Results for "D. Jullien"

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Magnetic induction and domain walls in magnetic thin films at remanenceMay 25 2004Feb 27 2005Magnetic domain walls in thin films can be well analyzed using polarized neutron reflectometry. Well defined streaks in the off-specular spin-flip scattering maps are explained by neutron refraction at perpendicular N\'{e}el walls. The position of the ... More
A Preliminary Theory for Open Source Ecosystem Micro-economicsMay 15 2019While there has been substantial empirical work identifying factors that influence the contribution to, and use of open source software, we have as yet little theory that identifies the key constructs and relationships that would allow us to explain and ... More
Constraining short-range spin-dependent forces with polarized helium 3 at the Laue-Langevin InstituteOct 09 2015We have searched for a short-range spin-dependent interaction mediated by a hypothetical light scalar boson with CP-violating couplings to the neutron using the spin relaxation of hyperpolarized $^3$He. The walls of the $^3$He cell would generate a depolarizing ... More
Polarized 3He as a probe for short-range spin-dependent interactionsSep 17 2010Oct 19 2010We have studied the relaxation of a spin-polarized gas in a magnetic field, in the presence of short-range spin-dependent interactions. As a main result we have established a link between the specific properties of the interaction and the dependence of ... More
Fractionalization of minimal excitations in integer quantum Hall edge channelsJan 28 2013A theoretical study of the single electron coherence properties of Lorentzian and rectangular pulses is presented. By combining bosonization and the Floquet scattering approach, the effect of interactions on a periodic source of voltage pulses is computed ... More
Integer and fractional charge Lorentzian voltage pulses analyzed in the frame of Photon-assisted Shot NoiseDec 17 2012Jan 29 2013The periodic injection $n$ of electrons in a quantum conductor using periodic voltage pulses applied on a contact is studied in the energy and time-domain using shot noise computation in order to make comparison with experiments. We particularly consider ... More
A project of advanced solid-state neutron polarizer for PF1B instrument at ILLJun 11 2019Among Super-Mirror (SM) polarizers, solid-state devices have many advantages. The most relevant is 5-10 times smaller length compared to air-gap polarizers allowing to apply stronger magnetic fields. An important condition for a good SM polarizer is the ... More
Advanced broad-band solid-state supermirror polarizers for cold neutronsJun 06 2016Jun 15 2016An ideal solid-state supermirror (SM) neutron polarizer assumes total reflection of neutrons from the SM coating for one spin-component and total absorption for the other, thus providing a perfectly polarized neutron beam at the exit. However, in practice, ... More
Percolation in Cluster-Cluster Aggregation ProcessesApr 12 1995Numerical simulations of Diffusion-Limited and Reaction-Limited Cluster-Cluster Aggregation processes of identical particles are performed in a two-dimensional box. It is shown that, for concentrations larger than a characteristic gel concentration, the ... More
The Sol-Gel Process Simulated by Cluster-Cluster AggregationApr 11 1995The pair-correlation function $g(r,t)$ and its Fourier transform, the structure factor $S(q,t)$, are computed during the gelation process of identical spherical particles using the diffusion-limited cluster-cluster aggregation model in a box. This numerical ... More
Relativistic electron beams driven by kHz single-cycle light pulsesNov 29 2016Laser-plasma acceleration is an emerging technique for accelerating electrons to high energies over very short distances. The accelerated electron bunches have femtosecond duration, making them particularly relevant for applications such as ultrafast ... More
Relativistic electron beams driven by kHz single-cycle light pulsesNov 29 2016Dec 02 2016Laser-plasma acceleration is an emerging technique for accelerating electrons to high energies over very short distances. The accelerated electron bunches have femtosecond duration, making them particularly relevant for applications such as ultrafast ... More
Dressed photon-orbital states in a quantum dot: Inter-valley spin resonanceAug 23 2016The valley degree of freedom is intrinsic to spin qubits in Si/SiGe quantum dots. It has been viewed alternately as a hazard, especially when the lowest valley-orbit splitting is small compared to the thermal energy, or as an asset, most prominently in ... More
Effect of the laser wavefront in a laser-plasma acceleratorJan 23 2015A high repetition rate electron source was generated by tightly focusing kHz, few-mJ laser pulses into an underdense plasma. This high intensity laser-plasma interaction led to stable electron beams over several hours but with strikingly complex transverse ... More
Non-Boltzmann classical correction to the velocity auto-correlation function for isotropic scattering in two dimensionsNov 26 2004The classical correction to the velocity auto-correlation function of non-interacting particles due to memory effects, which are beyond the Boltzmann equation, is calculated both analytically and numerically for the case of isotropic scattering in two ... More
Anomalous Low-Field Classical Magnetoresistance in Two DimensionsDec 09 2002The magnetoresistance of classical two-dimensional electrons scattered by randomly distributed impurities is investigated by numerical simulation. At low magnetic fields, we find for the first time a negative magnetoresistance proportional to |B|. This ... More
A clustering approach to infer Wikipedia contributors' profileMar 26 2018In online communities, recent studies have strongly improved our knowledge about the different types or profiles of contributors, from casual to very involved ones, through focused people. However they do so by using very complex methodologies (qualitative-quantitative ... More
Channel diffusion of sodium in a silicate glassJan 05 2001Jul 12 2001We use classical molecular dynamics simulations to study the dynamics of sodium atoms in amorphous Na$_2$O-4SiO$_2$. We find that the sodium trajectories form a well connected network of pockets and channels. Inside these channels the motion of the atoms ... More
A Numerical Study of Phase Transitions Inside the Pores of AerogelsApr 13 1995Phase transitions inside the pores of an aerogel are investigated by modelizing the aerogel structure by diffusion-limited cluster-cluster aggregation on a cubic lattice in a finite box and considering $q$-states Potts variables on the empty sites interacting ... More
Small Angle Scattering by Fractal Aggregates: A Numerical Investigation of the Crossover Between the Fractal Regime and the Porod RegimeApr 12 1995Fractal aggregates are built on a computer using off-lattice cluster-cluster aggregation models. The aggregates are made of spherical particles of different sizes distributed according to a Gaussian-like distribution characterised by a mean $a_0$ and ... More
Social Interactions vs Revisions, What is important for Promotion in Wikipedia?Jan 07 2015In epistemic community, people are said to be selected on their knowledge contribution to the project (articles, codes, etc.) However, the socialization process is an important factor for inclusion, sustainability as a contributor, and promotion. Finally, ... More
Vorticity statistics in the two-dimensional enstrophy cascadeApr 21 1999We report the first extensive experimental observation of the two-dimensional enstrophy cascade, along with the determination of the high order vorticity statistics. The energy spectra we obtain are remarkably close to the Kraichnan Batchelor expectation. ... More
Classical mechanism for negative magnetoresistance in two dimensionsMar 23 2001Oct 02 2001The classical two-dimensional problem of non-interacting electrons scattered by short-range impurity centers in the presence of magnetic field is investigated both analytically and numerically. A strong magnetoresistance exists in such a system, due to ... More
Gate fidelity and coherence of an electron spin in a Si/SiGe quantum dot with micromagnetFeb 26 2016The gate fidelity and the coherence time of a qubit are important benchmarks for quantum computation. We construct a qubit using a single electron spin in a Si/SiGe quantum dot and control it electrically via an artificial spin-orbit field from a micromagnet. ... More
Thermal/quantum effects and induced superstring cosmologiesOct 22 2007Apr 02 2009We consider classical superstring theories on flat four dimensional space-times, and where N=4 or N=2 supersymmetry is spontaneously broken. We obtain the thermal and quantum corrections at the string one-loop level and show that the back-reaction on ... More
AutocatalysesJun 14 2010Oct 22 2010Autocatalysis is a fundamental concept, used in a wide range of domains. From the most general definition of autocatalysis, that is a process in which a chemical compound is able to catalyze its own formation, several different systems can be described. ... More
Global sensitivity analysis for models with spatially dependent outputsNov 06 2009Sep 23 2010The global sensitivity analysis of a complex numerical model often calls for the estimation of variance-based importance measures, named Sobol' indices. Metamodel-based techniques have been developed in order to replace the cpu time-expensive computer ... More
Spinor-Vector Duality in Heterotic SUSY VacuaJul 25 2008We elaborate on the recently discovered spinor-vector duality in realistic free fermionic heterotic vacua. We emphasize the interpretation of the freely-acting orbifolds carried out on the six internal dimensions as coordinate-dependent compactifications; ... More
Thermal and quantum superstring cosmologiesMar 18 2008We consider four dimensional heterotic string backgrounds for which supersymmetry is spontaneously broken via the Scherk-Schwarz mechanism on an internal spatial cycle and by finite temperature effects. We concentrate on initially flat backgrounds with ... More
Structural and electronic properties of the sodium tetrasilicate glass Na${}_2$Si${}_4$O${}_9$ from classical and ab initio molecular-dynamics simulationsSep 14 2001Dec 20 2001The structure and the electronic properties of a sodium tetrasilicate (Na${}_2$Si${}_4$O${}_9$) glass were studied by combined Car-Parrinello and classical molecular-dynamics simulations. The glass sample was prepared using a method employed recently ... More
Constraining short-range spin-dependent forces with polarized $^3$HeNov 22 2015We have searched for a short-range spin-dependent interaction using the spin relaxation of hyperpolarized $^3$He. Such a new interaction would be mediated by a hypothetical light scalar boson with \CP-violating couplings to the neutron. The walls of the ... More
Induced superstring cosmologies and moduli stabilizationJan 02 2009Jun 07 2009We extend the analysis of the recently obtained stringy cosmological solutions induced by thermal and quantum effects, once space-time supersymmetry is spontaneously broken by geometrical fluxes. Cases in which more than one modulus participating in the ... More
Gas Transport in Porous Media: Simulations and Experiments on Partially Densified AerogelsApr 11 1995The experimental density dependence of gas (argon and nitrogen) permeability of partially densified silica aerogels in the Knudsen regime is quantitatively accounted for by a computer model. The model simulates both the structure of the sintered material ... More
Search for a new short-range spin-dependent force with polarized Helium 3Jan 30 2015Feb 02 2015Measuring the depolarization rate of a $^3$He hyperpolarized gas is a sensitive method to probe hypothetical short-range spin-dependent forces. A dedicated experiment is being set up at the Institute Laue Langevin in Grenoble to improve the sensitivity. ... More
Small Angle Neutron Scattering of Aerogels: Simulations and ExperimentsApr 12 1995A numerical simulation of silica aerogels is performed using diffusion-limited cluster-cluster aggregation of spheres inside a cubic box (with periodic boundary conditions). The volume fraction $c$ is taken to be sufficiently large to get a gel structure ... More
Coiling of Cylindrical Membrane Stacks with Anchored PolymersApr 23 1999Aug 01 1999We study experimentally a coiling instability of cylindrical multilamellar stacks of phospholipid membranes, induced by polymers with hydrophobic anchors grafted along their hydrophilic backbone. We interpret our experimental results in terms of a model, ... More
Influence of surfactants on the structure of titanium oxide gels : experiments and simulationsNov 22 1995We report here on experimental and numerical studies of the influence of surfactants on mineral gel synthesis. The modification of the gel structure when the ratios water-precursor and water-surfactant vary is brought to the fore by fractal dimension ... More
Scaling Theory and Numerical Simulations of Aerogel SinteringApr 11 1995A simple scaling theory for the sintering of fractal aerogels is presented. The densification at small scales is described by an increase of the lower cut-off length $a$ accompanied by a decrease of the upper cut-off length $\xi$, in order to conserve ... More
Ultrasound transmission through monodisperse 2D microfoamsJan 18 2019While the acoustic properties of solid foams have been abundantly characterized, sound propagation in liquid foams remains poorly understood. Recent studies have investigated the transmission of ultrasound through three-dimensional polydisperse liquid ... More
An Active Chaotic Micromixer Integrating Thermal Actuation Associating PDMS and Silicon MicrotechnologyNov 21 2007Due to scaling laws, in microfluidic, flows are laminar. Consequently, mixing between two liquids is mainly obtained by natural diffusion which may take a long time or equivalently requires centimetre length channels. To reduce time and length for mixing, ... More
Carrier-envelope-phase stable, high-contrast, double chirped-pulse-amplification laser systemFeb 05 2018We present the first carrier-envelope phase stable chirped pulse amplifier (CPA) featuring high temporal contrast for relativistic intensity laser-plasma interactions at 1 kHz repetition rate. The laser is based on a double-CPA architecture including ... More
Anticorrelated emission of high-harmonics and fast electron beams from plasma mirrorsFeb 01 2018We report for the first time on the anticorrelated emission of high-order harmonics and energetic electron beams from a solid-density plasma with a sharp vacuum interface$-$plasma mirror$-$driven by an intense ultrashort laser pulse. We highlight the ... More
Compression of CEP-stable multi-mJ laser pulses down to 4 fs in long hollow fibersFeb 02 2018Carrier envelope phase stable 4 fs near-IR pulses with 3 mJ energy were generated by spectral broadening of circularly polarized 8 mJ pulses in a differentially pumped 2 m long composite stretched exible hollow ber. The pulses were characterized using ... More
High-contrast Ultrabroadband Frontend Source for High Intensity Few-Cycle LasersSep 09 2011An ultrabroadband seed source for high-power, high-contrast OPCPA systems at 800 nm is presented. The source is based on post compression in a hollow-core fiber followed by crossed polarized waves (XPW) filtering and is capable of delivering 80$\mu$J, ... More
Carrier-envelope phase stability of hollow-fibers used for high-energy, few-cycle pulse generationAug 09 2013We investigated the carrier-envelope phase (CEP) stability of a hollow-fiber setup used for high-energy, few-cycle pulse generation. Saturation of the output pulse energy is observed at 0.6 mJ for a 260 um inner-diameter, 1 m long fiber, statically filled ... More
Inconsistence of super-luminal Cern-Opera neutrino speed with observed SN1987A burst and neutrino mixing for any imaginary neutrino massSep 25 2011Mar 05 2012We tried to fit in any way the recent Opera-Cern claims of a neutrino super-luminal speed with observed Supernova SN1987A neutrino burst and all (or most) neutrino flavor oscillation. We considered three main frame-works: (1) A tachyon imaginary neutrino ... More
Some surface subgroups survive surgeryApr 07 2001It is shown that with finitely many exceptions, the fundamental group obtained by Dehn surgery on a one cusped hyperbolic 3-manifold contains the fundamental group of a closed surface.
Cen A persistence and Virgo absence versus updated maps to understand UHECR natureDec 31 2010Ultra High Cosmic Rays (UHECR) should be tracing their sources, making a new astronomy. Their events counting are finally growing, by Auger experiment, into cosmic sky. Their map should follow the mass distribution in a narrow cosmic volume (the GZK cut ... More
Deep Core muon neutrino rate and anisotropy by mixing and CPT violationDec 23 2010Neutrinos are allowed to mix and to oscillate among their flavor. Muon and tau in particular oscillate at largest values.Last Minos experiment claimed possible difference among their matter and anti-matter masses, leading to a first violation of the most ... More
Achievements and Mirages in Uhecr and Neutrino AstronomyMay 11 2009Photon Astronomy ruled the last four centuries while wider photon band ruled last radio-X-Gamma century of discovery. Present decade may see the rise and competition of UHECR and UHE Neutrino Astronomy. Tau Neutrino may win and be the first flavor revealed. ... More
An apparent GRBs evolution around us or a sampling of thin GRB beaming jets?Oct 13 2009Oct 14 2009The gamma ray burst apparent average isotropic power versus their red-shift of all known GRB (Sept.2009) is reported. It calls for an unrealistic Gamma Ray Burst Evolution around us or it just probe the need of a very thin gamma precession-jet model. ... More
Neutrino oscillations along the Earth to probe flavor parameters: a NeuWorldJan 11 2013Mar 12 2013On 2010 MINOS experiment was showing an hint of possible different mass splitting and mixing angles for neutrinos and anti-neutrinos, suggesting a charge-parity-time (CPT) violation in the lepton sector; last year 2012 a second result from MINOS showed ... More
Beaming Selection and SN-GRB-Jets EvolutionFeb 19 2009After a decade of Fireball reign there is a hope for thin collimated Jet to solve the Supernova-GRB mystery
Anisotropies of Cosmic Rays and Search for Intergalactic Cascades from the direction of the Highest Energetic Cosmic Ray Events with the HEGRA Scintillator ArraySep 07 1999Data taken with the HEGRA Scintillator Array have been used to search for spatial anisotropies in the arrival directions of cosmic rays above 20 TeV. In this paper results on the search for TeV gamma-ray emission from the Galactic plane and the Gould ... More
Solid State Quantum BitsMay 27 2005We present the solid-state quantum circuits that have been developed in order to implement quantum bits suitable for a quantum processor. These qubits are either based on the quantum state of a single particle (semiconductor qubits), or on the quantum ... More
Applying MVC and PAC patterns in mobile applicationsJan 20 2010Additional requirements are set for mobile applications in relation to applications for desktop computers. These requirements primarily concern the support to different platforms on which such applications are performed, as well as the requirement for ... More
Bound States and Superconductivity in Dense Fermi SystemsDec 02 2008A quantum field theoretical approach to the thermodynamics of dense Fermi systems is developed for the description of the formation and dissolution of quantum condensates and bound states in dependence of temperature and density. As a model system we ... More
Gravity as an effective theoryOct 21 2009Using as inspiration the well known chiral effective lagrangian describing the interactions of pions at low energies, in these lectures we review the quantization procedure of Einstein gravity in the spirit of effective field theories. As has been emphasized ... More
Superconductivity in the 2D Hubbard model: Electron doping is differentAug 04 2008A variational Monte Carlo calculation is used for studying the ground state of the two-dimensional Hubbard model, including hopping between both nearest and next-nearest neighbor sites. Superconductivity with d-wave symmetry is found to be restricted ... More
Classical Functional Bethe Ansatz for $SL(N)$: separation of variables for the magnetic chainMar 04 1994The Functional Bethe Ansatz (FBA) proposed by Sklyanin is a method which gives separation variables for systems for which an $R$-matrix is known. Previously the FBA was only known for $SL(2)$ and $SL(3)$ (and associated) $R$-matrices. In this paper I ... More
A new class of magnetic materials: Sr2FeMoO6 and related compoundsFeb 27 2001Ordered double perovskite oxides of the general formula, A2BB'O6, have been known for several decades to have interesting electronic and magnetic properties. However, a recent report of a spectacular negative magnetoresistance effect in a specific member ... More
Perturbative BPS-algebras in superstring theoryFeb 27 1997This paper investigates the algebraic structure that exists on perturbative BPS-states in the superstring, compactified on the product of a circle and a Calabi-Yau fourfold. This structure was defined in a recent article by Harvey and Moore. It shown ... More
Existence, multiplicity and stability of endemic states for an age-structured S-I epidemic modelJun 20 2008Feb 25 2010We study an S--I type epidemic model in an age-structured population, with mortality due to the disease. A threshold quantity is found that controls the stability of the disease-free equilibrium and guarantees the existence of an endemic equilibrium. ... More
A locally symmetric Kaehler Einstein structure on the cotangent bundle of a space formAug 25 2003We obtain a locally symmetric Kaehler Einstein structure on the cotangent bundle of a Riemannian manifold of negative constant sectional curvature. Similar results are obtained on a tube around zero section in the cotangent bundle, in the case of a Riemannian ... More
Intrinsic Properties of the <z>=2.7 Lyman Alpha Forest from Keck Spectra of QSO HS 1946+7658Jan 27 1997Feb 20 1997We present the highest quality Lyman Alpha forest spectra published to date, from the QSO HS 1946+7658. The distribution of H I column densities is a power law of slope -1.5 from Log N = 12.1 - 14. This power law can extend to N = 0, because lines weaker ... More
Possible flakes of molecular hydrogen in the early UniverseNov 18 2002The thermochemistry of H2 and HD in non-collapsed, non-reionized primordial gas up to the end of the dark age is investigated with recent radiation-matter and chemical reaction rates taking into account the efficient coolant HD, and the possibility of ... More
The category of singularities as a crystal and global Springer fibersDec 14 2014May 12 2015We prove the "Gluing Conjecture" on the spectral side of the categorical geometric Langlands correspondence. The key tool is the structure of crystal on the category of singularities, which allows to reduce the conjecture to the question of homological ... More
The spin-1 ladder : A bosonization studyAug 16 1999We construct a field-theoretic description of two coupled spin-1 Heisenberg chains, starting with the known representation of a single spin-1 chain in terms of Majorana fermions (or Ising models). After reexamining the bosonization rules for two Ising ... More
Ginzburg-Landau equations for superconducting quark matter in neutron starsJun 19 2000May 18 2002We investigate magnetic properties of color superconducting quark matter within a Ginzburg-Landau approach. The simultaneous coupling of the quark fields to gluonic and electromagnetic gauge fields leads to rotated electromagnetism with a massive (Higgsed) ... More
13CO(1-0) and 12CO(2-1) in the center of the barred galaxy NGC 1530Apr 26 1999We present 13CO(1-0) and 12CO(2-1) aperture synthesis maps of the barred spiral galaxy NGC1530. The angular resolutions are respectively 3''.1 and 1''.6. Both transitions show features similar to the 12CO(1-0) map, with a nuclear feature (a ring or unresolved ... More
French Roadmap for complex Systems 2008-2009Jul 13 2009This second issue of the French Complex Systems Roadmap is the outcome of the Entretiens de Cargese 2008, an interdisciplinary brainstorming session organized over one week in 2008, jointly by RNSC, ISC-PIF and IXXI. It capitalizes on the first roadmap ... More
Quantitative determination of the level of cooperation in the presence of punishment in three public good experimentsOct 25 2006Nov 21 2007Strong reciprocity is a fundamental human characteristic associated with our extraordinary sociality and cooperation. Laboratory experiments on social dilemma games and many field studies have quantified well-defined levels of cooperation and propensity ... More
Representations of algebraic groups over a 2-dimensional local fieldFeb 14 2003Jun 14 2004We introduce a categorical framework for the study of representations of $G_F$, where $G$ is a reductive group, and $\bF$ is a 2-dimensional local field, i.e. $F=K((t))$, where $K$ is a local field. Our main result says that the space of functions on ... More
Hecke operators on quasimaps into horospherical varietiesNov 11 2004Nov 10 2006Let $G$ be a connected reductive complex algebraic group. This paper is part of a project devoted to the space $Z$ of meromorphic quasimaps from a curve into an affine spherical $G$-variety $X$. The space $Z$ may be thought of as an algebraic model for ... More
Controlled dynamics of qubits in the presence of decoherenceJun 19 2007An exactly solvable model for the decoherence of one and two-qubit states interacting with a spin-bath, in the presence of a time-dependent magnetic field is studied. The magnetic field is static along $\hat{z}$ direction and oscillatory in the transverse ... More
Superconductivity and antiferromagnetism in the two-dimensional Hubbard model: a variational studyAug 21 2007A variational ground state of the repulsive Hubbard model on a square lattice is investigated numerically for an intermediate coupling strength (U = 8t) and for moderate sizes (from 6 x 6 to 10 x 10). Our ansatz is clearly superior to other widely used ... More
Relaxation measurements in the regime of the second magnetization peak in Nb filmsNov 05 2004We report on magnetic measurements as a function of field, temperature and time (relaxation) in superconducting Nb films of critical temperature Tc = 9.25 K. The magnetic measurements as a function of field exhibited a second magnetization peak (SMP) ... More
Microscopic description of pair transfer between two superfluid systems (II): a quantum mixing of Time-Dependent Hartree-Fock Bogolyubov trajectoriesFeb 18 2019While superfluidity is accurately grasped with a state that explicitly breaks the particle number symmetry, a precise description of phenomena like the particle transfer during heavy-ion reactions can only be achieved by considering systems with good ... More
Hadronic resonances, strange and multi-strange particle production in Xe-Xe and Pb-Pb collisions with ALICE at the LHCJul 23 2018We present measurements of hadronic resonance, strange and multi-strange particle production in collisions of Xe-Xe and Pb-Pb at the center-of-mass energies of $\sqrt{s_{NN}}=5.44$ and $5.02$ TeV, respectively, by the ALICE collaboration at the LHC. Particle ... More
Morphological Annotations for Groups in the FIRST DatabaseApr 19 2011The morphology of selected groups of sources in the FIRST (Faint Images of the Radio Sky at Twenty Centimeters) survey and catalog is examined. Sources in the FIRST catalog (April 2003 release, 811117 entries) were sorted into singles, doubles, triples ... More
On the Representations of Leavitt path algebrasJun 14 2010Oct 08 2013Given a graph E we define E-algebraic branching systems, show their existence and how they induce representations of the associated Leavitt path algebra. We also give sufficient conditions to guarantee faithfulness of the representations associated to ... More
Substitution Dynamical Systems: Characterization of Linear Repetitivity and ApplicationsFeb 19 2003Oct 10 2003We consider dynamical systems arising from substitutions over a finite alphabet. We prove that such a system is linearly repetitive if and only if it is minimal. Based on this characterization we extend various results from primitive substitutions to ... More
A class of locally symmetric Kaehler Einstein structures on the nonzero cotangent bundle of a space formJul 21 2004We obtain a class of locally symetric Kaehler Einstein structures on the nonzero cotangent bundle of a Riemannian manifold of positive constant sectional curvature. The obtained class of Kaehler Einstein structures depends on one essential parameter and ... More
A Kaehler Einstein structure on the nonzero cotangent bundle of a space formMay 07 2004We obtain a Kaehler Einstein structure on the nonzero cotangent bundle of a Riemannian manifold of positive constant sectional curvature. The obtained Kaehler Einstein structure cannot have constant holomorphic sectional curvature and is not locally symmetric. ... More
Semi-classical description of the frustrated antiferromagnetic chainSep 21 1994The antiferromagnetic Heisenberg model on a chain with nearest and next nearest neighbor couplings is mapped onto the $SO(3)$ nonlinear sigma model in the continuum limit. In one spatial dimension this model is always in its disordered phase and a gap ... More
GSC 2314-0530: the shortest-period eclipsing system with dMe componentsMay 03 2010CCD photometric observations in VRI colors and spectroscopic observations of the newly discovered eclipsing binary GSC 2314-0530 (NSVS 6550671) with dMe components and very short period of P=0.192636 days are presented. The simultaneous light-curve solution ... More
Non-existence of a dilaton gravity action for the exact string black holeOct 07 2002Nov 07 2002We prove that no local diffeomorphism invariant two-dimensional theory of the metric and the dilaton without higher derivatives can describe the exact string black hole solution found a decade ago by Dijkgraaf, Verlinde and Verlinde. One of the key points ... More
eta and eta' mesons and dimension 2 gluon condensate <A^2>Dec 05 2005The study of light pseudoscalar quark-antiquark bound states in the Dyson-Schwinger approach with the effective QCD coupling enhanced by the interplay of the dimension 2 gluon condensate <A^2> and dimension 4 gluon condensate <F^2>, is extended to the ... More
Supersymmetric AdS(4) compactifications of IIA supergravityDec 21 2004Jan 25 2005We derive necessary and sufficient conditions for N=1 compactifications of (massive) IIA supergravity to AdS(4) in the language of SU(3) structures. We find new solutions characterized by constant dilaton and nonzero fluxes for all form fields. All fluxes ... More
A Selection of Giant Radio Sources from NVSSMar 22 2016May 10 2016Results of the application of pattern recognition techniques to the problem of identifying Giant Radio Sources (GRS) from the data in the NVSS catalog are presented and issues affecting the process are explored. Decision-tree pattern recognition software ... More
Topological Dependence of Universal Correlations in Multi-Parameter HamiltoniansDec 03 1996Universality of correlation functions obtained in parametric random matrix theory is explored in a multi-parameter formalism, through the introduction of a diffusion matrix $D_{ij}(R)$, and compared to results from a multi-parameter chaotic model. We ... More
Comparing Pattern Recognition Feature Sets for Sorting Triples in the FIRST DatabaseMay 03 2006Pattern recognition techniques have been used with increasing success for coping with the tremendous amounts of data being generated by automated surveys. Usually this process involves construction of training sets, the typical examples of data with known ... More
A class of locally symmetric Kaehler Einstein structures on the cotangent bundle of a space formJul 14 2004We obtain a class of locally symmetric Kaehler Einstein structures on the cotangent bundle of a Riemannian manifold of negative sectional curvature. Similar results are obtained in the case of a Riemannian manifold of positive sectional curvature. The ... More
Deformation effects on the coexistence between neutron-proton and particle like pairing in N=Z medium mass nucleiNov 07 2014A model combining self-consistent mean-field and shell-model techniques is used to study the competition between particle like and proton-neutron pairing correlations in fp-shell even-even self-conjugate nuclei. Results obtained using constant two-body ... More
The accretion-diffusion scenario for metals in cool white dwarfsMar 08 2006We calculated diffusion timescales for Ca, Mg, Fe in hydrogen atmosphere white dwarfs with temperatures between 5000 and 25000 K. With these timescales we determined accretion rates for a sample of 38 DAZ white dwarfs from the recent studies of Zuckerman ... More
Spherical varieties and Langlands dualityNov 10 2006Aug 07 2007Let G be a connected reductive complex algebraic group. This paper is devoted to the space Z of meromorphic quasimaps from a curve into an affine spherical G-variety X. The space Z may be thought of as an algebraic model for the loop space of X. In this ... More
Chemical evolution of turbulent protoplanetary disks and the Solar nebulaApr 21 2011Aug 23 2011This is the second paper in a series where we study the influence of transport processes on the chemical evolution of protoplanetary disks. Our analysis is based on a flared alpha-model of the DM Tau system, coupled to a large gas-grain chemical network. ... More
The elliptic genus of Calabi-Yau 3- and 4-folds, product formulae and generalized Kac-Moody algebrasJul 03 1996In this paper the elliptic genus for a general Calabi-Yau fourfold is derived. The recent work of Kawai calculating N=2 heterotic string one-loop threshold corrections with a Wilson line turned on is extended to a similar computation where K3 is replaced ... More
Uniform Kazhdan groupsJun 01 2006We construct first examples of infinite groups having property (T) whose Kazhdan constants admit a lower bound independent of the choice of a finite generating set.
A locally symmetric Kaehler Einstein structure on a tube in the nonzero cotangent bundle of a space formAug 29 2003We obtain a locally symmetric Kaehler Einstein structure on a tube in the nonzero cotangent bundle of a Riemannian manifold of positive constant sectional curvature. The obtained Kaehler Einstein structure cannot have constant holomorphic sectional curvature. ... More