Results for "Giacomo Prando"

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Anomalous lattice contraction and emergent electronic phases in Bi-doped Eu$_2$Ir$_2$O$_7$Feb 08 2019We study the pyrochlore series (Eu$_{1-x}$Bi$_x$)$_2$Ir$_2$O$_7$ for $ 0 \leq x \leq 1$. We show that for small $x$, the lattice undergoes an anomalous contraction but the all-in/all-out and metal-to-insulator transitions remain robust, and the resistivity ... More
Effects of quantum impurity spins on the magnetic properties of zigzag and linear spin chainsFeb 11 2016We investigated the magnetic ground state and low-energy excitations of the spin chains compounds SrCuO$_{2}$ (zigzag chains) and Sr$_{2}$CuO$_{3}$ (linear chains) in the presence of quantum impurities induced by lightly doping ($\leq 1 \%$) with Zn$^{2+}$ ... More
Decay of energy and suppression of Fermi acceleration in a dissipative driven stadium-like billiardFeb 15 2011Nov 22 2011The behavior of the average energy for an ensemble of non-interacting particles is studied using scaling arguments in a dissipative time-dependent stadium-like billiard. The dynamics of the system is described by a four dimensional nonlinear mapping. ... More
Classical vs. Bayesian methods for linear system identification: point estimators and confidence setsJul 02 2015This paper compares classical parametric methods with recently developed Bayesian methods for system identification. A Full Bayes solution is considered together with one of the standard approximations based on the Empirical Bayes paradigm. Results regarding ... More
Higgs and Beyond Standard Model Searches at LEPNov 06 2004Extensive searches for Higgs bosons and other new phenomena predicted by extensions of the Standard Model have been performed at LEP. A summary is given reviewing the principal aspects and presenting a selection of results.
Relativity Experiments in the Solar SystemApr 27 1995Recent theoretical works on alternative metric theories of gravity give greater significance to solar-system tests of General Relativity. In particular, it is suggested that the post-Newtonian parameter $\gamma$ ought to be determined with great precision ... More
Cryptanalysis of a non-commutative key exchange protocolJun 22 2013In the papers by Alvarez et al. and Pathak and Sanghi a non-commutative based public key exchange is described. A similiar version of it has also been patented (US7184551). In this paper we present a polynomial time attack that breaks the variants of ... More
Results on heavy ion physics at LHCbApr 08 2019In the last years, the \lhcb experiment established itself as an important contributor to heavy ion physics by exploiting some of its specific features. Production of particles, notably heavy flavour states, can be studied in p-p, p-Pb and Pb-Pb collisions ... More
Epitopological and pseudotopological fundamental group functorsJul 18 2017In these notes the epitopological and pseudotopological fundamental group functors are introduced. These are functors from the category of pointed epitopological and pseudotopological spaces respectively, to the category of their respective group-objects. ... More
$κ$-de Sitter and $κ$-Poincaré symmetries emerging from Chern-Simons (2+1)D gravity with a cosmological constantJun 09 2017Sep 15 2017Defining a new r-matrix compatible with the scalar product at the basis of the Chern-Simons action for a particle coupled to (2+1) Lorentzian gravity with cosmological constant, I show how deformed symmetries of $\kappa$-de Sitter and, in the vanishing ... More
Further Results on the Convergence of the Pavon-Ferrante Algorithm for Spectral EstimationDec 12 2016Jan 25 2018In this paper, we provide a detailed analysis of the global convergence properties of an extensively studied and extremely effective fixed-point algorithm for the Kullback-Leibler approximation of spectral densities, proposed by Pavon and Ferrante in ... More
Precision Electroweak Physics and Higgsless Models in Warped SpaceSep 14 2004We study tree level corrections to precision electroweak physics in the recently proposed Higgsless models in warped space. Such models inherit from their similarity with technicolor theories a large contribution to the oblique parameters, S in particular. ... More
SUSY Particles Searches at LEP and Interpretations within the MSSMOct 08 2002Searches for R-parity conserving supersymmetric particles have been performed in e+e- data collected by LEP detectors, at centre-of-mass energies up to 209GeV, corresponding to an integrated luminosity of 3.1fb-1. The results and their interpretation ... More
The Construction of the CMS Silicon Strip TrackerJan 16 2008The CMS Silicon Strip tracker is a very large scale tracker entirely based on silicon strip detectors technology. The integration of modules, electronics, mechanics and services has been completed within the last eighteen months; first large standalone ... More
Compressing redundant information in Markov chainsMay 03 2006Jun 23 2006Given a strongly stationary Markov chain and a finite set of stopping rules, we prove the existence of a polynomial algorithm which projects the Markov chain onto a minimal Markov chain without redundant information. Markov complexity is hence defined ... More
An Introduction to Quantum Computing, Without the PhysicsAug 11 2017Nov 19 2018This paper is a gentle but rigorous introduction to quantum computing intended for discrete mathematicians. Starting from a small set of assumptions on the behavior of quantum computing devices, we analyze their main characteristics, stressing the differences ... More
Informed proposals for local MCMC in discrete spacesNov 20 2017There is a lack of methodological results to design efficient Markov chain Monte Carlo (MCMC) algorithms for statistical models with discrete-valued high-dimensional parameters. Motivated by this consideration, we propose a simple framework for the design ... More
On resilient control of dynamical flow networksJan 13 2017Jan 25 2019Resilience has become a key aspect in the design of contemporary infrastructure networks. This comes as a result of ever-increasing loads, limited physical capacity, and fast-growing levels of interconnectedness and complexity due to the recent technological ... More
Biaxiality in the asymptotic analysis of a 2-D Landau-de Gennes model for liquid crystalsJul 30 2013Jan 08 2014We consider the Landau-de Gennes variational problem on a bound\-ed, two dimensional domain, subject to Dirichlet smooth boundary conditions. We prove that minimizers are maximally biaxial near the singularities, that is, their biaxiality parameter reaches ... More
The construction and commissioning of the CMS Silicon Strip TrackerSep 19 2008Oct 06 2008As the start up date for LHC approaches, the detectors are readying for data taking. Here a review will be given on the construction phase with insights into the various difficulties encountered during the process. An overview will also be given of the ... More
Bayesian complementary clustering, MCMC and Anglo-Saxon placenamesSep 24 2014Jul 02 2015Common cluster models for multi-type point processes model the aggregation of points of the same type. In complete contrast, in the study of Anglo-Saxon settlements it is hypothesized that administrative clusters involving complementary names tend to ... More
The topologies of Supersymmetry signals at LEPSep 12 2002The topologies arising from the production of supersymmetric particles at the LEP collider are briefly reviewed recalling detector requirements, simulation and other experimental issues.
An Unexpected Effect in ALEPH: Long-Term Displacements of the Silicon Vertex DetectorMay 16 2002The ALEPH Silicon Vertex Detector for LEP2 featured a laser survey system to monitor its mechanical stability. The analysis of laser system data from 1997 to 2000 showed that VDET suffered a time-dependent displacement. It resulted to be compatible with ... More
Sinusoidal Gravitational Waves from the Nuclei of Active GalaxiesMay 26 1993It is believed that most quasars and galaxies present two common features: the presence in their core of a supermassive object, and the experience of one or more encounters with other galaxies. In this scenario, it is likely that a substantial fraction ... More
Generation of discrete random variables in scalable frameworkNov 21 2016In this paper, we face the problem of simulating discrete random variables with general and varying distribution in a scalable framework, where fully parallelizable operations should be preferred. Compared with classical algorithms, we add randomness, ... More
Line defects in the small elastic constant limit of a three-dimensional Landau-de Gennes modelJan 21 2015Apr 16 2016We consider the Landau-de Gennes variational model for nematic liquid crystals, in three-dimensional domains. More precisely, we study the asymptotic behaviour of minimizers as the elastic constant tends to zero, under the assumption that minimizers are ... More
CMS Inner Tracker Detector ModulesNov 06 2004The production of silicon detector modules that will instrument the CMS Inner Tracker has nowadays reached 1300 units out of the approximately 3700 needed in total, with an overall yield close to 96%. A description of the module design, the assembly procedures ... More
The CMS Si-strip TrackerFeb 03 2004The Compact Muon Solenoid (CMS) experiment at LHC features the largest Silicon Strip Tracker (SST) ever build. This device is immersed in a 4T magnetic field and, in conjunction with a Pixel system, it allows the momentum of the charged particles to be ... More
Almost periodic functions and hyperbolic countingOct 19 2016In this paper we prove the existence of asymptotic moments, and an estimate on the tails of the limiting distribution, for a specific class of almost periodic functions. Then we introduce the hyperbolic circle problem, proving an estimate on the asymptotic ... More
A frequency approach to topological identification and graphical modelingAug 07 2011This works explores and illustrates recent results developed by the author in field of dynamical network analysis. The considered approach is blind, i.e., no a priori assumptions on the interconnected systems are available. Moreover, the perspective is ... More
Observations of Gamma-ray Bursts in the Fermi eraApr 20 2013May 23 2013The Fermi observatory, with its Gamma-Ray Bursts monitor (GBM) and Large Area Telescope (LAT), is observing Gamma-ray Bursts with unprecedented spectral coverage and sensitivity, from ~10 keV to > 300 GeV. In the first 3 years of the mission it observed ... More
Analyzing the structure of basic quantum knowledge for instructionAug 12 2019In order to support students in the development of expertise in quantum mechanics (QM), as well as to provide insight on teaching, we asked which concepts and structures can act as organizing principles in basic QM (RQ1). The research question has been ... More
Game Theory (Open Access textbook with 165 solved exercises)Dec 21 2015This is an Open Access textbook on non-cooperative Game Theory with 165 solved exercises.
Performance of hybrid quantum/classical variational heuristics for combinatorial optimizationMay 30 2018Dec 13 2018The recent literature on near-term applications for quantum computers contains several examples of the applications of hybrid quantum/classical variational approaches. This methodology can be applied to a variety of optimization problems, but its practical ... More
The Moment Guided Monte Carlo method for the Boltzmann equationJul 04 2012Jul 09 2013In this work we propose a generalization of the Moment Guided Monte Carlo method developed in [11]. This approach permits to reduce the variance of the particle methods through a matching with a set of suitable macroscopic moment equations. In order to ... More
Sylvester's law of inertia for quadratic forms on vector bundlesJul 08 2013Aug 06 2013This paper presents a generalisation of Sylvester's law of inertia to real non-degenerate quadratic forms on a fixed real vector bundle over a connected locally connected paracompact Hausdorff space. By interpreting the classical inertia as a complete ... More
Results from cosmics and first LHC beam with the ALICE HMPID detectorJul 27 2009Sep 21 2009The ALICE HMPID (High Momentum Particle IDentification) detector has been designed to identify charged pions and kaons in the range 1 < p < 3 GeV/c and protons in the range 1.5 < p < 5 GeV/c. It consists of seven identical proximity focusing RICH (Ring ... More
Gravitational Waves from a Population of Galactic Neutron StarsJan 05 1998The existence of a large number of asymmetric, rotating neutron stars, each individually emitting periodic or quasi-periodic gravitational waves in the frequency band around 100 Hz, raises the possibility of detecting their combined signals, by exploiting ... More
Induced paramagnetic states by localized $π$-loops in grain boundariesMar 11 2003Recent experiments on high-temperature superconductors show paramagnetic behavior localized at grain boundaries (GB). This paramagnetism can be attributed to the presence unconventional d-wave induced $\pi$-junctions. By modeling the GB as an array of ... More
Massive binary star mergers in galactic nuclei: implications for blue stragglers, binary S-stars and gravitational wavesMar 07 2019Most of the stars are believed to be born in binaries or higher-multiplicity systems. The implications of the presence of a binary population in galactic nuclei have been under scrutiny only recently. Observations suggest that our Galactic Centre harbours ... More
Tidal breakup of quadruple stars in the Galactic CentreApr 26 2018Jun 07 2018The most likely origin of hypervelocity stars (HVSs) is the tidal disruption of a binary star by the supermassive black hole (MBH) in the Galactic Centre (GC). However, HE0437-5439, a $9$ M$_\odot$ B-type main-sequence star moving with a heliocentric ... More
Dynamical origin of S-type planets in close binary starsDec 06 2018Understanding the origin of planets that have formed in binary stars is fundamental to constrain theories of binary and planet formation. The planet occurrence rate in binaries with a separation $\lesssim 50$ AU is only $\sim$ one third that of wider ... More
The Temporal Singularity: time-accelerated simulated civilizations and their implicationsJun 22 2018Provided significant future progress in artificial intelligence and computing, it may ultimately be possible to create multiple Artificial General Intelligences (AGIs), and possibly entire societies living within simulated environments. In that case, ... More
Likelihood test in permutations with bias. Premier League and La Liga: surprises during the last 25 seasonsJul 23 2017Aug 01 2017In this paper, we introduce the models of permutations with bias, which are random permutations of a set, biased by some preference values. We present a new parametric test, together with an efficient way to calculate its p-value. The final tables of ... More
Nbd is not cartesian closedJul 19 2017In this short note it is shown that the category of neighborhood spaces is not cartesian closed.
The emergence of the concept of filter in topological categoriesJul 19 2017In all approaches to convergence where the concept of filter is taken as primary, the usual motivation is the notion of neighborhood filter in a topological space. However, these approaches often lead to spaces more general than topological ones, thereby ... More
Effect of external pressure on the magnetic properties of LnFeAsO (Ln = La, Ce, Pr, Sm)May 11 2012We investigate the effect of external pressure on magnetic order in undoped LnFeAsO (Ln = La, Ce, Pr, La) by using muon-spin relaxation measurements and ab-initio calculations. Both magnetic transition temperature $T_m$ and Fe magnetic moment decrease ... More
Magnetic properties of spin diluted iron pnictides from muSR and NMR in LaFe1-xRuxAsOOct 21 2011The effect of isoelectronic substitutions on the microscopic properties of LaFe1-xRuxAsO, for 0< x< 0.8, has been investigated by means of muSR and 139La NMR. It was found that Ru substitution causes a progressive reduction of the N\`eel temperature (T_N) ... More
Direct evidence for the emergence of a pressure induced nodal superconducting gap in the iron-based superconductor Ba_0.65Rb_0.35Fe_2As_2May 05 2015Identifying the superconducting (SC) gap structure of the iron-based high-temperature superconductors (Fe-HTS's) remains a key issue for the understanding of superconductivity in these materials. In contrast to other unconventional superconductors, in ... More
Amorphous ferromagnetism and re-entrant magnetic glassiness in Sm$_{2}$Mo$_{2}$O$_{7}$: new insights into the electronic phase diagram of pyrochlore molybdatesMay 26 2014We discuss the magnetic properties of a Sm$_{2}$Mo$_{2}$O$_{7}$ single crystal as investigated by means of different experimental techniques. In the literature, a conventional itinerant ferromagnetic state is reported for the Mo$^{4+}$ sublattice below ... More
AC susceptibility investigation of vortex dynamics in nearly-optimally doped REFeAsO$_{1-x}$F$_{x}$ superconductors (RE = La, Ce, Sm)Dec 30 2011Ac susceptibility and static magnetization measurements were performed in the nearly-optimally doped LaFeAsO$_{0.9}$F$_{0.1}$ and CeFeAsO$_{0.92}$F$_{0.08}$ superconductors, complementing earlier results on SmFeAsO$_{0.8}$F$_{0.2}$ [Phys. Rev. {\bf B ... More
Superconducting phase fluctuations in SmFeAsO$_{0.8}$F$_{0.2}$ from diamagnetism at low magnetic field above $T_{c}$Apr 07 2011Jul 03 2011Superconducting fluctuations (SF) in SmFeAsO$_{0.8}$F$_{0.2}$ (characterized by superconducting transition temperature $T_{c} \simeq 52.3$ K) are investigated by means of isothermal high-resolution dc magnetization measurements. The diamagnetic response ... More
Dynamical quantum phase transitions and broken-symmetry edges in the many-body eigenvalue spectrumOct 07 2012Many body models undergoing a quantum phase transition to a broken-symmetry phase that survives up to a critical temperature must possess, in the ordered phase, symmetric as well as non-symmetric eigenstates. We predict, and explicitly show in the fully-connected ... More
Abstraction and control techniques for non-stationary scheduling problemsNov 30 2009The paper faces the problem of scheduling from a new perspective, trying to bridge the gap between classical heuristic approaches and system identification and control strategies. To this aim, a complete mathematical formulation of a general scheduling ... More
Product of real spectral triplesNov 19 2010We construct the product of real spectral triples of arbitrary finite dimension (and arbitrary parity) taking into account the fact that in the even case there are two possible real structures, in the odd case there are two inequivalent representations ... More
Magnon condensation with finite degeneracy on the triangular latticeDec 20 2013May 09 2014We study the spin 1/2 triangular-lattice $J_1$-$J_2$-$J_3$ antiferromagnet close to the saturation field using the dilute Bose gas theory, where the magnetic structure is determined by the condensation of magnons. We focus on the case of ferromagnetic ... More
High order asymptotic-preserving schemes for the Boltzmann equationJan 31 2012Feb 23 2012In this note we discuss the construction of high order asymptotic preserving numerical schemes for the Boltzmann equation. The methods are based on the use of Implicit-Explicit (IMEX) Runge-Kutta methods combined with a penalization technique recently ... More
Moments of Wishart-Laguerre and Jacobi ensembles of random matrices: application to the quantum transport problem in chaotic cavitiesMar 14 2011Mar 16 2011We collect explicit and user-friendly expressions for one-point densities of the real eigenvalues $\{\lambda_i\}$ of $N\times N$ Wishart-Laguerre and Jacobi random matrices with orthogonal, unitary and symplectic symmetry. Using these formulae, we compute ... More
Exact Moment Scaling from Multiplicative NoiseNov 30 2009Feb 22 2010For a general class of diffusion processes with multiplicative noise, describing a variety of physical as well as financial phenomena, mostly typical of complex systems, we obtain the analytical solution for the moments at all times. We allow for a non ... More
Incremental Principal Component Analysis Exact implementation and continuity correctionsJan 23 2019This paper describes some applications of an incremental implementation of the principal component analysis (PCA). The algorithm updates the transformation coefficients matrix on-line for each new sample, without the need to keep all the samples in memory. ... More
On the Capacity of Memoryless Finite-State Multiple-Access Channels with Asymmetric State Information at the EncodersDec 09 2010A single-letter characterization is provided for the capacity region of finite-state multiple-access channels, when the channel state process is an independent and identically distributed sequence, the transmitters have access to partial (quantized) state ... More
Understanding Color ConfinementOct 09 2013Some aspects are discussed of the mechanism of color confinement in QCD by condensation of magnetic monopoles in the vacuum.
Confinement and dual superconductivity of QCD vacuumOct 05 2007The mechanism of dual superconductivity for confinement is reviewed.
Recent progress on color confinementOct 05 2007The status is reviewed of the dual superconductivity of QCD vacuum as a mechanism of color confinement.
Semi-analytic calculation of the monopole order parameter in QCDOct 18 2006The monopole order parameter of QCD is computed in terms of gauge invariant field strength correlators. Both quantities are partially known from numerical simulations on the lattice. A new insight results on the structure of the confining vacuum.
On the Boundedness in $H^{1/4}$ of the Maximal Square Function Associated with the Schroedinger EquationJul 09 2003A long standing conjecture for the linear Schroedinger equation states that 1/4 of derivative in $L^2$, in the sense of Sobolev spaces, suffices in any dimension for the solution to that equation to converge almost everywhere to the initial datum as the ... More
On Distributed Dynamic Pricing of Multiscale Transportation NetworksFeb 03 2019We study transportation networks controlled by dynamic feedback tolls. We focus on a multiscale model whereby the dynamics of the traffic flows are intertwined with those of the drivers' route choices. The latter are influenced by the current congestion ... More
Searching for production of dark matter in association with top quarks at the LHCDec 03 2018Feb 04 2019In the framework of spin-0 $s$-channel dark matter (DM) simplified models, we reassess the sensitivity of future LHC runs to the production of DM in association with top quarks. We consider two different missing transverse energy ($E_T^{\mathrm{miss}}$) ... More
Searching for heavy Higgs bosons in the $t \bar t Z$ and $t b W$ final statesJul 20 2018Sep 26 2018In the context of two-Higgs doublet models, we explore the possibility of searching for heavy Higgs bosons in the $t \bar t Z$ and $t bW$ final states. We develop realistic analyses strategies and in the case of the $t \bar t Z$ channel provide a detailed ... More
Hypervelocity stars from star clusters hosting Intermediate-Mass Black HolesAug 23 2018Hypervelocity stars (HVSs) represent a unique population of stars in the Galaxy reflecting properties of the whole Galactic potential, from the centre to the halo. Determining their origin is of fundamental importance to constrain the shape and mass of ... More
Introducer Concepts in n-Dimensional ContextsFeb 12 2018Concept lattices are well-known conceptual structures that organise interesting patterns-the concepts-extracted from data. In some applications, such as software engineering or data mining, the size of the lattice can be a problem, as it is often too ... More
Diagrammatic approach to orbital quantum impurities interacting with a many-particle environmentApr 09 2017Aug 10 2017Recently it was shown that an impurity exchanging orbital angular momentum with a surrounding bath can be described in terms of the angulon quasiparticle [Phys. Rev. Lett. 118, 095301 (2017)]. The angulon consists of a quantum rotor dressed by a many-particle ... More
LTI Stochastic Processes: a Behavioral PerspectiveApr 07 2017This paper revisits the definition of linear time-invariant (LTI) stochastic process within a behavioral systems framework. Building on [Willems, 2013], we derive a canonical representation of an LTI stochastic process and a physically grounded notion ... More
Physics Without Physics: The Power of Information-theoretical PrinciplesJan 23 2017David Finkelstein was very fond of the new information-theoretic paradigm of physics advocated by John Archibald Wheeler and Richard Feynman. Only recently, however, the paradigm has concretely shown its full power, with the derivation of quantum theory ... More
Average Size of Implicational BasesFeb 12 2018Implicational bases are objects of interest in formal concept analysis and its applications. Unfortunately, even the smallest base, the Duquenne-Guigues base, has an exponential size in the worst case. In this paper, we use results on the average number ... More
The long-term evolution of known resonant trans-Neptunian objectsApr 19 2017Aims. Numerous trans-Neptunian objects are known to be in mean-motion resonance with Neptune. We aim to describe their long-term orbital evolution (both past and future) by means of a one-degree-of-freedom secular model. In this paper, we focus only on ... More
An InfoVis Tool for Interactive Component-Based EvaluationJan 31 2019In this paper, we present an InfoVis tool based on Sankey diagrams for the exploration of large combinatorial combinations of IR components - the Grid of Points (GoP). The goal of this tool is to ease the comprehension of the behavior of single IR components ... More
A clock-less ultra-low power bit-serial LVDS link for Address-Event multi-chip systemsAug 18 2019We present a power efficient clock-less fully asynchronous bit-serial Low Voltage Differential Signaling (LVDS) link with event-driven instant wake-up and self-sleep features, optimized for high speed inter-chip communication of asynchronous address-events ... More
The $Λ$-invariant and topological pathways to influence sub-micron strength and crystal plasticityJun 04 2019In small volumes, sample dimensions are known to strongly influence mechanical behavior, especially strength and crystal plasticity. This correlation fades away at the so-called mesoscale, loosely defined at several micrometers in both experiments and ... More
Multi-scale variance reduction methods based on multiple control variates for kinetic equations with uncertaintiesDec 12 2018The development of efficient numerical methods for kinetic equations with stochastic parameters is a challenge due to the high dimensionality of the problem. Recently we introduced a multiscale control variate strategy which is capable to accelerate considerably ... More
Optimal asymptotic bounds for designs on manifoldsNov 30 2018We extend to the case of a $d$-dimensional compact connected oriented Riemannian manifold $\mathcal M$ the theorem of A. Bondarenko, D. Radchenko and M. Viazovska on the existence of $L$-designs consisting of $N$ nodes, for any $N\ge C_{\mathcal M} L^d$. ... More
A spectral universality theorem for Maass $L$-functionsNov 06 2018We show that for a positive proportion of Laplace eigenvalues $\lambda_j$ the associated Hecke-Maass $L$-functions $L(s,u_j)$ approximate with arbitrary precision any target function $f(s)$ on a closed disc with center in $3/4$ and radius $r<1/4$. The ... More
From local averaging to emergent global behaviors: the fundamental role of network interconnectionsSep 29 2015Feb 20 2016Distributed averaging is one of the simplest and most studied network dynamics. Its applications range from cooperative inference in sensor networks, to robot formation, to opinion dynamics. A number of fundamental results and examples scattered through ... More
On Mertens-Cesàro Theorem for Number FieldsSep 23 2014Sep 03 2015Let $K$ be a number field with ring of integers $\mathcal O$. After introducing a suitable notion of density for subsets of $\mathcal O$, generalizing that of natural density for subsets of $\mathbb Z$, we show that the density of the set of coprime $m$-tuples ... More
Topological Features of Online Social NetworksFeb 02 2012The importance of modeling and analyzing Social Networks is a consequence of the success of Online Social Networks during last years. Several models of networks have been proposed, reflecting the different characteristics of Social Networks. Some of them ... More
Energetics of native point defects in GaN: a density-functional studyApr 11 2017We study the formation energies of native point defects in GaN through density-functional theory. In our first-principles scheme, the band edges are positioned in accord with hybrid density functional calculations, thus yielding a band-gap in agreement ... More
Random time step probabilistic methods for uncertainty quantification in chaotic and geometric numerical integrationJan 04 2018Jul 27 2018A novel probabilistic numerical method for quantifying the uncertainty induced by the time integration of ordinary differential equations (ODEs) is introduced. Departing from the classical strategy to randomize ODE solvers by adding a random forcing term, ... More
An urn model with local reinforcement: a theoretical framework for a chi-squared goodness of fit test with a big sampleJun 26 2019Motivated by recent studies of big samples, this work aims at constructing a parametric model which is characterized by the following features: (i) a "local" reinforcement, i.e. a reinforcement mechanism mainly based on the last observations, (ii) a random ... More
Implicit-Explicit multistep methods for hyperbolic systems with multiscale relaxationApr 08 2019We consider the development of high order space and time numerical methods based on Implicit-Explicit (IMEX) multistep time integrators for hyperbolic systems with relaxation. More specifically, we consider hyperbolic balance laws in which the convection ... More
Binary interaction algorithms for the simulation of flocking and swarming dynamicsMar 04 2012Microscopic models of flocking and swarming takes in account large numbers of interacting individ- uals. Numerical resolution of large flocks implies huge computational costs. Typically for $N$ interacting individuals we have a cost of $O(N^2)$. We tackle ... More
A canonical form for Gaussian periodic processesFeb 28 2012This article provides a representation theorem for a set of Gaussian processes; this theorem allows to build Gaussian processes with arbitrary regularity and to write them as limit of random trigonometric series. We show via Karhunen-Love theorem that ... More
Inverse Ising problem for one-dimensional chains with arbitrary finite-range couplingsSep 26 2011Nov 15 2011We study Ising chains with arbitrary multispin finite-range couplings, providing an explicit solution of the associated inverse Ising problem, i.e. the problem of inferring the values of the coupling constants from the correlation functions. As an application, ... More
Robustness of large-scale stochastic matrices to localized perturbationsAug 31 2013May 16 2015Upper bounds are derived on the total variation distance between the invariant distributions of two stochastic matrices differing on a subset W of rows. Such bounds depend on three parameters: the mixing time and the minimal expected hitting time on W ... More
Interacting Generalized Pólya Urn SystemsJan 07 2016We consider a system of interacting Generalized P\'olya Urns (GPUs) having irreducible mean replacement matrices. The interaction is modeled through the probability to sample the colors from each urn, that is defined as convex combination of the urn proportions ... More
Towards an ultra efficient kinetic scheme Part II: The high order caseDec 02 2012In a recent paper we presented a new ultra efficient numerical method for solving kinetic equations of the Boltzmann type (G. Dimarco, R. Loubere, Towards an ultra efficient kinetic scheme. Part I: basics on the 689 BGK equation, J. Comp. Phys., (2013), ... More
Coherence-based multivariate analysis of high frequency stock market valuesMay 18 2008The paper tackles the problem of deriving a topological structure among stock prices from high frequency historical values. Similar studies using low frequency data have already provided valuable insights. However, in those cases data need to be collected ... More
Assessing Financial Model RiskJul 02 2013Jul 10 2013Model risk has a huge impact on any risk measurement procedure and its quantification is therefore a crucial step. In this paper, we introduce three quantitative measures of model risk when choosing a particular reference model within a given class: the ... More
Gradient of the Objective Function for an Anisotropic Centroidal Voronoi Tessellation (CVT) - A revised, detailed derivationAug 24 2014In their recent article (2010), Levy and Liu introduced a generalization of Centroidal Voronoi Tessellation (CVT) - namely the Lp-CVT - that allows the computation of an anisotropic CVT over a sound mathematical framework. In this article a new objective ... More
Approximation of target problems in Blackwell spacesJan 13 2009On a weakly Blackwell space we show how to define a Markov chain approximating problem, for the target problem. The approximating problem is proved to converge to the optimal reduced problem under different pseudometrics. A computational example of compression ... More
The squashed entanglement of the noiseless quantum Gaussian attenuator and amplifierMay 21 2019Jun 10 2019We determine the maximum squashed entanglement achievable between sender and receiver of the noiseless quantum Gaussian attenuators and amplifiers, and prove that it is achieved sending half of an infinitely squeezed two-mode vacuum state. The key ingredient ... More