Results for "Fabio Viola"

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Taming VAEsOct 01 2018In spite of remarkable progress in deep latent variable generative modeling, training still remains a challenge due to a combination of optimization and generalization issues. In practice, a combination of heuristic algorithms (such as hand-crafted annealing ... More
The Kinetics Human Action Video DatasetMay 19 2017We describe the DeepMind Kinetics human action video dataset. The dataset contains 400 human action classes, with at least 400 video clips for each action. Each clip lasts around 10s and is taken from a different YouTube video. The actions are human focussed ... More
Wonderful models for generalized Dowling arrangementsNov 02 2018For any triple given by a positive integer n, a finite group G, and a faithful representation V of G, one can describe a subspace arrangement whose intersection lattice is a generalized Dowling lattice in the sense of Hanlon. In this paper we construct ... More
On weak and strong solution operators for evolution equations coming from quadratic operatorsSep 03 2014Jul 12 2016We identify, through a change of variables, solution operators for evolution equations with generators given by certain simple first-order differential operators acting on Fock spaces. This analysis applies, through unitary equivalence, to a broad class ... More
Partition Functions of Non-Abelian Quantum Hall StatesJul 10 2010Dec 26 2010Partition functions of edge excitations are obtained for non-Abelian Hall states in the second Landau level, such as the anti-Read-Rezayi state, the Bonderson-Slingerland hierarchy and the Wen non-Abelian fluid, as well as for the non-Abelian spin-singlet ... More
The Chandra COSMOS legacy survey: Energy Spectrum of the Cosmic X-ray Background and constraints on undetected populationsFeb 03 2017Using {\em Chandra} observations in the 2.15 deg$^{2}$ COSMOS legacy field, we present one of the most accurate measurements of the Cosmic X-ray Background (CXB) spectrum to date in the [0.3-7] keV energy band. The CXB has three distinct components: contributions ... More
Learning models for visual 3D localization with implicit mappingJul 04 2018Dec 12 2018We consider learning based methods for visual localization that do not require the construction of explicit maps in the form of point clouds or voxels. The goal is to learn an implicit representation of the environment at a higher, more abstract level. ... More
Generative Temporal Models with Spatial Memory for Partially Observed EnvironmentsApr 25 2018Jul 19 2018In model-based reinforcement learning, generative and temporal models of environments can be leveraged to boost agent performance, either by tuning the agent's representations during training or via use as part of an explicit planning mechanism. However, ... More
Limits on Preserving Quantum Coherence using Multi-Pulse ControlSep 09 2010Apr 08 2011We explore the physical limits of pulsed dynamical decoupling methods for decoherence control as determined by finite timing resources. By focusing on a decohering qubit controlled by arbitrary sequences of $\pi$-pulses, we establish a non-perturbative ... More
Beam Instabilities in the Scale Free RegimeJan 18 2012The instabilities arising in a one-dimensional beam sustained by the diffusive photorefractive nonlinearity in out-of-equilibrium ferroelectrics are theoretically and numerically investigated. In the "scale-free model", in striking contrast with the well-known ... More
Joseph Mecke's last fragmentary manuscripts - a compilationMar 29 2017May 22 2017Summarizing results from Joseph Mecke's last fragmentary manuscripts, the generating function and the Laplace transform for nonnegative random variables are considered. The concept of thickening of a random variable, as an inverse operation to thinning ... More
Arbitrarily Accurate Dynamical Control in Open Quantum SystemsAug 11 2009Mar 22 2010We show that open-loop dynamical control techniques may be used to synthesize unitary transformations in open quantum systems in such a way that decoherence is perturbatively compensated for to a desired (in principle arbitrarily high) level of accuracy, ... More
Spatial STIT Tessellations -- Distributional Results for I-SegmentsAug 08 2011Dec 11 2011Three-dimensional random tessellations that are stable under iteration (STIT tessellations) are considered. They arise as a result of subsequent cell division, which implies that their cells are not face-to-face. The edges of the cell-dividing polygons ... More
WIMP Dark Matter and the First Stars: a critical overviewMar 22 2011If Dark Matter (DM) is composed by Weakly Interacting Massive Particles, its annihilation in the halos harboring the earliest star formation episode may strongly influence the first generation of stars (Population III). Whereas DM annihilation at early ... More
Self-annihilating dark matter and the CMB: reionizing the Universe and constraining cross sectionsDec 08 2009I summarize the recent advances in determining the effects of self-annihilating WIMP dark matter on the modification of the recombination history, at times earlier than the formation of astrophysical objects. Depending on mass and self-annihilation cross ... More
Dark Matter capture and annihilation on the First Stars: preliminary estimatesFeb 07 2008Apr 11 2008Assuming that Dark Matter is dominated by WIMPs, it accretes by gravitational attraction and scattering over baryonic material and annihilates inside celestial objects, giving rise to a "Dark Luminosity" which may potentially affect the evolution of stars. ... More
Effects of BBN on Population III starsDec 18 2003The presence (or absence) of CNO elements in the primordial gas determines different behaviours in population III stars formation and evolution: we therefore present an analysis of the main channels for the synthesis of these elements in BBN in order ... More
A sheafification theorem for doctrinesNov 06 2013Sep 04 2014We define the notion of sheaf in the context of doctrines. We prove the associate sheaf functor theorem. We show that grothendieck toposes and toposes obtained by the tripos to topos construction are instances of categories of sheaves for a suitable doctrine. ... More
Monge problem in metric measure spaces with Riemannian curvature-dimension conditionOct 15 2013We prove the existence of solutions for the Monge minimization problem, addressed in a metric measure space $(X,d,m)$ enjoying the Riemannian curvature-dimension condition $\RCD(K,N)$, with $N < \infty$. For the first marginal measure, we assume that ... More
Appearances of pseudo-bosons from Black-Scholes equationMar 09 2016It is a well known fact that the Black-Scholes equation admits an alternative representation as a Schr\"odinger equation expressed in terms of a non self-adjoint hamiltonian. We show how {\em pseudo-bosons}, linear or not, naturally arise in this context, ... More
A tripos based on compact Hausdorff spacesFeb 10 2016The category of compact Hausdorff spaces is the base of tripos. As such it can be freely completed to an elementary topos.
Stacks of ramified Galois coversJul 03 2013Given a finite, flat and finitely presented group scheme $G$ over some base $S$, we introduce the notion of ramified $G$-covers and study the moduli stack $G$-Cov they form. The thesis is divided in three parts. The first one concerns the case when $G$ ... More
Comparison of leading and next-to-leading logarithmic electroweak corrections to Higgs productionMar 13 2013Jul 29 2013Using soft-collinear effective theory, the leading-log radiative electroweak corrections are written in a closed and analytical form for the hadronic cross section of Higgs production through vector boson fusion, qq->qqH, one of the most promising channels ... More
Light Higgs bosons from a strongly interacting Higgs sectorMay 02 2001The mass and the decay width of a Higgs boson in the minimal standard model are evaluated by a variational method in the limit of strong self-coupling interaction. The non-perturbative technique provides an interpolation scheme between strong-coupling ... More
The Stanely-Féray-Śniady formula for the generalized characters of the Symmetric GroupMar 05 2011We show that the explicit formula of Stanley-F\'eray-\'Sniady for the characters of the symmetric group have a natural extension to the generalized characters. These are the spherical functions of the unbalanced Gel'fand pair $(S_n\times S_{n-1},\text{diag}S_{n-1})$. ... More
Optimal transport with branching distance costs and the obstacle problemMar 14 2011Sep 28 2012We address the Monge problem in metric spaces with a geodesic distance: (X, d) is a Polish space and dN is a geodesic Borel distance which makes (X,dN) a possibly branching geodesic space. We show that under some assumptions on the transference plan we ... More
Frequently Asked Questions on the Luminosity--Temperature relation in Groups and ClustersJan 29 2002Jan 31 2002Efforts to understand the deviation of the L--T relation from a simple scaling law valid for clusters and groups have triggered a number of interesting studies on the subject. Techniques and approaches differ widely but most works agree on the important ... More
The Abundance Scatter in M33 from HII Regions: Is There Any Evidence for Azimuthal Metallicity Variations?Feb 01 2011Optical spectra of 25 H II regions in the inner two kpc of the M33 disk have been obtained with the GMOS spectrograph at the Gemini North telescope. The oxygen abundance gradient measured from the detection of the [O III]4363 auroral line displays a scatter ... More
The massive star IMF at high metallicityAug 28 2004The question of the variation of the upper IMF at high metallicity is briefly reviewed. I show recent results suggesting a revision in the definition of `high metallicity' in extragalactic H II regions. I present preliminary results concerning constraints ... More
Blue Supergiants as a Tool for Extragalactic Distances - Empirical DiagnosticsJan 10 2003Blue supergiant stars can be exceptionally bright objects in the optical, making them prime targets for the determination of extragalactic distances. I describe how their photometric and spectroscopic properties can be calibrated to provide a measurement ... More
Gravity coupling from micro-black holesJul 17 1999Jul 31 2000Recently much work has been done in lowering the Planck threshold of quantum gravitational effects (sub-millimeter dimension(s), Horava-Witten fifth dimension, strings or branes low energy effects, etc.). Working in the framework of 4-dim gravity, with ... More
Black Hole Entropy: a spacetime foam approachJun 11 1997The spacetime foam structure is reviewed briefly (topogical fluctuations and virtual black hole possibility; equation of state of the foam). A model of space foam at the surface of the event horizon is introduced. The model is applied to the calculus ... More
Variations of the Initial Mass Function in Semi-Analytical modelsMay 29 2014Deviations from a universal, MW-like, Stellar Initial Mass Function (IMF) have been reported for distant galaxies, although the physical reason behind the observed variations is still matter of ongoing debate. In this paper, we present an exploratory ... More
Calculation of the non-perturbative strong coupling from first principlesFeb 11 2019The success of the screened massive expansion is investigated in the framework of a screened momentum-subtraction scheme for the running of the strong coupling in pure Yang-Mills theory. By the exact Slavnov-Taylor and Nielsen identities, a very predictive ... More
A variational formulation for relativistic mechanics based on Riemannian geometry and its application to the quantum mechanics contextDec 07 2018This article develops a variational formulation of relativistic nature applicable to the quantum mechanics context. The main results are obtained through basic concepts on Riemannian geometry. Standards definitions such as vector fields and connection ... More
Boundedness of Fourier integral operators on Fourier Lebesgue spaces and affine fibrationsMay 27 2008We carry on the study of Fourier integral operators of H{\"o}rmander's type acting on the spaces $(\mathcal{F}L^p)_{comp}$, $1\leq p\leq\infty$, of compactly supported distributions whose Fourier transform is in $L^p$. We show that the sharp loss of derivatives ... More
Global splittings and super Harish-Chandra pairs for affine supergroupsAug 02 2013Sep 17 2015This paper dwells upon two aspects of affine supergroup theory, investigating the links among them. First, I discuss the "splitting" properties of affine supergroups, i.e. special kinds of factorizations they may admit - either globally, or pointwise. ... More
Geometrical Meaning of R-matrix Action for Quantum Groups at Roots of 1Apr 12 1996May 08 2017The present work splits in two parts: first, we perform a straightforward generalization of results from [Re], proving autoquasitriangularity of quantum groups $ U_q(\frak{g}) $ and their unrestricted specializations at roots of 1, in particular the function ... More
On central fields in the calculus of variationsSep 17 2018This article develops sufficient conditions of local optimality for the scalar and vectorial cases of the calculus of variations. The results are established through the construction of stationary fields which keep invariant what we define as the generalized ... More
Massless scalar free Field in 1+1 dimensions I: Weyl algebras Products and Superselection SectorsNov 21 2005Jul 25 2009This is the first of two papers on the superselection sectors of the conformal model in the title, in a time zero formulation. A classification of the sectors of the net of observables as restrictions of solitonic (twisted) and non-solitonic (untwisted) ... More
Nonnegatively curved 5-manifolds with non-abelian symmetryDec 20 2012We classify compact simply-connected 5-dimensional manifolds which admit a metric of nonnegative curvature with a connected non-abelian group acting by isometries. We show that they are diffeomorphic to either S^5, S^3 x S^2, the nontrivial S^3-bundle ... More
The global quantum duality principle: a survey through examplesSep 16 2011Let R be a 1-dimensional integral domain, let h (non-zero) be a prime element, and let \HA be the category of torsionless Hopf algebras over R. We call H in \HA a "quantized function algebra" (=QFA), resp. "quantized restricted universal enveloping algebras" ... More
On a mathematical relation between the Eigen model and the asexual Wright-Fisher modelFeb 01 2011We show that the Eigen model and the asexual Wright-Fisher model can be obtained as different limit cases of a unique stochastic model. This derivation makes clear which are the exact differences between these two models. The two key concepts introduced ... More
Massless scalar free Field in 1+1 dimensions, II: Net Cohomology and Completeness of Superselection SectorsNov 28 2008May 06 2010As an application of Roberts' cohomology (net cohomology), we prove the completeness of the DHR sectors of the local observables of the model in the title, detailed in [8]. This result is achieved via the triviality of the net 1-cohomology, with values ... More
Dipole-dipole interactions in protein-protein complexes: a quantum mechanical study of the ubiquitin-Dsk2 complexAug 14 2013Quantum mechanical calculations are performed on the proteins that constitute the ubiquitin-Dsk2 complex whose atomic structure has been experimentally determined by NMR spectroscopy (PDB id 1WR1). The results indicate that the dipole moment vectors of ... More
Protein conformational dynamics and electronic structureAug 18 2013Quantum mechanical calculations are performed on 116 conformers of the protein ubiquitin (Lange et al., Science 2008, 320, 1471-1475). The results indicate that the heat of formation (HOF), dipole moment, energy of the frontier orbitals HOMO and LUMO, ... More
A factorization method for q-Racah polynomialsJan 10 2011Jul 14 2011We develop a factorization method for q-Racah polynomials. It is inspired to the approach to q-Hahn polynomials based on the q-Johnson scheme but we do not use association scheme theory nor Gel'fand pairs, but only manipolation of q-difference operators. ... More
FreeIMU: An Open Hardware Framework for Orientation and Motion SensingMar 20 2013Orientation and Motion Sensing are widely implemented on various consumer products, such as mobile phones, tablets and cameras as they enable immediate interaction with virtual information. The prototyping phase of any orientation and motion sensing capable ... More
Condensation of gauge interacting mass-less fermionsJan 28 2004A single mass-less fermionic field with an abelian U(1) gauge interaction (electrodynamics of a mass-less Dirac fermion) is studied by a variational method. Even without the insertion of any extra interaction the vacuum is shown to be unstable towards ... More
A Truly Minimal Left-Right Symmetric Extension of the Standard ModelJul 25 2003By invoking the existence of a general custodial O(2) symmetry, a minimal Left-Right symmetric model based on the gauge group G=SU(2)L SU(2)R U(1)BL is shown to require the existence of only two physical Higgs bosons. The lighter Higgs is predicted to ... More
Low Dimensional Ordering on a Lattice ModelJan 08 1997A simple d-dimensional lattice model is proposed, incorporating some degree of frustration and thus capable of describing some aspects of molecular orientation in covalently bound molecular solids. For d=2 the model is shown to be equivalent to the standard ... More
The Monge problem in Wiener SpaceMar 14 2011Mar 24 2011We address the Monge problem in the abstract Wiener space and we give an existence result provided both marginal measures are absolutely continuous with respect to the infinite dimensional Gaussian measure {\gamma}.
Particle production in DIS off a shockwave in AdSDec 09 2009Sep 01 2010Within the AdS/CFT correspondence, the shockwave metric has been widely used as a gravity dual for a fast moving nucleus. Here we propose a picture for particle production in deep inelastic scattering off a shockwave with the projectile represented by ... More
Massive stars in the nuclei and arms of spiralsMay 09 2008Many of the properties of massive stars in external galaxies, such as chemical compositions, mass functions, and ionizing fluxes, can be derived from the study of the associated clouds of ionized gas. Moreover, the signatures of Wolf-Rayet stars are often ... More
A categorical semantic for the Typed Epsilon CalculusSep 08 2014We show that every boolean category satisfying AC provides a categorical semantic of the typed Epsilon calculus.
Incommensurability effects on dipolar bosons in optical latticesOct 29 2015We present a study that investigated a quantum dipolar gas in continuous space where a potential lattice was imposed. Employing exact quantum Monte Carlo techniques, we analysed the ground state properties of the scrutinised system, varying the lattice ... More
A quantum-like view to a generalized two players gameMar 03 2015This paper consider the possibility of using some quantum tools in decision making strategies. In particular, we consider here a dynamical open quantum system helping two players, $\G_1$ and $\G_2$, to take their decisions in a specific context. We see ... More
Perturbation theory of non-perturbative QCDJul 20 2015Perturbation theory is shown to be working in the IR limit of pure SU(3) Yang-Mills theory in Landau gauge by an unconventional setting of the perturbative expansion. A dynamical mass is predicted for the gluon and the lattice data are reproduced fairly ... More
A PBW basis for Lusztig's form of untwisted affine quantum groupsJun 17 1997Apr 03 1998Let g be an untwisted affine Kac-Moody algebra over the field K, and let U_q(g) be the associated quantum enveloping algebra; let \hat{U}_q(g) be the Lusztig's integer form of U_q(g), generated by q-divided powers of Chevalley generators over a suitable ... More
The very-extended tromboneJan 11 2010Mar 24 2010Starting from the very-extended Kac-Moody algebra $E_{11}$, we consider the algebra $E_{11,D}^{local}$, obtained by adding to the non-negative level $E_{11}$ generators the $D$-dimensional momentum operator and an infinite set of additional generators ... More
Vocal Access to a Newspaper Archive: Design Issues and Preliminary InvestigationDec 10 1998This paper presents the design and the current prototype implementation of an interactive vocal Information Retrieval system that can be used to access articles of a large newspaper archive using a telephone. The results of preliminary investigation into ... More
Sheafification functors and Tannaka's reconstructionSep 14 2014We introduce "sheafification" functors from categories of (lax monoidal) linear functors to cat- egories of quasi-coherent sheaves (of algebras) of stacks. They generalize the homogeneous sheafification of graded modules for projective schemes and have ... More
A duality principle for a semi-linear model in micro-magnetismDec 13 2017This article develops a duality principle for a semi-linear model in micro-magnetism. The results are obtained through standard tools of convex analysis and the Legendre transform concept. We emphasize the dual variational formulation presented is concave ... More
A duality principle for non-linear elasticityDec 07 2017Dec 03 2018This article develops a duality principle for non-linear elasticity. The results are obtained through standard tools of convex analysis and the Legendre transform concept. We emphasize the dual variational formulation is concave. Moreover, sufficient ... More
Global existence results and duality for non-linear models of plates and shellsDec 05 2017Nov 24 2018In this article firstly we develop a new proof for global existence of minimizers for the Kirchhoff-Love plate model. We also present a duality principle and relating sufficient optimality conditions for such a variational plate model. In a second step, ... More
Quantization of Poisson groups -- IIApr 10 1996May 08 2017Let $ G^\tau $ be a connected simply connected semisimple algebraic group, endowed with generalized Sklyanin-Drinfeld structure of Poisson group; let $ H^\tau $ be its dual Poisson group. By means of Drinfeld's double construction and dualization via ... More
Modified scattering for the Boson Star EquationAug 29 2013We consider the question of scattering for the boson star equation in three space dimensions. This is a semi-relativistic Klein-Gordon equation with a cubic nonlinearity of Hartree type. We combine weighted estimates, obtained by exploiting a special ... More
The global quantum duality principle: theory, examples, applicationsAug 02 2001Oct 04 2012The "quantum duality principle" states that a quantisation of a Lie bialgebra provides also a quantisation of the dual formal Poisson group and, conversely, a quantisation of a formal Poisson group yields a quantisation of the dual Lie bialgebra as well. ... More
The global quantum duality principleDec 22 1999May 04 2017Let R be an integral domain, let a non-zero h in R be such that k := R/hR is a field, and let HA be the category of torsionless (or flat) Hopf algebras over R. We call H in HA a "quantized function algebra" (=QFA), resp. "quantized restricted universal ... More
Incorporating fermions in the Gaussian Effective Potential: the Higgs-Top SectorAug 17 2012Oct 10 2012The Higgs-Top model is studied by a non-perturbative variational extension of the Gaussian Effective Potential that incorporates fermions. In the limit of a very strong Yukawa coupling the one-loop result is shown to follow a single-parameter scaling ... More
Grand unification in the minimal left-right symmetric extension of the standard modelAug 17 2012The simplest minimal left-right symmetric extension of the standard model is studied in the high energy limit, and some consequences of the grand unification hypothesis are explored assuming that the parity breaking scale is the only relevant energy between ... More
A note on a residual subset of Lipschitz functions on metric spacesJun 20 2013Let (X, d) be a quasi-convex, complete and separable metric space with reference probability measure m. We prove that the set of of real valued Lipschitz function with non zero point-wise Lipschitz constant m-almost everywhere is residual, and hence dense, ... More
Revisiting the abundance gradient in the maser host galaxy NGC 4258Jan 01 2011New spectroscopic observations of 36 HII regions in NGC 4258 obtained with the Gemini telescope are combined with existing data from the literature to measure the radial oxygen abundance gradient in this galaxy. The [OIII]4363 auroral line was detected ... More
The oxygen abundance in the inner HII regions of M101. Implications for the calibration of strong-line metallicity indicatorsOct 23 2006I present deep spectroscopy of four HII regions in the inner, metal-rich zone of the spiral galaxy M101 obtained with the LRIS spectrograph at the Keck telescope. From the analysis of the collisionally excited lines in two of the target HII regions, H1013 ... More
Some Heuristic Semiclassical Derivations of the Planck Length, the Hawking Effect and the Unruh EffectJun 09 2002The formulae for Planck length, Hawking temperature and Unruh-Davies temperature are derived by using only laws of classical physics together with the Heisenberg principle. Besides, it is shown how the Hawking relation can be deduced from the Unruh relation ... More
Generalized Uncertainty Principle in Quantum Gravity from Micro-Black Hole Gedanken ExperimentApr 05 1999We review versions of the Generalized Uncertainty Principle (GUP) obtained in string theory and in gedanken experiments carried out in Quantum Gravity. We show how a GUP can be derived from a measure gedanken experiment involving micro-black holes at ... More
Glimpses on the micro black hole Planck phaseSep 10 2008Mass thresholds, lifetimes, entropy and heat capacity for micro black holes close to their late Schwarzschild phase are computed using two different generalized uncertainty principles, in the framework of models with extra spatial dimensions. Emissions ... More
A quantum-like description of the planetary systemsJul 11 2005Nov 25 2007The Titius-Bode law for planetary distances is reviewed. A model describing the basic features of this rule in the "quantum-like" language of a wave equation is proposed. Some considerations about the 't Hooft idea on the quantum behaviour of deterministic ... More
Second order gluon polarization for SU(N) theory in linear covariant gaugeJul 01 2015The gluon polarization functional is evaluated for a generic linear covariant gauge and for any space dimension in pure Yang-Mills SU(N) theory up to second order in a generalized perturbation theory, where the zeroth order action is freely chosen and ... More
Copula based hierarchical risk aggregation - Tree dependent sampling and the space of mild tree dependenceJun 11 2015Jun 19 2015The ability to adequately model risks is crucial for insurance companies. The method of "Copula-based hierarchical risk aggregation" by Arbenz et al. offers a flexible way in doing so and has attracted much attention recently. We briefly introduce the ... More
On the time slicing approximation of Feynman path integrals for non-smooth potentialsJun 03 2015We consider the time slicing approximations of Feynman path integrals, constructed via piecewice classical paths. A detailed study of the convergence in the norm operator topology, in the space $\mathcal{B}(L^2(\mathbb{R}^d))$ of bounded operators on ... More
On the distribution of stellar remnants around massive black holes: slow mass segregation, star cluster inspirals and correlated orbitsFeb 20 2014Aug 29 2014We study the long term dynamical evolution of stellar mass black holes (BHs) at the Galactic center (GC) and put constraints on their number and central mass distribution. Models of the GC are considered that have not yet achieved a steady state under ... More
Introduction to quantum information theory and outline of two applications to physics: the black hole information paradox and the renormalization group information flowJul 03 2015Jul 06 2015This review paper is intended for scholars with different backgrounds, possibly in only one of the subjects covered, and therefore little background knowledge is assumed. The first part is an introduction to classical and quantum information theory (CIT, ... More
Analytical study of Yang-Mills theory in the infrared from first principlesNov 03 2015Mar 29 2016Pure Yang-Mills SU(N) theory is studied in the Landau gauge and four dimensional space. While leaving the original Lagrangian unmodified, a double perturbative expansion is devised, based on a massive free-particle propagator. In dimensional regularization, ... More
Consistent transformations of belief functionsJul 30 2014Consistent belief functions represent collections of coherent or non-contradictory pieces of evidence, but most of all they are the counterparts of consistent knowledge bases in belief calculus. The use of consistent transformations cs[.] in a reasoning ... More
On the operation of X-ray polarimeters with a large field of viewDec 09 2013The measurement of the linear polarization is one of the hot topics of High Energy Astrophysics. Gas detectors based on photoelectric effect have paved the way for the design of sensitive instruments and mission proposals based on them have been presented ... More
Dispersion relations for unphysical particlesJun 12 2016Jun 30 2016Generalized dispersion relations are discussed for unphysical particles, e.g. confined degrees of freedom that are not present in the physical spectra but can give rise to observable bound states. While in general the propagator of the unphysical particles ... More
Analytic structure of QCD propagators in Minkowski spaceMay 24 2016Oct 05 2016Analytical functions for the propagators of QCD, including a set of chiral quarks, are derived by a one-loop massive expansion in the Landau gauge, deep in the infrared. By analytic continuation, the spectral functions are studied in Minkowski space, ... More
An introduction to integrable techniques for one-dimensional quantum systemsSep 07 2016Sep 20 2016This monograph introduces the reader to basic notions of integrable techniques for one-dimensional quantum systems. In a pedagogical way, a few examples of exactly solvable models are worked out to go from the coordinate approach to the Algebraic Bethe ... More
The R-matrix action of untwisted affine quantum groups at roots of 1May 04 1998Sep 13 1999Let $\hat{\frak g}$ be an untwisted affine Kac-Moody algebra. The quantum group $U_h(\hat{\frak g})$ (over $C[[h]]$) is known to be a quasitriangular Hopf algebra: in particular, it has a universal R-matrix, which yields an R-matrix for each pair of representations ... More
Quantum function algebras as quantum enveloping algebrasJan 10 1997Nov 07 1997Inspired by a result in the same author's previous work q-alg/9604009, we locate two $ k[q,q^{-1}] $--integer forms of $ F_q[SL(n+1)] $, along with a presentation by generators and relations, and prove that for $ q=1 $ they specialize to $ U({\frak h}) ... More
Dark photon searches using displaced vertices at low energy e+e- collidersOct 30 2013Jan 31 2014The existence of a new, photon-like, massive particle, the gamma' or dark photon, is postulated in several extensions of the Standard Model. These models are often advocated to explain some recent puzzling astrophysical observations, as well as to solve ... More
Robust Three-axis Attitude Stabilization for Inertial Pointing Spacecraft Using MagnetorquersNov 11 2014In this work feedback control laws are designed for achieving three-axis attitude stabilization of inertial pointing spacecraft using only magnetic torquers. The designs are based on an almost periodic model of geomagnetic field along the spacecraft's ... More
The Higgs puzzle: experiment and theoryDec 10 2001The present experimental and theoretical knowledge of the physics of electroweak symmetry breaking is reviewed. Data still favor a light Higgs boson, of a kind that can be comfortably accommodated in the Standard Model or in its Minimal Supersymmetric ... More
The SUSY WorldJul 19 1993Summary Talk of the Workshop `Properties of SUSY particles' Erice, September 28 -- October 4, 1992.
Lie supergroups vs. super Harish-Chandra pairs: a new equivalenceSep 09 2016This paper presents a new contribution to the study of Lie supergroups - of real smooth, real analytic or complex holomorphic type - by means of super Harish-Chandra pairs. Namely, one knows that there exists a natural functor \Phi\ from Lie supergroups ... More
Cooling a vibrational mode coupled to a molecular single-electron transistorJan 15 2009We consider a molecular single electron transistor coupled to a vibrational mode. For some values of the bias and gate voltage transport is possible only by absorption of one ore more phonons. The system acts then as a cooler for the mechanical mode at ... More
Open heavy-flavour measurements with ALICE at the LHCSep 18 2018Heavy quarks are produced in the early stages of ultra-relativistic heavy-ion collisions, and their number is preserved throughout the subsequent evolution of the system. Therefore, they constitute ideal probes for characterising the Quark--Gluon Plasma ... More
On duality principles for non-convex variational models applied to a Ginzburg-Landau type equationDec 04 2017Jan 17 2018This article develops a duality principle applicable to a large class of variational problems. Firstly, we apply the results to a Ginzburg-Landau type model. In a second step, we develop another duality principle and related primal dual variational formulation ... More
Algebraic supergroups of Cartan typeSep 03 2011Oct 29 2015I present a construction of connected affine algebraic supergroups G_V associated with simple Lie superalgebras g of Cartan type and with g-modules V. Conversely, I prove that every connected affine algebraic supergroup whose tangent Lie superalgebra ... More