Results for "Silvia Bianchi"

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Some advances on the set covering polyhedron of circulant matricesMay 28 2012Working on the set covering polyhedron of consecutive ones circulant matrices, Argiroffo and Bianchi found a class of facet defining inequalities, induced by a particular family of circulant minors. In this work we extend these results to inequalities ... More
On dominating set polyhedra of circular interval graphsDec 19 2017Feb 20 2018Clique-node and closed neighborhood matrices of circular interval graphs are circular matrices. The stable set polytope and the dominating set polytope on these graphs are therefore closely related to the set packing polytope and the set covering polyhedron ... More
Circuits and circulant minorsFeb 08 2019Circulant contraction minors play a key role for characterizing ideal circular matrices in terms of minimally non ideal structures. In this article we prove necessary and sufficient conditions for a circular matrix $A$ to have circulant contraction minors ... More
ABJM amplitudes and WL at finite NJun 13 2013Jul 25 2013We evaluate ABJM observables at two loops, for any value of the rank N of the gauge group. We compute the color subleading contributions to the four-point scattering amplitude in ABJM at two loops. Contrary to the four dimensional case, IR divergent N-subleading ... More
The Conformal Manifold of Chern-Simons Matter TheoriesSep 30 2010Oct 25 2010We determine perturbatively the conformal manifold of N=2 Chern-Simons matter theories with the aim of checking in the three dimensional case the general prescription based on global symmetry breaking, recently introduced. We discuss in details few remarkable ... More
Minimally helicity violating, maximally simple scalar amplitudes in N=4 SYMAug 01 2012Nov 21 2012In planar N=4 SYM we study a particular class of helicity preserving amplitudes. These are scalar amplitudes whose flavor configuration is chosen in such a way that only a limited number of diagrams is allowed, which exhibit an iterative structure. For ... More
Infrared stability of ABJ-like theoriesOct 27 2009Nov 11 2009We consider marginal deformations of the superconformal ABJM/ABJ models which preserve N=2 supersymmetry. We determine perturbatively the spectrum of fixed points and study their infrared stability. We find a closed line of fixed points which is IR stable. ... More
An all order identity between ABJM and N=4 SYM four-point amplitudesDec 15 2011We derive an exact algebraic identity between the two-loop four-point amplitude in ABJM theory and the corresponding one-loop amplitude in N=4 SYM theory. This identity generalizes previous partial results to an exact relation valid at all orders in the ... More
Infrared Stability of N=2 Chern-Simons Matter TheoriesDec 22 2009Feb 04 2010According to the AdS4/CFT3 correspondence, N=2 supersymmetric Chern-Simons matter theories should have a stable fixed point in the infrared. In order to support this prediction we study RG flows of two-level Chern-Simons matter theories with/without flavors ... More
Determining QCD Low-Energy Couplings from lattice simulationsOct 12 2007Different strategies for the computation of QCD low-energy couplings by matching lattice QCD with the chiral effective theory are reviewed. After recalling the main features of the chiral effective theory in the epsilon- and p- regimes, the current status ... More
On the construction of variant supergravities in D=11, D=10Jul 09 2002We construct with a geometric procedure the supersymmetry transformation laws and Lagrangian for all the ``variant'' D=11 and D=10 Type IIA supergravities. We identify into our classification the D=11 and D=10 Type IIA ``variant'' theories first introduced ... More
Correctors and Field Fluctuations for the $p_ε(x)$-Laplacian with Rough Exponents: The Sublinear Growth CaseJul 15 2011Jun 14 2012A corrector theory for the strong approximation of gradient fields inside periodic composites made from two materials with different power law behavior is provided. Each material component has a distinctly different exponent appearing in the constitutive ... More
The role of cluster age on the onset of multiple populations in stellar clustersJul 29 2019The origin of the chemical anomalies in star clusters is still an open question, although much effort has been employed both from a theoretical and observational point of view. The exploration of whether such multiple stellar populations are found based ... More
Detection of Gamma-Ray Bursts in the 1 GeV - 1 TeV energy range by ground based experimentsApr 23 1999Sep 29 1999Ground based extensive air showers arrays can observe GRBs in the 1-1000 GeV energy range using the "single particle" techique. The sensitivity to detect a GRB as a function of the burst parameters and the detector characteristics are discussed. The rate ... More
Finite dimensional representations of symplectic reflection algebras associated to wreath products IIJan 11 2005This note extends some results of a previous paper (math.RT/0403250) about finite dimensional representations of the wreath product symplectic reflection algebra H(k,c,N,G) of rank N attached to a finite subgroup G of SL(2,C) (here k is a number and c ... More
Modelling the Far-Infrared emission in spyral galaxiesNov 22 1999This thesis presents an original model for the FIR emission in spirals, developed from an existing radiative transfer code (Bianchi, Ferrara & Giovanardi, 1996, ApJ, 465, 127). The model's main features are: a complete treatment of multiple scattering ... More
Dust Extinction and Emission in a Clumpy Galactic Disk. An Application of the Radiative Transfer Code TRADINGJul 18 2008Jul 24 2008AIMS: I present the Monte Carlo radiative transfer code TRADING (Transfer of RAdiation through Dust In Galaxies). The code computes self-consistently the extinction of radiation in a dusty medium (including absorption and scattering) and the dust emission. ... More
Black hole entropy from graviton entanglementNov 02 2012Jan 07 2013We argue that the entropy of a black hole is due to the entanglement of matter fields and gravitons across the horizon. While the entanglement entropy of the vacuum is divergent because of UV correlations, we show that low-energy perturbations of the ... More
Black Hole Entropy, Loop Gravity, and Polymer PhysicsNov 25 2010Loop Gravity provides a microscopic derivation of Black Hole entropy. In this paper, I show that the microstates counted admit a semiclassical description in terms of shapes of a tessellated horizon. The counting of microstates and the computation of ... More
Braid groups, mapping class groups and their homology with twisted coefficientsJan 23 2019Jan 27 2019We consider the Birman-Hilden inclusion $\varphi\colon\mathfrak{Br}_{2g+1}\to\Gamma_{g,1}$ of the braid group into the mapping class group of an orientable surface with boundary, and prove that $\varphi$ is stably trivial in homology with twisted coefficients ... More
Homotopy type of symplectomorphism groups of S^2 X S^2Sep 25 2000May 02 2002In this paper we discuss the topology of the symplectomorphism group of a product of two 2-dimensional spheres when the ratio of their areas lies in the interval (1,2]. More precisely we compute the homotopy type of this symplectomorphism group and we ... More
Nonanticommutative U(1) SYM theories: Renormalization, fixed points and infrared stabilityApr 21 2009Renormalizable nonanticommutative SYM theories with chiral matter in the adjoint representation of the gauge group have been recently constructed in [arXiv:0901.3094]. In the present paper we focus on the U*(1) case with matter interacting through a cubic ... More
The 1/2 BPS Wilson loop in ABJ(M) at two loops: The detailsJul 02 2013Jul 14 2013We compute the expectation value of the 1/2 BPS circular Wilson loop operator in ABJ(M) theory at two loops in perturbation theory. Our result turns out to be in exact agreement with the weak coupling limit of the prediction coming from localization, ... More
Light-like Wilson loops in ABJM and maximal transcendentalityApr 22 2013We revisit the computation of the two-loop light-like tetragonal Wilson loop for three dimensional pure Chern-Simons and N=6 Chern-Simons-matter theory, within dimensional regularization with dimensional reduction scheme. Our examination shows that, contrary ... More
The 1/2 BPS Wilson loop in ABJM theory at two loopsMar 27 2013We compute the expectation value of the 1/2 BPS circular Wilson loop in ABJM theory at two loops in perturbation theory. The result shows perfect agreement with the prediction from localization and the proposed framing factor.
Lovász-Schrijver PSD-operator on Claw-Free GraphsDec 06 2016The subject of this work is the study of $\LS_+$-perfect graphs defined as those graphs $G$ for which the stable set polytope $\stab(G)$ is achieved in one iteration of Lov\'asz-Schrijver PSD-operator $\LS_+$, applied to its edge relaxation $\estab(G)$. ... More
The Minor inequalities in the description of the Set Covering Polyhedron of Circulant MatricesJun 06 2012In this work we give a complete description of the set covering polyhedron of circulant matrices $C^k_{sk}$ with $s = 2,3$ and $k\geq 3 $ by linear inequalities. In particular, we prove that every non boolean facet defining inequality is associated with ... More
Universality and scaling behavior of RG gauge actionsSep 04 2003We study universality and scaling properties of RG gauge actions (Iwasaki and DBW2). In the first part we consider the critical temperature T_{c} and compute the reference energy scale r_{0} for critical couplings \beta_{c} corresponding to N_{t}=3,4,6,8. ... More
N=1 domain wall solutions of massive type II supergravity and the issue of mirror symmetryJan 31 2007We report on Domain Wall solution of Calabi-Yau compactifications with general fluxes and their application to the study of mirror symmetry in generalized backgrounds. We address, in particular, to the issue of magnetic NSNS fluxes. We show that the Domain ... More
N=4 supergravity for Type IIB on T^6/Z_2 in presence of fluxesDec 16 2003Dec 22 2003We report on the construction of four dimensional gauged supergravity models that can be interpreted as type IIB orientifold compactification in presence of 3-form fluxes and D3--branes. We mainly address our attention to the symplectic embedding of the ... More
Universality and RG-improved gauge actionsAug 26 2002Aug 30 2002The reference energy scale r_0 is evaluated for RG-improved Iwasaki and DBW2 gauge actions (N_f = 0), at values of the deconfinement coupling beta_c corresponding to N_t = 3,4,6,8. The universality of r_0 T_c between Iwasa ki and Wilson action is confirmed; ... More
Asymptotics of the occupancy scheme in a random environment and its applications to triesSep 11 2016Aug 03 2017Consider $ m $ copies of an irreducible, aperiodic Markov chain $ Y $ taking values in a finite state space. The asymptotics as $ m $ tends to infinity, of the first time from which on the trajectories of the $ m $ copies differ, have been studied by ... More
Perturbation theory for string sigma modelsApr 06 2016Apr 07 2016In this thesis we investigate quantum aspects of the Green-Schwarz superstring in various AdS backgrounds relevant for the AdS/CFT correspondence, providing several examples of perturbative computations in the corresponding integrable sigma-models. We ... More
The length operator in Loop Quantum GravityJun 28 2008Sep 11 2008The dual picture of quantum geometry provided by a spin network state is discussed. From this perspective, we introduce a new operator in Loop Quantum Gravity - the length operator. We describe its quantum geometrical meaning and derive some of its properties. ... More
Splitting of the homology of the punctured mapping class groupMar 14 2019Let $\Gamma_{g,1}^m$ be the mapping class group of the orientable surface $\Sigma_{g,1}^m$ of genus $g$ with one parametrised boundary curve and $m$ permutable punctures; when $m=0$ we omit it from the notation. Let $\beta_{m}(\Sigma_{g,1})$ be the braid ... More
A combinatorial approach to Alexander-Hirschowitz Theorem based on toric degenerationsJul 21 2009May 26 2010We present an alternative proof of the Alexander-Hirschowitz Theorem in dimension 3 using degenerations of toric varieties.
Radiative Transfer in Spiral GalaxiesSep 16 2003The internal dust extinction in spiral galaxies can affect our understanding of their structure and morphology, as well as our perception of the distant universe in the background. The intrinsic properties of the stellar and dust components can be studied ... More
Loop Quantum Gravity a la Aharonov-BohmJul 24 2009Sep 10 2009The state space of Loop Quantum Gravity admits a decomposition into orthogonal subspaces associated to diffeomorphism equivalence classes of spin-network graphs. In this paper I investigate the possibility of obtaining this state space from the quantization ... More
Asymptotic properties of adaptive maximum likelihood estimators in latent variable modelsJun 25 2012Jul 04 2014Latent variable models have been widely applied in different fields of research in which the constructs of interest are not directly observable, so that one or more latent variables are required to reduce the complexity of the data. In these cases, problems ... More
The NA62 Experiment at CERNOct 01 2015Oct 19 2015The main physics goal of the NA62 experiment at CERN is to precisely measure the branching ratio of the kaon rare decay $K^+\rightarrow \pi^+ \nu \bar\nu$. This decay is strongly suppressed in the Standard Model and its branching ratio is theoretically ... More
Behavioural Types for Actor SystemsJun 08 2012Recent mainstream programming languages such as Erlang or Scala have renewed the interest on the Actor model of concurrency. However, the literature on the static analysis of actor systems is still lacking of mature formal methods. In this paper we present ... More
Prospects for an experiment to measure $BR(K_L\rightarrow π^0ν\barν)$ at the CERN SpSJul 23 2018We are investigating the feasibility of performing a measurement of $BR(K_L\rightarrow\pi^0\nu\bar\nu)$ using a high-energy secondary neutral beam at the CERN SPS in a successor experiment to NA62. The timescale would require many years; we assume that ... More
Umbral Calculus, a Different Mathematical LanguageFeb 24 2018This thesis is intended to provide an account of the theory and applications of Operational Methods that allow the "translation" of the theory of special functions and polynomials into a "different" mathematical language. The language we are referring ... More
Trakhtenbrot theorem and first-order axiomatic extensions of MTLMar 04 2014Jul 09 2014In 1950, B.A. Trakhtenbrot showed that the set of first-order tautologies associated to finite models is not recursively enumerable. In 1999, P. H\'ajek generalized this result to the first-order versions of \L ukasiewicz, G\"odel and Product logics. ... More
First-order Nilpotent Minimum Logics: first stepsMar 30 2011Jul 02 2012Following the lines of the analysis done in [BPZ07, BCF07] for first-order G\"odel logics, we present an analogous investigation for Nilpotent Minimum logic NM. We study decidability and reciprocal inclusion of various sets of first-order tautologies ... More
Vindicating single-T modified blackbody fits to Herschel SEDs (Research Note)Feb 22 2013I show here that the bulk of the dust mass in a galaxy can be equivalently estimated from: i) the full spectral energy distribution of dust emission, using the approach of Draine & Lee (2007) that includes a distribution of dust grains and a range of ... More
Ergodic convergence of a stochastic proximal point algorithmApr 21 2015Jul 25 2016The purpose of this paper is to establish the almost sure weak ergodic convergence of a sequence of iterates $(x_n)$ given by $x_{n+1} = (I+\lambda_n A(\xi_{n+1},\,.\,))^{-1}(x_n)$ where $(A(s,\,.\,):s\in E)$ is a collection of maximal monotone operators ... More
Misiurewicz parameters and dynamical stability of polynomial-like maps of large topological degreeDec 08 2016Given a family of polynomial-like maps of large topological degree, we relate the presence of Misiurewicz parameters to a growth condition of the postcritical volume. This allows us to generalize to this setting the theory of stability and bifurcation ... More
On some logical and algebraic properties of axiomatic extensions of the monoidal t-norm based logic MTL related with single chain completenessMay 21 2012In [Mon11] are studied, for the axiomatic extensions of the monoidal t-norm based logic ([EG01]), the properties of single chain completeness. On the other side, in [GJKO07, Chapter 5] are studied many logical and algebraic properties (like Halld\'en ... More
On the homology of the commutator subgroup of the pure braid groupMay 13 2019We study the homology of $[P_n,P_n]$, the commutator subgroup of the pure braid group on $n$ strands, and show that $H_l([P_n,P_n])$ contains a free abelian group of infinite rank for all $1\leq l\leq n-2$. As a consequence we determine the cohomological ... More
The Effects of Galaxy Shape and Rotation on the X-ray Haloes of Early-Type GalaxiesApr 15 2013May 20 2013We present a detailed diagnostic study of the observed temperatures of the hot X-ray coronae of early-type galaxies. By extending the investigation carried out in Pellegrini (2011) with spherical models, we focus on the dependence of the energy budget ... More
The effects of flattening and rotation on the temperature of the X-ray halos of elliptical galaxiesFeb 27 2013Elliptical galaxies have hot coronae with X-ray luminosities and mean gas temperatures that span over wide ranges. This variation can be partially due to the energy budget of the hot gas, that depends on the host galaxy structure and internal kinematics. ... More
A Direct Proof of Schwichtenberg's Bar Recursion Closure TheoremJul 18 2016In 1979 Schwichtenberg showed that a rule-like version Spector's bar recursion of lowest type levels $0$ and $1$ is closed under system $\text{T}$. More precisely, if the functional $Y$ which controls the stopping condition of Spector's bar recursor is ... More
Unveiling the thermal and magnetic map of neutron star surfaces though their X-ray emission: method and lightcurves analysisOct 24 2005Recent Chandra and XMM-Newton observations of a number of X-ray ``dim'' pulsating neutron stars revealed quite unexpected features in the emission from these sources. Their soft thermal spectrum, believed to originate directly from the star surface, shows ... More
A Logic for True ConcurrencyOct 18 2011Jan 17 2014We propose a logic for true concurrency whose formulae predicate about events in computations and their causal dependencies. The induced logical equivalence is hereditary history preserving bisimilarity, and fragments of the logic can be identified which ... More
Profiles of Strong Permitted Lines in Classical T Tauri StarsJan 18 2000We present a spectral analysis of 30 T Tauri stars observed with the Hamilton echelle spectrograph over more than a decade. One goal is to test magnetospheric accretion model predictions. Observational evidence previously published supporting the model, ... More
New Techniques for obtaining Schubert-type formulas for Hamiltonian manifoldsApr 26 2010Jul 27 2012In [GT], Goldin and the second author extend some ideas from Schubert calculus to the more general setting of Hamiltonian torus actions on compact symplectic manifolds with isolated fixed points. (See also [Kn99] and [Kn08].) The main goal of this paper ... More
The local power of the gradient testApr 30 2010Jul 12 2010The asymptotic expansion of the distribution of the gradient test statistic is derived for a composite hypothesis under a sequence of Pitman alternative hypotheses converging to the null hypothesis at rate $n^{-1/2}$, $n$ being the sample size. Comparisons ... More
New convergence results for the scaled gradient projection methodJun 25 2014Feb 26 2015The aim of this paper is to deepen the convergence analysis of the scaled gradient projection (SGP) method, proposed by Bonettini et al. in a recent paper for constrained smooth optimization. The main feature of SGP is the presence of a variable scaling ... More
Counting rises, levels, and drops in compositionsOct 14 2003A composition of $n\in\NN$ is an ordered collection of one or more positive integers whose sum is $n$. The number of summands is called the number of parts of the composition. A palindromic composition of $n$ is a composition of $n$ in which the summands ... More
On topological properties of positive complexity one spacesMay 30 2019Motivated by work of Fine and Panov, and of Lindsay and Panov, we prove that every closed symplectic complexity one space that is positive (e.g. positive monotone) enjoys topological properties that Fano varieties with a complexity one holomorphic torus ... More
Finite dimensional representations of symplectic reflection algebras associated to wreath productsMar 15 2004Jun 09 2004In this paper we construct finite dimensional representations of the wreath product symplectic reflection algebra H(k,c,N,G) of rank N attached to a finite subgroup G of SL(2,C) (here k is a number and c a class function on the set of nontrivial elements ... More
Quantum anomalies in A^{(1)}_r Toda theories with defectsFeb 27 2019We study quantum integrability of affine Toda theories with a line of defect. In particular, we focus on the problem of constructing quantum higher-spin conserved currents in models defined by two A_r^{(1)} Toda theories separated by a non-trivial tipe-I ... More
Linking Publications and Observations - the ESO Telescope BibliographyDec 22 2011Bibliometric studies have become increasingly important in evaluating individual scientists, specific facilities, and entire observatories. In this context, the ESO Library has developed and maintains two tools: FUSE, a full-text search tool, and the ... More
A study on users' privacy perception with smart devicesSep 02 2018Nowadays, privacy has become a very serious issue with smart and mobile platforms. Users tend to allow intrusive apps access much sensible information without really knowing the potential threats. To solve this issue several solutions (e.g. GDPR) have ... More
Operators ideals and approximation propertiesNov 30 2012Dec 13 2012We use the notion of $\A$-compact sets, which are determined by a Banach operator ideal $\A$, to show that most classic results of certain approximation properties and several Banach operator ideals can be systematically studied under this framework. ... More
On the vertices of indecomposable summands of certain Lefschetz modulesSep 27 2011We study the reduced Lefschetz module of the complex of p-radical and p-centric subgroups. We assume that the underlying group G has parabolic characteristic p and the centralizer of a certain noncentral p-element has a component with central quotient ... More
Operational vs. Umbral Methods and Borel TransformAug 12 2019Differintegral methods, currently exploited in calculus, provide a fairly unexhausted source of tools to be applied to a wide class of problems involving the theory of special functions and not only. The use of integral transforms of Borel type and the ... More
Weighted Quasi Interpolant Spline Approximation of 3D point clouds via local refinementJun 10 2019We present a new surface approximation, the Weighted Quasi Interpolant Spline Approximation (w-QISA), to approximate very large and noisy point clouds. We adopt local implicit representations based on three key ingredients: 1) a local mesh for the piecewise ... More
Convergence of a Multi-Agent Projected Stochastic Gradient Algorithm for Non-Convex OptimizationJul 13 2011Dec 02 2013We introduce a new framework for the convergence analysis of a class of distributed constrained non-convex optimization algorithms in multi-agent systems. The aim is to search for local minimizers of a non-convex objective function which is supposed to ... More
Horizon energy as the boost boundary term in general relativity and loop gravityMay 24 2012We show that the near-horizon energy introduced by Frodden, Ghosh and Perez arises from the action for general relativity as a horizon boundary term. Spin foam variables are used in the analysis. The result provides a derivation of the horizon boost Hamiltonian ... More
The perturbative Regge-calculus regime of Loop Quantum GravitySep 13 2007Dec 11 2007The relation between Loop Quantum Gravity and Regge calculus has been pointed out many times in the literature. In particular the large spin asymptotics of the Barrett-Crane vertex amplitude is known to be related to the Regge action. In this paper we ... More
Finite-dimensional representations of hyper multicurrent and multiloop algebrasMay 12 2019We investigate the categories of finite-dimensional representations of multicurrent and multiloop hyperalgebras in positive characteristic, i.e., the hyperalgebras associated to the multicurrent algebras $\mathfrak g\otimes\mathbb{C}[t_1,\ldots,t_n]$ ... More
Kicked neutron stars and microlensingSep 02 1996Due to the large kick velocities with which neutron stars are born in supernovae explosions, their spatial distribution is more extended than that of their progenitor stars. The large scale height of the neutron stars above the disk plane makes them potential ... More
A characteristic subgroup for fusion systemsNov 22 2008As a counterpart for the prime 2 to Glauberman's $ZJ$-theorem, Stellmacher proves that any nontrivial 2-group $S$ has a nontrivial characteristic subgroup $W(S)$ with the following property. For any finite $\Sigma_4$-free group $G$, with $S$ a Sylow 2-subgroup ... More
Some matrix nearness problems suggested by Tikhonov regularizationFeb 10 2016The numerical solution of linear discrete ill-posed problems typically requires regularization, i.e., replacement of the available ill-conditioned problem by a nearby better conditioned one. The most popular regularization methods for problems of small ... More
BPS Wilson loops and Bremsstrahlung function in ABJ(M): a two loop analysisFeb 17 2014Mar 11 2014We study a family of circular BPS Wilson loops in N=6 super Chern-Simons-matter theories, generalizing the usual 1/2-BPS circle. The scalar and fermionic couplings depend on two deformation parameters and these operators can be considered as the ABJ(M) ... More
Big Data Computing and Clouds: Trends and Future DirectionsDec 17 2013Aug 22 2014This paper discusses approaches and environments for carrying out analytics on Clouds for Big Data applications. It revolves around four important areas of analytics and Big Data, namely (i) data management and supporting architectures; (ii) model development ... More
Scattering Amplitudes/Wilson Loop Duality In ABJM TheoryJul 15 2011Oct 05 2011For N=6 superconformal Chern-Simons-matter theories in three dimensions, by a direct superspace Feynman diagram approach, we compute the two-loop four-point scattering amplitude with external chiral matter fields. We find that the result is in perfect ... More
One Loop Amplitudes In ABJMApr 19 2012Jul 10 2012For three dimensional N=6 superconformal field theories we compute one-loop scattering amplitudes for any number of external particles. We focus on a particular subsector of N=2 invariant superamplitudes for which the ordinary perturbative evaluation ... More
The quantum 1/2 BPS Wilson loop in ${\cal N}=4$ Chern-Simons-matter theoriesJun 22 2016In three dimensional ${\cal N}=4$ Chern-Simons-matter theories two independent fermionic Wilson loop operators can be defined, which preserve half of the supersymmetry charges and are cohomologically equivalent at classical level. We compute their three-loop ... More
A matrix model for the latitude Wilson loop in ABJM theoryFeb 21 2018Aug 13 2018In ABJ(M) theory, we propose a matrix model for the exact evaluation of BPS Wilson loops on a latitude circular contour, so providing a new weak-strong interpolation tool. Intriguingly, the matrix model turns out to be a particular case of that computing ... More
Framing and localization in Chern-Simons theories with matterApr 01 2016Jun 23 2016Supersymmetric localization provides exact results that should match QFT computations in some regularization scheme. The agreement is particularly subtle in three dimensions where complex answers from localization procedure sometimes arise. We investigate ... More
Towards the exact Bremsstrahlung function of ABJM theoryMay 30 2017We present the three-loop calculation of the Bremsstrahlung function associated to the 1/2-BPS cusp in ABJM theory, including color subleading corrections. Using the BPS condition we reduce the computation to that of a cusp with vanishing angle. We work ... More
Scattering in ABJ theoriesOct 04 2011We study the correspondence between scattering amplitudes and Wilson loops in three-dimensional Chern-Simons matter theories. In particular, using N=2 superspace formalism, we compute at one loop the whole spectrum of four-point superamplitudes for generic ... More
Attractive forces between circular polyions of the same chargeDec 19 2001We study two models of ringlike polyions which are two-dimensional versions of simple models for colloidal particles (model A) and for rodlike segments of DNA (model B), both in solution with counterions. The counterions may condensate on Z sites of the ... More
Recovering true metal abundances of the ICMJul 03 2001Recovering the true average abundance of the intracluster medium (ICM) is crucial for estimates of its global metal content, which in turn is linked to its past evolution and to the star formation history of the stellar component of the cluster. We analyze ... More
Critical exponents for higher-representation sources in 3D SU(3) gauge theory from CFTMay 30 2006We establish an exact mapping between the multiplication table of the irreducible representations of SU(3) and the fusion algebra of the two-dimensional conformal field theory in the same universality class of 3D SU(3) gauge theory at the deconfining ... More
The nonminimal scalar multiplet coupled to supersymmetric Yang-MillsDec 15 1997We consider the coupling of nonminimal scalar multiplets to supersymmetric Yang-Mills in four dimensions and compute the one-loop contribution to the low-energy effective action in the abelian sector. We show that the resulting theory realizes the dual ... More
A unit-level small area model with misclassified covariatesNov 09 2016Small area models are mixed effects regression models that link the small areas and borrow strength from similar domains. When the auxiliary variables used in the models are measured with error, small area estimators that ignore the measurement error ... More
Thermal emission from Isolated Neutron Stars and their surface magnetic field: going quadrupolar?Jan 06 2005In the last few years considerable observational resources have been devoted to study the thermal emission from isolated neutron stars. Detailed XMM and Chandra observations revealed a number of features in the X-ray pulse profile, like asymmetry, energy ... More
Superspace approach to anomalous dimensions in {\cal N}=4 SYMJul 09 2001Jul 26 2001In a {\cal N}=1 superspace setup and using dimensional regularization, we give a general and simple prescription to compute anomalous dimensions of composite operators in {\cal N}=4, SU(N) supersymmetric Yang-Mills theory, perturbatively in the coupling ... More
Orbital degrees of freedom as origin of magnetoelectric coupling in magnetiteOct 06 2010Oct 07 2010A microscopic understanding of magnetoelectricity, i.e. the coupling between magnetic (electric) properties and external electric (magnetic) fields, is a crucial milestone for future generations of electrically-controlled spintronic devices. Here, we ... More
Testing perturbation theory on the nf=0 static quark potentialSep 11 2001Sep 28 2001The perturbative expansion of static force and potential is reanalyzed concerning its practical applicability. A well behaved perturbative prediction is given by the integration of the renormalization group equation for the coupling $\alpha_{qq}(\mu=1/r)=(C_f)^{-1} ... More
Dynamic programming for infinite horizon boundary control problems of PDE's with age structureJun 26 2008We develop the dynamic programming approach for a family of infinite horizon boundary control problems with linear state equation and convex cost. We prove that the value function of the problem is the unique regular solution of the associated stationary ... More
A viewpoint on amalgamation classesSep 09 2010We provide a self-contained introduction to the classical theory of universal-homogeneous models (also known as generic structures, rich models, or Fra\"iss\'e limits). In the literature, most treatments restrict consideration to embeddings among finite ... More
Homotopy decomposition of a group of symplectomorphisms of $S^2 \times S^2$Mar 07 2003We continue the analysis, started by Abreu, McDuff and Anjos, of the topology of the group of symplectomorphisms of $S^2 \times S^2$ when the ratio of the areas of the two spheres lies in the interval (1,2]. We express the group, up to homotopy, as the ... More
On the segmentation of astronomical images via level-set methodsApr 09 2019Astronomical images are of crucial importance for astronomers since they contain a lot of information about celestial bodies that can not be directly accessible. Most of the information available for the analysis of these objects starts with sky explorations ... More
New tools for classifying Hamiltonian circle actions with isolated fixed pointsJun 14 2012For every compact almost complex manifold (M,J) equipped with a J-preserving circle action with isolated fixed points, a simple algebraic identity involving the first Chern class is derived. This enables us to construct an algorithm to obtain linear relations ... More
$AdS_3 \times S^3 \times M^4$ string S-matrices from unitarity cutsMay 30 2014Aug 13 2014Continuing the program initiated in arXiv:1304.1798 we investigate unitarity methods applied to two-dimensional integrable field theories. The one-loop computation is generalized to encompass theories with different masses in the asymptotic spectrum and ... More