Results for "Stefano Nichele"

total 6905took 0.14s
Deep Reservoir Computing Using Cellular AutomataMar 08 2017Recurrent Neural Networks (RNNs) have been a prominent concept within artificial intelligence. They are inspired by Biological Neural Networks (BNNs) and provide an intuitive and abstract representation of how BNNs work. Derived from the more generic ... More
Towards a framework for the evolution of artificial general intelligenceMar 25 2019Mar 27 2019In this work, a novel framework for the emergence of general intelligence is proposed, where agents evolve through environmental rewards and learn throughout their lifetime without supervision, i.e., self-supervised learning through embodiment. The chosen ... More
Towards a framework for the evolution of artificial general intelligenceMar 25 2019In this work, a novel framework for the emergence of general intelligence is proposed, where agents evolve through environmental rewards and learn throughout their lifetime without supervision, i.e., self-supervised learning through embodiment. The chosen ... More
Ethics of Artificial Intelligence DemarcationsApr 23 2019In this paper we present a set of key demarcations, particularly important when discussing ethical and societal issues of current AI research and applications. Properly distinguishing issues and concerns related to Artificial General Intelligence and ... More
Reservoir Computing Using Non-Uniform Binary Cellular AutomataFeb 13 2017The Reservoir Computing (RC) paradigm utilizes a dynamical system, i.e., a reservoir, and a linear classifier, i.e., a read-out layer, to process data from sequential classification tasks. In this paper the usage of Cellular Automata (CA) as a reservoir ... More
Ethics of Artificial Intelligence DemarcationsApr 23 2019May 16 2019In this paper we present a set of key demarcations, particularly important when discussing ethical and societal issues of current AI research and applications. Properly distinguishing issues and concerns related to Artificial General Intelligence and ... More
Towards a framework for the evolution of artificial general intelligenceMar 25 2019Apr 25 2019In this work, a novel framework for the emergence of general intelligence is proposed, where agents evolve through environmental rewards and learn throughout their lifetime without supervision, i.e., self-supervised learning through embodiment. The chosen ... More
Evolved Art with Transparent, Overlapping, and Geometric ShapesApr 12 2019May 16 2019In this work, an evolutionary art project is presented where images are approximated by transparent, overlapping and geometric shapes of different types, e.g., polygons, circles, lines. Genotypes representing features and order of the geometric shapes ... More
DeepTEGINN: Deep Learning Based Tools to Extract Graphs from Images of Neural NetworksJul 01 2019In the brain, the structure of a network of neurons defines how these neurons implement the computations that underlie the mind and the behavior of animals and humans. Provided that we can describe the network of neurons as a graph, we can employ methods ... More
Autonomous Configuration of Network Parameters in Operating Systems using Evolutionary AlgorithmsAug 31 2018By default, the Linux network stack is not configured for highspeed large file transfer. The reason behind this is to save memory resources. It is possible to tune the Linux network stack by increasing the network buffers size for high-speed networks ... More
Achieving Connectivity Between Wide Areas Through Self-Organising Robot Swarm Using Embodied EvolutionJul 12 2018Abruptions to the communication infrastructure happens occasionally, where manual dedicated personnel will go out to fix the interruptions, restoring communication abilities. However, sometimes this can be dangerous to the personnel carrying out the task, ... More
Evaluation of the criticality of in vitro neuronal networks: Toward an assessment of computational capacityJul 04 2019Novel computing hardwares are necessary to keep up with today's increasing demand for data storage and processing power. In this research project, we turn to the brain for inspiration to develop novel computing substrates that are self-learning, scalable, ... More
Characterization of spin-orbit interactions of GaAs heavy holes using a quantum point contactMay 12 2014Jul 31 2014We present transport experiments performed in high quality quantum point contacts embedded in a GaAs two-dimensional hole gas. The strong spin-orbit interaction results in peculiar transport phenomena, including the previously observed anisotropic Zeeman ... More
Evolved Art with Transparent, Overlapping, and Geometric ShapesApr 12 2019In this work, an evolutionary art project is presented where images are approximated by transparent, overlapping and geometric shapes of different types, e.g., polygons, circles, lines. Genotypes representing features and order of the geometric shapes ... More
Evolved Art with Transparent, Overlapping, and Geometric ShapesApr 12 2019May 15 2019In this work, an evolutionary art project is presented where images are approximated by transparent, overlapping and geometric shapes of different types, e.g., polygons, circles, lines. Genotypes representing features and order of the geometric shapes ... More
A general representation of dynamical systems for reservoir computingJul 03 2019Dynamical systems are capable of performing computation in a reservoir computing paradigm. This paper presents a general representation of these systems as an artificial neural network (ANN). Initially, we implement the simplest dynamical system, a cellular ... More
Hydrodynamic Limit for an Anharmonic Chain under Boundary TensionFeb 06 2018May 25 2019We study the hydrodynamic limit for the isothermal dynamics of an anharmonic chain under hyperbolic space-time scaling under varying tension. The temperature is kept constant by a contact with a heat bath, realised via a stochastic momentum-preserving ... More
Hydrodynamic Limit for an Anharmonic Chain under Boundary TensionFeb 06 2018Jun 11 2018We study the hydrodynamic limit for the isothermal dynamics of an anharmonic chain under hyperbolic space-time scaling under varying tension. The temperature is kept constant by a contact with a heat bath, realised via a stochastic momentum-preserving ... More
On a quadratic functional for scalar conservation lawsNov 12 2013We prove a quadratic interaction estimate for approximate solutions to scalar conservation laws obtained by the wavefront tracking approximation or the Glimm scheme. This quadratic estimate has been used in the literature to prove the convergence rate ... More
On the existence of $L^2$-valued thermodynamic entropy solutions for a hyperbolic system with boundary conditionsNov 13 2018May 13 2019We prove existence of $L^2$-weak solutions of a quasilinear wave equation with boundary conditions. This describes the isothermal evolution of a one dimensional non-linear elastic material, attached to a fixed point on one side and subject to a force ... More
A note on the existence of $L^2$ valued solutions for a hyperbolic system with boundary conditionsNov 13 2018Feb 08 2019We prove existence of $L^2$-weak solutions of a quasilinear wave equation with boundary conditions.This is done using a vanishing viscosity approximation with mixed Dirichlet-Neumann boundary conditions. In this setting we obtain a uniform a priori estimate ... More
Hydrodynamic Limit for an Anharmonic Chain under Boundary TensionFeb 06 2018We study the hydrodynamic limit for a one dimensional isothermal anharmonic finite chain in Lagrangian coordinates with hyperbolic space-time scaling. The temperature is kept constant by putting the chain in contact with a heat bath, realised via a stochastic ... More
Quadratic interaction functional for general systems of conservation lawsDec 19 2014For the Glimm scheme approximation $u_\epsilon$ to the solution of the system of conservation laws in one space dimension \begin{equation*} u_t + f(u)_x = 0, \qquad u(0,x) = u_0(x) \in \mathbb R^n, \end{equation*} with initial data $u_0$ with small total ... More
Quantum Teleportation with Continuous Variables: a surveyApr 05 2006Oct 12 2006Very recently we have witnessed a new development of quantum information, the so-called continuous variable (CV) quantum information theory. Such a further development has been mainly due to the experimental and theoretical advantages offered by CV systems, ... More
Deregulating 'the rural'; threatening land management regime. Experiences of space in the Tuscan countrysideJun 04 2011Aug 11 2011In this research the relationships between landownership and the use of rural land are investigated and analyzed through an empirical study, conducted in Tuscany, which was based on interviews with landowners. Through the development of farmers' typologies, ... More
Quantum discord as a resource for quantum cryptographySep 10 2013Aug 11 2014Quantum discord is the minimal bipartite resource which is needed for a secure quantum key distribution, being a cryptographic primitive equivalent to non-orthogonality. Its role becomes crucial in device-dependent quantum cryptography, where the presence ... More
Dissecting cosmic-ray electron-positron data with Occam's Razor: the role of known PulsarsDec 23 2008Apr 28 2009We argue that both the positron fraction measured by PAMELA and the peculiar spectral features reported in the total electron-positron (e+e-) flux measured by ATIC have a very natural explanation in electron-positron pairs produced by nearby pulsars. ... More
Aspects of Statistical Physics in Computational ComplexityMay 14 2014The aim of this review paper is to give a panoramic of the impact of spin glass theory and statistical physics in the study of the K-sat problem. The introduction of spin glass theory in the study of the random K-sat problem has indeed left a mark on ... More
Underlying Event Studies at CDFNov 10 2003We present recent studies about the `underlying event' which originates mostly from soft spectator interactions. First Run II data results are compared to published Run I results and to QCD Monte Carlo models.
Ponderomotive entanglement purificationDec 13 2000It is shown that ponderomotive force can be used to purify entangled states. The protocol is based on the possibility to exploit such force for a local quantum nondemolition measurement of the total excitation number of continuos variable entangled pairs. ... More
One-loop Weak Dipole Form Factors and Weak Dipole Moments of Heavy FermionsMay 13 1998The one-loop weak-magnetic and weak-electric dipole form factors of heavy fermions in a generic model are derived. Numerical predictions for the $\tau$ lepton and $b$ quark Weak Anomalous Magnetic and Electric Dipole Moments (AWMDM and WEDM) in the SM ... More
Hyperbolic volume of representations of fundamental groups of cusped 3-manifoldsMay 19 2003Let W be a compact manifold and let \rho be a representation of its fundamental group into PSL(2,C). The volume of \rho is defined by taking any \rho-equivariant map from the universal cover of W to H^3 and then by integrating the pull-back of the hyperbolic ... More
Fractional Schrödinger equation in opticsJan 09 2015In quantum mechanics, the space-fractional Schr\"{o}dinger equation provides a natural extension of the standard Schr\"{o}dinger equation when the Brownian trajectories in Feynman path integrals are replaced by Levy flights. Here an optical realization ... More
Quantum recurrence and fractional dynamic localization in ac-driven perfect state transfer HamiltoniansMar 08 2014Quantum recurrence and dynamic localization are investigated in a class of ac-driven tight-binding Hamiltonians, the Krawtchouk quantum chain, which in the undriven case provides a paradigmatic Hamiltonian model that realizes perfect quantum state transfer ... More
Field-induced barrier transparency of Bloch waves in tight-binding latticesFeb 02 2011A rectangular potential barrier for a Bloch particle in a tight-binding lattice is shown to become fully transparent by the application of a strong ac field with appropriate amplitude and frequency. Such a curious phenomenon bears some connection with ... More
Controlling the path of discretized light in waveguide latticesFeb 02 2011A general method for flexible control of the path of discretized light beams in homogeneous waveguide lattices, based on longitudinal modulation of the coupling constant, is theoretically proposed. As compared to beam steering and refraction achievable ... More
Bloch oscillations in tight-binding lattices with defectsSep 01 2010Defects in tight-binding lattices generally destroy the onset of Bloch oscillations (BOs) and the periodic self-imaging of the wave packet due to the lack of an equally-spaced Wannier-Stark ladder spectrum. Here it is shown that localized and extended ... More
Bound states in the continuum in a single-level Fano-Anderson modelDec 18 2006Bound states in the continuum (BIC) are shown to exist in a single-level Fano-Anderson model with a colored interaction between the discrete state and a tight-binding continuum, which may describe mesoscopic electron or photon transport in a semi-infinite ... More
Optical realization of relativistic non-Hermitian quantum mechanicsAug 31 2010Light propagation in distributed feedback optical structures with gain/loss regions is shown to provide an accessible laboratory tool to visualize in optics the spectral properties of the one-dimensional Dirac equation with non-Hermitian interactions. ... More
Optical Zener-Bloch oscillations in binary waveguide arraysNov 15 2006Zener tunneling in a binary array of coupled optical waveguides with transverse index gradient is shown to produce a sequence of regular or irregular beam splitting and beam recombination events superimposed to Bloch oscillations. These periodic or aperiodic ... More
Braneworlds and Quantum States of Relativistic ShellsJan 15 2007We review some applications of relativistic shells that are relevant in the context of quantum gravity/quantum cosmology. Using a recently developed approach, the stationary states of this general relativistic system can be determined in the semiclassical ... More
On the better constraints from the South Pole Telescope Sunyaev-Zel'dovich galaxy clusters survey: a FoM evaluation for the equation of state of Dark EnergyDec 29 2011Jan 03 2012In a recent article by Benson et al., 2011, the authors show the latest measurements from the South Pole Telescope (SPT) Sunyaev Zel'dovich (SZ) cluster survey to better constrain some cosmological parameters. In particular, the authors found that adding ... More
Wavelet Analysis of Solar ActivityJan 20 2000Using wavelet analysis approach, the temporal variations of solar activity on time scales ranging from days to decades, are examined from the daily time series of sunspot numbers. A hierarchy of changing complex periods are careful detected and related ... More
Advanced Statistical Methods for Large-Scale Structure StudiesOct 06 1995These Lecture Notes are devoted to an introductory description of some of the most widely applied statistical methods for the analysis of the Large-Scale Structure (LSS) of the Universe. Rather than providing technical details about the implementation ... More
Scaling in the UniverseApr 22 1994Apr 25 1994The aim of this review article is to give a comprehensive description of the scaling properties detected for the distribution of cosmic structures. Due to the great variety of statistical methods to describe the large-scale structure of the Universe, ... More
The process `e+ e- --> H t t-bar' and its backgrounds at future electron-positron collidersFeb 01 1999The process $e^+e^-\to H t\bar t$ can be used at the Next Linear Collider to measure the Higgs-top Yukawa coupling. In this paper, we compute $2\to 8$ processes of the form $e^+e^-\to b\bar b b\bar b W^+W^-\to b\bar b b\bar b \ell^\pm\nu_\ell q\bar q'$, ... More
Higgs signals and hard photons at the Next Linear Collider: the $ZZ$-fusion channel in the Standard ModelAug 27 1996In this paper, we extend the analyses carried out in a previous article for $WW$-fusion to the case of Higgs production via $ZZ$-fusion within the Standard Model at the Next Linear Collider, in presence of electromagnetic radiation due real photon emission. ... More
The intermediate-mass Standard Model Higgs boson at the NLC: reducible and irreducible backgrounds to the Bjorken production channelJul 08 1995Both the reducible and irreducible backgrounds to the Higgs production channel \eehz\ at a Next Linear Collider (NLC) are studied, for the Standard Model (\sm) Higgs boson in the intermediate-mass range. A phenomenological analysis that does not exploit ... More
Analogue gravitational phenomena in Bose-Einstein condensatesAug 23 2012Analogue gravity is based on the simple observation that perturbations propagating in several physical systems can be described by a quantum field theory in a curved spacetime. While phenomena like Hawking radiation are hardly detectable in astrophysical ... More
On sinh-Gordon Thermodynamic Bethe Ansatz and fermionic basisApr 02 2014Jun 19 2014We review the construction of the fermionic basis for sinh-Gordon model and investigate numerically the ultra-violet limit of the one-point functions. We then compare the predictions obtained from this formalism against previously established results. ... More
Gamma-ray band and multi-waveband variability of blazars with the Fermi Large Area Space TelescopeDec 12 2011The Fermi Gamma-ray Space Telescope, as an all-sky survey and monitoring mission, is producing daily/weekly sampled gamma-ray light curves for dozens of blazars and other high-energy sources. Highlights on MeV-GeV gamma-ray variability properties of these ... More
The C = 1 Matrix Model Formulation of Two Dimensional Yang-Mills TheoriesJul 28 1993We find the exact matrix model description of two dimensional Yang-Mills theories on a cylinder or on a torus and with an arbitrary compact gauge group. This matrix model is the singlet sector of a $c =1$ matrix model where the matrix field is in the ... More
Progress in Small x ResummationSep 30 2005I review recent theoretical progress in the resummation of small x contributions to the evolution of parton distributions, in view of its potential significance for accurate phenomenology at future colliders. I show that a consistent perturbative resummation ... More
Polarized Structure Functions: a Theoretical UpdateNov 16 1995Nov 29 1995We review recent developments in the theory and phenomenology of polarized structure functions. We summarize recent experimental data on the proton and deuteron structure function $g_1$, and their impact on the understanding of polarized sum rules. Specifically, ... More
A New Random Coding Technique that Generalizes Superposition Coding and BinningFeb 05 2012Feb 07 2012Proving capacity for networks without feedback or cooperation usually involves two fundamental random coding techniques: superposition coding and binning. Although conceptually very different, these two techniques often achieve the same performance, suggesting ... More
On the Capacity of a General Multiple-Access Channel and of a Cognitive Network in the Very Strong Interference RegimeFeb 05 2012The capacity of the multiple-access channel with any distribution of messages among the transmitting nodes was determined by Han in 1979 and the expression of the capacity region contains a number of rate bounds and that grows exponentially with the number ... More
Frobenius structures on double Hurwitz spacesOct 08 2012We construct Frobenius structures of "dual type" on the moduli space of ramified coverings of $\mathbb{P}^1$ with given ramification type over two points, generalizing a construction of Dubrovin. A complete hierarchy of hydrodynamic type is obtained from ... More
FERM3D: A finite element R-matrix electron molecule scattering codeJul 07 2006FERM3D is a three-dimensional finite element program, for the elastic scattering of a low energy electron from a general polyatomic molecule, which is converted to a potential scattering problem. The code is based on tricubic polynomials in spherical ... More
New FOCUS results on charm mixing and CP violationNov 17 2000Nov 29 2000We present a summary of recent results on CP violation and mixing in the charm quark sector based on a high statistics sample collected by photoproduction experiment FOCUS (E831 at Fermilab). We have measured the difference in lifetimes for the $D^0$ ... More
Interaction of escaping cosmic rays with molecular cloudsApr 03 2013The study of the gamma-ray radiation produced by cosmic rays that escape their accelerators is of paramount importance for (at least) two reasons: first, the detection of those gamma-ray photons can serve to identify the sources of cosmic rays and, second, ... More
Cosmic ray escape from supernova remnantsAug 24 2011Galactic cosmic rays are believed to be accelerated at supernova remnants via diffusive shock acceleration. Though this mechanism gives fairly robust predictions for the spectrum of particles accelerated at the shock, the spectrum of the cosmic rays which ... More
How to use molecular clouds to study the propagation of cosmic rays in the GalaxyNov 09 2010Observations of molecular clouds in the gamma ray domain provide us with a tool to study the distribution of cosmic rays in the Galaxy. This is because cosmic rays can penetrate molecular clouds, undergo hadronic interactions in the dense gas, and produce ... More
Gamma-Ray emission from Clusters of GalaxiesJul 29 2003The nonthermal radiation observed from a handfull of clusters of galaxies (CG) is the proof that particle acceleration occurs in the intracluster medium (ICM). It is often believed that shock surfaces associated with either mergers of CG, or with the ... More
Energy of embedded surfaces invariant under Moebius tranformations, addendumDec 13 1995In a previous preprint we defined an energy associated to every embedding of a surface into $R^n$ or $S^n$. This energy is invariant under Moebius tranformations and the "round" sphere is its only absolute minimum. Here we sketch a proof of the compactness ... More
Parton distribution functions with QED correctionsSep 01 2015Sep 02 2015We present the first unbiased determination of parton distribution functions (PDFs) with electroweak corrections. The aim of this thesis is to provide an exhaustive description of the theoretical framework and the technical implementation which leads ... More
$\mathcal{PT}$ phase control in circular multicore fibersMar 22 2016We consider light dynamics in a circular multicore fiber with balanced gain and loss core distribution, and show that transition from unbroken to broken $\mathcal{PT}$ phases can be conveniently controlled by geometric twist of the fiber. The twist introduces ... More
Necessity is the mother of invention. The role of collective sensing in group formationFeb 22 2016Traditionally, the fields of Sociology and Biology explain how groups could form and remain together if external factors are present, for example an environment that favors group behavior, e.g. avoid predation, or between-group competition. This work ... More
Tunable dynamic Fano resonances in coupled-resonant optical waveguideMay 15 2015A route toward lineshape engineering of Fano resonances in photonic structures is theoretically proposed, which uses dynamic modulation of the refractive index of a microcavity. The method is exemplified by considering coupled-resonator optical waveguide ... More
Device-independent quantum secret sharing using Mermin-type contextualityOct 16 2015Dec 29 2015We present a new quantum secret sharing protocol based on recent advances in Mermin-type contextuality scenarios, which is provably secure against postquantum nonsignaling attackers. It is a fundamental assumption of secret sharing protocols that not ... More
Quantum state transfer by time reversal in the continuumApr 04 2016A method for high-fidelity quantum state transfer in a quantum network coupled to a continuum, based on time reversal in the continuum after decay, is theoretically suggested. Provided that the energy spectrum of the network is symmetric around a reference ... More
A variational approach to symmetry, monotonicity, and comparison for doubly-nonlinear equationsNov 07 2016We advance a variational method to prove qualitative properties such as symmetries, monotonicity, upper and lower bounds, sign properties, and comparison principles for a large class of doubly-nonlinear evolutionary problems including gradient flows, ... More
Planckian corrections to the Friedmann flat equations from thermodynamics at the apparent horizonNov 20 2015Jan 15 2016In this paper we use our recently generalized black hole entropy formula to propose a quantum version of the Friedmann equations. In particular, starting from the differential version of the first law of thermodynamics, we are able to find planckian (non ... More
Statistical properties of dynamics. Introduction to the functional analytic approachOct 09 2015These are lecture notes for a simple minicourse approaching the satistical properties of a dynamical system by the study of the associated transfer operator (considered on a suitable function space). The following questions will be addressed: *existence ... More
Random 'choices' and the locality loopholeOct 01 2015It has been claimed that to close the locality loophole in a Bell experiment, random numbers of quantum origin should be used for selecting the measurement settings. This is how it has been implemented in all recent Bell experiment addressing this loophole. ... More
Variable-length Non-overlapping CodesMay 12 2016We define a variable-length code having the property that no (non-empty) prefix of each its codeword is a suffix of any other one, and vice versa. This kind of code can be seen as an extension of two well-known codes in literature, called respectively ... More
Bidirectional invisibility in Kramers-Kronig optical mediaJul 14 2016A broad class of planar dielectric media with complex permittivity profiles that are fully invisible, for both left and right incidence sides, is introduced. Such optical media are locally isotropic, non-magnetic and belong to the recently discovered ... More
Self-Healing Protocols for Connectivity Maintenance in Unstructured OverlaysJun 15 2015In this paper, we discuss on the use of self-organizing protocols to improve the reliability of dynamic Peer-to-Peer (P2P) overlay networks. Two similar approaches are studied, which are based on local knowledge of the nodes' 2nd neighborhood. The first ... More
The Hilbert series of 3d N=2 Yang-Mills theories with vectorlike matterMay 10 2015This paper presents a formula for the Hilbert series that counts gauge invariant chiral operators in 3d N=2 Yang-Mills theories with vectorlike matter and no Chern-Simons interactions. The formula counts 't Hooft monopole operators dressed by gauge invariants ... More
The characteristic gluing problem and conservation laws for the wave equation on null hypersurfacesOct 04 2013We obtain necessary and sufficient conditions for the existence of "conservation laws" on null hypersurfaces for the wave equation on general four-dimensional Lorentzian manifolds. Examples of null hypersurfaces exhibiting such conservation laws include ... More
Horizon Instability of Extremal Black HolesJun 28 2012Mar 12 2013We show that axisymmetric extremal horizons are unstable under linear scalar perturbations. Specifically, we show that translation invariant derivatives of generic solutions to the wave equation do not decay along such horizons as advanced time tends ... More
A note on instabilities of extremal black holes under scalar perturbations from afarDec 05 2012Apr 16 2013In previous work of the author it was shown that instabilities of solutions to the wave equation develop asymptotically along the event horizon of extremal Kerr provided a certain expression H of the initial data is non-trivial on the horizon. In this ... More
Entropy production for an interacting quark-gluon plasmaMay 17 2011We investigate the entropy production within dissipative hydrodynamics in the Israel-Stewart (IS) and Navier-Stokes theory (NS) for relativistic heavy ion physics applications. In particular we focus on the initial condition in a 0+1D Bjorken scenario, ... More
A Novel Approach to the Statistical Modeling of Wireline ChannelsJan 10 2011We report here that channel power gain and Root-Mean-Square Delay Spread (RMS-DS) in Low/Medium Voltage power line channels are negatively correlated lognormal random variables. Further analysis of other wireline channels allows us to report a strong ... More
Definition and Implementation of a Points-To Analysis for C-like LanguagesOct 04 2008The points-to problem is the problem of determining the possible run-time targets of pointer variables and is usually considered part of the more general aliasing problem, which consists in establishing whether and when different expressions can refer ... More
On M. Mérigot's theorem on the convergence domain of the Campbell-Baker-Hausdorff-Dynkin seriesApr 27 2013The aim of this manuscript is to present the proof given by Michel M\'erigot in 1974 for an enlarged convergence domain of the Campbell-Baker-Hausdorff-Dynkin series in the Lie algebra of a Banach-Lie group. This proof is based on a theorem, of independent ... More
Self-organisation to criticality in a system without conservation lawApr 23 2002We numerically investigate the approach to the stationary state in the nonconservative Olami-Feder-Christensen (OFC) model for earthquakes. Starting from initially random configurations, we monitor the average earthquake size in different portions of ... More
Quantum interference and exceptional pointsDec 08 2018Exceptional points (EPs), i.e. branch point singularities of non-Hermitian Hamiltonians, are ubiquitous in optics. So far, the signatures of EPs have been mostly studied assuming classical light. In the passive parity-time ($\mathcal{PT}$) optical coupler, ... More
Super-multiplicativity of ideal norms in number fieldsOct 04 2018In this article we study inequalities of ideal norms. We prove that in a subring $R$ of a number field every ideal can be generated by at most $3$ elements if and only if the ideal norm satisfies $N(IJ) \geq N(I)N(J)$ for every pair of non-zero ideals ... More
On a physical description and origin of the cosmological constantSep 28 2018Oct 16 2018In this paper we use and extend the results present in \cite{1,2,3,4} and in particular in \cite{4} to obtain a statistical description of the cosmological constant in a cosmological de Sitter universe in terms of massless excitations with Planckian effects. ... More
The L2 strong maximum principle on arbitrary countable networksFeb 02 2009May 17 2011We study the strong maximum principle for the heat equation associated with the Dirichlet form on countable networks. We start by analyzing the boundedness properties of the incidence operators on a countable network. Subsequently, we prove that the strong ... More
Convective and absolute PT symmetry breaking in tight-binding latticesOct 18 2013We investigate the onset of parity-time ($\mathcal{PT}$) symmetry breaking in non-Hermitian tight-binding lattices with spatially-extended loss/gain regions in presence of an advective term. Similarly to the instability properties of hydrodynamic open ... More
A Process-Theoretic Church of the Larger Hilbert SpaceMay 30 2019We show how to reconstruct a process theory of local systems starting from a global theory of reversible processes on a single global system, by using the purification principle. In such a process theory, local systems are not given, but rather `emerge' ... More
Equilibrium and nonequilibrium properties of systems with long-range interactionsNov 07 2007We briefly review some equilibrium and nonequilibrium properties of systems with long-range interactions. Such systems, which are characterized by a potential that weakly decays at large distances, have striking properties at equilibrium, like negative ... More
End-to-end capacities of a quantum communication networkMay 29 2019In quantum mechanics, a fundamental law prevents quantum communications to simultaneously achieve high rates and long distances. This limitation is well known for point-to-point protocols, where two parties are directly connected by a quantum channel, ... More
On a spectral property of one-dimensional representations of compact quantum groupsJun 02 2016In the $C^*$-algebraic setting the spectrum of any group-like element of a compact quantum group is shown to be a closed subgroup of the one-dimensional torus. A number of consequences of this fact are then illustrated, along with a loose connection with ... More
On a characterization of dual Banach spaces through determinant subspaces of norm-attaining linear formsSep 27 2009Mar 10 2010Necessary and sufficient conditions for Banach space to be(isometrically isomorphic to) a dual space will be given.
The Banach-Alaoglu theorem is equivalent to the Tychonoff theorem for compact Hausdorff spacesNov 02 2009Nov 25 2009In this brief note we provide a simple approach to give a new proof of the well known fact that the Banach-Alaoglu theorem and the Tychonoff product theorem for compact Hausdorff spaces are equivalent.
The Isoperimetric Profile of a Noncompact Riemannian Manifold for Small VolumesSep 02 2010Oct 02 2012In the main theorem of this paper we treat the problem of existence of minimizers of the isoperimetric problem under the assumption of small volumes. Applications of the main theorem to asymptotic expansions of the isoperimetric problem are given.
Consensus-Based Torque Control of Deloaded Wind DFIGs for Distributed and Fair Dynamic DispatchingFeb 12 2016In this paper we aim to address the problem of dynamically dispatching a group of state-of-the-art deloaded wind generators (WGs) in a fair-sharing manner. We use the term dynamically since the WGs aim to dispatch themselves according to a varying committed ... More
Role of conserved quantities in Fourier's law for diffusive mechanical systemsMay 19 2019Jun 23 2019Energy transport can be influenced by the presence of other conserved quantities. We consider here diffusive systems where energy and the other conserved quantities evolve macroscopically on the same diffusive space-time scale. In these situations the ... More