Results for "Daniel Hexner"

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Entropic commensurate-incommensurate transitionNov 29 2012Jan 26 2013The equilibrium properties of a minimal tiling model are investigated. The model has extensive ground state entropy, with each ground state having a quasiperiodic sequence of rows. It is found that the transition from the quasiperiodic ground state to ... More
Directed aging, memory and Nature's greedMar 14 2019Disordered materials are often out of equilibrium and evolve very slowly. This allows a memory of the imposed strains or preparation conditions to be encoded in the material. Here we consider "directed aging", where the elastic properties of a material ... More
Noise, diffusion, and hyperuniformityNov 08 2016We consider driven many-particle models which have a phase transition between an active and an absorbing phase. Like previously studied models, we have particle conservation, but here we introduce an additional symmetry - when two particles interact, ... More
Tug-of-war in motility assay experimentsMar 02 2009The dynamics of two groups of molecular motors pulling in opposite directions on a rigid filament is studied theoretically. To this end we first consider the behavior of one set of motors pulling in a single direction against an external force using a ... More
Hyperuniformity of critical absorbing statesJul 01 2014Aug 24 2014The properties of the absorbing states of non-equilibrium models belonging to the conserved directed percolation universality class are studied. We find that at the critical point the absorbing states are hyperuniform, exhibiting anomalously small density ... More
Self Organization and Self Avoiding Limit CyclesJan 05 2014A simple periodically driven system displaying rich behavior is introduced and studied. The system self-organizes into a mosaic of static ordered regions with three possible patterns, which are threaded by one-dimensional paths on which a small number ... More
Can a large packing be assembled from smaller ones?Feb 02 2019We consider zero temperature packings of soft spheres, that undergo a jamming to unjamming transition as a function of packing fraction. We compare differences in the structure, as measured from the contact statistics, of a finite subsystem of a large ... More
Role of local response in manipulating the elastic properties of disordered solids by bond removalAug 23 2017We explore the range over which the elasticity of disordered spring networks can be manipulated by the removal of selected bonds. By taking into account the local response of a bond, we demonstrate that the effectiveness of pruning can be improved so ... More
Two diverging length scales in the structure of jammed packingsOct 19 2017Jun 11 2018At densities higher than the jamming transition for athermal, frictionless repulsive spheres we find two distinct length scales, both of which diverge as a power law as the transition is approached. The first, $\xi_{Z}$, is associated with the two-point ... More
Linking microscopic and macroscopic response in disordered solidsJun 19 2017The modulus of a rigid network of harmonic springs depends on the sum of the energies in each of the bonds due to the applied distortion: compression in the case of the bulk modulus, $B$, or shear in the case of the shear modulus, $\mathcal{G}$. The distortion ... More
Amorphous topological insulators constructed from random point setsDec 29 2016Oct 09 2018The discovery that the band structure of electronic insulators may be topologically non-trivial has unveiled distinct phases of electronic matter with novel properties. Recently, mechanical lattices have been found to have similarly rich structure in ... More
An Extended Kalman Filter with a Computed Mean Square Error BoundOct 01 2014The paper proposes a new recursive filter for non-linear systems that inherently computes a valid bound on the mean square estimation error. The proposed filter, bound based extended Kalman, (BEKF) is in the form of an extended Kalman filter. The main ... More
Casimir force in O(n) lattice models with a diffuse interfaceJun 23 2008On the example of the spherical model we study, as a function of the temperature $T$, the behavior of the Casimir force in O(n) systems with a diffuse interface and slab geometry $\infty^{d-1}\times L$, where $2<d<4$ is the dimensionality of the system. ... More
Fragmentation in Kinematically Cold DisksJan 16 2001Gravity is scale free. Thus gravity may form similar structures in self-gravitating systems on different scales. Indeed, observations of the interstellar medium, spiral disks and cosmic structures, reveal similar characteristics. The structures in these ... More
Extending polynomials in maximal and minimal idealsOct 20 2009Feb 08 2010Given an homogeneous polynomial on a Banach space $E$ belonging to some maximal or minimal polynomial ideal, we consider its iterated extension to an ultrapower of $E$ and prove that this extension remains in the ideal and has the same ideal norm. As ... More
Unconditionality in tensor products and ideals of polynomials, multilinear forms and operatorsJun 17 2009Feb 08 2010We study tensor norms that destroy unconditionality in the following sense: for every Banach space $E$ with unconditional basis, the $n$-fold tensor product of $E$ (with the corresponding tensor norm) does not have unconditional basis. We establish an ... More
A Field Range Bound for General Single-Field InflationNov 13 2011We explore the consequences of a detection of primordial tensor fluctuations for general single-field models of inflation. Using the effective theory of inflation, we propose a generalization of the Lyth bound. Our bound applies to all single-field models ... More
Five basic lemmas for symmetric tensor products of normed spacesMay 18 2011We give the symmetric version of five lemmas which are essential for the theory of tensor products (and norms). These are: the approximation, extension, embedding, density and local technique lemmas. Some application of these tools to the metric theory ... More
Scaling Laws in Self-Gravitating DisksApr 16 1999The interstellar medium (ISM) reveals strongly inhomogeneous structures at every scale. These structures do not seem completely random since they obey certain power laws. Larson's law (\citeyear{Larson81}) $\sigma \propto R^{\delta}$ and the plausible ... More
Supergravity for Effective TheoriesSep 01 2011Higher-derivative operators are central elements of any effective field theory. In supersymmetric theories, these operators include terms with derivatives in the K\"ahler potential. We develop a toolkit for coupling such supersymmetric effective field ... More
Inflating with BaryonsSep 15 2010We present a field theory solution to the eta problem. By making the inflaton field the phase of a baryon of SU(N_c) supersymmetric Yang-Mills theory we show that all operators that usually spoil the flatness of the inflationary potential are absent. ... More
Natural symmetric tensor normsFeb 22 2010Dec 14 2010In the spirit of the work of Grothendieck, we introduce and study natural symmetric n-fold tensor norms. We prove that there are exactly six natural symmetric tensor norms for $n\ge 3$, a noteworthy difference with the 2-fold case in which there are four. ... More
Equilateral Non-Gaussianity and New Physics on the HorizonFeb 25 2011Mar 23 2011We examine the effective theory of single-field inflation in the limit where the scalar perturbations propagate with a small speed of sound. In this case the non-linearly realized time-translation symmetry of the Lagrangian implies large interactions, ... More
Formalizing and Checking Thread Refinement for Data-Race-Free Execution Models (Extended Version)Oct 24 2015When optimizing a thread in a concurrent program (either done manually or by the compiler), it must be guaranteed that the resulting thread is a refinement of the original thread. Most theories of valid optimizations are formulated in terms of valid syntactic ... More
The symmetric Radon-Nikodým property for tensor normsMay 15 2010We introduce the symmetric-Radon-Nikod\'ym property (sRN property) for finitely generated s-tensor norms $\beta$ of order $n$ and prove a Lewis type theorem for s-tensor norms with this property. As a consequence, if $\beta$ is a projective s-tensor norm ... More
Desensitizing Inflation from the Planck ScaleApr 21 2010A new mechanism to control Planck-scale corrections to the inflationary eta parameter is proposed. A common approach to the eta problem is to impose a shift symmetry on the inflaton field. However, this symmetry has to remain unbroken by Planck-scale ... More
Signatures of Supersymmetry from the Early UniverseSep 01 2011Oct 11 2011Supersymmetry plays a fundamental role in the radiative stability of many inflationary models. Spontaneous breaking of the symmetry inevitably leads to fields with masses of order the Hubble scale during inflation. When these fields couple to the inflaton ... More
Contruction of holomorphic parameters invariant by change of variable in the Gauss-Manin connection of an holomorphic map to a discJan 20 2011When we consider a proper holomorphic map \ $\tilde{f}: X \to C$ \ of a complex manifold \ $X$ \ on a smooth complex curve \ $C$ \ with a critical value at a point \ $0$ \ in \ $C$, the choice of a local coordinate near this point allows to dispose of ... More
Finiteness of the space of n-cycles for a n-concave complex spaceAug 19 2015We show that for n $\ge$ 2 the space of closed n--cycles in a strongly n--concave complex space has a natural structure of reduced complex space locally of finite dimension and represents the functor "analytic family of n--cycles" parametrized by banach ... More
Statistical measure of complexity for quantum systems with continuous variablesMay 03 2011Jul 24 2012The Fisher-Shannon statistical measure of complexity is analyzed for a continuous manifold of quantum observables. It is probed then than calculating it only in the configuration and momentum spaces will not give a complete description for certain systems. ... More
SYNTAGMA. A Linguistic Approach to ParsingMar 24 2013Jan 21 2016SYNTAGMA is a rule-based parsing system, structured on two levels: a general parsing engine and a language specific grammar. The parsing engine is a language independent program, while grammar and language specific rules and resources are given as text ... More
Optimization-based smoothing algorithm for triangle meshes over arbitrarily shaped domainsOct 22 2014This paper describes a node relocation algorithm based on nonlinear optimization which delivers excellent results for both unstructured and structured plane triangle meshes over convex as well as non-convex domains with high curvature. The local optimization ... More
Graph Isomorphism for unit square graphsFeb 26 2016Jun 22 2016In the past decades for more and more graph classes the Graph Isomorphism Problem was shown to be solvable in polynomial time. An interesting family of graph classes arises from intersection graphs of geometric objects. In this work we show that the Graph ... More
Self-Gravitating N-Body Systems out of EquilibriumOct 19 2000Real physical systems are often maintained off equilibrium by energy or matter flows. If these systems are far from equilibrium then the thermodynamical branch become unstable and fluctuations can lead them to other more stable states. These new states ... More
Deriving Procedural and Warning Instructions from Device and Environment ModelsJun 24 1995Jun 24 1995This study is centred on the generation of instructions for household appliances. We show how knowledge about a device, together with knowledge about the environment, can be used for reasoning about instructions. The information communicated by the instructions ... More
Fast Universal Quantum Computation with Railroad-switch Local HamiltoniansAug 28 2009Sep 30 2009We present two universal models of quantum computation with a time-independent, frustration-free Hamiltonian. The first construction uses 3-local (qubit) projectors, and the second one requires only 2-local qubit-qutrit projectors. We build on Feynman's ... More
Local Hamiltonians in Quantum ComputationAug 15 2008In this thesis, I investigate aspects of local Hamiltonians in quantum computing. First, I focus on the Adiabatic Quantum Computing model, based on evolution with a time dependent Hamiltonian. I show that to succeed using AQC, the Hamiltonian involved ... More
Fault-Tolerant Quantum Computation with Higher-Dimensional SystemsFeb 02 1998Instead of a quantum computer where the fundamental units are 2-dimensional qubits, we can consider a quantum computer made up of d-dimensional systems. There is a straightforward generalization of the class of stabilizer codes to d-dimensional systems, ... More
An Introduction to Quantum Error Correction and Fault-Tolerant Quantum ComputationApr 16 2009Quantum states are very delicate, so it is likely some sort of quantum error correction will be necessary to build reliable quantum computers. The theory of quantum error-correcting codes has some close ties to and some striking differences from the theory ... More
Khovanov homology for virtual tangles and applicationsDec 02 2012We extend the cobordism based categorification of the virtual Jones polynomial to virtual tangles. This extension is combinatorial and has semi-local properties. We use the semi-local property to prove an applications, i.e. we give a discussion of Lee's ... More
Modeling the response of a recovering SiPMNov 20 2015Mar 17 2016We develop from first principles a model to describe the average response of SiPM devices which takes into account the recovery of pixels during the incoming light pulse. Such effects can significantly affect SiPM response when exposed to a large number ... More
Attracting Lagrangian Coherent Structures on Riemannian manifoldsNov 20 2013Jul 24 2015It is a wide-spread convention to identify repelling Lagrangian Coherent Structures (LCSs) with ridges of the forward finite-time Lyapunov exponent (FTLE) field, and attracting LCSs with ridges of the backward FTLE. We show that in two-dimensional incompressible ... More
Scale Interactions and Galaxy EvolutionDec 13 2002To understand galaxies and their evolution, it is necessary to describe how the different scales interact: how the microscopic physics, such as star formation, or the large scale physics, such as galaxy interactions may modify the galaxy global shapes. ... More
Which thermal physics for gravitationally unstable media?Jun 10 1998We remind that the assumptions almost universally adopted among astronomers concerning the physics to use to describe rarefied cosmic gases remain often without justifications, mainly because the long range of gravitation invalidates the use of classical ... More
Chaos in GalaxiesFeb 22 2008After general considerations about limits of theories and models, where small changes may imply large effects, we discuss three cases in galactic astrophysics illustrating how galactic dynamics models may become insufficient when previously neglected ... More
Framing and the Self-Linking IntegralNov 14 2002Apr 02 2004The Gauss self-linking integral of an unframed knot is not a knot invariant, but it can be turned into an invariant by adding a correction term which requires adding extra structure to the knot. We collect the different definitions/theorems/proofs concerning ... More
An Overview of the State of the Art for Practical Quantum Key DistributionApr 21 2015May 15 2015This is an overview of the state of the art for practical quantum key distribution (QKD) as of March 2015. It is written by a non-expert for non-experts. Additions and corrections are welcome.
Magnetohydrodynamic simulations of the collapsar model for early and late evolution of gamma-ray burstsJan 06 2007I present results from magnetohydrodynamic (MHD) simulations of a gaseous envelope collapsing onto a black hole. These results support the notion that the collapsar model is one of most promising scenarios to explain the huge release of energy in a matter ... More
The MHD collapsar model for GRBs: an inflow produces an outflowDec 09 2005We present our recent results from numerical simulations of a magnetized flow in the vicinity of a black hole in the context of the collapsar model for GRBs. The simulations show that after an initial transient, the flow settles into a complex convolution ... More
Theory of Outflows in Cataclysmic VariablesNov 08 2004We review the main results from line-driven (LD) models of winds from accretion disks in cataclysmic variables (CVs). We consider LD disk wind models in the hydrodynamic (HD) and magnetohydrodynamic (MHD limits. We discuss the basic physical conditions ... More
Dynamics of radiatively inefficient flows accreting onto radiatively efficient black hole objectsOct 12 2006I present results from numerical simulations of gas dynamics outside luminous accretion disks in active galactic nuclei. The gas, gravitationally captured by a super massive black hole, can be driven away by the energy and momentum of the radiation emitted ... More
On MHD jet production in the collapsing and rotating envelopeFeb 24 2005Apr 21 2005We present results from axisymmetric, time-dependent hydrodynamical (HD) and magnetohydrodynamical (MHD) simulations of a gaseous envelope collapsing onto a black hole (BH). We consider gas with so small angular momentum that after an initial transient, ... More
Time Variability of Low Angular Momentum Flows Accreting onto Black Holes: A Natural Mechanism For Radiation FlaringSep 20 2004We present results from our magnetohydrodynamical simulations of accretion flows onto black holes. Our main focus is the interplay between inflows and related outflows. We consider applications of such flows to the Galatic center and low luminosity active ... More
On a possible node in the Sivers and Qiu-Sterman functionsMay 12 2011Jul 04 2011The possibility of a node in the x dependence of the Sivers and Qiu-Sterman functions is discussed in light of its importance for the experimental check of the overall sign change of the Sivers effect between semi-inclusive DIS and the Drell-Yan process. ... More
Transverse Lambda polarization at high energy collidersJul 19 2010Measurements of transverse polarization of Lambda hyperons produced in high energy pp collisions may help to address several open issues about Lambda production and polarization mechanisms, such as the amount of SU(3) breaking, the importance of gluons ... More
Sudakov suppression in azimuthal spin asymmetriesFeb 06 2001May 25 2001It is shown that transverse momentum dependent azimuthal spin asymmetries suffer from suppression due to Sudakov factors, in the region where the transverse momentum is much smaller than the large energy scale Q^2. The size and Q^2 dependence of this ... More
Transversity single spin asymmetriesJun 18 2001The theoretical aspects of two leading twist transversity single spin asymmetries, one arising from the Collins effect and one from the interference fragmentation functions, are reviewed. Issues of factorization, evolution and Sudakov factors for the ... More
Investigating the origins of transverse spin asymmetries at RHICFeb 05 1999Feb 22 1999We discuss possible origins of transverse spin asymmetries in hadron-hadron collisions and propose an explanation in terms of a chiral-odd T-odd distribution function with intrinsic transverse momentum dependence, which would signal a correlation between ... More
On derived categories of K3 surfaces, symplectic automorphisms and the Conway groupSep 25 2013Sep 09 2014In this note we interpret a recent result of Gaberdiel, Hohenegger and Volpato in terms of derived equivalences of K3 surfaces. We prove that there is a natural bijection between subgroups of the Conway group Co_1 with invariant lattice of rank at least ... More
Chow groups of K3 surfaces and spherical objectsSep 15 2008Feb 12 2009We show that for a K3 surface X the finitely generated subring R(X) of the Chow ring introduced by Beauville and Voisin is preserved under derived equivalences. This is proved by analyzing Chern characters of spherical bundles. As for a K3 surface X defined ... More
Stability conditions via spherical objectsSep 22 2010An object in the bounded derived category D^b(Coh(X)) of coherent sheaves on a complex projective K3 surface X is spherical if it is rigid and simple. Although spherical objects form only a discrete set in the moduli stack of complexes, they determine ... More
Generalized Calabi-Yau structures, K3 surfaces, and B-fieldsJun 10 2003Sep 27 2004Generalized Calabi-Yau structures, a notion recently introduced by Hitchin, are studied in the case of K3 surfaces. We show how they are related to the classical theory of K3 surfaces and to moduli spaces of certain SCFT as studied by Aspinwall and Morrison. ... More
Moduli spaces of hyperkaehler manifolds and mirror symmetryOct 15 2002Jun 10 2003These are notes of my lectures given at the school on intersection theory and moduli at the ICTP, Trieste. We construct moduli spaces of K3 surfaces and higherdimensional hyperkaehler manifolds, including moduli spaces of (2,2)-conformal field theories ... More
Finiteness results for hyperkaehler manifoldsSep 04 2001In this short note we prove that the number of deformation types of compact hyperkaehler manifolds with prescribed second cohomology and second Chern class is finite. The proof uses the finiteness result of Kollar and Matsusaka, a formula by Hitchin and ... More
Infinitesimal Variation of Harmonic Forms and Lefschetz DecompositionFeb 15 2001Apr 27 2001This paper studies the infinitesimal variation of the Lefschetz decomposition associated with a compatible sl_2-representation on a graded algebra. This allows to prove that the Jordan-Lefschetz property holds infinitesimally for the Kaehler Lie algebra ... More
New fusion rules and $\cR$-matrices for $SL(N)_q$ at roots of unityDec 10 1991Feb 11 1992We derive fusion rules for the composition of $q$-deformed classical representations (arising in tensor products of the fundamental representation) with semi-periodic representations of $SL(N)_q$ at roots of unity. We obtain full reducibility into semi-periodic ... More
Backreaction of Localised Sources in String CompactificationsSep 23 2013Localised sources such as D-branes or orientifold planes play an important role in many string compactifications that are relevant for phenomenology. The presence of these objects typically induces complicated dynamics in the compact dimensions such that ... More
p-adic Heights of Heegner points on Shimura curvesApr 18 2013Oct 07 2015Let $f$ be a primitive Hilbert modular form of parallel weight $2$ and level $N$ for the totally real field $F$, and let $p$ be a rational prime coprime to $2N$. If $f$ is ordinary at $p$ and $E$ is a CM extension of $F$ of relative discriminant $\Delta$ ... More
Decomposition numbers for perverse sheavesMar 17 2008The purpose of this article is to set foundations for decomposition numbers of perverse sheaves, to give some methods to calculate them in simple cases, and to compute them concretely in two situations: for a simple (Kleinian) surface singularity, and ... More
Weak Forms of Monotonicity and Coordination-FreenessFeb 01 2012Our earlier work titled: "Win-move is Coordination-Free (Sometimes)" has shown that the classes of queries that can be distributedly computed in a coordination-free manner form a strict hierarchy depending on the assumptions of the model for distributed ... More
D0 Top Quark Results and their Dependence on Successful Grid ComputingJul 27 2005The heaviest known Fermion particle -- the top quark -- was discovered at Fermilab in the first run of the Tevatron in 1995. However, besides its mere existence one needs to study its properties precisely in order to verify or falsify the predictions ... More
Review on alpha_s at LEPNov 03 1999To measure the strong coupling alpha_s from event shape observables two ingredients are necessary. A perturbative prediction containing the dependence of observables on alpha_s and a description of the hadronisation process to match the perturbative prediction ... More
Testing the Standard Model in Top Quark DecaysOct 14 2006With its discovery in 1995 by the CDF and D0 collaborations the top quark completed the set of quarks expected by the Standard Model. It is predicted to have the same quantum numbers and couplings as the other up-type quarks. Albeit, only very few of ... More
CP violation, the CKM matrix and New PhysicsJan 23 2001Mar 22 2001Loop corrections for physics beyond the Standard Model are computed. DWe discuss the influence of new physics on CP-violating observables. Assuming the standard model gives a correct description of tree level processes, we show how a consistent procedure ... More
Transformation methods for evaluating approximations to the optimal exercise boundary for linear and nonlinear Black-Scholes equationsMay 05 2008The purpose of this survey chapter is to present a transformation technique that can be used in analysis and numerical computation of the early exercise boundary for an American style of vanilla options that can be modelled by class of generalized Black-Scholes ... More
Analytical solutions of basic models in quantum opticsSep 18 2015The recent progress in the analytical solution of models invented to describe theoretically the interaction of matter with light on an atomic scale is reviewed. The methods employ the classical theory of linear differential equations in the complex domain ... More
Note on the Analytical Solution of the Rabi ModelOct 17 2012Nov 23 2012It is shown that a recent critique (arXiv:1210.1130 and arXiv:1211.4639) concerning the analytical solution of the Rabi model is unfounded.
On the Integrability of the Rabi ModelMar 12 2011Dec 20 2011The exact spectrum of the Rabi hamiltonian is analytically found for arbitrary coupling strength and detuning. I present a criterion for integrability of quantum systems containing discrete degrees of freedom which shows that in this case a finite symmetry ... More
Holonomic modules over Cherednik algebras, IAug 04 2016The goal of this paper is to generalize several basic results from the theory of $\cal{D}$-modules to the representation theory of rational Cherednik algebras. We relate characterizations of holonomic modules in terms of singular support and Gelfand-Kirillov ... More
Périodes évanescentes et $(a,b)$-modules monogènesJan 14 2009In order to describe the asymptotic behaviour of a vanishing period in a one parameter family we introduce and use a very simple algebraic structure : regular geometric (a,b)-modules generated (as left $\A-$modules) by one element. The idea is to use ... More
Sur les fonctions à singularité de dimension 1Sep 04 2007In this article we show that all results proved for a large class of holomorphic germs $f : (\mathbb{C}^{n+1}, 0) \to (\mathbb{C}, 0)$ with a 1-dimension singularity in [B.II] are valid for an arbitrary such germ.
Quantum field theories of extended objectsMay 11 2016First steps are taken in a project to construct a general class of conformal and perhaps, eventually, non-conformal quantum field theories of (n-1)-dimensional extended objects in a d=2n dimensional conformal space-time manifold M. The fields live on ... More
Gas-Rich Local Dwarf Star-Forming Galaxies and their connection with the Distant UniverseDec 17 1998I discuss the properties of gas-rich forming galaxies. I particularly emphasize the latest results on Lyman alpha emission that are relevant to the search of distant young galaxies. The interdependance of the Lyman alpha escape with the properties of ... More
The BHK Color Diagram: a New Tool to Study Young Stellar PopulationsApr 01 1999A new method to derive age differences between the various super star clusters observed in starburst galaxies using the two color diagram (B-H) vs (H-K) is presented. This method offers a quick and easy way to differentiate very young and intermediate ... More
Gysin functors and the Grothendieck-Witt category, Part IFeb 01 2016We define the Grothendieck-Witt category over a fixed ground ring. In order to study the structure of this category, we introduce the general theory of Gysin functors and their associated categories of correspondences. The latter generalizes the familiar ... More
A proof of Sageev's Theorem on hyperplanes in CAT(0) cubical complexesSep 04 2009Oct 24 2009We prove that a hyperplane in a CAT(0) cubical complex X has no self-intersections and separates X into two convex complementary components. These facts were originally proved by Sageev. Our argument shows that his theorem is a corollary of Gromov's link ... More
Equivariant cohomology and the Varchenko-Gelfand filtrationOct 24 2011May 11 2012The cohomology of the configuration space of n points in R^3 admits a symmetric group action and has been shown to be isomorphic to the regular representation. One way to prove this is by defining an S^1-action whose fixed point set is the complement ... More
Tight-Binding study of the electronic and magnetic properties of an L1_0 ordered FeCu alloyJun 07 1997We have calculated the electronic structure of the tetragonal L1$_0$ ordered FeCu by solving self-consistently a tight-binding Hamiltonian for s, p and d electrons. We have found by total energy calculation that this structure is ferromagnetic. In addition, ... More
Improving the understanding of the melting behaviour of Mo, Ta, and W at extreme pressuresAug 09 2004Nov 30 2004We discus existent conflicts between experimentally measured and theoretically calculated melting curves of Mo, Ta, and W. By assuming that vacancy formation plays a fundamental role in the melting process, an explanation for the measured melting curves ... More
Extragalactic Propagation of Ultra-High Energy Cosmic RaysSep 10 2014Sep 20 2014More than 100 years after the discovery of cosmic rays and various experimental efforts, the origin of ultra-high energy cosmic rays (E > 100 PeV) remains unclear. The understanding of production and propagation effects of these highest energetic particles ... More
The stochastic system approach to causality with a view toward lifecourse epidemiologyMar 26 2012The approach of causality based on physical laws and systems is revisited. The issue of "levels", the relevance to epidemiology and the definition of effects are particularly developed. Moreover it is argued that this approach that we call the stochastic ... More
A presentation of Quantum Logic based on an "and then" connectiveJan 16 2007When a physicist performs a quantic measurement, new information about the system at hand is gathered. This paper studies the logical properties of how this new information is combined with previous information. It presents Quantum Logic as a propositional ... More
Classes of service under perfect competition and technological change: a model for the dynamics of the Internet?Feb 20 2002Certain services may be provided in a continuous, one-dimensional, ordered range of different qualities and a customer requiring a service of quality q can only be offered a quality superior or equal to q. Only a discrete set of different qualities will ... More
Relativistic Lighthouses: The Role of the Binary Pulsar in proving the existence of Gravitational WavesJul 08 2014This paper discusses the role of the discovery and analysis of the first binary pulsar in settling the long-running quadrupole formula controversy over the status of gravitational waves as a prediction of general relativity. It also discusses how we should ... More
Explicit error bounds for lazy reversible Markov Chain Monte CarloMay 23 2008Jan 16 2011We prove explicit, i.e., non-asymptotic, error bounds for Markov Chain Monte Carlo methods, such as the Metropolis algorithm. The problem is to compute the expectation (or integral) of f with respect to a measure which can be given by a density with respect ... More
Lattices in the cohomology of $U(3)$ arithmetic manifoldsJul 16 2015Under hypotheses required for the Taylor-Wiles method, we prove for forms of $U(3)$ which are compact at infinity that the lattice structure on upper alcove algebraic vectors or on principal series types given by the $\lambda$-isotypic part of completed ... More
Projective multiplets and hyperkahler cones in conformal supergravityOct 14 2014Feb 09 2015Projective superspace provides a natural framework for the construction of actions coupling hypermultiplets to conformal supergravity. We review how the off-shell actions are formulated in superspace and then discuss how to eliminate the infinite number ... More
A new approach to curved projective superspaceJun 24 2014Sep 15 2014We present a new formulation of curved projective superspace. The 4D N=2 supermanifold M^{4|8} (four bosonic and eight Grassmann coordinates) is extended by an auxiliary SU(2) manifold, which involves introducing a vielbein and related connections on ... More
Towards Collisions of Inhomogeneous Shockwaves in AdSJul 21 2014Jun 21 2015We perform a numerical simulation of the evolution of inhomogeneities with transverse profile in a collision of gravitational shockwaves in asymptotically anti-de Sitter spacetime. This constitutes a step closer towards an accurate holographic description ... More
On scalar-valued nonlinear absolutely summing mappingsOct 10 2003Oct 24 2003In this note we show that the well known coincidence results for scalar-valued homogeneous polynomials can not be generalized in some natural directions.