Results for "Marco Ajello"

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The peak region of the extragalactic background radiationFeb 18 2009Feb 20 2009The Cosmic X-ray background carries the information of cosmic accretion onto super-massive black holes. The intensity at its peak can be used to constrain the integrated space density of highly obscured AGNs. Determining the shape and intensity of the ... More
Identifying the 3FHL catalog: CTIO resultsJan 30 2019Jan 31 2019Active galactic Nuclei (AGNs) with their relativistic jets pointed towards the observer, form a subclass of luminous gamma-ray sources commonly known as blazars. The study of blazars is essential to improve our understanding on the AGNs emission mechanisms ... More
Identifying the 3FHL catalog: I. Archival Swift Observations and Source ClassificationJan 22 2019We present the results of an identification campaign of unassociated sources from the Fermi Large Area Telescope 3FHL catalog. Out of 200 unidentified sources, we selected 110 sources for which archival Swift-XRT observations were available, 52 of which ... More
Compton thick AGN in the NuSTAR eraJan 07 2018We present the 2-100 keV spectral analysis of 30 candidate Compton thick (CT-) active galactic nuclei (AGN) selected in the Swift-BAT 100-month survey. The average redshift of these objects is $\langle z\rangle\sim$0.03 and they all lie within $\sim$500 ... More
Deeply x-raying the high-energy skyJan 21 2016All-sky explorations by Fermi-LAT have revolutionized our view of the gamma-ray sky. While its ongoing all-sky survey counts thousands of sources, essential issues related to the nature of unassociated sources call for sensitive all-sky surveys at hard ... More
Spectral analysis of Fermi-LAT blazars above 50 GeVOct 27 2015Nov 05 2015We present an analysis of the intrinsic (unattenuated by the extragalactic background light, EBL) power-law spectral indices of 128 extragalactic sources detected up to z~2 with the Fermi-Large Area Telescope (LAT) at very high energies (VHEs, E>50 GeV). ... More
Combining the Swift/BAT and the INTEGRAL/ISGRI observationsJan 18 2012Current surveys of Active Galactic Nuclei (AGN) find only a very small fraction of AGN contributing to the Cosmic X-ray Background (CXB) at energies above 15 keV. Roughly 99% of the CXB is so far unresolved. In this work we address the question of the ... More
A GeV-TeV Measurement of the Extragalactic Background LightMar 07 2019Mar 11 2019The Extragalactic Background Light (EBL) can be probed via the absorption imprint it leaves in the spectra of gamma-ray sources ($\gamma\gamma \rightarrow e^-e^+$). We recently developed a dedicated technique to reconstruct the EBL, and its evolution ... More
Chandra and NuSTAR follow-up observations of Swift-BAT selected AGNSep 26 2017Based on current models of the Cosmic X-ray Background (CXB), heavily obscured Active Galactic Nuclei (AGN) are expected to make up ~10% of the peak emission of the CXB and ~20% of the total population of AGN, yet few of these sources have been recorded ... More
Identifying the 3FHL catalog: I. Results of the KOSMOS optical spectroscopy campaignSep 14 2018We present the results of the optical spectroscopy follow-up of a sample of 28 unclassified blazars from the Third Fermi-LAT Catalog of High-Energy Sources (3FHL). All the spectra were taken with the 4m Mayall telescope at Kitt Peak. With this follow-up ... More
The deep look onto the hard X-ray sky: The Swift - INTEGRAL X-ray (SIX) surveyJul 31 2012The super-massive black-holes in the centers of Active Galactic Nuclei (AGNs) are surrounded by obscuring matter that can block the nuclear radiation. Depending on the amount of blocked radiation, the flux from the AGN can be too faint to be detected ... More
Compton-thick AGN in the NuSTAR era III: A systematic study of the torus covering factorDec 21 2018We present the analysis of a sample of 35 candidate Compton thick (CT-) active galactic nuclei (AGNs) selected in the nearby Universe (average redshift <z>~0.03) with the Swift-BAT 100-month survey. All sources have available NuSTAR data, thus allowing ... More
EBIT Observation of Ar Dielectronic Recombination Lines Near the Unknown Faint X-Ray Feature Found in the Stacked Spectrum of Galaxy ClustersFeb 04 2019Motivated by possible atomic origins of the unidentified emission line detected at 3.55 keV to 3.57 keV in a stacked spectrum of galaxy clusters (Bulbul et al. 2014), an electron beam ion trap (EBIT) was used to investigate the resonant dielectronic recombination ... More
Intermediate polars in the Swift/BAT survey: Spectra and white dwarf massesJan 22 2009White dwarf masses in cataclysmic variables are difficult to determine accurately, but are fundamental for understanding binary system parameters, as well as binary evolution. We investigate the X-ray spectral properties of a sample of Intermediate Polars ... More
XMM-Newton and INTEGRAL observations of the black hole candidate XTE J1817-330Jul 27 2007The galactic black hole candidate XTE J1817-330 was discovered in outburst by RXTE in January 2006. We present here the results of an XMM-Newton Target of opportunity observation (TOO), performed on 13 March 2006 (44 days after the maximum), and an INTEGRAL ... More
Energetic Particles of Cosmic Accelerators I: Galactic AcceleratorsMar 11 2019The high-energy universe has revealed that energetic particles are ubiquitous in the cosmos and play a vital role in the cultivation of cosmic environments on all scales. Energetic particles in our own galaxy, galactic cosmic rays (GCRs), engage in a ... More
Compton-thick AGN in the NuSTAR era IV: A deep NuSTAR and XMM-Newton view of the candidate Compton thick AGN in ESO 116-G018Dec 13 2018We present the 2--78 keV spectral analysis of the deep NuSTAR and XMM-Newton observation of a nearby Seyfert 2 galaxy, ESO 116-G018, which is selected as a candidate Compton-thick (CT-) active galactic nucleus (AGN) based on a previous Chandra-Swift/BAT ... More
Evidence against star-forming galaxies as the dominant source of IceCube neutrinosNov 02 2015May 21 2016The cumulative emission resulting from hadronic cosmic-ray interactions in star-forming galaxies (SFGs) has been proposed as the dominant contribution to the astrophysical neutrino flux at TeV to PeV energies reported by IceCube. The same particle interactions ... More
An extreme gravitationally redshifted iron line at 4.8 keV in Mrk 876Dec 09 2014X-ray spectral lines at unforeseen energies are important because they can shed light on the extreme physical conditions of the environment around the supermassive black holes of active galactic nuclei (AGN). Mrk 876 displays such a line at 4.8 keV rest-frame ... More
Deriving the contribution of blazars to the Fermi-LAT Extragalactic $γ$-ray background at $E>10$ GeV with efficiency corrections and photon statisticsNov 08 2017The Fermi Large Area Telescope (LAT) Collaboration has recently released the Third Catalog of Hard Fermi-LAT Sources (3FHL), which contains 1556 sources detected above 10 GeV with seven years of Pass 8 data. We investigate the source count distribution ... More
Sensitivity Projections for Dark Matter Searches with the Fermi Large Area TelescopeMay 06 2016May 13 2016The nature of dark matter is a longstanding enigma of physics; it may consist of particles beyond the Standard Model that are still elusive to experiments. Among indirect search techniques, which look for stable products from the annihilation or decay ... More
Evidence against star-forming galaxies as the dominant source of IceCube neutrinosNov 02 2015Apr 21 2017The cumulative emission resulting from hadronic cosmic-ray interactions in star-forming galaxies (SFGs) has been proposed as the dominant contribution to the astrophysical neutrino flux at TeV to PeV energies reported by IceCube. The same particle interactions ... More
2FHL J0826.1-4500: Discovery of a possible shock-cloud interaction on the Western edge of the Vela SNRNov 14 2018We report on the investigation of a very high energy (VHE), Galactic gamma-ray source recently discovered at >50GeV using the Large Area Telescope (LAT) on board the Fermi-LAT. This object, 2FHL J0826.1-4500, displays one of the hardest >50GeV spectra ... More
A GeV-TeV Measurement of the Extragalactic Background LightMar 07 2019The Extragalactic Background Light (EBL) can be probed via the absorption imprint it leaves in the spectra of gamma-ray sources ($\gamma\gamma \rightarrow e^-e^+$). We recently developed a dedicated technique to reconstruct the EBL, and its evolution ... More
Energetic Particles of Cosmic Accelerators II: Active Galactic Nuclei and Gamma-ray BurstsMar 11 2019The high-energy universe has revealed that energetic particles are ubiquitous in the cosmos and play a vital role in the cultivation of cosmic environments on all scales. Though they play a key role in cultivating the cosmological environment and/or enabling ... More
Constraints on the Intergalactic Magnetic Field with Gamma-Ray Observations of BlazarsOct 08 2015Distant BL Lacertae objects emit $\gamma$ rays which interact with the extragalactic background light (EBL), creating electron-positron pairs, and reducing the flux measured by ground-based imaging atmospheric Cherenkov telescopes (IACTs) at very-high ... More
New high-z BL Lacs using the photometric method with Swift and SARASep 11 2017Apr 11 2018BL Lacertae (BL Lac) objects are the prominent members of the third {\it Fermi} Large Area Telescope catalog of $\gamma$-ray sources. Half of the BL Lac population ($\sim$ 300) lack redshift measurements, which is due to the absence of lines in their ... More
The origin of the cosmic gamma-ray background in the MeV rangeFeb 21 2015Feb 15 2016There has been much debate about the origin of the diffuse $\gamma$--ray background in the MeV range. At lower energies, AGNs and Seyfert galaxies can explain the background, but not above $\simeq$0.3 MeV. Beyond $\sim$10 MeV blazars appear to account ... More
Chandra Identification of Two AGN Discovered by INTEGRALFeb 17 2015Here, we report on observations of two hard X-ray sources that were originally discovered with the INTEGRAL satellite: IGR J04059+5416 and IGR J08297-4250. We use the Chandra X-ray Observatory to localize the sources and then archival near-IR images to ... More
Probing the EBL evolution at high redshift using GRBs detected with the Fermi-LATOct 06 2017The extragalactic background light (EBL), from ultraviolet to infrared wavelengths, is predominantly due to emission from stars, accreting black holes and reprocessed light due to Galactic dust. The EBL can be studied through the imprint it leaves, via ... More
Supermassive black holes at high redshiftsMar 14 2019MeV blazars are the most luminous persistent sources in the Universe and emit most of their energy in the MeV band. These objects display very large jet powers and accretion luminosities and are known to host black holes with a mass often exceeding $10^9 ... More
Magnetic Susceptibility of the Quark Condensate and Polarization from Chiral ModelsMar 07 2011We compute the magnetic susceptibility of the quark condensate and the polarization of quarks at zero temperature and in a uniform magnetic background. Our theoretical framework consists of two chiral models that allow to treat self-consistently the spontaneous ... More
Conditionally Evenly Convex Sets and Evenly Quasi-Convex MapsSep 05 2012Evenly convex sets in a topological vector space are defined as the intersection of a family of open half spaces. We introduce a generalization of this concept in the conditional framework and provide a generalized version of the bipolar theorem. This ... More
Complete duality for quasiconvex dynamic risk measures on modules of the $L^{p}$-typeJan 09 2012Sep 05 2012In the conditional setting we provide a complete duality between quasiconvex risk measures defined on $L^{0}$ modules of the $L^{p}$ type and the appropriate class of dual functions. This is based on a general result which extends the usual Penot-Volle ... More
Mean curvature flow of singular Riemannian foliationsAug 22 2014Sep 23 2014Given a singular Riemannian foliation on a compact Riemannian manifold, we study the mean curvature flow equation with a regular leaf as initial datum. We prove that if the leaves are compact and the mean curvature vector field is basic, then any finite ... More
Discovery of GeV Emission from the Circinus galaxy with the Fermi-LATOct 07 2013We report the discovery of gamma-ray emission from the Circinus galaxy using the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. Circinus is a nearby (~4 Mpc) starburst with a heavily obscured Seyfert-type active nucleus, bipolar ... More
Dual Representation of Quasiconvex Conditional MapsJan 20 2010Jan 21 2010We provide a dual representation of quasiconvex maps between two lattices of random variables in terms of conditional expectations. This generalizes the dual representation of quasiconvex real valued functions and the dual representation of conditional ... More
On the dependence on p of the variational eigenvalues of the p-Laplace operatorApr 28 2015We study the behavior of the variational eigenvalues of the p-Laplace operator, with homogeneous Dirichlet boundary condition, when p is varying. After introducing an auxiliary problem, we characterize the continuity answering, in particular, a question ... More
Updated galactic radio constraints on Dark MatterApr 21 2016Aug 01 2016We perform a detailed analysis of the synchrotron signals produced by Dark Matter annihilations and decays. We consider different set-ups for the propagation of electrons and positrons, the galactic magnetic field and Dark Matter properties. We then confront ... More
Numerical computation of soliton dynamics for NLS equations in a driving potentialAug 25 2009Aug 26 2009We provide some numerical computations for the soliton dynamics of the nonlinear Schr\"odinger equation with an external potential. After computing the ground state solution $r$ of a related elliptic equation we show that, in the semi-classical regime, ... More
On a bifurcation value related to quasi-linear Schrodinger equationsNov 02 2011Dec 23 2011By virtue of numerical arguments we study a bifurcation phenomenon occurring for a class of minimization problems associated with the quasi-linear Schrodinger equation.
The e-ASTROGAM mission (exploring the extreme Universe with gamma rays in the MeV-GeV range)Nov 07 2016Jun 04 2017e-ASTROGAM (`enhanced ASTROGAM') is a breakthrough Observatory mission dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV. The mission is based on an advanced space-proven detector technology, with unprecedented ... More
Swift-BAT Survey of Galactic Sources: Catalog and Properties of the populationsSep 07 2010We study the populations of X-ray sources in the Milky Way in the 15-55 keV band using a deep survey with the BAT instrument aboard the Swift observatory. We present the logN-logS distributions of the various source types and we analyze their variability ... More
Fueling lobes of radio galaxies: statistical particle acceleration and the extragalactic gamma-ray backgroundFeb 03 2011The recent discovery of the gamma-ray emission from the lobes of the closest radio galaxy Centaurus A by Fermi implies the presence of high-energy electrons at least up to gamma ~ 10^5 - 10^6. These high-energy electrons are required to interpret the ... More
Compton-thick AGN in the NuSTAR era II: A deep NuSTAR and XMM-Newton view of the candidate Compton thick AGN in NGC 1358Nov 14 2018We present the combined NuSTATR and XMM-Newton 0.6-79 keV spectral analysis of a Seyfert 2 galaxy, NGC 1358, which we selected as a candidate Compton thick (CT-) active galactic nucleus (AGN) on the basis of previous Swift/BAT and Chandra studies. According ... More
General Physical Properties of CGRaBS BlazarsNov 03 2017Nov 07 2017We present the results of a multi-frequency, time-averaged analysis of blazars included in the Candidate Gamma-ray Blazar Survey catalog. Our sample consists of 324 $\gamma$-ray detected ($\gamma$-ray loud) and 191 non $\gamma$-ray detected ($\gamma$-ray ... More
Deformations of products and new examples of obstructed irregular surfacesJan 09 2006We determine the base space of the Kuranishi family of some complete intersection in the product of an abelian variety and a projective space. As a consequence we obtain new examples of obstructed irregular surfaces with ample canonical bundle and maximal ... More
Realistic estimate of valence transversity from dihadron productionOct 10 2015We have updated our extraction of the transversity parton distribution based on the analysis of pion-pair production in deep-inelastic scattering off transversely polarized targets in collinear factorization. The most recent COMPASS data for proton and ... More
Limit points of nets of noncommutative measures on deformations of Weyl C*-algebrasMay 16 2016Jul 04 2016Deformations of classical measures to noncommutative ones play an important role in quantum physics, and in semiclassical and microlocal analysis. In this paper, we characterize cluster points of nets of noncommutative measures acting on the tensor product ... More
B meson mixing at CDF IIOct 26 2005We present the first limit on Bs mixing frequency obtained using 360 pb^-1 of Tevatron Run II data with the CDF II detector. We derive Delta ms 7.9 ps^-1 @ 95 % C.L. with a sensitivity of 8.4 ps^-1. -
Nonperturbative effects and nonperturbative definitions in matrix models and topological stringsMay 20 2008Oct 14 2008We develop techniques to compute multi-instanton corrections to the 1/N expansion in matrix models described by orthogonal polynomials. These techniques are based on finding trans-series solutions, i.e. formal solutions with exponentially small corrections, ... More
The Geometry of Supersymmetric Gauge Theories in Four DimensionsJan 24 1997We review the relations between (twisted) supersymmetric gauge theories in four dimensions and moduli problems in four-dimensional topology, and we study in detail the non-abelian monopole equations from this point of view. The relevance of exact results ... More
Existence and uniqueness of limit cycles in a class of second order ODE's with inseparable mixed termsJun 10 2010We prove a uniqueness result for limit cycles of the second order ODE $\ddot x + \dot x \phi(x,\dot x) + g(x) = 0$. Under mild additional conditions, we show that such a limit cycle attracts every non-constant solution. As a special case, we prove limit ... More
Limit cycle's uniqueness for second order O.D.E.'s polynomial in $\dot x$Nov 08 2010We prove a uniqueness result for limit cycles of the second order ODE $\ddot x + \sum_{j=1}^{J}f_{j}(x)\dot x^{j} + g(x) = 0$. We extend a uniqueness result proved in \cite{CRV}. The main tool applied is an extension of Massera theorem proved in \cite{GS}. ... More
Euler class groups, and the homology of elementary and special linear groupsFeb 18 2015Jan 11 2016We prove homology stability for elementary and special linear groups over rings with many units improving known stability ranges. Our result implies stability for unstable Quillen K-groups and proves a conjecture of Bass. For commutative local rings with ... More
Non-commutative integration, zeta functions and the Haar state for $SU_{q}(2)$Oct 28 2013Sep 16 2014We study a notion of non-commutative integration, in the spirit of modular spectral triples, for the quantum group $SU_{q}(2)$. In particular we define the non-commutative integral as the residue at the spectral dimension of a zeta function, which is ... More
Commutation relations for quantum root vectors of cominuscole parabolicsSep 29 2015We prove a result for the commutator of quantum root vectors corresponding to cominuscole parabolics. Specifically we show that, given two quantum root vectors, belonging respectively to the quantized nilradical and the quantized opposite nilradical, ... More
Comparing invariants of Legendrian knotsApr 04 2014We prove the equivalence of the invariants EH(L) and LOSS-(L) for oriented Legendrian knots L in the 3-sphere equipped with the standard contact structure, partially extending a previous result by Stipsicz and Vertesi. In the course of the proof we relate ... More
On the location of poles for the Ablowitz-Segur family of solutions to the second Painlevé equationMar 14 2012Using a simple operator-norm estimate we show that the solution to the second Painlev\'e equation within the Ablowitz-Segur family is pole-free in a well defined region of the complex plane of the independent variable. The result is illustrated with several ... More
Periods for irregular singular connections on surfacesSep 15 2006We define homology groups for flat irregular singular connections on surfaces and a pairing between these and the de Rham cohomology of the connection, generalizing work of S. Bloch and H. Enault in dimension one. Assuming a conjecture of C. Sabbah (known ... More
Periods for flat algebraic connectionsMar 24 2008In previous work, we established a duality between the algebraic de Rham cohomology of a flat algebraic connection on a smooth quasi-projective surface over the complex numbers and the rapid decay homology of the dual connection relying on a conjecture ... More
Observation of Soft Gamma Repeaters with BeppoSAXMay 15 2003In this paper I will briefly review what are, in my view, the main contributions of BeppoSAX to the understanding of the class of sources known as Soft Gamma Repeaters. These enigmatic sources were firmly identified as steady pulsars just during the operating ... More
Structure formation in Multiple Dark Matter cosmologies with long-range scalar interactionsJun 11 2012(Abridged) An interaction between Cold Dark Matter (CDM) and a classical scalar field playing the role of the cosmic dark energy (DE) might provide long-range dark interactions without conflicting with solar system bounds. Although presently available ... More
Clarifying the effects of interacting dark energy on linear and nonlinear structure formation processesNov 30 2010Jan 31 2011We present a detailed numerical study of the impact that cosmological models featuring a direct interaction between the Dark Energy component that drives the accelerated expansion of the Universe and Cold Dark Matter can have on the linear and nonlinear ... More
Resummation of soft and hard gluon radiation in perturbative QCDDec 03 2012This thesis arises in the context of precision measurements at hadron colliders. The Tevatron and the LHC provide very accurate measurements of many Standard Model processes, such as the production of a lepton pair (Drell-Yan) of high invariant mass. ... More
Semi-dispersing billiards with an infinite cuspJul 18 2001Oct 18 2001Let $f: [0, +\infty) \to (0, +\infty)$ be a sufficiently smooth convex function, vanishing at infinity. Consider the planar domain $Q$ delimited by the positive $x$-semiaxis, the positive $y$-semiaxis, and the graph of $f$. Under certain conditions on ... More
On the dynamics of codimension one holomorphic foliations with ample normal bundleJun 11 2007We investigate the accumulation to singular points of leaves of codimension one foliations whose normal bundle is ample, with emphasis on the nonexistence of Levi-flat hypersurfaces.
Simplified proof of the Theorem of Varopoulos in the commutative caseFeb 02 2008May 02 2008We give continuity properties of bitraces on (possibly non-commutative) Banach *-algebras based on the Closed Graph Theorem, leading to a simplified proof of the Theorem of Varopoulos in the commutative case.
Critical behavior of the Ising model with long range interactionsJul 04 2012We present results of a Monte Carlo study for the ferromagnetic Ising model with long range interactions in two dimensions. This model has been simulated for a large range of interaction parameter $\sigma$ and for large sizes. We observe that the results ... More
A Study of Cross-Over Effects For The 2D Random Bond Potts ModelFeb 09 1998We present results of a numerical simulation of the $q$-state random bond Potts model in two dimensions and for large $q$. In particular, care is taken to study the crossover from the pure model to the random model, as well as the crossover from the percolation ... More
Numerical Results For The 2D Random Bond 3-state Potts ModelJul 09 1995We present results of a numerical simulation of the 3-state Potts model with random bond, in two dimension. In particular, we measure the critical exponent associated to the magnetization and the specific heat. We also compare these exponents with recent ... More
Exact sampling of self-avoiding paths via discrete Schramm-Loewner evolutionMar 15 2010Jul 19 2010We present an algorithm, based on the iteration of conformal maps, that produces independent samples of self-avoiding paths in the plane. It is a discrete process approximating radial Schramm-Loewner evolution growing to infinity. We focus on the problem ... More
Uniform families of ergodic operator netsJun 05 2012Aug 28 2012We study mean ergodicity in amenable operator semigroups and establish the connection to the convergence of strong and weak ergodic nets. We then use these results in order to show the convergence of uniform families of ergodic nets that appear in topological ... More
Topological Dynamics and Grand Unified TheoryApr 14 1997A formalism is presented to construct a non-perturbative Grand Unified Theory when gravitational Planck-scale phenomena are included. The fundamental object on the Planck scale is the three-torus T^3 from which the known properties of superstrings, such ... More
On Quantum Contributions to Black Hole GrowthSep 03 2013Oct 03 2013The effects of Wheeler's quantum foam on black hole growth are explored from an astrophysical perspective. Quantum fluctuations in the form of mini (10^-5 g) black holes can couple to macroscopic black holes and allow the latter to grow exponentially ... More
A Topological Extension of General Relativity to Explore the Nature of Quantum Space-time, Dark Energy and InflationMay 20 2013Jul 17 2013General Relativity is extended into the quantum domain. A thought experiment is explored to derive a specific topological build-up for Planckian space-time. The presented arguments are inspired by Feynman's path integral for superposition and Wheeler's ... More
A Topological Formulation of the Standard ModelNov 15 1997A topological theory for the interactions in Nature is presented. The theory derives from the cyclic properties of the topological manifold Q=2T^3 + 3S^1 x S^2 which has 23 intrinsic degrees of freedom, discrete Z_3 and Z_2 x Z_3 internal groups, an SU(5) ... More
Correction to Nambu-Jona-Lasinio model from QCD at the next-to-leading orderApr 22 2016We evaluate the next-to-leading order correction to the Nambu-Jona-Lasinio model starting from quantum chromodynamics. We show that a systematic expansion exists and that higher order corrections could in principle be computed at any order. In this way, ... More
Chiral symmetry restoration and deconfinement in strong magnetic fieldsFeb 09 2011I review recent results obtained within chiral effective models, on the phase structure of hot quark matter in a strong magnetic background. After a brief introduction, I focus on the results obtained within two chiral models improved with the Polyakov ... More
Phase diagram of hot quark matter under magnetic fieldSep 13 2010In this talk, I review the computation of the phase diagram of hot quark matter in strong magnetic field, at zero baryon density, within an effective model of Quantum Chromodynamics.
Breakdown of thermalization in finite one-dimensional systemsApr 23 2009Sep 02 2009We use quantum quenches to study the dynamics and thermalization of hardcore bosons in finite one-dimensional lattices. We perform exact diagonalizations and find that, far away from integrability, few-body observables thermalize. We then study the breakdown ... More
Finite-temperature properties of hard-core bosons confined on one-dimensional optical latticesJun 16 2005Dec 07 2005We present an exact study of the finite-temperature properties of hard-core bosons (HCB's) confined on one-dimensional optical lattices. Our solution of the HCB problem is based on the Jordan-Wigner transformation and properties of Slater determinants. ... More
Pre-big bang in M-theoryMar 13 2001We discuss a simple cosmological model derived from M-theory. Three assumptions lead naturally to a pre-big bang scenario: (a) 11-dimensional supergravity describes the low-energy world; (b) non-gravitational fields live on a three-dimensional brane; ... More
Geometrodynamical Formulation of Two-Dimensional Dilaton GravityNov 06 1998Two-dimensional matterless dilaton gravity with arbitrary dilatonic potential can be discussed in a unitary way, both in the Lagrangian and canonical frameworks, by introducing suitable field redefinitions. The new fields are directly related to the original ... More
A Solvable Model of Two-Dimensional Dilaton-Gravity Coupled to a Massless Scalar FieldFeb 03 1998We present a solvable model of two-dimensional dilaton-gravity coupled to a massless scalar field. We locally integrate the field equations and briefly discuss the properties of the solutions. For a particular choice of the coupling between the dilaton ... More
Two-Dimensional Dilaton GravityAug 21 1998I briefly summarize recent results on classical and quantum dilaton gravity in 1+1 dimensions.
QCD Studies at Hadron Colliders and in Deeply Virtual Neutrino ScatteringDec 28 2006Dec 29 2006This thesis work summarizes studies in QCD for applications both at hadron colliders and in exclusive processes. In the first part we focus our attention on the study of the initial state scaling violations and the evolution of the unpolarized parton ... More
Muon g-2 in a Model with one Extra DimensionMay 14 2002May 15 2002The computation of the muon anomalous magnetic moment in the framework of a proposed extension of the Standard Model to 5 dimensions is presented. The result (a small correction with respect to the SM prediction) is briefly discussed.
Indirect Searches for Dark Matter: a status reviewFeb 07 2012Mar 04 2013I review in a schematic way the current status of indirect searches for Dark Matter: I list the main relevant experimental results of the recent years and I discuss the excitements and disappointments that their phenomenological interpretations in terms ... More
Interpolation and smoothingAug 29 2002Sep 10 2002Smoothing is omnipresent in astronomy, because almost always measurements performed at discrete positions in the sky need to be interpolated into a smooth map for subsequent analysis. Still, the statistical properties of different interpolation techniques ... More
Enhanced radiometric forcesFeb 03 2004Crookes' Radiometer exploits thermal forces arising from temperature gradients in rarefied gases. This instrument has remained confined to educational physics because of the very small size of the radiometric effect and because of the necessity of an ... More
Quantum vacuum pressure on a conducting slabJul 16 2003The casimir pressure on a non ideal conducting slab is calculated. Using a simple model for the conductivity according to which the slab is perfectly conducting at frequencies below plasma frequency omega_p and perfectly transparent above such frequency, ... More
Noncommutative Motives I: A Universal Characterization of the Motivic Stable Homotopy Theory of SchemesJun 16 2012Jun 17 2013Let $\V$ be a symmetric monoidal model category and let $X$ be an object in $\V$. From this we can construct a new symmetric monoidal model category $Sp^{\Sigma}(\V,X)$ of symmetric spectra objects in $\V$ with respect to $X$, together with a left Quillen ... More
Towards life-long learning of posture control for s-EMG prosthesesNov 20 2015Surface electromyography (s-EMG) sensors are a promising way to control upper-limb prostheses. However a training session is necessary in order to set up the controller that will make s-EMG based movement possible. All data recorded during the training ... More
Instanton sheaves on complex projective spacesDec 07 2004Sep 15 2005We study a class of torsion-free sheaves on complex projective spaces which generalize the much studied mathematical instanton bundles. Instanton sheaves can be obtained as cohomologies of linear monads and are shown to be semistable if its rank is not ... More
On $k$-PN Functions over Finite FieldsDec 24 2013Starting from PN functions, we introduce the concept of $k$-PN functions and classify $k$-PN monomials over finite fields of order $p, p^2$ and $p^4$ for small values of $k$.
Quantum Field Perturbation Theory RevisitedJun 02 2015Mar 03 2016Schwinger's formalism in quantum field theory can be easily implemented in the case of scalar theories in $D$ dimension with exponential interactions, such as $\mu^D\exp(\alpha\phi)$. In particular, we use the relation $$ \exp\big(\alpha{\delta\over \delta ... More
Closed Form of the Baker-Campbell-Hausdorff Formula for the Generators of Semisimple Complex Lie AlgebrasApr 20 2015Oct 24 2016Recently it has been introduced an algorithm Baker-Campbell-Hausdorff (BCH) formula, which extends the Van-Brunt and Visser recent results, leading to new closed forms of BCH formula. More recently, it has been shown that there are {\it 13 types} of such ... More
An algorithm for the Baker-Campbell-Hausdorff formulaFeb 23 2015Apr 27 2015A simple algorithm, which exploits the associativity of the BCH formula, and that can be generalized by iteration, extends the remarkable simplification of the Baker-Campbell-Hausdorff (BCH) formula, recently derived by Van-Brunt and Visser. We show that ... More
Eigenfunctions of the Laplacian Acting on Degree Zero Bundles over Special Riemann SurfacesMay 07 2001Nov 13 2003We find an infinite set of eigenfunctions for the Laplacian with respect to a flat metric with conical singularities and acting on degree zero bundles over special Riemann surfaces of genus greater than one. These special surfaces correspond to Riemann ... More