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Electron gun for diffraction experiments off controlled moleculesJul 09 2015Sep 25 2015A dc electron gun, generating picosecond pulses with up to $8\times10^{6}$ electrons per pulse, was developed. Its applicability for future time-resolved-diffraction experiments on state- and conformer-selected laser-aligned or oriented gaseous samples ... More

Strongly aligned and oriented molecular samples at a kHz repetition rateJan 09 2013May 23 2013We demonstrate strong adiabatic laser alignment and mixed-field orientation at kHz repetition rates. We observe degrees of alignment as large as cos\Theta=0.94 at 1 kHz operation for iodobenzene. The experimental setup consist of a kHz laser system simultaneously ... More

Two-state wave packet for strong field-free molecular orientationSep 09 2014Jan 25 2015We demonstrate strong laser-field-free orientation of absolute-ground-state carbonyl sulfide molecules. The molecules are oriented by the combination of a 485-ps-long non-resonant laser pulse and a weak static electric field. The edges of the laser pulse ... More

Photophysics of indole upon x-ray absorptionFeb 08 2018A photofragmentation study of gas-phase indole (C$_8$H$_7$N) upon single-photon ionization at a photon energy of 420 eV is presented. Indole was primarily inner-shell ionized at its nitrogen and carbon $1s$ orbitals. Electrons and ions were measured in ... More

Background field and time dependence effects in holographic modelsOct 27 2014This thesis deals with applications of holographic dualities to the study of background field and time dependence effects in strongly coupled field theories. The first chapters (2-5) aim to provide a self-contained review of the Sakai-Sugimoto model (SSM) ... More

A study of the Gribov-Zwanziger action: from propagators to glueballsApr 07 2011This Ph.D. thesis presents a study of the Gribov-Zwanziger framework: from propagators to glueballs. The chapters 2 and 3 are meant as an introduction and only require a basic knowledge of quantum field theory. Chapter 2 explains the techniques behind ... More

Political Problems Facing Governments in Using Scientific Advice, and Legal and Other Problems Facing Scientists when Trying to Give Independent Advice to GovernmentsApr 21 2008It is the role of the scientific community to provide for the knowledge of scientific facts and technical capabilities as a background for political decision-making. The reasons are given why governments are sometimes not ready to accept well-founded ... More

Orbital Correlations in the Ferromagnetic Half-Metal $CrO_{2}Jan 22 2001We deduce a model relevant for the description of the ferromagnetic half-metal Chromium dioxide ($CrO_{2}$), widely used in magnetic recording technology. The model describes the effect of dynamical, local orbital correlations arising from local quantum ... More

Orbital selective insulator-metal transition in V2O3 under external pressureMay 12 2005We present a detailed account of the physics of Vanadium sesquioxide (${\rm V_2O_3}$), a benchmark system for studying correlation induced metal-insulator transition(s). Based on a detailed perusal of a wide range of experimental data, we stress the importance ... More

VO2: a two-fluid incoherent metal?Sep 01 2004We present {\it ab initio} LDA+DMFT results for the many-particle density of states of $VO_{2}$ on the metallic side of the strongly first-order ($T$-driven) insulator-metal transition. In strong contrast to LDA predictions, there is {\it no} remnant ... More

Towards a Fully Ab-Initio Description of the Diluted Magnetic Semiconductor $Ga_{1-x}Mn_{x}As$. Ferromagnetism, Electronic Structure, and Optical ResponseMar 20 2003There are two competing views of itinerant ferromagnetism, the first viewing ferromagnetism as resulting from the indirect coupling between local moments via the itinerant carrier dynamics, the so-called RKKY mechanism, while in the alternative picture, ... More

Orbital Switching and the First-Order Insulator-Metal Transition in Paramagnetic V_2O_3Nov 11 2002The first-order metal-insulator transition (MIT) in paramagnetic $V_{2}O_{3}$ is studied within the ab-initio scheme LDA+DMFT, which merges the local density approximation (LDA) with dynamical mean field theory (DMFT). With a fixed value of the Coulomb ... More

Role of Orbital Degeneracy in Double Exchange SystemsJul 11 2000We investigate the role of orbital degeneracy in the double exchange (DE) model. In the $J_{H}\to\infty$ limit, an effective generalized ``Hubbard'' model incorporating orbital pseudospin degrees of freedom is derived. The model possesses an exact solution ... More

Disordered Hubbard model in $d=\infty$Nov 23 1999We investigate the effects of static, diagonal disorder in the $d=\infty$ Hubbard model by treating the dynamical effects of local Hubbard correlations and disorder on an equal footing. This is achieved by a proper combination of the iterated perturbation ... More

Dijet angular distributions at $\sqrt{s}=14$ TeVMay 25 2009Nov 24 2009We present a Monte Carlo study of dijet angular distributions at $\sqrt{s}=14$ TeV. First we perform a next-to-leading order QCD study; we calculate the distributions in four different bins of dijet invariant mass using different Monte Carlo programs ... More

A magnetic instability of the non-Abelian Sakai-Sugimoto modelSep 19 2013Dec 10 2013In this follow-up paper of 1105.2217 we further discuss the occurrence of a magnetically induced tachyonic instability of the rho meson in the two-flavour Sakai-Sugimoto model, uplifting two remaining approximations in the previous paper. That is, firstly, ... More

Dynamical correlations in half-metallic manganitesOct 11 2001Motivated by the recent optical and photoemission measurements on half-metallic ferromagnetic three-dimensional manganites, we combine a tight-binding fit of the one-particle bandstructure with the dynamical mean-field theory, which treats the dynamical ... More

A new stellar mixing process operating below shell convection zones following off-center ignitionAug 22 2011During most stages of stellar evolution the nuclear burning of lighter to heavier elements results in a radial composition profile which is stabilizing against buoyant acceleration, with light material residing above heavier material. However, under some ... More

On the heavy-fermion behavior of the pyrochlore transition-metal oxide $LiV_{2}O_{4}$Feb 28 2002Motivated by the heavy fermion Fermi liquid (HFFL) features observed at low-$T$ in the pyrochlore $LiV_{2}O_{4}$, we consider a material-specific model that includes aspects of the local quantum chemistry, the geometrically frustrated lattice structure, ... More

Insulator-Metal transition in the Doped 3d1 Transition Metal Oxide LaTiO3Sep 16 2003The doping induced insulator-metal transition in $La_{1-x}Sr_{x}TiO_{3}$ is studied using the ab-initio LDA+DMFT method. Combining the LDA bandstructure for the actual, distorted structure found recently with multi-orbital DMFT to treat electronic correlations, ... More

Insulator-Metal Transition in the Rutile-based VO2May 05 2003May 12 2005The metal-insulator transition (MIT) in paramagnetic VO2 is studied within LDA+DMFT(IPT), which merges the local density approximation (LDA) with dynamical mean field theory (DMFT). With a fixed value of the Coulomb U=5.0eV, we show how the MIT is understood ... More

Exploring the Long-Term Evolution of GRS 1915+105Nov 04 2016Among the population of known galactic black hole X-ray binaries, GRS 1915+105 stands out in multiple ways. It has been in continuous outburst since 1992, and has shown a wide range of different states that can be distinguished by their timing and spectral ... More

Metallizing the Mott insulator TiOCl by electron doping: a view from LDA+DMFTOct 19 2004Based on recent experiments, we describe the Mott insulating, but undimerized state of $TiOCl$ using the local-density approximation combined with multi-orbital dynamical mean field theory (LDA+DMFT) for this $3d^{1}$ system.Good agreement with the high ... More

The spectroscopic parameters of sodium cyanide, NaCN (X 1A'), revisitedJan 03 2012The study of the rotational spectrum of NaCN (X 1A') has recently been extended in frequency and in quantum numbers. Difficulties have been encountered in fitting the transition frequencies within experimental uncertainties. Various trial fits traced ... More

Re-examining the Verwey transition in Fe3O4Nov 16 2005Motivated by recent structural data questioning the adequacy of the charge order (CO)/disorder picture for the Verwey transition (at T=T_V) in magnetite, we re-investigate this issue within a new theoretical picture. Using the state-of-the-art LDA+DMFT ... More

Orbital Kondo Effect in $CrO_{2}$: A LSDA+DMFT StudySep 05 2002Motivated by a collection of experimental results indicating the strongly correlated nature of the ferromagnetic metallic state of $CrO_{2}$, we present results based on a combination of the actual bandstructure [3] with dynamical mean-field theory (DMFT) ... More

Temperature dependence of the slip length in polymer melts at attractive surfacesApr 05 2008Using Couette and Poiseuille flow, we extract the temperature dependence of the slip length, $\delta$, from molecular dynamics simulations of a coarse-grained polymer model in contact with an attractive, corrugated surface. $\delta$ is dictated by the ... More

Inter-molecular structure factors of macromolecules in solution: integral equation resultsApr 19 1999The inter-molecular structure of semidilute polymer solutions is studied theoretically. The low density limit of a generalized Ornstein-Zernicke integral equation approach to polymeric liquids is considered. Scaling laws for the dilute-to-semidilute crossover ... More

Ideal quantum glass transitions: many-body localization without quenched disorderSep 04 2013Nov 06 2013We explore the possibility for translationally invariant quantum many-body systems to undergo a dynamical glass transition, at which ergodicity and translational invariance break down spontaneously, driven entirely by quantum effects. In contrast to analogous ... More

Statics and dynamics of a cylindrical droplet under an external body forceAug 14 2007We study the rolling and sliding motion of droplets on a corrugated substrate by Molecular Dynamics simulations. Droplets are driven by an external body force (gravity) and we investigate the velocity profile and dissipation mechanisms in the steady state. ... More

Lattice gluodynamics computation of Landau-gauge Green's functions in the deep infraredJan 07 2009May 14 2009We present recent results for the Landau-gauge gluon and ghost propagators in SU(3) lattice gluodynamics obtained on a sequence of lattices with linear extension ranging from L=64 to L=96 at $\beta = 5.70$, thus reaching "deep infrared" momenta down to ... More

The Landau gauge gluon and ghost propagators in 4D SU(3) gluodynamics in large lattice volumesOct 10 2007Mar 21 2008We present recent results of the Landau gauge gluon and ghost propagators in SU(3) pure gauge theory at Wilson \beta=5.7 for lattice sizes up to 80^4 corresponding to physical volumes up to (13.2 fm)^4. In particular, we focus on finite-volume and Gribov ... More

Running alpha(s) from Landau-gauge gluon and ghost correlationsOct 16 2007We estimate the running coupling constant of the strong interactions within the nonperturbative framework of lattice QCD in Landau gauge. Our calculation is based on the ghost-gluon vertex which in the particular case of Landau gauge allows for a definition ... More

Cyclic motion and inversion of surface flow direction in a dense polymer brush under shearAug 30 2007Using molecular simulations, we study the properties of a polymer brush in contact with an explicit solvent under Couette and Poiseuille flow. The solvent is comprised of chemically identical chains. We present evidence that individual, unentangled chains ... More

The Landau gauge gluon propagator in 4D SU(2) lattice gauge theory revisited: Gribov copies and scaling propertiesDec 11 2009Lattice results for the gluon propagator in SU(2) pure gauge theory obtained on large lattices are presented. Simulated annealing is used throughout to fix the Landau gauge. We concentrate on checks for Gribov copy effects and for scaling properties. ... More

Lattice study of the infrared behavior of QCD Green's functions in Landau gaugeOct 09 2006We summarize the current status of our numerical results for the gluon and ghost propagators and for the Kugo-Ojima confinement parameter in quenched SU(3) lattice Landau gauge theory. The data for the propagators are compared to our results obtained ... More

Spin noise spectroscopy under resonant optical probing conditions: coherent and non-linear effectsAug 02 2011Sep 20 2011High sensitivity Faraday rotation spectroscopy is used to measure the fluctuating magnetization noise of non-interacting rubidium atoms under resonant and non-resonant optical probing conditions. The spin noise frequency spectra in dependence on the probe ... More

The mass function of the Las Campanas loose groups of galaxiesFeb 18 2002Oct 23 2002We have determined the mass function of loose groups of galaxies in the Las Campanas Redshift Survey. Loose groups of galaxies in the LCRS range in mass from $M \sim 10^{12} {\rm M}_{\sun}$ to $10^{15} {\rm M}_{\sun}$. We find that the sample is almost ... More

Landau Gauge Gluon and Ghost Propagators from Lattice QCDSep 25 2006Nov 06 2006We report on recent numerical computations of the Landau gauge gluon and ghost propagators as well as of the ghost-gluon vertex function in pure SU(3) Yang-Mills theory and in full QCD on the lattice. Special emphasis is paid to the low momentum region. ... More

Twisted mass QCD at finite temperatureOct 02 2007We discuss the use of Wilson fermions with twisted mass for simulations of QCD thermodynamics. As a prerequisite for a future analysis of the finite-temperature transition making use of automatic O(a) improvement, we investigate the phase structure in ... More

Perspective Functions: Proximal Calculus and Applications in High-Dimensional StatisticsOct 05 2016Oct 13 2016Perspective functions arise explicitly or implicitly in various forms in applied mathematics and in statistical data analysis. To date, no clear systematic strategy is available to solve the associated, typically nonsmooth, optimization problems. In this ... More

Integration and characterization of solid wall electrodes in microfluidic devices fabricated in a single photolithography stepMay 15 2013We describe the fabrication and characterization of solid 3-dimensional electrodes in direct contact with microfluidic channels, implemented using a single photolithography step, allowing operation in high-dielectric constant media. Incorporation and ... More

Las Campanas Loose Groups in the Supercluster-Void NetworkMay 14 2003We study the spatial distribution of loose groups from the Las Campanas Redshift Survey, comparing it with the supercluster-void network delineated by rich clusters of galaxies. We use density fields and the friends-of-friends algorithm to identify the ... More

Phase structure of thermal lattice QCD with N_f=2 twisted mass Wilson fermionsMay 19 2009Nov 04 2009We present numerical results for the phase diagram of lattice QCD at finite temperature in the formulation with twisted mass Wilson fermions and a tree-level Symanzik-improved gauge action. Our simulations are performed on lattices with temporal extent ... More

The finite-temperature phase structure of lattice QCD with twisted-mass Wilson fermionsSep 30 2008Oct 13 2008We report progress in our exploration of the finite-temperature phase structure of two-flavour lattice QCD with twisted-mass Wilson fermions and a tree-level Symanzik-improved gauge action for a temporal lattice size N_{\tau}=8. Extending our investigations ... More

The spin-$\frac{1}{2}$ XXZ chain system Cs$_2$CoCl$_4$ in a transverse magnetic fieldJul 10 2013Comparing high-resolution specific heat and thermal expansion measurements to exact finite-size diagonalization, we demonstrate that Cs$_2$CoCl$_4$ for a magnetic field along the crystallographic b axis realizes the spin-$\frac{1}{2}$ XXZ chain in a transverse ... More

Galaxy morphology, luminosity and, environment in the SDSS DR7Dec 07 2010Mar 11 2011We study the influence of the environment on the evolution of galaxies by investigating the luminosity function (LF) of galaxies of different morphological types and colours at different environmental density levels. We construct the LFs separately for ... More

Environmental Enhancement of Loose Groups around Rich Clusters of GalaxiesNov 27 2002We have studied the properties of Las Campanas Loose Groups in the neighbourhood of rich (Abell, APM and X-ray) clusters of galaxies. These loose groups show strong evidence of segregation measured in terms of the group richness and the group velocity ... More

Dipolar Stabilization of an Attractive Bose Gas in a One Dimensional LatticeMay 25 2011We experimentally show that dipolar interaction can stabilize otherwise unstable many-body systems like an attractive Bose gas. In a one dimensional lattice the repulsive dipolar on-site interaction balances negative scattering lengths up to -17 Bohr ... More

Structure and decay of rotating homogeneous turbulenceJun 04 2009Navier-Stokes turbulence subject to solid-body rotation is studied by high-resolution direct numerical simulations (DNS) of freely decaying and stationary flows. Setups characterized by different Rossby numbers are considered. In agreement with experimental ... More

Zero distribution of complex orthogonal polynomials with respect to exponential weightsDec 16 2013We study the limiting zero distribution of orthogonal polynomials with respect to some particular exponential weights exp(-nV(z)) along contours in the complex plane. We are especially interested in the question under which circumstances the zeros of ... More

The No-Pole Condition in Landau gauge: Properties of the Gribov Ghost Form-Factor and a Constraint on the 2d Gluon PropagatorFeb 09 2012We study the Landau-gauge Gribov ghost form-factor sigma(p^2) for SU(N) Yang-Mills theories in the d-dimensional case. We find a qualitatively different behavior for d=3,4 w.r.t. d=2. In particular, considering any (sufficiently regular) gluon propagator ... More

Unitarity analysis of a non-Abelian gauge invariant action with a massMay 07 2007In previous work done by us and coworkers, we have been able to construct a local, non-Abelian gauge invariant action with a mass parameter, based on the nonlocal gauge invariant mass dimension two operator F1/D^2F. The renormalizability of the resulting ... More

Holographic study of rho meson mass in an external magnetic field: paving the road towards a magnetically induced superconducting QCD vacuum?Feb 15 2011Feb 18 2011We study the rho meson mass in a uniform background magnetic field eB at zero temperature, in search of indications for the magnetically induced rho meson condensation, as predicted recently by Chernodub. The holographic model used is the Sakai-Sugimoto ... More

Dephasing-assisted Gain and Loss in Mesoscopic Quantum SystemsAug 15 2016Motivated by recent experiments, we analyse the phonon-assisted steady-state gain of a microwave field driving a double quantum-dot in a resonator. We apply the results of our companion paper, which derives the complete set of fourth-order Lindblad dissipators ... More

Localization in coupled heterogeneously disordered transport channels on the Bethe latticeFeb 26 2013Mar 29 2013We study the Anderson localization in systems, in which transport channels with rather different properties are coupled together. This problem arises naturally in systems of hybrid particles, such as exciton-polaritons, where it is not obvious which transport ... More

Equivalence of Emergent de Sitter Spaces from Conformal Field TheoryApr 10 2016Aug 02 2016Recently, two groups have made distinct proposals for a de Sitter space that is emergent from conformal field theory (CFT). The first proposal is that, for two-dimensional holographic CFTs, the kinematic space of geodesics on a spacelike slice of the ... More

Synthesising Keldysh and Lindblad - Correlated decay processes in higher order perturbation theoryAug 15 2016Motivated by correlated decay processes driving gain, loss and lasing in driven semiconductor quantum-dots, we develop a theoretical technique using Keldysh diagrammatic perturbation theory to derive a Lindblad master equation that goes beyond the usual ... More

Imaging Molecular Structure through Femtosecond Photoelectron Diffraction on Aligned and Oriented Gas-Phase MoleculesJul 29 2014This paper gives an account of our progress towards performing femtosecond time-resolved photoelectron diffraction on gas-phase molecules in a pump-probe setup combining optical lasers and an X-ray Free-Electron Laser. We present results of two experiments ... More

Spin-polarizing interferometric beam splitter for free electronsJul 29 2016A spin-polarizing electron beam splitter is described which relies on an arrangement of linearly polarized laser waves of nonrelativistic intensity. An incident electron beam is first coherently scattered off a bichromatic laser field, splitting the beam ... More

Kapitza-Dirac scattering of electrons from a bichromatic standing laser waveMar 12 2015Aug 05 2016Coherent scattering of an electron beam by the Kapitza-Dirac effect from a standing laser wave which comprises two frequency components is studied. To this end, the Schr\"odinger equation is solved numerically with a suitable ponderomotive potential. ... More

Factorization of the Schrödinger Operator and the Riccati Equation in the Clifford Analysis SettingJan 25 2010This paper is devoted to a factorization of the higher dimensional Schrodinger operator in the framework of Clifford analysis.

The fractional Clifford-Fourier transformSep 26 2012In this paper, a fractional version of the Clifford-Fourier transform is introduced, depending on two numerical parameters. A series expansion for the kernel of the resulting integral transform is derived. In the case of even dimension, also an explicit ... More

Acoustic tests of Lorentz symmetry using Bulk Acoustic Wave quartz oscillatorsJul 25 2016Aug 07 2016A new method of probing Lorentz invariance in the neutron sector is described. The method is baed on stable quartz bulk acoustic wave oscillators compared on a rotating table. Due to Lorentz-invariance violation, the resonance frequencies of acoustic ... More

Lattice results on gluon and ghost propagators in Landau gaugeApr 08 2008We present clear evidence of strong effects of Gribov copies in Landau gauge gluon and ghost propagators computed on the lattice at small momenta by employing a new approach to Landau gauge fixing and a more effective numerical algorithm. It is further ... More

The Landau gauge gluon propagator: Gribov problem and finite-size effectsOct 17 2007The SU(2) gluon propagator in Landau gauge is studied on the lattice. Our gauge fixing procedure employs simulated annealing and Z(2)-flips. It finds higher maxima of the gauge functional compared with those obtained with the standard overrelaxation and ... More

Angular Dependent Soft X-ray Absorption Spectroscopy of V2O5 and V6O13Sep 22 1994We have measured the V 2p3/2 and O 1s x-ray absorption spectra of single crystal V2O5 and V6O13 and compared to linear combinations of atomic orbitals (LCAO) density of states (DOS) calculations. The spectra change dramatically with incident angle. The ... More

Large size and slow rotation of the trans-Neptunian object (225088) 2007 OR10 discovered from Herschel and K2 observationsMar 09 2016We present the first comprehensive thermal and rotational analysis of the second most distant trans-Neptunian object (225088) 2007 OR10. We combined optical light curves provided by the Kepler space telescope -- K2 extended mission and thermal infrared ... More

Generalized Stability Approach for Regularized Graphical ModelsMay 23 2016Selecting regularization parameters in penalized high-dimensional graphical models in a principled, data-driven, and computationally efficient manner continues to be one of the key challenges in high-dimensional statistics. We present substantial computational ... More

Improved Landau gauge fixing and the suppression of finite-volume effects of the lattice gluon propagatorJul 24 2007Jan 15 2008For the gluon propagator of pure SU(2) lattice gauge theory in the Landau gauge we investigate the effect of Gribov copies and finite-volume effects. Concerning gauge fixing, we enlarge the accessible gauge orbits by adding non-periodic Z(2) gauge transformations ... More

Low-temperature ordered phases of the spin-$\frac{1}{2}$ XXZ chain system Cs$_2$CoCl$_4$Dec 09 2014In this study the magnetic order of the spin-1/2 XXZ chain system Cs$_2$CoCl$_4$ in a temperature range from 50 mK to 0.5 K and in applied magnetic fields up to 3.5 T is investigated by high-resolution measurements of the thermal expansion and the specific ... More

Prominent role of multi-electron processes in K-shell double and triple photodetachment of oxygen anionsSep 17 2016The photon-ion merged-beams technique was used at a synchrotron light source for measuring absolute cross sections of double and triple photodetachment of O$^{-}$ ions. The experimental photon energy range of 524-543 eV comprised the threshold for K-shell ... More

Transversality and lattice surgery: exploring realistic routes towards coupled logical qubits with trapped-ion quantum processorsJan 22 2018Active quantum error correction has been identified as a crucial ingredient of future quantum computers, motivating the recent experimental efforts to encode logical quantum bits using small topological codes. In addition to the demonstration of the beneficial ... More

Special functions and systems in Hermitian Clifford analysisMay 24 2012In this paper we study some new special functions that arise naturally within the framework of Hermitian Clifford analysis, which concerns the study of Dirac-like systems in several complex variables. In particular we focus on Hermite polynomials, Bessel ... More

A renormalization group invariant scalar glueball operator in the (Refined) Gribov-Zwanziger frameworkJun 23 2009This paper presents a complete algebraic analysis of the renormalizability of the $d=4$ operator $F^2_{\mu\nu}$ in the Gribov-Zwanziger (GZ) formalism as well as in the Refined Gribov-Zwanziger (RGZ) version. The GZ formalism offers a way to deal with ... More

Picard-Fuchs equations, Integrable Systems, and higher Algebraic K-theoryJul 22 2002Feb 09 2003This paper continues our previous work done in math.AG/0008207 and is an attempt to establish a conceptual framework which generalizes the work of Manin on the relation between non-linear second order ODEs of type Painleve VI and integrable systems. The ... More

Photoionization of tungsten ions: experiment and theory for W$^{2+}$ and W$^{3+}$Dec 18 2015Experimental and theoretical results are reported for single-photon single ionization of W$^{2+}$ and W$^{3+}$ tungsten ions. Experiments were performed at the photon-ion merged-beam setup of the Advanced Light Source in Berkeley. Absolute cross sections ... More

Convolution products for hypercomplex Fourier transformsMar 07 2013Hypercomplex Fourier transforms are increasingly used in signal processing for the analysis of higher-dimensional signals such as color images. A main stumbling block for further applications, in particular concerning filter design in the Fourier domain, ... More

Local simulations of the magnetized Kelvin-Helmholtz instability in neutron-star mergersMar 31 2010Context. Global MHD simulations show Kelvin-Helmholtz (KH) instabilities at the contact surface of two merging neutron stars. That region has been identified as the site of efficient amplification of magnetic fields. However, these global simulations, ... More

L^p-spectral multipliers for the Hodge Laplacian acting on 1-forms on the Heisenberg groupAug 27 2005We prove that, if \Delta_1 is the Hodge Laplacian acting on differential 1-forms on the (2n+1)-dimensional Heisenberg group, and if m is a Mihlin-H\"ormander multiplier on the positive half-line, with L^2-order of smoothness greater than n+1/2, then m(\Delta_1) ... More

On the Origin of the Non-Fermi Liquid Behavior of SrRuO_{3}Apr 27 2001Motivated by the unusual features observed in the transport properties of the ferromagnetic "bad metal" $SrRuO_{3}$, we construct a model incorporating essential features of the realistic structure of this nearly cubic material. In particular, we show ... More

Resonant scattering induced thermopower in one-dimensional disordered systemsMar 12 2015This study analyzes thermoelectric properties of a one-dimensional random conductor which shows localization effects and simultaneously includes resonant scatterers yielding sharp conductance resonances. These sharp features give rise to a distinct behavior ... More

Large Time Existence for Thin Vibrating PlatesSep 15 2009Jan 05 2011We construct strong solutions for a nonlinear wave equation for a thin vibrating plate described by nonlinear elastodynamics. For sufficiently small thickness we obtain existence of strong solutions for large times under appropriate scaling of the initial ... More

Luminosity function and density field of the Sloan and Las Campanas Redshift SurveyDec 13 2002The luminosity function of galaxies of the Early Data Release of the Sloan Digital Sky Survey (SDSS) and the Las Campanas Redshift Survey (LCRS) is calculated. The luminosity function depends on redshift, density of the environment and is different for ... More

Spectroscopic study and astronomical detection of doubly 13C-substituted ethyl cyanideApr 12 2016We have performed a spectral line survey called EMoCA toward Sagittarius B2(N) between 84 and 114 GHz with ALMA. Line intensities of the main isotopic species of ethyl cyanide and its singly 13C-substituted isotopomers observed toward the hot molecular ... More

Re-entrant superconductivity in Nb/Cu(1-x)Ni(x) bilayersFeb 19 2006We report on the first observation of a pronounced re-entrant superconductivity phenomenon in superconductor/ferromagnetic layered systems. The results were obtained using a superconductor/ferromagnetic-alloy bilayer of Nb/Cu(1-x)Ni(x). The superconducting ... More

Upper critical field and irreversibility line in superconducting MgB_2Apr 05 2001The upper critical field Hc2(T) of sintered pellets of the recently discovered MgB_2 superconductor was investigated by transport, ac susceptibility and dc magnetization measurements in magnetic fields up to 16 T covering a temperature range between Tc ... More

Confinement-induced collapse of a dipolar Bose-Einstein condensateMay 23 2012We report on the observation of the confinement-induced collapse dynamics of a dipolar Bose-Einstein condensate (dBEC) in a one-dimensional optical lattice. We show that for a fixed interaction strength the collapse can be initiated in-trap by lowering ... More

Analysis of the Hodge Laplacian on the Heisenberg groupJun 20 2012We consider the Hodge Laplacian $\Delta$ on the Heisenberg group $H_n$, endowed with a left-invariant and U(n)-invariant Riemannian metric. For $0\le k\le 2n+1$, let $\Delta_k$ denote the Hodge Laplacian restricted to $k$-forms. Our first main result ... More

An experimental approach for investigating many-body phenomena in Rydberg-interacting quantum systemsJul 03 2013Recent developments in the study of ultracold Rydberg gases demand an advanced level of experimental sophistication, in which high atomic and optical densities must be combined with excellent control of external fields and sensitive Rydberg atom detection. ... More

Spectroscopic parameters for silacyclopropynylidene, SiC2, from extensive astronomical observations toward CW Leo (IRC +10216) with the Herschel satelliteDec 01 2011A molecular line survey has been carried out toward the carbon-rich asymptotic giant branch star CW Leo employing the HIFI instrument on board of the Herschel satellite. Numerous features from 480 GHz to beyond 1100 GHz could be assigned unambiguously ... More

Herschel and IRAM-30m Observations of Comet C/2012 S1 (ISON) at 4.5 AU from the SunNov 25 2013Our goal was to characterize the distant gaseous and dust activity of comet C\2012 S1 (ISON), inbound, from observations of H2O, CO and the dust coma in the far-infrared and submillimeter domains. In this paper, we report observations undertaken with ... More

Research Challenges in Management and Compliance of Policies on the WebJul 30 2008In this paper we argue that policies are an increasing concern for organizations that are operating a web site. Examples of policies that are relevant in the domain of the web address issues such as privacy of personal data, accessibility for the disabled, ... More

On the Normal State Electronic properties of Layered Sr_2 RuO_4Aug 28 2002Based on a comprehensive perusal of experimental results, we construct a microscopic model describing the normal state of layered 4d oxide Sr_2 RuO_4 incorporating relevant quantum chemical features of the material. The high-T anomalies are explained ... More

Relativistic Theory of Hydrodynamic Fluctuations with Applications to Heavy Ion CollisionsDec 29 2011Jan 10 2012We develop the relativistic theory of hydrodynamic fluctuations for application to high energy heavy ion collisions. In particular, we investigate their effect on the expanding boost-invariant (Bjorken) solution of the hydrodynamic equations. We discover ... More

Thermalization of a strongly interacting 1D Rydberg lattice gasJul 25 2009Feb 15 2010When Rydberg states are excited in a dense atomic gas the mean number of excited atoms reaches a stationary value after an initial transient period. We shed light on the origin of this steady state that emerges from a purely coherent evolution of a closed ... More

Anomalous Viscosity of an Expanding Quark-Gluon PlasmaMar 12 2006Jun 20 2006We argue that an expanding quark-gluon plasma has an anomalous viscosity, which arises from interactions with dynamically generated color fields. We derive an expression for the anomalous viscosity in the turbulent plasma domain and apply it to the hydrodynamic ... More

Operator formalism for topology-conserving crossing dynamics in planar knot diagramsOct 07 2014We address here the topological equivalence of knots through the so-called Reidemeister moves. These topology-conserving manipulations are recast into dynamical rules on the crossings of knot diagrams. This is presented in terms of a simple graphical ... More

Orbit of the young very low-mass spectroscopic binary CHXR 74Nov 03 2011Nov 08 2011The pre-main sequence star CHXR74 (M4.25) in ChaI was detected a few years ago to be a very low-mass spectroscopic binary. Determination of its mass would provide a valuable dynamical mass measurement at young ages in the poorly constrained mass regime ... More

The sulfur depletion problem: upper limits on the H2S2, HS2, and S2 gas-phase abundances toward the low-mass warm core IRAS16293-2422Jan 11 2016A fraction of the missing sulfur in dense clouds and circumstellar regions could be in the form of three species not yet de- tected in the interstellar medium: H2S2, HS2, and S2 according to experimental simulations performed under astrophysically relevant ... More