Results for "G. Tancredi"

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Bifurcation, mode coupling and noise in a nonlinear multimode superconducting RF resonatorApr 12 2013Feb 07 2014The addition of nonlinearity to an harmonic resonator provides a route to complex dynamical behaviour of resonant modes, including coupling between them. We present a superconducting device that makes use of the nonlinearity of Josephson junctions to ... More
Direct spectrum analysis using a threshold detector with application to a superconducting circuitDec 11 2013Dec 16 2013We introduce a new and quantitative theoretical framework for noise spectral analysis using a threshold detector, which is then applied to a superconducting device: the Cavity Bifurcation Amplifier (CBA). We show that this new framework provides direct ... More
Quantum Statistical Parton Distributions and the Spin CrisisApr 03 1996Sep 12 1996Quantum statistical distributions for the partons provide a fair description of deep inelastic scattering data at $Q^2 = 3$ and $10 (GeV/c)^2$. The study of the polarized structure functions seems to suggest an alternative possible solution of the {\it ... More
Calibration of the cross-resonance two-qubit gate between directly-coupled transmonsMay 14 2019Quantum computation requires the precise control of the evolution of a quantum system, typically through application of discrete quantum logic gates on a set of qubits. Here, we use the cross-resonance interaction to implement a gate between two superconducting ... More
Cryogenic coaxial microwave filtersAug 30 2013Feb 06 2014The careful filtering of microwave electromagnetic radiation is critical for controlling the electromagnetic environment for experiments in solid-state quantum information processing and quantum metrology at millikelvin temperatures. We describe the design ... More
Granular physics in low-gravity environments using DEMNov 26 2011Granular materials of different sizes are present on the surface of several atmosphere-less Solar System bodies. The phenomena related to granular materials have been studied in the framework of the discipline called Granular Physics; that has been studied ... More
Size and albedo distributions of asteroids in cometary orbits using WISE dataOct 08 2015We study the distributions of effective diameter ($D$), beaming parameter ($\eta$), and visible geometric albedo ($p_V$) of asteroids in cometry orbits (ACOs) populations, derived from NASA's Wide-field Infrared Explorer (WISE) observations, and compare ... More
Baryon acoustic oscillations from Integrated Neutral Gas Observations: Radio frequency interference measurements and telescope site selectionNov 23 2018The Baryon acoustic oscillations from Integrated Neutral Gas Observations (BINGO) telescope is a new 40-m class radio telescope to measure the large-angular-scale intensity of Hi emission at 980-1260 MHz to constrain dark energy parameters. As it needs ... More
Hadronic Final State in Deep-inelastic Scattering at HERAJan 28 1997Data on the hadronic final state of deep-inelastic events at the ep collider HERA are reviewed. Fragmentation properties in the current region extracted from charged particle spectra are compared to e+e- and fixed target experiments at lower center of ... More
Small-x QCD Effects in Particle Collisions at High EnergiesNov 19 2001Dec 05 2001Recent theoretical developments to calculate cross sections of hadronic objects in the high energy limit are summarised and experimental attempts to establish the need for new QCD effects connected with a resummation of small hadron momentum fractions ... More
Integration by parts identities in integer numbers of dimensions. A criterion for decoupling systems of differential equationsSep 10 2015Nov 05 2015Integration by parts identities (IBPs) can be used to express large numbers of apparently different d-dimensional Feynman Integrals in terms of a small subset of so-called master integrals (MIs). Using the IBPs one can moreover show that the MIs fulfil ... More
Latest Highlights from the H1 CollaborationJun 29 1999Recent data obtained in ep collisions at HERA by the H1 collaboration are presented: searches for new phenomena beyond the Standard Model, measurement of the inclusive neutral and charged current cross sections and of the proton structure function, determination ... More
Renormalisation Scale Dependencies in Dijet Production at HERAJun 29 1999Different choices of the renormalisation scale (muren) can be used to describe hard scattering processes with two jets at large transverse momentum in deep-inelastic scattering at HERA by fixed order perturbative QCD calculations. For leading (LO) and ... More
Elliptic polylogarithms and iterated integrals on elliptic curves II: an application to the sunrise integralDec 19 2017Jul 17 2018We introduce a class of iterated integrals that generalize multiple polylogarithms to elliptic curves. These elliptic multiple polylogarithms are closely related to similar functions defined in pure math- ematics and string theory. We then focus on the ... More
Observation of Events with Isolated Charged Leptons and Large Missing Tra nsverse Momentum and of Events with Multi-Electrons at HERAJul 23 2003Jul 31 2003Striking events with isolated charged leptons, large missing transverse momentum and large transverse momentum of the hadronic final state (PTX) have been observed at the electron proton collider HERA. In the full HERA-I data sample corresponding to an ... More
Jet Production in Deep-inelastic Scattering at HERASep 04 1997The main experimental results on jet production at HERA are reviewed. A study of jet shapes shows that the internal structure of jets is well understood. The potential to accurately determine the strong coupling constant using jet rates is discussed. ... More
Elliptic polylogarithms and iterated integrals on elliptic curves I: general formalismDec 19 2017We introduce a class of iterated integrals, defined through a set of linearly independent integration kernels on elliptic curves. As a direct generalisation of multiple polylogarithms, we construct our set of integration kernels ensuring that they have ... More
Elliptic polylogarithms and two-loop Feynman integralsJul 17 2018We review certain classes of iterated integrals that appear in the computation of Feynman integrals that involve elliptic functions. These functions generalise the well-known class of multiple polylogarithms to elliptic curves and are closely related ... More
From modular forms to differential equations for Feynman integralsJul 02 2018In these proceedings we discuss a representation for modular forms that is more suitable for their application to the calculation of Feynman integrals in the context of iterated integrals and the differential equation method. In particular, we show that ... More
Elliptic polylogarithms and Feynman parameter integralsFeb 26 2019In this paper we study the calculation of multiloop Feynman integrals that cannot be expressed in terms of multiple polylogarithms. We show in detail how certain types of two- and three-point functions at two loops, which appear in the calculation of ... More
Statistical Inspired Parton Distributions and the Violation of QPM Sum RulesJul 16 1996A quantum statistical parametrization of parton distributions has been considered. In this framework, the exclusion Pauli principle connects the violation of the Gottfried sum rule with the Ellis and Jaffe one, and implies a defect in the Bjorken sum ... More
A photometric search for active Main Belt asteroidsJan 22 2014It is well known that some Main Belt asteroids show comet-like features. A representative example is the first known Main Belt comet 133P/(7968) Elst-Pizarro. If the mechanisms causing this activity are too weak to develop visually evident comae or tails, ... More
Two-loop QCD helicity amplitudes for $q\bar q \to W^\pm γ$ and $q\bar q \to Z^0 γ$Dec 07 2011Feb 18 2013The self-couplings of the electroweak gauge bosons are probed at hadron colliders through the production of a massive gauge boson and a photon. To extend the theoretical description of this type of final states towards next-to-next-to-leading order (NNLO) ... More
A hierarchical Bayesian approach to record linkage and population size problemsNov 11 2010Jul 28 2011We propose and illustrate a hierarchical Bayesian approach for matching statistical records observed on different occasions. We show how this model can be profitably adopted both in record linkage problems and in capture--recapture setups, where the size ... More
Differential equations and dispersion relations for Feynman amplitudes. The two-loop massive sunrise and the kite integralFeb 03 2016Apr 07 2016It is shown that the study of the imaginary part and of the corresponding dispersion relations of Feynman graph amplitudes within the differential equations method can provide a powerful tool for the solution of the equations, especially in the massive ... More
On the maximal cut of Feynman integrals and the solution of their differential equationsOct 26 2016The standard procedure for computing scalar multi-loop Feynman integrals consists in reducing them to a basis of so-called master integrals, derive differential equations in the external invariants satisfied by the latter and, finally, try to solve them ... More
Flavour transitions of Dirac-Majorana neutrinosMar 27 1998From a phenomenological point of view, we study active-active and active-sterile flavour-changing (and flavour-conserving) oscillations of Dirac-Majorana neutrinos both in vacuum and in matter. The general expressions for the transition probabilities ... More
Pontecorvo neutrino-antineutrino oscillations: theory and experimental limitsMay 19 1997We study Pontecorvo neutrino-antineutrino oscillations both in vacuum and in matter within a field theoretic approach, showing that this phenomenon can occur only if neutrinos have a Dirac-Majorana mass term. We find that matter effects suppress these ... More
Maximal cuts and differential equations for Feynman integrals. An application to the three-loop massive banana graphApr 18 2017Nov 23 2018We consider the calculation of the master integrals of the three-loop massive banana graph. In the case of equal internal masses, the graph is reduced to three master integrals which satisfy an irreducible system of three coupled linear differential equations. ... More
On the maximal cut of Feynman integrals and the solution of their differential equationsOct 26 2016Jan 20 2017The standard procedure for computing scalar multi-loop Feynman integrals consists in reducing them to a basis of so-called master integrals, derive differential equations in the external invariants satisfied by the latter and, finally, try to solve them ... More
Circuit quantum acoustodynamics with surface acoustic wavesMar 13 2017The experimental investigation of quantum devices incorporating mechanical resonators has opened up new frontiers in the study of quantum mechanics at a macroscopic level$^{1,2}$. Superconducting microwave circuits have proven to be a powerful platform ... More
Double-sided coaxial circuit QED with out-of-plane wiringMar 16 2017Jun 01 2017Superconducting circuits are well established as a strong candidate platform for the development of quantum computing. In order to advance to a practically useful level, architectures are needed which combine arrays of many qubits with selective qubit ... More
Schouten identities for Feynman graph amplitudes; the Master Integrals for the two-loop massive sunrise graphNov 13 2013Jan 28 2014A new class of identities for Feynman graph amplitudes, dubbed Schouten identities, valid at fixed integer value of the dimension d is proposed. The identities are then used in the case of the two loop sunrise graph with arbitrary masses for recovering ... More
An Elliptic Generalization of Multiple PolylogarithmsSep 11 2017Oct 10 2017We introduce a class of functions which constitutes an obvious elliptic generalization of multiple polylogarithms. A subset of these functions appears naturally in the \epsilon-expansion of the imaginary part of the two-loop massive sunrise graph. Building ... More
Algebraicity of Nash sets and of their asymmetric cobordismNov 18 2016This paper deals with the existence of algebraic structures on compact Nash sets. We introduce the algebraic-topological notion of asymmetric Nash cobordism between compact Nash sets, and we prove that a compact Nash set is semialgebraically homeomorphic ... More
The two-loop helicity amplitudes for $gg \to V_1 V_2 \to 4~\mathrm{leptons}$Mar 30 2015Sep 11 2015We compute the two-loop massless QCD corrections to the helicity amplitudes for the production of two electroweak gauge bosons in the gluon fusion channel, $gg \to V_1 V_2$, keeping the virtuality of the vector bosons $V_1$ and $V_2$ arbitrary and taking ... More
A non-planar two-loop three-point function beyond multiple polylogarithmsJan 20 2017We consider the analytic calculation of a two-loop non-planar three-point function which contributes to the two-loop amplitudes for $t \bar{t}$ production and $\gamma \gamma$ production in gluon fusion through a massive top-quark loop. All subtopology ... More
Simultaneous bistability of qubit and resonator in circuit quantum electrodynamicsNov 30 2016Jan 02 2017We explore the joint activated dynamics exhibited by two quantum degrees of freedom: a cavity mode oscillator which is strongly coupled to a superconducting qubit in the strongly coherently driven dispersive regime. Dynamical simulations and complementary ... More
Simultaneous bistability of qubit and resonator in circuit quantum electrodynamicsNov 30 2016We explore the joint activated dynamics exhibited by two quantum degrees of freedom: a cavity mode oscillator which is strongly coupled to a superconducting qubit in the strongly coherently driven dispersive regime. Dynamical simulations and complementary ... More
The two-loop helicity amplitudes for $q \bar q' \to V_1 V_2 \to 4~\mathrm{leptons}$Mar 16 2015Sep 11 2015We compute the two-loop massless QCD corrections to the helicity amplitudes for the production of two massive vector bosons in quark-antiquark annihilation, allowing for an arbitrary virtuality of the vector bosons: $q \bar q' \to V_1V_2$. Combining with ... More
Two-loop $gg \to Hg$ amplitude mediated by a nearly massless quarkOct 12 2016Nov 30 2016We analytically compute the two-loop scattering amplitude $gg \to Hg$ assuming that the mass of the quark, that mediates the ggH interaction, is vanishingly small. Our computation provides an important ingredient required to improve the theoretical description ... More
Events with Isolated Charged Leptons and Large Missing Transverse Momentum at HERAFeb 02 2004Striking events with isolated charged leptons, large missing transverse momentum and large transverse momentum of the hadronic final state were observed at the electron proton collider HERA in a data sample corresponding to a luminosity of about 130 pb-1. ... More
Two-loop electroweak corrections to Higgs-gluon couplings to higher orders in the dimensional regularization parameterOct 18 2016We compute the two-loop electroweak correction to the production of the Higgs boson in gluon fusion to higher orders in the dimensional-regularization parameter $\epsilon = (d-4)/2$. We employ the method of differential equations to compute the relevant ... More
The semileptonic form factors of B and D mesons in the Quark Confinement ModelMay 03 1999The form factors of the weak currents, which appear in the semileptonic decays of the heavy pseudoscalar mesons, are calculated within the quark confinement model by taking into account, for the first time, the structure of heavy meson vertex and the ... More
Two-loop amplitudes for $q g \to H q$ and $q \bar{q} \to H g$ mediated by a nearly massless quarkFeb 01 2017We compute the two-loop QCD corrections to $q g \to H q$ and $q \bar{q} \to H g$ amplitudes mediated by loops of nearly massless quarks. These amplitudes provide the last missing ingredient required to compute the NLO QCD corrections to the top-bottom ... More
Higher order corrections to mixed QCD-EW contributions to Higgs production in gluon fusionJan 31 2018Apr 19 2018We present an estimate of the next-to-leading order QCD corrections to mixed QCD-electroweak contribution to Higgs boson production cross section in gluon fusion, combining the recently computed three-loop virtual corrections and the approximate treatment ... More
Two-loop QCD helicity amplitudes for $g\,g \to Z\,g$ and $g\,g \to Z\,γ$Feb 11 2013Apr 23 2013We compute the helicity amplitudes for the processes $gg\to Zg$ and $gg\to Z\gamma$ to two loops in massless QCD. The perturbative expansion of these processes starts only at the one-loop level, such that our results are a crucial ingredient to the NLO ... More
Hadronic final states in deep-inelastic scattering with SherpaDec 18 2009We extend the multi-purpose Monte-Carlo event generator Sherpa to include processes in deeply inelastic lepton-nucleon scattering. Hadronic final states in this kinematical setting are characterised by the presence of multiple kinematical scales, which ... More
Hadronic final states in DIS with SherpaJun 29 2010We present an extension of the multi-purpose Monte-Carlo event generator Sherpa for processes in deeply inelastic lepton-nucleon scattering. Hadronic final states in this kinematical setting are characterised by the presence of multiple kinematical scales, ... More
Two-Loop Master Integrals for $q \bar{q} \to V V$: the Planar TopologiesJun 26 2013Aug 23 2013The two-loop QCD corrections to vector boson pair production at hadron colliders involve a new class of Feynman integrals: two-loop four-point functions with two off-shell external legs. We describe their reduction to a small set of master integrals by ... More
Studies of Quantum Chromodynamics at the LHCJun 10 2015Jul 16 2015A successful description of hadron-hadron collision data demands a profound understanding of quantum chromodynamics. Inevitably, the complexity of strong-interaction phenomena requires the use of a large variety of theoretical techniques -- from perturbative ... More
Two-loop $gg \to Hg$ amplitude mediated by a nearly massless quarkOct 12 2016We analytically compute the two-loop scattering amplitude $gg \to Hg$ assuming that the mass of the quark, that mediates the ggH interaction, is vanishingly small. Our computation provides an important ingredient required to improve the theoretical description ... More
A posteriori inclusion of PDFs in NLO QCD final-state calculationsOct 25 2005Any NLO calculation of a QCD final-state observable involves Monte Carlo integration over a large number of events. For DIS and hadron colliders this must usually be repeated for each new PDF set, making it impractical to consider many `error' PDF sets, ... More
Three-loop mixed QCD-electroweak corrections to Higgs boson gluon fusionNov 29 2017May 09 2018We compute the contribution of three-loop mixed QCD-electroweak corrections ($\alpha_S^2\alpha^2$) to the $gg \to H$ scattering amplitude. We employ the method of differential equations to compute the relevant integrals and express them in terms of Goncharov ... More
Two-loop electroweak corrections to Higgs-gluon couplings to higher orders in the dimensional regularization parameterOct 18 2016Feb 02 2017We compute the two-loop electroweak correction to the production of the Higgs boson in gluon fusion to higher orders in the dimensional-regularization parameter $\epsilon = (d-4)/2$. We employ the method of differential equations to compute the relevant ... More
Generalized Bayesian Record Linkage and Regression with Exact Error PropagationOct 11 2018Record linkage (de-duplication or entity resolution) is the process of merging noisy databases to remove duplicate entities. While record linkage removes duplicate entities from such databases, the downstream task is any inferential, predictive, or post-linkage ... More
Double-real contribution to the quark beam function at N$^{3}$LO QCDSep 17 2018We compute the master integrals required for the calculation of the double-real emission contributions to the matching coefficients of jettiness beam functions at next-to-next-to-next-to-leading order in perturbative QCD. As an application, we combine ... More
QCD corrections to $W^+W^-$ production through gluon fusionNov 27 2015We compute the next-to-leading order (NLO) QCD corrections to the $gg \to W^+ W^- \to l^+_1 \nu_1 l^-_2 \bar \nu_2$ process, mediated by a massless quark loop, at the LHC. This process first contributes to the hadroproduction of $W^+W^-$ at $\mathcal{O}(\alpha_s^2)$, ... More
QCD corrections to ZZ production in gluon fusion at the LHCSep 22 2015We compute the next-to-leading order QCD corrections to the production of two Z-bosons in the annihilation of two gluons at the LHC. Being enhanced by a large gluon flux, these corrections provide distinct and, potentially, the dominant part of the N$^3$LO ... More
Phenomenological Bounds on B to Light Semileptonic Form FactorsAug 13 1998The form factors for the weak currents between B and light mesons are studied by relating them to the corresponding D form factors at q^2_{max} according to HQET, by evaluating them at q^2=0 by QCD sum rules, and by assuming a polar q^2 dependence. The ... More
Containment and resolution of hadronic showers at the FCCApr 05 2016May 04 2016The particles produced at a potential Future Circular Collider with $\sqrt{s}$ = 100 TeV are of unprecented energies. In this document we present the hadronic shower containment and resolution parametrizations based on Geant4 simulations for the Hadronic ... More
Triple-real contribution to the quark beam function in QCD at next-to-next-to-next-to-leading orderApr 04 2019We compute the three-loop master integrals required for the calculation of the triple-real contribution to the N$^3$LO quark beam function due to the splitting of a quark into a virtual quark and three collinear gluons, $q \to q^*+ggg$. This provides ... More
Elliptic symbol calculus: from elliptic polylogarithms to iterated integrals of Eisenstein seriesMar 27 2018We present a generalization of the symbol calculus from ordinary multiple polylogarithms to their elliptic counterparts. Our formalism is based on a special case of a coaction on large classes of periods that is applied in particular to elliptic polylogarithms ... More
Elliptic Feynman integrals and pure functionsSep 27 2018We propose a variant of elliptic multiple polylogarithms that have at most logarithmic singularities in all variables and satisfy a differential equation without homogeneous term. We investigate several non-trivial elliptic two-loop Feynman integrals ... More
The Two-Loop Master Integrals for $q \bar{q} \to V V$Apr 18 2014Jun 12 2014We compute the full set of two-loop Feynman integrals appearing in massless two-loop four-point functions with two off-shell legs with the same invariant mass. These integrals allow to determine the two-loop corrections to the amplitudes for vector boson ... More
Top-bottom interference effects in Higgs plus jet production at the LHCMar 11 2017We compute next-to-leading order QCD corrections to the top-bottom interference contribution to H+j production at the LHC. To achieve this, we combine the recent computation of the two-loop amplitudes for gg -> Hg and qg -> Hq, performed in the approximation ... More
QCD corrections to vector boson pair production in gluon fusion including interference effects with off-shell Higgs at the LHCMay 15 2016We compute next-to-leading order (NLO) QCD corrections to the production of two massive electroweak bosons in gluon fusion. We consider both the prompt production process $gg \to VV$ and the production mediated by an exchange of an s-channel Higgs boson, ... More
Double-real contribution to the quark beam function at N$^{3}$LO QCDSep 17 2018Apr 10 2019We compute the master integrals required for the calculation of the double-real emission contributions to the matching coefficients of 0-jettiness beam functions at next-to-next-to-next-to-leading order in perturbative QCD. As an application, we combine ... More
JWST observations of stellar occultations by solar system bodies and ringsOct 22 2015Nov 24 2015In this paper we investigate the opportunities provided by the James Webb Space Telescope (JWST) for significant scientific advances in the study of solar system bodies and rings using stellar occultations. The strengths and weaknesses of the stellar ... More
Molecular gas in blue compact dwarf galaxiesMay 15 2000Blue compact dwarf galaxies (BCDGs) are currently undergoing strong bursts of star formation. Nevertheless, only a few of them have been clearly detected in CO, which is thought to trace the "fuel" of star formation: H_2. In this paper, we present a deep ... More
High-Q/V air-mode photonic crystal cavities at microwave frequenciesJan 28 2011We present results for a photonic microwave resonator designed and fabricated at 17.4GHz with a record high Quality factor (Q = 26,400) at room temperature over a mode volume smaller than one cubic wavelength. The cavity is uniquely designed to have its ... More
Magnus and Dyson Series for Master IntegralsJan 13 2014Jan 21 2014We elaborate on the method of differential equations for evaluating Feynman integrals. We focus on systems of equations for master integrals having a linear dependence on the dimensional parameter. For these systems we identify the criteria to bring them ... More
New Methods for Small Area Estimation with Linkage UncertaintyDec 07 2017In Official Statistics, interest for data integration has been increasingly growing, due to the need of extracting information from different sources. However, the effects of these procedures on the validity of the resulting statistical analyses has been ... More
Bottom-quark effects in Higgs production at intermediate transverse momentumApr 20 2018Oct 09 2018We provide a precise description of the Higgs boson transverse momentum distribution including top and bottom quark contributions, that is valid for transverse momenta in the range mb < pt < mt, where mb and mt are the bottom and top quark masses. This ... More
Update on the BINGO 21cm intensity mapping experimentOct 21 201621cm intensity mapping is a novel approach aimed at measuring the power spectrum of density fluctuations and deducing cosmological information, notably from the Baryonic Acoustic Oscillations (BAO). We give an update on the progress of BAO from Integrated ... More
PDE-Foam - a probability-density estimation method using self-adapting phase-space binningDec 04 2008Jul 22 2009Probability Density Estimation (PDE) is a multivariate discrimination technique based on sampling signal and background densities defined by event samples from data or Monte-Carlo (MC) simulations in a multi-dimensional phase space. In this paper, we ... More
A posteriori inclusion of parton density functions in NLO QCD final-state calculations at hadron colliders: The APPLGRID ProjectNov 16 2009A method to facilitate the consistent inclusion of cross-section measurements based on complex final-states from HERA, TEVATRON and the LHC in proton parton density function (PDF) fits has been developed. This can be used to increase the sensitivity of ... More
$W^+W^-$ production at hadron colliders in NNLO QCDAug 22 2014Charged gauge boson pair production at the Large Hadron Collider allows detailed probes of the fundamental structure of electroweak interactions. We present precise theoretical predictions for on-shell $W^+W^-$ production that include, for the first time, ... More
A ring system detected around the Centaur (10199) CharikloSep 25 2014Until now, rings have been detected in the Solar System exclusively around the four giant planets. Here we report the discovery of the first minor-body ring system around the Centaur object (10199) Chariklo, a body with equivalent radius 124$\pm$9 km. ... More
ZZ production at hadron colliders in NNLO QCDMay 09 2014Sep 04 2014We report on the first calculation of next-to-next-to-leading order (NNLO) QCD corrections to the inclusive production of ZZ pairs at hadron colliders. Numerical results are presented for pp collisions with centre-of-mass energy ($\sqrt{s}$) ranging from ... More
Self-induced decoherence in dense neutrino gasesJan 22 2007Dense neutrino gases exhibit collective oscillations where "self-maintained coherence" is a characteristic feature, i.e., neutrinos of different energies oscillate with the same frequency. In a non-isotropic gas, however, the flux term of the neutrino-neutrino ... More
Comment on Neutrino Radiative Decay Limits from the Infrared BackgroundAug 26 1998Recent observations of TeV gamma rays from distant sources provide new limits on the cosmic infrared background and thus on radiative decays of background neutrinos. I translate these limits into bounds on transition dipole moments and compare them with ... More
Astro-Particle PhysicsDec 31 1997Recent developments of those areas of astro-particle physics are discussed that were represented at the HEP97 conference. In particular, the current status of direct and indirect dark-matter searches and of TeV neutrino and gamma-ray astronomy will be ... More
Dark Matter: Motivation, Candidates and SearchesDec 29 1997The physical nature of most of the gravitating mass in the universe is completely mysterious. The astrophysical evidence for the presence of this dark matter and astrophysical constraints on its properties will be reviewed. The most popular dark-matter ... More
Internal mobility edge in doped graphene: frustration in a renormalized latticeJul 06 2007We show that an internal localization mobility edge can appear around the Fermi energy in graphene by introducing impurities in the split-band regimen, or by producing vacancies in the lattice. The edge appears at the center of the spectrum and not at ... More
Symmetry allowed, but unobservable, phases in renormalizable Gauge Field Theory ModelsMay 03 2004In Quantum Field Theory models with spontaneously broken gauge invariance, renormalizability limits to four the degree of the Higgs potential, whose minima determine the vacuum state at tree-level. In many models, this bound has the intriguing consequence ... More
Characteristic Polynomials of Complex Random Matrix ModelsDec 04 2002Dec 12 2002We calculate the expectation value of an arbitrary product of characteristic polynomials of complex random matrices and their hermitian conjugates. Using the technique of orthogonal polynomials in the complex plane our result can be written in terms of ... More
New Critical Matrix Models and Generalized UniversalityJan 21 2002Mar 06 2002We study a class of one-matrix models with an action containing nonpolynomial terms. By tuning the coupling constants in the action to criticality we obtain that the eigenvalue density vanishes as an arbitrary real power at the origin, thus defining a ... More
Macroscopic and Microscopic (Non-)Universality of Compact Support Random Matrix TheoryFeb 17 2000Jun 07 2000A random matrix model with a sigma-model like constraint, the restricted trace ensemble (RTE), is solved in the large-n limit. In the macroscopic limit the smooth connected two-point resolvent G(z,w) is found to be non-universal, extending previous results ... More
Non-Keplerian rotation in the nucleus of NGC 1068: evidence for a massive accretion disk?Nov 06 2002The nucleus of the Seyfert galaxy NGC 1068 is believed to host a supermassive black hole. Evidence for the presence of a massive central object is provided by water maser emission, which displays a linear pattern in the sky, suggestive of a rotating disk. ... More
A class of self-gravitating accretion disksAug 09 1999We consider a class of steady-state self-gravitating accretion disks for which efficient cooling mechanisms are assumed to operate so that the disk is self-regulated at a condition of approximate marginal Jeans stability. In an earlier paper, this scenario ... More
Delocalised states in a 1D diagonally disordered systemOct 07 20031D diagonally disordered chain with Frenkel exciton and long range exponential intersite interaction is considered. It is shown that some states of this disordered system are delocalised contrary to the popular statement that all states in 1D disordered ... More
The resonant behaviour of the Faraday rotation in a medium with linear birefringenceJul 29 2004It is shown that the monochromatic optical wave propagating through the medium with linear birefringence in presence of a signal electromagnetic wave (whose wavelength is equal to the polarization beats length), displays Faraday rotation having the frequency ... More
Exponential Convergence of Cellular Dynamical Mean Field Theory: Reply to the comment by K. Aryanpour, Th. Maier and M. Jarrell (cond-mat/0301460)Apr 22 2004We reply to the comment by K. Aryanpour, Th. Maier and M. Jarrell (cond-mat/0301460) on our paper (Phys. Rev. B {\bf 65} 155112 (2002)). We demonstrate using general arguments and explicit examples that whenever the correlation length is finite, local ... More
QCD non-leading corrections to weak decays in the dimensional schemeOct 06 1992We compute the next to leading QCD corrections to weak four fermion interactions introducing a scheme that does not require an explicit definition of $\gamma_5$ in $d$ dimensions. This scheme reduces greatly the difficulties in calculating the two loop ... More
Unstable Heavy Majorana Neutrinos and LeptogenesisDec 22 1999May 15 2000We propose a new mechanism producing a non-vanishing lepton number asymmetry, based on decays of heavy Majorana neutrinos. If they are produced out of equilibrium, as occurs in preheating scenario, and are superpositions of mass eigenstates rapidly decaying, ... More
Twisted symmetries and integrable systemsFeb 07 2010Symmetry properties are at the basis of integrability. In recent years, it appeared that so called "twisted symmetries" are as effective as standard symmetries in many respects (integrating ODEs, finding special solutions to PDEs). Here we discuss how ... More
Statistics of weighted Poisson events and its applicationsSep 05 2013The statistics of the sum of random weights where the number of weights is Poisson distributed has important applications in nuclear physics, particle physics and astrophysics. Events are frequently weighted according to their acceptance or relevance ... More
Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev ModelsSep 26 2008Dec 04 2008We study the magnetic interactions in Mott-Hubbard systems with partially filled $t_{2g}$-levels and with strong spin-orbit coupling. The latter entangles the spin and orbital spaces, and leads to a rich variety of the low energy Hamiltonians that extrapolate ... More
Spin, Orbital and Charge Order at the Interface between Correlated OxidesApr 24 2008Nov 13 2008The collective behavior of correlated electrons in the VO$_2-$interface layer of LaVO$_3$/SrTiO$_3$ heterostructure is studied within a quarter-filled $t_{2g}$-orbital Hubbard model on a square lattice. We argue that the ground state is ferromagnetic ... More