Results for "Sabine Jansen"

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Cluster expansions with renormalized activities and applications to colloidsMar 05 2019We consider a binary system of small and large objects in the continuous space interacting via a non-negative potential. By integrating over the small objects, the effective interaction between the large ones becomes multi-body. We prove convergence of ... More
On the notion(s) of duality for Markov processesOct 26 2012Feb 17 2014We provide a systematic study of the notion of duality of Markov processes with respect to a function. We discuss the relation of this notion with duality with respect to a measure as studied in Markov process theory and potential theory and give functional ... More
Singularity analysis for heavy-tailed random variablesSep 17 2015May 31 2018We propose a novel complex-analytic method for sums of i.i.d. random variables that are heavy-tailed and integer-valued. The method combines singularity analysis, Lindel\"of integrals, and bivariate saddle points. As an application, we prove three theorems ... More
Fermionic and bosonic Laughlin state on thick cylindersSep 19 2011We investigate a many-body wave function for particles on a cylinder known as Laughlin's function. It is the power of a Vandermonde determinant times a Gaussian. Our main result is: in a many-particle limit, at fixed radius, all correlation functions ... More
Continuum percolation for Gibbsian point processes with attractive interactionsAug 06 2012Aug 30 2012We study the problem of continuum percolation in infinite volume Gibbs measures for particles with an attractive pair potential, with a focus on low temperatures (large $\beta$). The main results are bounds on percolation thresholds $\rho_\pm(\beta)$ ... More
Cluster and virial expansions for the multi-species Tonks gasMar 08 2015Sep 25 2015We consider a mixture of non-overlapping rods of different lengths $\ell_k$ moving in $\mathbb{R}$ or $\mathbb{Z}$. Our main result are necessary and sufficient convergence criteria for the expansion of the pressure in terms of the activities $z_k$ and ... More
Cluster expansions for Gibbs point processesJul 27 2018We provide a sufficient condition for the uniqueness in distribution of Gibbs point processes with non-negative pairwise interaction, together with convergent expansions of the log-Laplace functional, factorial moment densities and factorial cumulant ... More
Mayer and virial series at low temperatureSep 29 2011May 18 2012We analyze the Mayer pressure-activity and virial pressure-density series for a classical system of particles in continuous configuration space at low temperature. Particles interact via a finite range potential with an attractive tail. We propose physical ... More
Graphical representation of certain moment dualities and application to population models with balancing selectionJul 25 2012Feb 21 2013We investigate dual mechanisms for interacting particle systems. Generalizing an approach of Alkemper and Hutzenthaler in the case of coalescing duals, we show that a simple linear transformation leads to a moment duality of suitably rescaled processes. ... More
Wigner crystallization in the quantum 1D jellium at all densitiesJun 28 2013Feb 03 2014The jellium is a model, introduced by Wigner (1934), for a gas of electrons moving in a uniform neutralizing background of positive charge. Wigner suggested that the repulsion between electrons might lead to a broken translational symmetry. For classical ... More
Symmetry breaking in Laughlin's state on a cylinderNov 09 2007Aug 15 2008We investigate Laughlin's fractional quantum Hall effect wave function on a cylinder. We show that it displays translational symmetry breaking in the axial direction for sufficiently thin cylinders. At filling factor 1/p, the period is p times the period ... More
Large deviations for cluster size distributions in a continuous classical many-body systemJul 19 2011Mar 17 2015An interesting problem in statistical physics is the condensation of classical particles in droplets or clusters when the pair-interaction is given by a stable Lennard-Jones-type potential. We study two aspects of this problem. We start by deriving a ... More
Bounds for the adiabatic approximation with applications to quantum computationMar 20 2006Nov 08 2007We present straightforward proofs of estimates used in the adiabatic approximation. The gap dependence is analyzed explicitly. We apply the result to interpolating Hamiltonians of interest in quantum computing.
A note on the uniqueness result for the inverse Henderson problemMar 08 2019The inverse Henderson problem of statistical mechanics concerns classical particles in continuous space which interact according to a pair potential depending on the distance of the particles. Roughly stated, it asks for the interaction potential given ... More
Symmetry breaking in quasi-1D Coulomb systemsAug 22 2010Sep 21 2010Quasi one-dimensional systems are systems of particles in domains which are of infinite extent in one direction and of uniformly bounded size in all other directions, e.g. on a cylinder of infinite length. The main result proven here is that for such ... More
Singularity analysis for heavy-tailed random variablesSep 17 2015Let $\alpha \in (0,1),c>0$ and $G(z) = c\sum_{k=1}^\infty z^k \exp( - k^\alpha)$. We apply complex analysis to determine the asymptotic behavior of the $m$th coefficient of the $n$th power of $G(z)$ when $m,n\to \infty$ with $m \geq n G'(1)/G(1)$ and ... More
Random partitions in statistical mechanicsJan 07 2014Sep 11 2014We consider a family of distributions on spatial random partitions that provide a coupling between different models of interest: the ideal Bose gas; the zero-range process; particle clustering; and spatial permutations. These distributions are invariant ... More
At the Frontier of KnowledgeJan 20 2010At any time, there are areas of science where we are standing at the frontier of knowledge, and can wonder whether we have reached a fundamental limit to human understanding. What is ultimately possible in physics? I will argue here that it is ultimately ... More
Theory and Phenomenology of Spacetime DefectsJan 01 2014Whether or not space-time is fundamentally discrete is of central importance for the development of the theory of quantum gravity. If the fundamental description of space-time is discrete, typically represented in terms of a graph or network, then the ... More
AntigravitationSep 18 2009We discuss why there are no negative gravitational sources in General Relativity and show that it is possible to extend the classical theory such that repulsive gravitational interaction occurs.
Large Extra Dimensions and the Minimal LengthSep 29 2004Sep 29 2004Large extra dimensions lower the Planck scale to values soon accessible. Motivated by String Theory, the models of large extra dimensions predict a vast number of new effects in the energy range of the lowered Planck scale, among them the production of ... More
Running Coupling with Minimal LengthMay 14 2004Nov 06 2004In models with large additional dimensions, the GUT scale can be lowered to values accessible by future colliders. Due to modification of the loop corrections from particles propagating into the extra dimensions, the logarithmic running of the couplings ... More
The de Sitter space-time as attractor solution in higher order gravityJan 25 1995For arbitrary high order of the field equation one can always find examples where the de Sitter space-time is an attractor solution in the set of the spatially flat Friedmann-Robertson-Walker models.
Combinatorics of hexagonal fully packed loop configurationsAug 26 2014In this article, fully packed loop configurations of hexagonal shape (HFPLs) are defined. They generalize triangular fully packed loop configurations. To encode the boundary conditions of an HFPL, a sextuple $(\mathsf{l}_\mathsf{T},\mathsf{t},\mathsf{r}_\mathsf{T};\mathsf{r}_\mathsf{B},\mathsf{b},\mathsf{l}_\mathsf{B})$ ... More
Bohmian transmission and reflection dwell times without trajectory samplingJun 08 2004Jun 02 2005Within the framework of Bohmian mechanics dwell times find a straightforward formulation. The computation of associated probabilities and distributions however needs the explicit knowledge of a relevant sample of trajectories and therefore implies formidable ... More
Triangular fully packed loop configurations of excess 2Jun 02 2015Triangular fully packed loop configurations (TFPLs) came up in the study of fully packed loop configurations on a square (FPLs) corresponding to link patterns with a large number of nested arches. To a TFPL is assigned a triple $(u,v;w)$ of $01$-words ... More
Testing Superdeterministic ConspiracyJan 01 2014Tests of Bell's theorem rule out local hidden variables theories. But any theorem is only as good as the assumptions that go into it, and one of these assumptions is that the experimenter can freely chose the detector settings. Without this assumption, ... More
Gravity can be neither classical nor quantizedDec 03 2012I argue that it is possible for a theory to be neither quantized nor classical. We should therefore give up the assumption that the fundamental theory which describes gravity at shortest distances must either be quantized, or quantization must emerge ... More
Can we measure structures to a precision better than the Planck length?May 16 2012It was recently claimed that the Planck length is not a limit to the precision by which we can measure distances, but that instead it is merely the Planck volume that limits the precision by which we can measure volumes. Here, we investigate this claim ... More
Comments on Nonlocality in Deformed Special Relativity, in reply to arXiv:1004.0664 by Lee Smolin and arXiv:1004.0575 by Jacob et alMay 04 2010It was previously shown that models with deformations of special relativity that have an energy-dependent yet observer-independent speed of light suffer from nonlocal effects that are in conflict with observation to very high precision. In a recent paper ... More
Comment on "No-go theorem for bimetric gravity with positive and negative mass"Sep 11 2009Authors Hohmann and Wohlfarth have put forward a no-go theorem for bimetric gravity with positive and negative mass in arXiv:0908.3384v1 [gr-qc]. This comment shows that their no-go theorem does not apply to arXiv:0807.2838v1 [gr-qc].
Phenomenology of Space-time Imperfection II: Local DefectsSep 02 2013Jan 01 2014We propose a phenomenological model for the scattering of particles on space-time defects in a treatment that maintains Lorentz-invariance on the average. The local defects considered here cause a stochastic violation of momentum conservation. The scattering ... More
What Black Holes Can Teach UsDec 17 2004Black holes merge together different field of physics. From General Relativity over thermodynamics and quantum field theory, they do now also reach into the regime of particle and collider physics. In the presence of additional compactified dimensions, ... More
Search for exotic physics with four-fermion coupling at LEPMay 25 2001Preliminary results of measurements of fermion-pair production at LEP2 are used to derive limits on new physics phenomena. Combinations of the cross sections and asymmetrie of the 4 LEP collaborations are interpreted in terms four-fermion contact interactions, ... More
Local convergence of spectra and pseudospectraMay 03 2016We prove local convergence results for the spectra and pseudospectra of sequences of linear operators acting in different Hilbert spaces and converging in generalised strong resolvent sense to an operator with possibly non-empty essential spectrum. We ... More
White Dwarfs in Globular Clusters - Progenitors, Successors and the Real ThingSep 16 2002I will start by discussing the evolutionary status of the white dwarf *progenitors*, the hot UV bright stars. Observations of UIT-selected UV bright stars in globular clusters suggest that a high percentage of them manage to evolve from the horizontal ... More
Phenomenology of Space-time Imperfection I: Nonlocal DefectsSep 02 2013Jan 01 2014If space-time is emergent from a fundamentally non-geometric theory it will generically be left with defects. Such defects need not respect the locality that emerges with the background. Here, we develop a phenomenological model that parameterizes the ... More
Experimental Search for Quantum GravityOct 17 2010We offer a brief survey of existent and planned experimental tests for quantum gravity. First, we outline the questions we wish to address, and then introduce some of the phenomenological models that are currently used in quantum gravity, both with and ... More
Cluster-Group Interaction in the Virgo ClusterJun 17 2002We present two projects related to interaction in the Virgo cluster. In the first section we draw a quantitative comparison of the distribution of the galaxies and the intra-cluster gas taking into account that the Virgo cluster has an irregular structure ... More
Distant clusters of galaxies: X-ray properties and their relationsAug 12 1999We investigate the evolution of clusters of galaxies in a sample of distant clusters with redshifts between 0.3 and 1.0. We show the abilities and limitations of combined ROSAT and ASCA data to draw cosmological conclusions. For the first time bolometric ... More
X-ray observations of distant lensing clustersJun 24 1997X-ray observations of three clusters are presented: RXJ1347.5-1145, Cl0939+47, and Cl0500-24. Although these clusters are the in same redshift range (0.32 - 0.45) and act all as gravitational lenses, they show very different properties. RXJ1347.5-1145 ... More
Comment on the black hole firewallOct 19 2012Recently, it has been argued that black hole complementarity is inconsistent by showing that, for an infalling observer, it would lead to the existence of a firewall near the black hole horizon, thereby violating the equivalence principle. If true, this ... More
Testing super-deterministic hidden variables theoriesMay 22 2011We propose to experimentally test non-deterministic time evolution in quantum mechanics by consecutive measurements of non-commuting observables on the same prepared state. While in the standard theory the measurement outcomes are uncorrelated, in a super-deterministic ... More
Comment on arXiv:1007.0718 by Lee SmolinAug 07 2010In a recent paper it was suggested a novel interpretation of deformed special relativity. In that new approach, nonlocal effects that had previously been shown to occur and be incompatible with experiment to high precision, are interpreted as coordinate ... More
The Minimal Length and Large Extra DimensionsOct 08 2004Planck scale physics represents a future challenge, located between particle physics and general relativity. The Planck scale marks a threshold beyond which the old description of spacetime breaks down and conceptually new phenomena must appear. Little ... More
The Soccer-Ball ProblemMar 09 2014Jul 29 2014The idea that Lorentz-symmetry in momentum space could be modified but still remain observer-independent has received quite some attention in the recent years. This modified Lorentz-symmetry, which has been argued to arise in Loop Quantum Gravity, is ... More
Minimal Length Scale Scenarios for Quantum GravityMar 28 2012Apr 30 2013We review the question of whether the fundamental laws of nature limit our ability to probe arbitrarily short distances. First, we examine what insights can be gained from thought experiments for probes of shortest distances, and summarize what can be ... More
The Free Will FunctionFeb 03 2012It is argued that it is possible to give operational meaning to free will and the process of making a choice without employing metaphysics.
Simulations of Merging Clusters of GalaxiesSep 30 2000Numerical simulations of cluster mergers reveal many characteristics of the merging process: shock structure and strength, observational signatures of the dynamical state, effects on the mass determination, turbulence and the evolution of the X-ray luminosity ... More
Gas in Groups and Clusters of GalaxiesDec 04 2002Groups and clusters contain a large fraction of hot gas which emits X-ray radiation. This gas yields information on the dynamical state and on the total mass of these systems. X-ray spectra show that heavy elements are present in the gas. As these metals ... More
X-ray and optical observations of three clusters of galaxies: Abell 901, Abell 1437, and Abell 3570Jan 06 2000We analyse three clusters of galaxies, Abell 901 (z=0.17), Abell 1437 (z=0.13) and Abell 3570 (z=0.037). They have low to intermediate X-ray fluxes and an irregular morphology in the ROSAT All-Sky Survey (RASS). These clusters are chosen to test the abilities ... More
The Accuracy of Mass Determination in Galaxy Clusters by X-ray ObservationsMar 09 1995We test the reliability of mass determination in clusters of galaxies by X-ray observations. The true mass in cluster models is compared to the mass derived by the X-ray emission and X-ray temperature of a model assuming hydrostatic equilibrium and spherical ... More
Sums of Hermitian Squares as an Approach to the BMV ConjectureFeb 08 2008May 20 2009Lieb and Seiringer stated in their reformulation of the Bessis-Moussa-Villani (BMV) conjecture that all coefficients of the polynomial p(t)=Tr[(A+tB)^m], where A and B are positive semidefinite matrices of the same size and m an arbitrary integer, are ... More
Measurements of Differential Z/gamma*+jet+X Cross Sections with the D0 DetectorNov 07 2009Nov 11 2009We present measurements of differential cross sections in inclusive Z/gamma* plus jet production in a data sample of 1 fb^{-1} collected with the D0 detector in proton antiproton collisions at sqrt{s} = 1.96 TeV. Measured variables include the Z/gamma* ... More
Using Layout Information for Spreadsheet VisualizationFeb 27 2008This paper extends a spreadsheet visualization technique by using layout information. The original approach identifies logically or semantically related cells by relying exclusively on the content of cells for identifying semantic classes. A disadvantage ... More
A No-go theorem for Poincaré-invariant networksApr 23 2015Oct 01 2015I explain why there are no Poincar\'e-invariant networks with a locally finite distribution of nodes and links in Minkowski-spacetime of any dimension.
Quantum superpositions of the speed of lightJul 04 2012While it has often been proposed that, fundamentally, Lorentz-invariance is not respected in a quantum theory of gravity, it has been difficult to reconcile deviations from Lorentz-invariance with quantum field theory. The most commonly used mechanisms ... More
Comment on arXiv:1104.2019, "Relative locality and the soccer ball problem," by Amelino-Camelia et alFeb 18 2012It is explained why the argument in arXiv:1104.2019 does not answer the question how to describe multi-particle states in models with a deformed Lorentz-symmetry in momentum space.
Bounds on an energy-dependent and observer-independent speed of light from violations of localityApr 03 2010We show that models with deformations of special relativity that have an energy-dependent speed of light have non-local effects. The requirement that the arising non-locality is not in conflict with known particle physics allows us to derive strong bounds ... More
Reply to arXiv:1006.2126 by Giovanni Amelino-Camelia et alJun 23 2010Jul 07 2010It was previously shown that models with deformations of special relativity that have an energy-dependent yet observer-independent speed of light suffer from nonlocal effects that are in conflict with observation to very high precision. In a recent preprint ... More
Comments on and Comments on Comments on Verlinde's paper "On the Origin of Gravity and the Laws of Newton"Mar 04 2010We offer some, hopefully clarifying, comments on Verlinde's recent claim that gravity is an entropic force. A suitable identification of quantities shows that both formulations of Newtonian gravity, the classical and the thermodynamical one, are actually ... More
Functional Renormalization-Group Analysis of Luttinger Liquids with ImpuritiesMar 13 2006In one-dimensional quantum wires the interplay of electron correlations and impurities strongly influences the low-energy physics. The diversity of energy scales and the competition of correlations in interacting Fermi systems can be treated very efficiently ... More
Intra-Cluster Medium Enrichment and the Dynamical State of Galaxy ClustersAug 24 2001The effects of cluster mergers on the metal enrichment of the intra-cluster gas in clusters of galaxies are reviewed. Mergers can influence the metal production as well as the gas ejection processes, which transport the gas from the galaxy potential wells ... More
Clusters of Galaxies: Diagnostic Tools for CosmologyOct 17 2000Clusters of galaxies can be used for very different kinds of cosmological tests. I review a few of the methods: determination of cluster masses and dark matter content, metal enrichment and its connection to the origin of the intra-cluster gas, and the ... More
Clusters of Galaxies: Multifrequency Observations versus TheoriesSep 02 1999Clusters of galaxies are large gravitationally bound systems which consist of several observable components: hundreds of galaxies, hot gas between the galaxies and sometimes relativistic particles. These components are emitting in different wavelengths ... More
Simulations of Clusters of GalaxiesJul 01 2001Numerical simulations of clusters of galaxies provide a unique way to follow the dynamics of these systems. The models reveal many characteristics of the merging process of subclusters: shock structure and strength, temperature distribution and gas distribution. ... More
Metal Enrichment in the Intra-Cluster MediumNov 20 2006The enrichment of the Intra-Cluster Medium (ICM) with heavy elements is reviewed. There is now good observational evidence for enrichment including abundance ratios and metallicity distributions. Various processes involved in the enrichment process -- ... More
Convergence of sequences of linear operators and their spectraApr 26 2016We establish spectral convergence results of approximations of unbounded non-selfadjoint linear operators with compact resolvents by operators that converge in generalized strong resolvent sense. The aim is to establish general assumptions that ensure ... More
Surface energy and boundary layers for a chain of atoms at low temperatureApr 12 2019We analyze the surface energy and boundary layers for a chain of atoms at low temperature for an interaction potential of Lennard-Jones type. The pressure (stress) is assumed small but positive and bounded away from zero, while the temperature $\beta^{-1}$ ... More
Multispecies Virial ExpansionsApr 08 2013Jun 11 2013We study the virial expansion of mixtures of countably many different types of particles. The main tool is the Lagrange-Good inversion formula, which has other applications such as counting coloured trees or studying probability generating functions in ... More
Chiral Fermions, Anomalies and Chern-Simons Currents on the LatticeDec 21 1992I discuss the zeromode spectrum of lattice chiral fermions in the domain wall model suggested recently. In particular I give the critical momenta where the fermions cease to be chiral and show that the spectrum is directly related to the behaviour of ... More
Model revision inference for extensions of first order logicMay 16 2014I am Joachim Jansen and this is my research summary, part of my application to the Doctoral Consortium at ICLP'14. I am a PhD student in the Knowledge Representation and Reasoning (KRR) research group, a subgroup of the Declarative Languages and Artificial ... More
Stochastic equations for a self-regulating geneMar 13 2014Expression of cellular genes is regulated by binding of transcription factors to their promoter, either activating or inhibiting transcription of a gene. Particularly interesting is the case when the expressed protein regulates its own transcription. ... More
Status Report on ILDG activitiesSep 07 2006Oct 05 2006A status report about the International Lattice Data Grid (ILDG) is given. Different countries participating in the ILDG have created regional lattice data grid solutions that are implemented, working and used. The remaining task and the focus of present ... More
Existence of Typical Scales for Manifolds with Lower Ricci Curvature BoundMar 28 2017For collapsing sequences of Riemannian manifolds which satisfy a uniform lower Ricci curvature bound it is shown that there is a sequence of scales such that for a set of good base points of large measure the pointed rescaled manifolds subconverge to ... More
Enron versus EUSES: A Comparison of Two Spreadsheet CorporaMar 13 2015Spreadsheets are widely used within companies and often form the basis for business decisions. Numerous cases are known where incorrect information in spreadsheets has lead to incorrect decisions. Such cases underline the relevance of research on the ... More
Domain Wall Fermions and Chiral Gauge TheoriesOct 26 1994We review the status of the domain wall fermion approach to construct chiral gauge theories on the lattice. In this model an extra, fifth dimension is added and our 4-dimensional world lives on a domainwall induced by a soliton shaped mass defect that ... More
Recent Developments in Fermion Simulation AlgorithmsJul 23 1996A summary of recent developments in the field of simulation algorithms for dynamical fermions is given.
Actions for dynamical fermion simulations: are we ready to go?Nov 26 2003A critical review, playing devil's advocate, on present dynamical fermion simulations is given.
Resolution studies with the DATURA beam telescopeOct 08 2016Nov 07 2016Detailed studies of the resolution of a EUDET-type beam telescope are carried out using the DATURA beam telescope as an example. The EUDET-type beam telescopes make use of CMOS MIMOSA 26 pixel detectors for particle tracking allowing for precise characterisation ... More
Structure Functions on the latticeOct 24 2000We report on a lattice computation of the second moment of the pion matrix element of the twist-2 non-singlet operator corresponding to the average momentum of parton densities. We apply a fully non-perturbatively evaluated running renormalization constant ... More
Status of the Finite Temperature Electroweak Phase Transition on the LatticeSep 11 1995I review the status of non-perturbative investigations of the finite temperature electroweak phase transition by means of lattice simulations.
Notes on Pointed Gromov-Hausdorff ConvergenceMar 28 2017The present article addresses to everyone who starts working with (pointed) Gromov-Hausdorff convergence. In the major part, both Gromov-Hausdorff convergence of compact and of pointed metric spaces are introduced and investigated. Moreover, the relation ... More
Radiation damage of the ILC positron source targetDec 14 2007The radiation damage of the positron source target for the International Linear Collider (ILC) has been studied. The displacement damage in target material due to multi-MeV photons has been calculated by combining FLUKA simulations for secondary particle ... More
Remarks on the convergence of pseudospectraAug 14 2014We establish the convergence of pseudospectra in Hausdorff distance for closed operators acting in different Hilbert spaces and converging in the generalised norm resolvent sense. As an assumption, we exclude the case that the limiting operator has constant ... More
Non-Axisymmetric Flows on Hot Jupiters with Oblique Magnetic FieldsAug 06 2014Giant planets that reside in close proximity to their host stars are subject to extreme irradiation, which gives rise to thermal ionization of trace Alkali metals in their atmospheres. On objects where the atmospheric electrical conductivity is substantial, ... More
Conductance Through a Redox System in the Coulomb Blockade Regime: Many-Particle Effects and Influence of Electronic CorrelationsNov 27 2009We investigate the transport characteristics of a redox system weakly coupled to leads in the Coulomb blockade regime. The redox system comprises a donor and acceptor separated by an insulating bridge in a solution. It is modeled by a two-site extended ... More
Asymmetric jet cuts in dijet measurements at ZEUSApr 11 2002Asymmetric jet transverse energy cuts are now commonly used for dijet analyses currently performed in the Breit Frame at ZEUS. I will discuss the motivation for these cuts and present the results of studies identifying unphysical behavior in the theroretically ... More
Collective dynamics of dipolar and multipolar colloids: from passive to active systemsJan 30 2016This article reviews recent research on the collective dynamical behavior of colloids with dipolar or multipolar interactions. Indeed, whereas equilibrium structures and static self-assembly of such systems are now rather well understood, the past years ... More
Interplay of Direct and Indirect Searches for New PhysicsOct 17 2011We report recent work on the interplay of collider and flavour physics regarding the search for physics beyond the Standard Model.
Combining Inclusion Polymorphism and Parametric PolymorphismJun 14 1999We show that the question whether a term is typable is decidable for type systems combining inclusion polymorphism with parametric polymorphism provided the type constructors are at most unary. To prove this result we first reduce the typability problem ... More
Collider signatures of gravitino dark matter with a sneutrino NLSPMar 12 2007Aug 06 2007For gravitino dark matter with conserved R-parity and mass in the GeV range, very strong constraints from Big Bang Nucleosynthesis exclude the popular NLSP candidates like neutralino and charged sleptons. In this letter we therefore draw attention to ... More
Quantum dynamics of trapped ions in a dynamic field gradient using dressed statesJun 15 2016Novel ion traps that provide either a static or a dynamic magnetic gradient field allow for the use of radio frequency (rf) radiation for coupling internal and motional states of ions, which is essential for conditional quantum logic. We show that the ... More
Phenomenological Quantum GravityNov 14 2009If the history of science has taught us anything, it's that persistence and creativity makes the once impossible possible. It has long been thought experimental tests of quantum gravity are impossible. But during the last decade, several different approaches ... More
A first XMM-Newton look at the most X-ray-luminous galaxy cluster RX J1347.5-1145Dec 09 2004We present the first results from an XMM-Newton observation of RX J1347.5-1145 (z=0.451), the most luminous X-ray cluster of galaxies currently known, with a luminosity L_X = 6.0 \pm 0.1 \times 10^{45} erg/s in the [2-10] keV energy band. The cluster ... More
The Casimir Effect in the Presence of a Minimal LengthFeb 15 2005Mar 15 2005Large extra dimensions lower the Planck scale to values soon accessible. Not only is the Planck scale the energy scale at which effects of modified gravity become important. The Planck length also acts as a minimal length in nature, providing a natural ... More
The effect of magnetic fields on the mass determination of clusters of galaxiesOct 16 2000We test the effects of magnetic fields on the mass determination of galaxy clusters with the X-ray method. As this method takes into account only thermal pressure, additional non-thermal pressure support, e.g. caused by a magnetic field, can result in ... More
Gas Dynamic Stripping and X-Ray Emission of Cluster Elliptical GalaxiesFeb 12 2001Detailed 3-D numerical simulations of an elliptical galaxy orbiting in a gas-rich cluster of galaxies indicate that gas dynamic stripping is less efficient than the results from previous, simpler calculations (Takeda et al. 1984; Gaetz et al. 1987) implied. ... More
Structural Relaxation and Mode Coupling in a Simple Liquid: Depolarized Light Scattering in BenzeneApr 08 2002Apr 18 2002We have measured depolarized light scattering in liquid benzene over the whole accessible temperature range and over four decades in frequency. Between 40 and 180 GHz we find a susceptibility peak due to structural relaxation. This peak shows stretching ... More
Characterizing the width of entanglementJul 26 2015Sep 06 2016We introduce the concept of entanglement width as measure of the spatial distribution of entanglement in multiparticle systems. We develop criteria to detect the width of entanglement using global observables such as energy and magnetic susceptibility. ... More