Results for "Antonios Garas"

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The Rise and Fall of R&D NetworksApr 12 2013Mar 17 2016Drawing on a large database of publicly announced R&D alliances, we empirically investigate the evolution of R&D networks and the process of alliance formation in several manufacturing sectors over a 24-year period (1986-2009). Our goal is to empirically ... More
A network approach for the scientific collaboration in the European Framework ProgramsOct 07 2008We construct the networks of collaboration between partners for projects carried out with the support of European Commission Framework Programs FP5 and FP6. We analyze in detail these networks, not only in terms of total number of projects, but also for ... More
Filtering of complex systems using overlapping tree networksDec 17 2008We introduce a technique that is capable to filter out information from complex systems, by mapping them to networks, and extracting a subgraph with the strongest links. This idea is based on the Minimum Spanning Tree, and it can be applied to sets of ... More
The role of networks in firms' multi-characteristics competition and market-share inequalityJan 21 2016We develop a location analysis spatial model of firms' competition in multi-characteristics space, where consumers' opinions about the firms' products are distributed on multilayered networks. Firms do not compete on price but only on location upon the ... More
All Simple Venn Diagrams are HamiltonianApr 24 2015An $n$-Venn diagram is a certain collection of $n$ simple closed curves in the plane. They can be regarded as graphs where the points of intersection are vertices and the curve segments between points of intersection are edges. Every $n$-Venn diagram ... More
The development of nations conditions the disease spaceMar 22 2019Using the economic complexity methodology on data for disease prevalence in 195 countries during the period of 1990-2016, we propose two new metrics for quantifying the relatedness between diseases, or the `disease space' of countries. With these metrics, ... More
Control contribution identifies top driver nodes in complex networksJun 11 2019We propose a new measure to quantify the impact of a node $i$ in controlling a directed network. This measure, called `control contribution' $\mathcal{C}_{i}$, combines the probability for node $i$ to appear in a set of driver nodes and the probability ... More
The structural role of weak and strong links in a financial market networkMay 16 2008We investigate the properties of correlation based networks originating from economic complex systems, such as the network of stocks traded at the New York Stock Exchange (NYSE). The weaker links (low correlation) of the system are found to contribute ... More
A k-shell decomposition method for weighted networksMay 16 2012Aug 27 2012We present a generalized method for calculating the k-shell structure of weighted networks. The method takes into account both the weight and the degree of a network, in such a way that in the absence of weights we resume the shell structure obtained ... More
The relation between migration and FDI in the OECD from a complex network perspectiveJan 26 2017We explore the relationship between human migration and OECD's foreign direct investment (FDI) using a gravity equation enriched with variables that account for complex-network effects. Based on a panel data analysis, we find a strong positive correlation ... More
The spatial component of R&D networksSep 28 2015We study the role of geography in R&D networks by means of a quantitative, micro-geographic approach. Using a large database that covers international R&D collaborations from 1984 to 2009, we localize each actor precisely in space through its latitude ... More
The network structure of city-firm relationsDec 09 2015How are economic activities linked to geographic locations? To answer this question, we use a data-driven approach that builds on the information about location, ownership and economic activities of the world's 3,000 largest firms and their almost one ... More
Selection rules in alliance formation: strategic decisions or abundance of choice?Mar 13 2014Mar 14 2014We study how firms select partners using a large database of publicly announced R&D alliances over a period of 25 years. We identify, for the first time, two distinct behavioral strategies of firms in forming these alliances. By reconstructing and analysing ... More
The Network of Counterparty Risk: Analysing Correlations in OTC DerivativesJun 15 2015Sep 15 2015Counterparty risk denotes the risk that a party defaults in a bilateral contract. This risk not only depends on the two parties involved, but also on the risk from various other contracts each of these parties holds. In rather informal markets, such as ... More
Controllability of temporal networks: An analysis using higher-order networksJan 23 2017Apr 25 2017The control of complex networks is a significant challenge, especially when the network topology of the system to be controlled is dynamic. Addressing this challenge, here we introduce a novel approach which allows exploring the controllability of temporal ... More
Positive words carry less information than negative wordsOct 18 2011May 27 2012We show that the frequency of word use is not only determined by the word length \cite{Zipf1935} and the average information content \cite{Piantadosi2011}, but also by its emotional content. We have analyzed three established lexica of affective word ... More
Higher-Order Aggregate Networks in the Analysis of Temporal Networks: Path structures and centralitiesAug 26 2015Recent research on temporal networks has highlighted the limitations of a static network perspective for our understanding of complex systems with dynamic topologies. In particular, recent works have shown that i) the specific order in which links occur ... More
How big is too big? Critical Shocks for Systemic Failure CascadesSep 05 2012Apr 15 2013External or internal shocks may lead to the collapse of a system consisting of many agents. If the shock hits only one agent initially and causes it to fail, this can induce a cascade of failures among neighoring agents. Several critical constellations ... More
The Rise and Fall of R&D NetworksApr 12 2013Aug 05 2017Drawing on a large database of publicly announced R&D alliances, we empirically investigate the evolution of R&D networks and the process of alliance formation in several manufacturing sectors over a 24-year period (1986-2009). Our goal is to empirically ... More
Predicting Scientific Success Based on Coauthorship NetworksFeb 28 2014We address the question to what extent the success of scientific articles is due to social influence. Analyzing a data set of over 100000 publications from the field of Computer Science, we study how centrality in the coauthorship network differs between ... More
The Rise and Fall of R&D NetworksApr 12 2013Oct 30 2016Drawing on a large database of publicly announced R&D alliances, we empirically investigate the evolution of R&D networks and the process of alliance formation in several manufacturing sectors over a 24-year period (1986-2009). Our goal is to empirically ... More
Systemic risk in multiplex networks with asymmetric coupling and threshold feedbackJun 22 2015We study cascades on a two-layer multiplex network, with asymmetric feedback that depends on the coupling strength between the layers. Based on an analytical branching process approximation, we calculate the systemic risk measured by the final fraction ... More
Worldwide spreading of economic crisisAug 23 2010We model the spreading of a crisis by constructing a global economic network and applying the Susceptible-Infected-Recovered (SIR) epidemic model with a variable probability of infection. The probability of infection depends on the strength of economic ... More
An ensemble perspective on multi-layer networksJul 01 2015We study properties of multi-layered, interconnected networks from an ensemble perspective, i.e. we analyze ensembles of multi-layer networks that share similar aggregate characteristics. Using a diffusive process that evolves on a multi-layer network, ... More
Emotional persistence in online chatting communitiesMay 11 2012How do users behave in online chatrooms, where they instantaneously read and write posts? We analyzed about 2.5 million posts covering various topics in Internet relay channels, and found that user activity patterns follow known power-law and stretched ... More
Betweenness Preference: Quantifying Correlations in the Topological Dynamics of Temporal NetworksAug 02 2012May 02 2013We study correlations in temporal networks and introduce the notion of betweenness preference. It allows to quantify to what extent paths, existing in time-aggregated representations of temporal networks, are actually realizable based on the sequence ... More
Causality-Driven Slow-Down and Speed-Up of Diffusion in Non-Markovian Temporal NetworksJul 15 2013Aug 26 2015Recent research has highlighted limitations of studying complex systems with time-varying topologies from the perspective of static, time-aggregated networks. Non-Markovian characteristics resulting from the ordering of interactions in temporal networks ... More
The QCD potential at O(1/m^2): Complete spin-dependent and spin-independent resultSep 12 2000Apr 11 2001Within an effective field theory framework, we obtain an expression, with O(1/m^2) accuracy, for the energies of the gluonic excitations between heavy quarks, which holds beyond perturbation theory. For the singlet heavy quark--antiquark energy, in particular, ... More
Cosmic $ΔB$ from Lepton Violating Interactions at the Electroweak Phase TransitionJun 05 1992We propose a new mechanism for late cosmological baryon asymmetry in models with first order electroweak phase transition. Lepton asymmetry arises through the decay of particles produced out of equilbrium in bubble collisions and is converted into baryon ... More
Existence and convexity of solutions of the fractional heat equationJun 01 2016Aug 22 2017We prove that the initial-value problem for the fractional heat equation admits a solution provided that the (possibly unbounded) initial datum has a conveniently moderate growth at infinity. Under the same growth condition we also prove that the solution ... More
Construction of the pseudo Riemannian geometry on the base of the Berwald-Moor geometrySep 05 2006The space of the associative commutative hyper complex numbers, H_4, is a 4-dimensional metric Finsler space with the Berwald-Moor metric. It provides the possibility to construct the tensor fields on the base of the analytical functions of the H_4 variable ... More
Topological invariants of O'Grady's six dimensional irreducible symplectic varietyJun 02 2004Aug 08 2004We study O'Grady examples of irreducible symplectic varieties: we establish that both of them can be deformed into lagrangian fibrations. We analyse in detail the topology of the six dimensional example: in particular we compute its Euler characteristic ... More
Distributed Space-Time Coding of Over-the-Air Superimposed Packets in Wireless NetworksMar 14 2013In this paper we propose a new cooperative packet transmission scheme that allows independent sources to superimpose over-the-air their packet transmissions. Relay nodes are used and cooperative diversity is combined with distributed space-time block ... More
General Covariance, Diffeomorphism Invariance, and Background Independence in 5 DimensionsOct 04 2014Apr 10 2015The paper considers the "GR-desideratum", that is, the way general relativity implements general covariance, diffeomorphism invariance, and background independence. Two cases are discussed where $5$-dimensional generalizations of general relativity run ... More
Darboux polynomial matrices: the classical Massive Thirring Model as study caseNov 28 2014One way of constructing explicit expressions of solutions of integrable systems of Partial Differential Equations (PDEs) goes via the Darboux method. This requires the construction of Darboux matrices. Here we introduce a novel algorithm to obtain such ... More
Plenty of Morse functions by perturbing with sums of squaresNov 16 2011Given a smooth function f on R^n and a submanifold M, we prove that the set of diagonal quadratic forms q such that the restriction of f+q to M is Morse is a dense set (in the n-dimensional space of diagonal quadratic forms). The standard transversality ... More
Convex pencils of real quadratic formsJun 23 2011Sep 06 2012We study the topology of the set X of the solutions of a system of two quadratic inequalities in the real projective space RP^n (e.g. X is the intersection of two real quadrics). We give explicit formulae for its Betti numbers and for those of its double ... More
Inflation and the Theory of Cosmological PerturbationsOct 10 2002These lectures provide a pedagogical introduction to inflation and the theory of cosmological perturbations generated during inflation which are thought to be the origin of structure in the universe.
The More Relaxed Supersymmetric Electroweak BaryogenesisMar 15 1998We reanalyze the issue of generation of the baryon asymmetry at the electroweak phase transition in the MSSM and compute the baryon asymmetry assuming the presence of non-trivial CP-violating phases in the parameters associated with the left-right stop ... More
Effective field theories for baryons with two- and three-heavy quarksAug 26 2010Oct 28 2010Baryons made of two or three heavy quarks can be described in the modern language of non-relativistic effective field theories. These, besides allowing a rigorous treatment of the systems, provide new insight in the nature of the three-body interaction ... More
Non-relativistic bound states: the long way back from the Bethe-Salpeter to the Schroedinger equationFeb 19 2009Apr 06 2009I review, in a personal perspective, the history of the theory of non-relativistic bound states in QED and QCD from the Bethe-Salpeter equation to the construction of effective field theories.
Heavy quarkonium decays and transitions in the language of effective field theoriesDec 30 2005Heavy quarkonium decays and transitions are discussed in the framework of non-relativistic effective field theories. Emphasis is put on the matching procedure in the non-perturbative regime. Some exact results valid for the magnetic dipole couplings are ... More
The QCD potentialSep 21 2007After reviewing the definition of the heavy quark-antiquark potential in pNRQCD, we discuss recent advances in the calculation.
Asymmetric random walks in a discrete spacetime as a model for quantum mechanicsDec 20 2013Jan 25 2015This paper presents a simple model that mimics quantum mechanics (QM) results in terms of probability fields of free particles subject to self-interference, without using Schr\"{o}dinger equation or wavefunctions. Unlike the standard QM picture, the proposed ... More
Dynamics and (de)localization in a one-dimensional tight-binding chainJul 18 2006A simple tight-binding model is used to illustrate how the time dependence of a state vector can be obtained from all the eigenvalues and eigenvectors of the Hamiltonian. The behavior of the eigenvalues and eigenvectors is studied for various parameters ... More
Energies of sp2 carbon shapes with pentagonal disclinations and elasticity theoryMar 28 2006Jun 26 2006Energies of a certain class of fullerene molecules (elongated, contracted, and regular icosahedral fullerenes) are numerically calculated using a microscopic description of carbon-carbon bonding. It is shown how these results can be interpreted and comprehended ... More
Adsorption of He atoms in external grooves of single wall carbon nanotube bundlesNov 15 2002I calculate the quantum states for He atom in the potential of an external groove of the single wall carbon nanotube bundle. The calculated ground state energy is found to be in fair agreement with the experimental estimate which suggests that the outer ... More
Icosadeltahedral geometry of fullerenes, viruses and geodesic domesNov 22 2007I discuss the symmetry of fullerenes, viruses and geodesic domes within a unified framework of icosadeltahedral representation of these objects. The icosadeltahedral symmetry is explained in details by examination of all of these structures. Using Euler's ... More
A discrete spacetime model for quantum mechanicsJun 02 2015This paper presents a simple model that mimics quantum mechanics (QM) results in terms of probability fields of free particles subject to self-interference, without using Schroedinger equation or complex wavefunctions. Unlike the standard QM picture, ... More
ICHEP 2014 Summary: Theory Status after the First LHC RunMay 07 2015Jun 08 2015A brief overview of the main highlights discussed at ICHEP 2014 is presented. The experimental data confirm that the scalar boson discovered at the LHC couples to other particles as predicted in the Standard Model. This constitutes a great success of ... More
Quantifying the dynamical complexity of time seriesOct 19 2016A powerful tool is developed for the characterization of chaotic signals. The approach is based on the symbolic encoding of time series (according to their ordinal patterns) combined with the ensuing characterization of the corresponding cylinder sets. ... More
Spectroscopic investigations of phonons in epitaxial grapheneJan 04 2016The interaction of graphene with metallic substrates reveals phenomena and properties of great relevance for applications in nanotechnology. In this review, the vibrational characterization by means of various inelastic scattering spectroscopies are surveyed ... More
Can Bohmian Mechanics Be Made Background Independent?Sep 02 2015The paper presents an inquiry into the question regarding the compatibility of Bohmian mechanics, intended as a non-local theory of moving point-like particles, with background independence. This issue is worth being investigated because, if the Bohmian ... More
Proper holomorphic Legendrian curves in $SL_2(\mathbb{C})$Nov 02 2016In this paper we prove that every open Riemann surface properly embeds in the Special Linear group $SL_2(\mathbb{C})$ as a holomorphic Legendrian curve, where $SL_2(\mathbb{C})$ is endowed with its standard contact structure. As a consequence, we derive ... More
The number of weakly compact sets which generate a Banach spaceFeb 28 2009We consider the cardinal invariant CG(X) of the minimal number of weakly compact subsets which generate a Banach space X. We study the behavior of this index when passing to subspaces, its relation with the Lindelof number in the weak topology and other ... More
k-Colorability is Graph Automaton RecognizableJan 21 2014Automata operating on general graphs have been introduced by virtue of graphoids. In this paper we construct a graph automaton that recognizes $k$-colorable graphs.
A Topological Approach to Spectral ClusteringJun 08 2015We propose a clustering algorithm which, for input, takes data assumed to be sampled from a uniform distribution supported on a metric space $X$, and outputs a clustering of the data based on a topological estimate of the connected components of $X$. ... More
Lagrangian blow-ups, blow-downs, and applications to real packingDec 05 2010Dec 07 2012Given a symplectic manifold (M, {\omega}) and a Lagrangian submanifold L, we construct versions of the symplectic blow-up and blow-down which are defined relative to L. Furthermore, we show that if M admits an anti-symplectic involution {\phi} and we ... More
A Local-Realistic Model of Quantum Mechanics Based on a Discrete Spacetime (Extended version)Dec 08 2017This paper presents a realistic, stochastic, and local model that reproduces nonrelativistic quantum mechanics (QM) results without using its mathematical formulation. The proposed model only uses integer-valued quantities and operations on probabilities, ... More
A fixed point for the jump operator on structuresJun 05 2011Assuming that $0^#$ exists, we prove that there is a structure that can effectively interpret its own jump. In particular, we get a structure $\mathcal A$ such that \[ Sp({\mathcal A}) = \{{\bf x}':{\bf x}\in Sp ({\mathcal A})\}, \] where $Sp ({\mathcal ... More
The Aleph-zero or zero dichotomyApr 18 2008Nov 23 2009This paper proves the existence of a dichotomy which being formally derived from the topological successiveness of w-order leads to the same absurdity of Zeno's Dichotomy II. It also derives a contradictory result from the first Zeno's Dichotomy.
SuperswappingApr 18 2008Jan 27 2012Supertask theory is used here to prove a contradictory result which involves the consistency of w-order and the Axiom of Infinity.
Leptons and QCDDec 12 2014Three important QCD-related aspects of the $\tau$ and $\mu$ dynamics are reviewed: the determination of the strong coupling from the hadronic tau decay width, leading to the updated value $\alpha_s(m_\tau^2) = 0.331 \pm 0.013$; the measurement of $|V_{us}|$ ... More
Regular polyhedra in the 3-torusApr 21 2016In this paper we discuss the classification rank $3$ lattices preserved by finite orthogonal groups of isometries and derive from it the classification of regular polyhedra in the $3$-dimensional torus. This classification is highly related to the classification ... More
Stone-type representations and dualities for varieties of bisemilatticesMar 18 2018In this article we will focus our attention on the variety of distributive bisemilattices and some linguistic expansions thereof: bounded, De Morgan, and involutive bisemilattices. After extending Balbes' representation theorem to bounded, De Morgan, ... More
Asymptotic cosmological solutions for string/brane gases with solitonic fluxesJan 13 2005We present new cosmological solutions for brane gases with solitonic fluxes that can dynamically explain the existence of three large spatial dimensions. This reasserts the importance of fluxes for understanding the full space of solutions in a potential ... More
Open Problems in Heavy Quarkonium PhysicsDec 22 2004Some recent progress and a personal selection of open problems in heavy quarkonium physics (spectroscopy, decay and production) inspired by the activity of the Quarkonium Working Group are reviewed.
Hodographic VorticesAug 08 2008Jul 10 2009Vortices are screw phase dislocations associated with helicoidal wave-fronts. In nonlinear optics, vortices arise as singular solutions to the phase-intensity equations of geometric optics. They exist for a general class of nonlinear response functions. ... More
Transfinite partitions of Jordan curvesAug 21 2006The w-asymmetry induced by transfinite partitions makes it impossible for Jordan curves to have an infinite length.
Classes of structures with no intermediate isomorphism problemsSep 16 2013We say that a theory $T$ is intermediate under effective reducibility if the isomorphism problems among its computable models is neither hyperarithmetic nor on top under effective reducibility. We prove that if an infinitary sentence $T$ is uniformly ... More
Hydrogen Line Observations of Cometary Spectra at 1420 MhzJun 10 2017In 2016, the Center for Planetary Science proposed a hypothesis arguing a comet and/or its hydrogen cloud were a strong candidate for the source of the Wow! Signal. From 27 November 2016 to 24 February 2017, the Center for Planetary Science conducted ... More
Experimental results on event shapes at hadron collidersMay 05 2017In this paper a review on event shapes at hadron colliders, mainly focused on experimental results, is presented. Measurements performed at the Tevatron and at the LHC, for the soft and hard regimes of QCD, are reviewed. The potential applications of ... More
Production of $π$/K/p from intermediate to high $p_{\rm T}$ in pp, p-Pb and Pb-Pb collisions measured by ALICEApr 16 2014In this work the results on the transverse momentum distributions ($\sim0.3<p_{\rm T}<15$ GeV/$c$) of charged pions, kaons and (anti)protons, measured in $\rm pp$ and $\rm Pb-Pb$ collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV and in $\rm p-Pb$ collisions ... More
Special systems through double points on an algebraic surfaceMay 03 2006Let S be a smooth algebraic surface satisfying the following property: H^i(\oc_S(C))=0 (i=1,2) for any irreducible and reduced curve C of S. The aim of this paper is to provide a characterization of special linear systems on S which are singular along ... More
Short- and long-baseline sterile neutrino phenomenologyMay 03 2017Several anomalies observed in short-baseline neutrino experiments indicate that the standard 3-flavor framework may be incomplete and point towards the existence of light sterile neutrinos. Here, we present a concise review of the status of the neutrino ... More
An estimate of theta_14 independent of the reactor antineutrino flux determinationsJan 20 2012Mar 08 2012In a previous paper [Phys. Rev. D 83, 113013 (2011)] we have shown that the solar sector data (solar and KamLAND) are sensitive to the parameter theta_14, encoding the admixture of the electron neutrino with a fourth (essentially) sterile mass eigenstate. ... More
Hint of non-standard dynamics in solar neutrino conversionJan 20 2011Apr 27 2011Motivated by the recent low-threshold measurements of the solar 8B neutrino spectrum performed by Borexino, Super-Kamiokande and the Sudbury Neutrino Observatory -- all now monitoring the transition regime between low-energy (vacuum-like) and high-energy ... More
Constraining hybrid inflation models with WMAP three-year resultsOct 03 2006Jan 11 2007We reconsider the original model of quadratic hybrid inflation in light of the WMAP three-year results and study the possibility of obtaining a spectral index of primordial density perturbations, $n_s$, smaller than one from this model. The original hybrid ... More
The elliptic Kirchhoff equation in $\R^N$ perturbed by a local nonlinearityJan 02 2010Apr 26 2011In this paper we present a very simple proof of the existence of at least one non trivial solution for a Kirchhoff type equation on $\RN$, for $N\ge 3$. In particular, in the first part of the paper we are interested in studying the existence of a positive ... More
A family of acyclic functorsJun 14 2007Nov 08 2007We determine a family of functors from a poset to abelian groups such that the higher direct limits vanish on them. This is done by first characterizing the projective functors. Then a spectral sequence arising from the grading of the poset is used. Also ... More
Overview of ALICE resultsJan 22 2015The ALICE detector was designed to study the physics of matter under extreme conditions of high energy density. Different results were reported by the experiment using data from the successful run I of the LHC. The goal of the present work is to present ... More
Some reflections on variational methods for partial differential inclusionsJan 21 2016We discuss the application of variational methods, based on non-smooth critical point theory, to a general class of partial differential inclusions.
CMC hypersurfaces of semi-Riemannian groupsSep 26 2012Jan 01 2014In this paper, we study the geometry of a connected oriented cmc Riemannian hypersurface $M$ of a semi-Riemannian group $G$ of Lie algebra $\mathfrak g$ and index 0 or 1. If $G$ is Riemannian and $M$ is compact and transversal to an element of $\mathfrak ... More
Categorification of tensor powers of the vector representation of $U_q(\mathfrak{gl}(1|1))$May 27 2013Jan 09 2015We consider the monoidal subcategory of finite dimensional representations of $U_q(\mathfrak{gl}(1|1))$ generated by the vector representation, and we provide a diagram calculus for the intertwining operators, which allows to compute explicitly the canonical ... More
Quantum field theory of axion-photon mixing and vacuum polarizationApr 25 2019We report on recent results obtained by analyzing axion--photon mixing in the framework of quantum field theory. We obtain corrections to the oscillation formulae and we reveal a new effect of the vacuum polarization due to the non-zero value of the vacuum ... More
Half-space theorems for properly immersed surfaces in $\mathbb{R}^3$ with prescribed mean curvatureJan 14 2019Motivated by the large ammount of results obtained for minimal and positive constant mean curvature surfaces in several ambient spaces, the aim of this paper is to obtain half-space theorems for properly immersed surfaces in $\mathbb{R}^3$ whose mean ... More
Tau-decay determination of the strong couplingNov 25 2018We review the current status of the determination of the strong coupling from tau decay. Using the most recent release of the ALEPH data, a very comprehensive phenomenological analysis has been performed, exploring all strategies previously considered ... More
On the Lie and Cartan Theory of Invariant Differential Systems, IIIMar 23 2017It is presently our aim to undertake the discussion, of the Parts I and II, on the infinitesimal level and outline as well the transition from infinitesimal to finite, the main reason for this being, of course, the well known fact that arguments and calculation ... More
A multiplicity result for the nonlinear Klein Gordon Maxwell equationsJul 04 2014Dec 13 2014In this paper we provide a new technique to find solutions to the Klein-Gordon-Maxwell system. The method, based on an iterative argument, permits to improve previous results where the reduction method was used. We also show how this device permits to ... More
A necessary and sufficient condition for minimum phase and implications for phase retrievalJun 15 2016Oct 02 2016We give a necessary and sufficient condition for a function $E(t)$ being of minimum phase, and hence for its phase being univocally determined by its intensity $|E(t)|^2$. This condition is based on the knowledge of $E(t)$ alone and not of its analytic ... More
An Introduction to Quantum Mechanics ... for those who dwell in the macroscopic worldJan 20 2012Feb 18 2016There is a huge number of excellent and comprehensive textbooks on quantum mechanics. They mainly differ for the approach, more or less oriented to the formalism rather than to the phenomenology, as well as for the topics covered. These lectures have ... More
The total Betti number of the intersection of three real quadricsNov 16 2011We prove that the total Betti number of the intersection X of three quadrics in RP^n is bounded by n(n+1). This bound improves the classical Barvinok's one which is at least of order three in n.
The Nature of the Local GroupOct 27 2003The Local Group provides an interesting and representative sample of galaxies in the rest of the Universe. The high accuracy with which many problems can be addressed in Local Group galaxies is of paramount importance for understanding galaxy formation ... More
Thermal Background Corrections to the Neutrino Electromagnetic Vertex in Models with Charged Scalar BosonsNov 24 1993We calculate the correction to the neutrino electromagnetic vertex due to background of electrons in a large class of models, as the supersymmetric model with explicit breaking of R-parity, where charged scalar bosons couple to leptons and which are able ... More
D-branes, String Cosmology and Large Extra DimensionsApr 29 1999D-branes are fundamental in all scenarios where there are large extra dimensions and the string scale is much smaller than the four-dimensional Planck mass. We show that this current picture leads to a new approach to string cosmology where inflation ... More
Supersymmetric electroweak baryogenesis, nonequilibrium field theory and quantum Boltzmann equationsDec 01 1997Dec 03 1997The closed time-path (CTP) formalism is a powerful Green's function formulation to describe nonequilibrium phenomena in field theory and it leads to a complete nonequilibrium quantum kinetic theory. In this paper we make use of the CTP formalism to write ... More
Inflation and the Nature of Supersymmetry BreakingJul 11 1997The scale at which supersymmetry is broken and the mechanism by which supersymmetry breaking is fed down to the observable sector has rich implications on the way Nature may have chosen to accomplish inflation. We discuss a simple model for slow rollover ... More
The Singlet Majoron Model with Hidden Scale InvarianceJan 13 1993We investigate an extension of the Singlet Majoron Model in which the breaking of dilatation symmetry by the mass parameters of the scalar potential is removed by means of a dilaton field. Starting from the one-loop renormalization group improved potential, ... More
Quarkonium dissociation in a thermal bathJan 26 2015In an effective field theory framework we review the two main mechanisms of quarkonium dissociation in a weakly coupled thermal bath.
Heavy Hadron SpectroscopyNov 24 2006I review recent theoretical advances in heavy hadron spectroscopy.