Results for "M. Mueller"

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Numerical hydrodynamics in special relativityJun 21 1999This review is concerned with a discussion of numerical methods for the solution of the equations of special relativistic hydrodynamics (SRHD). Particular emphasis is put on a comprehensive review of the application of high-resolution shock-capturing ... More
Nucleosynthesis and the variation of fundamental couplingsMay 19 2004We determine the influence of a variation of the fundamental ``constants'' on the predicted helium abundance in Big Bang Nucleosynthesis. The analytic estimate is performed in two parts: the first step determines the dependence of the helium abundance ... More
Spectral Statistics of the Two-Body Random Ensemble RevisitedJun 08 2000Using longer spectra we re-analyze spectral properties of the two-body random ensemble studied thirty years ago. At the center of the spectra the old results are largely confirmed, and we show that the non-ergodicity is essentially due to the variance ... More
Trapped Rydberg Ions: From Spin Chains to Fast Quantum GatesSep 18 2007Apr 19 2008We study the dynamics of Rydberg ions trapped in a linear Paul trap, and discuss the properties of ionic Rydberg states in the presence of the static and time-dependent electric fields constituting the trap. The interactions in a system of many ions are ... More
Statistical Physics of RNA-foldingJun 13 2002Dec 23 2002We discuss the physics of RNA as described by its secondary structure. We examine the static properties of a homogeneous RNA-model that includes pairing and base stacking energies as well as entropic costs for internal loops. For large enough costs the ... More
A Simple Model for Simple Aging in Glassy Yttrium-HydridesNov 15 2005A simple explanation for the logarithmic aging of the photoconductivity in yttriumhydride is proposed. We show that the scaling (``simple'' aging) of the relaxation response with the illumination time t_w is consistent with the superposition of independently ... More
A Doubly non-Linear Superconducting QubitApr 03 2019We describe a superconducting circuit consisting of a Josephson junction in parallel with a quantum phase slip wire, which implements a Hamiltonian that is periodic in both charge and flux. This Hamiltonian is exactly diagonalisable in a double-Bloch ... More
Non-equilibrium Fractional Hall Response After a Topological QuenchAug 15 2016Nov 09 2016We theoretically study the Hall response of a lattice system following a quench where the topology of a filled band is suddenly changed. In the limit where the physics is dominated by a single Dirac cone, we find that the change in the Hall conductivity ... More
Interplay between the orbital quantization and Pauli effect in a charge-density-wave organic conductorDec 11 2003The interlayer magnetoresistance of the low-dimensional organic metal \alpha-(BEDT-TTF)2KHg(SCN)4 under pressure shows features which are likely associated with theoretically predicted field-induced charge-density-wave (FICDW) transitions. At ambient ... More
Gauge-Invariant Initial Conditions and Early Time Perturbations in Quintessence UniversesApr 11 2003Sep 19 2003We present a systematic treatment of the initial conditions and evolution of cosmological perturbations in a universe containing photons, baryons, neutrinos, cold dark matter, and a scalar quintessence field. By formulating the evolution in terms of a ... More
Permutation groups of prime degree, a quick proof of Burnside's theoremOct 14 2003A transitive permutation group of prime degree is doubly transitive or solvable. We give a direct proof of this theorem by Burnside which uses neither S-ring type arguments, nor representation theory.
Measurement of the single top quark and antiquark production cross sections in the $t$ channel and their ratio at 13 TeVJan 16 2019The electroweak production in the $t$ channel is the most dominant production mode of single top quarks at the LHC. The ratio of the cross sections of the top quark and antiquark production provides an insight into the inner structure of the proton and ... More
Simulations of Relativistic Jets with GENESISOct 26 1999The multidimensional relativistic hydrodynamical code GENESIS has been used to obtain first results of {\it 3D} simulations of relativistic jets. We have studied the influence of a slight perturbation of the injection velocity field on the morphodynamics ... More
MATSuMoTo: The MATLAB Surrogate Model Toolbox For Computationally Expensive Black-Box Global Optimization ProblemsApr 16 2014MATSuMoTo is the MATLAB Surrogate Model Toolbox for computationally expensive, black-box, global optimization problems that may have continuous, mixed-integer, or pure integer variables. Due to the black-box nature of the objective function, derivatives ... More
Asymptotics of automorphic spectra and the trace formulaSep 22 2015This paper is a survey article on the limiting behavior of the discrete spectrum of the right regular representation in $L^2(\Gamma\bs G)$ for a lattice $\Gamma$ in a reductive group $G$ over a number field. We discuss various aspects of the Weyl law, ... More
Calculation of the Phase Behavior of LipidsFeb 24 1998The self-assembly of monoacyl lipids in solution is studied employing a model in which the lipid's hydrocarbon tail is described within the Rotational Isomeric State framework and is attached to a simple hydrophilic head. Mean-field theory is employed, ... More
Early Quintessence in Light of WMAPFeb 25 2003Dec 01 2006We examine the cosmic microwave background (CMB) anisotropy for signatures of early quintessence dark energy -- a non-negligible quintessence energy density during the recombination and structure formation eras. Only very recently does the quintessence ... More
Simple Calculation of Quantum Spin Tunneling EffectsApr 22 1997The level splitting formulae much discussed in the study of spin tunneling in macroscopic ferromagnetic particles and previously derived only by complicated pseudoparticle methods for the ground state, are derived from those of eigenvalues of periodic ... More
Remanent magnetization: signature of Many-Body Localization in quantum antiferromagnetsAug 22 2016Sep 12 2016We study the remanent magnetization in antiferromagnetic, many-body localized quantum spin chains, initialized in a fully magnetized state. Its long time limit is an order parameter for the localization transition, which is readily accessible by standard ... More
Successive Umbrella SamplingJun 26 2003We propose an extension of umbrella sampling in which the pertinent range of states is subdivided in windows that are sampled consecutively and linked together. Extrapolating results from one window we estimate a weight function for the neighboring window. ... More
Deviations from the mean field predictions for the phase behaviour of random copolymers meltsDec 19 2001We investigate the phase behaviour of random copolymers melts via large scale Monte Carlo simulations. We observe macrophase separation into A and B--rich phases as predicted by mean field theory only for systems with a very large correlation lambda of ... More
Investigating a Possible Spectral Signature of the Wind-ISM Interaction Region of Alpha TauSep 04 2002Ultraviolet spectra from the GHRS instrument on board the Hubble Space Telescope reveal the presence of a mysterious absorption feature in the Mg II h & k lines of the nearby (d=20.0 pc) K5 III star Alpha Tau. The narrow absorption looks like an interstellar ... More
Cosmological bounds on the equation of state of dark matterOct 26 2004Feb 09 2005In this exploratory study, we investigate the bounds on the equation of state of dark matter. Modeling dark matter as a fluid component, we take into account both positive and negative fixed equations of state. Using CMB, supernovae Ia and large scale ... More
Cosmological Markov Chain Monte Carlo simulation with CmbeasyJun 08 2004We introduce a Markov Chain Monte Carlo simulation and data analysis package for the cosmological computation package Cmbeasy. We have taken special care in implementing an adaptive step algorithm for the Markov Chain Monte Carlo in order to improve convergence. ... More
Early Quintessence and the CMBOct 15 2003We examine the cosmic microwave background (CMB) anisotropy for signatures of early quintessence dark energy -- a non-negligible quintessence energy density during the recombination and structure formation eras. In contrast to a $\Lambda$CDM cosmology, ... More
Optimizing the search for resources by sharing information: Mongolian gazelles as a case studyJan 23 2013Jun 20 2013We investigate the relationship between communication and search efficiency in a biological context by proposing a model of Brownian searchers with long-range pairwise interaction. After a general study of the properties of the model, we show an application ... More
Localized inter-valley defect excitons as single-photon emitters in WSe$_2$Apr 05 2019Single-photon emitters play a key role in present and emerging quantum technologies. Several recent measurements have established monolayer WSe$_2$ as a promising candidate for a reliable single photon source. The origin and underlying microscopic processes ... More
Static and dynamic structure factors in the Haldane phase of the bilinear-biquadratic spin-1Mar 12 1998The excitation spectra of the T=0 dynamic structure factors for the spin, dimer, and trimer fluctuation operators as well as for the newly defined center fluctuation operator in the one-dimensional S=1 Heisenberg model wi th isotropic bilinear $(J\cos\theta)$ ... More
Performance studies of the two-step multiboson algorithm in compact lattice QEDNov 17 2001The performance of the two-step multiboson (TSMB) algorithm is investigated in comparison with the hybrid Monte Carlo (HMC) method for compact lattice QED with standard Wilson fermions both in the Coulomb and confinement phases. The restriction to QED ... More
Orbital quantization in the high magnetic field state of a charge-density-wave systemMay 06 2003A superposition of the Pauli and orbital coupling of a high magnetic field to charge carriers in a charge-density-wave (CDW) system is proposed to give rise to transitions between subphases with quantized values of the CDW wavevector. By contrast to the ... More
Monte Carlo simulations of interfaces in polymer blendsMar 10 1998We review recent simulation studies of interfaces between immiscible homopolymer phases. Special emphasis is given to the presentation of efficient simulation techniques and powerful methods of data analysis, such as the analysis of capillary wave spectra. ... More
Wetting and Capillary Condensation in Symmetric Polymer Blends: A comparison between Monte Carlo Simulations and Self-Consistent Field CalculationsMay 26 1998We present a quantitative comparison between extensive Monte Carlo simulations and self-consistent field calculations on the phase diagram and wetting behavior of a symmetric, binary (AB) polymer blend confined into a film. The flat walls attract one ... More
Parameter Estimation and Confidence Regions in the Method of Light Curve Simulations for the Analysis of Power Density SpectraMay 21 2009The Method of Light Curve Simulations is a tool that has been applied to X-ray monitoring observations of Active Galactic Nuclei (AGN) for the characterization of the Power Density Spectrum (PDS) of temporal variability and measurement of associated break ... More
Interface localisation-delocalisation transition in a symmetric polymer blend: a finite-size scaling Monte Carlo studyOct 20 2000Using extensive Monte Carlo simulations we study the phase diagram of a symmetric binary (AB) polymer blend confined into a thin film as a function of the film thickness D. The monomer-wall interactions are short ranged and antisymmetric, i.e, the left ... More
Non-equilibrium quantum-heat statistics under stochastic projective measurementsMay 02 2018In this paper we aim at characterizing the effect of stochastic fluctuations on the distribution of the energy exchanged by a quantum system with an external environment under sequences of quantum measurements performed at random times. Both quenched ... More
CMOS-compatible graphene photodetector covering all optical communication bandsFeb 15 2013Sep 16 2013Optical interconnects are becoming attractive alternatives to electrical wiring in intra- and inter-chip communication links. Particularly, the integration with silicon complementary metal-oxide-semiconductor (CMOS) technology has received considerable ... More
Device physics of van der Waals heterojunction solar cellsMar 07 2019Heterostructures based on atomically thin semiconductors are considered a promising emerging technology for the realization of ultrathin and ultralight photovoltaic solar cells on flexible substrates. Much progress has been made in recent years on a technological ... More
Optical imaging of strain in two-dimensional crystalsMar 07 2019Strain engineering is widely used in material science to tune the (opto-)electronic properties of materials and enhance the performance of devices. Two-dimensional atomic crystals are a versatile playground to study the influence of strain, as they can ... More
Vacuum Polarization and the Electric Charge of the PositronSep 05 1992Nov 10 1992We show that higher-order vacuum polarization would contribute a measureable net charge to atoms, if the charges of electrons and positrons do not balance precisely. We obtain the limit $|Q_e+Q_{\bar e}| < 10^{-18} e$ for the sum of the charges of electron ... More
Fueling AGN II: Spatially Resolved Molecular Inflows and OutflowsJul 09 2014We analyse the 2-dimensional distribution and kinematics of the stars as well as molecular and ionised gas in the central few hundred parsecs of 5 active and 5 matched inactive galaxies. The equivalent widths of the Br-gamma line indicate there is no ... More
Cluster expansion for dimerized spin systemsJul 18 2001We have studied dimerized spin systems by realizing the cluster expansion to high order. We have extended our previous dimer expansion for one-dimensional systems to cover weakly interacting chains for a quantitative description of three dimensional materials ... More
Definition of Magnetic Monopole Numbers for SU(N) Lattice Gauge-Higgs ModelsJan 23 1999A geometric definition for a magnetic charge of Abelian monopoles in SU(N) lattice gauge theories with Higgs fields is presented. The corresponding local monopole number defined for almost all field configurations does not require gauge fixing and is ... More
Dynamical Structure Factors for the Heisenberg Chain with Alternating ExchangeNov 15 2002Nov 20 2002We discuss the transition strength between the disordered ground state and the basic low-lying triplet excitation for the Heisenberg chain with alternating exchange based on series expansions in the interdimer interaction up to tenth order. We demonstrate ... More
Constraints on the Low-Energy Cutoff in the Electron Distribution of the PKS 0637-752 JetNov 18 2008We re-analyze the Chandra ACIS spectrum of the kpc-scale jet in PKS 0637-752 to investigate the possible low energy cutoff in the relativistic electron spectrum producing the non-thermal radiation in the scenario of inverse Compton emission off the cosmic ... More
On the dynamics of coupled S=1/2 antiferromagnetic zig-zag chainsMar 02 2000Aug 23 2000We investigate the elementary excitations of quasi one-dimensional S=1/2 systems built up from zig-zag chains with general isotropic exchange constants, using exact (Lanczos) diagonalization for 24 spins and series expansions starting from the decoupled ... More
The glass transition and the Coulomb gap in electron glassesJun 14 2004We establish the connection between the presence of a glass phase and the appearance of a Coulomb gap in disordered materials with strongly interacting electrons. Treating multiparticle correlations in a systematic way, we show that in the case of strong ... More
Densities and filling factors of the DIG in the Solar neighbourhoodJul 23 2008For the first time we have combined dispersion measures and emission measures towards 38 pulsars at KNOWN distances from which we derived the mean electron density in clouds, N_c, and their volume filling factor, F_v, averaged along the line of sight. ... More
Magnetic catalysis and inverse magnetic catalysis in QCDFeb 27 2015May 13 2015We investigate the effects of strong magnetic fields on the QCD phase structure at vanishing density by solving the gluon and quark gap equations, and by studying the dynamics of the quark scattering with the four-fermi coupling. The chiral crossover ... More
The formation of disk galaxies in a cosmological context: Populations, metallicities and metallicity gradientsDec 05 1993We present first results concerning the metallicities and stellar populations of galaxies formed in a cosmologically motivated simulation. The calculations include dark matter, gas dynamics, radiation processes, star formation, supernovae feedback, and ... More
The analytic torsion and its asymptotic behaviour for sequences of hyperbolic manifolds of finite volumeJul 18 2013In this paper we study the regularized analytic torsion of finite volume hyperbolic manifolds. We consider sequences of coverings $X_i$ of a fixed hyperbolic orbifold $X_0$. Our main result is that for certain sequences of coverings and strongly acyclic ... More
World-line formulation of chiral kinetic theory in topological background gauge fieldsDec 11 2017In heavy-ion collisions, an interesting question of phenomenological relevance is how the chiral imbalance generated at early times persists through a fluctuating background of sphalerons in addition to other "non-anomalous" interactions with the QGP. ... More
Crowdbreaks: Tracking Health Trends using Public Social Media Data and CrowdsourcingMay 14 2018In the past decade, tracking health trends using social media data has shown great promise, due to a powerful combination of massive adoption of social media around the world, and increasingly potent hardware and software that enables us to work with ... More
Analyze This! A Cosmological Constraint Package for CMBEASYNov 13 2003Sep 15 2004We introduce a Markov Chain Monte Carlo simulation and data analysis package that extends the CMBEASY software. We have taken special care in implementing an adaptive step algorithm for the Markov Chain Monte Carlo in order to improve convergence. Data ... More
Concentration and energy fluctuations in a critical polymer mixtureNov 02 1994A semi-grand-canonical Monte Carlo algorithm is employed in conjunction with the bond fluctuation model to investigate the critical properties of an asymmetric binary (AB) polymer mixture. By applying the equal peak-weight criterion to the concentration ... More
Discovery of a New Quasar: SDSS J022155.26-064916.6Sep 10 2017We report the discovery of a new quasar: SDSS J022155.26-064916.6. This object was discovered while reducing spectra of a sample of stars being considered as spectrophotometric standards for the Dark Energy Survey. The flux and wavelength calibrated spectrum ... More
A Stochastic Heisenberg InequalityJun 17 2003An analogue of the Fourier transform will be introduced for all square integrable continuous martingale processes whose quadratic variation is deterministic. Using this transform we will formulate and prove a stochastic Heisenberg inequality.
Lasso tuning through the flexible-weighted bootstrapMar 10 2019Regularized regression approaches such as the Lasso have been widely adopted for constructing sparse linear models in high-dimensional datasets. A complexity in fitting these models is the tuning of the parameters which control the level of introduced ... More
Infinite excursions of rotor walks on regular treesNov 18 2015Jul 04 2017A rotor configuration on a graph contains in every vertex an infinite ordered sequence of rotors, each is pointing to a neighbor of the vertex. After sampling a configuration according to some probability measure, a rotor walk is a deterministic process: ... More
Scattering at low energies on manifolds with cylindrical ends and stable systolesJul 20 2009Nov 14 2017Scattering theory for p-forms on manifolds with cylindrical ends has a direct interpretation in terms of cohomology. Using the Hodge isomorphism,the scattering matrix at low energy may be regarded as operator on the cohomology of the boundary. Its value ... More
James' Conjecture for Hecke algebras of exceptional type, IDec 11 2007Oct 30 2008In this paper, and a second part to follow, we complete the programme (initiated more than 15 years ago) of determining the decomposition numbers and verifying James' Conjecture for Iwahori--Hecke algebras of exceptional type. The new ingredients which ... More
Could the physical world be emergent instead of fundamental, and why should we ask? (short version)Dec 05 2017In physics, there is the prevailing intuition that we are part of a unique external world, and that the goal of physics is to understand and describe this world. This assumption of the fundamentality of objective reality is often seen as a major prerequisite ... More
A remark on the denoising of greyscale images using energy densities with varying growth ratesMar 28 2018We prove the solvability in Sobolev spaces for a class of variational problems related to the TV-model proposed by Rudin, Osher and Fatemi in [1] for the denoising of greyscale images. In contrast to their approach we discuss energy densities with variable ... More
The Memory Effect in Electron GlassesMay 02 2005Sep 29 2005We present a theory for the memory effect in electron glasses. In fast gate voltage sweeps it is manifested as a dip in the conductivity around the equilibration gate voltage. We show that this feature, also known as anomalous field effect, arises from ... More
Localization of disordered bosons and magnets in random fieldsJun 11 2013Jul 19 2013We study localization properties of disordered bosons and spins in random fields at zero temperature. We focus on two representatives of different symmetry classes, hard-core bosons (XY magnets) and Ising magnets in random transverse fields, and contrast ... More
Mean field theory of superglassesNov 25 2011Mar 20 2012We study the interplay of superfluidity and glassy ordering of hard core bosons with random, frustrating interactions. This is motivated by bosonic systems such as amorphous supersolid, disordered superconductors with preformed pairs, and helium in porous ... More
The critical Branching Markov Chain is transientOct 26 2005We investigate recurrence and transience of Branching Markov Chains (BMC) in discrete time. Branching Markov Chains are clouds of particles which move (according to an irreducible underlying Markov Chain) and produce offspring independently. The offspring ... More
Super-Brownian motion with extra birth at one pointNov 27 2002Dec 09 2002A super-Brownian motion in two and three dimensions is constructed where "particles" give birth at a higher rate, if they approach the origin. Via a log-Laplace approach, the construction is based on Albeverio et al. (1995) who calculated the fundamental ... More
Exact Parent Hamiltonian for the Quantum Hall States in a Optical LatticeMay 18 2010Mar 31 2011We study lattice models of charged particles in uniform magnetic fields. We show how longer range hopping can be engineered to produce a massively degenerate manifold of single-particle ground states with wavefunctions identical to those making up the ... More
Exponential growth of torsion in the cohomology of arithmetic hyperbolic manifoldsMar 14 2019For d=2n+1 a positive odd integer, we consider sequences of arithmetic subgroups of SO_0(d,1) and Spin(d,1) yielding corresponding hyperbolic manifolds of finite volume and show that, under appropriate and natural assumptions, the torsion of the associated ... More
Extrapolation of Vector valued Rearrangement Operators IIFeb 09 2009We determine the extrapolation law for rearrangement operators of the Haar system on vector valued Hardy spaces.
Submission of content to a digital object repository using a configurable workflow systemJun 03 2007The prototype of a workflow system for the submission of content to a digital object repository is here presented. It is based entirely on open-source standard components and features a service-oriented architecture. The front-end consists of Java Business ... More
Stable Crank-Nicolson Discretisation for Incompressible Miscible Displacement Problems of Low RegularityOct 08 2009In this article we study the numerical approximation of incompressible miscible displacement problems with a linearised Crank-Nicolson time discretisation, combined with a mixed finite element and discontinuous Galerkin method. At the heart of the analysis ... More
On residuals of finite groupsAug 14 2017A theorem of Dolfi, Herzog, Kaplan, and Lev \cite[Thm.~C]{DHKL} asserts that in a finite group with trivial Fitting subgroup, the size of the soluble residual of the group is bounded from below by a certain power of the group order, and that the inequality ... More
A Liouville theorem for stationary incompressible fluids of von Mises typeMay 22 2018We consider entire solutions $u$ of the equations describing the stationary flow of a generalized Newtonian fluid in 2D concentrating on the question, if a Liouville-type result holds in the sense that the boundedness of $u$ implies its constancy. A positive ... More
Approximation of the interface condition for stochastic Stefan-type problemsMar 28 2018Oct 26 2018We consider approximations of the Stefan-type condition by imbalances of volume closely around the inner interface and study convergence of the solutions of the corresponding semilinear stochastic moving boundary problems. After a coordinate transformation, ... More
Can the Stochastic Wave Equation with Strong Drift Hit Zero?Feb 26 2018Feb 13 2019We study the stochastic wave equation with multiplicative noise and singular drift: \[ \partial_tu(t,x)=\Delta u(t,x)+u^{-\alpha}(t,x)+g(u(t,x))\dot{W}(t,x) \] where $x$ lies in the circle $\mathbf{R}/J\mathbf{Z}$ and $u(0,x)>0$. We show that (i) If $0<\alpha<1$ ... More
Fractional Sums and Euler-like IdentitiesFeb 05 2005Jun 27 2007We introduce a natural definition for sums of the form \[ \sum_{\nu=1}^x f(\nu) \] when the number of terms x is a rather arbitrary real or even complex number. The resulting theory includes the known interpolation of the factorial by the gamma function ... More
Constructing phase space distributions with internal symmetriesJan 29 2019Feb 22 2019We discuss an ab initio world-line approach to constructing phase space distributions in systems with internal symmetries. Starting from the Schwinger-Keldysh real time path integral in quantum field theory, we derive the most general extension of the ... More
On critical normal sections for two-dimensional immersions in R^{n+2}Sep 06 2007We study orthonormal normal sections of two-dimensional immersions in $\mathbb R^{n+2},$ $n\ge 2$, at which these sections are critical for a functional of total torsion. In particular, we establish upper bounds for the torsion coefficients in the case ... More
How to Add a Noninteger Number of Terms: From Axioms to New IdentitiesJan 26 2010Mar 02 2011Starting from a small number of well-motivated axioms, we derive a unique definition of sums with a noninteger number of addends. These "fractional sums" have properties that generalize well-known classical sum identities in a natural way. We illustrate ... More
Analytic torsion and Reidemeister torsion of hyperbolic manifolds with cuspsMar 14 2019On an odd-dimensional oriented hyperbolic manifold of finite volume with strongly acyclic coefficient systems, we derive a formula relating analytic torsion with the Reidemeister torsion of the Borel-Serre compactification of the manifold. In a companion ... More
Refining the Central Limit Theorem Approximation via Extreme Value TheoryFeb 02 2018We suggest approximating the distribution of the sum of independent and identically distributed random variables with a Pareto-like tail by combining extreme value approximations for the largest summands with a normal approximation for the sum of the ... More
Singular spherical maximal operators on a class of two step nilpotent Lie groupsJul 03 2003Let $H^n\cong \Bbb R^{2n}\ltimes \Bbb R$ be the Heisenberg group and let $\mu_t$ be the normalized surface measure for the sphere of radius $t$ in $\Bbb R^{2n}$. Consider the maximal function defined by $Mf=\sup_{t>0} |f*\mu_t|$. We prove for $n\ge 2$ ... More
Solutions of semilinear wave equation via stochastic cascadesNov 29 2009We introduce a probabilistic representation for solutions of quasilinear wave equation with analytic nonlinearities. We use stochastic cascades to prove existence and uniqueness of the solution.
Compton Scattering from \nuc{6}{Li} at 86 MeVMay 20 2014Aug 07 2014Cross sections for \nuc{6}{Li}($\gamma$,$\gamma$)\nuc{6}{Li} have been measured at the High Intensity Gamma-Ray Source (\HIGS) and the sensitivity of these cross sections to the nucleon isoscalar polarizabilities was studied. Data were collected using ... More
A New Mechanism of Model Membrane Fusion Determined from Monte Carlo SimulationDec 12 2002May 05 2003We have carried out extensive Monte Carlo simulations of the fusion of tense apposed bilayers formed by amphiphilic molecules within the framework of a coarse grained lattice model. The fusion pathway differs from the usual stalk mechanism. Stalks do ... More
Multifractality and quantum-to-classical crossover in the Coulomb anomaly at the Mott-Anderson metal-insulator transitionMay 01 2013Sep 24 2013We study the interaction driven localization transition, which a recent experiment in Ga_{1-x}Mn_xAs As has shown to come along with multifractal behavior of the local density of states (LDoS) and the intriguing persistence of critical correlations close ... More
Storage-ring measurement of the hyperfine induced 47Ti18+(2s 2p 3P0 -> 2s2 1S0) transition rateDec 15 2006The hyperfine induced 2s 2p 3P0 > 2s2 1S0 transition rate AHFI in berylliumlike 47Ti18+ was measured. Resonant electron-ion recombination in a heavy-ion storage ring was employed to monitor the time dependent population of the 3P0 state. The experimental ... More
Photorecombination of berylliumlike Ti18+: Hyperfine quenching of dielectronic resonancesSep 08 2006The photorecombination spectrum of 48Ti18+ was measured employing the merged electron-ion beams technique at a heavy-ion storage ring. The experimental electron-ion collision energy range 0-80 eV comprises all dielectronic recombination (DR) resonances ... More
Simulations of non-axisymmetric rotational core collapseNov 11 1997We report on the first three-dimensional hydrodynamic simulations of secular and dynamical non-axisymmetric instabilities in collapsing, rapidly rotating stellar cores which extend well beyond core bounce. The resulting gravitational radiation has been ... More
Interaction-induced Renormalization of Andreev ReflectionAug 01 2006We analyze the charge transport between a one-dimensional weakly interacting electron gas and a superconductor within the scaling approach in the basis of scattering states. We derive the renormalization group equations, which fully account for the intrinsic ... More
The secondary structure of RNA under tensionJun 18 2002Oct 07 2002We study the force-induced unfolding of random disordered RNA or single-stranded DNA polymers. The system undergoes a second order phase transition from a collapsed globular phase at low forces to an extensive necklace phase with a macroscopic end-to-end ... More
Nature of the glassy phase of RNA secondary structureAug 23 2001Mar 04 2002We characterize the low temperature phase of a simple model for RNA secondary structures by determining the typical energy scale E(l) of excitations involving l bases. At zero temperature, we find a scaling law E(l) \sim l^\theta with \theta \approx 0.23, ... More
Axisymmetric simulations of magneto--rotational core collapse: dynamics and gravitational wave signalOct 06 2005Feb 08 2006We have performed a comprehensive parameter study of the collapse of rotating, strongly magnetized stellar cores in axisymmetry to determine their gravitational wave signature based on the Einstein quadrupole formula. We use a Newtonian explicit magnetohydrodynamic ... More
The central role of line tension in the fusion of biological membranesApr 08 2005Apr 21 2005Recent progress in the fusion of biological membranes is reviewed to highlight the central role played by the line tension, which permits exquisite control of the process.
[The Impact of Nuclear Star Formation on Gas Inflow to AGNNov 23 2009Our adaptive optics observations of nearby AGN at spatial resolutions as small as 0.085arcsec show strong evidence for recent, but no longer active, nuclear star formation. We begin by describing observations that highlight two contrasting methods by ... More
Glassy phases in Random Heteropolymers with correlated sequencesJan 09 2004We develop a new analytic approach for the study of lattice heteropolymers, and apply it to copolymers with correlated Markovian sequences. According to our analysis, heteropolymers present three different dense phases depending upon the temperature, ... More
New mechanism of membrane fusionOct 10 2001We have carried out Monte Carlo simulation of the fusion of bilayers of single chain amphiphiles which show phase behavior similar to that of biological lipids. The fusion mechanism we observe is very different from the ``stalk'' hypothesis. Stalks do ... More
The Phase Diagram of Random HeteropolymersJul 02 2003May 10 2004We propose a new analytic approach to study the phase diagram of random heteropolymers, based on the cavity method. For copolymers we analyze the nature and phenomenology of the glass transition as a function of sequence correlations. Depending on these ... More
Millimeter Wave and Terahertz Spectra and Global Fit of Torsion-Rotation Transitions in the Ground, First and Second Excited Torsional States of 13CH3OH MethanolJun 24 2014Jul 01 2014Methanol is observed in a wide range of astrophysical sources throughout the universe, and comprehensive databases of the millimeter and THz spectra of CH3OH and its principal isotopologues represent important tools for the astronomical community. A previous ... More