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Center-Excised X-ray Luminosity as an Efficient Mass Proxy for Future Galaxy Cluster SurveysMay 25 2017Oct 26 2017The cosmological constraining power of modern galaxy cluster catalogs can be improved by obtaining low-scatter mass proxy measurements for even a small fraction of sources. In the context of large upcoming surveys that will reveal the cluster population ... More

Radio loud AGN and the L_X - σrelation of galaxy groups and clustersNov 19 2007Jun 23 2008We use the ROSAT All-Sky Survey to study the X-ray properties of a sample of 625 groups and clusters of galaxies selected from the Sloan Digital Sky Survey. We stack clusters with similar velocity dispersions and investigate whether their average X-ray ... More

Cosmology and Astrophysics from Relaxed Galaxy Clusters I: Sample SelectionFeb 20 2015This is the first in a series of papers studying the astrophysics and cosmology of massive, dynamically relaxed galaxy clusters. Here we present a new, automated method for identifying relaxed clusters based on their morphologies in X-ray imaging data. ... More

New constraints on $f(R)$ gravity from clusters of galaxiesNov 29 2014Aug 08 2015The abundance of massive galaxy clusters is a powerful probe of departures from General Relativity (GR) on cosmic scales. Despite current stringent constraints placed by stellar and galactic tests, on larger scales alternative theories of gravity such ... More

Weighing the Giants V: Galaxy Cluster Scaling RelationsJun 10 2016Sep 26 2016We present constraints on the scaling relations of galaxy cluster X-ray luminosity, temperature and gas mass (and derived quantities) with mass and redshift, employing masses from robust weak gravitational lensing measurements. These are the first such ... More

The evolution of the density of galaxy clusters and groups: denser environments at higher redshiftsFeb 18 2010We show that, observationally, the projected local density distribution in high-z clusters is shifted towards higher values compared to clusters at lower redshift. To search for the origin of this evolution, we analyze a sample of haloes selected from ... More

The accretion histories of brightest cluster galaxies from their stellar population gradientsMar 04 2015We analyse the spatially-resolved stellar populations of 9 local ($z<0.1$) Brightest Cluster Galaxies (BCGs) observed with VIMOS in IFU mode. Our sample is composed of 7 slow-rotating and 2 fast-rotating BCGs. We do not find a connection between stellar ... More

The Grism lens-amplified survey from space (GLASS). VIII. The influence of the cluster properties on Halpha emitter galaxies at 0.3<z<0.7Oct 14 2016Exploiting the data of the Grism Lens-Amplified Survey from Space (GLASS), we characterize the spatial distribution of star formation in 76 galaxies in 10 clusters at 0.3< z <0.7. In a companion paper we contrast the properties of field and cluster galaxies, ... More

Extreme AGN Feedback and Cool Core Destruction in the X-ray Luminous Galaxy Cluster MACS J1931.8-2634Oct 01 2010Oct 05 2010We report on a deep, multiwavelength study of the galaxy cluster MACS J1931.8-2634 using Chandra X-ray, Subaru optical, and VLA 1.4 GHz radio data. This cluster (z=0.352) harbors one of the most X-ray luminous cool cores yet discovered, with an equivalent ... More

Weighing the Giants - III. Methods and Measurements of Accurate Galaxy Cluster Weak-Lensing MassesAug 02 2012Apr 18 2014We report weak-lensing masses for 51 of the most X-ray luminous galaxy clusters known. This cluster sample, introduced earlier in this series of papers, spans redshifts 0.15 < z_cl < 0.7, and is well suited to calibrate mass proxies for current cluster ... More

The Grism lens-amplified survey from space (GLASS). VIII. The influence of the cluster properties on Halpha emitter galaxies at 0.3<z<0.7Oct 14 2016Feb 18 2017Exploiting the data of the Grism Lens-Amplified Survey from Space (GLASS), we characterize the spatial distribution of star formation in 76 high star forming galaxies in 10 clusters at 0.3< z <0.7. All these galaxies are likely restricted to first infall. ... More

The build-up of the colour-magnitude relation in galaxy clusters since z~0.8Oct 12 2006Oct 18 2006Using galaxy clusters from the ESO Distant Cluster Survey, we study how the distribution of galaxies along the colour-magnitude relation has evolved since z~0.8. While red-sequence galaxies in all these clusters are well described by an old, passively ... More

Current characteristics of a one-dimensional Hubbard chain: The role of correlation and dissipationJun 16 2015We study the electronic transport in an infinite one-dimensional Hubbard chain, driven by a homogeneous electric field. The physical chain is coupled to fermion bath chains, in order to account for dissipation and to prevent the occurrence of Bloch Oscillations. ... More

Precise weak lensing constraints from deep high-resolution $K_\mathrm{s}$ images: VLT/HAWK-I analysis of the super-massive galaxy cluster RCS2$J$232727.7$-$020437 at $z=0.70$Nov 01 2017Apr 04 2018We demonstrate that deep good-seeing VLT/HAWK-I $K_\mathrm{s}$ images complemented with $g$+$z$-band photometry can yield a sensitivity for weak lensing studies of massive galaxy clusters at redshifts \mbox{$0.7\lesssim z \lesssim 1.1$}, which is almost ... More

Spitzer UltRa Faint SUrvey Program (SURFS UP). II. IRAC-Detected Lyman-Break Galaxies at 6 < z < 10 Behind Strong-Lensing ClustersApr 08 2015Jan 05 2016We study the stellar population properties of the IRAC-detected $6 \lesssim z \lesssim 10$ galaxy candidates from the Spitzer UltRa Faint SUrvey Program (SURFS UP). Using the Lyman Break selection technique, we find a total of 16 new galaxy candidates ... More

Evolution of the Early-Type Galaxy Fraction in Clusters since z = 0.8Oct 08 2009We study the morphological content of a large sample of high-redshift clusters to determine its dependence on cluster mass and redshift. Quantitative morphologies are based on bulge+disk decompositions of cluster and field galaxies on deep VLT/FORS2 images ... More

The environments of starburst and post-starburst galaxies at z=0.4-0.8Nov 03 2008Nov 07 2008Post-starburst (E+A or k+a) spectra, characterized by their exceptionally strong Balmer lines in absorption and the lack of emission lines, belong to galaxies in which the star formation activity ended abruptly sometime during the past Gyr. We perform ... More

Spectroscopy of clusters in the ESO distant cluster survey (EDisCS).II. Redshifts, velocity dispersions, and substructure for clusters in the last 15 fieldsFeb 01 2008AIMS. We present spectroscopic observations of galaxies in 15 survey fields as part of the ESO Distant Cluster Survey (EDisCS). We determine the redshifts and velocity dispersions of the galaxy clusters located in these fields, and we test for possible ... More

Effective spinless fermions in the strong coupling Kondo modelJun 05 2002Nov 21 2002Starting from the two-orbital Kondo-lattice model with classical t_2g spins, an effective spinless fermion model is derived for strong Hund coupling J_H with a projection technique. The model is studied by Monte Carlo simulations and analytically using ... More

Non-equilibrium Green's functions and their relation to the negative differential conductance in the interacting resonant level modelDec 20 2018Jan 23 2019We evaluate the non-equilibrium single particle Green's functions in the steady state of the interacting resonant level model (IRLM) under the effect of an applied bias voltage. Employing the so-called auxiliary master equation approach, we present accurate ... More

Charge redistribution in correlated heterostuctures within nonequilibrium real-space dynamical mean-field theoryMay 02 2018Aug 13 2018We address the steady-state behavior of a system consisting of several correlated monoatomic layers sandwiched between two metallic leads under the influence of a bias voltage. In particular, we investigate the effect of the local Hubbard and of the long-range ... More

Accurate bare susceptibilities from full-potential $\textit{ab initio}$ calculationsJul 13 2014Sep 26 2014Electronic susceptibilities are a very popular tool to study electronic and magnetic properties of materials, both in experiment and theory. Unfortunately, the numerical evaluation of even the bare susceptibility, which depends on the computation of matrix ... More

Nonequilibrium, spatio-temporal formation of the Kondo screening-cloud on a latticeSep 02 2014Mar 03 2015We study the nonequilibrium formation of a spin screening cloud that accompanies the quenching of a local magnetic moment immersed in a Fermi sea at zero temperature. Based on high precision density matrix renormalization group results for the interacting ... More

Emission characteristics of laser-driven dissipative coupled-cavity systemsNov 11 2010Feb 25 2011We consider a laser-driven and dissipative system of two coupled cavities with Jaynes-Cummings nonlinearity. In particular, we investigate both incoherent and coherent laser driving, corresponding to different experimental situations. We employ Arnoldi ... More

Analysis of femtosecond pump-probe photoelectron-photoion coincidence measurements applying Bayesian probability theorySep 13 2017Jun 08 2018Ultrafast dynamical processes in photoexcited molecules can be observed with pump-probe measurements, in which information about the dynamics is obtained from the transient signal associated with the excited state. Background signals provoked by pump ... More

Simplicial homotopy in semi-abelian categoriesJul 04 2006We study Quillen's model category structure for homotopy of simplicial objects in the context of Janelidze, Marki and Tholen's semi-abelian categories. This model structure exists as soon as the base category A is regular Mal'tsev and has enough regular ... More

Homology and homotopy in semi-abelian categoriesJul 04 2006The theory of abelian categories proved very useful, providing an axiomatic framework for homology and cohomology of modules over a ring and, in particular, of abelian groups. For many years, a similar categorical framework has been lacking for non-abelian ... More

Multiple Images of a Highly Magnified Supernova Formed by an Early-Type Cluster Galaxy LensNov 21 2014Mar 05 2015In 1964, Refsdal hypothesized that a supernova whose light traversed multiple paths around a strong gravitational lens could be used to measure the rate of cosmic expansion. We report the discovery of such a system. In Hubble Space Telescope imaging, ... More

The ESO Distant Cluster Sample: galaxy evolution and environment out to z=1Apr 29 2009The ESO Distant Cluster Survey (EDisCS, P.I. Simon D.M. White, LP 166.A-0162) is an ESO large programme aimed at studying clusters and cluster galaxies at z=0.4-1. How different is the evolution of the star formation activity in clusters, in groups and ... More

The Mochi.LabJet experiment for measurements of canonical helicity injection in a laboratory astrophysical jetNov 20 2017Mar 29 2018The Mochi device is a new pulsed power plasma experiment designed to produce long, collimated, stable, magnetized plasma jets when set up in the LabJet configuration. The LabJet configuration aims to simulate an astrophysical jet in the laboratory by ... More

Bayesian Analysis of Femtosecond Pump-Probe Photoelectron-Photoion Coincidence Spectra with Fluctuating Laser IntensitiesJan 21 2019This paper employs Bayesian probability theory for analyzing data generated in femtosecond pump-probe photoelectron-photoion coincidence (PEPICO) experiments. These experiments allow investigating ultrafast dynamical processes in photoexcited molecules. ... More

Scientific Synergy Between LSST and EuclidOct 23 2017Nov 29 2017Euclid and the Large Synoptic Survey Telescope (LSST) are poised to dramatically change the astronomy landscape early in the next decade. The combination of high cadence, deep, wide-field optical photometry from LSST with high resolution, wide-field optical ... More

WFIRST Science Investigation Team "Cosmology with the High Latitude Survey" Annual Report 2017Apr 10 2018Cosmic acceleration is the most surprising cosmological discovery in many decades. Testing and distinguishing among possible explanations requires cosmological measurements of extremely high precision probing the full history of cosmic expansion and structure ... More

Concerning the Neural CodeNov 03 2018The central problem with understanding brain and mind is the neural code issue: understanding the matter of our brain as basis for the phenomena of our mind. The richness with which our mind represents our environment, the parsimony of genetic data, the ... More

Measuring cosmic distances with galaxy clustersJul 30 2013In addition to cosmological tests based on the mass function and clustering of galaxy clusters, which probe the growth of cosmic structure, nature offers two independent ways of using clusters to measure cosmic distances. The first uses measurements of ... More

Pathwise Uniqueness for SDEs with Singular Drift and Nonconstant Diffusion: A simple proofAug 30 2018A new proof of pathwise uniqueness for SDEs with Sobolev diffusion and integrable drift term is introduced by extending a method from E. Fedrizzi and F. Flandoli (Pathwise uniqueness and continuous dependence of SDEs with non-regular drift, Stochastics ... More

X-ray Bright Active Galactic Nuclei in Massive Galaxy Clusters II: The Fraction of Galaxies Hosting Active NucleiOct 21 2013We present a measurement of the fraction of cluster galaxies hosting X-ray bright Active Galactic Nuclei (AGN) as a function of clustercentric distance scaled in units of $r_{500}$. Our analysis employs high quality Chandra X-ray and Subaru optical imaging ... More

The ternary commutator obstruction for internal crossed modulesJul 05 2011Jun 19 2012In finitely cocomplete homological categories, co-smash products give rise to (possibly higher-order) commutators of subobjects. We use binary and ternary co-smash products and the associated commutators to give characterisations of internal crossed modules ... More

The Yoneda isomorphism commutes with homologyMay 20 2015Sep 06 2015We show that, for a right exact functor from an abelian category to abelian groups, Yoneda's isomorphism commutes with homology and, hence, with functor derivation. Then we extend this result to semiabelian domains. An interpretation in terms of satellites ... More

A note on split extensions of bialgebrasJan 03 2017Mar 13 2017We prove a universal characterization of Hopf algebras among cocommutative bialgebras over a field: a cocommutative bialgebra is a Hopf algebra precisely when every split extension over it admits a join decomposition. We also explain why this result cannot ... More

Further remarks on the "Smith is Huq" conditionJan 22 2014We compare the 'Smith is Huq' condition (SH) with three commutator conditions in semi-abelian categories: first an apparently weaker condition which arose in joint work with Bourn and turns out to be equivalent with (SH), then an apparently equivalent ... More

Categories vs. groupoids via generalised Mal'tsev propertiesJun 13 2012Aug 18 2014We study the difference between internal categories and internal groupoids in terms of generalised Mal'tsev properties---the weak Mal'tsev property on the one hand, and $n$-permutability on the other. In the first part of the article we give conditions ... More

A comonadic interpretation of Baues-Ellis homology of crossed modulesMay 20 2018We introduce and study a homology theory of crossed modules with coefficients in an abelian crossed module. We discuss the basic properties of these new homology groups and give some applications. We then restrict our attention to the case of integral ... More

A note on the "Smith is Huq" conditionJun 09 2010We show that two known conditions which arose naturally in commutator theory and in the theory of internal crossed modules coincide: every star-multiplicative graph is multiplicative if and only if every two effective equivalence relations commute as ... More

A characterisation of Lie algebras amongst anti-commutative algebrasJan 19 2017Jan 23 2019Let $\mathbb{K}$ be an infinite field. We prove that if a variety of anti-commutative $\mathbb{K}$-algebras - not necessarily associative, where $xx=0$ is an identity - is locally algebraically cartesian closed, then it must be a variety of Lie algebras ... More

Galois theory and commutatorsApr 04 2011We prove that the relative commutator with respect to a subvariety of a variety of Omega-groups introduced by the first author can be described in terms of categorical Galois theory. This extends the known correspondence between the Froehlich-Lue and ... More

Approximate Hagemann-Mitschke co-operationsMay 06 2013We show that varietal techniques based on the existence of operations of a certain arity can be extended to n-permutable categories with binary coproducts. This is achieved via what we call approximate Hagemann-Mitschke co-operations, a generalisation ... More

Maximizing Science in the Era of LSST: A Community-Based Study of Needed US CapabilitiesOct 05 2016The Large Synoptic Survey Telescope (LSST) will be a discovery machine for the astronomy and physics communities, revealing astrophysical phenomena from the Solar System to the outer reaches of the observable Universe. While many discoveries will be made ... More

The nature of filamentary cold gas in the core of the Virgo ClusterNov 28 2012Mar 06 2013We present a multi-wavelength study of the emission-line nebulae located southeast of the nucleus of M87, the central dominant galaxy of the Virgo Cluster. We report the detection of far-infrared (FIR) [CII] line emission from the nebulae using observations ... More

An observation on n-permutabilityJun 27 2013We prove that in a regular category all reflexive and transitive relations are symmetric if and only if every internal category is an internal groupoid. In particular, these conditions hold when the category is n-permutable for some n.

A framework for torsion theory computations on elliptic threefoldsSep 27 2018We give a list of statements on the geometry of elliptic threefolds phrased only in the language of topology and homological algebra. Using only notions from topology and homological algebra, we recover existing results and prove new results on torsion ... More

A criterion for reflectiveness of normal extensionsFeb 08 2016We give a new sufficient condition for the normal extensions in an admissible Galois structure to be reflective. We then show that this condition is indeed fulfilled when X is the (protomodular) reflective subcategory of S-special objects of a Barr-exact ... More

Sunspot number second differences as a precursor of the following 11-year sunspot cycleDec 15 2017Forecasting the strength of the sunspot cycle is highly important for many space weather applications. Our previous studies have shown the importance of sunspot number variability in the declining phase of the current 11-year sunspot cycle to predict ... More

Two characterisations of groups amongst monoidsJun 28 2016Apr 26 2017The aim of this paper is to solve a problem proposed by Dominique Bourn: to provide a categorical-algebraic characterisation of groups amongst monoids and of rings amongst semirings. In the case of monoids, our solution is given by the following equivalent ... More

Recent Developments of NEMO: Detection of Solar Eruptions CharacteristicsMar 23 2011The recent developments in space instrumentation for solar observations and telemetry have caused the necessity of advanced pattern recognition tools for the different classes of solar events. The Extreme ultraviolet Imaging Telescope (EIT) of solar corona ... More

Do $n$-Lie algebras have universal enveloping algebrasAug 27 2015The aim of this paper is to investigate in which sense, for $n\geq 3$, $n$-Lie algebras admit universal enveloping algebras. There have been some attempts at a construction (see [10] and [5]) but after analysing those we come to the conclusion that they ... More

Higher Hopf formulae for homology via Galois TheoryJan 29 2007May 21 2007We use Janelidze's Categorical Galois Theory to extend Brown and Ellis's higher Hopf formulae for homology of groups to arbitrary semi-abelian monadic categories. Given such a category A and a chosen Birkhoff subcategory B of A, thus we describe the Barr-Beck ... More

Tangent-point repulsive potentials for a class of non-smooth $m$-dimensional sets in $\R^n$. Part I: Smoothing and self-avoidance effectsFeb 17 2011We consider repulsive potential energies $\E_q(\Sigma)$, whose integrand measures tangent-point interactions, on a large class of non-smooth $m$-dimensional sets $\Sigma$ in $\R^n.$ Finiteness of the energy $\E_q(\Sigma)$ has three sorts of effects for ... More

Octupolar out-of-plane magnetic field structure generation during collisionless magnetic reconnection in a stressed X-point collapseJun 16 2014The out-of-plane magnetic field, generated by fast magnetic reconnection, during collisionless, stressed $X$-point collapse, was studied with a kinetic, 2.5D, fully electromagnetic, relativistic particle-in-cell numerical code, using both closed (flux ... More

The effect of guide-field and boundary conditions on collisionless magnetic reconnection in a stressed X-point collapseDec 18 2013Works of D. Tsiklauri, T. Haruki, Phys. of Plasmas, 15, 102902 (2008) and D. Tsiklauri and T. Haruki, Phys. of Plasmas, 14, 112905, (2007) are extended by inclusion of the out-of-plane magnetic (guide) field. In particular, magnetic reconnection during ... More

State-dependence of climate sensitivity: attractor constraints and palaeoclimate regimesApr 12 2016Equilibrium climate sensitivity is a frequently used measure to predict long-term climate change. However, both climate models and observational data suggest a rather large uncertainty on climate sensitivity (CS). The reasons for this include: the climate ... More

Symmetric critical knots for O'Hara's energiesSep 20 2017We prove the existence of symmetric critical torus knots for O'Hara's knot energy family $E_\alpha$, $\alpha\in (2,3)$ using Palais' classic principle of symmetric criticality. It turns out that in every torus knot class there are at least two smooth ... More

Plateau's problem in Finsler 3-spaceSep 11 2012We explore a connection between the Finslerian area functional based on the Busemann-Hausdorff-volume form, and well-investigated Cartan functionals to solve Plateau's problem in Finsler 3-space, and prove higher regularity of solutions. Free and semi-free ... More

Tangent-point self-avoidance energies for curvesJun 23 2010Jul 05 2010We study a two-point self-avoidance energy $E_q$ which is defined for all rectifiable curves in $R^n$ as the double integral along the curve of $1/r^q$. Here $r$ stands for the radius of the (smallest) circle that is tangent to the curve at one point ... More

Integral Menger curvature for surfacesNov 11 2009Nov 18 2009We develop the concept of integral Menger curvature for a large class of nonsmooth surfaces. We prove uniform Ahlfors regularity and a $C^{1,\lambda}$-a-priori bound for surfaces for which this functional is finite. In fact, it turns out that there is ... More

The Wide Field Infrared Survey Telescope: 100 Hubbles for the 2020sFeb 14 2019The Wide Field Infrared Survey Telescope (WFIRST) is a 2.4m space telescope with a 0.281 deg^2 field of view for near-IR imaging and slitless spectroscopy and a coronagraph designed for > 10^8 starlight suppresion. As background information for Astro2020 ... More

Cluster Galaxies Die HardDec 14 2009Apr 16 2010We investigate how the specific star formation rates of galaxies of different masses depend on cluster-centric radius and on the central/satellite dichotomy in both field and cluster environments. Recent data from a variety of sources, including the cluster ... More

How special are Brightest Group and Cluster Galaxies?Nov 07 2006May 07 2007We use the Sloan Digital Sky Survey to construct a sample of 625 brightest group and cluster galaxies (BCGs) together with control samples of non-BCGs matched in stellar mass, redshift, and color. We investigate how the systematic properties of BCGs depend ... More

The UV-optical colours of brightest cluster galaxies in optically and X-ray selected clustersSep 07 2009Sep 08 2009Many brightest cluster galaxies (BCGs) at the centers of X-ray selected clusters exhibit clear evidence for recent star formation. However, studies of BCGs in optically-selected clusters show that star formation is not enhanced when compared to control ... More

Star formation and AGN activity in SDSS cluster galaxiesSep 18 2009We investigate the recent and current star formation activity of galaxies as function of distance from the cluster center in a sample of 521 SDSS clusters at z<0.1. We show that when the BCGs are excluded from the galaxy sample, there is no evidence for ... More

Cold dark energy constraints from the abundance of galaxy clustersJan 25 2017Nov 22 2017We constrain cold dark energy of negligible sound speed using galaxy cluster abundance observations. In contrast to standard quasi-homogeneous dark energy, negligible sound speed implies clustering of the dark energy fluid at all scales, allowing us to ... More

Optical & Sunyaev-Zel'dovich Observations of a New Sample of Distant Rich Galaxy Clusters in the ROSAT All Sky SurveyDec 10 2014Jun 03 2015Finding a sample of the most massive clusters with redshifts $z>0.6$ can provide an interesting consistency check of the $\Lambda$ cold dark matter ($\Lambda$CDM) model. Here we present results from our search for clusters with $0.6\lesssim z\lesssim1.0$ ... More

The origin of cold gas in giant elliptical galaxies and its role in fueling radio-mode AGN feedbackOct 21 2013Jan 13 2014We present a multi-wavelength study of the interstellar medium in eight nearby, X-ray and optically bright, giant elliptical galaxies. Using Herschel PACS, we map the cold gas in the lines of [CII], [OI], and [OIb]. Additionally, we present Ha+[NII] imaging ... More

The Grism Lens-Amplified Survey from Space (GLASS). I. Survey overview and first data releaseSep 01 2015Sep 04 2015We give an overview of the Grism Lens Amplified Survey from Space (GLASS), a large Hubble Space Telescope program aimed at obtaining grism spectroscopy of the fields of ten massive clusters of galaxies at redshift z=0.308-0.686, including the Hubble Frontier ... More

Galaxy Cluster Mass Reconstruction Project - IV. Understanding the effects of imperfect membership on cluster mass estimationJun 08 2018Aug 16 2018The primary difficulty in measuring dynamical masses of galaxy clusters from galaxy data lies in the separation between true cluster members from interloping galaxies along the line of sight. We study the impact of membership contamination and incompleteness ... More

Measuring the Stellar Masses of z~7 Galaxies with Spitzer Ultrafaint Survey Program (SURFS UP)Apr 01 2014We present Spitzer/IRAC observations of nine $z'$-band dropouts highly magnified (2<mu<12) by the Bullet Cluster. We combine archival imaging with our Exploratory program (SURFS UP), which results in a total integration time of ~30 hr per IRAC band. We ... More

Feasibility Study of Internal Conversion Electron Spectroscopy of $^{229m}$ThFeb 01 2017With an expected energy of 7.8(5) eV, the isomeric first excited state in $^{229}$Th exhibits the lowest excitation energy of all known nuclei. Until today, a value for the excitation energy has been inferred only by indirect measurements. In this paper, ... More

Prony's method on the sphereMar 07 2016Eigenvalue analysis based methods are well suited for the reconstruction of finitely supported measures from their moments up to a certain degree. We give a precise description when Prony's method succeeds in terms of an interpolation condition. In particular, ... More

Characterizing $W^{2,p}$~submanifolds by $p$-integrability of global curvaturesMar 21 2012Oct 20 2012We give sufficient and necessary geometric conditions, guaranteeing that an immersed compact closed manifold $\Sigma^m\subset \R^n$ of class $C^1$ and of arbitrary dimension and codimension (or, more generally, an Ahlfors-regular compact set $\Sigma$ ... More

Interference of Higgs boson resonances in mu^+ mu^- -> neutralino_i neutralino_j with longitudinal beam polarizationJul 05 2004Oct 21 2004We study the interference of resonant Higgs boson exchange in neutralino production in \mu^+ \mu^- annihilation with longitudinally polarized beams. We use the energy distribution of the decay lepton in the process \neutralino_j \to \ell^\pm \slepton^\mp ... More

Compactness and isotopy finiteness for submanifolds with uniformly bounded geometric curvature energiesApr 17 2015Oct 02 2015In this paper, we establish compactness for various geometric curvature energies including integral Menger curvature, and tangent-point repulsive potentials, defined a priori on the class of compact, embedded $m$-dimensional Lipschitz submanifolds in ... More

Response maxima in modulated turbulenceMay 23 2003Isotropic and homogeneous turbulence driven by an energy input modulated in time is studied within a variable range mean-field theory. The response of the system, observed in the second order moment of the large-scale velocity difference D(L,t)=<<(\u(x+L)-\u(x))^2>>~Re(t)^2$, ... More

Response maxima in modulated turbulence Part II: Numerical simulationsMay 23 2003Numerical simulations of fully developed turbulence driven by a modulated energy input rate or driving force are performed within two dynamical cascade models, the GOY shell model and a reduced wave vector set approximation of the Navier-Stokes equation ... More

Elasticity of cross-linked semiflexible biopolymers under tensionMay 05 2013Aiming at the mechanical properties of cross-linked biopolymers, we set up and analyze a model of two weakly bending wormlike chains subjected to a tensile force, with regularly spaced inter-chain bonds (cross-links) represented by harmonic springs. Within ... More

Chaotic and non-chaotic response to quasiperiodic forcing: limits to predictability of ice ages paced by Milankovitch forcingApr 23 2018Aug 16 2018It is well known that periodic forcing of a nonlinear system, even of a two-dimensional autonomous system, can produce chaotic responses with sensitive dependence on initial conditions if the forcing induces sufficient stretching and folding of the phase ... More

Lifetime measurement of the $^{229}$Th nuclear isomerJan 16 2018The first excited isomeric state of $^{229}$Th possesses the lowest energy among all known excited nuclear states. The expected energy is accessible with today's laser technology and in principle allows for a direct optical laser excitation of the nucleus. ... More

The elastic trefoil is the twice covered circleOct 21 2015May 09 2016We investigate the elastic behavior of knotted loops of springy wire. To this end we minimize the classic bending energy $E_{\text{bend}}=\int\kappa^2$ together with a small multiple of ropelength $\mathcal R=\text{length}/\text{thickness}$ in order to ... More

From continuum mechanics to SPH particle systems and back: Systematic derivation and convergenceJan 19 2015Feb 13 2016In this paper, we derive from the principle of least action the equation of motion for a continuous medium with regularized density field in the context of measures. The eventual equation of motion depends on the order in which regularization and the ... More

Test of the Wiedemann-Franz law in an optimally-doped cuprateApr 04 2003May 05 2004We present a study of heat and charge transport in Bi$_{2+x}$Sr$_{2-x}$CuO$_{6+\delta}$ focused on the size of the low-temperature linear term of the thermal conductivity at optimal doping level. In the superconducting state, the magnitude of this term ... More

Interrupted Motility Induced Phase Separation in Aligning Active ColloidsFeb 21 2019Switching on high activity in a relatively dense system of active Janus colloids, we observe fast clustering, followed by cluster aggregation towards full phase separation. The phase separation process is however interrupted when large enough clusters ... More

Push Forward: Global Fixed-Priority Scheduling of Arbitrary-Deadline Sporadic Task SystemsFeb 28 2018The sporadic task model is often used to analyze recurrent execution of identical tasks in real-time systems. A sporadic task defines an infinite sequence of task instances, also called jobs, that arrive under the minimum inter-arrival time constraint. ... More

Singular Support of Minimizers of the Causal Variational Principle on the SphereAug 29 2018The support of minimizing measures of the causal variational principle on the sphere is analyzed. It is proven that in the case $\tau>\sqrt{3}$, the support of every minimizing measure is contained in a finite number of real analytic curves which intersect ... More

On some knot energies involving Menger curvatureSep 07 2012Nov 25 2012We investigate knot-theoretic properties of geometrically defined curvature energies such as integral Menger curvature. Elementary radii-functions, such as the circumradius of three points, generate a family of knot energies guaranteeing self-avoidance ... More

Effects of periodic forcing on a Paleoclimate delay modelAug 07 2018Jan 11 2019We present a study of a delay differential equation (DDE) model for the Mid-Pleistocene Transition (MPT). We investigate the behavior of the model when subjected to periodic forcing. The unforced model has a bistable region consisting of a stable equilibrium ... More

Towards a 229Th-based nuclear clockNov 09 2018Nov 12 2018An overview over the current status of the development of a nuclear clock based on the state of lowest known nuclear excitation energy in $^{229}$Th is presented. The text is especially written for the interested reader without any particular knowledge ... More

Radiative Type III Seesaw Model and its collider phenomenologyMay 04 2016Aug 02 2016We analyze the present bounds of a scotogenic model, the Radiative Type III Seesaw (RSIII), in which an additional scalar doublet and at least two fermion triplets of $SU(2)_L$ are added to the Standard Model (SM). In the RSIII the new physics (NP) sector ... More

What is an ideal a zero-class of?Feb 27 2016We characterise, in pointed regular categories, the ideals as the zero-classes of surjective relations. Moreover, we study a variation of the "Smith is Huq" condition: two surjective left split relations commute as soon as their zero-classes commute.

Algebraically coherent categoriesSep 15 2014Nov 06 2015We call a finitely complete category algebraically coherent when the change-of-base functors of its fibration of points are coherent, which means that they preserve finite limits and jointly strongly epimorphic pairs of arrows. We give examples of categories ... More

Some results on homology of Leibniz and Lie n-algebrasSep 11 2010From the viewpoint of semi-abelian homology, some recent results on homology of Leibniz n-algebras can be explained categorically. In parallel with these results, we develop an analogous theory for Lie n-algebras. We also consider the relative case: homology ... More

Revealing the properties of dark matter in the merging cluster MACSJ0025.4-1222Jun 13 2008Jul 23 2008We constrain the physical nature of dark matter using the newly identified massive merging galaxy cluster MACSJ0025.4-1222. As was previously shown by the example of the Bullet Cluster (1E0657-56), such systems are ideal laboratories for detecting isolated ... More