Results for "J. Buhot"

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A Tale of Two Metals: contrasting criticalities in the pnictides and hole-doped cupratesMay 10 2018The iron-based high temperature superconductors share a number of similarities with their copper-based counterparts, such as reduced dimensionality, proximity to states of competing order, and a critical role for 3d electron orbitals. Their respective ... More
Finite size scaling of the bayesian perceptronMar 20 1997We study numerically the properties of the bayesian perceptron through a gradient descent on the optimal cost function. The theoretical distribution of stabilities is deduced. It predicts that the optimal generalizer lies close to the boundary of the ... More
Symmetry of the Excitations in the Hidden Order State of URu2Si2Jul 17 2014Nov 05 2014We have performed polarized electronic Raman scattering on URu2Si2 single crystals at low temperature down to 8 K in the hidden order state and under magnetic field up to 10 T. The hidden order state is characterized by a sharp excitation at 1.7 meV and ... More
Switching of the magnetic order in CeRhIn$_{5-x}$Sn$_{x}$ in the vicinity of its quantum critical pointJun 03 2014We report neutron diffraction experiments performed in the tetragonal antiferromagnetic heavy fermion system CeRhIn$_{5-x}$Sn$_{x}$ in its ($x$, $T$) phase diagram up to the vicinity of the critical concentration $x_c$ $\approx$ 0.40, where long range ... More
Optical conductivity of URu$_2$Si$_2$ in the Kondo Liquid and Hidden-Order PhasesJul 16 2015We measured the polarized optical conductivity of URu$_2$Si$_2$ from room temperature down to 5 K, covering the Kondo state, the coherent Kondo liquid regime, and the hidden-order phase. The normal state is characterized by an anisotropic behavior between ... More
Fluctuation-dissipation relations in the activated regime of simple strong-glass modelsNov 02 2001May 22 2002We study the out-of-equilibrium fluctuation-dissipation (FD) relations in the low temperature, finite time, physical aging regime of two simple models with strong glass behaviour, the Fredrickson-Andersen model and the square-plaquette interaction model. ... More
Storage Capacity of the Tilinglike Learning AlgorithmAug 10 2000The storage capacity of an incremental learning algorithm for the parity machine, the Tilinglike Learning Algorithm, is analytically determined in the limit of a large number of hidden perceptrons. Different learning rules for the simple perceptron are ... More
Phase transitions in optimal unsupervised learningSep 25 1997Nov 12 1997We determine the optimal performance of learning the orientation of the symmetry axis of a set of P = alpha N points that are uniformly distributed in all the directions but one on the N-dimensional sphere. The components along the symmetry breaking direction, ... More
Crossover from Fragile to Strong Glassy Behaviour in Kinetically Constrained SystemsApr 18 2001We show the existence of fragile-to-strong transitions in kinetically constrained systems by studying the equilibrium and out-of-equilibrium dynamics of a generic constrained Ising spin chain which interpolates between the symmetric and fully asymmetric ... More
Storage capacity of a constructive learning algorithmSep 16 1999Upper and lower bounds for the typical storage capacity of a constructive algorithm, the Tilinglike Learning Algorithm for the Parity Machine [M. Biehl and M. Opper, Phys. Rev. A {\bf 44} 6888 (1991)], are determined in the asymptotic limit of large training ... More
Learning properties of Support Vector MachinesFeb 17 1998We study the typical learning properties of the recently proposed Support Vectors Machines. The generalization error on linearly separable tasks, the capacity, the typical number of Support Vectors, the margin, and the robustness or noise tolerance of ... More
Coexistence of orbital and quantum critical magnetoresistance in FeSe$_{1-x}$S$_{x}$Mar 13 2019The recent discovery of a non-magnetic nematic quantum critical point (QCP) in the iron chalcogenide family FeSe$_{1-x}$S$_{x}$ has raised the prospect of investigating, in isolation, the role of nematicity on the electronic properties of correlated metals. ... More
Driving spin excitations by hydrostatic pressure in BiFeO3Sep 01 2015Optical spectroscopy has been combined with computational and theoretical techniques to show how the spin dynamics in the model multiferroic BiFeO3 responds to the application of hydrostatic pressure and its corresponding series of structural phase transitions ... More
Polymers translocation through nano-pores in vibrating thin membranesJun 14 2016Jun 15 2016Polymer translocation is a promising strategy for the next-generation DNA sequencing technologies. The use of biological and synthetic nano-pores, however, still suffers from serious drawbacks. In particular, the width of the membrane layer can accommodate ... More
Simple strong glass forming models: mean-field solution with activationSep 16 2002We introduce simple models, inspired by previous models for froths and covalent glasses, with trivial equilibrium properties but dynamical behaviour characteristic of strong glass forming systems. These models are also a generalization of backgammon or ... More
Lattice dynamics of the heavy fermion compound URu$_2$Si$_2$Oct 12 2014We report a comprehensive investigation of the lattice dynamics of URu$_2$Si$_2$ as a function of temperature using Raman scattering, optical conductivity and inelastic neutron scattering measurements as well as theoretical {\it ab initio} calculations. ... More
Glassy behaviour in a 3-state spin modelJan 08 2001Apr 10 2001In this article we study a simple spin model which has a non-interacting Hamiltonian but constrained dynamics. The model, which is a simplification of a purely toplogical cellular model, displays glassy behaviour, involves activated processes and exhibits ... More
Rigorous Bounds to Retarded LearningJan 15 2002We show that the lower bound to the critical fraction of data needed to infer (learn) the orientation of the anisotropy axis of a probability distribution, determined by Herschkowitz and Opper [Phys.Rev.Lett. 86, 2174 (2001)], is not always valid. If ... More
Antiferromagnetism and Superconductivity in CeRhIn$_5$Apr 19 2011We discuss recent results on the heavy fermion superconductor CeRhIn$_5$ which presents ideal conditions to study the strong coupling between the suppression of antiferromagnetic order and the appearance of unconventional superconductivity. The appearance ... More
Stability of spherical stellar systems I : Analytical resultsNov 22 1995The so-called ``symplectic method'' is used for studying the linear stability of a self-gravitating collisionless stellar system, in which the particles are also submitted to an external potential. The system is steady and spherically symmetric, and its ... More
Center Disorder in the 3D Georgi-Glashow ModelApr 15 1998We present a number of arguments relating magnetic disorder to center disorder, in pure Yang-Mills theory in D=3 and D=4 dimensions. In the case of the D=3 Georgi-Glashow model, we point out that the abelian field distribution is not adequatedly represented, ... More
The Impact of Galaxy Formation on the Diffuse Background RadiationOct 23 2000The far infrared background is a sink for the hidden aspects of galaxy formation. At optical wavelengths, ellipticals and spheroids are old, even at $z \sim 1.$ Neither the luminous formation phase nor their early evolution is seen in the visible. We ... More
Recoil Polarization for Delta Excitation in Pion ElectroproductionMay 23 2005We measured angular distributions of recoil-polarization response functions for neutral pion electroproduction for W=1.23 GeV at Q^2=1.0 (GeV/c)^2, obtaining 14 separated response functions plus 2 Rosenbluth combinations; of these, 12 have been observed ... More
Spinons and helimagnons in the frustrated Heisenberg chainFeb 23 2012We investigate the dynamical spin structure factor S(q,w) for the Heisenberg chain with ferromagnetic nearest (J1<0) and antiferromagnetic next-nearest (J2>0) neighbor exchange using bosonization and a time-dependent density-matrix renormalization group ... More
Non-adiabatic primordial fluctuationsNov 10 2009Apr 19 2010We consider general mixtures of isocurvature and adiabatic cosmological perturbations. With a minimal assumption set consisting of the linearized Einstein equations and a primordial perfect fluid we derive the second-order action and its curvature variables. ... More
Nuclear time-reversal violation and the Schiff moment of 225RaMar 22 2005May 12 2005We present a comprehensive mean-field calculation of the Schiff moment of the nucleus 225Ra, the quantity which determines the static electric dipole moment of the corresponding atom if time-reversal (T) invariance is violated in the nucleus. The calculation ... More
Solution of the Skyrme-Hartree-Fock equations in the Cartesian deformed harmonic-oscillator basis. (III) HFODD (v1.75r): a new version of the programMar 01 2000We describe the new version (v1.75r) of the code HFODD which solves the nuclear Skyrme-Hartree-Fock problem by using the Cartesian deformed harmonic-oscillator basis. Three minor errors that went undetected in the previous version have been corrected. ... More
On Zero-Mass Ground States in Super-Membrane Matrix ModelsJan 23 1997We recall a formulation of super-membrane theory in terms of certain matrix models. These models are known to have a mass spectrum given by the positive half-axis. We show that, for the simplest such matrix model, a normalizable zero-mass ground state ... More
Measurement of CP violation at a Neutrino FactoryMay 29 2001The prospects of measuring CP violation in the leptonic sector using the intense neutrino beams arising from muon decay in the straight sections of a muon accumulator ring (the so-called neutrino factory) are discussed.
Thermalization of Quantum Fields from Time-Reversal Invariant Evolution EquationsJun 14 2000We study the time evolution of correlation functions in closed quantum systems for nonequilibrium ensembles of initial conditions. For a scalar quantum field theory we show that generic time-reversal invariant evolutions approach equilibrium at large ... More
Permutation Group Symmetry and CorrelationsJun 11 2013Correlation factors are constructed that are consistent with the permutation symmetry group of N Fermions at given value of the filling factor.
Horizontal symmetry in the algebraic approach of genetic codeFeb 14 2013Using concepts of physics of elementary particles concerning the breaking of symmetry and grannd unified theory we propose to study with the algebraic approximation the degeneracy finded in the genetic code with the incorporation of a horizontal symmetry ... More
The winds of the hot massive first starsSep 07 2005We study dynamical aspects of circumstellar environment around massive zero-metallicity first stars. For this purpose we apply our NLTE wind models. We show that the hydrogen-helium stellar wind from stationary massive first generation (Population III) ... More
Inverted crossover resonance aiding laser cooling of $^{171}$YbMar 03 2016Apr 19 2016We observe an inverted crossover resonance in $\pi$-driven four-level systems, where $F'-F=0,+1$. The signal is observed through saturated absorption spectroscopy of the $(6s^{2})$ $^{1}S_{0}$ $-$ $(6s6p)$ $^{3}P_{1}$ transition in $^{171}$Yb, where the ... More
Hartree shift in unitary Fermi gasesMar 24 2011The Hartree energy shift is calculated for a unitary Fermi gas. By including the momentum dependence of the scattering amplitude explicitly, the Hartree energy shift remains finite even at unitarity. Extending the theory also for spin-imbalanced systems ... More
Coulomb blockade in electron transport through a C$_{60}$ molecule from first principlesMay 23 2005We present results of spin-unrestricted first-principles quantum transport for a gated C$_{60}$ molecule weakly contacted to Al electrodes, making emphasis on the role played by the electronic localization and the spin degree of freedom. As expected, ... More
Nuclear suppression of dileptons at forward rapiditiesDec 14 2010Data from E772 and E866 experiments on the Drell-Yan process exhibit a significant nuclear suppression at large Feynman xF. We show that a corresponding kinematic region does not allow to interpret this as a manifestation of coherence or a Color Glass ... More
Asymmetric Wolf-Rayet winds: implications for GRB afterglowsJan 25 2007Recent observations of Wolf-Rayet (WR) binaries WR151 and WR155 infer that their stellar winds are asymmetric. We show that such asymmetries can alter the stellar-wind bubble structure, bringing the wind-termination shock closer to the WR star. If the ... More
Unbiased estimators in Quantum Monte Carlo methods: application to liquid $^4$HeJan 18 1995A Monte Carlo algorithm for computing quantum mechanical expectation values of coordinate operators in many body problems is presented. The algorithm, that relies on the forward walking method, fits naturally in a Green's Function Monte Carlo calculation, ... More
Asymptotic cones and Assouad-Nagata dimensionOct 10 2006Oct 20 2006We prove the dimension of any asymptotic cone over a metric space X does not exceed the asymptotic Assouad-Nagata dimension of X. This improves a result of Dranishnikov and Smith who showed that dim(Y) does not exceed asymptotic Assouad-Nagata dimension ... More
A Plasma Instability Theory of Gamma-Ray Burst EmissionApr 02 1999A new theory for gamma-ray burst radiation is presented. In this theory, magnetic fields and relativistic electrons are created through plasma processes arising as a relativistic shell passes through the interstellar medium. The gamma-rays are produced ... More
Pi^0_1 ordinal analysis beyond first order arithmeticDec 11 2012In this paper we give an overview of an essential part of a Pi^0_1 ordinal analysis of Peano Arithmetic (PA) as presented by Beklemishev. This analysis is mainly performed within the polymodal provability logic GLP. We reflect on ways of extending this ... More
Fazendo 3D com uma camera soDec 14 2010Jan 29 2012A simple system to make stereo photography or videos based in just two mirrors was made in 1989 and recently adapted to a digital camera setup.
Enlarging Holograms Under White Light, a Way to Save Holographic MaterialMay 08 2009We developed techniques for employing holographic screens under white light, first exhibited to the public in 1989 (3) (4) which demonstrated the possibility of enlarging holograms already in 1990 (5). Fig. 1 shows how we encode views in a first step. ... More
White Light Colour Photography for Rendering Holoimages in a Diffractive ScreenApr 16 2009The capability of color encoding the continuous sequence of views from a scene was demonstrated previously by the author (1990). In the present work, the scheme for this process is shown where white light from a black and white object is diffracted at ... More
On the quality of the Olmec mirrors and its utilizationJan 29 2007Archaeological mirrors from the Olmec civilization were analyzed in the context of bibliography produced in the last two decades. Photographs of its images are showed as a proof of its good quality. Some suggestions are made on its probable utilization. ... More
Lagrangian and Hamiltonian for the Bondi-Sachs metricsMar 31 2004Feb 03 2015We calculate the Hilbert action for the Bondi-Sachs metrics. It yields the Einstein vacuum equations in a closed form. Following the Dirac approach to constrained systems we investigate the related Hamiltonian formulation.
Quartz Tuning Forks and Acoustic Phenomena - Application to Superfluid HeliumApr 09 2013Jan 30 2016Immersed mechanical resonators are well suited for probing the properties of fluids, since the surrounding environment influences the resonant characteristics of such oscillators in several ways. Quartz tuning forks have gained much popularity in recent ... More
Curvettes and clusters of infinitely near pointsMar 30 2009Jul 03 2011The aim of this paper is to revise the theory of clusters of infinitely near points for arbitrary fields. We describe in particular the intersection matrix of such a cluster, we introduce the notion of curvette over an arbitrary field and we relate it ... More
Phase transitions in systems of magnetic dipoles on a square lattice with quenched disorderSep 14 2008We study by Monte Carlo simulations the effect of quenched orientational disorder in systems of interacting classical dipoles on a square lattice. Each dipole can lie along any of two perpendicular axes that form an angle psi with the principal axes of ... More
Effective realization of random magnetic fields in compounds with large single-ion anisotropyJun 20 2016We show that spin $S=1$ system with large and random single-ion anisotropy can be at low energies mapped to a $S=1/2$ system with random magnetic fields. This is for example realized in Ni(Cl$_{1-x}$Br$_{x}$)$_2$-4SC(NH$_2$)$_2$ compound (DTNX) and therefore ... More
Building a linguistic corpus from bee dance dataJun 28 2004This paper discusses the problems and possibility of collecting bee dance data in a linguistic \textit{corpus} and use linguistic instruments such as Zipf's law and entropy statistics to decide on the question whether the dance carries information of ... More
Application of Jitter Radiation: Gamma-ray Burst Prompt PolarizationSep 20 2013A high-degree of polarization of gamma-ray burst (GRB) prompt emission has been confirmed in recent years. In this paper, we apply jitter radiation to study the polarization feature of GRB prompt emission. In our framework, relativistic electrons are ... More
An addendum to `A rigidity property for the set of all characters induced by valuations'May 28 2013This corrects and amplifies some comments made in a paper by Robert Bieri and the author with the above title.
Equivalence between the Morita categories of etale Lie groupoids and of locally grouplike Hopf algebroidsMar 13 2007Any etale Lie groupoid G is completely determined by its associated convolution algebra C_c(G) equipped with the natural Hopf algebroid structure. We extend this result to the generalized morphisms between etale Lie groupoids: we show that any principal ... More
Superlogarithmic estimates on pseudoconvex domains and CR manifoldsOct 15 2004This paper is concerned with proving superlogarithmic estimates for the operator $\Box_b$ on pseudoconvex CR manifolds and using them to establish hypoellipticity of $\Box_b$ and of the $\bar{\partial}$-Neumann problem. These estimates are established ... More
A characterization of Sobolev spaces on the sphere and an extension of Stolarsky's invariance principle to arbitrary smoothnessMar 23 2012In this paper we study reproducing kernel Hilbert spaces of arbitrary smoothness on the sphere $\mathbb{S}^d \subset \mathbb{R}^{d+1}$. The reproducing kernel is given by an integral representation using the truncated power function $(\boldsymbol{x} \cdot ... More
A note on Positivity of the CM line bundleMay 11 2006Aug 09 2006We show that positivity of the CM line associated to a family of polarised varieties is intimately related to the stability of its members. We prove that the CM line is nef on any curve which meets the stable locus, and that it is pseudoeffective (i.e. ... More
Social Balance and the Bernoulli EquationJan 14 2017Dec 13 2017Since the 1940's there has been an interest in the question why social networks often give rise to two antagonistic factions. Recently a dynamical model of how and why such a balance might occur was developed. This note provides an introduction to the ... More
Chaplygin's sphereSep 01 2004Chaplygin proved the integrability by quadratures of a round sphere, rolling without slipping on a horizontal plane, with center of mass at the center of the sphere, but with arbitrary moments of inertia. Although the system is integrable in every sense ... More
Vortex matter in mesoscopic superconductorsSep 03 1998Superconducting mesoscopic devices in magnetic fields present novel properties which can only be accounted for by both the quantum confinement of the Cooper pairs and by the interaction between the magnetic-field-induced vortices. Sub-micrometer disks, ... More
Microscopic calculation of the phonon-roton branch in superfluid $^4$HeJul 29 1996Diffusion Monte Carlo results for the phonon-roton excitation branch in bulk liquid $^4$He at zero temperature are presented. The sign problem associated to the excited wave function has been dealt both with the fixed-node approximation and the released-node ... More
Self-consistent Skyrme QRPA for use in axially-symmetric nuclei of arbitrary massMay 31 2010We describe a new implementation of the quasiparticle random phase approximation (QRPA) in axially-symmetric deformed nuclei with Skyrme and volume-pairing energy-density functionals. After using a variety of tests to demonstrate the accuracy of the code ... More
Direct Photon Production in Proton-Nucleus and Nucleus-Nucleus CollisionsJun 01 2011Prompt photons produced in a hard reaction are not accompanied with any final state interaction, either energy loss or absorption. Therefore, besides the Cronin enhancement at medium transverse momenta pT and small isotopic corrections at larger pT, one ... More
Globally controlled fault tolerant quantum computationJul 08 2007We describe a method to execute globally controlled quantum information processing which admits a fault tolerant quantum error correction scheme. Our scheme nominally uses three species of addressable two-level systems which are arranged in a one dimensional ... More
Superballistic Diffusion of Entanglement in Disordered Spin ChainsJun 06 2005Sep 12 2005We study the dynamics of a single excitation in an infinite XXZ spin chain, which is launched from the origin. We study the time evolution of the spread of entanglement in the spin chain and obtain an expression for the second order spatial moment of ... More
Strangeness and Quark Gluon PlasmaMay 25 2003A brief summary of strangeness mile stones is followed by a chemical non-equilibrium statistical hadronization analysis of strangeness results at SPS and RHIC. Strange particle production in AA interactions at \sqrt{s_{NN}}\ge 8.6 GeV can be understood ... More
Breakdown of step-flow growth in unstable homoepitaxyJan 13 2004Two mechanisms for the breakdown of step flow growth, in the sense of the appearance of steps of opposite sign to the original vicinality, are studied by kinetic Monte Carlo simulations and scaling arguments. The first mechanism is the nucleation of islands ... More
What does the CCFR measurement of the Gross--Llewelyn Smith sum rule tell us?Oct 14 1994Oct 18 1994Recently the CCFR Collaboration reported the measurement of the Gross--Llewellyn Smith sum rule %at $Q^2=3\; \mr{GeV}^2$: $\int^{1}_{0}\mr{d}F_{3}^{\nu p+\bare{\nu}p}(x,Q^2=3\;\mr{GeV}^2)= 2.50\pm 0.018(\mr{stat})$. Subsequently Kataev and Sidorov analyzed ... More
Parton-Hadron duality in event generatorsAug 28 1992Sep 04 1992The validity of local parton-hadron duality within the framework of HERWIG and JETSET event generators is investigated. We concentrate on ${\rm e}^{+}{\rm e}^{-}$ annihilations in LEP 2 energy range as these interactions provide theoretically the cleanest ... More
Accretion by GalaxiesMar 14 2000Both theory and observation indicate that galaxies like the Milky Way accrete matter at the rate of a few Msun per year.
Complexity fits the fittestDec 11 2012In this paper we shall relate computational complexity to the principle of natural selection. We shall do this by giving a philosophical account of complexity versus universality. It seems sustainable to equate universal systems to complex systems or ... More
Quantum field effects in coupled atomic and molecular Bose-Einstein condensatesJun 21 2001This paper examines the parameter regimes in which coupled atomic and molecular Bose-Einstein condensates do not obey the Gross-Pitaevskii equation. Stochastic field equations for coupled atomic and molecular condensates are derived using the functional ... More
Interaction of antiprotons with nucleiOct 26 2015We performed fully self-consistent calculations of $\bar{p}$-nuclear bound states using a complex ${\bar p}$-nucleus potential accounting for $\bar{p}$-atom data. While the real part of the potential is constructed within the relativistic mean-field (RMF) ... More
Stability of the lattice formed in first-order phase transitions to matter containing strangeness in protoneutron starsApr 18 2002Well into the deleptonization phase of a core collapse supernova, a first-order phase transition to matter with macroscopic strangeness content is assumed to occur and lead to a structured lattice defined by negatively charged strange droplets. The lattice ... More
Composite resonances and their impact on the EW chiral LagrangianNov 12 2015In this talk we study the low-energy effective couplings generated by strongly-coupled electroweak models that contain heavy composite resonances. Invariance under $SU(2)_L\times SU(2)_R$ is a key ingredient in the construction of the resonance action. ... More
Hausdorff dimension of boundaries of self-affine tiles in R^nJan 15 1997We present a new method to calculate the Hausdorff dimension of a certain class of fractals: boundaries of self-affine tiles. Among the interesting aspects are that even if the affine contraction underlying the iterated function system is not conjugated ... More
A Noncommutative Extension of GravityJul 22 1993The commutative algebra of functions on a manifold is extended to a noncommutative algebra by considering its tensor product with the algebra of nxn complex matrices. Noncommutative geometry is used to formulate an extension of the Einstein-Hilbert action. ... More
Noncommutative Kaluza-Klein TheoryJan 31 1996Efforts have been made recently to reformulate traditional Kaluza-Klein theory by using a generalized definition of a higher-dimensional extended space-time. Both electromagnetism and gravity have been studied in this context. We review some of the models ... More
The periodic b-equation and Euler equations on the circleJan 18 2010In this note we show that the periodic b-equation can only be realized as an Euler equation on the Lie group Diff(S^1) of all smooth and orientiation preserving diffeomorphisms on the cirlce if b=2, i.e. for the Camassa-Holm equation. In this case the ... More
A new proof of the Mullineux conjectureOct 07 2002Let S_d be the symmetric group on d letters and let k be a field of characteristic p>2. Tensoring an irreducible S_d module with the sign representation defines an involution on the p-regular partitions of d. It is suprisingly difficult to describe this ... More
Structure of pulsar beams: conal versus patchyAug 14 2002Structure of mean pulsar radiation patterns is discussed within the nested-cones and patchy beam models. Observational predictions of both these models are analyzed and compared with available data on pulsar waveforms. It is argued that observational ... More
Monte Carlo Analysis of a New Interatomic Potential for HeSep 14 1993By means of a Quadratic Diffusion Monte Carlo method we have performed a comparative analysis between the Aziz potential and a revised version of it. The results demonstrate that the new potential produces a better description of the equation of state ... More
On a Question of Glasby, Praeger, and XiaFeb 26 2014Recently, Glasby, Praeger, and Xia asked for necessary and sufficient conditions for the `Jordan Partition' $\lambda(r,s,p)$ to be standard. We give such conditions when $p$ is an odd prime.
Weedy adaptation in Setaria spp.: IX. Effects of salinity, temperature, light and seed dormancy on Setaria faberi seed germinationAug 26 2014Life in salty habitats is a function of tolerance to those chemicals at all critical phases of a plant's life history. The ability to withstand salt as an established plant may require different mechanisms and plant traits than those needed to germinate ... More
Gamma-ray Burst Prompt Emission: Jitter Radiation in Stochastic Magnetic Field RevisitedMar 12 2011We revisit the radiation mechanism of relativistic electrons in the stochastic magnetic field and apply it to the high-energy emissions of gamma-ray bursts (GRBs). We confirm that jitter radiation is a possible explanation for GRB prompt emission in the ... More
Measuring CMB polarisation with the Planck HFIDec 19 2001We describe the Planck HFI design and expected performances for measuring CMB polarisation.
Polarization of high-energy pulsar radiation in the striped wind modelMay 20 2005The Stokes parameters of the pulsed synchrotron radiation produced in the striped pulsar wind model are computed and compared with optical observations of the Crab pulsar. We assume the main contribution to the wind emissivity comes from a thin transition ... More
Photoproduction at HERANov 21 2003Dec 03 2003Selected aspects of photoproduction in ep scattering at the HERA collider, studied with the ZEUS detector, are presented. The results are interpreted in the formalism of Vector Dominance Model, Regge theory and perturbative Quantum Chromodynamics.
χ-Systems for Correlation FunctionsAug 22 2012Sep 24 2012We consider the strong coupling limit of 4-point functions of heavy operators in N=4 SYM dual to strings with no spin in AdS. We restrict our discussion for operators inserted on a line. The string computation factorizes into a state-dependent sphere ... More
Information channel capacity in the field theory estimationDec 26 2012The construction of the information capacity for the vector position parameter in the Minkowskian space-time is presented. This lays the statistical foundations of the kinematical term of the Lagrangian of the physical action for many field theory models, ... More
Can stellar wobble in triple systems mimic a planet?Sep 13 2005The first extrasolar planets have been detected by the measurement of the wobble of the parent star. This wobble leads to the periodic modulation of three observables: the radial velocity, the position on the sky and the time of arrival of periodic signals. ... More
A Cartier-Gabriel-Kostant structure theorem for Hopf algebroidsDec 29 2010In this paper we give an extension of the Cartier-Gabriel-Kostant structure theorem to Hopf algebroids.
Optimizing wide-field coded aperture imaging: radial mask holes and scanningOct 16 2003Imaging at hard X-ray energies (~10-600 keV) over very large fields of view (~60 deg per telescope) is required to conduct a high sensitivity all-sky and all-time survey for black holes. The proposed Energetic X-ray Imaging Survey Telescope (EXIST) could ... More
The 3-D composition of the Galactic interstellar medium. The hot phases and X-ray absorbing materialNov 19 2002We present maps of the Galactic X-ray Halo and constrain the location of X-ray absorbing gas using the X-ray radiation transfer as distance a indicator. Based on a consistent model of the soft X-ray background (SXRB) and the ROSAT all-sky survey, we derive ... More
Collisions of solid ice in planetesimal formationJan 18 2016We present collision experiments of centimetre projectiles on to decimetre targets, both made up of solid ice, at velocities of $15\,\mathrm{m\,s^{-1}}$ to $45\,\mathrm{m\,s^{-1}}$ at an average temperature of $\mathrm{T_{avg}}=255.8\pm0.7\,\mathrm{K}$. ... More
A model realisation of the Jaffe-Wilczek correlation for pentaquarksMar 22 2004We discuss a realisation of the pentaquark structure proposed by Jaffe and Wilczek within a simple quark model with colour-spin contact interactions and coloured harmonic confinement, which accurately describes the $\Delta-N$ splitting. In this model ... More
Recoil Polarization Measurements for Neutral Pion Electroproduction at Q^2=1 (GeV/c)^2 Near the Delta ResonanceSep 01 2005We measured angular distributions of differential cross section, beam analyzing power, and recoil polarization for neutral pion electroproduction at Q^2 = 1.0 (GeV/c)^2 in 10 bins of W across the Delta resonance. A total of 16 independent response functions ... More
Accuracy of traditional Legendre estimators of quadrupole ratios for the N to Delta transitionJul 06 2005We evaluate the accuracy of traditional estimators often used to extract N to Delta quadrupole ratios from cross section angular distributions for pion electroproduction. We find that neither M1+ dominance nor sp truncation is sufficiently accurate for ... More
Time-odd components in the mean field of rotating superdeformed nucleiFeb 10 1995Rotation-induced time-odd components in the nuclear mean field are analyzed using the Hartree-Fock cranking approach with effective interactions SIII, SkM*, and SkP. Identical dynamical moments ${{\cal J}^{(2)}}$ are obtained for pairs of superdeformed ... More