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Results for "Jan Ewald"

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Optimizing defence, counter-defence and counter-counter defence in parasitic and trophic interactions -- A modelling studyJul 10 2019In host-pathogen interactions, often the host (attacked organism) defends itself by some toxic compound and the parasite, in turn, responds by producing an enzyme that inactivates that compound. In some cases, the host can respond by producing an inhibitor ... More
Exact analytic characteristic initial data for axisymmetric, non-rotating, vacuum spacetimes, with an application to the binary black hole problemNov 21 1998Bondi's approach to the construction of a coordinate system is used with a different choice of gauge, in accordance with which the radial coordinate r is an affine parameter, to cast the metric tensor into a form suitable for use with the Newman-Penrose ... More
Parallelized Solution Method of the Three-dimensional Gravitational Potential on the Yin-Yang GridJun 12 2018Jul 12 2018We present a new method for solving the three-dimensional gravitational potential of a density field on the Yin-Yang grid. Our algorithm is based on a multipole decomposition and completely symmetric with respect to the two Yin-Yang grid patches. It is ... More
Topological defects and gravity in theories with extra dimensionsAug 15 2005Various solutions to higher-dimensional Einstein equations coupled to a series of physically different sources are considered and their properties of localization of gravity discussed. A numerical example of a solution to the Einstein equations coupled ... More
Imprints of Chameleon f(R) Gravity on Galaxy Rotation CurvesMay 30 2018Aug 14 2018Current constraints on gravity are relatively weak on galactic and intergalactic scales. Screened modified gravity models can exhibit complex behaviour there without violating stringent tests of gravity within our Solar System. They might hence provide ... More
Models of the Cosmological 21 cm Signal from the Epoch of Reionization Calibrated with Lyman-alpha and CMB DataJul 13 2016Sep 12 2016We present here 21 cm predictions from high dynamic range simulations for a range of reionization histories that have been tested against available Lyman-alpha and CMB data. We assess the observability of the predicted spatial 21 cm fluctuations by ongoing ... More
Optimal spectrum for the borocarbides YNi2B2C and LuNi2B2CJan 27 2001The concept of an optimal electron-phonon interaction spectral density as an Einstein spectrum which allows to describe all physical properties of a superconductor in an optimal way is developed from Carbotte's original definition of an optimum spectrum. ... More
The Bondi-Sachs metric at the vertex of a null cone: axially symmetric vacuum solutionsNov 21 2012Jan 11 2013In the Bondi-Sachs formulation of General Relativity space-time is foliated via a family of null cones. If these null cones are defined such that their vertices are traced by a regular world-line then the metric tensor has to obey regularity conditions ... More
Nearly Minimal MagnetogenesisMar 14 2004We propose a new mechanism for magnetic field generation from inflation, by which strong magnetic fields can be generated on cosmological scales. These fields may be observable by cosmic microwave background radition measurements, and may have a dynamical ... More
Cluster strong lensing in the Millennium Simulation: The effect of galaxies and structures along the line-of-sightApr 02 2009Jun 15 2009We use ray-tracing through the Millennium simulation to study how secondary matter structures along the line-of-sight and the stellar mass in galaxies affect strong cluster lensing, in particular the cross-section for giant arcs. Furthermore, we investigate ... More
Simulating Self-gravitating Hydrodynamic FlowsFeb 28 1994An efficient algorithm for solving Poisson's equation in two and three spatial dimensions is discussed. The algorithm, which is described in detail, is based on the integral form of Poisson's equation and utilizes spherical coordinates and an expansion ... More
Formation of spiral and elliptical galaxies in a CDM cosmogonySep 01 1993The formation of galaxies in a CDM cosmogony is investigated by following the evolution of dark and baryonic matter and of the frequency- dependent spatially averaged radiation field. The gas is allowed to form stars which are independently treated as ... More
Uniformly Valid Confidence Sets Based on the LassoJul 19 2015May 14 2018In a linear regression model of fixed dimension $p \leq n$, we construct confidence regions for the unknown parameter vector based on the Lasso estimator that uniformly and exactly hold the prescribed in finite samples as well as in an asymptotic setup. ... More
Three-dimensional reconstruction of the intra-cluster mediumDec 16 2005We propose and test a new method based on Richardson-Lucy deconvolution to reconstruct three-dimensional gas density and temperature distributions in galaxy clusters from combined X-ray and thermal Sunyaev-Zel'dovich observations. Clusters are assumed ... More
The formation of disk galaxies in a cosmological context: Populations, metallicities and metallicity gradientsDec 05 1993We present first results concerning the metallicities and stellar populations of galaxies formed in a cosmologically motivated simulation. The calculations include dark matter, gas dynamics, radiation processes, star formation, supernovae feedback, and ... More
On the Distribution, Model Selection Properties and Uniqueness of the Lasso Estimator in Low and High DimensionsAug 31 2017Jan 29 2018We derive expressions for the finite-sample distribution of the Lasso estimator in the context of a linear regression model with normally distributed errors in low as well as in high dimensions by exploiting the structure of the optimization problem defining ... More
Confidence Sets Based on the Lasso EstimatorJul 19 2015In a linear regression model with fixed dimension, we construct confidence sets for the unknown parameter vector based on the Lasso estimator in finite samples as well as in an asymptotic setup, thereby quantifying estimation uncertainty of this estimator. ... More
Parametric initial conditions for core-collapse supernova simulationsMar 17 2016May 11 2016We investigate a method to construct parametrized progenitor models for core-collapse supernova simulations. Different from all modern core-collapse supernova studies, which rely on progenitor models from stellar evolution calculations, we follow the ... More
Numerical simulations of the magnetorotational instability in protoneutron stars: I. Influence of buoyancyJan 30 2015Apr 24 2015The magneto-rotational instability (MRI) is considered to be a promising mechanism to amplify the magnetic field in fast rotating protoneutron stars. In contrast to accretion disks, radial buoyancy driven by entropy and lepton fraction gradients is expected ... More
The Formation of Disk Galaxies in a Cosmological Context: Structure and KinematicsJul 22 1994We present results concerning the internal structure and kinematics of disk galaxies formed in cosmologically motivated simulations. The calculations include dark matter, gas dynamics, radiative cooling, star formation, supernova feedback and metal enrichment. ... More
Localizing gravity on a 't Hooft-Polyakov monopole in seven dimensionsMay 31 2002We present regular solutions for a brane world scenario in the form of a 't Hooft-Polyakov monopole living in the three-dimensional spherical symmetric transverse space of a seven-dimensional spacetime. In contrast to the cases of a domain-wall in five ... More
Constraints on Chameleon-f(R) Gravity from Galaxy Rotation Curves of the SPARC SampleMay 30 2019In chameleon-$f(R)$ gravity, the fifth force will lead to `upturns' in galaxy rotation curves near the screening radius. The location of the upturn depends on the cosmic background value of the scalar field $f_{R0}$, as well as the mass, size and environment ... More
Photon mass generation during inflation: de Sitter invariant caseDec 10 2003May 24 2004We calculate the one-loop vacuum polarization tensor of scalar electrodynamics in a locally de Sitter space-time, endowed with a nearly minimally coupled, light scalar field. We show that the photon dynamics is well approximated by a (local) Proca Lagrangean. ... More
Spin Physics and Polarized Structure FunctionsOct 07 1998A review on the theoretical aspects and the experimental results of polarized deep inelastic scattering and of other hard scattering processes is presented. The following items are discussed: longitudinally polarized structure functions, results from ... More
Shaping the galaxy stellar mass function with supernova- and AGN-driven windsMay 11 2012Cosmological hydrodynamical simulations of galaxy formation in representative regions of the Universe typically need to resort to subresolution models to follow some of the feedback processes crucial for galaxy formation. Here, we show that an energy-driven ... More
Probing the dynamical state of galaxy clustersJun 05 2007We show how hydrostatic equilibrium in galaxy clusters can be quantitatively probed combining X-ray, SZ, and gravitational-lensing data. Our previously published method for recovering three-dimensional cluster gas distributions avoids the assumption of ... More
Rayleigh-Taylor finger instability mixing in hydrodynamic shell convection modelsMay 13 2010Mixing processes in stars driven by composition gradients as a result of the Rayleigh-Taylor instability are not anticipated. They are supported only by hydrodynamic studies of stellar convection. We find that such mixing occurs below the bottom edge ... More
AMRA: An Adaptive Mesh Refinement Hydrodynamic Code for AstrophysicsOct 31 2000Implementation details and test cases of a newly developed hydrodynamic code, AMRA, are presented. The numerical scheme exploits the adaptive mesh refinement technique coupled to modern high-resolution schemes which are suitable for relativistic and non-relativistic ... More
The Consistent Multi-fluid Advection methodJul 23 1998Nov 16 1998Simple modifications for higher-order Godunov-type difference schemes are presented which allow for accurate advection of multi-fluid flows in hydrodynamic simulations. The constraint that the sum of all mass fractions has to be equal to one in every ... More
Star-formation efficiency and metal enrichment of the intracluster medium in local massive clusters of galaxiesSep 02 2011Oct 14 2011We have investigated the baryon-mass content in a subsample of 19 clusters of galaxies extracted from the X-ray flux-limited sample HIFLUGCS according to their positions in the sky. For these clusters, we measured total masses and characteristic radii ... More
A Solar Prominence ModelSep 18 1997We propose a model for solar prominences based on converging flow observed in the chromosphere and photosphere. In contrast with existing models we do not apply a shearing motion along the neutral line. Instead we assume that bipolar loops approaching ... More
On invariant Schreier structuresSep 20 2013May 30 2014Schreier graphs, which possess both a graph structure and a Schreier structure (an edge-labeling by the generators of a group), are objects of fundamental importance in group theory and geometry. We study the Schreier structures with which unlabeled graphs ... More
Blowup of Jang's equation at outermost marginally trapped surfacesNov 29 2007Aug 17 2009The aim of this paper is to collect some facts about the blowup of Jang's equation. First, we discuss how to construct solutions that blow up at an outermost MOTS. Second, we exclude the possibility that there are extra blowup surfaces in data sets with ... More
NLO QCD corrections to W+b W-antib production at hadron colliders: new developments and new issuesDec 13 2014This short summary reviews the recent progress in the computation of higher-order corrections to W+b W-antib production. In addition, new phenomenological studies reveal potential problems that may affect precision measurements at the LHC.
Functional calculus for $C_{0}$-groups using (co)typeAug 09 2015We study the functional calculus properties of generators of $C_{0}$-groups under type and cotype assumptions on the underlying Banach space. In particular, we show the following. Let $-iA$ generate a $C_{0}$-group on a Banach space $X$ with type $p\in[1,2]$ ... More
Quantization of GeometryNov 22 1994Jun 08 1995Contents: 1. Introduction 2. Bosonic propagators and random paths 3. Random surfaces and strings 4. Matrix models and two-dimensional quantum gravity 5. The mystery of $c > 1$ 6. Euclidean quantum gravity in $d > 2$ 7. Discussion
Barriers in Quantum GravityAug 23 1994I discuss recent progress in our understanding of two barriers in quantum gravity: $c > 1$ in the case of 2d quantum gravity and $D > 2$ in the case of Euclidean Einstein-Hilbert gravity formulated in space-time dimensions $D >2$.
Indirect detection of Dark matter with gamma-rays - status and perspectivesMar 29 2011In my contribution I review the status of indirect detection of dark matter with gamma-rays, including results of the Fermi Gamma-ray Space Telescope as well as Imaging Air Cherenkov Telescopes (IACT), like H.E.S.S., MAGIC and VERITAS. I will also briefly ... More
Indirect Detection of WIMP Dark Matter: a compact reviewNov 07 2014Indirect detection of dark matter particles, i.e. the detection of annihilation or decay products of Weakly Interacting Massive Particles, has entered a pivotal phase as experiments reach sensitivities that probe the most interesting parameter space. ... More
On sensitivity calculations for neutrino oscillation experimentsOct 16 2007Calculations of sensitivities of future experiments are a necessary ingredient in experimental high energy physics. Especially in the context of measurements of the neutrino oscillation parameters extensive studies are performed to arrive at the optimal ... More
Beam Test Performance and Simulation of Prototypes for the ALICE Silicon Pixel DetectorNov 07 2005The silicon pixel detector (SPD) of the ALICE experiment in preparation at the Large Hadron Collider (LHC) at CERN is designed to provide the precise vertex reconstruction needed for measuring heavy flavor production in heavy ion collisions at very high ... More
eROSITA - Nearby Young Stars in X-raysOct 05 2015X-ray surveys are well suited to detect, identify and study young stars based on their high levels of magnetic activity and thus X-ray brightness. The eROSITA instrument onboard the Spectrum-Roentgen-Gamma (SRG) satellite will perform an X-ray all-sky ... More
Geometry of Membrane Sigma ModelsDec 27 2015String theory still remains one of the promising candidates for a unification of the theory of gravity and quantum field theory. One of its essential parts is relativistic description of moving multi-dimensional objects called membranes (or p-branes) ... More
A rigid Urysohn-like spaceNov 30 2015Recall that the Rado graph is the unique countable graph that realizes all one-point extensions of its finite subgraphs. The Rado graph is well-known to be universal and homogeneous in the sense that every isomorphism between finite subgraphs of $R$ extends ... More
An equivalence between Frobenius algebras and Calabi-Yau categoriesSep 21 2016We show that the bigroupoid of separable symmetric Frobenius algebras over an algebraically closed field and the bigroupoid of finitely semi-simple Calabi-Yau categories are equivalent. To this end, we construct a trace on the category of finitely-generated ... More
The Higgs Physics Program at the International Linear ColliderNov 01 2015The International Linear Collider (ILC) is a proposed electron -- positron collider with a collision energy of $\sqrt{s}$ = 500 GeV in the baseline configuration. The ILC physics program takes full advantage of the fact that the machine can be operated ... More
Charginos and Neutralinos at e+e- Linear CollidersMay 16 2002It is shown how the fundamental gaugino and higgsino parameters of the chargino and neutralino system in the MSSM can completely be determined in high--precision experiments at e+e- linear colliders even if in their initial phase only the light charginos ... More
Supersymmetry at and beyond the LHCApr 17 2008Prospects for SUSY discoveries and measurements at future colliders LHC and ILC are discussed. The problem of reconstructing the underlying theory and SUSY breaking mechanism is also addressed.
Testing CP Violation and Universal Extra Dimensions at Future CollidersOct 08 2004A future linear e+e- collider with a clean environment, tunable collision energy, high luminosity, polarized incoming beams, and additional e-e-, e-gamma and gamma-gamma modes, will offer precision tools to explore new physics. Here we summarize three ... More
Supersymmetric $W$ Boson Decays as a Means to Search for Charginos and NeutralinosMar 26 1997If the sneutrino mass is below the chargino mass, the dominant decay mode of the lightest chargino is via a two-body decay channel $\chi^{\pm}_1 \ra \tilde{\nu} + l^{\pm}$. Sneutrinos are invisible in $R$-parity conserving supersymmetric models and, if ... More
On the Existence of a Maximal Cauchy Development for the Einstein Equations - a DezornificationSep 29 2013Jul 02 2015In 1969, Choquet-Bruhat and Geroch established the existence of a unique maximal globally hyperbolic Cauchy development of given initial data for the Einstein equations. Their proof, however, has the unsatisfactory feature that it relies crucially on ... More
Approximate invariance of metabolic energy per synapse during development in mammalian brainsApr 17 2012During mammalian development the cerebral metabolic rate correlates qualitatively with synaptogenesis, and both often exhibit bimodal temporal profiles. Despite these non-monotonic dependencies, it is found based on empirical data for different mammals ... More
The extended states in disordered 1D systems in the presence of the generalized $N$-mer correlationsJul 07 2016Aug 22 2016We have been investigating the problem of the Anderson localization in a disordered one dimensional tight-binding model. The disorder is created by the interaction of mobile particles with other species, immobilized at random positions. We introduce a ... More
Wall-crossing of D4-branes using flow treesMar 08 2010The moduli dependence of D4-branes on a Calabi-Yau manifold is studied using attractor flow trees, in the large volume limit of the Kahler cone. One of the moduli dependent existence criteria of flow trees is the positivity of the flow parameters along ... More
Stability and duality in N=2 supergravityJun 09 2009Aug 17 2010The BPS-spectrum is known to change when moduli cross a wall of marginal stability. This paper tests the compatibility of wall-crossing with S-duality and electric-magnetic duality for N=2 supergravity. To this end, the BPS-spectrum of D4-D2-D0 branes ... More
Time-optimal Control of Spin SystemsJan 19 2006The paper discusses various aspects of time-optimal control of quantum spin systems, modelled as right-invariant systems on a compact Lie group G. The main results are the reduction of such a system to an equivalent system on a homogeneous space G/H, ... More
A modern, but way too short history of the theory of superconductivity at a high temperatureDec 25 2010Jan 04 2011An attempt to shed light on the various belief/idea systems in high Tc superconductivity that are at present popular. This text is in first instance intended to serve both string theorists and junior condensed matter physicists who want to enter this ... More
Boltzmann entropy and the microcanonical ensembleDec 24 2004Boltzmann's entropy is slightly modified to make it suitable for discussing phase transitions in finite systems. As an example it is shown that the pendulum undergoes a second order phase transition when passing from a vibrational to a rotating state. ... More
On the maximum entropy principle in non-extensive thermostatisticsMay 21 2004It is possible to derive the maximum entropy principle from thermodynamic stability requirements. Using as a starting point the equilibrium probability distribution, currently used in non-extensive thermostatistics, it turns out that the relevant entropy ... More
Parameter estimation in nonextensive thermostatisticsSep 30 2005Equilibrium statistical physics is considered from the point of view of statistical estimation theory. This involves the notions of statistical model, of estimators, and of exponential family. A useful property of the latter is the existence of identities, ... More
Continuity of a class of entropies and relative entropiesAug 26 2002Jan 30 2004The present paper studies continuity of generalized entropy functions and relative entropies defined using the notion of a deformed logarithmic function. In particular, two distinct definitions of relative entropy are discussed. As an application, all ... More
Nuclear shadowing in the light-cone dipole approachMar 12 2008We study nuclear shadowing at small Bjorken x < 0.01 in the color dipole approach. Such a light-cone quantum-chromodynamics formalism based on the Green function technique incorporates naturally color transparency and coherence length effects. The nuclear ... More
Topological Quantum Field Theory and Pure Yang-Mills DynamicsAug 03 2004Aug 03 2006By considering specific limits in the gauge coupling constant of pure Yang--Mills dynamics, it is shown how there exist topological quantum field theory sectors in such systems defining nonperturbative topological configurations of the gauge fields which ... More
Positronium Spectroscopy in a Magnetic FieldAug 09 1993Hyperfine spectroscopy of positronium formed in the presence of a static magnetic field is considered. Generalising the situation hitherto developed in the literature, the magnetic field is not assumed to be parallel to the momentum of incoming polarised ... More
Finite Euler Hierarchies And Integrable Universal EquationsJul 13 1992Jul 23 1992Recent work on Euler hierarchies of field theory Lagrangians iteratively constructed {}from their successive equations of motion is briefly reviewed. On the one hand, a certain triality structure is described, relating arbitrary field theories, {\it classical\ts} ... More
The AdS3 boundary energy momentum tensor, exact in the string length over the curvature radiusJun 22 2010We first clarify the relation between boundary perturbations of AdS3 in general relativity, and exactly marginal worldsheet vertex operators in AdS3 string theory with Neveu-Schwarz Neveu-Schwarz flux. The latter correspond to solutions of the higher ... More
The non-compact elliptic genus: mock or modularApr 21 2010Jun 17 2010We analyze various perspectives on the elliptic genus of non-compact supersymmetric coset conformal field theories with central charge larger than three. We calculate the holomorphic part of the elliptic genus via a free field description of the model, ... More
Pseudo-finite hard instances for a student-teacher game with a Nisan-Wigderson generatorJul 02 2012Aug 10 2012For an NP intersect coNP function g of the Nisan-Wigderson type and a string b outside its range we consider a two player game on a common input a to the function. One player, a computationally limited Student, tries to find a bit of g(a) that differs ... More
Excitonic condensation in systems of strongly correlated electronsMay 06 2015The idea of exciton condensation in solids was introduced in 1960's with the analogy to superconductivity in mind. While exciton supercurrents have been realized only in artificial quantum-well structures so far, the application of the concept of excitonic ... More
A simple model of the reflection effect for the interacting binaries and extrasolar planetsMar 08 2010May 22 2010Extrasolar planets are a natural extension of the interacting binaries towards the companions with very small masses and similar tools might be used to study them. Unfortunately, the generally accepted treatment of the reflection effect in interacting ... More
Non-accessible critical points of Cremer polynomialsFeb 12 1995It is shown that a polynomial with a Cremer periodic point has a non-accessible critical point in its Julia set provided that the Cremer periodic point is approximated by small cycles.
Did one observe couplings of right-handed quarks to W ?Sep 21 2007I consider non standard EW couplings of light right-handed quarks to W and Z suggested in a systematic non decoupling bottom-up low-energy effective theory approach to possible extensions of the Standard Model. New experimental tests in K^L_{mu3} decays ... More
Two alternatives of spontaneous chiral symmetry breaking in QCDJan 13 1998Considering QCD in an Euclidean box, the mechanism of spontaneous breaking of chiral symmetry (SB$\chi$S) is analyzed in terms of average properties of lowest eigenstates of the Dirac operator. A formal analogy between the pion decay constant and conductivity ... More
Light quarks masses and condensates in QCDDec 18 1997We review some theoretical and phenomenological aspects of the scenario in which the spontaneous breaking of chiral symmetry is not triggered by a formation of a large condensate <\bar{q} q>. Emphasis is put on the resulting pattern of light quark masses, ... More
A note on concentration of submodular functionsMay 17 2010We survey a few concentration inequalities for submodular and fractionally subadditive functions of independent random variables, implied by the entropy method for self-bounding functions. The power of these concentration bounds is that they are dimension-free, ... More
On statistical arc length of the Riemann $Z(t)$-curveJun 08 2015In this paper we study certain stochastic process that is generated by the Riemann-Siegel formula. Further, we construct corresponding statistical model by a way similar to those used in telecommunication. We define statistical arc length of the Riemann ... More
Properties of the sequence $\{Z[t_ν(τ)]\}$, Jacob's ladders and new kind of infinite set of metamorphosis of main multiformFeb 18 2015In this paper we study properties of some sums of members of the sequence $\{Z[t_\nu(\tau)]\}$. Our results are expressed in statements proving essential influence of the Lindel\" of hypothesis on corresponding formulae. In this paper: the parts 1 -- ... More
$Ω$-theorem for short trigonometric sumJun 26 2014We obtain in this paper new application of the classical E.C. Titchmarsh' discrete method (1934) in the theory of the Riemann $\zf$ - function. Namely, we shall prove the first localized $\Omega$-theorem for short trigonometric sum. This paper is the ... More
Jacob's ladders, Gram's sequence and some nonlinear integral equations connected with the functions $J_ν(x)$ and $|\zf|^4$Nov 29 2010It is shown in this paper that the Jacob's ladder is the asymptotic solution to the new nonlinear integral equations which correspond to the functions $J_\nu(x)$ and $|\zf|^4$.
Jacob's ladders, Bessel's functions and the asymptotic solutions of a new class of nonlinear integral equationsNov 15 2010It is shown in this paper that there is a connection between the Riemann zeta-function $\zf$ and the Bessel's functions. In this direction, a new class of the nonlinear integral equations is introduced.
Jacob's ladders and the nonlocal interaction of the function $Z^2(t)$ with the function $\tilde{Z}^2(t)$ on the distance $\sim (1-c)π(t)$ for the collections of disconnected setsJul 29 2010It is shown in this paper that there is a fine correlation of the fourth order between the functions $Z^2[\vp_1(t)]$ and $\tilde{Z}^2(t)$, respectively. This correlation is with respect to two collections of disconnected sets. Corresponding new asymptotic ... More
Improvement of the theorem of Hardy-Littlewood on density of zeros of the function $ζ(1/2+it)$Sep 10 2014In this paper we improve classical Hardy-Littlewood exponent $1/2$ by about $16.6\%$ 62 years after the original result. This result is the first step to prove the Selberg's hypothesis (1942). In order to reach our purpose we use discrete method. This ... More
Jacob's ladders and the quantization of the Hardy-Littlewood integralSep 22 2009We use Jacob's ladders to solve the fine problem how to divide of the Hardy-Littlewood integral to equal parts, for example of magnitude $h=6.6\times 10^{-27}$ (the numerical value of elementary Planck quantum). The result of the paper cannot be obtained ... More
Characterisation of the Energy of Gaussian Beams on Lorentzian Manifolds - with Applications to Black Hole SpacetimesNov 11 2013Jan 10 2016It is known that using the Gaussian beam approximation one can show that there exist solutions of the wave equation on a general globally hyperbolic Lorentzian manifold whose energy is localised along a given null geodesic for a finite, but arbitrarily ... More
Hypergeometric type functions and their symmetriesMay 14 2013Aug 04 2013We give a systematic and unified discussion of various classes of hypergeometric type equations: the hypergeometric equation, the confluent equation, the F_1 equation (equivalent to the Bessel equation), the Gegenbauer equation and the Hermite equation. ... More
On the classification of rational surface singularitiesApr 01 2012A general strategy is given for the classification of graphs of rational surface singularities. For each maximal rational double point configuration we investigate the possible multiplicities in the fundamental cycle. We classify completely certain types ... More
Grassmannians and Koszul dualityNov 08 2013Jun 13 2014Let $X$ be a partial flag variety, stratified by orbits of the Borel. We give a criterion for the category of modular perverse sheaves to be equivalent to modules over a Koszul ring. This implies that modular category $\mathcal O$ is governed by a Koszul-algebra ... More
Fostering Consensus in Multidimensional Continuous Opinion Dynamics under Bounded ConfidenceAug 23 2007Social consensus is important for society. Sometimes the success of society depends on a consensus (e.g. the decision to pay taxes or to commit to the constitution). Examples for continuous opinion dynamics are discussions about tax rates or budget plan ... More
Continuous Opinion Dynamics under Bounded Confidence: A SurveyJul 12 2007Jan 18 2008Models of continuous opinion dynamics under bounded confidence have been presented independently by Krause and Hegselmann and by Deffuant et al in 2000. They have raised a fair amount of attention in the communities of social simulation, sociophysics ... More
Moduli spaces of Higgs bundles on degenerating Riemann surfacesJul 15 2015We prove a gluing theorem for solutions of Hitchin's self-duality equations with logarithmic singularities on a rank-2 vector bundle over a noded Riemann surface representing a boundary point of Teichm\"uller moduli space.
Real time simulations and the electroweak phase transitionOct 06 1997We review recent developments in real-time simulations of SU(2)-Higgs theory near the electroweak transition and related topics.
On Selberg's theorem C in the theory of the Riemann zeta-functionSep 16 2014In this paper we obtain new theorems about classes of exceptional sets for the Selberg's theorem C (1942). Our theorems, as based on discrete method, are not accessible for Karatsuba's theory (1984) since this theory is a continuous theory. This paper ... More
Can We Observe the Quark Gluon Plasma in Cosmic Ray Showers ?Dec 06 2000Aug 08 2001The possibility of detection of some features of high energy particle interactions with detectors placed at medium depths underground through studies on high energy muons is investigated. These muons carry information about the early interactions occurring ... More
Gravitino DM and high reheating temperatures after LHC 7/8May 20 2014The presence of high reheating temperatures in the thermal history of the universe challenges supersymmetric scenarios owing to the gravitino problem. We revise a general R-parity conserving gravitino dark matter scenario with a stau as the next-to-lightest ... More
Elegent -- an elastic event generatorOct 08 2013Although elastic scattering of nucleons may look like a simple process, it presents a long-lasting challenge for theory. Due to missing hard energy scale, the perturbative QCD can not be applied. Instead, many phenomenological/theoretical models have ... More
Plactic monoids satisfy nontrivial identitiesFeb 17 2019Mar 27 2019It is shown that the plactic monoid P_n of any fixed rank n satisfies a nontrivial identity.
A saturation property of structures obtained by forcing with a compact family of random variablesJul 06 2012Aug 10 2012A method how to construct Boolean-valued models of some fragments of arithmetic was developed in Krajicek (2011), with the intended applications in bounded arithmetic and proof complexity. Such a model is formed by a family of random variables defined ... More
Out-of-time-ordered correlation functions in open systems: A Feynman-Vernon influence functional approachMar 12 2019We study out-of-time-ordered correlation functions (OTOCs) in open quantum systems. As most experimental protocols for measuring OTOCs are based on backward time evolution we consider two possible scenarios of joint system-environment dynamics reversal: ... More
Plactic monoids satisfy nontrivial identitiesFeb 17 2019It is shown that the plactic monoid P_n of any fixed rank n satisfies a nontrivial identity.
A light singlet at the LHC and DMMay 22 2018An interesting scenario of an R-symmetric supersymmetric model with a light singlet is discussed. Since a light scalar in this model necessarily implies a light Dirac neutralino, its viability as a dark matter candidate is addressed.