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Tunable localization in an s-electron Kondo system at room temperatureFeb 08 2019To achieve room-temperature superconductivity, a mechanism is needed that provides heavy quasiparticles at room temperature. In heavy fermion systems such localization is prototypically present only at liquid helium temperatures. In these $f$-electron ... More

Ab initio study on the effects of transition metal doping of Mg2NiH4Mar 21 2007Mg2NiH4 is a promising hydrogen storage material with fast (de)hydrogenation kinetics. Its hydrogen desorption enthalpy, however, is too large for practical applications. In this paper we study the effects of transition metal doping by first-principles ... More

A first-principles study of the electronic structure and stability of Be(BH4)2Dec 06 2007Alanates and boranates are studied intensively because of their potential use as hydrogen storage materials. In this paper we present a first-principles study of the electronic structure and the energetics of beryllium boranate, Be(BH4)2. From total energy ... More

Quantum Size Effects in the Atomistic Structure of Armchair-NanoribbonsNov 15 2011Quantum size effects in armchair graphene nano-ribbons (AGNR) with hydrogen termination are investigated via density functional theory (DFT) in Kohn-Sham formulation. "Selection rules" will be formulated, that allow to extract (approximately) the electronic ... More

A model for the formation energies of alanates and boranatesNov 27 2006We develop a simple model for the formation energies (FEs) of alkali and lkaline earth alanates and boranates, based upon ionic bonding between metal cations and (AlH4)- or (BH4)- anions. The FEs agree well with values obtained from first principles calculations ... More

Light-weight sodium alanate thin films grown by reactive sputteringOct 13 2009We report the preparation of sodium alanate, a promising hydrogen storage material, in a thin film form using co-sputtering in a reactive atmosphere of atomic hydrogen. We study the phase formation and distribution, and the hydrogen desorption, with a ... More

First-principles investigation of the structural, dynamical and dielectric properties of kesterite, stannite and PMCA phases of Cu2ZnSnS4Oct 18 2016Cu2ZnSnS4 (CZTS) is a promising material as an absorber in photovoltaic applications. The measured efficiency, however, is far from the theoretically predicted value for the known CZTS phases. To improve the understanding of this discrepancy we investigate ... More

Ab initio study of magnesium alanate, Mg(AlH4)2May 25 2005Magnesium alanate Mg(AlH4)2 has recently raised interest as a potential material for hydrogen storage. We apply ab initio calculations to characterize structural, electronic and energetic properties of Mg(AlH4)2. Density functional theory calculations ... More

First-principles study of the optical properties of MgxTi(1-x)H2Apr 02 2008The optical and electronic properties of Mg-Ti hydrides are studied using first-principles density functional theory. Dielectric functions are calculated for MgxTi(1-x)H2 with compositions x = 0.5, 0.75, and 0.875. The structure is that of fluorite TiH2 ... More

Electronic structure and optical properties of lightweight metal hydridesSep 08 2006We study the electronic structures and dielectric functions of the simple hydrides LiH, NaH, MgH2 and AlH3, and the complex hydrides Li3AlH6, Na3AlH6, LiAlH4, NaAlH4 and Mg(AlH4)2, using first principles density functional theory and GW calculations. ... More

$GW$100: a plane wave perspective for small moleculesOct 06 2016In a recent work, Van Setten and coworkers have presented a carefully converged $G_0W_0$ study of 100 closed shell molecules [J. Chem. Theory Comput. \textbf{11}, 5665 (2015)]. For two different codes they found excellent agreement to within few 10 meV ... More

Benchmark of GW approaches for the GW100 testsetSep 15 2016For the recent GW100 test set of molecular ionization energies, we present a comprehensive assessment of different GW methodologies: fully self-consistent GW (scGW), quasiparticle self-consistent GW (qsGW), partially self-consistent GW0 (scGW0), perturbative ... More

$GW$100: a plane wave perspective for small moleculesOct 06 2016Nov 24 2016In a recent work, van Setten and coworkers have presented a carefully converged $G_0W_0$ study of 100 closed shell molecules [J. Chem. Theory Comput. 11, 5665 (2015)]. For two different codes they found excellent agreement to within few 10 meV if identical ... More

First principles modelling of magnesium titanium hydridesOct 06 2009Mixing Mg with Ti leads to a hydride Mg(x)Ti(1-x)H2 with markedly improved (de)hydrogenation properties for x < 0.8, as compared to MgH2. Optically, thin films of Mg(x)Ti(1-x)H2 have a black appearance, which is remarkable for a hydride material. In this ... More

Computationally-driven, high throughput identification of CaTe and Li$_\textrm{3}$Sb as promising candidates for high mobility $p$-type transparent conducting materialsNov 13 2018High-performance $p$-type transparent conducting materials (TCMs) must exhibit a rare combination of properties including high mobility, transparency and $p$-type dopability. The development of high-mobility/conductivity $p$-type TCMs is necessary for ... More

First-principle study of paraelectric and ferroelectric CsH$_2$PO$_4$ including dispersion forces: stability and related vibrational, dielectric and elastic propertiesJan 26 2018Using density functional theory (DFT) and density functional perturbation theory (DFPT), we investigate the stability and response functions of CsH$_2$PO$_4$, a ferroelectric material at low temperature. This material cannot be described properly by the ... More

Reproducibility in $G_0W_0$ Calculations for SolidsMar 16 2019Ab initio many-body perturbation theory within the $GW$ approximation is a Green's function formalism widely used in the calculation of quasiparticle excitation energies of solids. In what has become an increasingly standard approach, Kohn-Sham eigenenergies, ... More

Domino MagnificationJan 03 2013Jan 28 2013The conditions are investigated under which a row of increasing dominoes is able to keep tumbling over. The analysis is restricted to the simplest case of frictionless dominoes that only can topple not slide. The model is scale invariant, i.e. dominoes ... More

The Domino EffectJan 07 2004The physics of a row of toppling dominoes is discussed. In particular the forces between the falling dominoes are analyzed and with this knowledge, the effect of friction has been incorporated. A set of limiting situations is discussed in detail, such ... More

On the masses of neutron starsMay 16 1995We analyze the currently available observations of X-ray binaries in a consistent way, to re-determine the masses of the neutron stars in these systems. In particular, our attention is focussed on a realistic and consistent assessment of observational ... More

The development of a mapping tool for the evaluation of building systems for future climate scenarios on European scaleJun 04 2015The paper presents a tool for the mapping of the performance of building systems on European scale for different (future) time periods. The tool is to use for users and be applicable for different building systems. Users should also be able to use a broad ... More

Crossover from Reptation to Rouse dynamics in the Cage ModelSep 12 2006The two-dimensional cage model for polymer motion is discussed with an emphasis on the effect of sideways motions, which cross the barriers imposed by the lattice. Using the Density Matrix Method as a solver of the Master Equation, the renewal time and ... More

Scaling in the Rubinstein-Duke Model for ReptationSep 17 2004We consider an arbitrarily charged polymer driven by a weak field through a gel according to the rules of the Rubinstein-Duke model. The probability distribution in the stationary state is related to that of the model in which only the head is charged. ... More

Crossover from Reptation to Rouse dynamics in the Extended Rubinstein-Duke ModelFeb 12 2008The competition between reptation and Rouse Dynamics is incorporated in the Rubinstein-Duke model for polymer motion by extending it with sideways motions, which cross barriers and create or annihilate hernias. Using the Density-Matrix Renormalization-Group ... More

Crossover from reptation to Rouse dynamics in a one-dimensional modelJun 16 2006A simple one-dimensional model is constructed for polymer motion. It exhibits the crossover from reptation to Rouse dynamics through gradually allowing hernia creation and annihilation. The model is treated by the density matrix technique which permits ... More

Exact Solution for a 1-dimensional model for ReptationFeb 21 2006We discuss the exact solution for the properties of the recently introduced ``necklace'' model for reptation. The solution gives the drift velocity, diffusion constant and renewal time for asymptotically long chains. Its properties are also related to ... More

Quantum suppression of shot noise in atom-size metallic contactsOct 21 1998Jul 16 1999The transmission of conductance modes in atom-size gold contacts is investigated by simultaneously measuring conductance and shot noise. The results give unambiguous evidence that the current in the smallest gold contacts is mostly carried by nearly fully ... More

Multiple imputation in data that grow over time: A comparison of three strategiesApr 08 2019Multiple imputation is a highly recommended technique to deal with missing data, but the application to longitudinal datasets can be done in multiple ways. When a new wave of longitudinal data arrives, we can treat the combined data of multiple waves ... More

Stochastic lattice models for the dynamics of linear polymersApr 14 2010Linear polymers are represented as chains of hopping reptons and their motion is described as a stochastic process on a lattice. This admittedly crude approximation still catches essential physics of polymer motion, i.e. the universal properties as function ... More

Decomposition Based Search - A theoretical and experimental evaluationJul 16 2004In this paper we present and evaluate a search strategy called Decomposition Based Search (DBS) which is based on two steps: subproblem generation and subproblem solution. The generation of subproblems is done through value ranking and domain splitting. ... More

Time Evolution of Decay Spectrum in K^0, K^0 bar -> pi^+ pi^- e^+ e^-Jun 29 2000Aug 04 2000We consider the decay K^0 (K^0 bar) -> pi^+ pi^- e^+ e^- of a neutral K meson prepared in a state of strangeness +1 (-1). The time evolution of the state produces remarkable time-dependent effects in the angular distribution of the pi^+ pi^- e^+ e^- system. ... More

Day-Night Effect for Solar Neutrinos: Coherent versus Incoherent Regeneration in the EarthFeb 23 1999Mar 25 1999Paper has been withdrawn by the authors.

Optimizing Tc in the (Mn,Cr,Ga)As and (Mn,Ga)(As,P) Ternary AlloysOct 17 2005We explore two possible ways to enhance the critical temperature $T_c$ in the dilute magnetic semiconductor Mn$_{0.08}$Ga$_{0.92}$As. Within the context of the double-exchange and RKKY pictures, the ternary alloys Mn$_{x}$Cr$_{0.08-x}$Ga$_{0.92}$As and ... More

Quantum Measurement Reliability versus ReversibilityJan 07 2009There is a constraining relation between the reliability of a quantum measurement and the extent to which the measurement process is, in principle, reversible. The greater the information that is gained, the less reversible the measurement dynamics become. ... More

The Role of Internal Photons on the Chemistry of the Circumstellar Envelopes of AGB StarsFeb 01 2019Recent high spatial resolution observations of gas and dust in the circumstellar envelopes (CSEs) of AGB stars indicate morphologies much more complex than the smooth density distributions generated by spherically symmetric, constant mass loss rates. ... More

Phase-space consistency of stellar dynamical models determined by separable augmented densitiesJan 31 2012Assuming the separable augmented density, it is always possible to construct a distribution function of a spherical population with any given density and anisotropy. We consider under what conditions the distribution constructed as such is in fact non-negative ... More

Measurement-based quantum computation and undecidable logicOct 06 2006Mar 27 2008We establish a connection between measurement-based quantum computation and the field of mathematical logic. We show that the computational power of an important class of quantum states called graph states, representing resources for measurement-based ... More

CP-Violation in the decay B^0, (B^0)bar -> pi^+ pi^- gammaAug 23 2002Aug 30 2002The decay (B^0)bar -> pi^+ pi^- gamma has a bremsstrahlung component determined by the amplitude for (B^0)bar -> pi^+ pi^-, as well as a direct component determined by the penguin interaction V_tb V^*_td c_7 O_7. Interference of these amplitudes produces ... More

Spectra of Modular and Small-World MatricesDec 02 2010We compute spectra of symmetric random matrices describing graphs with general modular structure and arbitrary inter- and intra-module degree distributions, subject only to the constraint of finite mean connectivities. We also evaluate spectra of a certain ... More

Single-photon Spectra in Quantum OptomechanicsMar 18 2014We consider how a single photon can probe the quantum nature of a moving mirror in the context of quantum optomechanics. In particular, we demonstrate how the single-photon spectrum reveals resonances that depend on how many phonons are created as well ... More

Reduced cost-based ranking for generating promising subproblemsJul 16 2004In this paper, we propose an effective search procedure that interleaves two steps: subproblem generation and subproblem solution. We mainly focus on the first part. It consists of a variable domain value ranking based on reduced costs. Exploiting the ... More

Spin injection, accumulation and spin precession in a mesoscopic non-magn etic metal islandNov 16 2004We experimentally study spin accumulation in an aluminium island with all dimensions smaller than the spin relaxation length, so that the spin imbalance throughout the island is uniform. Electrical injection and detection of the spin accumulation are ... More

Zero-dimensional spin accumulation and spin dynamics in a mesoscopic metal islandAug 20 2003We have measured electron spin accumulation at 4.2 K and at room temperature in an aluminium island with all dimensions (400nm x 400nm x 30nm) smaller than the spin relaxation length. For the first time, we obtain uniform spin accumulation in a four-terminal ... More

The Role of Internal Photons on the Chemistry of the Circumstellar Envelopes of AGB StarsFeb 01 2019Feb 28 2019Recent high spatial resolution observations of gas and dust in the circumstellar envelopes (CSEs) of AGB stars indicate morphologies much more complex than the smooth density distributions generated by spherically symmetric, constant mass loss rates. ... More

Mutually orthogonal latin squares with large holesOct 24 2014Two latin squares are orthogonal if, when they are superimposed, every ordered pair of symbols appears exactly once. This definition extends naturally to `incomplete' latin squares each having a hole on the same rows, columns, and symbols. If an incomplete ... More

Sedimentation of binary mixtures of like- and oppositely charged colloids: the primitive model or effective pair potentials?Dec 22 2005We study sedimentation equilibrium of low-salt suspensions of binary mixtures of charged colloids, both by Monte Carlo simulations of an effective colloids-only system and by Poisson-Boltzmann theory of a colloid-ion mixture. We show that the theoretically ... More

Canonical D = 1 supergravity framework for FLRW cosmologyMar 06 2015We construct an extension of standard flat FLRW cosmology with matter, possessing local D = 1, N = 1 proper-time supersymmetry. The fundamental equation for the resulting mini-superspace models of quantum universes is a Dirac-like analogue of the Friedmann ... More

The mechanical creep compliance of tissue cells is gamma distributedFeb 05 2010Jul 13 2011Investigations of natural variation among cells within a population are essential for understanding the stochastic nature of tissue cell deformation under applied load. In the existing literature, the population variation of single-cell creep compliance ... More

Stokes Vector of Photon in the Decays B^0 -> rho^0 gamma and B^0 -> K^* gammaMar 19 2004Apr 08 2004We consider a model for the decay Bbar^0 -> rho^0 gamma in which the short-distance amplitude determined by the Hamiltonian describing b -> d gamma is combined with a typical long-distance contribution Bbar^0 -> D^+ D^- -> rho^0 gamma. The latter possesses ... More

An electron spin injection driven, paramagnetic solid-state MASER deviceAug 04 2006In response to an external, microwave-frequency magnetic field, a paramagnetic medium will absorb energy from the field that drives the magnetization dynamics. Here we describe a new process by which an external spin injection source, when combined with ... More

Star Formation and Gas Accretion in Nearby GalaxiesAug 24 2016In order to quantify the relationship between gas accretion and star formation, we analyse a sample of 29 nearby galaxies from the WHISP survey which contains galaxies with and without evidence for recent gas accretion. We compare combined radial profiles ... More

Thermal conductance of interleaving finsJun 26 2019Interleaving fins can significantly increase the heat transfer by increasing the effective area per unit base area. The fins are separated uniformly by a gap, which is filled with a flow medium to control the heat flux. The heat flux between the plates ... More

The p-modular Descent Algebra of the Symmetric GroupJun 19 2007The descent algebra of the symmetric group, over a field of non-zero characteristic p, is studied. A homomorphism into the algebra of generalised p-modular characters of the symmetric group is defined. This is then used to determine the radical, and its ... More

Characterization of Two PMT Models for the IceCube Upgrade mDOMAug 22 2019The IceCube Upgrade will expand the IceCube Neutrino Observatory with nearly 800 new optical modules. A large fraction of these will be multi-PMT optical modules (mDOMs), featuring 24 PMTs pointing uniformly in all directions, providing an almost homogeneous ... More

Tumbling of a rigid rod in a shear flowJun 05 2014The tumbling of a rigid rod in a shear flow is analyzed in the high viscosity limit. Following Burgers, the Master Equation is derived for the probability distribution of the orientation of the rod. The equation contains one dimensionless number, the ... More

Performance Comparison of Short-Length Error-Correcting CodesSep 26 2016Nov 07 2016We compare the performance of short-length linear binary codes on the binary erasure channel and the binary-input Gaussian channel. We use a universal decoder that can decode any linear binary block code: Gaussian-elimination based Maximum-Likelihood ... More

Performance Comparison of Short-Length Error-Correcting CodesSep 26 2016Sep 30 2016We compare the performance of short-length linear binary codes on the binary erasure channel and the binary-input Gaussian channel. We use a universal decoder that can decode any linear binary block code: Gaussian-elimination based Maximum-Likelihood ... More

Performance Comparison of Short-Length Error-Correcting CodesSep 26 2016We compare the performance of short-length linear binary codes on the binary erasure channel and the binary-input Gaussian channel. We use a universal decoder that can decode any linear binary block code: Gaussian-elimination based Maximum-Likelihood ... More

A study of the HI and optical properties of Low Surface Brightness galaxies: spirals, dwarfs and irregularsFeb 18 2018We present a study of the HI and optical properties of nearby ($z$ $\le$ 0.1) Low Surface Brightness galaxies (LSBGs). We started with a literature sample of $\sim$900 LSBGs and divided them into three morphological classes: spirals, irregulars and dwarfs. ... More

On the mass distribution of neutron stars in HMXBsFeb 16 2005We present the results of a monitoring campaign of three eclipsing high-mass X-ray binaries (HMXBs: SMC X-1, LMC X-4 and Cen X-3). High-resolution VLT/UVES spectra are used to measure the radial velocities of these systems with high accuracy. We show ... More

Vacancy diffusion in the Cu(001) surface II: Random walk theoryOct 31 2001We develop a version of the vacancy mediated tracer diffusion model, which follows the properties of the physical system of In atoms diffusing within the top layer of Cu(001) terraces. This model differs from the classical tracer diffusion problem in ... More

Vacancy diffusion in the Cu(001) surface I: An STM studyOct 31 2001We have used the indium/copper surface alloy to study the dynamics of surface vacancies on the Cu(001) surface. Individual indium atoms that are embedded within the first layer of the crystal, are used as probes to detect the rapid diffusion of surface ... More

Optimal Tradeoff Between Exposed and Hidden Nodes in Large Wireless NetworksApr 07 2010Wireless networks equipped with the CSMA protocol are subject to collisions due to interference. For a given interference range we investigate the tradeoff between collisions (hidden nodes) and unused capacity (exposed nodes). We show that the sensing ... More

Bulk and Surface Nucleation Processes in Ag2S Conductance SwitchesAug 26 2011We studied metallic Ag formation inside and on the surface of Ag2S thin films, induced by the electric field created with a STM tip. Two clear regimes were observed: cluster formation on the surface at low bias voltages, and full conductance switching ... More

Applying an accurate spherical model to gamma-ray burst afterglow observationsFeb 04 2013We present results of model fits to afterglow data sets of GRB970508, GRB980703 and GRB070125, characterized by long and broadband coverage. The model assumes synchrotron radiation (including self-absorption) from a spherical adiabatic blast wave and ... More

Optimally Designed Digitally-Doped Mn:GaAsDec 15 2006We use the ab initio local-density approximation (LDA) to study of exchange interactions and Tc of Ga1−xMnxAs grown in digitally doped structures. We analyze the crystallographic dependence of exchange interactions predicted by the LDA in terms ... More

On the origin and extent of mechanical variation among cellsApr 04 2011Jun 21 2011Investigations of natural variation in cell mechanics within a cell population are essential to understand the stochastic nature of soft-network deformation. Striking commonalities have been found concerning the average values and distribution of rheological ... More

How Nonlinear Optical Effects degrade Hong-Ou-Mandel Like InterferenceOct 13 2015Two-photon interference effects, such as the Hong-Ou-Mandel (HOM) effect, can be used to characterize to what extent two photons are identical. Furthermore, these interference effects underly linear optics quantum computation. We show here how nonlinear ... More

Multiplicity distributions of quark and gluon jets in QCDAug 07 2000The solution of the equations for the generating functions of multiplicity distributions of quark and gluon jets in higher order 3NLO perturbative QCD is obtained. The non-perturbative effects are discussed as well. The results are compared to recent ... More

Symmetry-preserving finite-difference discretizations of arbitrary order on structured curvilinear staggered gridsJan 08 2019Symmetry-preserving (mimetic) discretizations exhibit the same properties as the corresponding continuous differential operator. For these discretizations, stability and (discrete) conservation of mass, momentum and energy are proven in the same way as ... More

Wishart Generator DistributionFeb 25 2015The Wishart distribution and its generalizations are among the most prominent probability distributions in multivariate statistical analysis, arising naturally in applied research and as a basis for theoretical models. In this paper, we generalize the ... More

A model-independent analysis of the variability of GRS 1915+105Jan 07 2000We analyzed 163 observations of the microquasar GRS 1915+105 made with the Rossi X-ray Timing Explorer (RXTE) in the period 1996-1997. For each observation, we produced light curves and color-color diagrams. We classified the observations in 12 separate ... More

Particle motion in electro-magnetic and gravitational pp-wavesAug 16 2002We discuss the motion of neutral and charged particles in a plane electro-magnetic wave and its accompanying gravitational field.

The role of tap duration for the steady state density of vibrated granular mediaMar 31 2009Jan 06 2010We revisit the problem of compaction of a column of granular matter exposed to discrete taps. We accurately control the vertical motion of the column, which allows us to vary the duration T and the amplitude A of single-cycle sinusoidal taps independently. ... More

Two-Photon Interference and Entanglement in Coupled CavitiesJun 04 2014Two-photon interference effects, such as the Hong-Ou-Mandel (HOM) effect, can be used to characterize to what extent two photons are identical. Identical photons are necessary for both linear optics quantum computing and single-photon quantum cryptography. ... More

Violation of Time Reversal Invariance in the Decays K_L -> pi^+ pi^- gamma and K_L -> pi^+ pi^- e^+ e^-Aug 20 1999The origin of the large CP-odd and T-odd asymmetry observed in the decay K_L -> pi^+ pi^- e^+ e^- is traced to the polarization properties of the photon in the decay K_L -> pi^+ pi^- gamma. The Stokes vector of the photon S = (S_1, S_2, S_3) is studied ... More

Noncommutative resolutions and rational singularitiesDec 01 2006Let k be an algebraically closed field of characteristic zero. We show that the centre of a homologically homogeneous, finitely generated k-algebra has rational singularities. In particular if a finitely generated normal commutative k-algebra has a noncommutative ... More

Noncommutative curves and noncommutative surfacesOct 16 1999Jul 26 2000In this survey article we describe some geometric results in the theory of noncommutative rings and, more generally, in the theory of abelian categories. Roughly speaking and by analogy with the commutative situation, the category of graded modules modulo ... More

Determination of the mass of the neutron star in SMC X-1, LMC X-4 and Cen X-3 with VLT/UVESJul 18 2007We present the results of a spectroscopic monitoring campaign of the OB-star companions to the eclipsing X-ray pulsars SMC X-1, LMC X-4 and Cen X-3. High-resolution optical spectra obtained with UVES on the ESO Very Large Telescope are used to determine ... More

Single-photon time-dependent spectra in coupled cavity arraysMay 14 2013We show how the input-output formalism for cascaded quantum systems combined with the quantum trajectory approach yields a compact and physically intuitive description of single photons propagating through a coupled cavity array. As a new application ... More

Extension of Fixed-Node Monte Carlo for Lattice FermionsOct 09 1995In a previous paper, we have described a method to perform Fixed-Node Quantum Monte Carlo calculations for lattice fermions. In this paper, we present an extension of this method, by which it is possible to find information on the properties of the exact ... More

Gamma-Ray Burst afterglow scaling coefficients for general density profileOct 13 2008Dec 18 2008Gamma-ray burst (GRB) afterglows are well described by synchrotron emission originating from the interaction between a relativistic blast wave and the external medium surrounding the GRB progenitor. We introduce a code to reconstruct spectra and light ... More

Weak dispersive forces between glass-gold macroscopic surfaces in alcoholsApr 03 2009Apr 06 2009In this work we concentrate on an experimental validation of the Lifshitz theory for van der Waals and Casimir forces in gold-alcohol-glass systems. From this theory weak dispersive forces are predicted when the dielectric properties of the intervening ... More

The formation of the double neutron star pulsar J0737--3039Dec 05 2003We find that the orbital period (2.4 hours), eccentricity (0.09), dipole magnetic field strength (6.9 x 10^9 Gauss) and spin period (22 ms) of the new highly relativistic double neutron star system PSR J0737-3039 can all be consistently explained if this ... More

Magnetic fields and shock waves in cluster outskirtsFeb 09 2011Both, X-ray and radio observations, are beginning to probe regions in galaxy clusters close to the virial radius. These are particularly interesting regions as they are (i) crucial for the thermal evolution of the intra-cluster medium and (ii) they host ... More

Simulating the Toothbrush: Evidence for a triple merger of galaxy clustersJun 26 2012Jul 18 2012The newly discovered galaxy cluster 1RXS J0603.3+4214 hosts a 1.9 Mpc long, bright radio relic with a peculiar linear morphology. Using hydrodynamical +N-body AMR simulations of the merger between three initially hydrostatic clusters in an idealised setup, ... More

Sharpness versus robustness of the percolation transition in 2D contact processesJun 05 2013Sep 16 2014We study versions of the contact process with three states, and with infections occurring at a rate depending on the overall infection density. Motivated by a model described in [17] for vegetation patterns in arid landscapes, we focus on percolation ... More

Dynamics of a double-stranded DNA segment in a shear flowMar 16 2016We study the dynamics of a double-stranded DNA (dsDNA) segment, as a semiflexible polymer, in a shear flow, the strength of which is customarily expressed in terms of the dimensionless Weissenberg number Wi. Polymer chains in shear flows are well-known ... More

Efficient simulation of semiflexible polymersNov 13 2014Sep 10 2015Using a recently developed bead-spring model for semiflexible polymers that takes into account their natural extensibility, we report an efficient algorithm to simulate the dynamics for polymers like double-stranded DNA (dsDNA) in the absence of hydrodynamic ... More

Anharmonic double-phonon excitations in the interacting boson modelJul 13 2000Double-$\gamma$ vibrations in deformed nuclei are analyzed in the context of the interacting boson model. A simple extension of the original version of the model towards higher-order interactions is required to explain the observed anharmonicities of ... More

Dephasing of entangled electron-hole pairs in a degenerate electron gasJul 09 2003A tunnel barrier in a degenerate electron gas was recently discovered as a source of entangled electron-hole pairs. Here, we investigate the loss of entanglement by dephasing. We calculate both the maximal violation E_max of the Bell inequality and the ... More

Diffuse steep-spectrum sources from the 74 MHz VLSS surveyJan 20 2011Galaxy clusters grow by a sequence of mergers with other clusters and galaxy groups. During these mergers, shocks and/or turbulence are created within the intracluster medium (ICM). In this process, particles could be accelerated to highly relativistic ... More

Asymptotics of the maximum of Brownian motion under Erlangian samplingMar 15 2013Consider the all-time maximum of a Brownian motion with negative drift. Assume that this process is sampled at certain points in time, where the time between two consecutive points is rendered by an Erlang distribution with mean $1/\omega$. The family ... More

Magnetophoresis in the Rubinstein-Duke modelJun 20 2003We consider the magnetophoresis problem within the Rubinstein-Duke model, i.e. a reptating polymer pulled by a constant field applied to a single repton at the edge of a chain. Extensive density matrix renormalization calculations are presented of the ... More

Force correlations in the q-model for general q-distributionsFeb 07 2002We study force correlations in the q-model for granular media at infinite depth, for general q-distributions. We show that there are no 2-point force correlations as long as q-values at different sites are uncorrelated. However, higher order correlations ... More

Crossover behavior for long reptating polymersOct 12 2000We analyze the Rubinstein-Duke model for polymer reptation by means of density matrix renormalization techniques. We find a crossover behavior for a series of quantities as function of the polymer length. The crossover length may become very large if ... More

Ultrafast Deflection of Spatial Solitons in AlGaAs Slab WaveguidesAug 31 2005We demonstrate ultrafast all-optical deflection of spatial solitons in an AlGaAs slab waveguide using 190 fs, 1550 nm pulses which are used to generate and deflect the spatial soliton. The steering beam is focused onto the top of the waveguide near the ... More

Semiflexible Polymer Dynamics with a Bead-Spring ModelOct 01 2014We study the dynamical properties of semiflexible polymers with a recently introduced bead-spring model. We focus on double-stranded DNA. The two parameters of the model, $T^*$ and $\nu$, are chosen to match its experimental force-extension curve. The ... More

On Lerch's transcendent and the Gaussian random walkMar 30 2007Let $X_1,X_2,...$ be independent variables, each having a normal distribution with negative mean $-\beta<0$ and variance 1. We consider the partial sums $S_n=X_1+...+X_n$, with $S_0=0$, and refer to the process $\{S_n:n\geq0\}$ as the Gaussian random ... More

The Chandra LETG and XMM-Newton Spectra of HR 1099Jan 31 2002The X-ray luminous RS CVn binary system HR 1099 has been observed on several occasions in the early phases of \textit{Chandra} and \textit{XMM-Newton}. A very hot (up to 40 MK) dominant coronal plasma has been identified from the high-resolution spectroscopic ... More