Results for "Jan Kuneš"

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Improved Green's Function Measurement for Hybridization Expansion Quantum Monte CarloFeb 19 2013We present an algorithm for measurement of the Green's function in the hybridization expansion continuous-time quantum Monte-Carlo based on continuous estimators. Compared to the standard method, the present algorithm has similar or better accuracy with ... More
Suppression and revival of long-range ferromagnetic order in the multiorbital Fermi-Hubbard modelFeb 08 2018By means of dynamical mean-field theory allowing for complete account of SU(2) rotational symmetry of interactions between spin-1/2 particles, we observe a strong effect of suppression of ferromagnetic order in the multiorbital Fermi-Hubbard model in ... More
Doping dependence of spin fluctuations and electron correlations in iron pnictidesFeb 24 2010Jul 20 2010Doping dependence of the spin fluctuations and the electron correlations in the effective five-band Hubbard model for iron pnictides is investigated using the fluctuation-exchange approximation. For a moderate hole doping, we find a dominant low-energy ... More
Phase diagram and Gap anisotropy in Iron-Pnictide SuperconductorsDec 10 2009Feb 24 2010Using the fluctuation-exchange (FLEX) approximation we study an effective five-band Hubbard model for iron-pnictide superconductors obtained from the first-principles band structure. We preclude deformations of the Fermi surface due to electronic correlations ... More
Continuum Charge Excitations in High-Valence Transition-Metal Oxides Revealed by Resonant Inelastic X-ray ScatteringMar 10 2018Sep 13 2018We present a theoretical investigation of the origin of Raman-like and fluorescencelike (FL) features of resonant inelastic x-ray scattering (RIXS) spectra. Using a combination of local-density approximation + dynamical mean-field theory and a configuration ... More
Numerical calculation of spectral functions of the Bose-Hubbard model using B-DMFTMar 17 2015Apr 08 2015We calculate the momentum dependent spectral function of the Bose-Hubbard model on a simple cubic lattice in three dimensions within the bosonic dynamical mean-field theory (B-DMFT). The continuous-time quantum Monte Carlo method is used to solve the ... More
Antiferromagnetism in RuO$_2$ as $d$-wave Pomeranchuk instabilityFeb 12 2019We present a computational study of antiferromagnetic transition in RuO$_2$. The rutile structure with the magnetic sublattices coupled by $\pi/2$-rotation leads to a spin-polarized band structure in the antiferromagnetic state, which gives rise to a ... More
Pressure-induced spin-state ordering in Sr$_2$CoO$_3$FFeb 18 2019We study theoretically low-temperature phases of a recently-synthesized compound Sr$_2$CoO$_3$F under pressure. The analysis combining LDA+DMFT and strong-coupling effective model points to the existence of not only normal paramagnetic and antiferromagnetic ... More
Low-temperature properties of single-crystal CrB$_{2}$Dec 04 2014We report the low-temperature properties of $^{11}$B-enriched single-crystal CrB$_{2}$ as prepared from high-purity Cr and B powder by a solid-state reaction and optical float zoning. The electrical resistivity, $\rho_{\rm xx}$, Hall effect, $\rho_{\rm ... More
Hard x-ray 1$s$ photoemission spectroscopy as a probe of charge transfer in late transition metal oxidesDec 16 2018We study $1s$ and $2p$ hard x-ray photoemission spectra (XPS) in a series of late transition metal oxides: Fe$_2$O$_3$ (3$d^{5}$), FeTiO$_3$ (3$d^{6}$), CoO (3$d^{7}$) and NiO (3$d^{8}$). The experimental spectra are analyzed with two theoretical approaches: ... More
Excitonic dispersion of the intermediate-spin state in LaCoO$_3$ revealed by resonant inelastic X-ray scatteringDec 13 2017Aug 07 2018More than 50 years ago the electron-hole attraction was proposed to drive narrow gap semiconductors or semimetals to a new phase, the excitonic insulator. The experimental proof of its existence in bulk materials remains elusive. In strongly correlated ... More
Crystal field of rare earth impurities in LaF$_3$Jul 29 2014The crystal field parameters of 13 trivalent lanthanide ions substituted for La in LaF$_3$ were calculated using the combination of the band structure and Wannier function calculations. Performing an atomic exact diagonalization with thus obtained crystal-field ... More
Singular compactness and definability for $Σ$-cotorsion and Gorenstein modulesApr 24 2018May 25 2018We introduce a general version of singular compactness theorem which makes it possible to show that being a $\Sigma$-cotorsion module is a property of the complete theory of the module. As an application of the powerful tools developed along the way, ... More
The countable Telescope Conjecture for module categoriesJan 25 2008May 16 2008By the Telescope Conjecture for Module Categories, we mean the following claim: "Let R be any ring and (A, B) be a hereditary cotorsion pair in Mod-R with A and B closed under direct limits. Then (A, B) is of finite type." We prove a modification of this ... More
Magnetic state and electronic structure of plutonium from ``first principles'' calculationsOct 30 2006The goal to describe plutonium phases from ``first principles'' calculation methods is complicated by the problem of 5f-electrons localization. While for early actinides (Th, U,Np) standard DFT (Density Functional Theory) description with itinerant 5f-electrons ... More
Neutral Kaon Mixing Beyond the Standard Model from 2+1 Flavour Domain Wall QCDOct 10 2008We present preliminary results of a study of Delta S = 2 matrix elements originating from physics beyond the Standard Model. Using 2+1 flavour Domain Wall Fermions we obtain the non-perturbative renormalisation (mixing) matrix in the RI scheme. We also ... More
Fine-tune your smile: Correction to Hagan et alAug 07 2007Mar 18 2008In this small note we use results derived in Berestycki et al. to correct the celebrated formulae of Hagan et al. We derive explicitly the correct zero order term in the expansion of the implied volatility in time to maturity. The new term is consistent ... More
Fullerenes in circumstellar and interstellar environmentsOct 05 2012In recent years, the fullerene species C60 (and to a lesser extent also C70) has been reported in the mid-IR spectra of various astronomical objects. Cosmic fullerenes form in the circumstellar material of evolved stars, and survive in the interstellar ... More
Polynomial Homotopies for Dense, Sparse and Determinantal SystemsJul 12 1999Numerical homotopy continuation methods for three classes of polynomial systems are presented. For a generic instance of the class, every path leads to a solution and the homotopy is optimal. The counting of the roots mirrors the resolution of a generic ... More
Modernizing PHCpack through phcpySep 30 2013Apr 29 2014PHCpack is a large software package for solving systems of polynomial equations. The executable phc is menu driven and file oriented. This paper describes the development of phcpy, a Python interface to PHCpack. Instead of navigating through menus, users ... More
Noetherianity up to symmetryOct 07 2013Nov 04 2013These lecture notes for the 2013 CIME/CIRM summer school Combinatorial Algebraic Geometry deal with manifestly infinite-dimensional algebraic varieties with large symmetry groups. So large, in fact, that subvarieties stable under those symmetry groups ... More
Fundamental solutions of evolutionary PDOs and rapidly decreasing distributionsMay 04 2011Let $P(\partial_0,\partial_1,...,\partial_n)$ be a PDO on $\symR^{1+n}$ with constant coefficients. It is proved that (i) the real parts of the $\lambda$-roots of the polynomial $P(\lambda,i\xi_1,...,i\xi_n)$ are bounded from above when $(\xi_1,...,\xi_n)$ ... More
Homological stability for certain classical groupsMar 28 2008We prove homological stability for standard unitary groups over R, C and H and for general linear groups over skew-fields with infinite centre. We focus on the similarities and differences of these proofs. Both proofs are due to Chih-Han Sah (Homology ... More
The q-exponential family in statistical physicsSep 27 2008The notion of generalised exponential family is considered in the restricted context of nonextensive statistical physics. Examples are given of models belonging to this family. In particular, the q-Gaussians are discussed and it is shown that the configurational ... More
Non-unique way to generalize the Boltzmann-Gibbs distributionMar 04 2003Alternative definitions are given of basic concepts of generalized thermostatistics. In particular, generalizations of Shannon's entropy, of the Boltzmann-Gibbs distribution, and of relative entropy are considered. Particular choices made in Tsallis' ... More
Generalised exponential families and associated entropy functionsMar 02 2008A generalised notion of exponential families is introduced. It is based on the variational principle, borrowed from statistical physics. It is shown that inequivalent generalised entropy functions lead to distinct generalised exponential families. The ... More
Escort density operators and generalized quantum information measuresJul 30 2004Parametrized families of density operators are studied. A generalization of the lower bound of Cramer and Rao is formulated. It involves escort density operators. The notion of phi-exponential family is introduced. This family, together with its escort, ... More
Solving inverse problems by combination of maximum entropy and montecarlo simulationNov 13 2000The montecarlo method, which is quite commonly used to solve maximum entropy problems in statistical physics, can actually be used to solve inverse problems in a much wider context. The probability distribution which maximizes entropy can be calculated ... More
Quantisation and Gauge InvarianceOct 25 1999Recent developments concerning canonical quantisation and gauge invariant quantum mechanical systems and quantum field theories are briefly discussed. On the one hand, it is shown how diffeomorphic covariant representations of the Heisenberg algebra over ... More
Symmetry Tests of the Electroweak Interaction from Muon Capture on 3HeJan 27 1997Precision measurements in muon capture on 3He to the triton channel provide for interesting tests of the charged electroweak interaction, whether within the Standard Model or beyond it. Based on the statistical capture rate and the triton asymmetry, both ... More
Relativistic Rigid Particles: Classical Tachyons and Quantum AnomaliesJul 31 1992Causal rigid particles whose action includes an {\it arbitrary} dependence on the world-line extrinsic curvature are considered. General classes of solutions are constructed, including {\it causal tachyonic} ones. The Hamiltonian formulation is developed ... More
The Cosmological Constant of One-Dimensional Matter Coupled Quantum Gravity is QuantisedAug 03 2004Coupling any interacting quantum mechanical system to gravity in one (time) dimension requires the cosmological constant to belong to the matter energy spectrum and thus to be quantised, even though the gravity sector is free of any quantum dynamics. ... More
Half-Integer Winding Number Solutions to the Landau-Ginzburg-Higgs Equations and Instability of the Abrikosov-Nielsen-Olesen VortexJul 14 2000New solutions to the abelian U(1) Higgs model, corresponding to vortices of integer and half-integer winding number bound onto the edges of domain walls and possibly surrounded by annular current flows, are described, based on a fine-grained analysis ... More
A Quantum Anomaly For Rigid ParticlesJul 21 1992Jul 23 1992Canonical quantisation of rigid particles is considered paying special attention to the restriction on phase space due to causal propagation. A mixed Lorentz-gravitational anomaly is found in the commutator of Lorentz boosts with world-line reparametrisations. ... More
Image-guided therapy system for interstitial gynecologic brachytherapy in a multimodality operating suiteSep 22 2013In this contribution, an image-guided therapy system supporting gynecologic radiation therapy is introduced. The overall workflow of the presented system starts with the arrival of the patient and ends with follow-up examinations by imaging and a superimposed ... More
Nonparametric estimation in functional linear models with second order stationary regressorsJan 27 2009We consider the problem of estimating the slope parameter in functional linear regression, where scalar responses Y1,...,Yn are modeled in dependence of second order stationary random functions X1,...,Xn. An orthogonal series estimator of the functional ... More
Efficient treatment of two-particle vertices in dynamical mean-field theoryOct 19 2010Jan 17 2011We present an efficient and numerically stable algorithm for calculation of two-particle response functions within the dynamical mean-field theory. The technique is based on inferring the high frequency asymptotic behavior of the irreducible vertex function ... More
Modelling the light-curve of KIC 12557548b: an extrasolar planet with a comet like tailAug 17 2012May 09 2013An object with a very peculiar light-curve was discovered recently using Kepler data. Authors argue that this object may be a transiting disintegrating planet with a comet like dusty tail. We calculate the light-curves of stars with such planets and take ... More
Plurifine Potential TheoryJul 03 2012An overview of the recent developments in plurifine potential theory.
Transitive Lie algebras of vector fields---an overviewJul 14 2011Aug 18 2011This overview paper is intended as a quick introduction to Lie algebras of vector fields. Originally introduced in the late 19th century by Sophus Lie to capture symmetries of ordinary differential equations, these algebras, or infinitesimal groups, are ... More
Puiseux series dynamics of Quadratic rational mapsMay 31 2011We give a complete description for the dynamics of quadratic rational maps with coefficients in the completion of the field of formal Puiseux series.
Rational rays and critical portraits of complex polynomialsOct 15 1997The aim of this work is to describe the equivalence relations in $\Q/\Z$ that arise as the rational lamination of polynomials with all cycles repelling. We also describe where in parameter space one can find a polynomial with all cycles repelling and ... More
Theoretical and phenomenological aspects of G$χ$PTOct 07 1997Consequences of the alternative mechanism of spontaneous breaking of chiral symmetry without formation of a large quark antiquark condensate is reviewed. Emphasis is put on the resulting picture of light quark masses.
Flow-Force Compensation in a Hydraulic ValveApr 28 2015Flow-reaction forces acting in hydraulic valves have been studied for many decades. Despite this, they are difficult to account for due to the complexities of the jet flow. This paper focuses only on the reduction, also referred to as compensation, of ... More
Jacob's ladders and $|ζ|^{-2}$-representation of some functionals generated by a new class of transcendental integralsSep 26 2013In this paper we introduce a new infinite set of transcendental integrals. Each of them is expressed by corresponding value of the function $|\zf|^{-2}$. Such a property is another argument about universality of the Riemann zeta-function $\zf$ in the ... More
On the roots of the equation $Z'(t)=0$Mar 05 2013We have proved in this paper that the Lindel\" of hypothesis generates essential contraction of distances between consecutive odd-order zeros of the function $Z'(t)$. This paper is the translation of the paper \cite{11} into the English except part 8 ... More
Riemann hypothesis and some new integrals connected with the integral negativity of the remainder in the formula for the prime-counting function $π(x)$May 25 2011In this paper a new integral for the remainder of $\pi(x)$ is obtained. It is proved that there is an infinite set of the formulae containing miscellaneous parts of this integral.
Jacob's ladders and the nonlocal interaction of the function $Z(t)$ with the function $\tilde{Z}^2(t)$ on the distance $\sim (1-c)π(t)$ for a collection of disconnected setsJun 26 2010Jul 19 2010It is shown in this paper that there is a fine correlation of the third order between the values of the functions $Z[\vp_1(t)]$ and $\tilde{Z}^2(t)$ which corresponds to two collections of disconnected sets. The corresponding new asymptotic formula cannot ... More
Jacob's ladders, Riemann's oscillators, quotient of two oscillating multiforms and set of metamorphoses of this systemJun 01 2015In this paper we introduce complicated oscillating system, namely quotient of two multiforms based on Riemann-Siegel formula. We prove that there is an infinite set of metamorphoses of this system (=chrysalis) on critical line $\sigma=\frac 12$ into a ... More
Microscopic interpolation formula for the Riemann $Z(t)$-function and new algorithm for asymptotic solution of some Diophantine equation with Leibnitz coefficientsJan 29 2014In this paper we use the values of the Riemann $Z(t)$-function in order to construct certain quasi-orthonormal system of vectors. On this basis we prove a formula for microscopic interpolation of the function $Z(t)$. Simultaneously we have obtained a ... More
Distribution of the roots of the equations $Z(t)=0$, $Z'(t)=0$ in the theory of the Riemann zeta-functionJul 03 2013Let the symbols $\{\gamma\},\ \{t_0\};\ t_0\not=\gamma$ denote the sequences of the roots of the equations $$Z(t)=0,\quad \text{and}\qquad Z'(t)=0,$$ respectively, and $$m(t_0)=\min\{\gamma"-t_0,t_0-\gamma'\},\quad Q(t_0)=\max\{\gamma"-t_0,t_0-\gamma'\},\quad ... More
Jacob's ladders and new class of integrals containing product of factors $ζ^2$Mar 01 2012In this paper we obtain new properties of a signal generated by the Riemann zeta-function on the critical line. At the same time we obtain an asymptotic formula for a new class of transcendental integrals connected with the Riemann zeta-function.
A minimal integral of the Riemann $Ξ$-functionAug 04 2011Aug 17 2011In this paper we obtain an equilibrium sequence $\{\omega_n\}$ for which the following holds true: the areas (measures) of the figures corresponding to the positive and negative parts, respectively, of the graph of the function $\Xi(t),\ t\in[\omega_n,\omega_{n+1}]$ ... More
Jacob's ladders, the structure of the Hardy-Littlewood integral and some new class of nonlinear integral equationsMar 02 2011In this paper we obtain new formulae for short and microscopic parts of the Hardy-Littlewood integral, and the first asymptotic formula for the sixth order expression $|\zeta(\frac{1}{2}+i\vp_1(t))|^4|\zf|^2$. These formulae cannot be obtained in the ... More
Jacob's ladders and some new consequences from A. Selberg's formulaOct 05 2010It is proved in this paper that the Jacob's ladders together with the A. Selberg's classical formula (1942) lead to a new kind of formulae for some short trigonometric sums. These formulae cannot be obtained in the classical theory of A. Selberg, and ... More
Jacob's ladders and the asymptotically approximate solutions of a nonlinear diophantine equationJan 18 2010The nonlinear equation which is connected with the main term of the Hardy-Littlewood formula for $\zeta^2(1/2+it)$ is studied. In this direction I obtain the fine results which cannot be reached by published methods of Balasubramanian, Heath-Brown and ... More
Heterogeneous bounds of confidence: Meet, Discuss and Find Consensus!Jan 09 2008Aug 13 2009Models of continuous opinion dynamics under bounded confidence show a sharp transition between a consensus and a polarization phase at a critical global bound of confidence. In this paper, heterogeneous bounds of confidence are studied. The surprising ... More
Continuous Opinion Dynamics: Insights through Interactive Markov ChainsAug 24 2007We reformulate the agent-based opinion dynamics models of Weisbuch-Deffuant and Hegselmann-Krause as interactive Markov chains. So we switch the scope from a finite number of n agents to a finite number of n opinion classes. Thus, we will look at an infinite ... More
Convergence of products of stochastic matrices with positive diagonals and the opinion dynamics backgroundAug 23 2007We present a convergence result for infinite products of stochastic matrices with positive diagonals. We regard infinity of the product to the left. Such a product converges partly to a fixed matrix if the minimal positive entry of each matrix does not ... More
Convergence in inhomogeneous consensus processes with positive diagonalsSep 13 2006We present a results about convergence of products of row-stochastic matrices which are infinite to the left and all have positive diagonals. This is regarded as in inhomogeneous consensus process where confidence weights may change in every time step ... More
Deformations of cones over hyperelliptic curvesMar 23 1993We determine the versal deformation of cones, in the simplest case: cones over hyperelliptic curves of high degree. In particular, we show that for degree $4g+4$, the highest degree for which interesting deformations exist, the number of smoothing components ... More
Quantum fields with classical interactionsJul 03 2013May 05 2014We describe basic types of free fields (1) neutral scalar bosons; (2) massive vector bosons; (3) massless vector bosons; (4) charged scalar bosons; (5) Dirac fermions; (6) Majorana fermions. We also consider free field perturbed by a linear or quadratic ... More
Discrete Cucker-Smale's flocking model with a weakly singular weightDec 19 2014For the discrete Cucker-Smale's flocking model with a singular communication weight $\psi(s) = s^{-\alpha}$, with $0<\alpha<1/2$ , we prove that the velocity component of certain type of weak solutions is absolutly continuous. This result enables us to ... More
The boundary action of a sofic random subgroup of the free groupJun 06 2013Nov 26 2014We prove that the boundary action of a sofic random subgroup of a finitely generated free group is conservative. This addresses a question asked by Grigorchuk, Kaimanovich, and Nagnibeda, who studied the boundary actions of individual subgroups of the ... More
High-order behaviour and summation methods in perturbative QCDDec 11 1995After reviewing basic facts about large-order behaviour of perturbation expansions in various fields of physics, I consider several alternatives to the Borel summation method and discuss their relevance to different physical situations. Then I convey ... More
Surfaces with maximal constant mean curvatureDec 20 2007In this note we consider asymptotically flat manifolds with non-negative scalar curvature and an inner boundary which is an outermost minimal surface. We show that there exists an upper bound on the mean curvature of a constant mean curvature surface ... More
Magnetic Skyrmions on a Two-Lane RacetrackJun 23 2016Sep 15 2016Magnetic skyrmions are particle-like textures in the magnetization, characterized by a topological winding number. Nanometer-scale skyrmions have been observed at room temperature in magnetic multilayer structures. The combination of small size, topological ... More
Functional linear instrumental regression under second order stationarityMar 04 2016We consider the problem of estimating the slope parameter in functional linear instrumental regression, where in the presence of an instrument W, i.e., an exogenous random function, a scalar response Y is modeled in dependence of an endogenous random ... More
The super-indeterminism in orthodox quantum mechanics does not implicate the reality of experimenter free willMar 10 2016Mar 21 2016The concept of 'super-indeterminism' captures the notion that the free choice assumption of orthodox quantum mechanics necessitates only the following requirement: an agent's free-choice performance in the selection of measurement settings must not represent ... More
Nonparametric General Reinforcement LearningNov 28 2016Reinforcement learning (RL) problems are often phrased in terms of Markov decision processes (MDPs). In this thesis we go beyond MDPs and consider RL in environments that are non-Markovian, non-ergodic and only partially observable. Our focus is not on ... More
Commissioning of the COBRA demonstrator and investigation of surface events as its main backgroundSep 13 2016The COBRA collaboration investigates 0{\nu}\beta\beta-decays (neutrinoless double beta-decays). Therefore, a demonstrator setup using coplanar-grid CdZnTe detectors is operated at the LNGS underground laboratory. In this work, the demonstrator was commissioned ... More
Trend to equilibrium for a reaction-diffusion system modelling reversible enzyme reactionOct 23 2016A spatio-temporal evolution of chemicals appearing in a reversible enzyme reaction and modelled by a four component reaction-diffusion system with the reaction terms obtained by the law of mass action is considered. The large time behaviour of the system ... More
Exploration PotentialSep 16 2016Nov 18 2016We introduce exploration potential, a quantity that measures how much a reinforcement learning agent has explored its environment class. In contrast to information gain, exploration potential takes the problem's reward structure into account. This leads ... More
Charting the future frontier(s) of particle productionAug 25 2016This short note describes the long collaborative effort between Arizona and Krak\'ow, showing some of the key strangeness signatures of quark-gluon plasma. It further presents an annotated catalog of foundational questions defining the research frontiers ... More
Bosonic quadratic HamiltoniansAug 10 2016We discuss self-adjoint operators given formally by expressions quadratic in bosonic creation and annihilation operators. We give conditions when they can be defined as self-adjoint operators, possibly after an infinite renormalization. We also discuss ... More
On Heron Simplices and Integer EmbeddingDec 21 2001In "Unsolved Problems in Number Theory" problem D22 Richard Guy asked for the existence of simplices with integer lengths, areas, volumes... In dimension two this is well known, these triangles are called Heron triangles. Here I will present my results ... More
Symmetric Graphs have symmetric MatchingsJul 25 2016Assume that there is a free group action of automorphisms on a bipartite graph. If there is a perfect matching on the factor graph, then obviously there is a perfect matching on the graph. Surprisingly, the reversed is also true for amenable groups: if ... More
Stochastic Coupling of FermionsSep 30 1995The stochastic quantization of the fermion field is performed starting from Dirac equations. The statistical properties of stochastic terms in Langevin equations are described by explicit formulae of a Markov process. The interaction of the field is introduced ... More
Randomized feasible interpolation and monotone circuits with a local oracleNov 26 2016We generalize the feasible interpolation theorem for semantic derivations from K.(1997) by allowing randomized protocols (protocols in the sense of K.(1997). We also introduce an extension of the monotone circuit model, monotone circuits with a local ... More
Mahler Measure, Eisenstein Series and DimersFeb 09 2005This note reveals a mysterious link between the partition function of certain dimer models on 2-dimensional tori and the $L$-function of their spectral curves. It also relates the partition function in certain families of dimer models to Eisenstein series. ... More
Searches for Particle Dark Matter with the GLAST Large Area TelescopeJun 06 2007The Large Area Telescope (LAT), one of two instruments on the Gamma-ray Large Area Space Telescope (GLAST) mission, scheduled for launch by NASA in 2007, is an imaging, wide field-of-view, high-energy gamma-ray telescope, covering the approximate energy ... More
Discovery and Upper Limits in Search for Exotic Physics with Neutrino TelescopesDec 04 2006This note gives a short review of the statistical issues concerning upper limit calculation and claiming of discovery arising in the search for exotic physics with neutrino telescopes. Low sample sizes and significant instrumental uncertainties require ... More
On the SPA Convention and ProjectDec 21 2005Reconstruction of the fundamental supersymmetric theory and its breaking mechanism will require high-precision tools. Here a brief introduction to SPA, the Supersymmetry Parameter Analysis (SPA) Convention and Project, is presented which is based on a ... More
Supersymmetry Parameter AnalysisDec 30 2002Supersymmetric particles can be produced copiously at future colliders. From the high-precision data taken at e+e- linear colliders, TESLA in particular, and combined with results from LHC, and CLIC later, the low-energy parameters of the supersymmetric ... More
Determining SUSY Parameters from Chargino Pair ProductionMay 31 1999A procedure to determine the chargino mixing angles and, subsequently, the fundamental SUSY parameters M2, mu and tan(beta) by measurements of the total cross section and the spin correlations in e+e- annihilation to chi1^+ chi1^- chargino pairs is discussed. ... More
Sleptons at LEP2 and Tevatron in R-Parity Violating SUSYAug 29 1997In supersymmetric theories with R-parity breaking, sleptons could be produced singly in $e^+e^-$ collisions at LEP2 and in $q\bar{q}$ annihilation at the Tevatron through interactions in which two quark or two lepton fields are coupled to a slepton field. ... More
TESTING THE $WWγ$ COUPLING AT $e^+e^-$ COLLIDERSJan 09 1995The production of single photons plus missing energy at future $e^{+}e^{-}$ colliders can provide a testing ground for non-standard $WW\gamma$ couplings. We show that even with conservative estimates of systematic errors there is still considerable sensitivity ... More
Three-Body Decays of the Susy Higgs BosonsJul 26 1995In this talk I discuss three-body decays of the SUSY Higgs bosons which proceed via intermediate two-body states in which one of the particles is off-mass-shell. Some of these decays will be shown to have substantial branching ratios in some range of ... More
Finding CP-violating HiggsesJun 11 1999In a general two-Higgs-doublet model with CP violation in the Higgs sector, the three neutral physical Higgs bosons have no definite CP properties. A new sum rule relating Yukawa and Higgs-Z couplings implies that a neutral Higgs boson cannot escape detection ... More
Baryon Spectroscopy - Recent Results from the CBELSA/TAPS ExperimentJan 06 2016One of the remaining challenges within the standard model is to gain a good understanding of QCD in the non-perturbative regime. One key step toward this aim is baryon spectroscopy, investigating the spectrum and the properties of baryon resonances. To ... More
Rolling Factors Deformations and Extensions of Canonical CurvesJun 26 2000A tetragonal canonical curve is the complete intersection of two divisors on a scroll. The equations can be written in `rolling factors' format. For such homogeneous ideals we give methods to compute infinitesimal deformations. Deformations can be obstructed. ... More
Classification of invariant AHS--structures on semisimple locally symmetric spacesJan 22 2013In this article, we discuss which semisimple locally symmetric spaces admit an AHS--structure invariant to local symmetries. We classify them for all types of AHS--structures and determine possible equivalence classes of such AHS--structures.
The Bramble-Hilbert LemmaOct 26 2007Oct 28 2007This is an introductory document surveying several results in polynomial approximation, known as the Bramble-Hilbert lemma.
The maximal spectral radius of a digraph with (m+1)^2 - s edgesOct 23 2002Mar 11 2003It is known that the spectral radius of a digraph with k edges is \le \sqrt{k}, and that this inequality is strict except when k is a perfect square. For k=m^2 + \ell, \ell fixed, m large, Friedland showed that the optimal digraph is obtained from the ... More
Homogeneous models of C3 Monge geometriesJun 08 2016Jun 29 2016Distributions of Monge type are a class of strongly regular bracket-generating distributions introduced by I. Anderson, Zh. Nie and P. Nurowski. Their symbol algebras prolong to simple graded Lie algebras, thus allowing one to associate a parabolic geometry ... More
A density result for Sobolev functions and functions of higher order bounded variation with additional integrability constraintsMar 27 2018We prove density of smooth functions in subspaces of Sobolev- and higher order $BV$-spaces of kind $W^{m,p}(\Omega)\cap L^q(\Omega-D)$ and $BV^m(\Omega)\cap L^q(\Omega-D)$, respectively, where $\Omega\subset\mathbb{R}^n$ ($n\in\mathbb{N}$) is an open ... More
On some partial orders associated to generic initial idealsNov 16 1998Jun 02 2000We study two partial orders on $[x_1,...,x_n]$, the free abelian monoid on ${x_1,...,x_n}$. These partial orders, which we call the ``strongly stable'' and the ``stable'' partial order, are defined by the property that their filters are precisely the ... More
Arc-Disjoint Cycles and Feedback Arc SetsJun 24 2012Isaak posed the following problem. Suppose $T$ is a tournament having a minimum feedback arc set which induces an acyclic digraph with a hamiltonian path. Is it true that the maximum number of arc-disjoint cycles in $T$ equals the cardinality of minimum ... More
Measurable centres in convolution semigroupsJul 19 2011In a convolution semigroup over a locally compact group, measurability of the translation by a fixed element implies continuity. In other words, the measurable centre coincides with the topological centre.
Geometric proofs of theorems of Ax-Kochen and ErsovJan 14 2016We give an algebraic geometric proof of the Theorem of Ax and Kochen on p-adic diophantine equations in many variables. Unlike Ax-Kochen's proof, ours does not use any notions from mathematical logic and is based on weak toroidalization of morphisms. ... More