that they are defined by polynomial constraints or by parameterizations that are polynomial or rational maps. This opens the door for tools from computational algebraic geometry. These tools can be employed to ... More
An ultrafilter approach to Jin's TheoremAug 20 2009It is well known and not difficult to prove that if $C$ of integers has positive upper Banach density, the set of differences $C-C$ is syndetic, i.e. the length of gaps is uniformly bounded. More surprisingly, Renling Jin showed that whenever $A$ and ... More
The Turing Test for TelepresenceNov 09 2015The quality of high-end videoconferencing systems has improved significantly over the last few years enabling a class of applications known as "telepresence" wherein the users engaged in a communication session experience a feeling of mutual presence ... More
A novel model and estimation method for the individual random component of earthquake ground-motion relationsNov 06 2015Mar 15 2016In this paper, I introduce a novel approach to modelling the individual random component (also called the intra-event uncertainty) of a ground-motion relation (GMR), as well as a novel approach to estimating the corresponding parameters. In essence, I ... More
Markov Chains on Orbits of Permutation GroupsAug 09 2014We present a novel approach to detecting and utilizing symmetries in probabilistic graphical models with two main contributions. First, we present a scalable approach to computing generating sets of permutation groups representing the symmetries of graphical ... More
Using ZDDs in the mapping of quantum circuitsJan 08 2019In quantum compilation, one step translates a technology-independent quantum circuit into a technology-dependent quantum circuit for a targeted device. Besides mapping quantum gates into the supported gate set, it is necessary to map pseudo qubits in ... More
Hoppe trees, random recursive sets and their barycentreJul 06 2012We consider a recursively defined random set of points and its barycenter, where the random set is constructed by the following inductive rule: Given a realization of $n-1$ points, one of them is picked at random and serves as a source the $n$-th point. ... More
Characterization of Cyclically Fully commutative elements in finite and affine Coxeter GroupsMar 05 2014Oct 02 2014An element of a Coxeter group W is fully commutative if any two of its reduced decompositions are related by a series of transpositions of adjacent commuting generators. An element of a Coxeter group W is cyclically fully commutative if any of its cyclic ... More
On Saito's normal crossing conditionNov 15 2013Sep 23 2016Kyoji Saito defined a residue map from the logarithmic differential 1-forms along a reduced complex analytic hypersurface to the meromorphic functions on the hypersurface. He studied the condition that the image of this map coincides with the weakly holomorphic ... More
Equivariant K-homology of Bianchi groups with non-trivial class groupJan 06 2013May 13 2013We compute the equivariant K-homology of the groups PSL_2 of imaginary quadratic integers with trivial and non-trivial class-group. This was done before only for cases of trivial class number. We rely on reduction theory in the form of the $\Gamma$-CW-complex ... More
Probing Pauli Blocking Factors in Quantum Pumps with Broken Time-Reversal SymmetryJun 21 2000A recently demonstrated quantum electron pump is discussed within the framework of photon-assisted tunneling. Due to lack of time-reversal symmetry, different results are obtained for the pump current depending on whether or not final-state Pauli blocking ... More
A criterion for the logarithmic differential operators to be generated by vector fieldsJun 01 2004Aug 30 2006We study divisors in a complex manifold in view of the property that the algebra of logarithmic differential operators along the divisor is generated by logarithmic vector fields. We give a sufficient criterion for the property, a simple proof of F.J. ... More
Monodromy of Hypersurface SingularitiesAug 21 2001Dec 01 2004We describe algorithmic methods for the Gauss-Manin connection of an isolated hypersurface singularity based on the microlocal structure of the Brieskorn lattice. They lead to algorithms for computing invariants like the monodromy, the spectrum, and the ... More