Results for "Giulia Semeghini"

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Generation and manipulation of Schrödinger cat states in Rydberg atom arraysMay 14 2019May 15 2019Quantum entanglement involving coherent superpositions of macroscopically distinct states is among the most striking features of quantum theory, but its realization is challenging, since such states are extremely fragile. Using a programmable quantum ... More
Collisions of self-bound quantum dropletsDec 21 2018We report on the study of binary collisions between quantum droplets formed by an attractive mixture of ultracold atoms. We distinguish two main outcomes of the collision, i.e. merging and separation, depending on the velocity of the colliding pair. The ... More
Universality of the three-body Efimov parameter at narrow Feshbach resonancesMar 15 2013We measure the critical scattering length for the appearance of the first three-body bound state, or Efimov three-body parameter, at seven different Feshbach resonances in ultracold 39K atoms. We study both intermediate and narrow resonances, where the ... More
Measurement of the mobility edge for 3D Anderson localizationApr 14 2014Anderson localization is a universal phenomenon affecting non-interacting quantum particles in disorder. In three spatial dimensions it becomes particularly interesting to study because of the presence of a quantum phase transition from localized to extended ... More
Semileptonic and leptonic $B$ decays, circa 2016Oct 14 2016We summarize the status of semileptonic and leptonic $B$ decays, including $|V_{cb}|$ and $|V_{ub}|$ exclusive and inclusive determinations, decays to excited states of the charm meson spectrum and decays into $\tau$ leptons.
Determination of the CKM matrix elements |V(xb)|May 13 2013Jul 08 2013We review the current status of |V(cb)|, |V(ub)| and |V(tb)|, the absolute values of the matrix elements in the CKM third column.
Magnitudes of V(xb) CKM matrix elementsJun 05 2013Jul 08 2013We review the current status of the absolute values of the CKM matrix elements V(xb), with particular attention to latest determinations.
Threshold resummed spectra in semi-inclusive B decaysJul 05 2006I discuss some aspects of the universality of soft gluon dynamics in semileptonic and radiative decays at the threshold region.
Electroweak Physics Results at CDF Run IIMay 19 2004The Run II physics program of CDF is proceeding with approximately 200 pb-1 of analysis quality data collected at the center-of-mass energy of 1.96 TeV. The Electroweak measurements are among the first and most important benchmarks towards the best understanding ... More
Accurate predictions for heavy quark jetsMay 14 2007Heavy-flavour jets enter many of today's collider studies, yet NLO predictions for these quantities are subject to large uncertainties, larger than the corresponding experimental errors. We propose a new, infrared safe definition of heavy-quark jets which ... More
Resummed event shapes at hadron collidersOct 04 2004We present recently defined jet-observables for hadron-hadron dijet production, which are designed to reconcile the seemingly conflicting theoretical requirement of globalness, which makes it possible to resum them (automatically) at NLL accuracy and ... More
Basic Logic and Quantum Computing: Logical Judgements by an Insider ObserverJul 07 2004We consider the logical assertions of a hypothetical observer who is inside a quantum computer and performs a reversible quantum measurement, obtaining a symmetric couple of new axioms, valid only inside the quantum computer. The result is that, in this ... More
Automated resummation of jet observables in QCDAug 29 2003We present a master formula, with applicability conditions, which allows us to automate the resummation of infrared and collinear logarithms appearing in distributions of jet observables in QCD at next-to-leading logarithmic accuracy.
Theoretical Review of Radiative Rare B DecaysOct 30 1995A status report on the theory of radiative rare $B$ decays in the standard model is presented, with focus on inclusive decays $B \rightarrow X_{(s,d)}\, \gamma$ and exclusive decays $B \rightarrow (K^\ast,\omega,\rho) \, \gamma$. CP asymmetries are also ... More
Short and Long Distance Interplay in Inclusive $ B \to X_d γ$ DecaysFeb 13 1995Jun 29 1995We analyze the short and long distance contributions to inclusive $B \rightarrow X_d \gamma$ decay, paying particular attention to the dependence on the Cabibbo-Kobayashi-Maskawa parameter $V_{td}$. We discuss penguin diagrams with internal $u$ and $c$ ... More
Quaternionic Hankel operators and approximation by slice regular functionsJan 09 2015In this paper we study Hankel operators in the quaternionic setting. In particular we prove that they can be exploited to measure the $L^{\infty}$ distance of a slice $L^{\infty}$ function from the space of bounded slice regular functions.
The base change of the monodromy group for geometric Tannakian pairsJan 25 2016We prove that in any characteristic the formation of the monodromy group of a $\mathscr{D}$-module commutes with the extension of the ground field, extending a result of Gabber for separable extensions.
A theory of Galois descent for finite inseparable extensionsSep 17 2015Oct 22 2015We present a generalization of Galois descent to finite modular normal field extension $L/K$, using the Heerma-Galois group $Aut(L[\bar{X}]/K[\bar{X}])$ where $L[\bar{X}]=L[X]/(X^{p^e})$ and $e$ is the exponent of $L$ over $K$.
A microsimulation of traders activity in the stock market: the role of heterogeneity, agents' interactions and trade frictionsMay 13 1999Jul 25 2000We propose a model with heterogeneous interacting traders which can explain some of the stylized facts of stock market returns. In the model synchronization effects, which generate large fluctuations in returns, can arise either from an aggregate exogenous ... More
Scaling and Multi-scaling in Financial MarketsJul 25 2000This paper reviews some of the phenomenological models which have been introduced to incorporate the scaling properties of financial data. It also illustrates a microscopic model, based on heterogeneous interacting agents, which provides a possible explanation ... More
Supersymmetry results at the TevatronMay 17 2005The Run II physics programme of the Tevatron is proceeding with more than 300 pb-1 of analysis quality data, collected at a centre-of-mass energy of 1.96 TeV. Searches for supersymmetric particles are starting to set new limits, improving over the LEP ... More
Semileptonic B and D decays-latest developmentsSep 25 2012Oct 17 2012Semileptonic B and D decays are on a well deserved podium to extract CKM matrix elements, to validate theoretical tools and, more recently, even to look for hints of new physics. Here we review the latest updates.
Radiative and semileptonic B meson decay spectraAug 19 2006We review semi-inclusive charmless B decays, focussing on threshold logarithmic resumming and on universality of QCD dynamics in radiative and semileptonic decays.
Automated resummation of final state observables in QCDMay 15 2003We present an innovative method to resum infrared and collinear logarithms appearing in distributions of jet observables in QCD. The method, based on a general master formula with applicability conditions, allows resummations at next-to-leading logarithmic ... More
Gieseker conjecture for homogeneous spacesDec 07 2016We prove Gieseker conjecture for an homogeneous space $X$, saying that if $X$ has no non-trivial tame coverings then it has no non-trivial regular singular $\mathscr{O}_X$-coherent $\mathscr{D}_{X/k}$-modules. In order to do so we prove a K\"unneth formula ... More
Bayesian approach to LR assessment in case of rare type match: careful derivation and limitsFeb 09 2015Apr 13 2016The likelihood ratio (LR) is largely used to evaluate the relative weight of forensic data regarding two hypotheses and for its assessment Bayesian methods are widespread in the forensic field. However, the Bayesian `recipe' for the LR presented in most ... More
QCD and High Energy Interactions: Moriond 2015 Theory SummaryJul 07 2015I will summarise the new theory developments that emerged during the 2015 QCD Moriond conference. I will give my perspective on some of the topics and emphasise what I consider most relevant.
Quantum states as virtual singletons: converting duality into symmetryApr 09 2013In a predicative framework from basic logic, defined for a model of quantum parallelism by sequents, we characterize a class of first order domains, termed {\em virtual singletons}, which allows a generalization of the notion of duality, termed {\em symmetry}. ... More
Semileptonic B decaysJan 18 2013We review recent progress in exclusive B --> D^(*) and inclusive B --> X(u) semileptonic B decays
Semileptonic D decays and eta-eta^prime mixingSep 15 2012Dec 27 2012We discuss the impact of recent progress in semileptonic D decays on light flavour spectroscopy and estimate mixing parameters in the eta-eta^prime system.
Quaternionic Hankel operators and approximation by slice regular functionsJan 09 2015Nov 15 2016In this paper we study Hankel operators in the quaternionic setting. In particular we prove that they can be exploited to measure the $L^{\infty}$ distance of a slice $L^{\infty}$ function from the space of bounded slice regular functions.
The variation of the monodromy group in families of stratified bundles in positive characteristicMay 20 2014Jan 05 2015In this article we study smooth families of stratified bundles in positive characteristic and the variation of their monodromy group.Our aim is, in particular, to strengthen the weak form of the positive equicharacteristic $p$-curvature conjecture stated ... More
Non parametric Bayesian approach to LR assessment in case of rare haplotype matchJun 28 2015Sep 18 2015The evaluation of a match between the DNA profile of a stain found on a crime scene and that of a suspect (previously identified) involves the use of the unknown parameter $p=(p_1, p_2, ...)$, (the ordered vector which represents the proportions of the ... More
QCD and Collider ProcessesJan 18 2012Jan 24 2012I review the status of today's theoretical description of Standard Model processes relevant for Tevatron and LHC analyses, and of the tools that are used in phenomenological studies. I will also discuss a few recent ideas to further refine our abilities ... More
Studies of Open Charm and Charmonium Production at LHCbAug 23 2010We present recent results from charmonium and open charm production at the LHCb experiment at CERN, Geneva. We concentrate on studies for the measurement of the cross section pp ->JPsi+X in its decay channel with two muons, showing the agreement of the ... More
Sublinear Growth of Information in DNA SequencesFeb 27 2004We introduce a novel method to analyse complete genomes and recognise some distinctive features by means of an adaptive compression algorithm, which is not DNA-oriented. We study the Information Content as a function of the number of symbols encoded by ... More
Seminumerical resummation of event shapes and jet ratesMay 13 2002May 15 2002For many observables, the most difficult part of a single logarithmic resummation is the analytical treatment of the observable's dependence on multiple emissions. We present a general numerical method, which allows the resummation specifically of these ... More
Impact of model choice on LR assessment in case of rare haplotype match (frequentist approach)Feb 13 2015Apr 13 2016The likelihood ratio (LR) measures the relative weight of forensic data regarding two hypotheses. Several levels of uncertainty arise if frequentist methods are chosen for its assessment: the assumed population model only approximates the true one and ... More
Relative compactified Jacobians of linear systems on Enriques surfacesOct 28 2012Jan 18 2016We study certain moduli spaces of sheaves on Enriques surfaces thereby obtaining, in every odd dimension, new examples of Calabi--Yau manifolds. We describe the geometry (canonical bundle, fundamental group, second Betti number and certain Hodge numbers) ... More
Status of $|V_{cb}|$ and $|V_{ub}|$ CKM matrix elementsDec 13 2014We summarize the status of $|V_{cb}|$ and $|V_{ub}|$ determinations, including the long standing tension among exclusive and inclusive determinations. We also discuss $B$ meson semileptonic decays to excited states of the charm meson spectrum and leptonic ... More
Brief review on semileptonic B decaysSep 06 2012Oct 05 2012We concisely review semileptonic B decays, focussing on recent progress on both theoretical and experimental sides.
Characterization of quantum states in predicative logicFeb 08 2011Jul 15 2011We develop a characterization of quantum states by means of first order variables and random variables, within a predicative logic with equality, in the framework of basic logic and its definitory equations. We introduce the notion of random first order ... More
CP violation with BsMay 12 2012The observation of CP violation effects is becoming more and more significant in a variety of channels, due to the impressive experimental effort of the last years. We review recent progress in Bs semileptonic decays and in Bs decays into CP eigenstates. ... More
Effective theory approach to unstable particlesMay 13 2004May 27 2004We present a novel treatment of resonant massive particles appearing as intermediate states in high energy collisions. The approach uses effective field theory methods to treat consistently the instability of the intermediate resonant state. As a result ... More
A dynamical approach to semi-inclusive B decaysNov 30 2006Dec 22 2006A dynamical approach to semi-inclusive decays based on an effective running coupling for the strong interactions is described.
Progress on semi-leptonic $B_{(s)}$ decaysMar 30 2014May 25 2014We report on the current status of semi-leptonic $B_{(s)}$ decays, including rare decays, and the extraction of the absolute values of the CKM matrix elements $|V_{cb}|$ and $|V_{ub}|$.
A classification of certain almost $α$-Kenmotsu manifoldsJun 24 2010We study $\mathcal D$-homothetic deformations of almost $\alpha$-Kenmotsu structures. We characterize almost contact metric manifolds which are $CR$-integrable almost $\alpha$-Kenmotsu manifolds, through the existence of a canonical linear connection, ... More
The normal hull and commutator group for nonconnected group schemesMar 19 2018In this short note, we prove that there is a well behaved notion of normal hull for smooth algebraic group schemes over a field and that the commutator group $(G,H)$ is well defined for $H\subset G$ smooth, even when both of them are not connected.
The Casas-Alvero conjectureNov 16 2015Nov 19 2015We present a proof of the Casas-Alvero conjecture, stating that if a complex polynomial has a root in common with each of its derivatives it must be a multiple of the power of some monomial.
Relative compactified Jacobians of linear systems on Enriques surfacesOct 28 2012May 08 2019We study certain moduli spaces of sheaves on Enriques surfaces thereby obtaining, in every odd dimension, new examples of Calabi-Yau manifolds. We describe the geometry (canonical bundle, fundamental group, second Betti number and certain Hodge numbers) ... More
Electroweak W+W-jj prodution at NLO in QCD matched with parton shower in the POWHEG-BOXJan 08 2013We present an implementation of electroweak W+W-jj production at hadron colliders in the POWHEG framework, a method that allows the interfacing of a next-to-leading order QCD calculation with parton shower Monte Carlo programs. We provide results for ... More
Irreversible Evolution of a Wave Packet in The Rigged Hilbert Space Quantum MechanicsJul 27 2016Aug 10 2016It is well known that a state with complex energy cannot be the eigenstate of a self-adjoint operator, like the Hamiltonian. Resonances, i.e. states with exponentially decaying observables, are not vectors belonging to the conventional Hilbert space. ... More
A tale of two cones: the Higgs Branch of Sp(n) theories with 2n flavoursSep 21 2016The purpose of this short note is to highlight a particular phenomenon which concerns the Higgs branch of a certain family of 4d N = 2 theories with SO(2N) flavour symmetry. By studying the Higgs branch as an algebraic variety through Hilbert series techniques ... More
Observations from LHC proton-proton operationSep 18 2014This paper describes two distinct effects observed during the operation of the LHC in 2012: first, the impacts on beam parameter evolution of the end-of-squeeze instabilities encountered in the second half of the 2012 run; and, second, the very reproducible ... More
Two Photon Width of eta_c (paper version)Apr 18 2002We discuss the measured partial width of the pseudoscalar charmonium state eta_c into two photons. Predictions from potential models are examined and compared with experimental values. Including radiative corrections, it is found that present measurements ... More
Computational information for the logistic map at the chaos thresholdFeb 26 2001Jul 24 2001We study the logistic map $f(x)=\lambda x(1-x)$ on the unit square at the chaos threshold. By using the methods of symbolic dynamics, the information content of an orbit of a dynamical system is defined as the Algorithmic Information Content (AIC) of ... More
Features of Kamiokande-II, IMB and Baksan observations and their interpretation in a two-component model for the signalOct 02 2008We consider the time, angular and energy distributions of SN1987A events discussing the quality of their agreement with the expectations. A global interpretation is performed considering a simple model, based on the standard scenario for the explosion. ... More
Effectiveness of Measures of Performance During Speculative BubblesSep 15 2007Statistical analysis of financial data most focused on testing the validity of Brownian motion (Bm). Analysis performed on several time series have shown deviation from the Bm hypothesis, that is at the base of the evaluation of many financial derivatives. ... More
Socioeconomic Networks with Long-Range InteractionsJun 01 2007May 29 2008We study a modified version of a model previously proposed by Jackson and Wolinsky to account for communicating information and allocating goods in socioeconomic networks. In the model, the utility function of each node is given by a weighted sum of contributions ... More
Model risk in mean-variance portfolio selection: an analytic solution to the worst-case approachFeb 18 2019In this paper we consider the worst-case model risk approach described in Glasserman and Xu (2014). Portfolio selection with model risk can be a challenging operational research problem. In particular, it presents an additional optimisation compared to ... More
Slice-Polynomial Functions and Twistor Geometry of Ruled Surfaces in $\mathbb{CP}^3$Dec 28 2017In the present paper we introduce the class of slice-polynomial functions: slice regular functions {defined over the quaternions, outside the real axis,} whose restriction to any complex half-plane is a polynomial. These functions naturally emerge in ... More
Octahedralizing 3-colorable 3-polytopesMar 25 2019We investigate the question of whether any $d$-colorable simplicial $d$-polytope can be octahedralized, i.e., it can be subdivided to a $d$-dimensional geometric cross-polytopal complex. We give a positive answer in dimension $3$, with the additional ... More
Biothermoeconomics analysis of cyanobacteria and microalga use for sustainable biofuelSep 22 2017Exergy is a thermodynamic quantity useful to obtain information on the work from any process. The analyses of irreversibility are important in the designing and development of the productive processes for the economic growth, but they play a fundamental ... More
Patterns of consumption in socio-economic models with heterogeneous interacting agentsSep 09 1999We study consumption behaviour in systems with heterogeneous interacting agents. Two different models are introduced, respectively with long and short range interactions among agents. At any time step an agent decides whether or not to consume a good, ... More
On the quantum mechanical three-body problem with zero-range interactionsJan 29 2016In this note we discuss the quantum mechanical three-body problem with pairwise zero-range interactions in dimension three. We review the state of the art concerning the construction of the corresponding Hamiltonian as a self-adjoint operator in the bosonic ... More
Birth of colliding beams in Europe, two photon studies at AdoneNov 02 2015This article recalls the birth of the first electron-positron storage ring AdA, and the construction of the higher energy collider ADONE, where early photon-photon collisions were observed. The events which led the Austrian physicist Bruno Touschek to ... More
The diffuse supernova neutrino background: Expectations and uncertainties derived from SN1987AFeb 02 2011Context: The detection of the diffuse supernova neutrino background may be imminent, but theoretical predictions are affected by substantial uncertainties. AIMS. We calculate the signal and its uncertainty with the present configuration of Super-Kamiokande ... More
A model for next-to-leading order threshold resummed form factorsJul 20 2004Nov 23 2004We present a model for next-to-leading order resummed threshold form factors based on a time-like coupling recently introduced in the framework of small x physics. Improved expressions for the form factors in N-space are obtained which are not plagued ... More
The structure function of semi-inclusive heavy flavour decays in field theoryMar 15 2000Sep 20 2000We consider the decay of a heavy flavour into an inclusive hadronic state X of invariant mass m_X small with respect to its energy E_X, m_X << E_X. The electron spectrum and the hadronic mass distribution in semileptonic b -> u decays, or the photon spectrum ... More
On the maximum drawdown during speculative bubblesJul 27 2006Nov 03 2006A taxonomy of large financial crashes proposed in the literature locates the burst of speculative bubbles due to endogenous causes in the framework of extreme stock market crashes, defined as falls of market prices that are outlier with respect to the ... More
Relativistic compatibility of the interacting $κ$-Poincaré model and implications for the relative locality frameworkMar 11 2019We investigate the relativistic properties under boost transformations of the $\kappa$-Poincar\'e model with multiple causally connected interactions, both at the level of its formulation in momentum space only and when it is endowed with a full phase ... More
Representations of Affine Group Schemes Over General RingsJul 03 2018Aug 07 2018Among all affine, flat, finitely presented group schemes, we focus on those that are pure, this includes all groups which are extensions of a finite locally free group by a group with connected fibres. We prove that over an arbitrary base ring, pure group ... More
A continuum model of skeletal muscle tissue with loss of activationJan 26 2017We present a continuum model for the mechanical behavior of the skeletal muscle tissue when its functionality is reduced due to aging. The loss of ability of activating is typical of the geriatric syndrome called sarcopenia. The material is described ... More
Dynamical phase transition in the 1D-transverse field Ising chain characterized by the transverse magnetization spectral functionMar 08 2019We study a 1D-Quantum Ising Model in transverse field driven out of equilibrium by performing a composite quantum quench to deduce the asymptotic properties of the transverse magnetization stationary state via the analysis of the spectral function. What ... More
Contraction and regularizing properties of heat flows in metric measure spacesApr 22 2019We illustrate some novel contraction and regularizing properties of the Heat flow in metric-measure spaces that emphasize an interplay between Hellinger-Kakutani, Kantorovich-Wasserstein and Hellinger-Kantorvich distances. Contraction properties of Hellinger-Kakutani ... More
Invariant metrics for the quaternionic Hardy spaceDec 20 2013Dec 23 2013Riemannian metrics on the unit ball of the quaternions, which are naturally associated with the reproducing kernel Hilbert spaces. We study the metric arising from the Hardy space in detail. We show that, in contrast to the one-complex variable case, ... More
Singularities of moduli spaces of sheaves on K3 surfaces and Nakajima quiver varietiesMay 04 2015Mar 10 2018The aim of this paper is to study the singularities of certain moduli spaces of sheaves on K3 surfaces by means of Nakajima quiver varieties. The singularities in question arise from the choice of a non--generic polarization, with respect to which we ... More
Generalizations of 3-Sasakian manifolds and skew torsionApr 18 2018In the first part, we define and investigate new classes of almost 3-contact metric manifolds, with two guiding ideas in mind: first, what geometric objects are best suited for capturing the key properties of almost 3-contact metric manifolds, and second, ... More
On the modeling of internal parameters in hyperelastic biological materialsSep 28 2016This paper concerns the behavior of hyperelastic energies depending on an internal parameter. First, the situation in which the internal parameter is a function of the gradient of the deformation is presented. Second, two models where the parameter describes ... More
Constraints on cosmological birefringence energy dependence from CMB polarization dataNov 14 2012Feb 15 2013We study the possibility of constraining the energy dependence of cosmological birefringence by using CMB polarization data. We consider four possible behaviors, characteristic of different theoretical scenarios: energy-independent birefringence motivated ... More
Relative Locality in $κ$-PoincaréJun 28 2011Jul 03 2013We show that the $\kappa$-Poincar\'e Hopf algebra can be interpreted in the framework of curved momentum space leading to the relativity of locality \cite{AFKS}. We study the geometric properties of the momentum space described by $\kappa$-Poincar\'e, ... More
Two photon width of eta_cOct 16 2001We discuss the measured partial width of the pseudoscalar charmonium state, $\eta_c$, into two photons. Predictions from potential models are examined and compared with experimental values. Including radiative corrections, it is found that present measurements ... More
Non-perturbative effects in e^+e^- event-shape variablesJun 21 2001We review theoretical methods employed to study non-perturbative contributions to e^+e^- event-shapes and discuss their phenomenological relevance.
Perturbative QCD analysis of near-to-planar three jet eventsOct 06 2000We present the all-order resummed thrust minor distribution as a measure of aplanarity in three-jet events.
Supermassive black holes and their host spheroids III. The $M_{BH} - n_{sph}$ correlationMar 07 2016The S\'ersic $R^{1/n}$ model is the best approximation known to date for describing the light distribution of stellar spheroidal and disk components, with the S\'ersic index $n$ providing a direct measure of the central radial concentration of stars. ... More
Gravitons that shake handsOct 18 2016We examine some of the roots of parity violation for gravitons and uncover a closely related new effect: correlations between right and left handed gravitons. Such correlators have spin 4 if they involve gravitons moving along the same direction, and ... More
NLO corrections to electroweak and QCD production of W+W+ plus two jets in the POWHEGBOXAug 03 2011Dec 15 2011We present the matching of the next-to-leading order QCD calculation for W+W+jj production via vector-boson fusion in hadronic collisions to parton-shower Monte-Carlo programs according to the POWHEG method. Our implementation complements existing code ... More
Shift invariant subspaces of slice $L^2$ functionsFeb 07 2018In this paper we characterize the closed invariant subspaces for the ($*$-)multiplier operator of the quaternionic space of slice $L^2$ functions. As a consequence, we obtain the inner-outer factorization theorem for the quaternionic Hardy space on the ... More
Singularities of moduli spaces of sheaves on K3 surfaces and Nakajima quiver varietiesMay 04 2015Jan 18 2016The aim of this paper is to study the singularities of certain moduli spaces of sheaves on K3 surfaces by means of Nakajima quiver varieties. The singularities in question arise from the choice of a non--generic polarization, with respect to which we ... More
The impact of baryonic physics on the subhalo mass function and implications for gravitational lensingAug 24 2016We investigate the impact of baryonic physics on the subhalo population by analyzing the results of two recent hydrodynamical simulations (EAGLE and Illustris), which have very similar configuration, but a different model of baryonic physics. We concentrate ... More
Correlation between opposite-helicity gravitons: Imprints on gravity-wave and microwave backgroundsOct 18 2016Jan 13 2017We examine some of the roots of parity violation for gravitons and uncover a closely related new effect: correlations between right and left handed gravitons. Such correlators have spin 4 if they involve gravitons moving along the same direction, and ... More
Reappraisal of a model for deformed special relativityDec 10 2015We revisit one of the earliest proposals for deformed dispersion relations in the light of recent results on dynamical dimensional reduction and production of cosmological fluctuations. Depending on the specification of the measure of integration and ... More
The Mittag-Leffler Theorem for regular functions of a quaternionic variableNov 14 2017We prove a version of the classical Mittag-Leffler Theorem for regular functions over quaternions. Our result relies upon an appropriate notion of principal part, that is inspired by the recent definition of spherical analyticity.
Landau-Toeplitz theorems for slice regular functions over quaternionsApr 11 2014The theory of slice regular functions of a quaternionic variable extends the notion of holomorphic function to the quaternionic setting. This theory, already rich of results, is sometimes surprisingly different from the theory of holomorphic functions ... More
Hyperelliptic Integrals and Mirrors of the Johnson-Kollár del Pezzo SurfacesJan 25 2019For all k>0 integer, we consider the regularised I-function of the family of del Pezzo surfaces of degree 8k+4 in P(2,2k+1,2k+1, 4k+1), first constructed by Johnson and Koll\'ar. We show that this function, which is of hypergeometric type, is a period ... More
Hollow polytopes of large widthDec 03 2018We construct a hollow lattice polytope (resp. a hollow lattice simplex) of dimension $14$ (resp.$~404$) and of width $15$ (resp.$~408$). They are the first known hollow lattice polytopes of width larger than dimension. We also construct a hollow (non-lattice) ... More
Bruno Touschek and AdA: from Frascati to Orsay. In memory of Bruno Touschek, who passed away 40 years ago, on May 25th, 1978May 23 2018Jun 06 2018The first electron-positron collisions in a laboratory were observed in 1963-1964 at the Laboratoire de l'Acc\'el\'erateur Lin\'eaire d'Orsay, in France, with the storage ring AdA, which had been constructed in the Italian National Laboratories of Frascati ... More
From Hankel operators to Carleson measures in a quaternionic variableJul 31 2014We introduce and study Hankel operators defined on the Hardy space of regular functions of a quaternionic variable. Theorems analogous to those of Nehari anc C. Fefferman are proved.
A Comparison of High-Frequency Cross-Correlation MeasuresFeb 19 2004On a high-frequency scale the time series are not homogeneous, therefore standard correlation measures can not be directly applied to the raw data. There are two ways to deal with this problem. The time series can be homogenised through an interpolation ... More
Patterns of consumption in a discrete choice model with asymmetric interactionsOct 30 2000Oct 31 2000We study the consumption behaviour of an asymmetric network of heterogeneous agents in the framework of discrete choice models with stochastic decision rules. We assume that the interactions among agents are uniquely specified by their ``social distance'' ... More