Results for "Dario Tamascelli"

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Quantum annealing and the Schrödinger-Langevin-Kostin equationDec 03 2008We show, in the context of quantum combinatorial optimization, or quantum annealing, how the nonlinear Schr\"odinger-Langevin-Kostin equation can dynamically drive the system toward its ground state. We illustrate, moreover, how a frictional force of ... More
Quantum walks: a Markovian perspectiveJan 29 2008Jan 30 2008For a continuous-time quantum walk on a line the variance of the position observable grows quadratically in time, whereas, for its classical counterpart on the same graph, it exhibits a linear, diffusive, behaviour. A quantum walk, thus, propagates at ... More
Precursors of non-MarkovianityFeb 08 2019Using the paradigm of information backflow to characterize a non-Markovian evolution, we introduce so-called precursors of non-Markovianity, i.e. necessary properties that the system and environment state must exhibit at earlier times in order for an ... More
Interacting quantum walksOct 15 2009In this work we present the quantum mechanical computer proposed by Feynman in 1985 and, since then, widely cited but seldom used. The main feature of the model is the presence of a built in clocking mechanism managing for the ordered application of the ... More
A quantum-walk-inspired adiabatic algorithm for graph isomorphismJan 07 2014We present a 2-local quantum algorithm for graph isomorphism GI based on an adiabatic protocol. By exploiting continuous-time quantum-walks, we are able to avoid a mere diffusion over all possible configurations and to significantly reduce the dimensionality ... More
Quantum state transfer via Bloch oscillationsNov 30 2015The realization of reliable quantum channels, able to transfer a quantum state with high fidelity, is a fundamental step in the construction of scalable quantum devices. In this paper we describe a transmission scheme based on the genuinely quantum effect ... More
Time-dependent density functional theory for open spin chainsDec 24 2011The application of methods of time-dependent density functional theory (TDDFT) to systems of qubits provided the interesting possibility of simulating an assigned Hamiltonian evolution by means of an auxiliary Hamiltonian having different two-qubit interactions ... More
Dissipative dynamics of a spin system with three-body interactionJul 04 2011In this note we explicitly solve the Lindblad equation for a system of three spins with a three-body interaction, coupled to the environment by bath operators that inject or absorb spin carriers. We exemplify the properties of this solution in the context ... More
Quantum Timing and Synchronization ProblemsApr 05 2005Feynman's model of a quantum computer provides an example of a continuous-time quantum walk. Its clocking mechanism is an excitation of a basically linear chain of spins with occasional controlled jumps which allow for motion on a planar graph. The spreading ... More
An introduction to quantum annealingJul 05 2011Quantum Annealing, or Quantum Stochastic Optimization, is a classical randomized algorithm which provides good heuristics for the solution of hard optimization problems. The algorithm, suggested by the behaviour of quantum systems, is an example of proficuous ... More
Speed and entropy of an interacting continuous time quantum walkApr 10 2006Apr 27 2006We present some dynamic and entropic considerations about the evolution of a continuous time quantum walk implementing the clock of an autonomous machine. On a simple model, we study in quite explicit terms the Lindblad evolution of the clocked subsystem, ... More
Entropy generation in a model of reversible computationOct 17 2006We present a model in which, due to the quantum nature of the signals controlling the implementation time of successive unitary computational steps, \emph{physical} irreversibility appears in the execution of a \emph{logically} reversible computation. ... More
Noise-assisted quantum transport and computationDec 11 2012The transmission of an excitation along a spin chain can be hindered by the presence of small fixed imperfections that create trapping regions where the excitation may get caught (Anderson localization). A certain degree of noise, ensuing from the interaction ... More
Dynamical kickback and non commuting impurities in a spin chainFeb 25 2008Feb 27 2008In an interacting continuous time quantum walk, while the walker (the cursor) is moving on a graph, computational primitives (unitary operators associated with the edges) are applied to ancillary qubits (the register). The model with one walker was originally ... More
Grover's algorithm on a Feynman computerOct 16 2006We present an implementation of Grover's algorithm in the framework of Feynman's cursor model of a quantum computer. The cursor degrees of freedom act as a quantum clocking mechanism, and allow Grover's algorithm to be performed using a single, time-independent ... More
Graphics processing units accelerated semiclassical initial value representation molecular dynamicsDec 17 2013May 08 2014This paper presents a Graphics Processing Units (GPUs) implementation of the Semiclassical Initial Value Representation (SC-IVR) propagator for vibrational molecular spectroscopy calculations. The time-averaging formulation of the SC-IVR for power spectrum ... More
Characterization of qubit chains by Feynman probesJul 20 2016We address the characterization of qubit chains and assess the performances of local measurements compared to those provided by Feynman probes, i.e. nonlocal measurements realized by coupling a single qubit register to the chain. We show that local measurements ... More
A remark on the Generalized Hodge ConjectureSep 27 2010Oct 09 2012Let X be a smooth, projective variety over the field of complex numbers. On the space H of its rational cohomology of degree i we have the arithmetic filtration F^p. On the other hand, on the space of cohomology of degree i of X with complex coefficients ... More
Well-posedness of Multidimensional Diffusion Processes with Weakly Differentiable CoefficientsJul 06 2015Aug 25 2015We investigate well-posedness for martingale solutions of stochastic differential equations, under low regularity assumptions on their coefficients, widely extending some results first obtained by A. Figalli. Our main results are a very general equivalence ... More
The cohomological structure of generalized Killing spinor equationsJan 29 2018We review the topological structure, sitting in any supergravity theory, which has been recently discovered in arXiv: 1801.04940. We describe how such a structure allows for a cohomological reformulation of the generalized Killing spinor equations which ... More
The sets of star and semistar operations on semilocal Prüfer domainsJul 24 2017We study the sets of semistar and star operation on a semilocal Pr\"ufer domain, with an emphasis on which properties of the domain are enough to determine them. In particular, we show that these sets depend chiefly on the properties of the spectrum and ... More
Star operations on numerical semigroups: antichains and explicit resultsApr 11 2016We introduce an order on the set of non-divisorial ideals of a numerical semigroup $S$, and link antichains of this order with the star operations on $S$; subsequently, we use this order to find estimates on the number of star operations on $S$. We then ... More
Search for the θ_{13} Neutrino Mixing Angle Using Reactor Anti-NeutrinosFeb 01 2007The measurement of the last undetermined neutrino mixing angle \theta_{13} is the main goal of the future experimental research on neutrino oscillations. At present, \theta_{13} is only known to be much smaller than the two other mixing angles, \theta_{12} ... More
Nuclear Energy Density Functionals Constrained by Low-Energy QCDFeb 06 2008A microscopic framework of nuclear energy density functionals is reviewed, which establishes a direct relation between low-energy QCD and nuclear structure, synthesizing effective field theory methods and principles of density functional theory. Guided ... More
Graviton Production by a Thermal BathJul 24 2003Thermal fluctuations in the early universe plasma and in very hot astrophysical objects are an unavoidable source of gravitational waves (GW). Differently from previous studies on the subject, we approach this problem using methods based on field theory ... More
Orientation of non-spherical particles in an axisymmetric random flowJun 05 2012The dynamics of non-spherical rigid particles immersed in an axisymmetric random flow is studied analytically. The motion of the particles is described by Jeffery's equation; the random flow is Gaussian and has short correlation time.The stationary probability ... More
BV-capacities on Wiener Spaces and Regularity of the Maximum of the Wiener ProcessApr 30 2012Jan 07 2013We define a capacity C on abstract Wiener spaces and prove that, for any u with bounded variation, the total variation measure |Du| is absolutely continuous with respect to C: this enables us to extend the usual rules of calculus in many cases dealing ... More
Implications of the discovery of a Higgs boson with a mass of 125 GeVMar 26 2014The rather precise knowledge of the mass of the Higgs boson and of its couplings has important consequences for the physical phenomena taking place at the Fermi scale. We analyze some of these implications in the most motivated frameworks for physics ... More
On the number of relevant operators in asymptotically safe gravityJan 18 2013May 15 2013The asymptotic safety scenario of gravity conjectures that (i) the quantum field theory of gravity exists thanks to the presence of a non-trivial ultraviolet fixed point of the renormalization group, and that (ii) the fixed point has only a finite number ... More
Fractal properties of quantum spacetimeNov 10 2008Mar 25 2009We show that in general a spacetime having a quantum group symmetry has also a scale dependent fractal dimension which deviates from its classical value at short scales, a phenomenon that resembles what observed in some approaches to quantum gravity. ... More
Low-spin models for higher-spin LagrangiansMar 03 2011Higher-spin theories are most commonly modelled on the example of spin 2. While this is appropriate for the description of free irreducible spin-s particles, alternative options could be equally interesting. In particular Maxwell's equations provide the ... More
When the Zariski space is a Noetherian spaceJul 23 2018Jul 24 2018We characterize when the Zariski space $\mathrm{Zar}(K|D)$ (where $D$ is an integral domain, $K$ is a field containing $D$ and $D$ is integrally closed in $K$) and the set $\mathrm{Zar_{min}}(L|D)$ of its minimal elements are Noetherian spaces.
Non-compact subsets of the Zariski space of an integral domainMay 03 2017Let $V$ be a minimal valuation overring of an integral domain $D$ and let $\mathrm{Zar}(D)$ be the Zariski space of the valuation overrings of $D$. Starting from a result in the theory of semistar operations, we prove a criterion under which the set $\mathrm{Zar}(D)\setminus\{V\}$ ... More
Asymptotic stability of ground states in some Hamiltonian PDEs with symmetryJul 28 2011Jan 15 2013We consider a ground state (soliton) of a Hamiltonian PDE. We prove that if the soliton is orbitally stable, then it is also asymptotically stable. The main assumptions are transversal nondegeneracy of the manifold of the ground states, linear dispersion ... More
Oscillating shells: A model for a variable cosmic objectOct 23 1997A model for a possible variable cosmic object is presented. The model consists of a massive shell surrounding a compact object. The gravitational and self-gravitational forces tend to collapse the shell, but the internal tangential stresses oppose the ... More
Jaffard families and localizations of star operationsOct 05 2016We generalize the concept of localization of a star operation to flat overrings; subsequently, we investigate the possibility of representing the set $\mathrm{Star}(R)$ of star operations on $R$ as the product of $\mathrm{Star}(T)$, as $T$ ranges in a ... More
Lagrangian flows driven by $BV$ fields in Wiener spacesOct 21 2013We establish the renormalization property for essentially bounded solutions of the continuity equation associated to $BV$ fields in Wiener spaces, with values in the associated Cameron-Martin space; thus obtaining, by standard arguments, new uniqueness ... More
Zero noise limits using local timesJan 28 2013We consider a well-known family of SDEs with irregular drifts and the correspondent zero noise limits. Using (mollified) local times, we show which trajectories are selected. The approach is completely probabilistic and relies on elementary stochastic ... More
Disformal invariance of second order scalar-tensor theoriesMay 12 2014The Horndeski action is the most general one involving a metric and a scalar field that leads to second-order field equations in four dimensions. Being the natural extension of the well-known scalar-tensor theories, its structure and properties are worth ... More
Essential nature of Newton's constant in unimodular gravityNov 20 2015We point out that in unimodular gravity Newton's constant is an essential coupling, i.e. it is independent of field redefinitions. We illustrate the consequences of this fact by a calculation in a standard simple approximation, showing that in this case ... More
Asymptotic safety goes on shellJul 15 2011Nov 11 2011It is well known in quantum field theory that the off-shell effective action depends on the gauge choice and field parametrization used in calculating it. Nevertheless, the typical scheme in which the scenario of asymptotically safe gravity is investigated ... More
Towards a classification of stable semistar operations on a Prüfer domainJul 24 2017We study stable semistar operations defined over a Pr\"ufer domain, showing that, if every ideal of a Pr\"ufer domain $R$ has only finitely many minimal primes, every such closure can be described through semistar operations defined on valuation overrings ... More
Asymptotic stability of breathers in some Hamiltonian networks of weakly coupled oscillatorsSep 05 2012We consider a Hamiltonian chain of weakly coupled anharmonic oscillators. It is well known that if the coupling is weak enough then the system admits families of periodic solutions exponentially localized in space (breathers). In this paper we prove asymptotic ... More
BV-regularity for the Malliavin Derivative of the Maximum of the Wiener ProcessJan 07 2013We prove that, on the classical Wiener space, the random variable $\sup_{0\le t \le T} W_t$ admits a measure as second Malliavin derivative, whose total variation measure is finite and singular w.r.t.\ the Wiener measure.
Reducibility of 1-d Schrödinger equation with time quasiperiodic unbounded perturbations, IIJul 22 2016We study the Schr\"odinger equation on $\R$ with a potential behaving as $x^{2l}$ at infinity, $l\in[1,+\infty)$ and with a small time quasiperiodic perturbation. We prove that, if the perturbation belongs to a class of unbounded symbols including smooth ... More
Loop group actions on categories and Whittaker invariantsOct 18 2013We develop some aspects of the theory of $D$-modules on ind-schemes of pro-finite type. These notions are used to define $D$-modules on (algebraic) loop groups and, consequently, actions of loop groups on DG categories. Let $N$ be the maximal unipotent ... More
Critical behavior in spherical and hyperbolic spacesMar 26 2014Oct 02 2014We study the effects of curved background geometries on the critical behavior of scalar field theory. In particular we concentrate on two maximally symmetric spaces: $d$-dimensional spheres and hyperboloids. In the first part of the paper, by applying ... More
Quantum Gravity from Simplices: Analytical Investigations of Causal Dynamical TriangulationsJul 20 2007A potentially powerful approach to quantum gravity has been developed over the last few years under the name of Causal Dynamical Triangulations. Numerical simulations have given very interesting results in the cases of two, three and four spacetime dimension. ... More
The coupling of Poisson sigma models to topological backgroundsOct 17 2016Dec 13 2016We extend the coupling to the topological backgrounds, recently worked out for the 2-dimensional BF-model, to the most general Poisson sigma models. The coupling involves the choice of a Casimir function on the target manifold and modifies the BRST transformations. ... More
String theory triplets and higher-spin curvaturesJan 27 2010May 05 2010Unconstrained local Lagrangians for higher-spin gauge theories are bound to involve auxiliary fields, whose integration in the partition function generates geometric, effective actions expressed in terms of curvatures. When applied to the triplets, emerging ... More
Loop group actions on categories and Whittaker invariantsOct 18 2013Dec 13 2017We develop some aspects of the theory of $D$-modules on ind-schemes of pro-finite type. These notions are used to define $D$-modules on (algebraic) loop groups and, consequently, actions of loop groups on DG categories. Let $N$ be the maximal unipotent ... More
Decomposition and classification of length functionsJul 17 2018We study decompositions of length functions on integral domains as sums of length functions constructed from overrings. We find a standard representation when the integral domain admits a Jaffard family, when it is Noetherian and when it is a Pr\"ufer ... More
Mixed integer predictive control and shortest path reformulationMar 15 2010Mixed integer predictive control deals with optimizing integer and real control variables over a receding horizon. The mixed integer nature of controls might be a cause of intractability for instances of larger dimensions. To tackle this little issue, ... More
The coupling of Poisson sigma models to topological backgroundsOct 17 2016We extend the coupling to the topological backgrounds, recently worked out for the 2-dimensional BF-model, to the most general Poisson sigma models. The coupling involves the choice of a Casimir function on the target manifold and modifies the BRST transformations. ... More
A short proof of Stein's universal multiplier theoremAug 20 2014We give a short proof of Stein's universal multiplier theorem, purely by probabilistic methods, thus avoiding any use of harmonic analysis techniques (complex interpolation or transference methods).
Natural scalars in the NMSSMMay 13 2014In the motivated hypothesis that the scalar bosons of the Next-to-Minimal Supersymmetric Standard Model (NMSSM) be the lightest new particles around, a possible strategy to search for signs of the extra CP-even states is outlined. It is shown how the ... More
Scalar singlets at present and future collidersDec 23 2015A scalar singlet, coupled to the other particles only through its mixing with the Higgs boson, appears in several motivated extensions of the Standard Model. The prospects for the discovery of a generic singlet at the various stages of the LHC, as well ... More
Generalized geometry of two-dimensional vacuaOct 23 2013Dec 05 2014We derive the conditions for unbroken supersymmetry for a Mink_2, (2,0) vacuum, arising from Type II supergravity on a compact eight-dimensional manifold M_8. When specialized to internal manifolds enjoying SU(4)xSU(4) structure the resulting system is ... More
On the relation between local and geometric Lagrangians for higher spinsJan 21 2010Equations of motion for free higher-spin gauge fields of any symmetry can be formulated in terms of linearised curvatures. On the other hand, gauge invariance alone does not fix the form of the corresponding actions which, in addition, either contain ... More
Geometric massive higher spins and current exchangesApr 17 2008Generalised Fierz-Pauli mass terms allow to describe massive higher-spin fields on flat background by means of simple quadratic deformations of the corresponding geometric, massless Lagrangians. In this framework there is no need for auxiliary fields. ... More
Generalised connections and higher-spin equationsSep 21 2012Nov 15 2012We consider high-derivative equations obtained setting to zero the divergence of the higher-spin curvatures in metric-like form, showing their equivalence to the second-order equations emerging from the tensionless limit of open string field theory, which ... More
Holographic Renormalization and Ward Identities with the Hamilton-Jacobi MethodMay 07 2002Feb 03 2003A systematic procedure for performing holographic renormalization, which makes use of the Hamilton-Jacobi method, is proposed and applied to a bulk theory of gravity interacting with a scalar field and a U(1) gauge field in the Stueckelberg formalism. ... More
Energetic model of tumor growthDec 22 2004A macroscopic model of the tumor Gompertzian growth is proposed. This approach is based on the energetic balance among the different cell activities, described by methods of statistical mechanics and related to the growth inhibitor factors. The model ... More
Spontaneous breaking of translational invariance in non-commutative lambda phi^4 theory in two dimensionsNov 16 2007The spontaneous breaking of of translational invariance in non-commutative self-interacting scalar field theory in two dimensions is investigated by effective action techniques. The analysis confirms the existence of the stripe phase, already observed ... More
On persistence of invariant tori and a theorem by NekhoroshevNov 15 2001Mar 09 2002We give a proof of a theorem by N.N. Nekhoroshev concerning Hamiltonian systems with $n$ degrees of freedom and $s$ integrals of motion in involution, where $1 \le s \le n$. Such a theorem ensures persistence of $s$-dimensional invariant tori under suitable ... More
Modeling mutations in bacteria and human tissuesJul 07 2016This thesis is aimed at studying mutations, understood as trajectories in the DNA configuration space. An evolutive model of mutations in terms of Levy flights is proposed. The parameters of the model are estimated by means of data from the Long-Term ... More
Hydrogen Dissociation and Diffusion on Transition Metal(=Ti,Zr,V,Fe,Ru,Co,Rh,Ni,Pd,Cu,Ag)-doped Mg(0001) SurfacesNov 14 2008The kinetics of hydrogen absorption by magnesium bulk is affected by two main activated processes: the dissociation of the H$_2$ molecule and the diffusion of atomic H into the bulk. In order to have fast absorption kinetics both activated processed need ... More
Comments on the Casimir energy in supersymmetric field theoriesDec 23 2014Jul 08 2015We study the Casimir energy of four-dimensional supersymmetric gauge theories in the context of the rigid limit of new minimal supergravity. Firstly, revisiting the computation of the localized partition function on $S^1\times S^3$, we recover the supersymmetric ... More
Deformation of a flexible polymer in a random flow with long correlation timeDec 09 2010The effects induced by long temporal correlations of the velocity gradients on the dynamics of a flexible polymer are investigated by means of theoretical and numerical analysis of the Hookean and FENE dumbbell models in a random renewing flow. For Hookean ... More
Typing Regular Path Query Languages for Data GraphsJul 07 2015Regular path query languages for data graphs are essentially \emph{untyped}. The lack of type information greatly limits the optimization opportunities for query engines and makes application development more complex. In this paper we discuss a simple, ... More
Mutations as Levy flightsMay 31 2016Jul 01 2016Data on single-nucleotide polymorphisms and large chromosomal rearrangements, coming from a long time evolution experiment with Escherichia Coli, are analyzed in order to argue that mutations along a cell lineage can be modeled as Levy flights in the ... More
On the Dirac monopole's conceptJul 05 1999Jul 06 1999The Dirac monopole is discussed in view of the gauge invariance in Quantum Electrodynamics. It is shown the monopole existence implies the violation of the gauge invariance principle. The monopole field is essentially a longitudinal field and so a mass ... More
The monopoles in the structure of the electronJun 15 1999The classical electron is presented as made up of an electric charge and two Dirac monopoles of opposite charge performing a magnetic dipole. It is discussed that a valid variational principle for this system can be defined. The Dirac quantization condition ... More
A surgery result for the spectrum of the Dirichlet LaplacianOct 20 2014In this paper we give a method to geometrically modify an open set such that the first $k$ eigenvalues of the Dirichlet Laplacian and its perimeter are not increasing, its measure remains constant, and both perimeter and diameter decrease below a certain ... More
Existence of minimizers for spectral problemsDec 01 2011In this paper we show that any increasing functional of the first k eigenvalues of the Dirichlet Laplacian admits a (quasi-)open minimizer among the subsets of R^N of unit measure. In particular, there exists such a minimizer which is bounded, where the ... More
Thermodynamics of the Bose-Hubbard model in a Bogoliubov+U theoryJan 30 2015Jun 25 2015We derive the Bogoliubov+U formalism to study the thermodynamical properties of the Bose-Hubbard model. The framework can be viewed as the zero-frequency limit of bosonic dynamical mean-field theory (B-DMFT), but equally well as an extension of the mean-field ... More
Partial sum of matrix entries of representations of the symmetric group and its asymptoticsJun 29 2016Many aspects of the asymptotics of Plancherel distributed partitions have been studied in the past fifty years, in particular the limit shape, the distribution of the longest rows, characters of the associated representation matrices of the symmetric ... More
Distance Between Quantum Field Theories As A Measure Of Lorentz ViolationMay 21 2011Sep 16 2011We study the distance between symmetry-violating quantum field theories and the surface of symmetric theories. We use this notion to quantify how precise Lorentz symmetry is today, according to experimental data. The metric in parameter space is defined ... More
Spacetime condensation in (2+1)-dimensional CDT from a Horava-Lifshitz minisuperspace modelOct 03 2014Sep 04 2015A spacetime condensation phenomenon underlies the emergence of a macroscopic universe in causal dynamical triangulations, where the time extension of the condensate is strictly smaller than the total time. It has been known for some time that the volumes ... More
Perturbative running of the Immirzi parameterNov 03 2011We report on the renormalization of the Immirzi parameter found through perturbative one-loop calculations.
Imposing causality on a matrix modelDec 22 2008Jun 28 2009We introduce a new matrix model that describes Causal Dynamical Triangulations (CDT) in two dimensions. In order to do so, we introduce a new, simpler definition of 2D CDT and show it to be equivalent to the old one. The model makes use of ideas from ... More
Stability of spectral eigenspaces in nonlinear Schrodinger equationsAug 03 2006We consider the time-dependent non linear Schrodinger equations with a double well potential in dimensions d =1 and d=2. We prove, in the semiclassical limit, that the finite dimensional eigenspace associated to the lowest two eigenvalues of the linear ... More
Topological anomalies for Seifert 3-manifoldsNov 24 2014Oct 15 2015We study globally supersymmetric 3d gauge theories on curved manifolds by describing the coupling of 3d topological gauge theories, with both Yang-Mills and Chern-Simons terms in the action, to background topological gravity. In our approach the Seifert ... More
Generalized modularity matricesFeb 04 2015Various modularity matrices appeared in the recent literature on network analysis and algebraic graph theory. Their purpose is to allow writing as quadratic forms certain combinatorial functions appearing in the framework of graph clustering problems. ... More
A particle system approach to cell-cell adhesion modelsJan 20 2016We investigate micro-to-macroscopic derivations in two models of living cells, in presence to cell-cell adhesive interactions. We rigorously address two PDE-based models, one featuring non-local terms and another purely local, as a a result of a law of ... More
Complexity of control-affine motion planningSep 10 2013Dec 20 2013In this paper we study the complexity of the motion planning problem for control-affine systems. Such complexities are already defined and rather well-understood in the particular case of nonholonomic (or sub-Riemannian) systems. Our aim is to generalize ... More
Convergence rate for the hedging error of a path-dependent exampleMar 15 2016We consider a Brownian functional $F=g\bigl(\int_0^T \eta(s) dW_s\bigr)$ with $g \in L_2(\gamma)$ and a singular deterministic $\eta$. We deduce the $L_2$-convergence rate for the approximation $F^{(n)} = E F + \int_0^T \phi^{(n)}(s) dW_s$ for a class ... More
A complete and explicit solution to the three-dimensional problem of two fixed centresOct 27 2015We present for the first time an explicit, complete and closed-form solution to the three-dimensional problem of two fixed centres, based on Weierstrass elliptic and related functions. With respect to previous treatments of the problem, our solution is ... More
A transport inequality on the sphere obtained by mass transportJun 30 2014Using McCann's transportation map, we establish a transport inequality on compact manifolds with positive Ricci curvature. This inequality contains the sharp spectral comparison estimates.
Exploring the nucleus in the context of low-energy QCDDec 05 2003These lecture notes address a central problem of theoretical nuclear physics: how to establish a relationship between low-energy, non-perturbative QCD and nuclear phenomenology which includes both nuclear matter and finite nuclei. We develop a microscopic ... More
The fractional Brownian motion property of the turbulent refractive within Geometric OpticsJun 25 2003We introduce fractional Brownian motion processes (fBm) as an alternative model for the turbulent index of refraction. These processes allow to reconstruct most of the refractive index properties, but they are not differentiable. We overcome the apparent ... More
Holographic Renormalization Group and Fermionic Boundary DataJan 04 2001We discuss Holographic Renormalization Group equations in the presence of fermions and form fields in the bulk. The existence of a holographically dual quantum field theory for a given bulk gravity theory imposes consistency conditions on the ranks of ... More
Supersymmetry on curved spaces and superconformal anomaliesJul 24 2013Oct 01 2013We study the consequences of unbroken rigid supersymmetry of four-dimensional field theories placed on curved manifolds. We show that in Lorentzian signature the background vector field coupling to the R-current is determined by the Weyl tensor of the ... More
Self-adjoint extensions and stochastic completeness of the Laplace-Beltrami operator on conic and anticonic surfacesMay 22 2013Oct 07 2015We study the evolution of the heat and of a free quantum particle (described by the Schr\"odinger equation) on two-dimensional manifolds endowed with the degenerate Riemannian metric $ds^2=dx^2+|x|^{-2\alpha}d\theta^2$, where $x\in \mathbb R$, $\theta\in\mathbb ... More
CR electrons and positrons: what we have learned in the latest three years and future perspectivesOct 30 2011Nov 08 2011After the PAMELA finding of an increasing positron fraction above 10 GeV, the experimental evidence for the presence of a new electron and positron spectral component in the cosmic ray zoo has been recently confirmed by Fermi-LAT. We show that a simple ... More
Single-photon nonlinear optics with Kerr-type nanostructured materialsJan 24 2012We employ a quantum theory of the nonlinear optical response from an actual solid-state material possessing an intrinsic bulk contribution to the third-order nonlinear susceptibility (Kerr-type nonlinearity), which can be arbitrarily nanostructured to ... More
Spectral Variability of QSOs in the Optical BandJul 12 2000A new analysis of the variability of the spectral slope of PG QSOs has been performed, on the basis of recent literature data in the B and R photometric bands. Preliminary results confirm our previous findings concerning the increase of variability with ... More
On the construction of gauge theories from non critical type 0 stringsNov 24 1998Apr 14 1999We investigate Polyakov's proposal of constructing Yang-Mills theories by using non critical type 0 strings. We break conformal invariance by putting the system at finite temperature and find that the entropy of the cosmological solutions for these theories ... More
Thinking outside the box: fluctuations and finite size effectsJan 12 2014The isothermal compressibility of an interacting or non interacting system may be extracted from the fluctuations of the number of particles in a well chosen control volume. Finite size effects are prevalent and should then be accounted for to obtain ... More
Sgr A East as a possible high energy neutron factory in the Galactic CentreApr 14 2005Jul 28 2005Sgr A East is a supernova remnant located within few parsecs from the Galactic Centre (GC). There are good reasons to believe that this object is the source of the gamma-ray excess detected by HESS in the direction of the GC meaning that Sgr A East is ... More