Results for "M. Fabrizio"

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Surprises in the phase diagram of an Anderson impurity model for a single C$_{60}^{n-}$ moleculeJan 11 2005Sep 09 2005We find by Wilson numerical renormalization group and conformal field theory that a three-orbital Anderson impurity model for a C$_{60}^{n-}$ molecule has a very rich phase diagram which includes non-Fermi-liquid stable and unstable fixed points with ... More
Ordered phases of XXZ-symmetric spin-1/2 zigzag ladderOct 31 2003Using bosonization approach, we derive an effective low-energy theory for XXZ-symmetric spin-1/2 zigzag ladders and discuss its phase diagram by a variational approach. A spin nematic phase emerges in a wide part of the phase diagram, either critical ... More
Probabilistic Temporal Logic over Finite Traces (Technical Report)Mar 12 2019Temporal logics over finite traces have recently gained attention due to their use in real-world applications, in particular in business process modelling and planning. In real life, processes contain some degree of uncertainty that is impossible to handle ... More
Surface classification and local and global fundamental groups, IFeb 07 2006Apr 14 2006Given a smooth complex surface S, and a compact connected global normal crossings divisor $D = \cup_i D_i$, we consider the local fundamental group, i.e., the fundamental group Gamma of T-D, where T is a good tubular neighbourhood of D. One has a surjection ... More
Rational curves on fibered varietiesSep 25 2018Mar 13 2019Let $X$ be a projective variety with log terminal singularities and vanishing augmented irregularity. In this paper we prove that if $X$ admits a relatively minimal genus one fibration then it does contain a subvariety of codimension one covered by rational ... More
Deformations in the large of some complex manifolds, IJul 04 2003Main topic of the paper is the determination, for a compact complex manifold $M$, of the class of manifolds $X$ which are deformation equivalent to it. If $M$ is a complex torus, then also $X$ is so. After describing the structure of principal holomorphic ... More
Moduli spaces of surfaces and real structuresMar 12 2001Apr 29 2004We give infinite series of groups Gamma and of compact complex surfaces of general type S with fundamental group Gamma such that 1) Any surface S' with the same Euler number as S, and fundamental group Gamma, is diffeomorphic to S. 2) The moduli space ... More
Zeilberger's KOH theorem and the strict unimodality of q-binomial coefficientsNov 18 2013Apr 01 2014A recent nice result due to I. Pak and G. Panova is the strict unimodality of the $q$-binomial coefficients $\binom{a+b}{b}_q$ (see \cite{PP} and also \cite{PP2} for a slightly revised version of their theorem). Since their proof used representation theory ... More
The $h$-vector of a relatively compressed level algebraMar 24 2005Oct 31 2005The purpose of this note is to supply an upper and a lower bound (which are in general sharp) for the $h$-vector of a level algebra which is relatively compressed with respect to any arbitrary level algebra $A$. The useful concept of relatively compressed ... More
Irreducibility of the space of cyclic covers of algebraic curves of fixed numerical type and the irreducible components of $Sing (\bar{\mathfrak M_g})$Nov 01 2010We prove irreducibility for the space of cyclic covers of fixed numerical type between smooth projective curves, and also for the space of cyclic covers of prime order and of fixed numerical-combinatorial type between moduli-stable projective curves. ... More
On Bergeron's positivity problem for $q$-binomial coefficientsSep 18 2017Apr 11 2018F. Bergeron recently asked the intriguing question whether $\binom{b+c}{b}_q -\binom{a+d}{d}_q$ has nonnegative coefficients as a polynomial in $q$, whenever $a,b,c,d$ are positive integers, $a$ is the smallest, and $ad=bc$. We conjecture that, in fact, ... More
Cyclic Symmetry on Complex Tori and Bagnera-De Franchis ManifoldsFeb 05 2019We describe the possible linear actions of a cyclic group $G = \mathbb{Z} /n$ on a complex torus, using the cyclotomic exact sequence for the group algebra $\mathbb{Z} [G]$. The main application is devoted to a structure theorem for Bagnera-De Franchis ... More
Differentiable and deformation type of algebraic surfaces, real and symplectic structuresMay 10 2007Lecture 1: Projective and K\"ahler Manifolds, the Enriques classification, construction techniques. Lecture 2: Surfaces of general type and their Canonical models. Deformation equivalence and singularities. Lecture 3: Deformation and diffeomorphism, canonical ... More
Interval Conjectures for level Hilbert functionsMay 06 2007Sep 25 2007We conjecture that the set of all Hilbert functions of (artinian) level algebras enjoys a very natural form of regularity, which we call the {\em Interval Conjecture} (IC): If, for some positive integer $\alpha $, $(1,h_1,...,h_i,...,h_e)$ and $(1,h_1,...,h_i+\alpha ... More
Canonical surfaces of higher degreeFeb 04 2016We consider a family of surfaces of general type $S$ with $K_S$ ample, having $K^2_S = 24, p_g (S) = 6, q(S)=0$. We prove that for these surfaces the canonical system is base point free and yields an embedding $\Phi_1 : S \rightarrow \mathbb{P}^5$. This ... More
A global root-finding method for high dimensional problemsFeb 26 2009A method to solve the problem f(x) = 0 efficiently on any n-dimensional domain Omega under very broad hypoteses is proposed. The position of the root of f, assumed unique, is found by computing the center of mass of an Omega-shaped object having a singular ... More
Semi-Classical Quantization of the Many-Anyon SystemJul 29 1992We discuss the problem of N anyons in harmonic well, and derive the semi-classical spectrum as an exactly solvable limit of the many-anyon Hamiltonian. The relevance of our result to the solution of the anyon-gas model is discussed.
Superfluidity and vortices: A Ginzburg-Landau modelMay 30 2008The paper deals with the study of superfluidity by a Ginzburg-Landau model that investigates the material by a second order phase transition, in which any particle has simultaneouly a normal and superfluid motion. This pattern is able to describe the ... More
The Out-of-Equilibrium Time-Dependent Gutzwiller ApproximationApr 10 2012We review the recently proposed extension of the Gutzwiller approximation, M. Schiro' and M. Fabrizio, Phys. Rev. Lett. 105, 076401 (2010), designed to describe the out-of-equilibrium time-evolution of a Gutzwiller-type variational wave function for correlated ... More
Caustics of plane curves, their birationality and matrix projectionsApr 13 2013Jun 24 2013After recalling the notion of caustics of plane curves and basic equations, we first show the birationality of the caustic map for a general source point S in the plane. Then we prove more generally a theorem for curves D in the projective space of 3x3 ... 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
Deformation types of real and complex manifoldsNov 22 2001Jan 30 2002The Leit-Faden of the article (which is partially a survey) is a negative answer to the question whether, for a compact complex manifold which is a $K(\pi, 1)$ the diffeomorphism type determines the deformation type. We show that a deformation in the ... More
Discovering Process Maps from Event StreamsApr 08 2018Automated process discovery is a class of process mining methods that allow analysts to extract business process models from event logs. Traditional process discovery methods extract process models from a snapshot of an event log stored in its entirety. ... More
On the Weak Lefschetz Property for Artinian Gorenstein algebras of codimension threeFeb 22 2013Jan 01 2014We study the problem of whether an arbitrary codimension three graded artinian Gorenstein algebra has the Weak Lefschetz Property. We reduce this problem to checking whether it holds for all compressed Gorenstein algebras of odd socle degree. In the first ... More
Enhanced magnetic fluctuations in doped spin-Peierls systems: a single-chain model analysisMar 11 1997Mar 19 1997We analyze by means of real space Renormalization Group (RG) as well as by exact diagonalizations the properties of a single-chain model of a doped spin-Peierls system, where a major role is played by the localized moments created by the impurities. We ... More
Coexistence of antiferromagnetism and dimerization in a disordered spin-Peierls model: exact resultsJan 21 1997A model of disordered spin-Peierls system is considered, where domain walls are randomly distributed as a telegraph noise. For this realization of the disorder in an XX spin chain, we calculate exactly the density of states as well as several thermodynamic ... More
Spin-Charge separation in a model of two coupled chainsOct 19 1992A model of interacting electrons living on two chains coupled by a transverse hopping $t_\perp$, is solved exactly by bosonization technique. It is shown that $t_\perp$ does modify the shape of the Fermi surface also in presence of interaction, although ... More
A single chain analysis of doped quasi one dimensional spin 1 compounds: paramagnetic versus spin 1/2 dopingJun 16 1997We present a numerical study of single chain models of doped spin 1 compounds. We use low energy effective one-dimensional models for both the cases of paramagnetic and spin-1/2 doping. In the case of paramagnetic doping, the effective model is equivalent ... 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
Plasmonic lenses for tunable ultrafast electron emitters at the nanoscaleJul 04 2019Simultaneous spatio-temporal confinement of energetic electron pulses to femtosecond and nanometer scales is a topic of great interest in the scientific community, given the potential impact of such development on a wide spectrum of scientific and industrial ... More
Zero-Energy Modes from Coalescing Andreev States in a Two-Dimensional Semiconductor-Superconductor Hybrid PlatformMar 10 2017Oct 27 2017We investigate zero-bias conductance peaks that arise from coalescing subgap Andreev states, consistent with emerging Majorana zero modes, in hybrid semiconductor-superconductor wires defined in a two-dimensional InAs/Al heterostructure using top-down ... More
Long-distance entanglement and quantum teleportation in coupled cavity arraysJun 15 2009Oct 22 2009We introduce quantum spin models whose ground states allow for sizeable entanglement between distant spins. We discuss how spin models with global end-to-end entanglement realize quantum teleportation channels with optimal compromise between scalability ... More
Characterization of separability and entanglement in $(2\times{D})$- and $(3\times{D})$-dimensional systems by single-qubit and single-qutrit unitary transformationsJun 11 2007Aug 03 2007We investigate the geometric characterization of pure state bipartite entanglement of $(2\times{D})$- and $(3\times{D})$-dimensional composite quantum systems. To this aim, we analyze the relationship between states and their images under the action of ... More
AGN-stimulated Cooling of Hot Gas in Elliptical GalaxiesJan 14 2015May 05 2015We study the impact of relatively weak AGN feedback on the interstellar medium of intermediate and massive elliptical galaxies. We find that the AGN activity, while globally heating the ISM, naturally stimulates some degree of hot gas cooling on scales ... More
VART: A Tool for the Automatic Detection of Regression FaultsAug 07 2017In this paper we present VART, a tool for automatically revealing regression faults missed by regression test suites. Interestingly, VART is not limited to faults causing crashing or exceptions, but can reveal faults that cause the violation of application-specific ... More
The Cauchy transform in the slice hyperholomorphic setting and related topicsApr 29 2018In this paper we study the additive splitting associated to the quaternionic Cauchy transform defined by the Cauchy formula of slice hyperholomorphic functions. Moreover, we introduce and study the analogue of the fundamental solution of the global operator ... More
The double point formula with isolated singularities and canonical embeddingsFeb 12 2019Motivated by the embedding problem of canonical models in small codimension, we extend Severi's double point formula to the case of surfaces with rational double points, and we give more general double point formulae for varieties with isolated singularities. ... More
Benchmarking unsupervised near-duplicate image detectionJul 03 2019Unsupervised near-duplicate detection has many practical applications ranging from social media analysis and web-scale retrieval, to digital image forensics. It entails running a threshold-limited query on a set of descriptors extracted from the images, ... More
Twisted cotangent bundles of Hyperkähler manifoldsJun 27 2019Let $X$ be a Hyperk\"ahler manifold, and let $H$ be an ample divisor on $X$. We give a lower bound in terms of the Beauville-Bogomolov form $q(H)$ for the twisted cotangent bundle $\Omega_X \otimes H$ to be pseudoeffective. If $X$ is deformation equivalent ... More
Toulouse limit for the overscreened four-channel Kondo problemJul 26 1994We show that the spin dynamics of the 4--channel Kondo model is equivalent to the one of a model with a spin 1/2 impurity coupled to spin 1 conduction electrons. By abelian bosonization of the latter model we find a kind of Toulouse limit analogous to ... More
Mott physics beyond Brinkman-Rice scenarioJan 07 2017The main flaw of the well-known Brinkman-Rice description, obtained through the Gutzwiller approximation, of the paramagnetic Mott transition in the Hubbard model is in neglecting high-energy virtual processes that generate for instance the antiferromagnetic ... More
Real singular Del Pezzo surfaces and 3-folds fibred by rational curves, IIMar 14 2008Nov 05 2008Let W -> X be a real smooth projective 3-fold fibred by rational curves. J. Koll\'ar proved that, if W(R) is orientable, then a connected component N of W(R) is essentially either a Seifert fibred manifold or a connected sum of lens spaces. Our Main Theorem, ... More
Corporate payments networks and credit risk ratingNov 21 2017Sep 22 2018Aggregate and systemic risk in complex systems are emergent phenomena depending on two properties: the idiosyncratic risks of the elements and the topology of the network of interactions among them. While a significant attention has been given to aggregate ... More
$\mathfrak S_5$-symmetric equations for the Del Pezzo Surface of Degree 5Dec 27 2018Feb 28 2019The Del Pezzo surface $Y$ of degree 5 is the blow up of the plane in 4 general points, embedded in $\mathbb{P}^5$ by the system of cubics passing through these points. It is the simplest example of the Buchsbaum-Eisenbud theorem on arithmetically-Gorenstein ... More
Interacting one dimensional electron gas with open boundariesApr 04 1995We discuss the properties of interacting electrons on a finite chain with open boundary conditions. We extend the Haldane Luttinger liquid description to these systems and study how the presence of the boundaries modifies various correlation functions. ... More
Interplay of charge and spin dynamics after an interaction quench in the Hubbard modelNov 06 2017We investigate the unitary dynamics following a sudden increase $\Delta U>0$ of repulsion in the paramagnetic sector of the half-filled Hubbard model on a Bethe lattice, by means of a variational approach that combines a Gutzwiller wavefunction with a ... More
A Comparative Evaluation of Log-Based Process Performance Analysis TechniquesApr 11 2018Process mining has gained traction over the past decade and an impressive body of research has resulted in the introduction of a variety of process mining approaches measuring process performance. Having this set of techniques available, organizations ... More
Long-distance entanglement in many-body atomic and optical systemsSep 30 2009Nov 21 2009We discuss the phenomenon of long-distance entanglement in the ground state of quantum spin models, its use in high-fidelity and robust quantum communication, and its realization in many-body systems of ultracold atoms in optical lattices and in arrays ... More
Many-body breakdown of indirect gap in topological Kondo insulatorsMay 28 2016Sep 01 2016We show that the inclusion of nonlocal correlation effects in a variational wave function for the ground state of a topological Anderson lattice Hamiltonian is capable of describing both topologically trivial insulating phases and nontrivial ones characterized ... More
Reflection confocal nanoscopy using a super-oscillatory lensMar 21 2019A Superoscillatory lens (SOL) is known to produce a sub-diffraction hotspot which is useful for high-resolution imaging. However, high-energy rings called sidelobes coexist with the central hotspot. Additionally, SOLs have not yet been directly used to ... More
A volume maximizing canonical surface in 3-spaceAug 01 2006Answering a question posed by Enriques, we construct a minimal smooth algebraic surface $S$ of general type over the complex numbers with $K^2 = 45$ and $p_g = 4$, and with birational canonical map. Our surface is a regular (q=0) ball quotient which is ... More
Level algebras with bad propertiesDec 09 2005May 18 2006This paper can be seen as a continuation of the works contained in the recent preprints [Za], of the second author, and [Mi], of Juan Migliore. Our results are: 1). There exist codimension three artinian level algebras of type two which do not enjoy the ... More
On the evolution of cooling cores in X-ray galaxy clustersFeb 02 2008(Abridged) To define a framework for the formation and evolution of the cooling cores in X-ray galaxy clusters, we study how the physical properties change as function of the cosmic time in the inner regions of a 4 keV and 8 keV galaxy cluster under the ... More
Vector bundles on curves coming from Variation of Hodge StructuresMay 19 2015May 10 2016Fujita's second theorem for K\"ahler fibre spaces over a curve asserts that the direct image $V$ of the relative dualizing sheaf splits as the direct sum $ V = A \oplus Q$, where $A$ is ample and $Q$ is unitary flat. We focus on our negative answer (\cite{cd}) ... More
Double Kodaira fibrationsNov 14 2006The existence of a Kodaira fibration, i.e., of a fibration of a compact complex surface $S$ onto a complex curve $B$ which is a differentiable but not a holomorphic bundle, forces the geographical slope $ \nu(S) = c_1^2 (S) / c_2 (S)$ to lie in the interval ... More
Deformation of a generically finite map to a hypersurface embeddingAug 25 2017Mar 27 2018Motivated by the theory of Inoue-type varieties, we give a structure theorem for projective manifolds $W_0$ with the property of admitting a 1-parameter deformation where $W_t$ is a hypersurface in a projective smooth manifold $Z_t$. Their structure is ... More
Hyperelliptic Threefolds with group $D_4$, the Dihedral group of order 8May 04 2018We give a simple construction for the hyperelliptic threefolds with group $D_4$, thus completing the classification of hyperelliptic threefolds.
Teichmüller spaces of Generalized Hyperelliptic ManifoldsMay 03 2017In this paper we achieve a description of the connected components of Teichm\"uller space corresponding to Generalized Hyperelliptic Manifolds $X$. These are the quotients $ X = T/G$ of a complex torus $T$ by the free action of a finite group $G$, and ... More
The moduli space of Keum-Naie surfacesSep 09 2009Feb 14 2011Using a new description of Keum Naie surfaces and their fundamental group, we prove the following main result: Let S be a smooth complex projective surface which is homotopically equivalent to a Keum - Naie surface. Then S is a Keum - Naie surface. The ... More
A characterization of surfaces whose universal cover is the bidiskMar 20 2008Mar 26 2008We show that the universal cover of a compact complex surface $X$ is the bidisk $\HH \times \HH$, or $X$ is biholomorphic to $\PP^1 \times \PP^1$, if and only if $K_X^2 > 0$ and there exists an invertible sheaf $\eta$ such that $\eta^2\cong \hol_X$ and ... More
The Bicanonical map of fake projective planes with an automorphismJan 16 2018Mar 26 2018We show, for several fake projective planes with nontrivial automorphism group, that the bicanonical map is an embedding.
Merging Multiparty Protocols in Multiparty ChoreographiesFeb 26 2013Choreography-based programming is a powerful paradigm for defining communication-based systems from a global viewpoint. A choreography can be checked against multiparty protocol specifications, given as behavioural types, that may be instantiated indefinitely ... More
Can the periodic spectral modulations of the 236 SETI candidate Sloane Survey stars be due to Dark Matter effects?Nov 08 2016The search for dark matter (DM) is one of the most active and challenging areas of current research. Among the several effects of DM expected to be observable in astrophysics, very rapid stellar oscillations are expected to occur when certain types of ... More
Modeling the coupled return-spread high frequency dynamics of large tick assetsOct 16 2013Large tick assets, i.e. assets where one tick movement is a significant fraction of the price and bid-ask spread is almost always equal to one tick, display a dynamics in which price changes and spread are strongly coupled. We introduce a Markov-switching ... More
An Information System to Support and Monitor Clinical Trial ProcessJan 09 2013The demand of transparency of clinical research results, the need of accelerating the process of transferring innovation in the daily medical practice as well as assuring patient safety and product efficacy make it necessary to extend the functionality ... More
Fujita decomposition over higher dimensional baseSep 23 2017We generalize a result of Fujita, on the decomposition of Hodge bundles over curves, to the case of a higher dimensional base.
Error Probabilities for Halfspace DepthMay 13 2016Data depth functions are a generalization of one-dimensional order statistics and medians to real spaces of dimension greater than one; in particular, a data depth function quantifies the centrality of a point with respect to a data set or a probability ... More
Unlikely Intersections in families of abelian varieties and the polynomial Pell equationJan 09 2018Let S be a smooth irreducible curve defined over a number field k and consider an abelian scheme A over S and a curve C inside A, both defined over k. In previous works, we proved that when A is a fibered product of elliptic schemes, if C is not contained ... More
A Poincaré-Bendixson theorem for meromorphic connections on Riemann surfacesJun 26 2014We prove a Poincar\'e-Bendixson theorem describing the asymptotic behavior of geodesics for a meromorphic connection on a compact Riemann surface. We shall also briefly discuss the case of non-compact Riemann surfaces, and study in detail the geodesics ... More
The classification of Hyperelliptic threefoldsDec 23 2018We complete the classification of hyperelliptic threefolds, describing in an elementary way the hyperelliptic threefolds with group $D_4$. These are algebraic and form an irreducible 2-dimensional family. Our paper is fully self-contained.
Stanley's nonunimodal Gorenstein h-vector is optimalDec 04 2015We classify all possible $h$-vectors of graded artinian Gorenstein algebras in socle degree 4 and codimension $\leq 17$, and in socle degree 5 and codimension $\leq 25$. We obtain as a consequence that the least number of variables allowing the existence ... More
Direct Transition Between a Singlet Mott Insulator and a SuperconductorJan 26 2001May 15 2001We argue that a normal Fermi liquid and a singlet, spin gapped Mott insulator cannot be continuously connected, and that some intermediate phase must intrude between them. By explicitly working out a case study where the singlet insulator is stabilized ... More
Valley Jahn-Teller effect in twisted bilayer grapheneApr 12 2019The surprising insulating and superconducting states of narrow-band graphene twisted bilayers have been mostly discussed so far in terms of strong electron correlation, with little or no attention to phonons and electron-phonon effects. We found that, ... More
Valley Jahn-Teller effect in twisted bilayer grapheneApr 12 2019Apr 16 2019The surprising insulating and superconducting states of narrow-band graphene twisted bilayers have been mostly discussed so far in terms of strong electron correlation, with little or no attention to phonons and electron-phonon effects. We found that, ... More
Random Mass Dirac Fermions in Doped Spin-Peierls and Spin-Ladder systems: One-Particle Properties and Boundary EffectsJun 10 1997Quasi-one-dimensional spin-Peierls and spin-ladder systems are characterized by a gap in the spin-excitation spectrum, which can be modeled at low energies by that of Dirac fermions with a mass. In the presence of disorder these systems can still be described ... More
A generalization of a 1998 unimodality conjecture of Reiner and StantonNov 27 2017Jun 28 2018An interesting, and still wide open, conjecture of Reiner and Stanton predicts that certain "strange" symmetric differences of $q$-binomial coefficients are always nonnegative and unimodal. We extend their conjecture to a broader, and perhaps more natural, ... More
Canonical projections of irregular algebraic surfacesJul 26 2002A good canonical projection of a surface $S$ of general type is a morphism to the 3-dimensional projective space P^3 given by 4 sections of the canonical line bundle. To such a projection one associates the direct image sheaf F of the structure sheaf ... More
Entropy Evolution in Galaxy Groups and Clusters; A Comparison of External and Internal HeatingJan 29 2001X-ray observations of hot gas in galaxy groups indicate higher entropies than can be achieved in the accretion shocks as it fell into the dark halos. It has been proposed that this entropy excess results from some universal external heating process in ... More
Creation of the X-ray Cavity Jet and its Radio Lobe in M87/Virgo with Cosmic Rays; Relevance to Relic Radio SourcesNov 27 2007Dec 06 2007Young cavities in the X-ray emitting hot gas in galaxy clusters are often filled with radio synchrotron emission and it is widely thought that the cavities are inflated by these cosmic rays. At a later stage of its evolution, when the cavity becomes buoyant, ... More
Heated Cooling FlowsMar 22 2002In conventional models of galactic and cluster cooling flows widespread cooling (mass dropout) is assumed to avoid accumulation of unacceptably large central masses. However, recent XMM observations have failed to find spectral evidence for locally cooling ... More
Where Do Cooling Flows Cool?Feb 21 2000Although only about 5 percent of the total baryonic mass in luminous elliptical galaxies is in the form of cooled interstellar gas, it is concentrated within the optical effective radius r_e where it influences the local dynamical mass. The mass of cooled ... More
Chandra Detection of Massive Black Holes in Galactic Cooling FlowsOct 31 1999Anticipating forthcoming observations with the Chandra X-ray telescope, we describe the continuation of interstellar cooling flows deep into the cores of elliptical galaxies. Interstellar gas within about r = 50 parsecs from the massive black hole is ... More
The Catalan case of Armstrong's conjecture on simultaneous core partitionsDec 16 2013Dec 23 2014A beautiful recent conjecture of D. Armstrong predicts the average size of a partition that is simultaneously an $s$-core and a $t$-core, where $s$ and $t$ are coprime. Our goal is to prove this conjecture when $t=s+1$. These simultaneous $(s,s+1)$-core ... More
Simplicial complexes and Macaulay's inverse systemsDec 11 2007Feb 22 2009Let $\Delta$ be a simplicial complex on $V = \{x_1,...,x_n\}$, with Stanley-Reisner ideal $I_{\Delta}\subseteq R = k[x_1,...,x_n]$. The goal of this paper is to investigate the class of artinian algebras $A=A(\Delta,a_1,...,a_n)= R/(I_{\Delta},x_1^{a_1},...,x_n^{a_n})$, ... More
Some asymptotic results on q-binomial coefficientsMar 21 2015Nov 09 2015We look at the asymptotic behavior of the coefficients of the $q$-binomial coefficients (or Gaussian polynomials) $\binom{a+k}{k}_q$, when $k$ is fixed. We give a number of results in this direction, some of which involve Eulerian polynomials and their ... More
Phase separation in quasi incompressible fluids: Cahn-Hilliard model in the Cattaneo-Maxwell frameworkJun 03 2013In this paper we propose a mathematical model of phase separation for a quasi-incompressible binary mixture where the spinodal decomposition is induced by an heat flux governed by the Cattaneo-Maxwell equation. As usual, the phase separation is considered ... More
Design and Implementation of an Inertial Navigation System for Pedestrians Based on a Low-Cost MEMS IMUMar 07 2015Inertial navigation systems for pedestrians are infrastructure-less and can achieve sub-meter accuracy in the short/medium period. However, when low-cost inertial measurement units (IMU) are employed for their implementation, they suffer from a slowly ... More
Statistical Characterization and Mitigation of NLOS Bias in UWB Localization SystemsMar 13 2012Propagation in non-line-of-sight (NLOS) conditions is one of the major impairments in ultrawideband (UWB) wireless localization systems based on time-of-arrival (TOA) measurements. In this paper the problem of the joint statistical characterization of ... More
A phase field model for liquid-vapour phase transitionsDec 12 2010We propose a model describing the liquid-vapour phase transition according to a phase-field approach. The model takes up a setting proposed by the second author, where a phase field is introduced whose equilibrium values 0 and 1 are associated to the ... More
Some new surfaces with $p_g = q = 0$Oct 10 2003Dec 12 2003Motivated by a question by D. Mumford : can a computer classify all surfaces with $p_g = 0$ ? we try to show the complexity of the problem. We restrict it to the classification of the minimal surfaces of general type with $p_g = 0, K^2 = 8$ which are ... More
Accurate frequency referencing for fieldable dual-comb spectroscopyNov 30 2016A fieldable dual-comb spectrometer is described based on a "bootstrapped" frequency referencing scheme in which short-term optical phase coherence between combs is attained by referencing each to a free-running diode laser, whilst high frequency resolution ... More
Test results of a prototype device to calibrate the Large Size Telescope camera proposed for the Cherenkov Telescope ArrayAug 30 2017Sep 19 2017A Large Size air Cherenkov Telescope (LST) prototype, proposed for the Cherenkov Telescope Array (CTA), is under construction at the Canary Island of La Palma (Spain) this year. The LST camera, which comprises an array of about 500 photomultipliers (PMTs), ... More
Increasing d-wave superconductivity by on site repulsionOct 08 2002May 08 2003We study by Variational Monte Carlo an extended Hubbard model away from half filled band density which contains two competing nearest-neighbor interactions: a superexchange $J$ favoring d-wave superconductivity and a repulsion $V$ opposing against it. ... More
Quantum localization and bound state formation in Bose-Einstein condensatesJul 14 2010Nov 18 2010We discuss the possibility of exponential quantum localization in systems of ultracold bosonic atoms with repulsive interactions in open optical lattices without disorder. We show that exponential localization occurs in the maximally excited state of ... More
Symmetry and Variation of Hodge StructuresOct 10 2003Feb 26 2004The main problem addressed in the paper is the Torelli problem for n-dimensional varieties of general type, more specifically for varieties with ample canonical bundle. It asks under which geometrical condition for a variety the period map for the Hodge ... More
Multiple Andreev reflections in a quantum dot coupled to superconductors: Effects of spin-orbit couplingApr 03 2008Oct 22 2008We study the out-of-equilibrium current through a multilevel quantum dot contacted to two superconducting leads and in the presence of Rashba and Dresselhaus spin-orbit couplings, in the regime of strong dot-lead coupling. The multiple Andreev reflection ... More
Crystalline realizations of 1-motivesFeb 13 2003Nov 12 2003We consider the crystalline realization of Deligne's 1-motives in positive characteristics and prove a comparison theorem with the De Rham realization of liftings to zero characteristic. We then show that one dimensional crystalline cohomology of an algebraic ... More
Forcing the Strong Lefschetz and the Maximal Rank PropertiesApr 17 2008Oct 09 2008Three basic properties that standard graded artinian $k$-algebras may or may not enjoy are the Weak and Strong Lefschetz Properties and the Maximal Rank Property (respectively WLP, SLP, and MRP). In this paper we will assume that the base field $k$ has ... More
A note on the asymptotics of the number of O-sequences of given lengthOct 17 2018Apr 01 2019We look at the number $L(n)$ of $O$-sequences of length $n$. Recall that an $O$-sequence can be defined algebraically as the Hilbert function of a standard graded $k$-algebra, or combinatorially as the $f$-vector of a multicomplex. The sequence $L(n)$ ... More
Electron-phonon coupling close to a metal-insulator transition in one dimensionJul 18 1995We consider a one-dimensional system of electrons interacting via a short-range repulsion and coupled to phonons close to the metal-insulator transition at half filling. We argue that the metal-insulator transition can be described as a standard one dimensional ... More