Results for "Günter Sigl"

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Anisotropies of Ultra-high Energy Cosmic Rays Dominated by a Single Source in the Presence of DeflectionsOct 16 2017Jan 08 2019This work presents a scenario of ultra-high energy cosmic ray source distribution where a nearby source is solely responsible for the anisotropies in arrival directions of cosmic rays while the rest of the sources contribute only isotropically. An analytical ... More
Constraining ALP-photon coupling using galaxy clustersJul 10 2015Feb 04 2016We study photon-ALP conversion by resonance effects in the magnetized plasma of galaxy clusters and compare the predicted distortion of the cosmic microwave background spectrum in the direction of such objects to measurements of the thermal Sunyaev-Zeldovich ... More
On minimal energy states of chiral MHD turbulenceJun 17 2018Jan 10 2019We study the evolution of magnetohydrodynamic turbulence taking into account the chiral anomaly effect. This chiral magnetohydrodynamic description of the plasma is expected to be relevant for temperatures comparable to the electroweak scale, and therefore ... More
Chiral Magnetic Effect in Protoneutron Stars and Magnetic Field Spectral EvolutionJul 17 2015Dec 15 2015We investigate the evolution of the chiral magnetic instability in a protoneutron star and compute the resulting magnetic power and helicity spectra. The instability may act during the early cooling phase of the hot protoneutron star after supernova core ... More
Axion-like Dark Matter Constraints from CMB BirefringenceNov 19 2018Axion-like particles are dark matter candidates motivated by the Peccei-Quinn mechanism and also occur in effective field theories where their masses and photon couplings are independent. We estimate the dispersion of circularly polarized photons in a ... More
Axion Condensate Dark Matter Constraints from Resonant Enhancement of Background RadiationJul 10 2019We investigate the possible parametric growth of photon amplitudes in a background of axion-like particle (ALP) dark matter. The observed extragalactic background radiation limits the allowed enhancement effect. We derive the resulting constraints on ... More
Chiral Magnetohydrodynamic TurbulenceDec 21 2016Sep 10 2017In this work the influence of the chiral anomaly effect on the evolution of magnetohydrodynamic turbulence was studied. We argue that in the early universe, before the electroweak symmetry breaking, and for temperatures high enough such that the electron ... More
Modified Magnetohydrodynamics Around the Electroweak TransitionFeb 26 2016Jul 13 2016We analyse solutions of the MHD equations around the electroweak transition taking into account the effects of the chiral anomaly. It is shown that a transition that is not of the first order has direct consequences on the evolution of the asymmetry between ... More
Testing Lorentz invariance with neutrino bursts from supernova neutronizationNov 29 2012Feb 21 2013Quantum-gravity (QG) effects might generate Lorentz invariance violation by the interaction of energetic particles with the foamy structure of the space-time. As a consequence, particles may not travel at the universal speed of light. We propose to constrain ... More
Indirect and direct search for dark matterJul 14 2015The majority of the matter in the universe is still unidentified and under investigation by both direct and indirect means. Many experiments searching for the recoil of dark-matter particles off target nuclei in underground laboratories have established ... More
Liouville term for neutrinos: Flavor structure and wave interpretationMar 13 2018Neutrino production, absorption, transport, and flavor evolution in astrophysical environments is described by a kinetic equation $D\varrho=-i[{\sf H},\varrho]+{\cal C}[\varrho]$. Its basic elements are generalized occupation numbers $\varrho$, matrices ... More
High Energy Astroparticle PhysicsDec 09 2006We give a brief (and highly incomplete) overview of the current experimental and theoretical status of high energy cosmic rays and their secondary gamma-rays and neutrinos. We focus on the role of large scale magnetic fields and on multi-messenger aspects ... More
Some Current Theoretical Issues around Ultra-High Energy Cosmic RaysApr 03 2004We address some current theoretical issues around ultra-high energy cosmic rays. We recall that scenarios producing more gamma-rays than cosmic rays up to high redshift can in general only provide a sub-dominant contribution to the ultra-high energy cosmic ... More
Topological Defect Models of Ultra-High Energy Cosmic RaysNov 22 1996We give an overview over models in which cosmic rays above 1 EeV = 10**(18) eV are produced by the decay of supermassive "X" particles released from topological defects possibly created in cosmological phase transitions. We note that, for an interesting ... More
Interdisciplinary Aspects of High-Energy AstrophysicsFeb 07 2011Modern astrophysics, especially at GeV energy scales and above is a typical example where several disciplines meet: The location and distribution of the sources is the domain of astronomy. At distances corresponding to significant redshift cosmological ... More
Time Structure of Ultra-High Energy Cosmic Ray Sources and Consequences for Multi-messenger SignaturesMar 26 2008The latest results on the sky distribution of ultra-high energy cosmic ray sources have consequences for their nature and time structure. If the sources accelerate predominantly nuclei of atomic number A and charge Z and emit continuously, their luminosity ... More
Particle and Astrophysics Aspects of Ultrahigh Energy Cosmic RaysAug 23 2000Dec 09 2000The origin of cosmic rays is one of the major unresolved astrophysical questions. In particular, the highest energy cosmic rays observed possess macroscopic energies and their origin is likely to be associated with the most energetic processes in the ... More
Cosmic rays and neutrino interactions beyond the standard modelJan 06 2000Some solutions of the hierarchy problem of particle physics can lead to significantly increased neutrino cross sections beyond the electroweak scale. We discuss some consequences for and constraints resulting from cosmic ray physics.
Non-Universal Spectra of Ultra-High Energy Cosmic Ray Primaries and Secondaries in a Structured UniverseMar 15 2007May 26 2007Analytical calculations of extra-galactic cosmic ray spectra above ~10^17 eV are often performed assuming continuous source distributions, giving rise to spectra that depend little on the propagation mode, be it rectilinear or diffusive. We perform trajectory ... More
Nucleon Spin Fluctuations and Neutrino-Nucleon Energy Transfer in SupernovaeMar 10 1997The formation of neutrino spectra in a supernova depends crucially on strength and inelasticity of weak interactions in hot nuclear matter. Neutrino interactions with nonrelativistic nucleons are mainly governed by the dynamical structure function for ... More
TOPOLOGICAL DEFECTS AND HIGHEST ENERGY COSMIC AND GAMMA RAYSMar 02 1995In this paper we review the hypothesis that a considerable part of the cosmic ray flux observed above about $10^{19}\eV$ may be produced by decaying or annihilating topological defects left over from phase transitions in the early universe at grand unification ... More
Lectures on Astroparticle PhysicsAug 16 2004These are extended notes of a series of lectures given at the XIth Brazilian School of Cosmology and Gravitation. They provide a selection of topics at the intersection of particle and astrophysics. The first part gives a short introduction to the theory ... More
Ultra-High Energy Cosmic Rays: A Probe of Physics and Astrophysics at Extreme EnergiesApr 17 2001The origin of cosmic rays is one of the major unresolved questions in astrophysics. In particular, the highest energy cosmic rays observed possess macroscopic energies and their origin is likely associated with the most energetic processes in the Universe. ... More
Collisional triggering of fast flavor conversions of supernova neutrinosAug 20 2018Mar 08 2019Fast flavor conversions of supernova neutrinos, possible near the neutrinosphere, depends on an interesting interplay of collisions and neutrino oscillations. Contrary to naive expectations, the rate of self-induced neutrino oscillations, due to neutrino-neutrino ... More
Extragalactic Sources and Propagation of UHECRsMay 05 2017With the publicly available astrophysical simulation framework for propagating extraterrestrial UHE particles, CRPropa 3, it is now possible to study realistic UHECR source scenarios including deflections in Galactic and extragalactic magnetic fields ... More
Neutrinos with Magnetic Moment: Depolarization Rate in PlasmaMar 03 1997Jul 25 1997Neutrinos with a magnetic moment $\mu$ change their helicity when interacting with an electromagnetic field. Various aspects of this effect have been described as spin precession, spin-flip scattering, and magnetic Cherenkov radiation. These perspectives ... More
Open Questions in Cosmic-Ray Research at Ultrahigh EnergiesMar 15 2019We review open questions and prospects for progress in ultrahigh-energy cosmic ray (UHECR) research, based on a series of discussions that took place during the `The High-Energy Universe: Gamma-Ray, Neutrino, and Cosmic-ray Astronomy' MIAPP workshop in ... More
Nonstandard general relativity III: The Kerr classJan 10 2013We revisit the Kerr metric in Boyer-Lindquist coordinates and construct the corresponding class of nonstandard solutions of Einstein's equations. These solutions can be used to describe the outer part of spiral galaxies without assuming dark matter.
Perturbation theory in nonstandard cosmologyApr 30 2019We study inhomogeneous perturbations away from the strongly homogeneous background cosmology previously studied. The problem is greatly simplified by using the mapping on the inner Schwarzschild solution. The resulting linear perturbation equations can ... More
The Largest Quadrilateral in a Convex PolygonMay 27 2019We present a simple linear-time algorithm for finding the quadrilateral of largest area contained in a convex polygon.
Stochastic analysis for Poisson processesMay 17 2014This survey is a preliminary version of a chapter of the forthcoming book "Stochastic Analysis for Poisson Point Processes: Malliavin Calculus, Wiener-It\^o Chaos Expansions and Stochastic Geometry" edited by Giovanni Peccati and Matthias Reitzner. The ... More
Nonstandard cosmologySep 21 2013Jan 09 2014Considering radial geodesics in the Robertson-Walker metric leads us to abandon the co-moving coordinates. Instead we work in the cosmic rest frame. Since then the matter is in motion, the solution of Einstein's equations is more complicated. We calculate ... More
An Introduction to the Mathematics of Anderson LocalizationApr 12 2011We give a widely self-contained introduction to the mathematical theory of the Anderson model. After defining the Anderson model and determining its almost sure spectrum, we prove localization properties of the model. Here we discuss spectral as well ... More
Objections to the Unified Approach to the Computation of Classical Confidence LimitsSep 24 1998Conventional classical confidence intervals in specific cases are unphysical. A solution to this problem has recently been published by Feldman and Cousins. We show that there are cases where the new approach is not applicable and that it does not remove ... More
Redshift-distance relation in inhomogeneous cosmologyMar 17 2015We continue to study a cosmological model with large-scale inhomogeneity. Working in the cosmic rest frame we determine null geodesics, redshift and area and luminosity distance. Combining the result with Hubble's law enables us to calculate the distance ... More
Against geometry: Nonstandard general relativityAug 18 2012Apr 26 2015We show that the Schwarzschild solution can be embedded in a class of nonstandard solutions of the vacuum Einstein's equations with arbitrary rotation curves. These nonstandard solutions have to be taken as physical if dark matter as needed in the standard ... More
Enhancing Battle Maps through Flow GraphsJun 11 2019So-called battle maps are an appropriate way to visually summarize the flow of battles as they happen in many team-based combat games. Such maps can be a valuable tool for retrospective analysis of battles for the purpose of training or for providing ... More
Characterization of the response maps of alternating-current networksApr 03 2019In an alternating-current network, each edge has a complex "conductance" with positive real part. The response map is the linear map from the vector of voltages at a subset of "boundary nodes" to the vector of currents flowing into the network through ... More
Neutrino Flavor Conversion in a Supernova CoreSep 24 1992If $\nu_\mu$ or $\nu_\tau$ mix with $\nu_e$, neutrino oscillations and collisions in a supernova (SN) core allow these flavors effectively to participate in $\beta$ equilibrium and thus to obtain a large chemical potential. If a sterile species mixes ... More
Is dark matter a phantom ?Jun 09 2012Jul 20 2012We show that Einstein's equations in a non-standard gauge have vacuum solutions with an asymptotically flat rotation curve as it is observed in the dark halos of galaxies. Introducing a material disk into this model we find a matter density in accordance ... More
Dark matter in galaxies according to the tensor-four-scalars theory IIIMay 19 2012We continue the study of the tensor-four-scalars theory which is a modification of general relativity. We include normal matter by applying the displace, cut, and reflect method to our previous vacuum solutions with dark halo. The resulting disklike solution ... More
Superluminal Tunneling DevicesApr 16 2002Photonic tunneling permits superluminal signal transmission. The principle of causality is not violated but the time duration between cause and effect can be shortened compared with an interaction exchange with velocity of light. This outstanding property ... More
Cosmology with the cosmic rest frameMar 17 2015May 28 2018We assume a one-to-one correspondence between comoving coordinates and the cosmic rest frame in a spherically symmetric inhomogeneous universe. This strongly restricts the solutions of Einstein's equations: (i) The pressure must be zero. (ii) The metric ... More
Ultra-High Energy Neutrino Fluxes: New Constraints and ImplicationsSep 29 2003We apply new upper limits on neutrino fluxes and the diffuse extragalactic component of the GeV gamma-ray flux to various scenarios for ultra high energy cosmic rays and neutrinos. As a result we find that extra-galactic top-down sources can not contribute ... More
Monopole Annihilation and Highest Energy Cosmic RaysDec 15 1994Cosmic rays with energies exceeding $10^{20}\eV$ have been detected. The origin of these highest energy cosmic rays remains unknown. Established astrophysical acceleration mechanisms encounter severe difficulties in accelerating particles to these energies. ... More
Local Magnetic Turbulence and TeV-PeV Cosmic Ray AnisotropiesNov 10 2011Aug 22 2012In the energy range from ~ 10^12 eV to ~ 10^15 eV, the Galactic cosmic ray flux has anisotropies both on large scales, with an amplitude of the order of 0.1%, and on scales between ~ 10 and ~ 30 degrees, with amplitudes smaller by a factor of a few. With ... More
General massive gauge theoryJan 27 1999The concept of perturbative gauge invariance formulated exclusively by means of asymptotic fields is used to construct massive gauge theories. We consider the interactions of $r$ massive and $s$ massless gauge fields together with $(r+s)$ fermionic ghost ... More
Inhomogeneous cosmology in the cosmic rest frame without dark stuffDec 10 2013Feb 22 2016We study Einstein's equations with an isotropic but inhomogeneous metric in the cosmic rest frame. The equations are solved perturbatively in the late Universe. The leading plus next-to-leading order results agree with observations without using a cosmological ... More
Harish-Chandra Modules over $\Bbb Z$Jul 02 2014In this note we discuss the concept of Harish-Chandra modules over the integers. The main result is a rationality result for certain intertwining operator which is used in a joint paper with Raghuram. We also discuss an interesting question concerning ... More
Nonstandard general relativity IIOct 04 2012Dec 01 2012We study Einstein's equations with matter in hydrostatic equilibrium in the nonstandard gauge which was recently investigated in the vacuum case. We obtain spherically symmetric solutions for any given rotation curve. These solutions can be used to describe ... More
Perturbation analysis of Poisson processesMar 14 2012Mar 07 2014We consider a Poisson process $\Phi$ on a general phase space. The expectation of a function of $\Phi$ can be considered as a functional of the intensity measure $\lambda$ of $\Phi$. Extending earlier results of Molchanov and Zuyev [Math. Oper. Res. 25 ... More
Comment on "Retrieval of phase relation and emission profile of quantum cascade laser frequency combs''May 13 2019A recent publication on arXiv:1905.00668 suggests that the phase relationship within a frequency comb can be reconstructed from a heterodyne measurement using a reference comb. In principle, following this approach, such retrieval of optical phases appears ... More
The Largest Contained Quadrilateral and the Smallest Enclosing Parallelogram of a Convex PolygonMay 27 2019Jun 18 2019We present a linear-time algorithm for finding the quadrilateral of largest area contained in a convex polygon, and we show that it is closely related to an old algorithm for the smallest enclosing parallelogram of a convex polygon.
Minimal Dominating Sets in a Tree: Counting, Enumeration, and Extremal ResultsMar 11 2019A tree with $n$ vertices has at most $95^{n/13}$ minimal dominating sets. The growth constant $\lambda = \sqrt[13]{95} \approx 1.4194908$ is best possible. It is obtained in a semi-automatic way as a kind of "dominant eigenvalue" of a bilinear operation ... More
On the Existence Theory of Hilbert Space valued Diffusion ProcessesAug 16 2010We prove that the solution of certain linear stochastic differential equations in Hilbert spaces, namely those with bounded operators as well as the conservative stochastic Schr\"odinger equations, can be obtained - along the lines of the Lie-Trotter ... More
An integral characterization of the Dirichlet processMar 30 2018We give a new integral characterization of the Dirichlet process on a general phase space. To do so we first prove a characterization of the nonsymmetric Beta distribution via size-biased sampling. Two applications are a new characterization of the Dirichlet ... More
Gravitational Effects on Particle Dark Matter and Indirect DetectionJul 10 2003The annihilation signal of particle dark matter can be strongly enhanced in over-dense regions such as close to the Galactic centre. We summarize some of our recent results on fluxes of gamma-rays, neutrinos and radio waves under different assumptions ... More
Reconstruction of Source and Cosmic Magnetic Field Characteristics from Clusters of Ultra-High Energy Cosmic RaysNov 06 1997We present a detailed Monte Carlo study coupled to a likelihood analysis of the potential of next generation ultra-high energy cosmic ray experiments to reconstruct properties of the sources and the extra-galactic magnetic field. Such characteristics ... More
Dark Matter Signatures in the Anisotropic Radio SkyJul 22 2008Oct 02 2008We calculate intensity and angular power spectrum of the cosmological background of synchrotron emission from cold dark matter annihilations into electron positron pairs. We compare this background with intensity and anisotropy of astrophysical and cosmological ... More
Lorentz Violation and Ultrahigh-Energy PhotonsJul 08 2008Sep 05 2008The propagation of photons, electrons and positrons at ultra-high energies above 10^{19} eV can be changed considerably if the dispersion relations of these particles are modified by terms suppressed by powers of the Planck scale. We recently pointed ... More
Do Cosmic Rays Heat the Early Intergalactic Medium?Mar 27 2017Cosmic rays (CRs) govern the energetics of present-day galaxies and might have also played a pivotal role during the Epoch of Reionization. In particular, energy deposition by low-energy ($E \lesssim 10$ MeV) CRs accelerated by the first supernovae, might ... More
Massive Tau Neutrino and SN 1987aMay 15 1994The emission of $\MeV$-mass tau neutrinos from newly formed neutron stars is considered in a simple, but accurate, model based upon the diffusion approximation. The tau-neutrinosphere temperature is found to increase with mass so that emission of massive ... More
CRPropa 3.1 -- A low energy extension based on stochastic differential equationsApr 24 2017Jun 06 2017The propagation of charged cosmic rays through the Galactic environment influences all aspects of the observation at Earth. Energy spectrum, composition and arrival directions are changed due to deflections in magnetic fields and interactions with the ... More
Mean-field predictions for a dipolar Bose-Einstein condensate with $^{164}$DyOct 22 2015Nov 06 2015We study dipolar Bose-Einstein condensates for a realistic set of parameters close to actual experimental setups with dysprosium. Our analysis is based on the extended Gross-Pitaevskii equation, which we solve numerically exact on a three-dimensional ... More
WDX-Analysis of the New Superconductors RO(1-x)F(x)FeAs and Its Consequences on the Electronic Phase DiagramJun 01 2009Polycrystalline samples of RO1-xFxFeAs (0 < x < 0.25) (R = La, Sm, Gd) were investigated by wavelength-dispersive X-ray spectroscopy (WDX) in the electron microscope to determine the composition of the samples, in particular the fluorine content. It was ... More
LightRel SemEval-2018 Task 7: Lightweight and Fast Relation ClassificationApr 19 2018We present LightRel, a lightweight and fast relation classifier. Our goal is to develop a high baseline for different relation extraction tasks. By defining only very few data-internal, word-level features and external knowledge sources in the form of ... More
Eisenstein Cohomology for GL(N) and ratios of critical values of Rankin-Selberg L-functionsMay 26 2014Jun 28 2015The aim of this article is to study rank-one Eisenstein cohomology for the group GL(N)/F, where F is a totally real field extension of Q. This is then used to prove rationality results for ratios of successive critical values for Rankin-Selberg L-functions ... More
Percolation on stationary tessellations: models, mean values and second order structureDec 22 2013We consider a stationary face-to-face tessellation $X$ of $\mathbb{R}^d$ and introduce several percolation models by colouring some of the faces black in a consistent way. Our main model is cell percolation, where cells are declared black with probability ... More
Additive structures on $f$-vector sets of polytopesSep 06 2017Sep 13 2017We show that the $f$-vector sets of $d$-polytopes have non-trivial additive structure: They span affine lattices and are embedded in monoids that we describe explicitly. Moreover, for many large subclasses, such as the simple polytopes, or the simplicial ... More
Face numbers of 4-Polytopes and 3-SpheresAug 09 2002Jun 20 2003In this paper, we discuss f- and flag-vectors of 4-dimensional convex polytopes and cellular 3-spheres. We put forward two crucial parameters of fatness and complexity: Fatness F(P) := (f_1+f_2-20)/(f_0+f_3-10) is large if there are many more edges and ... More
Polynomial parametrization of the solutions of Diophantine equations of genus 0Dec 01 2008Let f in Z[X,Y,Z] be a non-constant, absolutely irreducible, homogeneous polynomial with integer coefficients, such that the projective curve given by f=0 has a function field isomorphic to the rational function field Q(t). We show that all integral solutions ... More
On maximal hard-core thinnings of stationary particle processesJul 03 2017The present paper studies existence and distributional uniqueness of subclasses of stationary hard-core particle systems arising as thinnings of stationary particle processes. These subclasses are defined by natural maximality criteria. We investigate ... More
Magnetic horizons of ultra-high energy cosmic raysOct 28 2014The propagation of ultra-high energy cosmic rays in extragalactic magnetic fields can be diffusive, depending on the strength and properties of the fields. In some cases the propagation time of the particles can be comparable to the age of the universe, ... More
Diffusion of cosmic rays at EeV energies in inhomogeneous extragalactic magnetic fieldsJul 23 2014Nov 21 2014Ultra-high energy cosmic rays can propagate diffusively in cosmic magnetic fields. When their propagation time is comparable to the age of the universe, a suppression in the flux relative to the case in the absence of magnetic fields will occur. In this ... More
Diagonal Metrics of Static, Spherically Symmetric Fields The Geodesic Equations and the Mass-Energy Relation from the Coordinate PerspectiveJul 14 2014The geodesic equations for the general case of diagonal metrics of static, spherically symmetric fields are calculated. The elimination of the proper time variable gives the motion equations for test particles with respect to coordinate time and an account ... More
The Superluminal Tunneling StoryApr 10 2013Since 1992 experimental evidence of superluminal (faster than light, FTL) signals are causing much excitement in the physical community and in the media. Superluminal signal velocity and zero time tunneling was first observed in an analog tunneling experiment ... More
Phonon instability and self-organized structures in multi-layer stacks of confined dipolar Bose-Einstein condensates in optical latticesAug 07 2009In calculations to date [1,2] of multi-layer stacks of dipolar condensates, created in one-dimensional optical lattices, the condensates have been assumed to be two-dimensional. In a real experiment, however, the condensates do not extend to infinity ... More
Model Studies on the Quantum Jarzynski RelationAug 10 2007Dec 04 2007We study the quantum Jarzynski relation for driven quantum models embedded in various environments. We do so by generalizing a proof presented by Mukamel [Phys. Rev. Lett 90, 170604 (2003)] for closed quantum systems. In this way, we are able to prove ... More
Effective environments: Preparation of stationary states with inverse temperature ranging from positive to negative valuesJul 18 2011In this paper, we discuss how effective environments incorporating periodic measurements can be used to prepare a two-level system (TLS) in almost arbitrary thermal states: Concretely, we study a TLS coupled to a spin environment, the magnetization of ... More
Work exchange between quantum systems: the spin-oscillator modelNov 27 2009With the development of quantum thermodynamics it has been shown that relaxation to thermal equilibrium and with it the concept of heat flux may emerge directly from quantum mechanics. This happens for a large class of quantum systems if embedded into ... More
On the maximum size of an anti-chain of linearly separable sets and convex pseudo-discsJul 02 2007Jan 08 2008We show that the maximum cardinality of an anti-chain composed of intersections of a given set of n points in the plane with half-planes is close to quadratic in n. We approach this problem by establishing the equivalence with the problem of the maximum ... More
A generalization of Gordon's theorem and applications to quasiperiodic Schrödinger operatorsMay 12 2000We prove a criterion for absence of eigenvalues for one-dimensional Schr\"odinger operators. This criterion can be regarded as an $L^1$-version of Gordon's theorem and it has a broader range of application. Absence of eigenvalues is then established for ... More
Droplet states in quantum XXZ spin systems on general graphsDec 29 2017Jan 22 2018We study XXZ spin systems on general graphs. In particular, we describe the formation of droplet states near the bottom of the spectrum in the Ising phase of the model, where the Z-term dominates the XX-term. As key tools we use particle number conservation ... More
On the Ornstein-Zernike equation for stationary cluster processes and the random connection modelJul 11 2016In the first part of this paper we consider a general stationary subcritical cluster model in $\mathbb{R}^d$. The associated pair-connectedness function can be defined in terms of two-point Palm probabilities of the underlying point process. Using Palm ... More
Invariant transports of stationary random measures and mass-stationarityJun 11 2009We introduce and study invariant (weighted) transport-kernels balancing stationary random measures on a locally compact Abelian group. The first main result is an associated fundamental invariance property of Palm measures, derived from a generalization ... More
Effects of Axion-Photon Mixing on Gamma-Ray Spectra from Magnetized Astrophysical SourcesAug 08 2007Astrophysical gamma-ray sources come in a variety of sizes and magnetizations. We deduce general conditions under which gamma-ray spectra from such sources would be significantly affected by axion-photon mixing. We show that, depending on strength and ... More
PeV Neutrinos from Ultra-High-Energy Cosmic RaysJul 24 2014We investigate the possibility that the recently detected TeV-PeV neutrino events by IceCube can originate from extragalactic ultra-high-energy cosmic ray interactions with the cosmic microwave background or the UV/optical/IR background. This is done ... More
Spectral Properties of the Discrete Random Displacement ModelAug 06 2010We investigate spectral properties of a discrete random displacement model, a Schr\"odinger operator on $\ell^2(\Z^d)$ with potential generated by randomly displacing finitely supported single-site terms from the points of a sublattice of $\Z^d$. In particular, ... More
On the difference between real and complex arrangementsFeb 11 1992Let $B$ be an arrangement of linear complex hyperplanes in $C^d$. Then a classical result by Orlik \& Solomon asserts that the cohomology algebra of the complement can be constructed from the combinatorial data that are given by the intersection lattice. ... More
Preisach models of hysteresis driven by Markovian input processesJun 16 2017We study the response of Preisach models of hysteresis to stochastically fluctuating external fields. We perform numerical simulations which indicate that analytical expressions derived previously for the autocorrelation functions and power spectral densities ... More
Cavity-induced temperature control of a two-level systemNov 29 2007We consider a two-level atom interacting with a single mode of the electromagnetic field in a cavity within the Jaynes-Cummings model. Initially, the atom is thermal while the cavity is in a coherent state. The atom interacts with the cavity field for ... More
On negative association of some finite point processes on general state spaces, extended versionMar 26 2018We study negative association (NA) for mixed sampled point processes and show that NA holds for such processes if the random number of points of them fulfills ULC property. We connect NA property of point processes with dcx dependence ordering and show ... More
Escaping Points of the Cosine FamilyFeb 29 2004We study the dynamics of iterated cosine maps $E\colon z \mapsto ae^z+be^{-z},$ with $a,b \in \C\setminus \{0\}$. We show that the points which converge to infinity under iteration are organized in the form of rays and, as in the exponential family, every ... More
On a class of growth-maximal hard-core processesMar 08 2013Generalizing the well-known lilypond model we introduce a growth-maximal hard-core model based on a space-time point process of convex particles. Using a purely deterministic algorithm we prove under fairly general assumptions that the model exists and ... More
Model of a PT symmetric Bose-Einstein condensate in a delta-functions double wellMar 08 2012Mar 16 2012The observation of PT symmetry in a coupled optical wave guide system that involves a complex refractive index has been demonstrated impressively in the experiment by R\"uter el al. (Nat. Phys. 6, 192, 2010). This is, however, only an optical analogue ... More
Recursively-Regular Subdivisions and ApplicationsOct 16 2013Dec 12 2014We generalize regular subdivisions (polyhedral complexes resulting from the projection of the lower faces of a polyhedron) introducing the class of recursively-regular subdivisions. Informally speaking, a recursively-regular subdivision is a subdivision ... More
Linear-Time Algorithms for Maximum-Weight Induced Matchings and Minimum Chain Covers in Convex Bipartite GraphsNov 13 2017A bipartite graph $G=(U,V,E)$ is convex if the vertices in $V$ can be linearly ordered such that for each vertex $u\in U$, the neighbors of $u$ are consecutive in the ordering of $V$. An induced matching $H$ of $G$ is a matching such that no edge of $E$ ... More
Eigenvalue Correlations in Continuum one-dimensional Anderson ModelsNov 24 2007Feb 26 2008The methods used to prove the main result must be incorrect, as they can be used to arrive at a contradiction with previously known results. Thus the paper was withdrawn.
Positivity of Lyapunov exponents for Anderson-type models on two coupled stringsNov 01 2006We study two models of Anderson-type random operators on two deterministically coupled continuous strings. Each model is associated with independent, identically distributed four-by-four symplectic transfer matrices, which describe the asymptotics of ... More
A Continuum Version of the Kunz-Souillard Approach to Localization in One DimensionDec 18 2009We consider continuum one-dimensional Schr\"odinger operators with potentials that are given by a sum of a suitable background potential and an Anderson-type potential whose single-site distribution has a continuous and compactly supported density. We ... More